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In situ Investigation on Layer-by-Layer Deposition of Polyelectrolytes by Quartz Crystal Microbalance

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Chinese Journal of Chemical Physics 2008年第3期21卷 291-294页

作者： Yun-fengYan guang-ming Liu ye-cang Tang guang-zhao Zhang Department of Chemical Physics University of Science and Technology of China Hefei 230025 China

The effect of salt concentration on layer-by-layer deposition of poly（sodium 4-styrene sulfonate）（PSSS）/poly（vinylbenzyl trimethylammonium chloride）（PVTC） was investigated by use of quartz crystal microbalance with dissipation （QCM-D）. The changes in frequency and dissipation demonstrate that the addition of NaC1 leads the thickness of PSSS/PVTC multilayer to increase. The deposition of PSSS/PVTC is dominated by surface charge overcompensation level at lower salt concentrations. However, it is mainly determined by the interpenetration of polyelectrolytes at a higher salt concentration, as reflected in the oscillation of dissipation change.

关键词： Polyelectrolyte Layer-by-layer deposition Quartz crystal microbalance

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服务器无感知计算系统性能优化技术研究综述

软件学报 2025年第1期36卷 47-78页

作者：杨光刘杰曲慕子王帅叶丹钟华中国科学院大学中国科学院软件研究所软件工程技术研究开发中心计算机科学国家重点实验室(中国科学院软件研究所)

服务器无感知计算是新兴的云计算模式,它基于“函数即服务(FaaS)”的范式,以函数为部署和调度的基本单位,为用户提供大规模并行和自动伸缩的函数执行服务,且无需用户管理底层资源.对于用户,服务器无感知计算能够帮助他们摆脱集群底层基... 详细信息

服务器无感知计算是新兴的云计算模式,它基于“函数即服务(FaaS)”的范式,以函数为部署和调度的基本单位,为用户提供大规模并行和自动伸缩的函数执行服务,且无需用户管理底层资源.对于用户,服务器无感知计算能够帮助他们摆脱集群底层基础设施管理的负担,专注于业务层的开发和创新;对于服务提供商,服务器无感知计算将应用分解为细粒度的函数,极大地提高了调度效率和资源利用率.显著的优势让服务器无感知计算迅速吸引了业界的注意,然而,服务器无感知计算与传统云计算迥然不同的计算模式以及对任务各方面的严格限制给应用的迁移带来了诸多障碍,各种越来越复杂的任务也对服务器无感知计算的性能提出了越来越高的要求,服务器无感知计算的性能优化成为一个重要的研究课题.从4个方面对服务器无感知计算系统性能优化技术的相关研究工作进行梳理和综述,并介绍现有的系统实现.(1)介绍面向典型任务的优化技术,包括任务适配和针对特定任务的系统优化;(2)综述沙箱环境的优化工作,包括沙箱方案和冷启动优化技术,它们是决定函数运行速度的核心;(3)概括I/O和通信技术的优化,它们是服务器无感知计算应用程序的主要性能瓶颈;(4)简述相关的资源调度技术,包括面向平台和面向用户的调度策略,它们决定着系统的资源利用率和任务的执行效率.最后,总结当前服务器无感知计算性能优化技术所面临的问题和挑战,并展望未来可能的发展方向.

关键词：服务器无感知计算函数即服务云函数云计算性能优化

High cycle fatigue behavior of titanium microalloyed high-strength beam steels

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Journal of Iron and Steel Research International 2023年第11期30卷 2267-2279页

作者： Zhi-jun Gao guang-fei Pan Yu Song Shui-ze Wang xiao-yu ye Xin-ping Mao Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China Pangang Group Research Institute Co. Ltd.State Key Laboratory of Vanadium and Titanium Resources Comprehensive UtilizationPanzhihua617000SichuanChina guangdong Laboratory for Materials Science and Technology Yangjiang Branch(Yangjiang Advanced Alloys Laboratory)Yangjiang529500GuangdongChina

The realization of an ideal combination of mechanical and fatigue properties is prerequisites for practical application of titanium(Ti)microalloyed steel in automotive *** fatigue behavior of four Ti microalloyed high-strength beam steels with different Ti contents was systematically *** results show that the content of microalloying element Ti has a significant effect on the fatigue properties,especially in the steel with a high Ti *** the experimental Ti microalloyed steel,inclusion-induced crack initiation is the main fatigue failure *** from general fatigue fracture mechanism in Ti-contained steel,no TiN,which is the most detrimental to fatigue behavior,was found in fatigue crack initiation ***,the large-sized TiN and oxide complex inclusion with a core-shell structure is the dominant cause of fatigue *** of the intense-localized deformation at the interface between complex inclusion and matrix,the angular TiN in the outer shell has a serious deteriorating effect on the fatigue properties,which is consistent with the result of the Kernel average misorientation ***,the modification effect of a small amount of MnS on large-sized inclusion is not obvious and has little effect on the fatigue *** more practical guidance,the critical inclusion sizes of the experimental steels were also investigated by experimental extrapolation *** the increasing tensile strength,the inclusion sensitivity of the experimental steels increases,leading to the small critical inclusion size.

