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Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering
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作者 Xingjun Li Dan Yu +1 位作者 Søren Byg Vilsen Daniel Ioan Stroe 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期591-604,共14页
State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging pro... State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application. 展开更多
关键词 Feature engineering Dynamic forklift aging profile State of health comparison Machine learning Lithium-ion batteries
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Global Research Progress on Municipal Waste and Future Prospect Based on the Cross-national Comparisons
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作者 ZHANG Yuxin LIU Xiaoqian +2 位作者 YAN Xiaoxia MA Sike MAO Weiyun 《Chinese Geographical Science》 SCIE CSCD 2024年第2期250-264,共15页
Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an sustainability.To elucidate historical trends,current focal points,and future directions in MW ... Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an sustainability.To elucidate historical trends,current focal points,and future directions in MW research,we conducted a bibliometric analysis and employed knowledge graph visualization to scrutinize a total of 34212 articles,which were published between 1991 and 2021 in the Web of Science(WoS)core database.The results indicated that current major research themes encompass waste classifica-tion and recycling,waste management and public behavior,waste disposal methods and technologies,as well as environmental impact and evaluation.There has been a shift in the research focus from the environmental impacts of waste incineration to sustainable manage-ment related issues.A comparison of research from six typical countries revealed the differences in research priorities and techniques advantages.Scholars from the USA and Britain initiated MW research earlier than other countries and investigated management issues in depth,such as public behavior and willingness to pay.Meanwhile,Japanese,German,and Swedish scholars conducted extensive studies on advanced waste treatment technologies,such as disposal and recycling,risk assessment,and waste-to-energy techniques.Chinese scholars placed particular emphasis on end-of-pipe treatments and their associated environmental impacts.Hotspots and poten-tial future frontiers were identified by burst detection analysis.Keywords with high value of burst index(BI)worldwide are food waste and circular economy.Chinese scholars have put great efforts on waste environmental impact and its recycling technologies,while we’re expecting to further investigating vulnerable population.Furthermore,this study contributes to bridging the regional gap of scientific research among different countries and fostering international collaboration. 展开更多
关键词 BIBLIOMETRICS municipal waste(MW) CiteSpace hotspot prediction burst index(BI) SUSTAINABILITY cross-national comparison Web of Science(WoS)
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Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen
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作者 Troy Myers MichaelASutton +2 位作者 Hubert Schreier Alistair Tofts Sreehari Rajan Kattil 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第8期1263-1298,共36页
To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is... To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process. 展开更多
关键词 StereoDIC spatial co-registration data transformation finite element simulations point-wise comparison of measurements and FEA predictions double edge notch specimen model validation
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平“语”近人中课程思政元素comparison的应用及分析
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作者 武悦 《海外英语》 2023年第13期85-87,共3页
文章的研究目的是理解平“语”近人中comparison(比喻)的用法,平“语”近人中课程思政的内容和其背后的真实含义具有重要的教育意义。文章以话语中课程思政元素的comparison主要例子作为研究对象,来探讨和研究平“语”近人话语中的关于c... 文章的研究目的是理解平“语”近人中comparison(比喻)的用法,平“语”近人中课程思政的内容和其背后的真实含义具有重要的教育意义。文章以话语中课程思政元素的comparison主要例子作为研究对象,来探讨和研究平“语”近人话语中的关于comparison的应用并且加以分析。 展开更多
