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Long-term operation optimization of circulating cooling water systems under fouling conditions
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作者 Jiarui Liang Yong Tian +3 位作者 Shutong Yang Yong Wang Ruiqi Yin Yufei Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第1期255-267,共13页
Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optim... Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering fouling.However,low flow velocity promotes fouling.Therefore,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation.This study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this goal.The model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and fouling.By optimizing the concentration cycle of the CCWS,water conservation and fouling control can be achieved.The model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance coefficient.Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation decrease.In periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate.Overall,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization. 展开更多
关键词 Computer simulation Circulating water system FOULING Concentration cycle OPTIMIZATION Variable frequency drive
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The tri-band high spectral resolution spectrometer with gratings in tandem for the charge-exchange recombination spectroscopy diagnostic system on HL-2A tokamak
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作者 刘亮 余德良 +11 位作者 马倩 何小斐 Maarten DE BOCK Manfred von HELLERMANN Michael WALSH 陈文锦 何小雪 魏彦玲 张能 李栋 魏会领 the HL-2A Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第6期103-110,共8页
Charge-exchange(CX) recombination spectroscopy is a powerful tool monitoring ion temperature and plasma rotation with good temporal and spatial resolutions. A compact, new design for a high-throughput, tri-band high s... Charge-exchange(CX) recombination spectroscopy is a powerful tool monitoring ion temperature and plasma rotation with good temporal and spatial resolutions. A compact, new design for a high-throughput, tri-band high spectral resolution spectrometer has been developed for the charge-exchange recombination spectroscopy measurement on the HL-2A tokamak. The simultaneous measurements of He II(468.57 nm), C VI(529.1 nm), and Dα(656.1 nm accompanied by beam emission spectra) with an acquisition frequency up to 400 Hz are achieved by vertically binning the spectrum from each fiber in experiments. Initial results indicate that the system can provide radial profiles of not only ion temperature and rotation velocity,but also concentration of carbon. For the case of helium, the measurements for the ion temperature and rotation velocity are straightforward but the apparent concentration associated with the observed CX intensity is obviously too high. Modeling of the active He II CX feature including plume contributions needs to be carried out to extract the true helium concentration.The spectrometer could become a prototype for the ITER charge-exchange recombination spectroscopy diagnostic and the pilot experiments, as presented here, demonstrate the possibility of impurity concentrations measurements based on the combined measurement of local beam emission and charge-exchange recombination spectroscopy spectra. 展开更多
关键词 CXRS ion temperature plasma rotation impurity concentration
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Different concentrations of hyaluronic acid eye drops for dry eye syndrome: a systematic review and Meta-analysis
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作者 Xiao-Wei Ouyang Sheng Fang +5 位作者 Yun-Min Yi Shi-Peng Zou Qi-Yu Hu Zi-Xuan Huang Qing-Xia Li Jin-Yan Luo 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第6期1110-1119,共10页
AIM:To compare high or low concentration of hyaluronic acid eye drops(HY)for dry eye syndromes(DES).METHODS:Randomized controlled trials(RCTs)comparing various concentrations of HY were searched in PubMed,Embase,Web o... AIM:To compare high or low concentration of hyaluronic acid eye drops(HY)for dry eye syndromes(DES).METHODS:Randomized controlled trials(RCTs)comparing various concentrations of HY were searched in PubMed,Embase,Web of Science,Cochrane,SinoMed,CNKI,Wanfang Database,CQVIP,and Chinese journals databases between inception and July 2023.Pooled standardized mean differences(SMD)or weighted mean difference(WMD)with 95%confidence intervals(CI)from RCTs evaluating Schirmer’s I test(SIT),corneal fluorescein staining score(CFS),tear breakup time(TBUT),DES score(DESS),and Ocular Surface Disease Index(OSDI)were calculated.Sensitivity analysis,Egger’s test and Meta-regression analysis were performed for all indicators.RESULTS:We conducted a Meta-analysis of 10 RCTs that met the inclusion criteria,involving 1796 cases.High-concentrations group significantly improved the outcome of CFS according to random effects modelling(SMD,-3.37;95%CI,-5.25 to-1.48;P=0.0005).The rest of the results were not statistically significant,including indicators such as SIT,TBUT,DESS and OSDI.CONCLUSION:For dry eyes with positive corneal staining,a high concentration of HY is recommended,whereas in other cases,a high concentration of HY does not offer a more pronounced advantage over a low concentration of HY in the treatment of dry eyes. 展开更多
