The flow field induced by internal solitary waves(ISWs)is peculiar wherein water motion occurs in the whole water depth,and the strong shear near the pycnocline can be generated due to the opposite flow direction betw...The flow field induced by internal solitary waves(ISWs)is peculiar wherein water motion occurs in the whole water depth,and the strong shear near the pycnocline can be generated due to the opposite flow direction between the upper and lower layers,which is a potential threat to marine risers.In this paper,the flow field of ISWs is obtained with the Korteweg-de Vries(Kd V)equation for a two-layer fluid system.Then,a linear analysis is performed for the dynamic response of a riser with its two ends simply supported under the action of ISWs.The explicit expressions of the deflection and the moment of the riser are deduced based on the modal superposition method.The applicable conditions of the theoretical expressions are discussed.Through comparisons with the finite element simulations for nonlinear dynamic responses,it is proved that the theoretical expressions can roughly reveal the nonlinear dynamic response of risers under ISWs when the approximation for the linear analysis is relaxed to some extent.展开更多
Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The ...Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The databases of CNKI,Wanfang,Weipu,Chinese biomedical literature,Pubmed,Embase,and Cochrane Library were retrieved,and the randomized controlled studies that directly compared the efficacy of plate internal fixation and closed reduction external fixation in the treatment of distal radius fractures published publicly from the establishment of the database to April 2023 were collected.The two researchers independently screened the retrieved literature according to the inclusion and exclusion criteria,extracted data,used Cochrane risk bias assessment tool for quality assessment,and used RevMan 5.4 software for meta analysis.Results:A total of 10 randomized controlled trials were included,all of which were in English.There were 1042 patients in total,and 9 of them were rated as low risk.Meta analysis results showed that one year after the treatment of distal radius fracture with volar locking plate internal fixation,DASH score[MD=-5.64,95%CI(-7.21,-4.06),P<0.00001];One year later,PRWE score[MD=-5.90,95%CI(-8.88,-2.92),P=0.001];Palm flexion[MD=5.92,95%CI(1.29,10.55),P=0.01];Pronation[MD=2.48,95%CI(0.59,4.36),P=0.01];Postrotation[MD=4.73,95%CI(2.15,7.31),P=0.0003];Grip strength[MD=0.61,95%CI(0.12,1.10),P=0.02];palmar tilt angle[MD=9.84,95%CI(5.66,14.02),P<0.00001];Radial inclination[MD=4.33,95%CI(2.97,5.69),P<0.00001]was superior to closed reduction plaster or splint external fixation.One year later,the European Five dimensional Health Scale(EQ-5D-5L)score[MD=0.02,95%CI(-0.01,0.05),P=0.27];Back extension[MD=2.22,95%CI(-4.15,8.59),P=0.49];Ulnar deviation[MD=3.49,95%CI(-0.80,7.78),P=0.11];Radial deviation[MD=2.05,95%CI(-2.39,6.50),P=0.37];Ulnar variance[MD=-1.14,95%CI(-3.16,0.88),P=0.27];There was no significant difference in complications[MD=0.77,95%CI(0.54,1.10),P=0.16](P>0.05).Conclusion:Based on the current clinical data,internal fixation with volar locking plate is more conducive to mid-term DASH score and grip strength recovery than closed reduction plaster or splint external fixation,but there is no significant difference in the quality of life and complications of patients.For adult distal radius fractures,surgical indications should be carefully grasped,and non operative treatment should be given priority.展开更多
Gas–liquid multiphase flow is a significant phenomenon in chemical processes. The rising behaviors of single bubbles in the quiescent liquids have been investigated but the internal flow patterns and deformation rule...Gas–liquid multiphase flow is a significant phenomenon in chemical processes. The rising behaviors of single bubbles in the quiescent liquids have been investigated but the internal flow patterns and deformation rules of bubbles, which influence the mass transfer efficiency to a large extent, have received much less attention. In this paper, the volume of fluid method was used to calculate the bubble shapes, pressure, velocity distributions,and the flow patterns inside the bubbles. The rising behavior of the bubbles with four different initial diameters,i.e., 3 mm, 5 mm, 7 mm and 9 mm was investigated in four various liquids including water, 61.23% glycerol,86.73% glycerol and 100% glycerol. The results show that the liquid properties and bubble initial diameters have great impacts on bubble shapes. Moreover, flow patterns inside the bubbles with different initial diameters were analyzed and classified into three types under the condition of different bubble shapes. Three correlations for predicting the maximum internal circulation inside the bubbles in 86.73% glycerol were presented and the R-square values were all bigger than 0.98. Through analyzing the pressure and velocity distributions around the bubbles, four rules of bubble deformation were also obtained to explain and predict the shapes.展开更多
The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure mode...The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure models are difficult to establish through traditional statistical methods. Hence, the calculation of the occurrence probability of small sample events is often met with great uncertainty. In this study, the Bayesian statistical method is implemented to analyze the oil and gas leakages of FPSO internal turret, which is a typical small sample risk but could lead to severe losses.According to the corresponding failure mechanism, two Bayesian statistical models using the Weibull distribution and logarithmic normal distribution as the population distribution are established, and the posterior distribution of the corresponding parameters is calculated. The optimal Bayesian statistical model is determined according to the Bayesian information criterion and Akaike criterion. On the basis of the determined optimal model, the corresponding reliability index is solved to provide basic data for the subsequent risk assessments of FPSO systems.展开更多
An approximate theoretical expression for the current induced by long internal solitary waves is presented when the ocean is continuously or two-layer stratified. Particular attention is paid to characterizing velocit...An approximate theoretical expression for the current induced by long internal solitary waves is presented when the ocean is continuously or two-layer stratified. Particular attention is paid to characterizing velocity fields in terms of magnitude, flow components, and their temporal evolution/spatial distribution. For the two-layer case, the effects of the upper/lower layer depths and the relative layer density difference upon the induced current are further studied. The results show that the horizontal components are basically uniform in each layer with a shear at the interface. In contrast, the vertical counterparts vary monotonically in the direction of the water depth in each layer while they change sign across the interface or when the wave peak passes through. In addition, though the vertical components are generally one order of magnitude smaller than the horizontal ones, they can never be neglected in predicting the heave response of floating platforms in gravitationally neutral balance. Comparisons are made between the partial theoretical results and the observational field data. Future research directions regarding the internal wave induced flow field are also indicated.展开更多