关键词 平“语”近人 课程思政元素 comparison应用分析
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First acceptance testing of multiple A10 absolute gravimeters in China and analysis of the comparison results 被引量:1
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作者 Xiaotong Zhang Hao Zhou +4 位作者 Ying Jiang Dulin Zhai Gongzhe Wei Hui Li Ziwei Liu 《Geodesy and Geodynamics》 EI CSCD 2023年第4期401-410,共10页
Three A10 absolute gravimeters(AGs) were first acquired in China by the Hubei Earthquake Agency under the Belt and Road Seismic Monitoring Network Project. Although AG measuring and testing technique is not new, the p... Three A10 absolute gravimeters(AGs) were first acquired in China by the Hubei Earthquake Agency under the Belt and Road Seismic Monitoring Network Project. Although AG measuring and testing technique is not new, the purchase and simultaneous testing of 3 A10 absolute gravimeters is unprecedented in China. This study conducted the first acceptance testing of the AGs at 3 locations(the Jiufengshan Gravity Observation Station, the Global Navigation Satellite System Observation Station in Wuhan, and the Jiugongshan Observation Station in Xianning). The results were compared using a method based on expert validation, and the acceptance testing scheme was formulated by referring to the Technical Regulations for Tectonic Environment Monitoring Networks in China and Specifications for Gravimetry Control. Based on the repeatability, precision, and consistency of the measured g values, the results from each instrument were evaluated using the air pressure precision test. Comparing the instrument reference values, the final test results can identify the indicator parameters for 3 A10 AGs, the effects of the surrounding environment, and the related parameters on measurement precision. The precision of A10-059, A10-058, and A10-057 exceeded 0.78 μGal, 0.79 μGal, and 0.42 μGal, respectively.This testing scheme can be used as a reference for conducting acceptance testing of AGs in the future and obtaining absolute gravimetric measurements. 展开更多
关键词 Gravitational acceleration comparison of absolute gravimeters A10 absolute gravimeters Instrument precision
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Multiomics comparison among populations of three plant sources of Amomi Fructus
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作者 Xinlian Chen Shichao Sun +15 位作者 Xiaoxu Han Cheng Li Fengjiao Wang Bao Nie Zhuangwei Hou Song Yang Jiaojiao Ji Ge Li Yanqian Wang Xiaoyu Han Jianjun Yue Cui Li Wei Li Lixia Zhang Depo Yang Li Wang 《Horticulture Research》 SCIE CSCD 2023年第8期129-142,共14页
Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV... Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV has been transplanted from its top-geoherb region,Guangdong,to its current main production area,Yunnan,for>50 years in China.However,the genetic and transcriptomic differentiation among multiple AF source species(or varieties)and between the origin and transplanted populations of WVV is unknown.In our study,the observed overall higher expression of terpenoid biosynthesis genes in WVV than in WVX provided possible evidence for the better pharmacological effect of WVV.We also screened six candidate borneol dehydrogenases(BDHs)that potentially catalyzed borneol into camphor in WVV and functionally verified them.Highly expressed genes at the P2 stage of WVV,Wv05G1424 and Wv05G1438,were capable of catalyzing the formation of camphor from(+)-borneol,(-)-borneol and DL-isoborneol.Moreover,the BDH genes may experience independent evolution after acquiring the ancestral copies,and the following tandem duplications might account for the abundant camphor content in WVV.Furthermore,four populations of WVV,WVX,and WL are genetically differentiated,and the gene flow from WVX to WVV in Yunnan contributed to the greater genetic diversity in the introduced population(WVV-JH)than in its top-geoherb region(WVV-YC),which showed the lowest genetic diversity and might undergo genetic degradation.In addition,terpene synthesis(TPS)and BDH genes were selected among populations of multiple AF source species(or varieties)and between the top-and non-top-geoherb regions,which might explain the difference in metabolites between these populations.Our findings provide important guidance for the conservation,genetic improvement,and industrial development of the three source species(or varieties)and for identifying top-geoherbalism with molecular markers,and proper clinical application of AF. 展开更多