关键词 dry eye hyaluronic acid CONCENTRATION META-ANALYSIS
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Analysis of Air Exchange System Influence on Thermal and Concentration Modes in the Local Working Area under Radiant Heating Conditions
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作者 Boris Borisov Geniy Kuznetsov +2 位作者 Vyacheslav Maksimov Tatiana Nagornova Felix Salikhov 《Frontiers in Heat and Mass Transfer》 EI 2024年第6期1597-1612,共16页
One of the effective options for energy saving in terms of heat costs for the formation of routine thermal conditions of working areas of large-sized industrial premises is the replacement of traditional convective(wa... One of the effective options for energy saving in terms of heat costs for the formation of routine thermal conditions of working areas of large-sized industrial premises is the replacement of traditional convective(water)heating systems with systems,the main part of which are gas infrared emitters.But the mass introduction of such systems based on emitters was held back until recently by the lack of scientific and technical foundations for ensuring not only the routine thermal conditions of local working areas,but also ensuring acceptable concentrations of carbon dioxide,which is formed during the operation of a gas emitter.Solving the latter problem by the method of experimental selection of heating and air exchange modes is practically impossible due to the multivariate nature of possible solutions to this problem.Therefore,the purpose of the work is to analyze the results of theoretical studies of the possibility of ensuring an acceptable level of carbon dioxide concentrations in local working areas during the operation of gas infrared emitters and an air exchange system.Numerical modeling of heat and mass transfer processes under such conditions was performed in a fairly wide range of the main significant factors:air flow rate in the air exchange system from 0.01 to 0.04 kg/s,the position of the air inlet and outlet channels relative to the radiator and the local workplace(height from 0.3 to 4.1 m).It was found that by varying the numerical values of these factors,it is possible to ensure carbon dioxide concentrations in the local working area within the permissible limits of up to 1400 ppm. 展开更多
关键词 Gas infrared heater air exchange system local working areas temperature fields CO2 concentration fields
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Numerical Assessment of the Thermal Efficiency of a Concentrated Photovoltaic/Thermal (CPV/T) Hybrid System Using Air as Heat Transfer Fluid
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作者 Amadou Konfe Boureima Kabore +2 位作者 Yves Christian Nonguierma Fatimata Ouedraogo Sié Kam 《Smart Grid and Renewable Energy》 2024年第1期1-14,共14页
In this paper, we propose a thermal model of a hybrid photovoltaic/thermal concentration system. Starting from the thermal balance of the model, the equation is solved and simulated with a MATLAB code, considering air... In this paper, we propose a thermal model of a hybrid photovoltaic/thermal concentration system. Starting from the thermal balance of the model, the equation is solved and simulated with a MATLAB code, considering air as the cooling fluid. This enabled us to evaluate some of the parameters influencing the electrical and thermal performance of this device. The results showed that the temperature, thermal efficiency and electrical efficiency delivered depend on the air mass flow rate. The electrical and thermal efficiencies for different values of air mass flow are encouraging, and demonstrate the benefits of cooling photovoltaic cells. The results show that thermal efficiency decreases air flow rate greater than 0.7 kg/s, whatever the value of the light concentration used. The thermal efficiency of the solar cell increases as the light concentration increases, whatever the air flow rate used. For a concentration equal to 30 sun, the thermal efficiency is 0.16 with an air flow rate equal to 0.005 kg/s;the thermal efficiency increases to 0.19 with an air flow rate equal to 0.1 kg/s at the same concentration. An interesting and useful finding was that the proposed numerical model allows the determination of the electrical as well as thermal efficiency of the hybrid CPV/T with air flow as cooling fluid. 展开更多
关键词 PV Cell CONCENTRATING THERMAL Energy Conversion COOLING Hybrid system
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Microplastic Impacts on Greenhouse Gases Emissions in Terrestrial Ecosystems
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作者 Tazeen Fatima Khan M. M. Golam Rabbani 《Open Journal of Soil Science》 2024年第1期64-80,共17页
