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1Principle of equipartition of entransy dissipation for heat exchanger design显示文摘In the present work,a principle of equipartition of entransy dissipation(EoED) for heat exchanger design is established,which says that for a heat exchanger design with given heat duty and heat transfer area,the total entransy dissipation rate reaches the minimum when the local entransy dissipation rate is uniformly distributed along the heat exchanger.When the heat transfer coefficient is unfixed,the total entransy dissipation obtained by the EoED principle is less than that obtained by the principle of equipartition of temperature difference(EoTD).Furthermore,the exchanger effectiveness obtained by the EoED principle is larger than that obtained by the EoTD principle.When the heat transfer coefficient is fixed,the EoED principle is equivalent to the EoTD principle.We show that the equipartition of entropy production(EoEP) and EoED principles give rise to difference in entropy generation and entransy dissipation for a heat exchanger optimization design.The discrepancies are caused by distinct features of entropy production minimization and entransy dissipation minimization principles,the former is to optimize the design of heat exchanger by making the lost available work minimum,while the latter is not involved with heat-work conversion.It is found that the entropy generation number is not suitable for evaluating heat exchanger performance,since it directly depends on the inlet and outlet temperatures of working fluids.On the contrary,the entransy dissipation number is not directly related to the inlet and outlet temperatures of working fluids.Therefore,the entransy dissipation number is more suitable for serving as a criterion to evaluate heat exchanger performance.GUO JiangFeng,XU MingTian & CHENG Lin Institute of Thermal Science and Technology,Shandong University,Jinan 250061,China 2010Science China(Technological Sciences)2010,53,5:46
2Research on solar aided coal-fired power generation system and performance analysis显示文摘Integrating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha- nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a typical SACPG system, considering CO2 avoidance, is 0.098 $/kW·h, lower than that of SEGS, 0.14 $/kW·h.YANG YongPing CUI YingHong HOU HongJuan GUO XiYan YANG ZhiPing WANG NinLing 2008Science China(Technological Sciences)2008,51,8:30
3Next-generation sequencing technology:A technology review and future perspective显示文摘As one of the most powerful tools in biomedical research,DNA sequencing not only has been improving its productivity at an exponential growth rate but has also been evolving into a new layout of technological territories toward engineering and physical disciplines over the past three decades.In this technical review,we look into technical characteristics of the next-generation sequencers and provide insights into their future development and applications.We envisage that some of the emerging platforms are capable of supporting the USD1000 genome and USD100 genome goals if given a few years for technical maturation.We also suggest that scientists from China should play an active role in this campaign that will have a profound impact on both scientific research and societal healthcare systems.ZHOU XiaoGuang1,REN LuFeng1,LI YunTao2,ZHANG Meng1,YU YuDe2 & YU Jun1 1 Key Laboratory of Genome Sciences and Information,Beijing Institute of Genomics,Chinese Academy of Sciences,Beijing 100029,China 2 Institute of Semiconductors,Chinese Academy of Sciences,Beijing 100083,China 2010Science China(Life Sciences)2010,53,1:27
