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Numerical Analysis on Charging Performance of the Macro-Encapsulating Combined Sensible-Latent Heat Storage System with Structural Parameters

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Journal of Thermal Science 2024年第3期33卷 1026-1036页

作者： wang Wei PAN Zhenfei wang jingfu WU Yuting MA Chongfang Key Laboratory of Enhanced Heat Transfer and Energy Conservation Ministry of EducationCollege of Energy and Power EngineeringBeijing University of TechnologyBeijing100124China Key Laboratory of Heat Transfer and Energy Conversion Beijing MunicipalityCollege of Energy and Power EngineeringBeijing University of TechnologyBeijing100124China

For combined sensible-latent heat storage system(CSLHS)(termed as the hybrid configuration),macro encapsulation can effectively solve the leakage problem of ***,due to the poor thermal conductivity of PCMs,the charging performance of the hybrid configuration slightly increases compared to the solid structure(with only sensible materials).Meanwhile,the natural convection in the PCMs zone could improve the charging ***,how to improve natural convection intensity is a key issue for the CSLHS by macro *** is found that adding fins can significantly enhance natural convection and accelerate the melting of *** this paper,we proposed the hybrid configuration with fins built-in by macro encapsulation,and analyzed its charging performance with different fin structural parameters in the PCM zone by CFD *** the case,the sensible heat storage material is high-temperature concrete and the PCM is a low-melting-point mixed molten *** analyzed the effects of fin number,fin length and fin thickness on the charging performance of the hybrid configuration *** the result,the charging performance increases with the fin number,but the increase rate gradually *** the fin number is 6,the charging performance increases by 20.18%compared to the situation without *** charging performance increases gradually with the fin *** with the hybrid configuration without fin,for each 10 mm increase in fin length,its charging performances increase by 4.09%,5.26%,7.02%,8.77%,11.70%,and 15.79%,*** from number and length of fins,the effect of thickness on the charging performance is very *** the fin thickness increased from 1 mm to 4 mm,the charging performance only increased by 2.3%.It indicates that the main reason for the improving the charging performance is to increase the natural convection intensity by dividing the PCM zone through *** results show that the charging performance

关键词： macro-encapsulation hybrid configuration natural convection structural parameter charging performance

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Mutual feedback between algal blooming and global warming

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Journal of Oceanology and Limnology 2024年第3期42卷 787-801页

作者： Jianrong MA Guijun YANG Xianfu ZHAO Boqiang QIN Kun SHAN Botian ZHOU Yan ZENG jingfu wang Jingan CHEN Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China School of Environment and Ecology Jiangnan UniversityWuxi 214122China Key Laboratory of Ministry of Water Resources for Ecological Impacts of Hydraulic-projects and Restoration of Aquatic Ecosystem Institute of HydroecologyMinistry of Water Resources&Chinese Academy of SciencesWuhan 430079China State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China

Global warming and algal blooms have been two of the most pressing problems faced by the world *** recent decades,numerous studies indicated that global warming promoted the expansion of algal ***,research on how algal blooms respond to global warming is *** warming coupled with eutrophication promoted the rapid growth of phytoplankton,which resulted in an expansion of algal *** blooms are affected by the combined effects of global warming,including increases in temperatures,CO_(2)concentration,and nutrient input to aquatic systems by extreme weather *** the growth of phytoplankton requires CO_(2),they appear to act as a carbon ***,algal blooms will release CH4,CO_(2),and inorganic nitrogen when they die and *** substrate nitrogen increases from decompose algal biomass,more N2O will be released by nitrification and *** comparison to CO_(2),CH4has 28-fold and N2O has 265-fold greenhouse ***,algal blooms in the polar regions may contribute to melting glaciers and sea ice(will release greenhouse gas,which contribute to global warming)by reducing surface albedo,which consequently would accelerate global ***,algal blooms and global warming could form feedback loops which prevent human survival and *** researches shall examine the mechanism,trend,strength,and control strategies involved in this mutual ***,it will promote global projects of environmental protection combining governance greenhouse gas emissions and algal blooms,to form a geoengineering for regulating the cycles of carbon,nitrogen,and phosphorus.

关键词： climate change carbon neutrality eutrophication greenhouse gas glaciers melting geoengineering

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Multislice behavioral modeling based on envelope domain for power amplifiers

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Journal of Systems Engineering and Electronics 2009年第2期20卷 274-277页

作者： wang Huadong Bao jingfu Wu Zhengde School of Electronic Engineering Univ. of Electronics Science and Technology of China Chengdu 610054 P.R. China

An envelope domain multislice behavioral modeling is introduced. The tradition AM-AM and AM- PM characteristics of power amplifiers axe extended to envelope domain and base-band filter is applied to distortion complex envelope signal for description of the envelope memory effect. Using traditional one and two-tone tests, the coefficients of nonlinear model and the FIR filter can be extracted. At last the model has been applied to a 10 W WCDMA Power amplifier to predict its output signal. And simulation results show that the model output conforms very well to the traditional transistor level simulation results.