Microplastics can influence global climate change by regulating the emissions of greenhouse gases from different ecosystems. The effects of microplastics in terrestrial ecosystems are still not well studied particular... Microplastics can influence global climate change by regulating the emissions of greenhouse gases from different ecosystems. The effects of microplastics in terrestrial ecosystems are still not well studied particularly greenhouse gases emissions. Thus, we conducted a laboratory experiment over a period of 90 days with two types of microplastics (differing in their chemical structure), high density polyethylene (HDPE) and low density polyethylene (LDPE), which were applied to the soil at a rate of 0% to 0.1% (w/w). The overarching aim was to investigate the effects of microplastic type, microplastic concentration and days of exposure on greenhouse gases emissions. We also used original and artificially weathered microplastics (the same HDPE and LDPE) to make a comparison of greenhouse gases emissions between the original microplastics treated soils and the soils treated with weathered microplastics. Our findings showed that HDPE and LDPE microplastics significantly increased the emissions of greenhouse gases from the soil than that of the control soils. Emissions were increased with the increases in the level of microplastic in the soil. The weathered microplastic emitted greater quantity of greenhouse gases compared to that of the original microplastics. In contrast to a low initial emission quantity, the emissions were gradually increased at the termination of the experiment. Our experiment on the emissions of greenhouse gases from the soil vis-à-vis microplastic additions indicated that the microplastic increased the emissions of greenhouse gases in terrestrial ecosystems, and pervasive microplastic impacts may have consequences for the global climate change. Greenhouse gases emissions from the soil not only depend on the type and concentration of the microplastic, but also on the days of exposure to the microplastic. 展开更多
关键词 Microplastic Climate Change Greenhouse Gas TYPE CONCENTRATION
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Practice and analysis of recycling non-drinking water from air-condition and reverse-osmosis system into rainwater collection system 被引量:2
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作者 王小红 邵煜然 王靖华 《Journal of Southeast University(English Edition)》 EI CAS 2014年第2期169-174,共6页
This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilizat... This paper is based on the rainwater collection project in the retrofit of the Dongyi teaching block in Zhejiang University Xixi Campus.The analysis incorporates the local meteorological data, recycling water utilization, and precipitation adjustment.The rainwater collection system in this program also adds the condensation water from the heating, ventilation and air conditioning ( HVAC) system and the concentration from the reverse-osmosis system used for watering greens and supplying waterscapes.By calculating, the quantity of the HVAC condensation water in summer is 3.48 m3/d, and the quantity of the reverse-osmosis concentrated water is 198 to 396 L/d.This method solves the water shortage caused by high evaporation in summer and low precipitation in winter.Supported by empirical monitoring data, the proposed method significantly increases the economic efficiency of the system during the summer period. 展开更多
关键词 rainwater collection heating ventilation and air conditioning condensation water precipitation analysis reverse-osmosis concentrated water
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Responses of soil enzymes to long-term CO_2 enrichment in forest ecosystems of Changbai Mountains
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作者 辛丽花 韩士杰 +2 位作者 李莉 周玉梅 郑俊强 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第2期119-122,共4页
A study was conducted to determine the responses of soil enzymes (invertase, polyphenol oxidase, catalase, and dehydrogenase) to long-term CO2 enrichment at the Research Station of Changbai Mountain Forest Ecosystem... A study was conducted to determine the responses of soil enzymes (invertase, polyphenol oxidase, catalase, and dehydrogenase) to long-term CO2 enrichment at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences (42°24'N, 128°28'E; 738 m in elevation) in the northeast China during 1999-2006. Three treatments of the CO2 enrichment, designed as 500 μmol·mol-1 CO2 open-top chamber (OTC), ambient control chamber and unchambered field (approx. 370 μmol·mol^-1CO2), were conducted with Pinus koraiensis and Pinus sylvestriformis tree species. Soil sampling was made and analyzed separately in spring, summer and autumn in 2006 after the soil enzymes were exposed to elevated CO2 concentration (500 μmol·mol^-1) for eight growing seasons. Results showed that, at elevated CO2 concentration (500 μmol·mol^-1), the activities of invertase (except for the summer samples of P. koraiensis) presented a remarkable decline in all growing seasons, while the activities of dehydrogenase had an increase but only part of the results was remarkable; the activities of polyphenol oxidase in P. sylvestriformis rhizosphere showed a remarkable decrease; the catalase activities increased in spring, while in turn were decline in other seasons. This study also revealed that the soil enzyme activities are significantly correlated with the tree species under the CO2 enhancement. 展开更多
关键词 CO2 concentration CO2 enrichment Soil enzymes INVERTASE DEHYDROGENASE CATALASE Polyphenol oxidase
