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Phosphorus accumulation and eutrophication in feed-supply freshwater fishponds

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Journal of Environmental Sciences 2006年第4期18卷 816-821页

作者： zhang Ming-kui FANG Li-ping Institute of Soil and Water Resources and Environmental Science College of Natural Resource and Environmental Sciences Zhejiang UniversityHangzhou 310029 China

The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus （P） input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a （Chl-a） in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments. Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg. Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P （NH4Cl-P） and potentially labile P （NaOH-IP） were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyll-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds （12μg/L）〈 fishponds without feed supply （24 μg/L）〈 fishponds with feed supply （66 μg/L）. Linear correlations between concentrations of total P, Olsen-P, algal avail

关键词： eutrophication freshwater fishery phosphorus fraction water quality

Large-scale virtual machines provisioning in clouds： challenges and approaches

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Frontiers of Computer Science 2016年第1期10卷 2-18页

作者： Zhaoning zhang Dongsheng LI kui WU National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Computer Science Department University of Victoria Victoria V8W 2Y2 Canada

The scale of global data center market has been explosive in recent years. As the market grows, the demand for fast provisioning of the virtual resources to support elas- tic, manageable, and economical computing over the cloud becomes high. Fast provisioning of large-scale virtual ma- chines （VMs）, in particular, is critical to guarantee quality of service （QoS）. In this paper, we systematically review the existing VM provisioning schemes and classify them in three main categories. We discuss the features and research status of each category, and introduce two recent solutions, VMThunder and VMThunder＋, both of which can provision hundreds of VMs in seconds.

关键词： cloud computing IaaS large scale virtual ma-chine provisioning

Surface microlayer enrichment of volatile organic compounds and semi-volatile organic compounds in drinking water source

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Journal of Environmental Sciences 2004年第1期16卷 56-60页

作者： HUANGZhi ZHOUWen YUYa-juan zhangAi-qian HANShuo-kui WANGLian-sheng StateKeyLaboratoryofPollutionControlandSourcesReuse SchooloftheEnvironmentNanjingUniversityNanjing210093China

Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor( EF s) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EF s of SVOC was quite high. Suspension and temperature could affect EF s of SVOC, slim wind and water movement do not destroy enrichment of organic in SM.

关键词： surface microlayer enrichment GC-MS SPE

Characterizations of Centralizable Mappings on Algebras of Locally Measurable Operators

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Acta Mathematica Sinica,English Series 2020年第9期36卷 1039-1048页

作者： Jun HE Guang Yu AN Jian kui LI Wen Hua qian Department of Mathematics Anhui Polytechnic UniversityWuhu 241000P.R.China Department of Mathematics Shaanxi University of Science and TechnologyXi'an 710021P.R.China Department of Mathematics East China University of Science and TechnologyShanghai 200237P.R.China School of Mathematical Sciences Chongqing Normal UniversityChongqing 401331P.R.China

A linear mappingφfrom an algebra A into its bimodule M is called a centralizable mapping at G∈A ifφ(AB)=φ(A)B=Aφ(B)for each A and B in A with AB=*** this paper,we prove that if M is a von Neumann algebra without direct summands of type I1 and type II,A is a*-subalgebra with M■A■LS(M)and G is a fixed element in A,then every continuous(with respect to the local measure topology t(M))centralizable mapping at G from A into M is a centralizer.

关键词： Centralizable mapping centralizer von Neumann algebra locally measurable operator

Discovery of a new family member of arsenic–vanadium polyoxometalates with high catalytic performance for one-pot coupling of CO2, epoxides and amines

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Tungsten 2025年第1期 80-87页

作者： Fang-qian Wang Yin zhang Wei-Wei Wang Mei-qian Fu Hong-Bing Mo Wei-Dong Yu Chao Liu Jun Yan College of Chemistry and Chemical Engineering Central South University Junior Education Department Changsha Normal University School of Science Hunan University of Technology and Business

Arsenic-vanadium polyoxometalates（POMs） represent a family of tremendous potential catalysts owing to their peculiar physical and chemical *** in CO2conversion,using POMs to catalyze the conversion of CO2and epoxide into chemical intermediates is the research ***,A new family number of arsenic-vanadium POMs,[N（CH3）4]4[As8V12O38（H2O）]·2H2O({As8V12O38}),was reported and characterized by single-crystal X-ray diffraction,fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,*** from other allotropicity,{As8V12O38}shows a different structure pattern with an I-43d *** obtained {As8V12O38} was employed as a catalyst for the *** initial catalytic reaction confirmed that {As8V12O38} can catalyze the formation of epoxy carbonate by using 1.01 kPa CO2and epoxide at 70℃.Furtherly,when added amine in the catalytic system,oxazolidinone could be obtained by high yields,which provides an efficient way to convert CO2into profitable ***,a possible catalytic reaction mechanism was proposed by using different characterization analyses.{As8V12O38} first catalyzes the epoxide and CO2to form an epoxy carbonate and then catalyzes epoxy carbonate and benzylamine into oxazolidinone.