关键词： behavioral modeling envelope method power amplifiers

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Thermodynamic and Economic Studies of a Combined Cycle for Waste Heat Recovery of Marine Diesel Engine

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Journal of Thermal Science 2022年第2期31卷 417-435页

作者： ZHANG Xinxin CAO Min HE Maogang wang jingfu MOE key laboratory of enhanced heat transfer and energy conservation Beijing University of TechnologyBeijing 100124China Beijing key laboratory of heat transfer and energy conversion Beijing University of TechnologyBeijing 100124China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’an 710049China

In the present study,the thermodynamic and economic performance of a combined thermodynamic cycle formed by an ORC and a Kalina cycle,which can simultaneously recover waste heat of exhaust gas and cooling water of marine engine,has been *** typical marine engines are selected to be the waste heat *** economic indicators are used to analyze the economic performance of this combined thermodynamic cycle system with different marine engine load and under practical comprehensive operating condition of marine *** results of the present study show that the combined thermodynamic cycle system with R123 as organic working fluid has the best *** system with cis-butene has the worst economic *** practical comprehensive operating conditions of ships,R123 has the shortest Payback Periods,which are 8.51 years and 8.14 years for 8 S70 ME-C10.5 engine and 5G95 ME-C10.5 engine,***,payback Periods of Cyclopentane are 11.95 years and 11.90 *** above values are much shorter than 25 years which are the lifetime of a marine *** practical comprehensive operating conditions of ships,the combined cycle system can provide output power which is at least equivalent to 25%of engine *** that R123 will be phased out in near future,cyclopentane may be its good *** can be used safely by correct handling and installing according to manufacturer's instructions.

关键词： marine engine waste heat recovery combined thermodynamic cycle thermodynamic and economic study R123 cyclopentane

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Selection and Evaluation of Dry and Isentropic Organic Working Fluids Used in Organic Rankine Cycle Based on the Turning Point on Their Saturated Vapor Curves

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Journal of Thermal Science 2019年第4期28卷 643-658页

作者： ZHANG Xinxin ZHANG Congtian HE Maogang wang jingfu MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China Beijing Key Laboratory of Heat Transfer and Energy Conversion College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China MOE Key Laboratory of Thermo-Fluid Science and Engineering School of Energy and Power EngineeringXi'an Jiaotong UniversityXi’an 710049China

The organic Rankine cycle(ORC)is a popular technique used in the utilization of low-grade thermal *** wet,dry,and isentropic organic working fluids,the latter two types are more appropriate for ORC *** this paper,the definition of turning point on saturated vapor curve of dry fluid and isentropic fluid was given according to the shape of the saturated curve of working fluids in a T-s *** this basis,the model of near-critical region triangle was *** this model,the thermodynamic performance of 57 kinds of dry and isentropic organic working fluids in ORC was *** performance includes the relation between turning point temperature and cycle thermal efficiency,the relation between near-critical region triangle area and cycle thermal efficiency,the relation between near-critical region triangle area and exergy at turning point temperature,the relation between near-critical region triangle area and reciprocal value of slope of saturated vapor ***,working fluid selection was also conducted in terms of heat source *** was found through theoretical analysis results that the popular R123 is an acceptable choice especially for the utilization of closed type heat *** it will be phased out in near future,then cis-butene,butane,trans-butene,and isobutene are worth studying as its *** is worthy of attention and further research and it can be a good choice for utilization of open type heat source.

关键词： dry fluid isentropic fluid turning point saturated vapor curve near-critical region triangle Organic Rankine Cycle

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Numerical Simulation of Charging Performance of Combined Sensible-Latent Heat Storage System with a Macro-Encapsulation Method

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Journal of Thermal Science 2023年第6期32卷 2008-2017页

作者： wang Wei PAN Zhenfei LEI Biao WU Yuting wang jingfu MA Chongfang Key Laboratory of Enhanced Heat Transfer and Energy Conservation Ministry of EducationCollege of Energy and Power EngineeringBeijing University of TechnologyBeijing100124China Key Laboratory of Heat Transfer and Energy Conversion Beijing MunicipalityCollege of Energy and Power EngineeringBeijing University of TechnologyBeijing100124China