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Potassium and calcium channels in different nerve cells act as therapeutic targets in neurological disorders
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作者 Qing Qiu Mengting Yang +2 位作者 Danfeng Gong Haiying Liang Tingting Chen 《Neural Regeneration Research》 SCIE CAS 2025年第5期1258-1276,共19页
The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central n... The central nervous system, information integration center of the body, is mainly composed of neurons and glial cells. The neuron is one of the most basic and important structural and functional units of the central nervous system, with sensory stimulation and excitation conduction functions. Astrocytes and microglia belong to the glial cell family, which is the main source of cytokines and represents the main defense system of the central nervous system. Nerve cells undergo neurotransmission or gliotransmission, which regulates neuronal activity via the ion channels, receptors, or transporters expressed on nerve cell membranes. Ion channels, composed of large transmembrane proteins, play crucial roles in maintaining nerve cell homeostasis. These channels are also important for control of the membrane potential and in the secretion of neurotransmitters. A variety of cellular functions and life activities, including functional regulation of the central nervous system, the generation and conduction of nerve excitation, the occurrence of receptor potential, heart pulsation, smooth muscle peristalsis, skeletal muscle contraction, and hormone secretion, are closely related to ion channels associated with passive transmembrane transport. Two types of ion channels in the central nervous system, potassium channels and calcium channels, are closely related to various neurological disorders, including Alzheimer's disease, Parkinson's disease, and epilepsy. Accordingly, various drugs that can affect these ion channels have been explored deeply to provide new directions for the treatment of these neurological disorders. In this review, we focus on the functions of potassium and calcium ion channels in different nerve cells and their involvement in neurological disorders such as Parkinson's disease, Alzheimer's disease, depression, epilepsy, autism, and rare disorders. We also describe several clinical drugs that target potassium or calcium channels in nerve cells and could be used to treat these disorders. We concluded that there are few clinical drugs that can improve the pathology these diseases by acting on potassium or calcium ions. Although a few novel ion-channelspecific modulators have been discovered, meaningful therapies have largely not yet been realized. The lack of target-specific drugs, their requirement to cross the blood–brain barrier, and their exact underlying mechanisms all need further attention. This review aims to explain the urgent problems that need research progress and provide comprehensive information aiming to arouse the research community's interest in the development of ion channel-targeting drugs and the identification of new therapeutic targets for that can increase the cure rate of nervous system diseases and reduce the occurrence of adverse reactions in other systems. 展开更多
关键词 ASTROCYTES calcium channels central nervous system extracellular ion concentration MICROGLIA neurological disorders NEURONS potassium channels
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Vedolizumab serum trough concentrations with and without thiopurines in ulcerative colitis: The prospective VIEWS pharmacokinetics study
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作者 Thanaboon Chaemsupaphan Aviv Pudipeddi +4 位作者 Hui-Yu Lin Sudarshan Paramsothy Viraj C Kariyawasam Melissa Kermeen Rupert W Leong 《World Journal of Gastroenterology》 SCIE CAS 2025年第2期102-112,共11页
BACKGROUND Ulcerative colitis(UC)is a chronic inflammatory condition requiring continuous treatment and monitoring.There is limited pharmacokinetic data on vedolizumab during maintenance therapy and the effect of thio... BACKGROUND Ulcerative colitis(UC)is a chronic inflammatory condition requiring continuous treatment and monitoring.There is limited pharmacokinetic data on vedolizumab during maintenance therapy and the effect of thiopurines on vedolizumab trough concentrations is unknown.AIM To investigate the exposure-response relationship of vedolizumab and the impact of thiopurine withdrawal in UC patients who have achieved sustained clinical and endoscopic remission during maintenance therapy.METHODS This is a post-hoc analysis of prospective randomized clinical trial(VIEWS)involving UC patients across 8 centers in Australia from 2018 to 2022.Patients in clinical and endoscopic remission were randomized to continue or withdraw thiopurine while receiving vedolizumab.We evaluated vedolizumab serum trough concentrations,presence of anti-vedolizumab antibodies,and clinical outcomes over 48 weeks to assess exposure-response asso-ciation and impact of thiopurine withdrawal.RESULTS There were 62 UC participants with mean age of 43.4 years and 42%were females.All participants received vedolizumab as maintenance therapy with 