检索结果-南通市图书馆

Effect of chlorine content of chlorophenols on their adsorption by mesoporous SBA-15

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2012年第8期24卷 1411-1417页

作者： Qingdong Qin Ke Liu Dafang fu Haiying gao School of Civil Engineering Southeast UniversityNanjing 210096China Department of Man-Machine and Environment Engineering Nanfing University of Aeronautics and AstronauticsNanfing 210016China

Studies on the effect of the chlorine content of chlorophenols （CPs） on their adsorption from aqueous solution by mesoporous SBA-15 are important in understanding the mechanisms of CP adsorption. In this study, three CPs with different degrees of chlorine content （i.e., 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol） were investigated. The effects of parameters such as temperature and solution pH were studied. The results showed that CP adsorption by SBA- 15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH. Thermodynamic parameters such as Gibbs free energy change （AGO）, enthalpy change （△H^0） and entropy change （△S^0） were also calculated. By comparison of the adsorption coefficient of CPs with varying physical-chemical properties （size, hydrophobicity and electron density）, we propose that hydrophobic interactions between CPs and the SBA-15 surface, as well as electron donor-acceptor （EDA） complexes between oxygen of the siloxane surface of SBA-15 （e--donor） and the n-system of the CPs （e--acceptor）, were dominant adsorption mechanisms.

关键词： chlorophenols mesoporous SBA-15 adsorption pH temperature

Machining the Integral Impeller and Blisk of Aero-Engines:A Review of Surface Finishing and Strengthening Technologies

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第3期30卷 528-543页

作者： Youzhi fu Hang gao Xuanping Wang Dongming Guo key laboratory for precision and non-traditional machining technology of ministry of education dalian university of technologyDalian 116024China

The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has signif- icant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and inte- grated finishing and strengthening technologies and dis- cusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.

关键词： Integral impeller and blisk Aero-engine Surface integrity Surface finishing Surface strengthening

Effects of the Nozzle Design on the Properties of Plasma Jet and Formation of YSZ Coatings under Low Pressure Conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2016年第5期29卷 954-961页

作者： SUN Chengqi gao Yang YANG Deming fu Yingqing College of Material Science and Engineering Dalian Maritime University Key Laboratory of Ship-Machinery Maintenance & Manufacture Dalian Maritime University

How to control the quality of the coatings has become a major problem during the plasma spraying. Because nozzle contour has a great influence on the characteristic of the plasma jet, two kinds of plasma torches equipped with a standard cylindrical nozzle and a converging-diverging nozzle are designed for low pressure plasma spraying（LPPS） and very low pressure plasma spraying（VLPPS）. Yttria stabilized zirconia（YSZ） coatings are obtained in the reducing pressure environment. The properties of the plasma jet without or with powder injection are analyzed by optical emission spectroscopy, and the electron temperature is calculated based on the ratio of the relative intensity of two Arlspectral lines. The results show that some of the YSZ powder can be vaporized in the low pressure enlarged plasma jet, and the long anode nozzle may improve the characteristics of the plasma jet. The coatings deposited by LPPS are mainly composed of the equiaxed grains and while the unmelted powder particles and large scalar pores appear in the coatings made by VLPPS. The long anode nozzle could improve the melting of the powders and deposition efficiency, and enhance the coatings＇ hardness. At the same time, the long anode nozzle could lead to a decrease in the overspray phenomenon. Through the comparison of the two different size＇s nozzle, the long anode is much more suitable for making the YSZ coatings.

关键词： plasma torch yttria stabilized zirconia electron temperature equiaxed grain thermal barrier coatings

New progress in understanding the origins of modern humans in China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2017年第12期60卷 2160-2170页

作者： gao Xing PENG Fei fu QiaoMei LI Feng Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijing 100044 University of the Chinese Academy of Sciences Beijing 100049China Department of Early Prehistory and Quaternary Ecology University of TubingenTubingen 72070Germany