关键词： Titanium microalloyed steel High cycle fatigue Fatigue fracture Critical inclusion size

Regulation of intestinal stem cell fate specification

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Science China(Life Sciences) 2015年第6期58卷 570-578页

作者： QI Zhen CHEN ye-guang State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua-Peking Center for Life Sciences School of Life SciencesTsinghua University

The remarkable ability of rapid self-renewal makes the intestinal epithelium an ideal model for the study of adult stem cells. The intestinal epithelium is organized into villus and crypt, and a group of intestinal stem cells located at the base of crypt are responsible for this constant self-renewal throughout the life. Identification of the intestinal stem cell marker Lgr5, isolation and in vitro culture of Lgr5+ intestinal stem cells and the use of transgenic mouse models have significantly facilitated the studies of intestinal stem cell homeostasis and differentiation, therefore greatly expanding our knowledge of the regulatory mechanisms underlying the intestinal stem cell fate determination. In this review, we summarize the current understanding of how signals of Wnt, BMP, Notch and EGF in the stem cell niche modulate the intestinal stem cell fate.

关键词： intestinal stem cells Wnt BMP Notch EGF fate specification

Interplay between TGF-β signaling and receptor tyrosine kinases in tumor development

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Science China(Life Sciences) 2017年第10期60卷 1133-1141页

作者： Qiaoni Shi ye-guang Chen State Key Laboratory of Membrane Biology Tsinghua-Peking Center for Life Sciences School of Life Sciences Tsinghua University Beijing 100084 China

Transforming growth factor-β(TGF-β) signaling regulates cell proliferation, differentiation, migration and death, and plays a critical role in embryogenesis and tissue homeostasis. Its deregulation results in various diseases including tumor *** tyrosine kinases(RTKs), such as epidermal growth factor receptor(EGFR), fibroblast growth factor receptor(FGFR),vascular endothelial growth factor receptor(VEGFR) and platelet-derived growth factor receptor(PDGFR), also play key roles in the development and progression of many types of tumors. It has been realized that TGF-β signaling and RTK pathways interact with each other and their interplay is important for cancer development. They are mutually regulated and cooperatively modulate cell survival and migration, epithelial-mesenchymal transition, and tumor microenvironment to accelerate tumorigenesis and tumor metastasis. RTKs can modulate Smad-dependent transcription or cooperate with TGF-β to potentiate its oncogenic activity,while TGF-β signaling can in turn control RTK signaling by regulating their activities or expression. This review summarizes current understandings of the interplay between TGF-β signaling and RTKs and its influence on tumor development.

关键词： TGF-β receptor tyrosine kinase crosstalk tumor development

BMP signaling in homeostasis, transformation and inflammatory response of intestinal epithelium

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Science China(Life Sciences) 2018年第7期61卷 800-807页

作者： Shan Wang ye-guang Chen The State Key Laboratory of Membrane Biology Tsinghua-Peking Center for Life Sciences School of Life Sciences Tsinghua University

Intestine is the organ for food digestion, nutrient absorption and pathogen defense, in which processes intestinal epithelium plays a central role. Intestinal epithelium undergoes fast turnover, and its homeostasis is regulated by multiple signaling pathways,including Wnt, Notch, Hippo and BMP pathways. BMP signaling has been shown to negatively regulate self-renewal of Lgr5^+ intestinal stem cells, constrains the expansion of intestinal epithelium, therefore attenuating colorectal cancer formation. BMPs and their receptors are expressed in both epithelial and mesenchymal cells, suggesting a two-way interaction between the mesenchyme and epithelium. In this review, we summarize the current understanding of the function of BMP signaling in homeostasis, cancerous transformation and inflammatory response of intestinal epithelium.