67.7%withdrew thiopurine.Vedolizumab serum trough concentrations remained stable over 48 weeks regardless of thiopurine use,with no anti-vedolizumab antibodies detected.Pa-tients with clinical remission had higher trough concentrations at week 48.In quartile analysis,a threshold of>11.3μg/mL was associated with sustained clinical remission,showing a sensitivity of 82.4%,specificity of 60.0%,and an area of receiver operating characteristic of 0.71(95%CI:0.49-0.93).Patients discontinuing thiopurine required higher vedolizumab concentrations for achieving remission.CONCLUSION A positive exposure-response relationship between vedolizumab trough concentrations and UC outcomes suggests that monitoring drug levels may be beneficial.While thiopurine did not influence vedolizumab levels,its with-drawal may necessitate higher vedolizumab trough concentrations to maintain remission. 展开更多
关键词 PHARMACOKINETIC Vedolizumab THIOPURINE Ulcerative colitis Trough concentration Antibody Inflammatory bowel diseases
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Impact of Pollutant Concentration and Particle Deposition on the Radiative Flow of Casson-Micropolar Fluid between Parallel Plates
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作者 Ghaliah Alhamzi Badr Saad T.Alkahtani +2 位作者 Ravi Shanker Dubey Vinutha Kalleshachar Neelima Nizampatnam 《Computer Modeling in Engineering & Sciences》 SCIE EI 2025年第1期665-690,共26页
Assessing the behaviour and concentration of waste pollutants deposited between two parallel plates is essential for effective environmental management.Determining the effectiveness of treatment methods in reducing po... Assessing the behaviour and concentration of waste pollutants deposited between two parallel plates is essential for effective environmental management.Determining the effectiveness of treatment methods in reducing pollution scales is made easier by analysing waste discharge concentrations.The waste discharge concentration analysis is useful for assessing how effectively wastewater treatment techniques reduce pollution levels.This study aims to explore the Casson micropolar fluid flow through two parallel plates with the influence of pollutant concentration and thermophoretic particle deposition.To explore the mass and heat transport features,thermophoretic particle deposition and thermal radiation are considered.The governing equations are transformed into ordinary differential equations with the help of suitable similarity transformations.The Runge-Kutta-Fehlberg’s fourthfifth order technique and shooting procedure are used to solve the reduced set of equations and boundary conditions.The integration of a neural network model based on the Levenberg-Marquardt algorithm serves to improve the accuracy of predictions and optimize the analysis of parameters.Graphical outcomes are displayed to analyze the characteristics of the relevant dimensionless parameters in the current problem.Results reveal that concentration upsurges as the micropolar parameter increases.The concentration reduces with an upsurge in the thermophoretic parameter.An upsurge in the external pollutant source variation and the local pollutant external source parameters enhances mass transport.The surface drag force declines for improved values of porosity and micropolar parameters. 展开更多
关键词 Micropolar fluid thermal radiation porous medium thermophoretic particle deposition waste discharge concentration
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Strength of circular concrete columns under concentric compression
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作者 赵玲 李爱群 《Journal of Southeast University(English Edition)》 EI CAS 2003年第1期74-78,共5页
An experimental study, in which six columns were loaded concentrically toinvestigate the behavior of reinforced normal strength and high strength circular columns underconcentric compression, is described. The concret... An experimental study, in which six columns were loaded concentrically toinvestigate the behavior of reinforced normal strength and high strength circular columns underconcentric compression, is described. The concrete strengths of the columns were 30 MPa and 60 MPa.The primary variables considered were the concrete strength and the amount of transversereinforcement. Test results indicate that smaller hoop spacing provides higher column capacity andgreater strength enhancement in a confined concrete core of columns. For the same lateralconfinement, high strength concrete columns develop lower strength enhancement than normal strengthconcrete columns. Both the strength enhancement ratio (f'_(cc) /f'_(co)) and the column capacityratio (P_(test)/P_o) were observed to show linear increase variations with rho_s f_(yt)/f'_c incircular columns. 展开更多
关键词 COLUMNS high strength concrete hoop spacing concentric loading
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Design of Reflective Concentrator Model with Application for Concentrator Photovoltaic System 被引量:8
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作者 SU Zhongyuan ZHANG Yaoming +3 位作者 JIA Minping SUN Liguo XU Feiyun WANG Jun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第6期1007-1012,共6页
