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Water Science and Engineering 2019年第4期12卷 293-297页

作者： Xi-zhi niu Department of Chemical and Environmental Engineering and Arizona Laboratory for Emerging Contaminants University of Arizona

Two kinetic models were established for conservative estimates of photodegradation rates of contaminants under sunlight irradiation,in particular for wastewater stabilisation ponds and clarifiers in conventional wastewater treatment *** two models were designated for(1)contaminants with high photolytic rates or high photolytic quantum yields,whose photodegradation is unlikely to be enhanced by aquatic photosensitisers;and(2)contaminants withstanding direct photolysis in sunlit waters but subjected to indirect *** effortlessly intelligible prediction procedure involves sampling and analysis of real water samples,simulated solar experiments in the laboratory,and transfer of the laboratory results to realise water treatment using the prediction *** similar models have been widely used for laboratory studies,this paper provides a preliminary example of translating laboratory results to the photochemical fate of contaminants in real waters.

关键词： Sunlight irradiation Photodegradation Contaminants Stabilisation ponds Solar water treatment

Purification and studies on characteristics of cholinesterases from Daphnia magna

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第4期14卷 325-335页

作者： Yan-xia YANG Li-zhi niu Shao-nan LI Institute of Pesticide and Environmental Toxicology College of Agriculture and BiotechnologyZhejiang University

Due to their significant value in both economy and ecology,Daphnia had long been employed to investigate in vivo response of cholinesterase(ChE) in anticholinesterase exposures,whereas the type constitution and property of the enzyme remained unclear.A type of ChE was purified from Daphnia magna using a three-step procedure,i.e.,Triton X-100 extraction,ammonium sulfate precipitation,and diethylaminoethyl(DEAE)-Sepharose Fast-Flow *** to sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE),molecular mass of the purified ChE was estimated to be 84 *** on substrate studies,the purified enzyme preferred butyrylthiocholine iodide(BTCh) [with maximum velocity(Vmax)/Michaelis constant(Km)=8.428 L/(min·mg protein)] to acetylthiocholine iodide(ATCh) [with V max /Km =5.346 L/(min·mg protein)] as its *** of the purified enzyme was suppressed by high concentrations of either ATCh or *** studies showed that the purified enzyme was more sensitive towards inhibition by tetraisopropylpyrophosphoramide(iso-OMPA) than by 1,5-bis(4-allyldimethylammoniumphenyl) pentan-3-one dibromide(BW284C51).Result of the study suggested that the purified ChE was more like a type of pseudocholinesterase,and it also suggested that Daphnia magna contained multiple types of ChE in their bodies.

关键词： Crustacea Pseudocholinesterase Cholinesterase Substrate preference Selective inhibitors

Microstructural adjustments and mechanical properties of a cold-rolled biomedical near β-Ti alloy sheet

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Rare Metals 2018年第10期37卷 846-851页

作者： Xi-Qun Ma Hong-zhi niu Zhen-Tao Yu Sen Yu Chang Wang Northwest Institute for Nonferrous Metal Research Xi'an 710016 China School of Materials Science and Engineering Northeastern University Shenyang 110819 China

In this study, microstructural adjustments and mechanical properties of a cold-rolled near β-type alloy Ti-25Nb-3Zr-3Mo-2Sn （wt%） sheet were investigated. Microstructures and phase transformation products strongly depended on aging temperatures. Solution treatments within single β-phase field removed the stress-induced at martensites and produced a few new lath-shaped ones, but metastable β phase still dominated. This is exactly the reason why current alloy exhibits the lowest modulus （54 GPa） and best elongation to fracture （39 %）, but the worst yield strength of only 340 MPa, at solutiontreated state. A fairly large number of ellipsoidal ω phase nanoparticles precipitated throughout parent β phase during aging at 380℃. These ω nanoparticles possess remarkable strengthening effect, but deteriorate ductility seriously. A novel post-aging process was proposed to remove brittle ω phase. By contrast, aging at 450 ℃ resulted in sufficient precipitation of fine needle-like α phase. This brought about the best combination of high yield strength （770 MPa） and moderate elastic modulus （75 GPa） and good elongation （15 %） for biomedical implants.

关键词： Near β-Ti alloy Microstructures Phase transformation Mechanical properties

Channel estimation based on distributed compressed sensing in amplify-and-forward relay networks

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The Journal of China Universities of Posts and Telecommunications 2010年第5期17卷 44-49页

作者： WANG Dong-hao niu Kai HE zhi-qiang TIAN Bao-yu School of Information and Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

In orthogonal frequency-division multiplexing （OFDM） amplify-and-forward （AF） relay networks,in order to exploit diversity gains over frequency-selective fading channels,the receiver needs to acquire the knowledge of channel state information （CSI）.In this article,based on the recent methodology of distributed compressed sensing （DCS）,a novel channel estimation scheme is *** joint sparsity model 2 （JSM-2） in DCS theory and simultaneous orthogonal matching pursuit （SOMP） are both introduced to improve the estimation performance and increase the spectral *** results show that compared with current compressed sensing （CS） methods,the estimation error of our scheme is reduced dramatically in high SNR region while the pilot number is still kept small.