A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis( SPA) method is proposed to calculate the con...A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis( SPA) method is proposed to calculate the contribution rate of PM2.5in Dongguan City. Due to geographic,meteorological factors and the low concentration of air pollutants in Qingxi area,the PM2.5in this place is mainly contributed by the regional transport of air pollutants from other inside areas of Dongguan,and less affected by the outside of Dongguan. So the concentration of PM2.5in Qingxi area can reflect the Dongguan's basic background concentration of PM2.5. On the basis of the basic background concentration,firstly the concentration of each pollutant components is divided into the internal part and the mixed part. Secondly using the source apportionment samples of five monitoring sites in Dongguan we can respectively construct a sample set A and an evaluation set B. Thirdly the SPA is operated onto the mixed part in terms of set B.At last the connection degree between the concentration of each pollutant components and external source and internal source will be calculated,that is the contribution rate. The research reveals that the contribution rate of internal source and external source of PM2.5in Dongguan City is 83%and 17% respectively,which roughly met expectations. This method is simple and effective and it can provide a reference for the government taking reduction measures to control PM2.5pollutants emission.展开更多
AIM: To evaluate the efficacy and safety of vitrectomy with internal limiting membrane(ILM) peeling for diabetic macular edema(DME). METHODS: The PubMed, Embase, Web of Science, Cochrane, SionMed, ClinicalTrials...AIM: To evaluate the efficacy and safety of vitrectomy with internal limiting membrane(ILM) peeling for diabetic macular edema(DME). METHODS: The PubMed, Embase, Web of Science, Cochrane, SionMed, ClinicalTrials.gov, CNKI databases and Wanfang databases, published until Oct. 2017, were searched to identify studies comparing the clinical outcomes following vitrectomy with and without ILM peeling, for treating DME. Pooled results were expressed as odds ratios(ORs) with corresponding 95% confidence intervals(CI) for vitrectomy with and without ILM peeling with regard to best corrected visual acuity(BCVA), central macular thickness(CMT), and complication incidents. RESULTS: A total of 14 studies involving 857 eyes were included of which three studies were Chinese and the rests were English literatures. Meta-analysis indicated that compared with vitrectomy alone, vitrectomy with ILM peeling could improve BCVA more obviously(OR=1.66, 95%CI: 1.12-2.46, P=0.01) and had higher rate of CMT reduction(OR=3.89, 95%CI: 1.37-11.11, P=0.01). There were significant statistical differences between the two surgical methods for both BCVA and CMT(P〈0.05). For the incidence of intraoperative and postoperative complications, the incidence of epiretinal membrane(ERM) was slightly lower in the ILM peeling group than the group without ILM peeling(OR=0.38, 95%CI: 0.07-2.00, P=0.25), although insignificant statistically. Other incidences of overall complications, iatrogenic peripheral retinal break and increased intraocular pressure indicated no significant difference between two groups(OR=1.19, 95%CI: 0.82-1.73, P=0.36; OR=1.21, 95%CI: 0.66-2.21, P=0.53; OR=1.34, 95%CI: 0.75-2.40, P=0.32). CONCLUSION: Vitrectomy is effective for DME and the effect can be improved by additional ILM peeling, especially for anatomical efficacy, without increasing the incidence of intraoperative and postoperative complications. However, it is imperative to gain more evaluation in the future due to the paucity of prospective randomized study.展开更多
Through the establishment of game model, this article formulates the intuitive and experiential understanding of regulation on listed companies' accounting information by using game analysis method, and from an econo...Through the establishment of game model, this article formulates the intuitive and experiential understanding of regulation on listed companies' accounting information by using game analysis method, and from an economic point of view, it analyzes how various parameters affect Internal Audit Department's nonfeasance probability and Auditing Office's supervision probability. Hope that this article can provide a reference for regulation on accounting information.展开更多
The new financial accounting system is the reorganization and refinement of the contents of the old financial accounting system, which not only maintains the basic contents of the original system, but also has its new...The new financial accounting system is the reorganization and refinement of the contents of the old financial accounting system, which not only maintains the basic contents of the original system, but also has its new characteristics. As far as the applications of the new accounting system are concerned, its practicability is very strong, and especially the application of the accounting in colleges and universities is very convenient. Moreover, the levels of the financial management under the new financial and accounting system are gradually improving. The purpose of this article is to explore the impact of the new financial accounting system on the internal auditing work in colleges and universities, hoping that this research will be helpful to the related auditing work in colleges and universities in the future.展开更多
The main contents of this paper is a new trend of employment status and employment difficulties of professional sports graduates in Jilin, and analysis on Jilin Physical graduates' Internal Education Causes of employ...The main contents of this paper is a new trend of employment status and employment difficulties of professional sports graduates in Jilin, and analysis on Jilin Physical graduates' Internal Education Causes of employment difficulties ,and how to effectively promote employment of Jilin education and sports undergraduate and graduate and implement measures. In this paper, we use literature, interview survey method, to analyze five professional employment situations of the graduates (physical education major, professional sports training, human movement science, and social sports professional, traditional sports professional). From this perspective of the internal education, employment difficulties of professional sports graduates are these : the concept of employment is a direct factor behind their employment difficulties ; university entrepreneurship education are indirect factors behind Kyrgyzstan employment difficulties ; training model obsolete is the root cause of their difficulties in finding jobs; college enrollment in recent years is its employment difficulties catalyst. This article analyzes the employment situation relating to education, and proposed employment countenueasures which professional sports graduates adapt to, namely: to meet market demand, improve professional structural adjustment; establish the concept of occupation after the first job; establish their own businesses and Multiple Employment Awareness; create a "multi-skilltype" physical training model.展开更多
AIM:To compare the outcomes of four adjuvants used for internal limiting membrane(ILM)peeling in macular hole surgery,including indocyanine green(ICG),brilliant blue G(BBG),triamcinolone(TA)and trypan blue(TB),through...AIM:To compare the outcomes of four adjuvants used for internal limiting membrane(ILM)peeling in macular hole surgery,including indocyanine green(ICG),brilliant blue G(BBG),triamcinolone(TA)and trypan blue(TB),through systematic review and random-effects Bayesian network Meta-analysis.METHODS:PubMed,Cochrane library databases and Web of Science were searched until August 2018 for clinical trials comparing the above four adjuvants.ORs for postoperative best corrected visual acuity(BCVA)improvement and primary macular hole closure rates were compared between the different adjuvants.RESULTS:Twenty-seven eligible articles were included.For postoperative BCVA improvement,results of BBGassisted peeling were significantly more favorable than those of ICG(WMD 0.08,95%credible interval 0.01-0.16)and TA ranked highest.No significant differences were found between any other two groups in postoperative BCVA improvement.For postoperative primary macular hole closure rates,BBG ranked highest.However,no significant differences were shown between any two groups.CONCLUSION:TA and BBG are the optimum adjuvants for achieving postoperative BCVA improvement macular hole surgery with adjuvant-assisted ILM peeling.Among all adjuvants,the use of BBG is associated with the highest postoperative macular hole closure rate.展开更多
