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Validation concurrency control protocol in parallel real-time database systems

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Journal of Central South University of Technology 2002年第3期9卷 197-201页

作者： LEI Xiang-dong(雷向东) YUAN xiao-li(袁晓莉) College of Information Science and Engineering Central South University Changsha 410083 China College of Information Science and Engineering Central South University Changsha 410083 China

In parallel real-time database systems, concurrency control protocols must satisfy time constraints as well as the integrity constraints. The authors present a validation concurrency control(VCC) protocol, which can enhance the performance of real-time concurrency control mechanism by reducing the number of transactions that might miss their deadlines, and compare the performance of validation concurrency control protocol with that of HP2PL(High priority two phase locking) protocol and OCC-TI-WAIT-50(Optimistic concurrency control-time interval-wait-50) protocol under shared-disk architecture by simulation. The simulation results reveal that the protocol the author presented can effectively reduce the number of transactions restarting which might miss their deadlines and performs better than HP2PL and OCC-TI-WAIT-50. It works well when arrival rate of transaction is lesser than threshold. However, due to resource contention the percentage of missing deadline increases sharply when arrival rate is greater than the threshold.

关键词： parallel database system real-time database concurrency control validation transactions

Effect of metal catalyst on the mechanism of hydrogen spillover in three-dimensional covalent-organic frameworks

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Chinese Physics B 2017年第2期26卷 412-419页

作者： Xiu-Ying liu Jing-Xin Yu xiao-dong li Gui-Cheng liu xiao-Feng li Joong-Kee Lee College of Science Henan University of Technology Zhengzhou 450000 China Center for Energy Convergence Research Green City Research Institute Korea Institute of Science and Technology (KIST) Seou102792 Republic of Korea College of Physical and Electronic Information Luoyang Normal University Luoyang 471022 China

Hydrogen spillover mechanism of metal-supported covalent-organic frameworks COF-105 is investigated by means of the density functional theory, and the effects of metal catalysts M_4（Pt_4, Pd_4, and Ni_4） on the whole spillover process are systematically analyzed. These three metal catalysts exhibit several similar phenomena：（i） they prefer to deposit on the tetra（_4-dihydroxyborylphenyl） silane（TBPS） cluster with surface-contacted configuration;（ii） only the H atoms at the bridge site can migrate to 2,3,6,7,10,11-hexahydroxy triphenylene（HHTP） and TBPS surfaces, and the migration process is an endothermic reaction and not stable;（iii） the introduction of M_4 catalyst can greatly reduce the diffusion energy barrier of H atoms, which makes it easier for the H atoms to diffuse on the substrate surface. Differently, all of the H2 molecules spontaneously dissociate into H atoms onto Pt_4 and Pd_4clusters. However, the adsorbed H2 molecules on Ni_4 cluster show two types of adsorption states： one activated state with stretched H–H bond length of 0.88 ？A via the Kubas interaction and five dissociated states with separated hydrogen atoms. Among all the M_4 catalysts, the orders of the binding energy of M_4 deposited on the substrate and average chemisorption energy per H2 molecule are Pt_4〉Ni_4〉Pd_4. On the contrary, the orders of the migration and diffusion barriers of H atoms are Pt_4

关键词： covalent-organic frameworks hydrogen spillover hydrogen storage density functional theory

Formation and characterization of core-shell CL-20/TNT composite prepared by spray-drying technique

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Defence Technology（防务技术） 2021年第6期17卷 1936-1943页

作者： Chang-gui Song xiao-dong li Yue Yang Hui-min liu Ying-xin Tan Jing-yu Wang School of Environment and Safety Engineering North University of ChinaTaiyuan030051China

