检索结果-南通市图书馆

Wave-current bottom shear stresses and sediment re-suspension in the mouth bar of the Modaomen Estuary during the dry season

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2014年第7期33卷 107-115页

作者： jia Liangwen REN Jie nie Dan CHEN Benzhong LV Xiaoying Center for Coastal Ocean Science and Technology Research Sun Yat-sen University

On the basis of the measurement data pertaining to waves, current, and sediment in February 2012 in the mouth bar of the Modaomen Estuary, the Soulsby formulae with an iterative method are applied to calculating bottom shear stresses （BSS） and their effect on a sediment resuspension. Swell induced BSS have been found to be the most important part of the BSS. In this study, the correlation coefficient between a wavecurrent shear stress and SSC is 0.86, and that between current shear stresses and SSC is only 0.40. The peaks of the SSC are consistent with the height and the BSS of the swell. The swell is the main mechanism for the sediment re-suspension, and the tidal current effect on sediment re-suspension is small. The peaks of the SSC are centered on the high tidal level, and the flood tide enhances the wave shear stresses and the SSC near the bottom. The critical shear stress for sediment re-suspension at the observation station is between 0.20 and 0.30 N/m2. Tidal currents are too weak to stir up the bottom sediment into the flow, but a WCI （wave-current interaction） is strong enough to re-suspend the coarse sediment.

关键词： Modaomen Estuary wave-current bottom shear stresses sediment

The accurate localization of fluorescent nanoparticle Au-Ft in nu/nu mice kidney

在线全文

学校读者我要写书评

暂无评论

Journal of Innovative Optical Health Sciences 2014年第3期7卷 83-90页

作者： Hui Yang Cuji Sun Jun jia Guangjun nie Zhenyu Wu Department of Immunology Guang'anmen HospitalP.R.China Academy of Chinese Medical Sciences Beijing 100053P.R.China CAS Key Laboratory for Biomedical Effects of Nanomaterials&Nanosafety Nationai Center for Nanoscience and Technology Beijing 100190 P.R.China Chilong Healthcare Intermational Limited Beijing 1000%0 P.R.China

Au-Ft,as a green synthesized nanoparticle,is composed of a ferritin nanocage enclosing a pair of Au nanoclusters *** previous study has demonstrated that Au-Ft can be an excellentfluorescent probe for whole body imaging of mice with kidney specific ***,the accuratelocalization of Au-Ft in kidney is still *** the current study,we detected and assessed the cellular and subcellular localization of Au-Ft in renal cortex and medulla of nu/nu mice after tailvein injection by using Nuance optical system(CRi,Woburn,USA)and inForm intelligent image analysis soft ware based on single cell *** obtained the fluorescence intensity and cellular location of kidney-targeting Au-Ft probe in particular cell of renal glomerulus or renaltubules,which provided valuable proofs to clarify the mechanism of Au-Ft selective enrichment in kidney and the associated metabolic processes.

关键词： Au-Ft nanoparticle kidney targeting cellular localization renal cortex and medlla multispectral imaging

Dynamic frequency response characteristics of a compound regulative quasi-zero stiffness air spring system

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第7期66卷 2013-2024页

作者： shi Yan XU ShaoFeng LI ZhiLong WANG YiXuan nie YuLong SUN ZhiBo School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Jingdezhen Research Institute of Beihang University Jingdezhen 333032China School of Mechanical Engineering Inner Mongolia University of Science and TechnologyBaotou 014010China Engineering Training Center Beihang UniversityBeijing 100191China

Quasi-zero stiffness(QZS) device is widely studied for their better performance in low-frequency and micro-vibration isolation due to the high-static and low-dynamic(HSLD) stiffness *** previous QZS isolator with determined parameters is not suitable for variable isolated *** this study,a novel compound regulative quasi-zero stiffness air spring(CRQSAS)has been proposed and designed by introducing a bidirectional regulator for the horizontal air *** CRQSAS could change the quasi-zero region depending on the *** identify the parameters of the convoluted air spring(CAS) and novel rubber air spring(NRAS),the air spring testing system is *** stiffness functions of air springs are obtained by the multi-parameter fitting *** to the structure of the CRQSAS,the dynamic model of the system is analyzed and simplified by Taylor *** harmonic balance method(HBM) is applied to calculate the frequency response and absolute displacement *** experimental prototype has been set up to verify the theoretical model and *** with the single NRAS,CRQSAS performs better in low-frequency and micro-amplitude *** research proves that CRQSAS is a passive device widely applied for improving isolation precision under low-frequency vibration.