关键词 HERBAL AMONG comparison
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Natural gas characteristics and gas-source comparisons of the Lower Triassic Feixianguan Formation,Eastern Sichuan Basin,China
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作者 Zi-Yun Zheng Yin-Hui Zuo +5 位作者 Hua-Guo Wen De-Ming Li Yang Luo Jia-Zhen Zhang Mei-Hua Yang Jian-Cheng Zeng 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1458-1470,共13页
There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Fe... There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Feixianguan Formation and thus hampers natural gas exploration in the region,so further study is urgently required.Using experimental tests of natural gas composition,stable isotopes,and noble gas isotopes with gas chromatography(GC)and mass spectrometry(MS)studies of source rock and reservoir asphalt saturated hydrocarbons,the natural gas geochemical characteristics,the genetic identification and a gas-source comparison of the Feixianguan Formation were studied.Then,con-strained by the thermal history,the histories of gas generation and expulsion were restored by basin simulation technology.Finally,a gas accumulation model was established for the Feixianguan Formation.The results showed that(1)the H_(2)S-rich and H2S-poor gas reservoirs of the Feixianguan Formation are distributed on the east and west sides of the Kaijiang-Liangping trough in the Eastern Sichuan Basin,respectively.The carbon and hydrogen isotope compositions of the natural gas in the gas reservoirs are generally heavy and have typical characteristics of high-maturity dry gas reservoirs.(2)The natural gas of the Feixianguan Formation is organic thermogenic gas,which is mainly oil-type gas generated by the secondary cracking of crude oil.The gas-generating parent material is mainly type II kerogen.(3)The natural gas of the Feixianguan Formation in the Eastern Sichuan Basin was mainly generated by argil-laceous source rocks of the Upper Permian Longtan Formation.(4)Natural gas accumulation occurred as follows:the paleo-structure heights were filled with crude oil in the Early Jurassic,and paleo-oil res-ervoirs were formed in the Feixianguan Formation;during the Middle-Late Jurassic,the paleo-oil res-ervoirs were cracked when the reservoir temperatures rose above 160 C,and paleo-gas reservoirs were formed.Since the end of the Late Jurassic,the paleo-gas reservoirs have been adjusted and reformed to form the present-day natural gas reservoirs.These results provide a basis for studying natural gas accumulation dynamics of the Feixianguan Formation in the Eastern Sichuan Basin. 展开更多
关键词 Eastern Sichuan Basin Feixianguan Formation Natural gas origin Gas-source comparison Longtan Formation
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An Effective Security Comparison Protocol in Cloud Computing
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作者 Yuling Chen Junhong Tao +2 位作者 Tao Li Jiangyuan Cai Xiaojun Ren 《Computers, Materials & Continua》 SCIE EI 2023年第6期5141-5158,共18页