AIM: To evaluate the effect of internal limiting membrane(ILM) peeling with indocyanine green(ICG), brilliant blue G(BBG), triamcinolone acetonide(TA), trypan blue(TB), or without dye for the treatment of idiopathic m...AIM: To evaluate the effect of internal limiting membrane(ILM) peeling with indocyanine green(ICG), brilliant blue G(BBG), triamcinolone acetonide(TA), trypan blue(TB), or without dye for the treatment of idiopathic macular hole(IMH). METHODS: A search was conducted using Pub Med, EMBASE, and CENTRAL(Cochrane Central Register of Controlled Trials) for related studies published before October 2018. RESULTS: A total of 29 studies and 2514 eyes were included in this network Meta-analysis. For IMH closure, the rank from the best to the worse treatment was: BBG, TB, TA, ICG, and no dye. There was a significant difference in postoperative IMH closure rate between BBG and no dye. The rank of the best to the worse treatment to improve visual acuity was: BBG, TB, no dye, TA, and ICG. The improvement rate of visual acuity after using BBG was significantly higher than ICG. The improvement rate of visual acuity was more favorable with TB than ICG, TA, and no dye. CONCLUSION: BBG can contribute to better anatomical and functional outcomes compared to other dyes for ILM peeling in patients with IMH. The results show that the best treatment of ILM peeling with dyes is BBG.展开更多
The original internal flooding probabilistic safety analysis (PSA) study of Krsko Nuclear Power Plant (two-loop Pressurized Water Reactor (PWR) plant of Westinghouse design) was performed in mid nineties and lim...The original internal flooding probabilistic safety analysis (PSA) study of Krsko Nuclear Power Plant (two-loop Pressurized Water Reactor (PWR) plant of Westinghouse design) was performed in mid nineties and limited to reactor core damage risk (Level 1 PSA). In 2003, it was, together with other safety and hazard analyses, subject to the Periodic Safety Review (PSR). In the PSR, it was stated that methodological PSA approaches and guidelines have evoluted during the past decade and several observations were provided, concerning the area screening process, residual risk and treatment of plant damage states and risk from radioactivity releases (i.e., Level 2 PSA). In order to address the PSR observations, upgrade ofKrsko NPP internal flooding PSA was undertaken. The area screening process was revisited in order to cover the areas without automatic reactor trip equipment. The model was extended to Level 2. Residual risk was estimated at both Level 1 and Level 2, in terms of core damage frequency (CDF) and large early release frequency (LERF), respectively.展开更多
An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave environments.The internal waves are numerically produced by tidal forcing over a continental slope using an ...An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave environments.The internal waves are numerically produced by tidal forcing over a continental slope using an ocean model.Three parameters(i.e.,internal wave,source depth,and water depth)contribute to the dynamic waveguide environments,and result in stochastic sound fields.The sensitivity of the transmission loss(TL)to environment parameters,statistical characteristics of the TL variation,and the associated physical mechanisms are investigated by the Sobol sensitivity analysis method,the Monte Carlo sampling,and the coupled normal mode theory,respectively.The results show that the TL is most sensitive to the source depth in the near field,resulted from the initial amplitudes of higher-order modes;while in middle and far fields,the internal waves are responsible for more than 80%of the total acoustic propagation contribution.In addition,the standard deviation of the TL in the near field and the shallow layer is smaller than those in the middle and far fields and the deep layer.展开更多
BACKGROUND Follicular lymphoma(FL)is a type of B-cell lymphoma that originates at the germinal center and has a low malignancy rate.FL has become the most common inert lymphoma in Europe and America but has a relative...BACKGROUND Follicular lymphoma(FL)is a type of B-cell lymphoma that originates at the germinal center and has a low malignancy rate.FL has become the most common inert lymphoma in Europe and America but has a relatively low incidence in Asia.AIM To explore the clinical features,curative effects,and prognostic factors of FL.METHODS Completed medical records of 49 patients with FL who were admitted to the Ningbo First Hospital from June 2010 to June 2021 were examined.These patients were definitively diagnosed by pathological biopsy or immunohistochemical staining.The diagnostic criteria were based on the 2008 World Health Organization classification of lymphomas.Ann Arbor staging was performed according to the imaging and bone marrow examination results.Risk stratification of all patients was performed based on the International Prognostic Index(IPI),age-adjusted IPI,Follicular Lymphoma International Prognosis Index(FLIPI),and FLIPI2 to compare the efficacy of different treatment regimens and analyze the related prognostic factors.RESULTS The age of onset in patients ranged from 24 to 76 years,with a median age of 51 years.Most patients developed the disease at 40–59 years of age,and the male:female ratio was 1.6:1.No significant difference was noted in the curative effect between the non-chemotherapy,combined chemotherapy,and other chemotherapy regimens(P>0.05).Hemoglobin(Hb)level<120 g/L,Ki-67 value>50%,bone marrow involvement,and clinical stagesⅢ–IV were associated with a poor prognosis of FL(P<0.05).However,the influence of other indicators was not statistically significant.Risk grouping was performed using the FLIPI,and the results showed that 24.5%,40.8%,and 34.7%of patients were in the low-,moderate-,and high-risk groups,respectively.According to the survival analysis results,the survival rate of patients was lower in the high-risk group than in the other low-risk and moderate-risk groups(P<0.05).CONCLUSION FL mainly occurs in middle-aged and elderly men,primarily affecting lymph nodes and bone marrow.Hb level,Ki-67 value,bone marrow involvement,and clinical staging were used to evaluate prognosis.展开更多
Shift-share analysis has been confirmed a useful approach in the study of regional economics and many kinds of extended shift-share models have been advanced and put into practice in economic studies, but few have hit...Shift-share analysis has been confirmed a useful approach in the study of regional economics and many kinds of extended shift-share models have been advanced and put into practice in economic studies, but few have hitherto been introduced and applied to the tourism research in China. Moreover understanding the spatially competitive relationship is of paramount importance for marketers, developers, and planners involved in tourism strategy development. Based on international tourism receipts from 1995 to 2004, this study aims at probing into the spatial competitiveness of interna- tional tourism in Jiangsu Province in comparison with its neighbors by applying a spatially extended shift-share model and a modified dynamic shift-share model. The empirical results illustrate that exceptional years may exist in the ap- plication of dynamic shift-share models. To solve this issue, modifications to dynamic shift-share model are put forward. The analytical results are not only presented but also explained by the comparison of background conditions of tourism development between Jiangsu and its key competitors. The conclusions can be drawn that the growth of international tourism receipts in Jiangsu mainly attributes to the national component and the competitive component and Zhejiang is the most important rival to Jiangsu during the period of 1995-2004. In order to upgrade the tourism competitiveness, it is indispensable for Jiangsu to take proper positioning, promoting and marketing strategies and to cooperate and integrate with its main rivals.展开更多