4State-of-the-art review on frequency response of wind power plants in power systems显示文摘With an increasing penetration of wind power in the modern electrical grid, the increasing replacement of large conventional synchronous generators by wind power plants will potentially result in deteriorated frequency regulation performance due to the reduced system inertia and primary frequency response. A series of challenging issues arise from the aspects of power system planning,operation, control and protection. Therefore, it is valuable to develop variable speed wind turbines(VSWTs) equipped with frequency regulation capabilities that allow them to effectively participate in addressing severe frequency contingencies. This paper provides a comprehensive surveyon frequency regulation methods for VSWTs. It fully describes the concepts, principles and control strategies of prevailing frequency controls of VSWTs, including future development trends. It concludes with a performance comparison of frequency regulation by the four main types of wind power plants.Ziping WU Wenzhong GAO Tianqi GAO Weihang YAN Huaguang ZHANG Shijie YAN Xiao WANG 2018Journal of Modern Power Systems and Clean Energy2018,6,1:26
5The revival of thermal utilization from the Sun: interfacial solar vapor generation显示文摘Since solar energy is the ultimate energy resource and a significant amount of global energy utilization goes through heat,there have been persistent efforts for centuries to develop devices and systems for solar–thermal conversion.Most recently,interfacial solar vapor generation,as an emerging concept of solar–thermal conversion,has gained significant attention for its great potentials in various fields such as desalination,sterilization,catalysis,etc.With the advances of rationally designed materials and structures and photon and thermal management at the nanoscale,interfacial solar vapor generation has demonstrated both thermodynamic and kinetical advantages over conventional strategies.In this review,we aim to illustrate the definition,mechanism and figures of merit of interfacial solar vapor generation,and to summarize the development progress of relevant materials and applications,as well as to provide a prospective view of the future.Lin Zhou Xiuqiang Li George W. Ni Shining Zhu Jia Zhu 2019National Science Review2019,6,3:22
6Constructal optimization for a solid-gas reactor based on triangular element显示文摘Entropy generation minimization for heat and mass transfer process in a solid-gas reactor is carried out based on constructal theory by using triangular elemental area. The aspect ratio of the triangular elemental area is optimized under constraint conditions. A number of optimal triangular elements are assembled to a new large rectangular area, which is optimised again. The procedure is repeated until the control-volume is covered, and the complete analytical results are obtained. The effects of some parameters on minimum entropy generation are analysed by nu-merical examples. The results show that smaller entropy generation can be ob-tained when the optimization for a given volume is carried out on the basis of tri-angular elements than those obtained on the basis of rectangular elements.ZHOU ShengBing CHEN LinGen SUN FengRui 2008Science China(Technological Sciences)2008,51,9:21
7Island partition of the distribution system with distributed generation显示文摘In this paper, a novel optimum island partition model based on Tree Knapsack Problem (TKP) is presented for the distribution system integrated with distributed generation (DG), and a Depth-first Dynamic Programming Algorithm (DPA) is used to solve this model. With the considerations of the load priority, controlled/uncontrolled loads, and the constraints of power balance, voltage and equipment capacity, the model can meet the practical engineering requirements very well. The island partition problem of the distribution system integrated with multiple DGs is first decomposed into multiple TKPs, each of which is solved by DPA respectively. Then, the initial optimum island partition scheme is gained through an island combination procedure, and the final island partition scheme is obtained after feasibility checking and adjustment. Since the algorithm proposed owns the advantages of strong theoretical foundation and low computational complexity, it can find the approximate optimal solution within a limited time. The results of examples demonstrate the validity of the new model and algorithm.WANG XuDong & LIN JiKeng* Key laboratory of Power System Simulation and Control of Ministry of Education, Tianjin University, Tianjin 300072, China 2010Science China(Technological Sciences)2010,53,11:21
8近海风电基础桩土作用3D有限元模拟显示文摘针对近海风电桩基础型式,采用接触单元法、表面效应单元法分别构建了桩和土的3D全实体、桩体3D实体有限元模型,以典型海上风电基础桩土作用分析算例,实现了两种模型的有限元计算。计算结果表明,表面效应单元法比接触单元法计算速率高但精度略差,比常规的m法计算精度高,为实际海上风电基础桩土作用的有限元计算分析提供了参考。李炜 郑永明 周永 2010水电能源科学2010,28,8:19