With the development of cloud computing technology,more and more data owners upload their local data to the public cloud server for storage and calculation.While this can save customers’operating costs,it also poses ... With the development of cloud computing technology,more and more data owners upload their local data to the public cloud server for storage and calculation.While this can save customers’operating costs,it also poses privacy and security challenges.Such challenges can be solved using secure multi-party computation(SMPC),but this still exposes more security issues.In cloud computing using SMPC,clients need to process their data and submit the processed data to the cloud server,which then performs the calculation and returns the results to each client.Each client and server must be honest.If there is cooperation or dishonest behavior between clients,some clients may profit from it or even disclose the private data of other clients.This paper proposes the SMPC based on a Partially-Homomorphic Encryption(PHE)scheme in which an addition homomorphic encryption algorithm with a lower computational cost is used to ensure data comparability and Zero-Knowledge Proof(ZKP)is used to limit the client’s malicious behavior.In addition,the introduction of Oblivious Transfer(OT)technology also ensures that the semi-honest cloud server knows nothing about private data,so that the cloud server of this scheme can calculate the correct data in the case of malicious participant models and safely return the calculation results to each client.Finally,the security analysis shows that the scheme not only ensures the privacy of participants,but also ensures the fairness of the comparison protocol data. 展开更多
关键词 Secure comparison protocols zero-knowledge proof homomorphic encryption cloud computing
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A comparison study of prevalence,awareness,treatment and control rates of hypertension and associated factors among adults in China and the United States based on national survey data
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作者 Xiaomin Sun Xinguang Chen +10 位作者 Zumin Shi Alice Fang Yan Zhongying Li Shiqi Chen Bingtong Zhao Wen Peng Xi Li Mei Zhang Limin Wang Jing Wu Youfa Wang 《Global Health Journal》 2023年第1期24-33,共10页
Objective:This study compared the prevalence,awareness,treatment and control of hypertension and associated factors in China and the United States(US).Methods:Adult data from nationally representative samples were der... Objective:This study compared the prevalence,awareness,treatment and control of hypertension and associated factors in China and the United States(US).Methods:Adult data from nationally representative samples were derived from the Chronic Disease and Risk Factors Surveillance in 2010 and 2013 in China and the National Health and Nutrition Examination Survey in 2010 and 2013 in the US.Multivariable logistic and Poisson regression analysis were conducted to assess associations of the four outcomes with body weight status and behavioral factors.Results:Age-standardized prevalence rates of hypertension was 35.7%(95%confidence interval[CI]:35.4%to 36.1%)in 2010 and 29.8%(95%CI:29.4%to 30.2%)in 2013 in China,and 35.3%(95%CI:33.6%to 37.1%)in 2010 and 37.9%(95%CI:36.0%to 39.7%)in 2013 in the US.Among hypertensive participants,the age-standardized rates of treatment were 18.4%(95%CI:17.9%to 1&9%)in 2010 and 23.8%(95%CI:23.1%to 24.6%)in 2013 in China and 54.5%(95%CI:50.3%to 5&7%)in 2010 and 50.9%(95%CI:46.5%to 55.3%)in 2013 in the US;the age-standardized hypertension control rates were 3.2%(95%CI:3.0%to 3.5%)and 5.7%(95%CI:5.3%to 6.0%)in 2010 and 2013 in China and 50.6%(95%CI:46.2%to 55.0%)and 55.3%(95%CI:50.3%to 60.3%)in the US.Obesity was significantly associated with prevalence,awareness and control rates in both countries.Different from the US,obesity was negatively associated with hypertension control in China.Conclusion:Hypertension prevalence in China is similar to that in the US,but the control rate in China was significantly lower.Obesity was a critical risk factor for poor hypertension control in China. 展开更多
关键词 HYPERTENSION International comparison TREATMENT OBESITY Risk factors
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Typhoon Case Comparison Analysis Between Heterogeneous Many-Core and Homogenous Multicore Supercomputing Platforms
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作者 LIU Xin YU Xiaolin +5 位作者 ZHAO Haoran HAN Qiqi ZHANG Jie WANG Chengzhi MA Weiwei XU Da 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期324-334,共11页