Investigation and analysis of natural tourism environment is the foundation and premise of tourism planning,development and management.Through investigating,classifying and evaluating natural tourism resources in Hain...Investigation and analysis of natural tourism environment is the foundation and premise of tourism planning,development and management.Through investigating,classifying and evaluating natural tourism resources in Hainan according to the Classification,Investigation and Evaluation of Tourism Resources(GB/T18972-2003),it was found that there are 4 principal categories,6 sub-categories and 61 basic types of natural tourism resources,accounting for 100%,94.1% and 85.9% of the national total respectively.There are 335 natural tourism resource units in Hainan,47 of them are superfine ones accounting for 14.0% of the total,225 excellent ones accounting for 67.2% of the total,48 common ones accounting for 14.3% of the total,62 of them without acquiring any grade,that is,18.5% of the total.Most of these resources are located in the mountainous areas in the central island,eastern coastal areas and Sanya City.Meanwhile,through collecting and sorting out the environmental quality bulletins and statistics of Hainan in recent 5 years,quality changes of its natural tourism environment have been analyzed,and it was found that the quality of water,air and sound on the whole in this island is fine,but a few study cities(towns) are suffering from serious noise pollution.Thus,besides enjoying its generally excellent ecological environment,Hainan Island is still faced with serious challenges.展开更多
BACKGROUND Pancreatic cancer,as the one of most fatal malignancies,remains a critical issue in the global burden of disease.AIM To estimate trends in pancreatic cancer incidence and mortality worldwide in the last thr...BACKGROUND Pancreatic cancer,as the one of most fatal malignancies,remains a critical issue in the global burden of disease.AIM To estimate trends in pancreatic cancer incidence and mortality worldwide in the last three decades.METHODS A descriptive epidemiological study was done.Pancreatic cancer incidence and mortality data were obtained from the database of the World Health Organization.Analysis of pancreatic cancer incidence and mortality during 2020 was performed.The age-standardized rates(ASRs,expressed per 100000)were presented.To estimate trends of incidence and mortality of pancreatic cancer,joinpoint regression analysis was used:the average annual percent change(AAPC)with the corresponding 95%confidence interval(95%CI)was calculated.Additionally,analysis was performed by sex and age.In this paper,the trend analysis included only countries with high and medium data quality.RESULTS A total of 495773(262865 male and 232908 female)new cases and 466003(246840 male and 219163 female)deaths from pancreatic cancer were reported worldwide in 2020.In both sexes,most of the new cases(191348;38.6%of the total)and deaths(182074;39.1%of the total)occurred in the Western Pacific Region.In both sexes,the highest ASRs were found in the European Region,while the lowest rates were reported in the South-East Asia Region.The general pattern of rising pancreatic cancer incidence and mortality was seen across countries worldwide in observed period.Out of all countries with an increase in pancreatic cancer incidence,females in France and India showed the most marked rise in incidence rates(AAPC=+3.9%and AAPC=+3.7%,respectively).Decreasing incidence trends for pancreatic cancer were observed in some countries,but without significance.Out of all countries with an increase in pancreatic cancer mortality rates,Turkmenistan showed the most marked rise both in males(AAPC=+10.0%,95%CI:7.4–12.5)and females(AAPC=+6.4%,95%CI:3.5–9.5).The mortality trends of pancreatic cancer were decreasing in both sexes only in Canada and Mexico.CONCLUSION Further research is needed to explain the cause of large international differences in incidence and mortality trends of pancreatic cancer in last three decades.展开更多
Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual ener...Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual energy content can be usefully recovered,for example in Organic Rankine Cycles(ORC).This technology has been largely consolidated in stationary power plants but not yet for mobile applications,such as road transport,due to the limitations in the layout and to the constraints on the size and weight of the ORC system.An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated.The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation.The waste thermal power has been considered as heat input for the ORC plant simulation.A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance.The exergy analysis of the ORC was performed comparing different working fluids:R601,R1233zd(E)and two zeotropic blends of the two organic pure fluids.The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.展开更多
Based on the analysis of rice planting and export development in Heilongjiang Province in 2013-2021,this paper comprehensively used three export competitiveness analysis methods,namely,trade competitiveness index,reve...Based on the analysis of rice planting and export development in Heilongjiang Province in 2013-2021,this paper comprehensively used three export competitiveness analysis methods,namely,trade competitiveness index,revealed comparative advantage(RCA)analysis and international market share analysis,to compare the four major rice exporters in the world and the three major rice export provinces and cities in China.Besides,it evaluated the rice export competitiveness of Heilongjiang Province from multiple perspectives.It analyzed the reasons for low competitiveness in terms of export product structure,export market structure,production and processing technology,and brand building.Finally,it is recommended to clarify the positioning of rice export quality and take more measures to ensure product quality;improve the level of industrialization of rice production and processing,and extend the rice industry chain;develop diversified rice export markets and improve export flexibility;adhere to the principle of"opening the door and going out",expand the international popularity of high-quality brands,so as to enhance the rice export competitiveness of Heilongjiang Province.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.12132018,11972352,12202455)the Strategic Priority Research Program of the Chinese Academy of Sciences of China(No.XDA22000000)。
文摘The flow field induced by internal solitary waves(ISWs)is peculiar wherein water motion occurs in the whole water depth,and the strong shear near the pycnocline can be generated due to the opposite flow direction between the upper and lower layers,which is a potential threat to marine risers.In this paper,the flow field of ISWs is obtained with the Korteweg-de Vries(Kd V)equation for a two-layer fluid system.Then,a linear analysis is performed for the dynamic response of a riser with its two ends simply supported under the action of ISWs.The explicit expressions of the deflection and the moment of the riser are deduced based on the modal superposition method.The applicable conditions of the theoretical expressions are discussed.Through comparisons with the finite element simulations for nonlinear dynamic responses,it is proved that the theoretical expressions can roughly reveal the nonlinear dynamic response of risers under ISWs when the approximation for the linear analysis is relaxed to some extent.