In recent years,heat storage system combining sensible and latent heat materials has received more and more *** this paper,we proposed the hybrid configuration with a macro-encapsulation,and analyzed its charging performance with different influencing factors by CFD *** the case,the sensible heat storage materials are magnesia brick or HT concrete and the phase change materials(PCMs)are mixed molten ***,we analyzed the heat transfer characteristics of the hybrid configuration in charging ***,we analyzed the effect of heating power on charging *** maximum temperature of the heating surface shall not exceed 500℃as the constraint condition,the heat storage capacity increases at first and then decreases with the heating ***,we compared the charging performance of different solid structure and the hybrid *** magnesia brick or HT concrete,the charging performance of the solid structure is better than that of the hybrid configuration,because the thermal conductivity of the molten salt is significantly lower than that of the two sensible heat storage ***,we compared the charging performance of different molten *** hybrid configuration with lower melting point molten salt has better performance because of more intensity natural ***,we analyzed the charging performance of the hybrid configuration used the composite phase change material(CPCM)with high thermal conductivity and specific *** the result,the charging performance increases by 22.5%compared with the solid *** results indicate that the hybrid configuration with the macro-encapsulation method is a potential form of thermal energy storage,but it needs to be further optimized.

关键词： thermal energy storage hybrid configuration natural convection thermophysical property charging performance

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FTA-环介导等温扩增技术直接提取变异链球菌DNA的效果评价

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中国组织工程研究 2025年第5期29卷 1043-1049页

作者：王玥晖尚进杨晨符冬格曹灿张晓东王敬夫北部战区总医院口腔科辽宁省沈阳市110016 空军军医大学第三附属医院颌面外科陕西省西安市710004

背景:变异链球菌是龋病的重要病原菌,及时检测变异链球菌水平对龋病的早发现、早治疗有重要意义。目的:建立并评价FTA-环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术直接提取变异链球菌DNA的应用效果。方法:①制备... 详细信息

背景:变异链球菌是龋病的重要病原菌,及时检测变异链球菌水平对龋病的早发现、早治疗有重要意义。目的:建立并评价FTA-环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术直接提取变异链球菌DNA的应用效果。方法:①制备含有ATCC标准菌株变异链球菌的菌悬液,接种于脑心浸出液培养基,充分混匀后按10倍梯度稀释成7种浓度(4.2×10^(7),4.2×10^(6),4.2×10^(5),4.2×10^(4),4.2×10^(3),4.2×10^(2),4.2×10 CFU/mL),每个稀释级做2个平行对照,并增加无菌水作为空白对照;②分别采用FTA卡、常规煮沸法、试剂盒提取及裂解液提取4种方法直接提取菌株DNA,通过LAMP技术进行扩增,并进行特异性试验,比较4种提取方法的差异。结果与结论:①4种方法提取的DNA均满足LAMP扩增的要求;②特异性试验结果显示,只有变异链球菌才可特异扩增出靶基因;③裂解液提取法最低检测限为4.2×10^(3) CFU/mL,FTA卡提取法最低检测限为4.2×10^(4) CFU/mL,试剂盒提取法和常规煮沸法最低检测限分别为4.2×10^(6) CFU/mL和4.2×10^(7) CFU/mL;④4种提取方法其他方面的比较显示,试剂盒提取法的实验成本、步骤数和时间都是最高;其他3种方法步骤数一致,其中FTA卡所需仪器设备最少,常规煮沸法单次成本最低,裂解液提取法所需时间最少;FTA卡和裂解液提取法仅需少量菌即可提取成功,后者在时间方面优于FTA卡,但相较于FTA卡其单次成本高,所需设备多;⑤结果说明,该研究建立的FTA-LAMP技术具有操作简便、特异性强、灵敏度高、结果可视化等优势,有望为高效提取检测变异链球菌提供新途径。

关键词：变异链球菌环介导等温扩增 FTA卡 DNA 可视化

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The oxygen isotopic composition of phosphate as an effective tracer for phosphate sources in Hongfeng Lake

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Acta Geochimica 2017年第4期36卷 619-625页

作者： Yongxue Ji Jingan Chen Runyu Zhang Yong Liu jingfu wang State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