The nonuniform irradiation in the standard photovoltaic(PV) cells causes their relatively high series resistance,which results in a considerably lowered efficiency of PV cells.Currently the concentrator of uniform i... The nonuniform irradiation in the standard photovoltaic(PV) cells causes their relatively high series resistance,which results in a considerably lowered efficiency of PV cells.Currently the concentrator of uniform irradiation designed for concentrator photovoltaic is rare in China and lack sufficient theoretical research.In this paper,a systematic research on the solar reflective concentrator is conducted.A novel structure for a solar reflective concentrator is designed with the application of a flat mirror matrix to concentrate the sunlight for concentrator photovoltaic(CPV) systems.Sunlight beams are focused through the reflection of the mirror array on the solar cell to generate electricity.The concentrator is capable of producing much more uniform sunlight with a certain concentration ratio.The design scheme includes laying out the flat mirrors,optimizing the optical pathway and the parameters of each mirror.The prototype of the CPV system was installed at Nanjing,China.In the configuration of the prototype,it is composed of 24 pieces parallelogram flat mirrors,which are arranged into a total reflective array of 5 rows and 5 columns.In comparison with the parabolic trough concentrator,the experimental measurements verify such design has high efficiency.The concentrator model of a flat mirror matrix and the proposed new design method will lay a solid foundation for designing the concentrator of uniform irradiation. 展开更多
关键词 CONCENTRATOR uniform concentration concentrator photovoltaic sun tracking
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Changes of nutrient concentrations and N:P:Si ratios and their possible impacts on the Huanghai Sea ecosystem 被引量:16
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作者 FU Mingzhu WANG Zongling +2 位作者 PU Xinming XU Zongjun ZHU Mingyuan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2012年第4期101-112,共12页
To investigate the impacts of nutrient concentrations and N:P:Si ratios on the ecosystem of the Huanghai Sea (Yellow Sea), the current status and long-term variation of nutrients concentrations and ratios as well ... To investigate the impacts of nutrient concentrations and N:P:Si ratios on the ecosystem of the Huanghai Sea (Yellow Sea), the current status and long-term variation of nutrients concentrations and ratios as well as phytoplankton community structure in the Huanghai Sea were collected and analyzed. The results reveal great annual and seasonal fluctuations in the nutrient concentrations and N:P:Si ratios during 1998-2008 with no clear pattern observed in the whole region. Yet on a seasonal scale of spring and in the coastal regions such as the Jiaozhou Bay and Sanggou Bay, the increase of DIN concentration and N:P ratio as well as the decrease of phosphate and sili- cate concentrations and Si:N ratios were relatively significant. Many pelagic ecosystem changes have occurred concurrent with these changes of the nutrient regime, such as the recent increase of primary production, changes of phytoplankton chlorophyll a biomass and abundance, an increase of eutrophication, and occurrence of HABs. In addition, new trends in the variation of nutrients seem to be developing in some particular transect such as 36N, which suggests that long-term and systematic ecosystem monitoring in the Huanghai Sea is necessary. 展开更多
关键词 nutrient concentration and ratio long-term variation Huanghai Sea ecosystemresponse
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Numerical investigation of laminar heat transfer and nanofluid flow between two porous horizontal concentric cylinders 被引量:8
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作者 Mehdi MIRZAEYAN Davood TOGHRAIE 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第7期1976-1999,共24页
In this study, the laminar heat transfer and nanofluid flow between two porous horizontal concentric cylinders was investigated. The problem is investigated in two different geometries and the Re=10, 25, 50, 75, 100 a... In this study, the laminar heat transfer and nanofluid flow between two porous horizontal concentric cylinders was investigated. The problem is investigated in two different geometries and the Re=10, 25, 50, 75, 100 and volume fraction 0, 0.2%, 0.5%, 2% and 5% that related to copper nanoparticles, and porous medium porosity of 0.5 and 0.9. Compared to the first geometry, the convective coefficient in the second geometry increases by 8.3%, 7% and 5.5% at Reynolds numbers of 100, 75 and 50, respectively. Comparison of the outlet temperatures for two heat fluxes of 300 and 1200 W/m^2 indicates a 2.5% temperature growth by a fourfold increase in the heat fluxes. Also, the higher Nusselt number is associated with the second geometry occurring at porosities of 0.9 and 0.5, respectively. In both geometries, the Nusselt number values at the porosity of 0.9 are higher, which is due to the increased nanofluid convection at higher porosities. The velocity of the nanofluid experiences a two-fold increase at the outlet compared to its inlet velocity in the first geometry and for both porosities. Similarly, a three-fold increase was achieved in the second geometry and for both porosities. 展开更多