基金2022 Key Specialty Construction Project of Traditional Chinese Medicine:Traditional Chinese Orthopedics and Traumatology Department (No.962042)2020 Regional Traditional Chinese Medicine (Orthopedics and Traumatology)Diagnosis and Treatment Center (Jin Wei Zhong[2020]No.5)。
文摘Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The databases of CNKI,Wanfang,Weipu,Chinese biomedical literature,Pubmed,Embase,and Cochrane Library were retrieved,and the randomized controlled studies that directly compared the efficacy of plate internal fixation and closed reduction external fixation in the treatment of distal radius fractures published publicly from the establishment of the database to April 2023 were collected.The two researchers independently screened the retrieved literature according to the inclusion and exclusion criteria,extracted data,used Cochrane risk bias assessment tool for quality assessment,and used RevMan 5.4 software for meta analysis.Results:A total of 10 randomized controlled trials were included,all of which were in English.There were 1042 patients in total,and 9 of them were rated as low risk.Meta analysis results showed that one year after the treatment of distal radius fracture with volar locking plate internal fixation,DASH score[MD=-5.64,95%CI(-7.21,-4.06),P<0.00001];One year later,PRWE score[MD=-5.90,95%CI(-8.88,-2.92),P=0.001];Palm flexion[MD=5.92,95%CI(1.29,10.55),P=0.01];Pronation[MD=2.48,95%CI(0.59,4.36),P=0.01];Postrotation[MD=4.73,95%CI(2.15,7.31),P=0.0003];Grip strength[MD=0.61,95%CI(0.12,1.10),P=0.02];palmar tilt angle[MD=9.84,95%CI(5.66,14.02),P<0.00001];Radial inclination[MD=4.33,95%CI(2.97,5.69),P<0.00001]was superior to closed reduction plaster or splint external fixation.One year later,the European Five dimensional Health Scale(EQ-5D-5L)score[MD=0.02,95%CI(-0.01,0.05),P=0.27];Back extension[MD=2.22,95%CI(-4.15,8.59),P=0.49];Ulnar deviation[MD=3.49,95%CI(-0.80,7.78),P=0.11];Radial deviation[MD=2.05,95%CI(-2.39,6.50),P=0.37];Ulnar variance[MD=-1.14,95%CI(-3.16,0.88),P=0.27];There was no significant difference in complications[MD=0.77,95%CI(0.54,1.10),P=0.16](P>0.05).Conclusion:Based on the current clinical data,internal fixation with volar locking plate is more conducive to mid-term DASH score and grip strength recovery than closed reduction plaster or splint external fixation,but there is no significant difference in the quality of life and complications of patients.For adult distal radius fractures,surgical indications should be carefully grasped,and non operative treatment should be given priority.
基金Supported by the National Natural Science Foundation of China(21276132)the Transformation Project of Scientific and Technological Achievements of Qingdao(16-6-2-50-nsh)
文摘Gas–liquid multiphase flow is a significant phenomenon in chemical processes. The rising behaviors of single bubbles in the quiescent liquids have been investigated but the internal flow patterns and deformation rules of bubbles, which influence the mass transfer efficiency to a large extent, have received much less attention. In this paper, the volume of fluid method was used to calculate the bubble shapes, pressure, velocity distributions,and the flow patterns inside the bubbles. The rising behavior of the bubbles with four different initial diameters,i.e., 3 mm, 5 mm, 7 mm and 9 mm was investigated in four various liquids including water, 61.23% glycerol,86.73% glycerol and 100% glycerol. The results show that the liquid properties and bubble initial diameters have great impacts on bubble shapes. Moreover, flow patterns inside the bubbles with different initial diameters were analyzed and classified into three types under the condition of different bubble shapes. Three correlations for predicting the maximum internal circulation inside the bubbles in 86.73% glycerol were presented and the R-square values were all bigger than 0.98. Through analyzing the pressure and velocity distributions around the bubbles, four rules of bubble deformation were also obtained to explain and predict the shapes.
基金financially supported by the National International Science and Technology Cooperation Specific Projectthe Development of Risk Assessment Software for Floating Offshore Wind Turbine(Grant No.2013DFE73060)the Development of Failure Database and Risk Assessment System for FPSO(Grant No.G014614002)
文摘The load and corrosion caused by the harsh marine environment lead to the severe degradation of offshore equipment and to their compromised security and reliability. In the quantitative risk analysis, the failure models are difficult to establish through traditional statistical methods. Hence, the calculation of the occurrence probability of small sample events is often met with great uncertainty. In this study, the Bayesian statistical method is implemented to analyze the oil and gas leakages of FPSO internal turret, which is a typical small sample risk but could lead to severe losses.According to the corresponding failure mechanism, two Bayesian statistical models using the Weibull distribution and logarithmic normal distribution as the population distribution are established, and the posterior distribution of the corresponding parameters is calculated. The optimal Bayesian statistical model is determined according to the Bayesian information criterion and Akaike criterion. On the basis of the determined optimal model, the corresponding reliability index is solved to provide basic data for the subsequent risk assessments of FPSO systems.
基金supported by the Ministry of Science and Technology(MST) of China and Chinese Academy of Sciences (CAS) (863)(2006AA09A103-4)Knowledge Innovation Program(KJCX-YW-L02)
文摘An approximate theoretical expression for the current induced by long internal solitary waves is presented when the ocean is continuously or two-layer stratified. Particular attention is paid to characterizing velocity fields in terms of magnitude, flow components, and their temporal evolution/spatial distribution. For the two-layer case, the effects of the upper/lower layer depths and the relative layer density difference upon the induced current are further studied. The results show that the horizontal components are basically uniform in each layer with a shear at the interface. In contrast, the vertical counterparts vary monotonically in the direction of the water depth in each layer while they change sign across the interface or when the wave peak passes through. In addition, though the vertical components are generally one order of magnitude smaller than the horizontal ones, they can never be neglected in predicting the heave response of floating platforms in gravitationally neutral balance. Comparisons are made between the partial theoretical results and the observational field data. Future research directions regarding the internal wave induced flow field are also indicated.