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Robust variable normalization least mean p-power algorithm

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Science China(Information Sciences) 2020年第9期63卷 294-302页

作者： kui XIONG Yu zhang Shiyuan WANG College of Electronic and Information Engineering Southwest University Chongqing Key Laboratory of Nonlinear Circuits and Intelligent Information Processing Faculty of Computer and Information Science Southwest University

Dear editor,Adaptive filtering algorithms have been widely applied in system identification, channel equalization, and echo cancellation over the past decades [1–3]. Generally, adaptive filtering algorithms can be ge... 详细信息

关键词： Least mean p-power algorithm variable normalization sigmoid function steady-state performance analysis noise robustness

Research Progress on the Electrical Properties of Gas Hydrate-bearing Sediments

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Acta Geologica Sinica(English Edition) 2023年第3期97卷 816-827页

作者： TAN kui zhang Qi HE Tao Key Laboratory of Orogenic Belts and Crustal Evolution(Ministry of Education) School of Earth and Space SciencesPeking UniversityBeijing 100871China Beijing International Center for Gas Hydrate Peking UniversityBeijing 100871China

Electrical properties are important physical parameters of natural gas hydrate,and,specifically,resistivity has been widely used in the quantitative estimation of hydrate *** are three main methods to study the electrical properties of gas hydrate-bearing sediments:experimental laboratory measurements,numerical simulation,and resistivity *** measurements can be divided into three categories:normal electrical measurement,complex resistivity measurement,and electrical resistivity *** measurements show that the resistivity of hydrate-bearing sediment is affected by many factors,and its distribution as well as the hydrate saturation is not uniform;there is a distinct non-Archie *** numerical method can simulate the resistivity of sediments by changing the hydrate occurrence state,saturation,distribution,***,it needs to be combined with X-ray CT,nuclear magnetic resonance,and other imaging techniques to characterize the porous characteristics of the hydrate-bearing *** well logging can easily identify hydrate layers based on their significantly higher resistivity than the background,but the field data of the hydrate layer also has a serious non-Archie ***,more experimental measurements and numerical simulation studies are needed to correct the parameters of Archie’s formula.

关键词： resource exploration gas hydrate resistivity hydrate saturation numerical simulation well logging Archie's formula

Simulation of denitrification in groundwater from Chaohu Lake Catchment,China

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Water Science and Engineering 2018年第2期11卷 114-119页

作者： Jia-zhong qian Xiu-xuan Wang Lei Ma Long-ping Wang Jian-kui Liu zhang-xian Yang School of Resources and Environmental Engineering Hefei University of TechnologyHefei 230009China Anhui Institute of Geo-Environment Monitoring Hefei 230009China

The eutrophication of Chaohu Lake in China is mainly attributed to nitrate inflow from non-point sources in the lake catchment. In this study,biological nitrate reduction from groundwater in the Chaohu Lake Catchment was investigated under laboratory conditions in a continuous upflow reactor. Sodium acetate served as the carbon source and electron donor. Results showed that a carbon-to-nitrogen(C/N) molar ratio of 3:1 and hydraulic retention time(HRT) of 8 d could achieve the most rapid nitrate nitrogen(NO_3^--N) depletion(from 100 mg/L to 1 mg/L within120 h). This rate was confirmed when field groundwater was tested in the reactor, in which a NO_3^--N removal rate of 97.71% was achieved(from60.35 mg/L to 1.38 mg/L within 120 h). Different levels of the initial NO_3^--N concentration(30, 50, 70, and 100 mg/L) showed observable influence on the denitrification rates, with an overall average NO_3^--N removal efficiency of 98.25% at 120 h. Nitrite nitrogen(NO_2^--N)accumulated in the initial 12 h, and then kept decreasing, until it reached 0.0254 mg/L at 120 h. Compared with the initial value, there was a slight accumulation of 0.04 mg/L for the ammonia nitrogen(NH4-N) concentration in the effluent, which is, however, less than the limit *** results can provide a reference for evaluating performance of denitrification in situ.

关键词： Chaohu Lake Catchment Denitrification Eutrophication Nitrate Wetland

Certified defense against patch attacks via mask-guided randomized smoothing

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Science China(Information Sciences) 2022年第7期65卷 86-97页

作者： kui zhang Hang ZHOU Huanyu BIAN Weiming zhang Nenghai YU School of Cyber Science and Technology University of Science and Technology of China School of Computer Science Simon Fraser University

The adversarial patch is a practical and effective method that modifies a small region on an image, making DNNs fail to classify. Existing empirical defenses against adversarial patch attacks lack theoretical analysis and are vulnerable to adaptive attacks. To overcome such shortcomings, certified defenses that provide a guaranteed classification performance in the face of strong unknown adversarial attacks are proposed. However, on the one hand, existing certified defenses either have low clean accuracy or need specified architecture, which is not robust enough. On the other hand, they can only provide provable accuracy but ignore the relationship to the number of perturbations. In this paper, we propose a certified defense against patch attacks that provides both the provable radius and high classification accuracy. By adding Gaussian noises only on the patch region with a mask, we prove that a stronger certificate with high confidence can be achieved by randomized smoothing. Furthermore, we design a practical scheme based on joint voting to find the patch with a high probability and certify it effectively. Our defense achieves 86.4%clean accuracy and 71.8% certified accuracy on CIFAR-10 exceeding the maximum 60% certified accuracy of existing methods. The clean accuracy of 67.8% and the certified accuracy of 53.6% on ImageNet are better than the state-of-the-art method, whose certified accuracy is 26%.

关键词： certified defense adversarial patch patch localization randomized smoothing joint voting

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