9Hierarchical microstructures with high spatial frequency laser induced periodic surface structures possessing different orientations created by femtosecond laser ablation of silicon in liquids显示文摘High spatial frequency laser induced periodic surface structures(HSFLs)on silicon substrates are often developed on flat surfaces at low fluences near ablation threshold of 0.1 J/cm2,seldom on microstructures or microgrooves at relatively higher fluences above 1 J/cm^2.This work aims to enrich the variety of HSFLs-containing hierarchical microstructures,by femtosecond laser(pulse duration:457 fs,wavelength:1045 nm,and repetition rate:100 kHz)in liquids(water and acetone)at laser fluence of 1.7 J/cm^2.The period of Si-HSFLs in the range of 110–200 nm is independent of the scanning speeds(0.1,0.5,1 and 2 mm/s),line intervals(5,15 and 20μm)of scanning lines and scanning directions(perpendicular or parallel to light polarization direction).It is interestingly found that besides normal HSFLs whose orientations are perpendicular to the direction of light polarization,both clockwise or anticlockwise randomly tilted HSFLs with a maximal deviation angle of 50°as compared to those of normal HSFLSs are found on the microstructures with height gradients.Raman spectra and SEM characterization jointly clarify that surface melting and nanocapillary waves play important roles in the formation of Si-HSFLs.The fact that no HSFLs are produced by laser ablation in air indicates that moderate melting facilitated with ultrafast liquid cooling is beneficial for the formation of HSFLs by LALs.On the basis of our findings and previous reports,a synergistic formation mechanism for HSFLs at high fluence was proposed and discussed,including thermal melting with the concomitance of ultrafast cooling in liquids,transformation of the molten layers into ripples and nanotips by surface plasmon polaritons(SPP)and second-harmonic generation(SHG),and modulation of Si-HSFLs direction by both nanocapillary waves and the localized electric field coming from the excited large Si particles.Dongshi Zhang Koji Sugioka 2019Opto-Electronic Advances2019,2,3:17
10Nanostructured thermoelectric materials:Current research and future challengeZhigang Chen Guang Han Lei Yang Lina Cheng Jin Zou 2012Progress in Natural Science:Materials International2012,22,6:17
11光伏电站-水电站互补发电系统的仿真研究显示文摘以光伏电站、水电站和调节水库为研究对象,基于能量守恒原理,建立了光伏电站-水电站互补发电系统的数学模型,提出了相应的调度算法,给出了仿真算例。分析了光-水抽水蓄能互补发电和简单互补发电两种运行方案的差异,并探讨了调节水库库容问题。仿真实验结果表明太阳能与水能互补发电效果显著,抽水蓄能互补发电方案具有较高的能量利用率。陈峦 2010水力发电2010,36,8:15
12Perspectives of DNA microarray and next-generation DNA sequencing technologies显示文摘DNA microarray and next-generation DNA sequencing technologies are important tools for high-throughput genome research,in revealing both the structural and functional characteristics of genomes.In the past decade the DNA microarray technologies have been widely applied in the studies of functional genomics,systems biology and pharmacogenomics.The next-generation DNA sequencing method was first introduced by the 454 Company in 2003,immediately followed by the establishment of the Solexa and Solid techniques by other biotech companies.Though it has not been long since the first emergence of this technology,with the fast and impressive improvement,the application of this technology has extended to almost all fields of genomics research,as a rival challenging the existing DNA microarray technology.This paper briefly reviews the working principles of these two technologies as well as their application and perspectives in genome research.TENG XiaoKun1 & XIAO HuaSheng1,2 1 National Engineering Center for Biochip at Shanghai,Shanghai 201203,China 2 Shanghai-MOST Key Laboratory of Health and Disease Genomics,Chinese National Human Genome Center,Shanghai 201203,China 2009Science China(Life Sciences)2009,52,1:15