关键词 porous horizontal concentric cylinders nanofluid flow PERMEABILITY heat transfer
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Shaking table test and numerical analysis of a 1:12 scale model of a special concentrically braced steel frame with pinned connections 被引量:7
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作者 Yu Haifeng Zhang Wenyuan +1 位作者 Zhang Yaochun Sun Yusong 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2010年第1期51-63,共13页
This paper describes shaking table tests of a 1:12 scale model of a special concentrically braced steel frame with pinned connections, which was fabricated according to a one-bay braced frame selected from a typical ... This paper describes shaking table tests of a 1:12 scale model of a special concentrically braced steel frame with pinned connections, which was fabricated according to a one-bay braced frame selected from a typical main factory building of a large thermal power plant. In order to investigate the seismic performance of this type of structure, several ground motion accelerations with different levels for seismic intensity Ⅷ, based on the Chinese Code for Seismic Design of Buildings, were selected to excite the model. The results show that the design methods of the members and the connections are adequate and that the structural system will perform well in regions of high seismicity. In addition to the tests, numerical simulations were also conducted and the results showed good agreement with the test results. Thus, the numerical model is shown to be accurate and the beam element can be used to model this structural system. 展开更多
关键词 concentrically braced steel frame pinned connections shaking table test numerical analysis seismic performance
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Spectral and Energy Efficiency of Line-of-Sight OAM-MIMO Communication Systems 被引量:6
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作者 Rui Chen Hong Zhou +1 位作者 Wen-Xuan Long Marco Moretti 《China Communications》 SCIE CSCD 2020年第9期119-127,共9页
Not only high spectral efficiency(SE)but also high energy efficiency(EE)are required for future wireless communication systems.Radio orbital angular momentum(OAM)provides a new perspective of mode multiplexing to impr... Not only high spectral efficiency(SE)but also high energy efficiency(EE)are required for future wireless communication systems.Radio orbital angular momentum(OAM)provides a new perspective of mode multiplexing to improve SE.However,there are few studies on the EE performance of OAM mode multiplexing.In this paper,we investigate the SE and EE of a misaligned uniform concentric circle array(UCCA)-based multi-carrier multimode OAM and multiple-input multiple-output(MCMM-OAM-MIMO)system in the line-ofsight(LoS)channel,in which two transceiver architectures implemented by radio frequency(RF)analog synthesis and baseband digital synthesis are considered.The distance and angle of arrival(AoA)estimation are utilized for channel estimation and signal detection,whose training overhead is much less than that of traditional MIMO systems.Simulation results validate that the UCCA-based MCMM-OAM-MIMO system is superior to conventional MIMOOFDM system in the EE and SE performances. 展开更多
关键词 orbital angular momentum(OAM) uniform concentric circle array(UCCA) spectral efficiency(SE) energy efficiency(EE)
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Study on element detection and its correction in iron ore concentrate based on a prompt gamma-neutron activation analysis system 被引量:4
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作者 Long Zhao Xu Xu +6 位作者 Jing-Bin Lu Ya-Lin Gong Xiang-Lin Li Wei Zhang Qing-Min Shang Qing-Feng Song Yan-Feng Li 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第4期44-52,共9页
A prompt gamma-neutron activation analysis(PGNAA) system was developed to detect the iron content of iron ore concentrate. Because of the self-absorption effect of gamma-rays and neutrons, and the interference of chlo... A prompt gamma-neutron activation analysis(PGNAA) system was developed to detect the iron content of iron ore concentrate. Because of the self-absorption effect of gamma-rays and neutrons, and the interference of chlorine in the neutron field, the linear relationship between the iron analytical coefficient and total iron content was poor, increasing the error in the quantitative analysis. To solve this problem, gamma-ray self-absorption compensation and a neutron field correction algorithm were proposed, and the experimental results have been corrected using this algorithm. The results show that the linear relationship between the iron analytical coefficient and total iron content was considerably improved after the correction. The linear correlation coefficients reached 0.99 or more. 展开更多
关键词 PROMPT gamma-neutron activation analysis SELF-ABSORPTION Energy spectrum Compensation CORRECTION Iron ORE CONCENTRATE
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Melt-Fluid and Fluid-Fluid Immiscibility in a Na_(2)SO_(4)-SiO_(2)-H_(2)O System and Implications for the Formation of Rare Earth Deposits 被引量:4