In order to characterize the oxygen isotopic composition of internal phosphate and explore the possibility of using these data to identify phosphate sources, we measured oxygen isotopic compositions of phosphate(δ^(18)O_p) in sediment pore water in Hongfeng Lake, a typical deep-water lake in a mountainous area. These data, in combination with δ^(18)O_p in surface water samples and water column samples, were successfully used to identify phosphate sources. The δ^(18)O_p value of sediment pore water ranged from 15.2% to 15.8%, with an average value of 15.5%—the δ^(18)O_p value of internal phosphate. The δ^(18)O_p values decreased gradually through the water column from 19.4% in surface water to 16.4% in deeper water, implying that internal phosphate had more negative δ^(18)O_p values than external phosphate. This finding was substantiated by horizontal variations in δ^(18)O_p values, which decreased with increasing distance from inflowing rivers. All collected evidence suggests that external and internal phosphate have distinctly different isotopic signatures and that these signatures have not been considerably altered by biological mediation in Hongfeng Lake. Therefore, δ^(18)O_p can be used to distinguish phosphate sources. A two-endmember mixing model showed that internal phosphate had an average contribution of 40%, highlighting the influence of internal phosphorus loading on aqueous phosphate and eutrophication. This study illustrates the need to reduce the internal phosphorus load from sediment and provides guidance for nutrient management and in-lake restoration treatment in Hongfeng Lake. The data presented here are limited, but serve to highlight the great potential of δ^(18)O_p as an effective tracer for identifying phosphate sources. Systematic investigations of the oxygen isotopic compositions of external phosphate, internal phosphate, and phosphate through the water column, in combination with in-lake P biogeochemical cycle study, would be desirable in fu

关键词： Phosphate source δ18Op Eutrophication Hongfeng Lake

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氧纳米气泡改性颗粒对城市污染河流的增氧除磷效率研究

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地球与环境 2024年第2期52卷 213-220页

作者：徐述王敬富杨永琼杨海全朱正杰陈敬安贵州师范大学地理与环境学院中国科学院地球化学研究所环境地球化学国家重点实验室中国科学院大学百色学院

缺氧是城市污染河流水质持续恶化的关键诱因。本研究利用醇-水替换法将氧纳米气泡负载到膨润土、凹凸棒石和白云母矿物表面开发了氧纳米气泡改性矿物材料,并在室内开展了城市污染河流沉积物柱芯增氧除磷试验研究。结果表明,投加氧纳米... 详细信息

缺氧是城市污染河流水质持续恶化的关键诱因。本研究利用醇-水替换法将氧纳米气泡负载到膨润土、凹凸棒石和白云母矿物表面开发了氧纳米气泡改性矿物材料,并在室内开展了城市污染河流沉积物柱芯增氧除磷试验研究。结果表明,投加氧纳米气泡改性矿物材料使沉积物-水界面溶解氧含量快速提升,最高达7.0 mg/L以上,沉积物表层1.0 cm转变为好氧状态。与对照组相比,实验组柱芯上覆水体总磷含量降低90%以上。沉积物-水界面溶解氧的提升提高了表层沉积物氧化还原电位,抑制硫酸盐还原和还原态S^(2-)的形成,增加了沉积物铁氧化物对磷酸盐的固持能力。16S rRNA分析表明,投加氧纳米气泡改性矿物材料抑制了Longilinea和Syntrophomonas在表层沉积物中的生长,促进了Thermomonas的富集,微生物群落的变化显示了底栖生物生存环境的改善。Acidovorax和Acinetobacter丰度增加也反映了增氧过程中,硝酸盐还原亚铁氧化菌和聚磷菌对磷下降的作用。氧纳米气泡改性矿物材料能快速提升沉积物-水界面含氧性,有效抑制沉积物磷的释放,在城市河流水质改善和内源污染原位控制方面具有良好的应用前景。

关键词：氧纳米气泡沉积物-水界面增氧抑磷城市污染河流

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Microscale Chemical Features of Sediment-Water Interface in Hongfeng Lake

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Journal of Earth Science 2016年第6期27卷 1038-1044页

作者： jingfu wang Jing'an Chen Zhihui Dai Jian Li Yang Xu Jing Luo State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of Sciences Faculty of Resources and Environment Guizhou University

In situ microscale distributions of 02, H2S, pH and redox potential in sediments of Hongfeng Lake, SW China, were investigated using the powerful microsensor technique. Our results show that O2 was depleted within the top 3.9 mm in surface sediments, and H2S was subsequently detected at -6.0 mm depth, and reached its maximum concentrations at -25 mm. The degradation of organic matter and reduction of sulfate might be the major pathways of producing H2S in sediments, pH rapidly reduced in surface layers mainly due to H＋ release in the oxidation of organic matter. Eh also decreased sharply in surface sediments, probabl indicating the coexistence of Fe and Mn oxides with O2 in aerobic region. Furthermore, the programme of PROFILE was applied to model the 02 gradient, and good fit was obtained between the simulative values and the factual values both in sediments and in the diffusive boundary layer （DBL）. The results indicate that the depth-integrated O2 consumption rates within sediments were 0.083 and 0.134 nmol·m-3·s-1 in site S1 and site S2, respectively. In addition, there were distinct DBL in two sediment profiles, with 1.2 mm thickness in S1 and 0.9 mm thickness in S2. The diffusive fluxes of O2 within the DBL were 67.13 nmol·m-2·s-1 in S1 and 88.54 nmol·m-2·s-1 in S2.

关键词： microscale chemical feature DBL sediment Hongfeng Lake.

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