13Pharmacologic approaches to treatment resistant depression:Evidences and personal experience显示文摘AIM: To review evidence supporting pharmacological treatments for treatment-resistant depression(TRD) and to discuss them according to personal clinical experience.METHODS: Original studies, clinical trials, systematic reviews, and meta-analyses addressing pharmacological treatment for TRD in adult patients published from 1990 to 2013 were identified by data base queries(Pub Med, Google Scholar e Quertle Searches) using terms: 'treatment resistant depression', 'treatment refractory depression', 'partial response depression', 'non responder depression', 'optimization strategy', 'switching strategy', 'combination strategy', 'augmentation strategy', selective serotonin reuptake inhibitors antidepressants(SSRI), tricyclic antidepressants(TCA), serotonin norepinephrine reuptake inhibitors antidepressants, mirtazapine, mianserine, bupropione, monoamine oxidase inhibitor antidepressant(MAOI), lithium, thyroid hormones, second generation antipsychotics(SGA), dopamine agonists, lamotrigine, psychostimulants, dextromethorphan, dextrorphan, ketamine, omega-3 fatty acids, S-adenosil-L-metionine, methylfolat, pindolol, sex steroids, glucocorticoid agents. Other citations of interest were further identified from references reported in the accessed articles. Selected publications were grouped by treatment strategy:(1) switching from an ineffective antidepressant(AD) to a new AD from a similar or different class;(2) combining the current AD regimen with a second AD from a different class; and(3) augmenting the current AD regimen with a second agent not thought to be an antidepressant itself.RESULTS: Switching from a TCA to another TCA provides only a modest advantage(response rate 9%-27%), while switching from a SSRI to another SSRI is more advantageous(response rate up to 75%). Evidence supports the usefulness of switching from SSRI to venlafaxine(5 positive trials out 6), TCA(2 positive trials out 3), and MAOI(2 positive trials out 2) but not from SSRI to bupropione, duloxetine and mirtazapine. Three reviews demonstrated that the benefits of intraand cross-class switch do not significantly differ. Data on combination strategy are controversial regarding TCA-SSRI combination(positive results in old studies, negative in more recent study) and bupropion-SSRI combination(three open series studies but not three controlled trails support the useful of this combination) and positive regard mirtazapine(or its analogue mianserine) combination with ADs of different classes. As regards the augmentation strategy, available evidences supported the efficacy of TCA augmentation with lithium salts and thyroid hormone(T3), but are conflicting regard the SSRI augmentation with these two drugs(1 positive trial out of 4 for lithium and 3 out of 5 for thyroid hormone). Double-blind controlled studies showed the efficacy of AD augmentation with aripiprazole(5 positive trials out 5), quetiapine(3 positive trials out 3) and, at less extent, of fluoxetine augmentation with olanzapine(3 positive trials out 6), so these drugs received the FDA indication for the acute treatment of TRD. Results on AD augmentation with risperidone are conflicting(2 short term positive trials, 1 short-term and 1 long-term negative trials). Case series and open-label trials showed that AD augmentation with pramipexole or ropinirole, two dopamine agonists, could be an effective treatment for TRD(response rate to pramipexole 48%-74%, to ropinirole 40%-44%) although one recent double-blind placebo-controlled study does not support the superiority of pramipexole over placebo. Evidences do not justify the use of psychostimulants, omega-3 fatty acids, S-adenosil-Lmetionine, methylfolate, pindolol, lamotrigine, and sex hormone as AD augmentation for TRD. Combining the available evidences with our experience we suggest treating non-responders to one SSRI bupropion or mirtazapine trial by switching to venlafaxine, and nonresponders to one venlafaxine trial by switching to a TCA or, if TCA are not tolerated, combining mirtazapine with SSRI or venlafaxine. In non-responders to two or more ADs(including at least one TCA if tolerated) current AD regimen could be augmented with lithium salts(mainly in patients with bipolar depression or suicidality), SGAs(mostly aripiprazole) or DA-agonists(mostly pramipexole). In patients with severe TRD, i.e., non-responders to combination and augmentation strategies as well as to electroconvulsive therapy if workable, we suggest to try a combination plus augmentation strategy.CONCLUSION: Our study identifies alternative effective treatment strategies for TRD. Further studies are needed to compare the efficacy of different strategies in more homogeneous subpopulations.Antonio Tundo Rocco de Filippis Luca Proietti 2015World Journal of Psychiatry2015,5,3:15