Hypotheses concerning the origins of modern humans have been intensively debated, and two competing models, the recent "Out-of-Africa" and "Multiregional Evolution" paradigms, have dominated research and discussions for decades. Evidence from China has played a fundamental role in this debate: regional continuity and replacement by populations in-migrated from Africa have both been suggested and supported mainly by paleoanthropologists and geneticists, respectively. As more evidence has accumulated, new results obtained, and more scholars from various disciplines become involved, supporters of the recent "Out-of-Africa" model agree more or less with the "Multiregional Evolution" model regarding the complex history of modern humans and their interbreeding with other archaic populations(e.g., Neandertals). Recent discoveries of new human fossils, Paleolithic archaeological materials, and ancient DNA evidence in China have yielded a large body of information regarding the formation and development of modern humans in this region. However, controversies continue, including that most molecular biologists insist on the replacement of archaic populations by modern humans dispersed from Africa, while most paleoanthropologists and archaeologists propose an enhanced "Continuity with Hybridization" model. In this paper, we compile new results and progress in China and present the current debates and issues on the origins of modern humans. Finally, we offer several suggestions for future studies.

关键词： China Origins of modern humans Modern behavior Recent out-of-Africa Continuity with hybridization Interdisciplinary research

Flow boiling heat transfer in copper foam fin microchannels with different fin widths using R134a

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第11期66卷 3245-3258页

作者： gao WuHuan fu Kai XU XiangHua LIANG XinGang School of Aerospace Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of EducationTsinghua UniversityBeijing 100084China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

Heat sinks of copper foam fin microchannels are developed to deal with cooling *** heat sinks consist of fins made of copper foam and *** channels are 0.5 mm in width and 1 mm in height,and the fins are 0.5 and 2.0 mm in *** boiling experiments are conducted using R134a at subcooled and saturated inlet *** heat flux is between 22 and 172 W/cm^(2),and the mass flux ranges from 264 to 1213 kg/(m^(2)s).The influence of the quality,the heat flux,and the mass flow rate on the heat transfer coefficient is *** is found that wider fin raises the heat transfer coefficient.A correlation is developed based on heat transfer mechanisms,and it predicts the experimental result with a 12%mean absolute *** with a solid fin microchannels heat sink,the heat transfer coefficient of the copper foam fin microchannels is higher(up to 60%)when the heat flux is lower than 100 W/cm^(2).The copper foam fin microchannels may enhance the heat transfer coefficient and reduce the pressure drop at the same time.

关键词： microchannel copper foam flow boiling heat transfer correlation

Projected changes in extreme snowfall events over the Tibetan Plateau based on a set of RCM simulations

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2024年第5期17卷 3-9页

作者： Yuanhai fu Xuejie gao Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjingChina University of Chinese Academy of Sciences BeijingChina

Extreme snowfall events over the Tibetan Plateau(TP)cause considerable damage to local society and natural *** this study,the authors investigate the projected changes in such events over the TP and its surrounding areas based on an ensemble of a set of 21st century climate change projections using a regional climate model,*** model is driven by five CMIP5 global climate models at a grid spacing of 25 km,under the RCP4.5 and RCP8.5 *** modified ETCCDI extreme indices-namely,SNOWTOT,S1mm,S10mm,and Sx5day-are employed to characterize the extreme snowfall ***4 generally reproduces the spatial distribution of the indices over the region,although with a tendency of *** the projected changes,a general decrease in SNOWTOT is found over most of the TP,with greater magnitude and better cross-simulation agreement over the eastern *** the simulations project an overall decrease in S1mm,ranging from a 25%decrease in the west and to a 50%decrease in the east of the *** S10mm and Sx5day are projected to decrease over the eastern part and increase over the central and western parts of the ***,S10mm shows a marked increase(more than double)with high cross-simulation agreement over the central *** increases in all four indices are found over the Tarim and Qaidam basins,and northwestern China north of the *** projected changes show topographic dependence over the TP in the latitudinal direction,and tend to decrease/increase in low-/high-altitude areas.