In this paper,a typical experiment is carried out based on a high-resolution air-sea coupled model,namely,the coupled ocean-atmosphere-wave-sediment transport(COAWST)model,on both heterogeneous many-core(SW)and homoge... In this paper,a typical experiment is carried out based on a high-resolution air-sea coupled model,namely,the coupled ocean-atmosphere-wave-sediment transport(COAWST)model,on both heterogeneous many-core(SW)and homogenous multicore(Intel)supercomputing platforms.We construct a hindcast of Typhoon Lekima on both the SW and Intel platforms,compare the simulation results between these two platforms and compare the key elements of the atmospheric and ocean modules to reanalysis data.The comparative experiment in this typhoon case indicates that the domestic many-core computing platform and general cluster yield almost no differences in the simulated typhoon path and intensity,and the differences in surface pressure(PSFC)in the WRF model and sea surface temperature(SST)in the short-range forecast are very small,whereas a major difference can be identified at high latitudes after the first 10 days.Further heat budget analysis verifies that the differences in SST after 10 days are mainly caused by shortwave radiation variations,as influenced by subsequently generated typhoons in the system.These typhoons generated in the hindcast after the first 10 days attain obviously different trajectories between the two platforms. 展开更多
关键词 heterogeneous many-core supercomputing platform homogenous multicore supercomputing platform comparison analysis typhoon case
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A modified EDAS model for comparison of mobile wallet service providers in India
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作者 Sanjib Biswas Dragan Pamucar 《Financial Innovation》 2023年第1期1215-1245,共31页
The present paper has two-fold purposes.First,the current work provides an integrated theoretical framework to compare popular mobile wallet service providers based on users’views in the Indian context.To this end,we... The present paper has two-fold purposes.First,the current work provides an integrated theoretical framework to compare popular mobile wallet service providers based on users’views in the Indian context.To this end,we propose a new grey correlationbased Picture Fuzzy-Evaluation based on Distance from Average Solution(GCPF-EDAS)framework for the comparative analysis.We integrate the fundamental framework of the Technology Acceptance Model and Unified theory of acceptance and use of technology vis-a-vis service quality dimensions for criteria selection.For comparative ranking,we conduct our analysis under uncertain environments using picture fuzzy numbers.We find that user-friendliness,a wide variety of use,and familiarity and awareness about the products help reduce the uncertainty factors and obtain positive impressions from the users.It is seen that PhonePe(A3),Google Pay(A2),Amazon Pay(A4)and PayTM(A1)hold top positions.For validation of the result,we first compare the ranking provided by our proposed model with that derived by using picture fuzzy score based extensions of EDAS and another widely used algorithm such as The Technique for Order of Preference by Similarity to Ideal Solution.We observe a significant consistency.We then carry out rank reversal test for GCPF-EDAS model.We notice that our proposed GCPF-EDAS model does not suffers from rank reversal phenomenon.To examine the stability in the result for further validation,we carry out the sensitivity analysis by varying the differentiating coefficient and exchanging the criteria weights.We find that our proposed method provides stable result for the present case study and performs better as ranking order does not get changed significantly with the changes in the given conditions. 展开更多
关键词 Picture fuzzy Grey correlation EDAS method TOPSIS comparison of mobile wallets
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Social Comparison Orientation Associated with Psychological Well Being:The Mediated Role of Self-efficacy