14Review of current diagnostic methods and advances in Helicobacter pylori diagnostics in the era of next generation sequencing显示文摘Helicobacter pylori(H.pylori)infection is highly prevalent in the human population and may lead to severe gastrointestinal pathology including gastric and duodenal ulcers,mucosa associated tissue lymphoma and gastric adenocarcinoma.In recent years,an alarming increase in antimicrobial resistance and subsequently failing empiric H.pylori eradication therapies have been noted worldwide,also in many European countries.Therefore,rapid and accurate determination of H.pylori’s antibiotic susceptibility prior to the administration of eradication regimens becomes ever more important.Traditionally,detection of H.pylori and its antimicrobial resistance is done by culture and phenotypic drug susceptibility testing that are cumbersome with a long turn-around-time.Recent advances in diagnostics provide new tools,like real-time polymerase chain reaction(PCR)and line probe assays,to diagnose H.pylori infection and antimicrobial resistance to certain antibiotics,directly from clinical specimens.Moreover,high-throughput whole genome sequencing technologies allow the rapid analysis of the pathogen’s genome,thereby allowing identification of resistance mutations and associated antibiotic resistance.In the first part of this review,we will give an overview on currently available diagnostic methods for detection of H.pylori and its drug resistance and their implementation in H.pylori management.The second part of the review focusses on the use of next generation sequencing technology in H.pylori research.To this end,we conducted a literature search for original research articles in English using the terms“Helicobacter”,“transcriptomic”,“transcriptome”,“next generation sequencing”and“whole genome sequencing”.This review is aimed to bridge the gap between current diagnostic practice(histology,rapid urease test,H.pylori culture,PCR and line probe assays)and new sequencing technologies and their potential implementation in diagnostic laboratory settings in order to complement the currently recommended H.pylori management guidelines and subsequently improve public health.Daniel Pohl Peter M Keller Valentine Bordier Karoline Wagner 2019World Journal of Gastroenterology2019,25,32:15
15Optimal paths for a light-driven engine with a linear phenomenological heat transfer law显示文摘An irreversible light-driven engine is described in this paper, in which the heat transfer between the working fluid and the environment obeys a linear phenomenological heat transfer law [ q ∝Δ(T -1)], with a working fluid composed of the bimolecular reacting system 2SO 3 F■S 2 O 6 F2. Piston trajectories maximizing work output and minimizing entropy generation are determined for such an engine with rate-dependent loss mechanisms of friction and heat leakage. The optimal control theory is applied to determine the optimal configurations of the piston motion trajectory and the fluid temperature. Numerical examples for the optimal configuration are provided, and the obtained results are compared with those derived with Newtonian heat transfer law [ q ∝Δ(T )].MA Kang, CHEN LinGen & SUN FengRui Postgraduate School, Naval University of Engineering, Wuhan 430033, China 2010Science China Chemistry2010,53,4:14