关键词： Extreme snowfall Regional climate model Tibetan plateau Climate change

General explicit solutions of most economic sections and applications for trapezoidal and parabolic channels

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第5期31卷 1034-1042页

作者： Yan-cheng Han Said MEasa Xue-ping gao School of Water Conservancy and Environment University of JinanJinan 250022China Department of Civil Engineering Ryerson UniversityTorontoOntarioCanada State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

A channel section that has minimum construction cost is known as the most economic *** a section has important implications for economic ***,the most economic section is a complex optimization model with nonlinear objective function and constraints that is difficult to use by ordinary engineers.A general simple formula for the most economic section has not been *** this paper,the general differential equation for the most economic section is derived using Lagrange multiplier optimization method.A simple method to solve the most economic section is proposed that converted the optimization model into a general equation for the most economic section of any *** solving this equation,the dimensions of the most economic section are directly *** illustrate,the direct formula for trapezoidal section is *** aid application in practice,a simple explicit iterative formula for trapezoidal sections is *** direct and explicit iterative formulas were *** proposed method is superior to the classical optimization method and as such represent a valuable tool for open channel *** illustrate the versatility of the presented method,a direct formula for the parabolic section was also derived.

关键词： Most economic section channel parabolic explicit hydraulic section

Highly Optimized Code Generation for Stencil Codes with Computation Reuse for GPUs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2016年第6期31卷 1262-1274页

作者： Wen-Jing Ma Kan gao Guo-ping Long Laboratory of Parallel Software and Computing Science Institute of Software Chinese Academy of Sciences Beijing 100190 China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China Information Center China Association for Science and Technology Beijing 100863 China

Computation reuse is known as an effective optimization technique. However, due to the complexity of modern GPU architectures, there is yet not enough understanding regarding the intriguing implications of the interplay of compu- ration reuse and hardware specifics on application performance. In this paper, we propose an automatic code generator for a class of stencil codes with inherent computation reuse on CPUs. For such applications, the proper reuse of intermediate results, combined with careful register and on-chip local memory usage, has profound implications on performance. Current state of the art does not address this problem in depth, partially due to the lack of a good program representation that can expose all potential computation reuse. In this paper, we leverage the computation overlap graph （COG）, a simple representation of data dependence and data reuse with ＂element view＂, to expose potential reuse opportunities. Using COG, we propose a portable code generation and tuning framework for GPUs. Compared with current state-of-the-art code generators, our experimental results show up to 56.7% performance improvement on modern GPUs such as NVIDIA C2050.

关键词： GPGPU OpenCL stencil code generation computation reuse

Small extracellular vesicles derived from human induced pluripotent stem cell-differentiated neural progenitor cells mitigate retinal ganglion cell degeneration in a mouse model of optic nerve injury

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第2期20卷 587-597页

作者： Tong Li Hui-Min Xing Hai-Dong Qian Qiao gao Sheng-Lan Xu Hua Ma Zai-Long Chi State Key Laboratory of Ophthalmology Optometry and Visual ScienceEye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina National Clinical Research Center for Ocular Diseases Eye HospitalWenzhou Medical UniversityWenzhouZhejiang ProvinceChina

Several studies have found that transplantation of neural progenitor cells(NPCs)promotes the survival of injured ***,a poor integration rate and high risk of tumorigenicity after cell transplantation limits their clinical *** extracellular vesicles(sEVs)contain bioactive molecules for neuronal protection and *** studies have shown that stem/progenitor cell-derived sEVs can promote neuronal survival and recovery of neurological function in neurodegenerative eye diseases and other eye *** this study,we intravitreally transplanted sEVs derived from human induced pluripotent stem cells(hiPSCs)and hiPSCs-differentiated NPCs(hiPSC-NPC)in a mouse model of optic nerve *** results show that these intravitreally injected sEVs were ingested by retinal cells,especially those localized in the ganglion cell *** with hiPSC-NPC-derived sEVs mitigated optic nerve crush-induced retinal ganglion cell degeneration,and regulated the retinal microenvironment by inhibiting excessive activation of *** analysis further revealed that hiPSC-NPC derived sEVs transported neuroprotective and anti-inflammatory miRNA cargos to target cells,which had protective effects on RGCs after optic nerve *** findings suggest that sEVs derived from hiPSC-NPC are a promising cell-free therapeutic strategy for optic neuropathy.

关键词： exosome miRNA neural progenitor cell neurodegeneration neuroinflammation neuroprotection optic nerve crush optic neuropathy retinal ganglion cell small extracellular vesicles