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作者 QIU Yukai 《Psychology Research》 2023年第2期75-82,共8页
The paper focused on how social comparison orientation people apply influences their psychological well-being and how self-efficacy plays an important role in buffering some negative influence from upward social compa... The paper focused on how social comparison orientation people apply influences their psychological well-being and how self-efficacy plays an important role in buffering some negative influence from upward social comparison compared with someone better in one domain.In Festinger’s(1954)social comparison theory,the social comparison orientation instructed how people process the information they compared for,and related emotion was induced differently.In this paper,2,000 college students in Boston were proposed to participate in two experiments that discuss how different social comparison orientations affect their perception of life satisfaction.For the hypothetical result,we proposed that a high level of engagement in social comparison and ability-based social comparison was associated with less life satisfaction than the participants who had a low level of social comparison and opinion-based social comparison.In terms of coping strategy,we assumed that a high level of self-efficacy,which is the belief in capability to achieve a certain goal,will buffer the negative impact from upward comparison and improve the life satisfaction of those participants who like to engage with social comparison and ability-based comparison orientation. 展开更多
关键词 social comparison SELF-EFFICACY life satisfaction social media
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A Comparison of Different Values of Freedom Reflected in the Characters of Sun Wukong and Dean
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作者 HUANG Kaihong WEN Hui 《Sino-US English Teaching》 2023年第12期486-492,共7页
Both the characters of Sun Wukong in The Journey to the West,which is a traditional Chinese fiction,and Dean in On the Road,which is a typical American Beat Generation novel,have been pursuing a carefree lifestyle bas... Both the characters of Sun Wukong in The Journey to the West,which is a traditional Chinese fiction,and Dean in On the Road,which is a typical American Beat Generation novel,have been pursuing a carefree lifestyle based on their living environments respectively,but their values of freedom bear quite different meanings:Sun Wukong tries his best to struggle for a happy life for all his family and his friends as well as for himself with little consideration of the risk of his own life,while Dean is always on his way at random for his own personal happiness with little consideration for anybody else.Therefore,Sun Wukong’s behavior represents a kind of collectivism within his individualism,while Dean’s act reflects his American free life style of individualism to a certain extent. 展开更多
关键词 comparison COLLECTIVISM INDIVIDUALISM The Journey to the West On the Road
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Brain Abscess Surgery Outcome: A Comparison between Craniotomy with Membrane Excision versus Burr Hole Aspiration
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作者 Babiker Sirelkhatim Hassan Ali Abubakr Darrag Salim Ahmed +1 位作者 Mohammed Awad Elzain Fawaz Eljili Marhoom Abdelradi 《Open Journal of Modern Neurosurgery》 2023年第2期74-93,共20页
Introduction: Brain abscess represents 8% of intracranial masses in developing countries. Despite the advances in neuro-imaging, still, the diagnosis of brain abscess is difficult and may need a biopsy in most cases t... Introduction: Brain abscess represents 8% of intracranial masses in developing countries. Despite the advances in neuro-imaging, still, the diagnosis of brain abscess is difficult and may need a biopsy in most cases to verify the diagnosis because may even lead to death. CT scan with contrast is a good tool for diagnosing and localizing brain abscesses in late stages, however, it is difficult to diagnose them in the early