16Piglet gut microbial shifts early in life:causes and effects显示文摘The gut microbiome has long been known to play fundamentally important roles in the animal health and the well-being of its host. As such, the establishment and maintenance of a beneficial gut microbiota early in life is crucial in pigs, since early gut colonizers are pivotal in the establishment of permanent microbial community structures affecting the health and growth performance of pigs later in life. Emphasizing this importance of early gut colonizers, it is critical to understand the factors impacting the establishment of the piglet gut microbiome at weaning. Factors include, among others, diet, in-feed antibiotics, probiotics and prebiotic administration. The impact of these factors on establishment of the gut microbiome of piglets at weaning includes effects on piglet gut microbial diversity, structure, and succession. In this review, we thoroughly reviewed the most recent findings on the piglet gut microbiome shifts as influenced by weaning, and how these microbiome changes brought about by various factors that have been shown to affect the development of microbiota in piglets. This review will provide a general overview of recent studies that can help to facilitate the design of new strategies to modulate the gut microbiome in order to enhance gastrointestinal health, growth performance and well-being of piglets.Robin B.Guevarra Jun Hyung Lee Sun Hee Lee Min-Jae Seok Doo Wan Kim Bit Na Kang Timothy J.Johnson Richard E.Isaacson Hyeun Bum Kim 2019Journal of Animal Science and Biotechnology2019,10,3:13
17基于LabVIEW的自动测试系统中动态报表的生成方法显示文摘介绍了一种在LabVIEW环境下基于Report Generation Toolkit动态生成报表的方法,该方法通过Activex技术将Mi-crosoft Excel与LabVIEW开发环境集成起来,生成的报表具有任选通道、自动排列数据和自动调整页面的优点,更符合测试系统的要求。王晓兰 李建海 肖骏 2008测控技术2008,27,9:13
18Radio Propagation and Wireless Coverage of LSAA-Based 5G Millimeter-Wave Mobile Communication Systems显示文摘Millimeter-wave(mm Wave) communications will be used in fifth-generation(5G) mobile communication systems, but they experience severe path loss and have high sensitivity to physical objects, leading to smaller cell radii and complicated network architectures. A coverage extension scheme using large-scale antenna arrays(LSAAs) has been suggested and theoretically proven to be cost-efficient in combination with ultradense small cell networks. To analyze and optimize the LSAA-based network deployments, a comprehensive survey of recent advances in statistical mmWave channel modeling is first presented in terms of channel parameter estimation, large-scale path loss models, and small-scale cluster models. Next, the measurement and modeling results at two 5G candidate mmWave bands(e.g., 28 GHz and 39 GHz) are reviewed and compared in several outdoor scenarios of interest, where the propagation characteristics make crucial contributions to wireless network designs. Finally, the coverage behaviors of systems employing a large number of antenna arrays are discussed, as well as some implications on future mmWave cellular network designs.Haiming Wang Peize Zhang Jing Li Xiaohu You 2019China Communications2019,16,5:12
19基于LabVIEW的报表生成显示文摘报表是以打印格式显示数据的一种有效方式,报表生成功能是虚拟仪器测试系统的重要组成部分,一个好的报表生成工具可以使测试系统的开发事半功倍。本文在研究LabVIEW和Word通信技术的基础上,给出了二者的通信模型,并通过电子测压器的上位机系统为例重点介绍了基于Word模板的报表的生成过程,实现了基于LabVIEW测试项目的Word报表自动生成。电子测压器的上位机系统使用该技术后操作更加方便、简单,提高了测试过程的自动化和智能化水平以及测试效率和精度,用户实际使用后给予了很高的评价。董慧群 王福明 2011电子测试2011,22,12:11
20Quasispecies structure,cornerstone of hepatitis B virus infection: Mass sequencing approach显示文摘Hepatitis B virus(HBV)is a DNA virus with complex replication,and high replication and mutation rates,leading to a heterogeneous viral population.The population is comprised of genomes that are closely related,but not identical;hence,HBV is considered a viral quasispecies.Quasispecies variability may be somewhat limited by the high degree of overlapping between the HBV coding regions,which is especially important in the P and S gene overlapping regions,but is less significant in the X and preCore/Core genes.Despite this restriction,several clinically and pathologically relevant variants have been characterized along the viral genome.Next-generation sequencing(NGS)approaches enable high-throughput analysis of thousands of clonally amplified regions and are powerful tools for characterizing genetic diversity in viral strains.In the present review,we update the information regarding HBV variability and present a summary of the various NGS approaches available for research in this virus.In addition,we provide an analysis of the clinical implications of HBV variants and their study by NGS.Francisco Rodriguez-Frias Maria Buti David Tabernero Maria Homs 2013World Journal of Gastroenterology2013,19,41:11
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