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作者 CUI Hao ZHONG Richen +2 位作者 XIE Yuling WANG Xiaolin CHEN Huan 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2021年第5期1604-1610,共7页
Liquid-liquid immiscibility has crucial influences on geological processes,such as magma degassing and formation of ore deposits.Sulfate,as an important component,associates with many kinds of deposits.Two types of im... Liquid-liquid immiscibility has crucial influences on geological processes,such as magma degassing and formation of ore deposits.Sulfate,as an important component,associates with many kinds of deposits.Two types of immiscibility,including(i)fluid-melt immiscibility between an aqueous solution and a sulfate melt,and(ii)fluid-fluid immiscibility between two aqueous fluids with different sulfate concentrations,have been identified for sulfate-water systems.In this study,we investigated the immiscibility behaviors of a sulfate-and quartz-saturated Na_(2)SO_(4)-SiO_(2)-H_(2)O system at elevated temperature,to explore the phase relationships involving both types of immiscibility.The fluid-melt immiscibility appeared first when the Na_(2)SO_(4)-SiO_(2)-H_(2)O sample was heated to~270℃,and then fluid-fluid immiscibility emerged while the sample was further heated to~450℃.At this stage,the coexistence of one water-saturated sulfate melt and two aqueous fluids with distinct sulfate concentrations was observed.The three immiscible phases remain stable over a wide pressure-temperature range,and the appearance temperature of the fluid-fluid immiscibility increases with the increased pressure.Considering that sulfate components occur extensively in carbonatite-related deposits,the fluid-fluid immiscibility can result in significant sulfate fractionation and provides implications for understanding the formation of carbonatite-related rare earth deposits. 展开更多
关键词 geochemistry liquid-liquid immiscibility high sulfate concentration sulfate melt hydrothermal fluids
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Clinical application of concentrated bone marrow aspirate in orthopaedics:A systematic review 被引量:5
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作者 Arianna L Gianakos Li Sun +2 位作者 Jay N Patel Donald M Adams Frank A Liporace 《World Journal of Orthopedics》 2017年第6期491-506,共16页
AIM To examine the evidence behind the use of concentrated bone marrow aspirate(c BMA) in cartilage, bone, and tendon repair; establish proof of concept for the use of cB MA in these biologic environments; and provide... AIM To examine the evidence behind the use of concentrated bone marrow aspirate(c BMA) in cartilage, bone, and tendon repair; establish proof of concept for the use of cB MA in these biologic environments; and provide the level and quality of evidence substantiating the use of cB MA in the clinical setting.METHODS We conducted a systematic review according to PRISMA guidelines. EMBASE, MEDLINE, and Web of Knowledge databases were screened for the use of cB MA in the repair of cartilage, bone, and tendon repair. We extracted data on tissue type, cB MA preparation, cB MA concentration, study methods, outcomes, and level of evidence and reported the results in tables and text.RESULTS A total of 36 studies met inclusion/exclusion criteria and were included in this review. Thirty-one of 36(86%) studies reported the method of centrifugation and preparation of cB MA with 15(42%) studies reporting either a cell concentration or an increase from baseline. Variation of c BMA application was seen amongst the studies evaluated. Twenty-one of 36(58%) were level of evidence Ⅳ, 12/36(33%) were level of evidence Ⅲ, and 3/36(8%) were level of evidence Ⅱ. Studies evaluated full thickness chondral lesions(7 studies), osteochondral lesions(10 studies), osteoarthritis(5 studies), nonunion or fracture(9 studies), or tendon injuries(5 studies). Significant clinical improvement with the presence of hyaline-like values and lower incidence of fibrocartilage on T2 mapping was found in patients receiving cB MA in the treatment of cartilaginous lesions. Bone consolidation and time to bone union was improved in patients receiving cB MA. Enhanced healingrates, improved quality of the repair surface on ultrasound and magnetic resonance imaging, and a decreased risk of re-rupture was demonstrated in patients receiving cB MA as an adjunctive treatment in tendon repair. CONCLUSION The current literature demonstrates the potential benefits of utilizing c BMA for the repair of cartilaginous lesions, bony defects, and tendon injuries in the clinical setting. This study also demonstrates discrepancies between the literature with regards to various methods of centrifugation, variable cell count concentrations, and lack of standardized outcome measures. Future studies should attempt to examine the integral factors necessary for tissue regeneration and renewal including stem cells, growth factors and a biologic scaffold. 展开更多
关键词 Concentrated BONE MARROW aspirate BONE CARTILAGE OSTEOCHONDRAL lesion Osteoarthritis TENDON
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