stages. The development of MRI helps to more accurately diagnose brain abscess. Surgical management of brain abscesses is either medical or surgical through craniotomy or burr holes. Indications of each are still a point of debate among most neurosurgeons. Methodology: This is a descriptive longitudinal prospective study to compare the outcomes of two surgical procedures used in The National Centre for Neurological Sciences-Khartoum-Sudan (NCNS) from 2012 to 2015, craniotomy and excision of the abscess membrane versus burr hole and aspiration of brain abscess in terms of duration of hospitalization, length of antibiotic use, recurrence rate, number of images needed for follow-up, and the final postoperative early and late outcomes. The data was collected through a designed questionnaire and was then analyzed using SPSS version 20. No significant ethical approval was required for this study. Results: Fifty-four patients were operated on through craniotomy (29/54) and burr hole (25/54). Their ages ranged from 1 year to 53 years with an average presentation at 13 years of age. Most patients presented with fever (23.1%), convulsions (16%), vomiting (16.7%) and headache (15.4%). The mean of illness for both groups was almost 2 months. The majority of patients in this study were having no risk factors (38.9%) while the major risk factors seen were cardiac diseases (14.8%), neurosurgical procedures (13%) and otitis media (11.1%). As most patients presented late, the diagnosis of most was made using CT brain with contrast (83.3%). In most of the patients (85.2%) there were no organisms separated in the culture. 8/54 patients had positive cultures, 7/8 were bacterial and only one (1/8) was fungal. Most patients received antibiotics for 45 days postoperatively in both craniotomy and burr hole groups. When both groups were compared, those operated with craniotomy were found to have a relatively higher length of hospital stay, however, no significant difference was found between both groups. Also, it was found that those operated on with craniotomy had a high cure rate and less recurrence in comparison with burr hole group. Deterioration and death were significantly higher among craniotomy group. Only CT brain was used as the imaging modality of choice for follow-up in both groups for 4 months’ duration and it was noted that complete evacuation was significantly higher among craniotomy group while remnants were higher among burr hole group. Conclusion: Brain abscess is still a challenging condition for neurosurgeons in Sudan. The limited number of Sudanese neurosurgeons, neurosurgical centers and diagnostic facilities contributed to delay in diagnosing brain abscess in most patients. It is important to design a strict protocol and precautions for any neurosurgical operation or bedside procedure to prevent infection and subsequent brain abscess development. CT brain with contrast is a good imaging tool for assessing the size, site and stage of brain abscesses. No significant difference between craniotomy or burr hole for clearance from brain abscess in terms of antibiotic used or duration of hospital stay. However, burr hole aspiration is associated with higher rates of recurrences. On the other hand, craniotomy and excision have relatively higher neurologic morbidity postoperative with expectantly higher post-operative hospitalization but no differences in the final outcome. Therefore, the selection of surgical technique should be individualized in each case based on the abscess site size source patient fitness for surgery and neurosurgeon’s preference. 展开更多
关键词 Brain Abscess Surgery OUTCOME comparison of Surgery of Brain Abscess Craniotomy versus Burrhole
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不同比对方式下的洲际标准时间复现性能分析
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作者 许龙霞 刘娅 +2 位作者 陈瑞琼 赵志雄 孟令达 《仪器仪表学报》 EI CAS CSCD 北大核心 2024年第2期160-167,共8页