基金Supported by National Natural Science Foundation of China(71171089)Research for PM_(2.5) Contamination Characteristics and Prevention and Control Countermeasures in Dongguan City(Dongcaidan[2013]222)
文摘A problem of the air pollution control in China is getting to know a regional contribution rate of internal and external source of PM2.5. In this paper,Set Pair Analysis( SPA) method is proposed to calculate the contribution rate of PM2.5in Dongguan City. Due to geographic,meteorological factors and the low concentration of air pollutants in Qingxi area,the PM2.5in this place is mainly contributed by the regional transport of air pollutants from other inside areas of Dongguan,and less affected by the outside of Dongguan. So the concentration of PM2.5in Qingxi area can reflect the Dongguan's basic background concentration of PM2.5. On the basis of the basic background concentration,firstly the concentration of each pollutant components is divided into the internal part and the mixed part. Secondly using the source apportionment samples of five monitoring sites in Dongguan we can respectively construct a sample set A and an evaluation set B. Thirdly the SPA is operated onto the mixed part in terms of set B.At last the connection degree between the concentration of each pollutant components and external source and internal source will be calculated,that is the contribution rate. The research reveals that the contribution rate of internal source and external source of PM2.5in Dongguan City is 83%and 17% respectively,which roughly met expectations. This method is simple and effective and it can provide a reference for the government taking reduction measures to control PM2.5pollutants emission.
文摘AIM: To evaluate the efficacy and safety of vitrectomy with internal limiting membrane(ILM) peeling for diabetic macular edema(DME). METHODS: The PubMed, Embase, Web of Science, Cochrane, SionMed, ClinicalTrials.gov, CNKI databases and Wanfang databases, published until Oct. 2017, were searched to identify studies comparing the clinical outcomes following vitrectomy with and without ILM peeling, for treating DME. Pooled results were expressed as odds ratios(ORs) with corresponding 95% confidence intervals(CI) for vitrectomy with and without ILM peeling with regard to best corrected visual acuity(BCVA), central macular thickness(CMT), and complication incidents. RESULTS: A total of 14 studies involving 857 eyes were included of which three studies were Chinese and the rests were English literatures. Meta-analysis indicated that compared with vitrectomy alone, vitrectomy with ILM peeling could improve BCVA more obviously(OR=1.66, 95%CI: 1.12-2.46, P=0.01) and had higher rate of CMT reduction(OR=3.89, 95%CI: 1.37-11.11, P=0.01). There were significant statistical differences between the two surgical methods for both BCVA and CMT(P〈0.05). For the incidence of intraoperative and postoperative complications, the incidence of epiretinal membrane(ERM) was slightly lower in the ILM peeling group than the group without ILM peeling(OR=0.38, 95%CI: 0.07-2.00, P=0.25), although insignificant statistically. Other incidences of overall complications, iatrogenic peripheral retinal break and increased intraocular pressure indicated no significant difference between two groups(OR=1.19, 95%CI: 0.82-1.73, P=0.36; OR=1.21, 95%CI: 0.66-2.21, P=0.53; OR=1.34, 95%CI: 0.75-2.40, P=0.32). CONCLUSION: Vitrectomy is effective for DME and the effect can be improved by additional ILM peeling, especially for anatomical efficacy, without increasing the incidence of intraoperative and postoperative complications. However, it is imperative to gain more evaluation in the future due to the paucity of prospective randomized study.
文摘Through the establishment of game model, this article formulates the intuitive and experiential understanding of regulation on listed companies' accounting information by using game analysis method, and from an economic point of view, it analyzes how various parameters affect Internal Audit Department's nonfeasance probability and Auditing Office's supervision probability. Hope that this article can provide a reference for regulation on accounting information.
文摘The new financial accounting system is the reorganization and refinement of the contents of the old financial accounting system, which not only maintains the basic contents of the original system, but also has its new characteristics. As far as the applications of the new accounting system are concerned, its practicability is very strong, and especially the application of the accounting in colleges and universities is very convenient. Moreover, the levels of the financial management under the new financial and accounting system are gradually improving. The purpose of this article is to explore the impact of the new financial accounting system on the internal auditing work in colleges and universities, hoping that this research will be helpful to the related auditing work in colleges and universities in the future.
文摘The main contents of this paper is a new trend of employment status and employment difficulties of professional sports graduates in Jilin, and analysis on Jilin Physical graduates' Internal Education Causes of employment difficulties ,and how to effectively promote employment of Jilin education and sports undergraduate and graduate and implement measures. In this paper, we use literature, interview survey method, to analyze five professional employment situations of the graduates (physical education major, professional sports training, human movement science, and social sports professional, traditional sports professional). From this perspective of the internal education, employment difficulties of professional sports graduates are these : the concept of employment is a direct factor behind their employment difficulties ; university entrepreneurship education are indirect factors behind Kyrgyzstan employment difficulties ; training model obsolete is the root cause of their difficulties in finding jobs; college enrollment in recent years is its employment difficulties catalyst. This article analyzes the employment situation relating to education, and proposed employment countenueasures which professional sports graduates adapt to, namely: to meet market demand, improve professional structural adjustment; establish the concept of occupation after the first job; establish their own businesses and Multiple Employment Awareness; create a "multi-skilltype" physical training model.
文摘AIM:To compare the outcomes of four adjuvants used for internal limiting membrane(ILM)peeling in macular hole surgery,including indocyanine green(ICG),brilliant blue G(BBG),triamcinolone(TA)and trypan blue(TB),through systematic review and random-effects Bayesian network Meta-analysis.METHODS:PubMed,Cochrane library databases and Web of Science were searched until August 2018 for clinical trials comparing the above four adjuvants.ORs for postoperative best corrected visual acuity(BCVA)improvement and primary macular hole closure rates were compared between the different adjuvants.RESULTS:Twenty-seven eligible articles were included.For postoperative BCVA improvement,results of BBGassisted peeling were significantly more favorable than those of ICG(WMD 0.08,95%credible interval 0.01-0.16)and TA ranked highest.No significant differences were found between any other two groups in postoperative BCVA improvement.For postoperative primary macular hole closure rates,BBG ranked highest.However,no significant differences were shown between any two groups.CONCLUSION:TA and BBG are the optimum adjuvants for achieving postoperative BCVA improvement macular hole surgery with adjuvant-assisted ILM peeling.Among all adjuvants,the use of BBG is associated with the highest postoperative macular hole closure rate.