关键词： intestinal epithelium BMP signaling Smad ISC CRC

Formal Verification Techniques Based on Boolean Satisfiability Problem

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Journal of Computer Science & Technology 2005年第1期20卷 38-47页

作者： xiao-WeiLit guang-HuiLi MingShao InstituteofComputingTechnology ChineseAcademyofSciencesBeijing100080P.R.China／／GraduateSchoolofChineseAcademyofSciencesBeijing100039P.R.China SchoolofInformationEngineering ZhejiangForestryCollegeHangzhou311300P.R.China／／GraduateSchoolofChineseAcademyofSciencesBeijing100039P.R.China

This paper exploits Boolean satisfiability problem in equivalence checking and model checking respectively. A combinational equivalence checking method based on incremental satisfiability is presented. This method chooses the can didate equivalent pairs with some new techniques, and uses incremental satisfiability algorithm to improve its performance. By substituting the internal equivalent pairs and converting the equivalence relations into conjunctive normal form (CNF) formulas, this approach can avoid the false negatives, and reduce the search space of SAT procedure. Experimental results on ISCAS'85 benchmark circuits show that, the presented approach is faster and more robust than those existed in *** paper also presents an algorithm for extracting of unsatisfiable core, which has an important application in abstraction and refinement for model checking to alleviate the state space explosion bottleneck. The error of approximate extraction is analyzed by means of simulation. An analysis reveals that an interesting phenomenon occurs, with the increasing density of the formula, the average error of the extraction is decreasing. An exact extraction approach for MU subformula, referred to as pre-assignment algorithm, is proposed. Both theoretical analysis and experimental results show that it is more efficient.

关键词： equivalence checking incremental satisfiability minimal unsatisfiableformula model checking

Transient simulation of a pump-turbine with misaligned guide vanes during turbine model start-up

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Acta Mechanica Sinica 2014年第5期30卷 646-655页

作者： ye-Xiang xiao Ruo-Fu xiao State Key Laboratory of Hydroscience and Engineering & Department of Thermal Engineering Tsinghua University College of Water Resources and Civil Engineering China Agricultural University

Experimental studies of a model pump-turbine S-curve characteristics and its improvement by misaligned guide vanes （MGV） were extended to prototype pump turbine through 3-D transient flow simulations. The unsteady Reynolds-averaged Navier-Stokes equations with the SST turbulence model were used to model the transient flow within the entire flow passage of a reversible pump-turbine with and without misaligned guide vanes during turbine model start-up. The unstable S-curve and its improvement by using misaligned guide vane were verified by model test and simulation. The transient flow calculations were used to clarify the variations of pressure pulse and internal flow behavior in the entire flow passage. The use of misaligned guide vanes can eliminate the S-curve characteristics of a pump-turbine, and can significantly increase the pressure pulse amplitude in the entire flow passage and the runner radial forces during start-up. The MGV only decreased the pulse amplitude on the guide vane suction side when the rotating speed was less than 50% rated speed. The hydraulic reason is that the MGV dramatically changed the flow patterns inside the entire flow passage, and destroyed the symmetry of the flow distribution inside the guide vane and runner.

关键词： Transient flow. Pump turbine. Misaligned guide vane Model test Pressure pulse

Regeneration of Ag_XO@SBA-15 for reactive adsorptive desulfurization of fuel

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Petroleum Science 2018年第4期15卷 857-869页

作者： Liqiong Wu Feiyan ye Dong Lei guang Miao Baoyu Liu Zhong Li Jing xiao School of Chemistry and Chemical Engineering South China University of Technology School of Chemical Engineering and Light Industry Guangdong University of Technology

Adsorbent regeneration is critical for a continuous adsorption–regeneration process and often underestimated. In this work,the regeneration of bifunctional AgXO@SBA-15 for [O]-induced reactive adsorptive desulfurization of liquid fuel is reported and further investigated. The spent AgXO@SBA-15 was regenerated in various types of solvents followed by calcination and tested in multiple desulfurization–regeneration cycles. The effects of regenerate solvents were also compared systematically. The original and regenerated AgXO@SBA-15 was characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Nadsorption, X-ray photoelectron spectroscopy and atomic absorption spectrometry. The recovery of desulfurization capacity using various solvents follows the order of acetonitrile [ acetone [ ethanol [ methanol [ water. Owing to the complete reduction of silver species to Ag~0 and severe agglomeration of Ag~0, the bifunctional AgXO@SBA-15 demonstrating [ 85%(2.60 mg-S/g) of sulfur removal dramatically reduced to \ 46%(1.56 mg-S/g) after only 1 st-cycle regeneration. It is suggested that polar organic species strongly adsorbed(or residual) on the spent AgXO@SBA-15, in that case, after solvent wash may contribute to the accelerated decomposition of Ag~+ to Ag~0 in the following calcination step. The desulfurization capacity decreased rather mildly in the later regeneration runs. Cautious choice of regeneration conditions and strategies to rational design stabilized adsorbents is required to avert the adsorbent deactivation.

关键词： Bifunctional Regeneration Oxidation Adsorption Deactivation