中国科学院国家授时中心研制的标准时间复现系统具备支持洲际用户对标准时间频率信号的需求。本文以位于欧洲白俄罗斯明斯克的复现终端为分析对象,分析了共视、全视不同比对方式对复现时频信号性能的影响。对于洲际范围的时间复现,复现... 中国科学院国家授时中心研制的标准时间复现系统具备支持洲际用户对标准时间频率信号的需求。本文以位于欧洲白俄罗斯明斯克的复现终端为分析对象,分析了共视、全视不同比对方式对复现时频信号性能的影响。对于洲际范围的时间复现,复现终端与参考端共同可视卫星数变少。单一卫星导航系统可利用的共视卫星数明显减少,GPS/BDS共视可明显增加可视卫星数量,提高共视时间比对精度,全视比对对两地共同可视卫星数没有要求。分析结果表明,单GPS全视比对就可以达到优于GPS/BDS的共视比对复现效果。受BDS卫星星间偏差的影响,基于单BDS全视比对的复现效果比GPS稍差,GPS/BDS全视比对效果略有改善。复现终端运行在GPS/BDS共视比对融合GPS全视比对模式复现的时频信号的性能最优,可以满足洲际范围内5 ns的时间同步要求,为后续洲际大尺度范围的标准时间复现终端的运行模式提供参考。 展开更多
关键词 共视时间比对 全视时间比对 标准时间复现 GPS BDS
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区块链产业发展:经济特性与中美路径差异 被引量:1
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作者 李三希 张明圣 刘希 《产业经济评论》 2024年第2期137-152,共16页
区块链具有去中心化、可追溯性两大核心特征和不可篡改、去信任化、信息透明、可匿名性四大衍生特征,并进一步引致出能够作用于经济领域的五大经济特性:减少信息不对称、降低组织的集中度、提供可置信的承诺、生成新的价值标的、减少交... 区块链具有去中心化、可追溯性两大核心特征和不可篡改、去信任化、信息透明、可匿名性四大衍生特征,并进一步引致出能够作用于经济领域的五大经济特性:减少信息不对称、降低组织的集中度、提供可置信的承诺、生成新的价值标的、减少交易成本。区块链是否能与产业良好融合是其能否有效发挥上述重要经济特性的一个重要因素。本文通过对中美区块链行业的对比分析发现,中国对于区块链的应用领域态度更为审慎,同时也具有更强的政策导向,主要应用领域为实体经济;而美国虽然对区块链的政策导向不如中国明显,但其在技术、人才培养等方面都具有显著优势,区块链应用规模在全球范围内处于绝对领先地位。总的来看,中国区块链产业发展面临审慎的金融政策与区块链特征不匹配、结合区块链与实体经济的配套设施相对缺失、区块链适用领域有待细化、区块链技术有待提升等问题。为进一步推动中国区块链产业发展,需要推动央行数字货币发展、加强数字化基础设施建设、针对性推动区块链行业发展、加强区块链技术基础研究。 展开更多
关键词 区块链 中美比较 数字经济
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可级联组网的无线时间比对系统设计
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作者 刘音华 张颖博 +1 位作者 刘娅 李孝辉 《电子测量技术》 北大核心 2024年第1期1-8,共8页
随着科技的发展,越来越多的场合需要实现多个终端间的纳秒量级高精度时间比对,例如现代化军事靶场、战场、雷达观测基地等。现阶段常用的纳秒量级多终端间的时间比对方法是导航卫星共视法,该方法需要搭建数据交换链路,应用的灵活性受限... 随着科技的发展,越来越多的场合需要实现多个终端间的纳秒量级高精度时间比对,例如现代化军事靶场、战场、雷达观测基地等。现阶段常用的纳秒量级多终端间的时间比对方法是导航卫星共视法,该方法需要搭建数据交换链路,应用的灵活性受限。本文基于无线伪随机码测距原理、双向时间比对原理和码分多址技术,设计出一套可以自适应组网的高精度时间比对系统,不需要额外搭建数据交互通路即可实现级联节点之间的纳秒量级时间比对。其次,分析了利用该系统实现纳秒量级时间比对的技术难点,并提出了相应的解决方法。最后,搭建实验平台对设计的时间比对系统进行验证。实验结果表明,在500 m的无线比对基线下,可以实现优于0.5 ns的静态时间比对精度。 展开更多
关键词 时间比对 级联组网 双向比对 伪码测距 通道时延校准
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中、美、日、韩新能源汽车产业竞争优势测度与比较研究——以锂电池汽车为例 被引量:1
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作者 杨武 宋晓晴 《中国科技论坛》 北大核心 2024年第2期180-188,共9页
本文基于中、美、日、韩近30年在锂电池汽车领域的专利数据,选取20个关键指标构建“技术-经济-法律”三维分析模型,并划分出关键核心专利,在此基础上应用景气综合指数法计算四国在锂电池汽车产业的竞争优势指数,并对其进行比较与分析。... 本文基于中、美、日、韩近30年在锂电池汽车领域的专利数据,选取20个关键指标构建“技术-经济-法律”三维分析模型,并划分出关键核心专利,在此基础上应用景气综合指数法计算四国在锂电池汽车产业的竞争优势指数,并对其进行比较与分析。结果表明,中、美、日、韩在锂电池汽车领域的总体发展布局已基本到达顶峰,且于近两年呈现波动下降趋势。总体来看,美国获得竞争优势时间最早且指数发展趋势最为稳定,连续多年稳居第一;中国获得竞争优势时间最晚,但指数发展速度最快,截至2021年末,中国总体竞争优势指数与美国持平,远超日、韩两国。分维度来看,中、美分别于经济、技术维度具有绝对竞争优势;韩国在经济、法律维度发展较为稳定,但技术维度影响整体,导致整体呈现波动下降趋势;日本在各维度均呈现出明显下降趋势,仅在技术维度下降幅度较小。由此得出结论:中国经济发展带动整体,已基本实现锂电池汽车产业的技术赶超,技术维度的发展是获得持续性竞争优势的基础,因此应在保持现有锂电池汽车领域竞争优势的同时注重相关技术轨道的跨越与变迁,以获取新能源汽车产业的持续性竞争优势。 展开更多
关键词 新能源汽车 锂电池 竞争优势 测度与比较 关键核心专利
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国内外碳化硅标准比对分析
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作者 李景 黄佳 +1 位作者 李国鹏 孙红军 《标准科学》 2024年第1期101-113,共13页
为了探明碳化硅国内外标准的情况和差异,本文调研、分析并选择了中国国家标准和行业标准、国际标准及美国、欧洲、日本、俄罗斯、罗马尼亚相关标准,选择碳化硅物理特性、碳化硅磨料化学分析方法、含碳化硅耐火材料化学分析方法、碳化硅... 为了探明碳化硅国内外标准的情况和差异,本文调研、分析并选择了中国国家标准和行业标准、国际标准及美国、欧洲、日本、俄罗斯、罗马尼亚相关标准,选择碳化硅物理特性、碳化硅磨料化学分析方法、含碳化硅耐火材料化学分析方法、碳化硅晶片产品规格进行标准比对。通过比对,得出结论:(1)国外有关碳化硅标准,都制定了碳化硅产品的理化性能标准,有些指标我国国家标准和部分企业实际质量控制中未列入检测控制指标,如:振实密度、比表面积、清洁度、韧性、电导率;(2)针对碳化硅粒度砂与微粉产品,发达国家根据其用途不同,按照对口专用、精密化、综合利用原则,分成了多种牌号专用产品,专用产品的企业标准指标要求也不同,使生产者和使用者找到了最佳结合点,产品产生了最大效益;(3)从碳化硅磨料的化学分析方法标准比对和含碳化硅耐火材料化学分析方法标准比对结果看,我国国家标准的比对指标相较于美国、欧盟及日本等发达国家及地区而言较为完整;(4)从碳化硅晶片产品相关标准比对结果看,我国国家标准对碳化硅单晶抛光片以及晶片检测方面制定了相关标准,而美国、欧盟、日本等发达国家及地区没有涉及。针对碳化硅外延片表面缺陷的测试环境,我国国家标准相较于欧盟以及日本标准要求更高。 展开更多
关键词 碳化硅 标准 标准比对 中国国家标准(GB)
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四款主流语料对齐工具性能对比探析 被引量:1
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作者 王琴 王宇春 《南阳理工学院学报》 2024年第1期45-52,共8页
利用实验研究的方法,以科技、旅游、文学、政治四种中英双语文本为样本,对四款语料对齐工具进行了对比研究。研究发现,从基础技术指标来看,Matecat Aligner、ABBYY Aligner 2.0、Tmxmall Aligner更有优势;从非基础技术指标来看,Matecat ... 利用实验研究的方法,以科技、旅游、文学、政治四种中英双语文本为样本,对四款语料对齐工具进行了对比研究。研究发现,从基础技术指标来看,Matecat Aligner、ABBYY Aligner 2.0、Tmxmall Aligner更有优势;从非基础技术指标来看,Matecat Aligner和DéjàVu X3 Alignment在断句准确率方面更为突出,ABBYY Aligner 2.0在对齐准确率方面要优于其他工具;ABBYY Aligner 2.0和Matecat Aligner具有纠错功能。通过具体分析发现,使用不同类型的文本,对齐质量也有所不同;不同的语料对齐工具适合不同文本的对齐。 展开更多
关键词 语料对齐工具 性能对比 评价
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