基金Supported by the National Natural Science Foundation of China (No.81870686)the Natural Science Foundation of Beijing Municipal (No.7184201)the Capital’s Funds for Health Improvement and Research (No.2018-12021)
文摘AIM: To evaluate the effect of internal limiting membrane(ILM) peeling with indocyanine green(ICG), brilliant blue G(BBG), triamcinolone acetonide(TA), trypan blue(TB), or without dye for the treatment of idiopathic macular hole(IMH). METHODS: A search was conducted using Pub Med, EMBASE, and CENTRAL(Cochrane Central Register of Controlled Trials) for related studies published before October 2018. RESULTS: A total of 29 studies and 2514 eyes were included in this network Meta-analysis. For IMH closure, the rank from the best to the worse treatment was: BBG, TB, TA, ICG, and no dye. There was a significant difference in postoperative IMH closure rate between BBG and no dye. The rank of the best to the worse treatment to improve visual acuity was: BBG, TB, no dye, TA, and ICG. The improvement rate of visual acuity after using BBG was significantly higher than ICG. The improvement rate of visual acuity was more favorable with TB than ICG, TA, and no dye. CONCLUSION: BBG can contribute to better anatomical and functional outcomes compared to other dyes for ILM peeling in patients with IMH. The results show that the best treatment of ILM peeling with dyes is BBG.
文摘The original internal flooding probabilistic safety analysis (PSA) study of Krsko Nuclear Power Plant (two-loop Pressurized Water Reactor (PWR) plant of Westinghouse design) was performed in mid nineties and limited to reactor core damage risk (Level 1 PSA). In 2003, it was, together with other safety and hazard analyses, subject to the Periodic Safety Review (PSR). In the PSR, it was stated that methodological PSA approaches and guidelines have evoluted during the past decade and several observations were provided, concerning the area screening process, residual risk and treatment of plant damage states and risk from radioactivity releases (i.e., Level 2 PSA). In order to address the PSR observations, upgrade ofKrsko NPP internal flooding PSA was undertaken. The area screening process was revisited in order to cover the areas without automatic reactor trip equipment. The model was extended to Level 2. Residual risk was estimated at both Level 1 and Level 2, in terms of core damage frequency (CDF) and large early release frequency (LERF), respectively.
基金the National Key Research and Development Program of China(Grant No.2020YFA0607900)the National Natural Science Foundation of China(Grant Nos.42176019 and 11874061)the Youth Innovation Promotion Association CAS(Grant No.2021023).
文摘An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave environments.The internal waves are numerically produced by tidal forcing over a continental slope using an ocean model.Three parameters(i.e.,internal wave,source depth,and water depth)contribute to the dynamic waveguide environments,and result in stochastic sound fields.The sensitivity of the transmission loss(TL)to environment parameters,statistical characteristics of the TL variation,and the associated physical mechanisms are investigated by the Sobol sensitivity analysis method,the Monte Carlo sampling,and the coupled normal mode theory,respectively.The results show that the TL is most sensitive to the source depth in the near field,resulted from the initial amplitudes of higher-order modes;while in middle and far fields,the internal waves are responsible for more than 80%of the total acoustic propagation contribution.In addition,the standard deviation of the TL in the near field and the shallow layer is smaller than those in the middle and far fields and the deep layer.
基金Supported by Zhejiang TCM Science and Technology Project,No.2023ZL653。
文摘BACKGROUND Follicular lymphoma(FL)is a type of B-cell lymphoma that originates at the germinal center and has a low malignancy rate.FL has become the most common inert lymphoma in Europe and America but has a relatively low incidence in Asia.AIM To explore the clinical features,curative effects,and prognostic factors of FL.METHODS Completed medical records of 49 patients with FL who were admitted to the Ningbo First Hospital from June 2010 to June 2021 were examined.These patients were definitively diagnosed by pathological biopsy or immunohistochemical staining.The diagnostic criteria were based on the 2008 World Health Organization classification of lymphomas.Ann Arbor staging was performed according to the imaging and bone marrow examination results.Risk stratification of all patients was performed based on the International Prognostic Index(IPI),age-adjusted IPI,Follicular Lymphoma International Prognosis Index(FLIPI),and FLIPI2 to compare the efficacy of different treatment regimens and analyze the related prognostic factors.RESULTS The age of onset in patients ranged from 24 to 76 years,with a median age of 51 years.Most patients developed the disease at 40–59 years of age,and the male:female ratio was 1.6:1.No significant difference was noted in the curative effect between the non-chemotherapy,combined chemotherapy,and other chemotherapy regimens(P>0.05).Hemoglobin(Hb)level<120 g/L,Ki-67 value>50%,bone marrow involvement,and clinical stagesⅢ–IV were associated with a poor prognosis of FL(P<0.05).However,the influence of other indicators was not statistically significant.Risk grouping was performed using the FLIPI,and the results showed that 24.5%,40.8%,and 34.7%of patients were in the low-,moderate-,and high-risk groups,respectively.According to the survival analysis results,the survival rate of patients was lower in the high-risk group than in the other low-risk and moderate-risk groups(P<0.05).CONCLUSION FL mainly occurs in middle-aged and elderly men,primarily affecting lymph nodes and bone marrow.Hb level,Ki-67 value,bone marrow involvement,and clinical staging were used to evaluate prognosis.
基金Under the auspices of the National Natural Science Foundation of China (No. 40371030)
文摘Shift-share analysis has been confirmed a useful approach in the study of regional economics and many kinds of extended shift-share models have been advanced and put into practice in economic studies, but few have hitherto been introduced and applied to the tourism research in China. Moreover understanding the spatially competitive relationship is of paramount importance for marketers, developers, and planners involved in tourism strategy development. Based on international tourism receipts from 1995 to 2004, this study aims at probing into the spatial competitiveness of interna- tional tourism in Jiangsu Province in comparison with its neighbors by applying a spatially extended shift-share model and a modified dynamic shift-share model. The empirical results illustrate that exceptional years may exist in the ap- plication of dynamic shift-share models. To solve this issue, modifications to dynamic shift-share model are put forward. The analytical results are not only presented but also explained by the comparison of background conditions of tourism development between Jiangsu and its key competitors. The conclusions can be drawn that the growth of international tourism receipts in Jiangsu mainly attributes to the national component and the competitive component and Zhejiang is the most important rival to Jiangsu during the period of 1995-2004. In order to upgrade the tourism competitiveness, it is indispensable for Jiangsu to take proper positioning, promoting and marketing strategies and to cooperate and integrate with its main rivals.