The core-shell 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane/2,4,6-Trinitrotoluene(CL-20/TNT)composite was prepared by spray-drying method in which sensitive high energy explosive(CL-20)was coated with insensitive explosive(TNT).The structure and properties of different formulations of CL-20/TNT composite and CL-20/TNT mixture were characterized by scanning electron microscopy(SEM),Transmission electron microscopy(TEM),Laser particle size analyzer,X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),differential scanning calorimetry(DSC),impact sensitivity test and detonation *** results of SEM,TEM,XPS and XRD show that e-CL-20 particles are coated by *** the ratio of CL-20/TNT is 75/25,core-shell structure is well formed,and thickness of the shell is about 20e30 *** the analysis of heat and impact show that with the increase of TNT content,the TNT coating on the core-shell composite material can not only catalyze the thermal decomposition of core material(CL-20),but also greatly reduce the impact *** with the CL-20/TNT mixture(75/25)at the same ratio,the characteristic drop height of core-shell CL-20/TNT composite(75/25)increased by 47.6%and the TNT coating can accelerate the nuclear decomposition in the CL-20/TNT ***,the preparation of the core-shell composites can be regarded as a unique means,by which the composites are characterized by controllable decomposition rate,high energy and excellent mechanical sensitivity and could be applied to propellants and other fields.

关键词： Energetic materials CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) TNT(2,4,6-Trinitrotoluene) Spray-drying method Core-shell structure

Combined Therapy against Recurrent Hemangiopericytoma:A Case Report

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Clinical oncology and cancer researeh 2012年第2期9卷 141-143页

作者： xiao-dong li Jing-ting Jiang Chang-ping Wu Department of Oncology The Third Affiliated Hospital of Soochow University

A patient with a seven-year history of recurrent metastatic hemangiopericytoma(HPC) was *** his treatment,he received surgical resection,radiotherapy,radiofrequency hyperthermia and chemotherapy using combined doxorubicin,dacarbazin, vincristine,ginsenoside Rg3,and recombinant human *** synergistic method provides an encouraging model for treating HPC.

关键词： hemangiopericytoma surgical procedures radiotherapy chemotherapy angiogenesis inhibitors

Effects of SO_2 and SO_3 on the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans by de novo synthesis

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第5期11卷 363-369页

作者： Ke SHAO Jian-hua YAN xiao-dong li Sheng-yong LU Mu-xing FU Ying-lei WEI State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

The effects of SO2,SO3 on de novo synthesis of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were studied using model fly ashes incorporating copper oxide and activated carbon. It was found that the inhibitive effect of SO2 on PCDD/Fs formation is similar to that of SO3. To investigate the inhibition mechanism,CuSO4 formations from both CuO and CuCl2 were examined. The ability of SO3 to convert CuCl2 and CuO on a silica support into sulfate is much stronger than that of SO2. However,replacing silica by activated carbon leads to a much high conversion of CuCl2 to CuSO4 in the presence of SO2. The promotion by activated carbon is explained by the reduction of CuCl2 to Cu2Cl2 and the eventual conversion of Cu2Cl2 into CuSO4 is the main inhibition mechanism of SO2 on de novo synthesis of PCDD/Fs.

关键词： Cuprous chloride Model fly ash Sulfation Cupric chloride

Towards rational design in electrochemical denitrification by analyzing pH dependence

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National Science Review 2024年第6期11卷 223-232页

作者： Huan li dong Luan Jun Long xiaoyan Fu Jianping xiao State Key Laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

A small fraction of NOx（<1%） always exists in CO2feedstock（e.g. exhausted gas）, which can significantly reduce the efficiency of CO2electroreduction by ～30%. Hence, electrochemical denitrification is the precondition of CO2electroreduction. The pH effect is a key factor, and can be used to tune the selectivity between N2and N2O production in electrochemical denitrification. However, there has been much controversy for many years about the origin of pH dependence in electrocatalysis. To this end, we present a new scheme to accurately model the pH dependence of the electrochemical mechanism. An extremely small pH variation from pH 12.7 to pH 14 can be accurately reproduced for N2O production. More importantly,the obviously different pH dependence of N2production, compared to N2O, can be attributed to a cascade path. In other words, the N2was produced from the secondary conversion of the as-produced N2O molecule（the major product）, instead of the original reactant NO. This is further supported by more than 35 experiments over varying catalysts（Fe, Ni, Pd, Cu, Co, Pt and Ag）, partial pressures（20%, 50% and100%） and potentials（from -0.2 to 0.2 V vs. reversible hydrogen electrode）. All in all, the insights herein overturn long-lasting views in the field of NO electroreduction and suggest that rational design should steer away from catalyst engineering toward reactor optimization.

