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Arsenic species analysis in porewaters and sediments using hydride generation atomic fluorescence spectrometry

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Journal of Environmental Sciences 2006年第5期18卷 995-999页

作者： LIAO Meng-xia DENG tian-long College of Materials Chemistry and Chemical Engineering Chengdu University of Technology Chengdu 610059 China Qinghai Institute of Salt Lakes Chinese Academy of Sciences Xining 810008 China

It was observed that the atomic fluorescence emission due to signal during the determination of As（Ⅲ） in the mixture of As（Ⅲ） and As（V） could has a 10% to 40% of fluorescence emission As（V）. Besides, interferes from heavy metals such as Pb（Ⅱ）, Cu（Ⅱ） can cause severe increase of the signals as compared to the insignificant effects caused by Cd（Ⅱ）, Zn（Ⅱ）, Mn（Ⅱ） and Fe（Ⅲ）. On the basis of further studies, the masking agent of 8-hydroxyquinoline was used as an efficient agent to eliminate interference of As（V） emission and the heavy metal of Cu^2＋ and Pb^2＋ in the measurements of arsenic species, After a series standard additions and CRM researches, a sensitive and interference-free analytical procedure was developed for the speciation of arsenic in samples of porewaters and sediments in Poyang Lake, China.

关键词： arsenic speciation 8-hydroxyquinoline porewaters sediments Poyang Lake

MicroRNAs of microglia： wrestling with central nervous system disease

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Neural Regeneration Research 2018年第12期13卷 2067-2072页

作者： Xiao-Hua Wang tian-long Wang Department of Anesthesiology Xuanwu Hospital Capital Medical University Beijing China Institute of Geriatrics Beijing China National Clinical Research Center for Geriatric Disorders Beijing China

Microglia serve as brain-resident myeloid cells that affect cerebral development, ischemia, neurodegeneration, and neuro-viral infection. MicroRNAs play a key role in central nervous system disease through post-transcriptional regulation. Indeed, evidence shows that microRNAs are one of the most important regulators mediating microglial activation, polarization, and autophagy, and subsequently affecting neuroinflammation and the outcome of central nervous system disease. In this review, we provide insight into the function of microRNAs, which may be an attractive strategy and influential treatment for microglia-related central nervous system dysfunction. Moreover, we comprehensively describe how microglia fight against central nervous system disease via multiple functional microRNAs.

关键词： microglia neurodegeneration central nervous system disease microRNAs activation polarization autophagy neural regeneration

The growth of H-harmonic functions on the Heisenberg group

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Science China Mathematics 2014年第4期57卷 795-806页

作者： LIU HaiRong tian long YANG XiaoPing School of Science Nanjing University of Science and Technology School of Science Nanjing Forestry University

We discuss the relationship between the frequency and the growth of H-harmonic functions on the Heisenberg ***,we prove that an H-harmonic function must be a polynomial if its frequency is globally ***,we show that a class of H-harmonic functions are homogeneous polynomials provided that the frequency of such a function is equal to some constant.

关键词： Heisenberg group H-harmonic function frequency

A class of transient acceleration models consistent with Big Bang cosmology

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Research in Astronomy and Astrophysics 2014年第2期14卷 129-138页

作者： tian-long Zu Jie-Wen Chen Yang Zhang Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China

Is it possible that the current cosmic accelerating expansion will turn into a decelerating one？ Can this transition be realized by some viable theoretical model that is consistent with the standard Big Bang cosmology？ We study a class of phenomeno- logical models with a transient acceleration, based on a dynamical dark energy with a very general form of equation of state Pde = αPde -- βpdem. It mimics the cosmolog- ical constant αde → const for a small scale factor a, and behaves as a barotropic gas with pde → α-3（α＋1） with α 〉 0 for large a. The cosmic evolution of four models in the class has been examined in detail, and all yield a smooth transient acceleration. Depending on the specific model, the future universe may be dominated by either dark energy or by matter. In two models, the dynamical dark energy can be explicitly real- ized by a scalar field with an analytical potential V（O）. Moreover, a statistical analysis shows that the models can be as robust as ACDM in confronting the observational data of Type Ia supernovae, cosmic microwave background （CMB） and baryon acoustic os- cillation. As improvements over previous studies, our models overcome the problem of over-abundance of dark energy during early eras, and satisfy the constraints on dark energy from WMAP observations of CMB.