基金Supported by National Soft Science Research Program(2009GXS5D120):Forecasting and Countermeasures against the Influence of Constructing Hainan International Tourism Island on Its Tourism Natural EnvironmentHainan Provincial Natural Science Foundation(70899):Influence of Constructing Hainan International Tourism Island on Its Tourism Natural Environment and Countermeasures+1 种基金Hainan Provincial Philosophical Social Science Planning(HNSK08-03):Relationship between Economic Growth and Ecological Environment of Hainan ProvinceHainan Provincial Educational Department Project(Hjkj2009-02):Influence of Constructing Hainan International Tourism Island on Its Natural Tourism Environment~~
文摘Investigation and analysis of natural tourism environment is the foundation and premise of tourism planning,development and management.Through investigating,classifying and evaluating natural tourism resources in Hainan according to the Classification,Investigation and Evaluation of Tourism Resources(GB/T18972-2003),it was found that there are 4 principal categories,6 sub-categories and 61 basic types of natural tourism resources,accounting for 100%,94.1% and 85.9% of the national total respectively.There are 335 natural tourism resource units in Hainan,47 of them are superfine ones accounting for 14.0% of the total,225 excellent ones accounting for 67.2% of the total,48 common ones accounting for 14.3% of the total,62 of them without acquiring any grade,that is,18.5% of the total.Most of these resources are located in the mountainous areas in the central island,eastern coastal areas and Sanya City.Meanwhile,through collecting and sorting out the environmental quality bulletins and statistics of Hainan in recent 5 years,quality changes of its natural tourism environment have been analyzed,and it was found that the quality of water,air and sound on the whole in this island is fine,but a few study cities(towns) are suffering from serious noise pollution.Thus,besides enjoying its generally excellent ecological environment,Hainan Island is still faced with serious challenges.
基金Supported by Ministry of Education,Science and Technological development,Republic of Serbia,2011-2020,No.175042.
文摘BACKGROUND Pancreatic cancer,as the one of most fatal malignancies,remains a critical issue in the global burden of disease.AIM To estimate trends in pancreatic cancer incidence and mortality worldwide in the last three decades.METHODS A descriptive epidemiological study was done.Pancreatic cancer incidence and mortality data were obtained from the database of the World Health Organization.Analysis of pancreatic cancer incidence and mortality during 2020 was performed.The age-standardized rates(ASRs,expressed per 100000)were presented.To estimate trends of incidence and mortality of pancreatic cancer,joinpoint regression analysis was used:the average annual percent change(AAPC)with the corresponding 95%confidence interval(95%CI)was calculated.Additionally,analysis was performed by sex and age.In this paper,the trend analysis included only countries with high and medium data quality.RESULTS A total of 495773(262865 male and 232908 female)new cases and 466003(246840 male and 219163 female)deaths from pancreatic cancer were reported worldwide in 2020.In both sexes,most of the new cases(191348;38.6%of the total)and deaths(182074;39.1%of the total)occurred in the Western Pacific Region.In both sexes,the highest ASRs were found in the European Region,while the lowest rates were reported in the South-East Asia Region.The general pattern of rising pancreatic cancer incidence and mortality was seen across countries worldwide in observed period.Out of all countries with an increase in pancreatic cancer incidence,females in France and India showed the most marked rise in incidence rates(AAPC=+3.9%and AAPC=+3.7%,respectively).Decreasing incidence trends for pancreatic cancer were observed in some countries,but without significance.Out of all countries with an increase in pancreatic cancer mortality rates,Turkmenistan showed the most marked rise both in males(AAPC=+10.0%,95%CI:7.4–12.5)and females(AAPC=+6.4%,95%CI:3.5–9.5).The mortality trends of pancreatic cancer were decreasing in both sexes only in Canada and Mexico.CONCLUSION Further research is needed to explain the cause of large international differences in incidence and mortality trends of pancreatic cancer in last three decades.
基金The authors gratefully acknowledge Universitàdegli studi della Campania“L.Vanvitelli”for funding the research project CHIMERA with V:ALERE 2019 grant。
文摘Waste heat recovery is one of the possible solutions to improve the efficiency of internal combustion engines.Instead of wasting the exhaust stream of an energy conversion system into the environment,its residual energy content can be usefully recovered,for example in Organic Rankine Cycles(ORC).This technology has been largely consolidated in stationary power plants but not yet for mobile applications,such as road transport,due to the limitations in the layout and to the constraints on the size and weight of the ORC system.An ORC system installed on the exhaust line of a bus powered by a natural gas spark ignition engine has been investigated.The thermal power available at engine exhaust has been evaluated by measuring gas temperature and mass flow rate during real driving operation.The waste thermal power has been considered as heat input for the ORC plant simulation.A detailed heat exchanger model has been developed because it is a crucial component for the ORC performance.The exergy analysis of the ORC was performed comparing different working fluids:R601,R1233zd(E)and two zeotropic blends of the two organic pure fluids.The model allowed the evaluation of the ORC produced energy over the driving cycle and the potential benefit on the engine efficiency.
基金Social Science Planning Project of Xi an City(JG140)Bidding Project of Buchang Xixian Economic Research Institute(SMZX202113).
文摘Based on the analysis of rice planting and export development in Heilongjiang Province in 2013-2021,this paper comprehensively used three export competitiveness analysis methods,namely,trade competitiveness index,revealed comparative advantage(RCA)analysis and international market share analysis,to compare the four major rice exporters in the world and the three major rice export provinces and cities in China.Besides,it evaluated the rice export competitiveness of Heilongjiang Province from multiple perspectives.It analyzed the reasons for low competitiveness in terms of export product structure,export market structure,production and processing technology,and brand building.Finally,it is recommended to clarify the positioning of rice export quality and take more measures to ensure product quality;improve the level of industrialization of rice production and processing,and extend the rice industry chain;develop diversified rice export markets and improve export flexibility;adhere to the principle of"opening the door and going out",expand the international popularity of high-quality brands,so as to enhance the rice export competitiveness of Heilongjiang Province.