关键词： electrocatalysis denitrification pH-dependence nitric oxide reduction reaction mechanism

Evaluation of Breeding Programs Combining Genomic Information in Chinese Holstein

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Agricultural Sciences in China 2011年第12期10卷 1949-1957页

作者： CHEN Jun WANG Ya-chun ZHANG Yi SUN dong-xiao ZHANG Sheng-li ZHANG Yuan College of Animal Science and Technology/National Engineering Laboratory for Animal Breeding/Key Laboratory of Agricultural Animal Genetics and Breeding China Agricultural University Beijing 100193 P.R.China

Current study adopted gene flow theory and selection index method to compare the breeding efficiency of three breeding plans in the Chinese Holstein cattle using ZPLAN software. Simulated conventional progeny-testing program （PT） and young sire program （YS） were compared with breeding program using genomic selection （GS） taking parameters derived from Chinese Holstein breeding system. The results showed that, GS shortened generation interval by 1.5-2.2 years, and increased the genetic progress by 30-50%, comparing to PT and YS, respectively. Economic analysis showed that GS could obtain a higher breeding efficiency, being 119 and 97% higher than that of PT and YS, respectively; and GS was also powerful in improving functional traits with a low heritability. Main factors affecting breeding efficiency in GS were further discussed, including selection intensity, accuracy and the cost of SNP genotyping. Our finding provided references for future designing and implementing GS in Chinese dairy population.

关键词： Chinese Holstein genomic selection progeny-testing program young sire program breeding plan

Quantitatively Evaluating the Erosion and Preservation of Supergene Oxide Zones:Evidence from the Yulong Porphyry Cu Deposit,Eastern Tibetan Plateau

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Journal of Earth Science 2024年第1期35卷 280-282页

作者： xiao-dong Deng Jian-Wei li State Key Laboratory of Geological Processes and Mineral Resources and School of Earth ResourcesChina University of GeosciencesWuhan 430074China

*** and erosion of sulfide ore deposits are important for understanding the post-mineralization processes that have significant effects on the preservation of primary orebodies(Velasco et al.,2013;Braxton et al.,2009;Brimhall et al.,1985).Supergene oxide zones are often developed in sulfide ore deposits,and are mainly composed of iron oxides and hydroxides zones in weathering profile(Andrew,1984;Thornber et al.,1981).

关键词： Eastern Tibetan weathering

Phase transitions in bismuth under rapid compression

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Chinese Physics B 2019年第3期28卷 300-303页

作者： dong-liang Yang Jing liu Chuan-Long lin Qiu-Min Jing Yi Zhang Yu Gong Yan-Chun li xiao-dong li Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of Science Center for High Pressure Science and Technology Advanced Research National Key Laboratory for Shock Wave and Detonation Physics Institute of Fluid PhysicsChinese Academy of Engineering Physics

The structural phase transitions of bismuth under rapid compression has been investigated in a dynamic diamond anvil cell using time-resolved synchrotron x-ray diffraction. As the pressure increases, the transformations from phase I,to phase II, to phase III, and then to phase V have been observed under different compression rates at 300 K. Compared with static compression results, no new phase transition sequence appears under rapid compression at compression rate from 0.20 GPa/s to 183.8 GPa/s. However, during the process across the transition from phase III to phase V, the volume fraction of product phase as a function of pressure can be well fitted by a compression-rate-dependent sigmoidal *** resulting parameters indicate that the activation energy related to this phase transition, as well as the onset transition pressure, shows a compression-rate-dependent performance. A strong dependence of over-pressurization on compression rate occurs under rapid compression. A formula for over-pressure has been proposed, which can be used to quantify the over-pressurization.

关键词： bismuth high pressure rapid compression over-pressurization