关键词： cosmology: theory -- methods: analytical

Reconfigurable,graphene-coated,chalcogenide nanowires with a sub-10-nm enantioselective sorting capability

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Microsystems & Nanoengineering 2018年第1期4卷 337-344页

作者： Tun Cao long tian Huawei Liang Kai-Rong Qin Department of Biomedical Engineering Dalian University of TechnologyDalianChina Shenzhen Key Laboratory of Laser Engineering College of Optoelectronic EngineeringShenzhen UniversityShenzhenChina

Chiral surface plasmon polaritons(SPPs)produced by plasmonic nanowires can be used to enhance molecular spectroscopy for biosensing ***,the switchable stereoselectivity and detection of various analytes are limited by a lack of switchable,chiral *** both finite-element method simulations and analytic calculations,we present a graphene-coated chalcogenide(GCC)nanowire that produces mid-infrared,chiral *** chiral SPPs can be reversibly switched between“on”(transparent)and“off”(opaque)by non-volatile structural state transitions in the dielectric constants of the chalcogenide glass ***,by controlling the Fermi energy of the graphene-coating layer,the nanowire can output either non-chiral or chiral SPPs.A thermal-electric model was built to illustrate the possibility of ultrafast on/off switching of the SPPs at the terminus of the ***,we show that a selective,lateral sorting of sub-10-nm enantiomers can be achieved via the GCC *** nanoparticles with opposite handedness experience transverse forces that differ in both their sign and *** design may pave the way for plasmonic nanowire networks and tunable nanophotonic devices,which require the ultrafast switching of SPPs,and provide a possible approach for a compact,enantiopure synthesis.

关键词： synthesis chiral Chiral

High-temperature fatigue behavior of 15CrNbTi ferritic stainless steel

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Journal of Iron and Steel Research International 2019年第3期26卷 285-291页

作者： tian-long Liu Li-jia Chen Hong-yun Bi Xin Che School of Materials Science and Engineering Shenyang University of Tech no logy Shenyang 110870 Liaoning. China Baosteel Central Research Institute Baosteel Co..Ltd.Shanghai 201900China

In order to investigate the high-temperature fatigue and fatigue-creep behavior of 15CrNbTi ferritic stainless steel at 800°C,fatigue tests without holding time in laboratory air and with 10 s holding time induced at maximum cyclic stress under argon atmosphere were conducted on an electrohydraulic servo fatigue testing *** addition,the morphologies of fatigue fracture surfaces were observed,and the precipitates and dislocation substructures were *** experimental results show that the fatigue limit of 15CrNbTi ferritic stainless steel is 30 MPa at 800°*** fatigue life of the experimental steel obviously decreases if holding time of 10 s is introduced at maximum cyclic *** two test conditions,the fatigue cracks transgranularly initiate at the free surface of fatigue specimens and then propagate in a transgranular *** is dem on strated that three kinds of precipitates inclu ding(Nb,Ti)C phase,Fe2Nb phase and Fe3Nb3C phase can be observed in 15CrNbTi ferritic stainless steel,and the Fe2Nb and Fe3Nb3C phases are mainly precipitated during the fatigue *** the fatigue deformation area,both dislocation tangles and dislocation arrays are ***,the sub-grains which form during the cycling deformation with holding time of 10 s are also ***,the formation of sub-grains leads to the deterioration of the fatigue life of 15CrNbTi steel.

关键词： Ferritic stainless steel-High-temperature fatigue Holding time Fatigue fracture Precipitate Dislocation substructure

Suppression of Vortex-Induced Vibration Caused by A Terebridae-Inspired Cylinder with Different Helical Angles

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China Ocean Engineering 2024年第5期38卷 739-754页

作者： YU Qi-dong MAO Zhao-yong tian Wen-long WANG Wei Unmanned System Research Institute Northwestern Polytechnical UniversityXi’an 710072China School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an 710072China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

