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Genotoxicity of drinking water treated with different disinfectants and effects of disinfection conditions detected by umu-test

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Journal of Environmental Sciences 2017年第6期29卷 36-44页

作者： Xuebiao Nie Wenjun liu Liping Zhang qing liu Division of Drinking Water Safety School of EnvironmentTsinghua UniversityBeijing 100084China

The genotoxieity of drinking water treated with 6 disinfection methods and the effects of disinfection conditions were investigated using the urea-test The pretreatment procedure of samples for the urea-test was optimized for drinking water analysis. The results of the urea-test were in good correlation with those of the Ames-test The genotoxicity and production of haloacetic acids （HAAs） were the highest for chlorinated samples. UV ＋ chloramination is the safest disinfection method from the aspects of genotoxicity, HAA production and inactivation effects. For chloramination, the effects of the mass ratio of C12 to N of chloramine on genotoxicity were also studied. The changes of genotoxicity were different from those of HAA production, which implied that HAA production cannot represent the genotoxic potential of water. The genotoxicity per chlorine decay of chlorination and chloramination had similar trends, indicating that the reaction of organic matters and chlorine made a great contribution to the genotoxicity. The results of this study are of engineering significance for optimizing the operation of waterworks.

关键词： CenotoxicityDrinking waterChlorineUVDisinfectionumu-test

Selective reduction of carbon dioxide into amorphous carbon over activated natural magnetite

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 231-237页

作者： Zhong-qing liu Jian Zheng Yi Wang Xu liu School of Chemical Engineering Sichuan UniversityChengdu 610065China

Natural magnetite formed by the isomorphism substitutions of transition metals,including Fe,Ti,Co,etc.,was activated by mechanical grinding followed by H2 *** temperature-programmed reduction of hydrogen(H2-TPR)and temperature-programmed surface reaction of carbon dioxide(CO2-TPSR)were carried out to investigate the processes of oxygen loss and CO2 *** samples were characterized by X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM),and energy-dispersive X-ray spectroscopy(EDS).The results showed that the stability of spinel phases and oxygen-deficient degree significantly increased after natural magnetite was mechanically milled and reduced in H2 ***,the activity and selectivity of CO2 reduction into carbon were *** deposited carbon on the activated natural magnetite was confirmed as *** amount of carbon after CO2 reduction at 300°C for 90 min over the activated natural magnetite was 2.87wt%higher than that over the natural magnetite.

关键词： carbon dioxide reduction natural magnetite isomorphism substitutions grind activation oxygen-deficient degree amorphous carbon

A damage-coupled multi-axial time-dependent low cycle fatigue failure model for SS304 stainless steel at high temperature

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Acta Metallurgica Sinica(English Letters) 2011年第2期24卷 169-174页

作者： Yujie liu qing GAO Guozheng KANG School of Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China

Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ？ C, and in the frame of unified visoco-plastic cyclic constitutive model and continuum damage mechanics theory, the damage-coupled multi-axial time-dependent constitutive model and fatigue failure model were proposed. In the model, the evolution equation of damage was introduced in and the time-dependent effects, e.g. holding time, loading rate, were taken into account. The model was applied to the simulation of whole-life cyclic deformation behaviors and prediction of LCF life for SS304 stainless steel in multiaxial time-dependent low cycle fatigue tests. It is shown that the simulated results agree well with experimental ones.

关键词： SS304 stainless steel Constitutive model Low cycle fatigue Failure model Damage-coupled High temperature

THE CHARACTERISTICS AND ESTIMATION OF FLOW THROUGH A SINGLE ROUGH-WALLED FRACTURE

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Journal of Hydrodynamics 2012年第3期24卷 315-322页

作者： liu qing-quan FAN Hong-guang Laboratory-of Environmental Mechanics Institute of Mechanics Chinese Academy of Sciences Beijing 100190China

The flow through a single fracture is numerically studied by means of the Fluent Software. The results show that the roughness of the fracture significantly affects the hydraulic conductivity in the fracture as compared with the cubic law model widely used to describe the flow between two smooth parallel plates. A new model is proposed in this paper, the non-symmetric sinusoidal fracture model, to simulate the flow in a real fracture. This model involves two sinusoidal-varying walls with different phases to replace the flat planes in the cubic law model. The relationships between the effective hydraulic apertures and the phase retardation for different relative amplitudes and wavelengths are numerically investigated. A simple expression of the effective hydraulic aperture of the fracture is obtained, together with the law of the effective hydraulic aperture against the amplitude, the phase retardation and the wavelength of two sinusoidal-varying walls.

关键词： fracture seepage cubic law effective hydraulic aperture non-symmetric sinusoidal fracture

Adjustable entropy function method for support vector machine

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Journal of Systems Engineering and Electronics 2008年第5期19卷 1029-1034页

作者： Wu qing liu Sanyang Zhang Leyou Dept. of Mathematical Sciences Xidian Univ. Xi'an 710071 P. R. China

Based on KKT complementary condition in optimization theory, an unconstrained non-differential optimization model for support vector machine is proposed. An adjustable entropy function method is given to deal with the proposed optimization problem and the Newton algorithm is used to figure out the optimal solution. The proposed method can find an optimal solution with a relatively small parameter p, which avoids the numerical overflow in the traditional entropy function methods. It is a new approach to solve support vector machine. The theoretical analysis and experimental results illustrate the feasibility and efficiency of the proposed algorithm.