关键词： channel estimation DCS relay networks SOMP

EXPERIMENTAL INVESTIGATION OF THE FAILURE OF CASCADE LANDSLIDE DAMS

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Journal of Hydrodynamics 2012年第3期24卷 430-441页

作者： niu zhi-pan XU Wei-lin LI Nai-wen XUE Yang CHEN Hua-yong State key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China Key Laboratory-of Mountain Hazards and Land Surface Processes and Institute of Mountain Hazards andEnvironment Chinese Academy of Sciences Chengdu 610041 China

This paper presents results of model tests for the landslide dam failure of a single dam and cascade dams in a sloping channel. The dams were designed to be regular trapezoid with fine sand. A new measuring method named the labeled line locating method was used to digitalize the captured instantaneous pictures. Under two different inflow discharges, the morphological evolution and the flow patterns during one dam failure and the failure of cascade dams were investigated. The results indicate that when the inflow discharge is large, the deformation pattern of the downstream dam is similar to that of the upstream dam, and both dams are characterized with the overtopping scour throughout the dam failure process. When the inflow discharge is small, the upstream dam is scoured mainly through a sluice slot formed by the longitudinal incision, and the downstream dam is characterized with the overtopping scour. The data set presented in this paper can be used for the validation of numerical models and provide a reference for the flood risk management of cascade landslide dams.

关键词： labeled lines locating method inflow discharge cascade landslide dam failure overtopping sloping flume

Analysis of solute preferential transport in a dark coniferous forest ecosystem of Gongga Mountain,Sichuan Province,southwestern China

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Forestry Studies in China 2010年第1期12卷 14-20页

作者： niu Jian-zhi YU Xin-xiao ZHANG zhi-qiang Key Laboratory of Soil and Water Conservation ＆ Desertification Combating of the Ministry of Education School of Soil and WaterConservation Beijing Forestry University Beijing 100083 P. R. China

We selected a dark coniferous forest ecosystem of Gongga Mountain in the upper reaches of the Yangtze River as our research area to study the preferential flow and solute preferential transport by adding the tracers KNO3 and KBr to the self-made soil column equipment in different ways to examine density and volume changes of inflows and outflows of a mass input （impulse input） and a stable, well-distributed input （step input））. The results showed that this dark coniferous forest ecosystem of Gongga Mountain is a typical area of preferential flow and solute preferential transport, a process that can be classified into five parts. A great amount of solute was transported at high speed as the result of preferential flow in the soil and caused the density of the solute in both deep water and in groundwater to rise rapidly, which definitely increased pollution in the deep soil layer.

关键词： Gongga Mountain dark coniferous forest ecosystem preferential flow preferential transport solute transport,breakthrough curve water quality

Evaluation of phytoextracting cadmium and lead by sunflower,ricinus,alfalfa and mustard in hydroponic culture

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Journal of Environmental Sciences 2007年第8期19卷 961-967页

作者： niu zhi-xin SUN Li-na SUN Tie-heng LI Yu-shuang WANG Hong Institute of Applied Ecology Chinese Academy of Sciences Shen yang 110016 China Shenyang University Key Laboratory of Environmental Engineering Shenyang 110044 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China

Soil contaminated with heavy metals cadmium （Cd） and lead （Pb） is hard to be remediated. Phytoremediation may be a feasible method to remove toxic metals from soil, but there are few suitable plants which can hyperaccumulate metals. In this study, Cd and Pb accumulation by four plants including sunflower （Helianthus annuus L.）, mustard （Brassicajuncea L.）, alfalfa （Medicago sativa L.）, ricinus （Ricinus communis L.） in hydroponic cultures was compared. Results showed that these plants could phytoextract heavy metals, the ability of accumulation differed with species, concentrations and categories of heavy metals. Values of BCF （bioconcentration factor） and TF （translocation factor） indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals. Changes on the biomass of plants, pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures. Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals, such as pH and Eh regulations, and so forth.