Biomimetic design has recently received widespread *** by the Terebridae structure,this paper provides a structural form for suppressing vortex-induced vibration(VIV)*** different structural forms are shown,including the traditional smooth cylinder(P0),and the Terebridae-inspired cylinder with the helical angle of 30°(P_(30)),60°(P_(60)),and 90°(P_(90)).Computational fluid dynamics(CFD)method is adopted to solve the flow pass the Terebridae-inspired structures,and the vibration equation is solved using the Newmark-β*** results show that for P_(30),P_(60) and P_(90),the VIV responses are effectively suppressed in the lock-in region,and P_(60) showed the best VIV suppression *** transverse amplitude and the downstream amplitude can be reduced by 82.67%and 91.43%respectively for P_(60) compared with that for P0,and the peak of the mean-drag coefficient is suppressed by 53.33%.The Q-criterion vortices of P_(30),P_(60),and P_(90) are destroyed,with irregular vortices *** is also found that the boundary layer separation is located on the Terebridae-inspired *** twisted ribs cause the separation point to constantly change along the spanwise direction,resulting in the development of the boundary layer separation being completely *** strength of the wake flow is significantly weakened for the Terebridae-inspired cylinder.

关键词： vortex-induced vibration(VIV) Terebridae cylinder suppression helical angle

Magnetic Resonance Urography and X-ray Urography Findings of Congenital Megaureter

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Chinese Medical Sciences Journal 2011年第2期26卷 103-108页

作者： tian-ran Li Xiang-ke Du tian-long Huo Department of Radiology Peking University People＇s Hospital Beijing 100044 China

Objective To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease. Methods Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were analyzed, and image findings of congenital megaureter were summarized. Elscint Prestig 2.0T superconductive magnetic resonance urography （MRLI） with conventional sequence （spin-echo, T 1W1560 ms/16 ms; fast spin-echo, T2WI 9600 ms/96 ms） was performed. Raw data were acquired with fast spin-echo sequence from heavy T2-weighted image （9600 ms/120 ms）. Post-processing method of MRH was the maximum in- tensity projection with three-dimensional reconstruction in the workstation. Intravenous pyelography （IVP） was conducted, in which X-ray films were taken 7 minutes, 15 minutes, and 30 minutes after injecting contrast agent, except that in 2 patients the films were taken delayed at 60 and 90 minutes. X-ray retrograde pyelography was performed on 2 patients, successful in one but failed in the other. Results The dilated ureter showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in conventional MRI. The mass wall was intact, uniform in thickness, and showing hy- pointensity on Tl-weighted and T2-weighted images. The MRH images showed a retroperitoneal mass appearing as an elongated tubular cystic structure spreading from kidney to bladder. MRLI also revealed dilated calices and renal pelvis, pelviureteric obstruction, and renal duplication. The main signs of congenital megaureter in X-urography was significant dilatation of ureter, or normal renal pelvis with ureter dilatation, hydronephrosis, deformity, and displacement. Conclusions MRH with X-urography could visualize the characteristics of congenital megaureter, including the dilation of renal pelvis and ureter, calculi, urinary tract duplication, and stenosis location. The two techniques can complement each other in disease diagnosis and provide more detailed information for

关键词： congenital megaureter magnetic resonance urography intravenous pyelo-graphy

Bats as the main prey of wintering long-eared owl(Asio otus)in Beijing:Integrating biodiversity protection and urban management

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Integrative Zoology 2015年第2期10卷 216-226页

作者： long tian Xuwei ZHOU Yang SHI Yumin GUO Weidong BAO Department of Zoology Beijing Forestry University College of Nature Conservation Beijing Forestry UniversityBeijingChina Beijing Wildlife Rescue and Rehabilitation Center BeijingChina

The loss of biodiversity from urbanized areas is a major environmental problem challenging policy-makers throughout the *** to this problem are urgently required in *** carried out a case study of wintering long-eared owls(Asio otus)and their main prey to illustrate the negative effects of urbanization combined with ineffective conservation of biodiversity in *** monitoring of owl numbers at two roosting sites from 2004 to 2012 showed that the owl population had fallen rapidly in metropolitan *** of pellet contents identified only seven individuals of two species of *** majority of mammalian prey comprised four bat and seven rodent species,making up 29.3%and 29.5%of the prey items,*** composition varied significantly among years at the two sample *** the urban site the consumption of bats and rodents declined gradually over time,while predation on birds *** contrast,at the suburban site the prey composition showed an overall decrease in the number of bats,a sharp increase and a subsequent decrease in bird prey,and the number of rodent prey fell to a low *** development of real estate and inadequate greenfield management in city parks resulted in negative effects on the bird and small mammal habitat of urban areas in *** suggest that measures to conserve biodiversity should be integrated into future urban planning to maintain China’s rich biodiversity while also achieving sustainable economic development.

关键词： biodiversity reduction city planning diet composition long-eared owl urbanization