关键词： optimization support vector machine adjustable entropy function Newton algorithm.

Operation of three parallel AN/AO processes to enrich denitrifying phosphorus removing bacteria for low strength wastewater treatment

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Journal of Environmental Sciences 2006年第3期18卷 433-438页

作者： XIA Si-qing liu Hong-bo State Key Lab of Pollution Control and Resource Reuse Tongji University Shanghai 200092 China.

Three parallel anaerobic-anoxic/anaerobic-aerobic （AN/AO） processes were developed to enrich denitrifying phosphorus removal bacteria （DPB） for low strength wastewater treatment. The main body of the parallel AN/AO process consists of an AN （anaerobic-anoxic） process and an AO （anaerobic-aerobic） process. In the AO process, the common phosphorus accumulating organisms （PAOs） was dominate, while in the AN process, DPB was dominate, The volume of anaerobic zone（Vana）：anoxie zone（Vano）： aerobic zone （Vaer） for the parallel AN/AO process is 1：1：1 in contrast with a Vana：Vaer and Vano：Vaer of 1：2 and 1：4 for a traditional biological nutrient removal process （BNR）. Process 3 excels in the 3 processes on the basis of COD, TN and TP removal. For 4 month operation, the effluent COD concentration of process 3 did not exceed 60 mg/L; the effluent TN concentration of process 3 was lower than 15 mg/L; and the effluent TP concentration of process 3 was lower than 1 mg/L.

关键词： parallel AN/AO process denitrifying phosphorus removing bacteria (DPB) low strength wastewater biological nutrientremoval (BNR)

Synthesis and Structural Study of a N-Heterocyclic Carbene Trinuclear Silver(Ⅰ)Complex

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Chinese Journal of Structural Chemistry 2016年第2期35卷 313-318页

作者： liu Jun HUO Ran WEI qing ZHAO Zhi-Xiang liu qing-Xiang Tianjin Key Laboratory of Structure and Performance for Functional Molecules Key Laboratory of Inorganic-organic Hybrid Functional Material ChemistryMinistry of Education College of ChemistryTianjin Normal UniversityTianjin 300387China

The bis-benzimidazolium salt bis[2-（N-ethylbenzimidazoliumyl）ethyl]amine hexafluorophosphate（LH2·（PF6）2） and its N-heterocyclic carbene silver（Ⅰ） complex[L2Ag3]（PF6）3（1）have been prepared and *** complex 1,a trinuclear silver（Ⅰ） architecture is formed by two tridentate ligands and three silver（I） atoms,in which one 12- and two 7-membered rings are *** the crystal packing of 1,1D chain and 2D supramolecular layer are formed via intermolecular weak interactions,including π…π interactions and C-H…π ***,the fluorescence emission spectra of LH2-（PF6）2 and 1 are described.

关键词： carbene silver(I) complex bis-benzimidazolium salt

(K,Na)NbO_(3)-based lead-free ceramics with enhanced temperature-stable piezoelectricity and efficient red luminescence

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Journal of Advanced Ceramics 2023年第2期12卷 373-385页

作者： qing liu Er PAN Fucai liu Jing-Feng LI School of Optoelectronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

There has been a surge of research interest in the promising lead-free potassium-sodium niobate(KNN)-based ceramics,applications of which could be significantly promoted by improving thermal stability of ***,endowing the KNN-based ceramics with photoluminescence property by rare-earth-ion doping can make them more completive lead-free counterparts in potential applications such as novel multifunctional sensing ***,a novel KNN-based ceramic material doped with Eu was elaborately designed to simultaneously obtain enhanced temperaturestable piezoelectricity and good luminescence *** the introduction of diffused phase transition and the modulation of unit cell distortion,a large piezoelectric strain coefficient(d^(*)_(33))with a small variation(590±59 pm/V)over a wide temperature range(from room temperature to 110℃)was *** optimal composition also exhibited a considerable piezoelectric coefficient(d_(33))with small fluctuation(330±33 pC/N)from 20 to 80℃.In addition to the enhanced temperature-stable piezoelectricity,the luminescence of these ceramics was slightly enhanced with the elevation of BaZrO_(3)(BZ)doping contents,which could be attributed to the increased compositional disorder and the decreased unit cell distortion of the matrix ***,an optical characteristic was more prominent at ultra-low *** work unprecedentedly provides a novel paradigm for the design of multifunctional KNN-based ceramics with enhanced temperature-stable piezoelectricity and good luminescence property,revealing the great potential of the rare-earth-element-doped KNN material for future applications in the novel multifunctional devices.

关键词： piezoelectric thermal stability rare-earth lead-free potassium-sodium niobate(KNN)

Eigenvalues and Diameter

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1107-1114页

作者： Hui qing liu Mei LU School of Mathematics and Computer Science Hubei University Wuhan 430062 P. R. China Department of Mathematical Sciences Tsinghua University Beijing 100084 P. R. China

Let G be a connected graph of order n. The diameter of a graph is the maximum distance between any two vertices of G. In this paper, we will give some bounds on the diameter of G in terms of eigenvalues of adjacency m... 详细信息

关键词： Graph Laplacian matrix adjacency matrix diameter