关键词： phytoextraction heavy metals plants cadmium lead

Sliding Mode Control of Hydraulic Pressure in Electro-Hydraulic Brake System Based on the Linearization of Higher-Order Model

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Fluid Dynamics & Materials Processing 2020年第3期16卷 513-524页

作者： Qiping Chen Haoyu Sun Ning Wang zhi niu Rui Wan Key Laboratory of Conveyance and Equipment Ministry of Education East China Jiaotong UniversityNanchang330013China

The possibility to enhance the stability and robustness of electrohydraulic brake(EHB)systems is considered a subject of great importance in the automotive *** such a context,the present study focuses on an actuator with a four-way sliding valve and a hydraulic cylinder.A 4-order nonlinear mathematical model is introduced *** the linearization of the feedback law of the high order EHB model,a sliding mode control method is proposed for the hydraulic *** hydraulic pressure tracking controls are simulated and analyzed by MATLAB/Simulink soft considering separately different conditions,i.e.,a sine wave,a square wave and a square wave with superimposed sine *** results show that the proposed strategy can track the target within 0.25 s,and the mean observed error is less than 1.2 ***,with such a strategy,faster response and less overshoot are possible,which should be regarded as significant advantages.

关键词： EHB hydraulic pressure feedback linearization sliding mode control

Molting process revealed by the detailed expression profiles of RXR1/RXR2 and mining the associated genes in a spider mite, Panonychus citri

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Insect Science 2022年第2期29卷 430-442页

作者： Gang Li Xun-Yan Liu Guy Smagghe Jin-zhi niu Jin-Jun Wang Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionInternational Joint Laboratory of China-Belgium on Sustainable Crop Pest ControlAcademy of Agricultural SciencesSouthwest UniversityChongqingChina Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions Institute of EntomologyGuizhou UniversityGuiyangChina Department of Plants and Crops Faculty of Bioscience EngineeringGhent UniversityGhentBelgium

Spider mites have one ecdysone receptor(EcR)and multiple retinoid X receptors(RXRs).However,the function of these RXRs in spider mite development is ***,we screened the expression dynamics of two PcRXR isoforms at 4 h intervals in the deutonymphal stage of Panonychus *** results showed that PcEcR had an expression pattern similar to that of *** PcRXR1,its expression remained at a certain high level,when there was a decrease of both PcEcR and *** situ hybridization showed that PcRXR2 was detected in the central nervous mass,while the ecdysteroid biosynthesis gene PcSpo was mainly expressed at the edge of the central nervous ***-based silencing of PcRXR1 or PcRXR2 showed the same phenotype as in mites with that of silencing ***,RNA-seq was used to mine the genes associated with the expression dynamics of PcRXR1 or PcRXR2,which revealed that the heterodimer of EcR-RXR2 in spider mites might be linked with the cell autophagy and tissue remodeling during apolysis,and RXR1 might be linked with new epicuticle and exocuticle secretion during *** together,these results increase our understanding of the regulation mechanism of ecdysteroid signal pathway in spider mite development.

关键词： ecdysone receptor(EcR) in situ hybridization retinoid X receptors RNA interference RNA-seq

Cloning and functional characterization of two peptidoglycan recognition protein isoforms (PGRP-LC) in Bactrocera dorsalis (Diptera: Tephritidae)

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Journal of Integrative Agriculture 2020年第12期19卷 3025-3034页

作者： WEI Dong WANG Zhe XU Hui-qian niu Jin-zhi WANG Jin-jun Chongqing Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionSouthwest UniversityChongqing 400715P.R.China State Cultivation Base of Crop Stress Biology for Southern Mountainous Land Academy of Agricultural SciencesSouthwest UniversityChongqing 400715P.R.China

The innate immune system of insects is the front line of self-defense against pathogen invasion. Peptidoglycan recognition proteins (PGRPs) are important components and play key roles in insect immune systems by recognizing peptidoglycan (PGN) in bacterial cell walls. We characterized two isoforms of the PGRP-LC gene, BdPGRP-LCa and BdPGRP-LCb, from Bactrocera dorsalis (Hendel), an important fruit and vegetable pest worldwide. These two isoforms contain an open reading frames of 1 668 bp and 1 731 bp, encoding a protein of 555 and 576 amino acids, respectively. Quantitative real-time PCR results showed that both transcripts were prominently expressed in midgut and fat body of B. dorsalis adult. Inoculation of pathogens showed that both isoforms actively responded to Escherichia coli PGN. We also observed a light response to Staphylococcus aureus PGN. Upon Beauveria bassiana inoculation, the expression of BdPGRP-LCa was enhanced, but the expression of BdPGRP-LCb was suppressed. Suppression of both transcripts by RNA interference led to increased mortality of flies challenged by E. coli, indicating that the two isoforms are involved in sensing Gram-negative bacterial infections.

关键词： oriental fruit fly innate immunity PGRPs Gram-negative bacterium