关键词： quasi-zero stiffness air springs frequency response low-frequency vibration

Single-cell transcriptomes and runx2b-/- mutants reveal the genetic signatures of intermuscular bone formation in zebrafish

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第11期9卷 97-107页

作者： Chun-Hong nie shi-Ming Wan Yu-Long Chen Ann Huysseune Ya-Ming Wu jia-jia Zhou Alexandre Wagner Silva Hilsdorf Wei-Min Wang Paul Eckhard Witten Qiang Lin Ze-Xia Gao College of Fisheries Key Lab of Freshwater Animal BreedingMinistry of Agriculture and Rural AffairsKey Lab of Agricultural Animal GeneticsBreeding and Reproduction of Ministry of EducationEngineering Research Center of Green Development for Conventional Aquatic Biological Industry in the Yangtze River Economic Belt Ministry of Education Huazhong Agricultural University Hubei Hongshan Laboratory CAS Key Laboratory of Tropical Marine Bio-Resources and Ecology South China Sea Institute of Oceanology Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of Sciences Department of Biology Ghent University Unit of Biotechnology University of Mogi das Cruzes Guangdong Laboratory for Lingnan Modern Agriculture

Intermuscular bones(IBs) are mineralized spicules, present in the myosepta of many, but not all, teleost species. IBs are often small and sharp, and they consequently limit how the fish can be processed; the IBs may cause injury or trauma if lodged in consumers’ throats or mouths, and therefore affect the appeal of the fish to many consumers. The development of IBs in teleosts is still not fully understood and the molecular basis of IB development remains to be established. Here, the characteristics of IB tissue are evaluated based on single-cell transcriptomics in wild-type zebrafish. The analysis defined 18 distinct cell *** trajectories showed that IBs are derived from tendons and that a core tendon-osteoblast cell lineage is related to IB formation. In particular, the functions of 10 candidate genes were evaluated via CRISPR-Cas9 mutants. Among those, runx2b-/-mutants completely lost IBs, while swimming performance, growth and bone mineral density were not significantly different from runx2b+/+*** single-cell RNA sequencing(sc RNA-seq) analysis in runx2b-/-and runx2b+/+zebrafish revealed the role of osteoblasts in IB formation. In addition, differentially expressed genes were enriched in the transforming growth factor β/bone morphogenetic protein(TGF-β/BMP) pathway after runx2b deletion. This study provides evidence for the crucial role of runx2b regulation in IB formation. Genetic breeding can target runx2b regulation and generate strains of commercial fish species without IBs, which can improve the safe consumption and economic value of many farmed fish species.

关键词： teleosts zebrafish intermuscular bones scRNA-seq tendon-osteoblast cell lineage runx2b genetic breeding

Drill string dynamic characteristics simulation for the ultra-deep well drilling on the south margins of Junggar Basin

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Petroleum 2023年第2期9卷 205-213页

作者： Yuan Li jianggang shi Minghu nie Chi Peng Yingjie Wang Institute of Petrol Engineering Technology of PetroChina Xinjiang Oilfield Branch KaramayChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Engineering Southwest Petroleum UniversityChengdu610500China

Improper drilling parameters may cause severe vibration of drill string which leads to reduce the rate of penetration and drilling tool premature failure accidents in the drilling process of ultra-deep *** study on dynamic characteristics of drill string plays an important role in increasing the safety of drilling tool and optimizing the drilling *** the influences of real borehole trajectory,interaction between bit and formation,contact between drill string and borehole wall,stiction of drilling fluid and other factors,a comprehensive drill string dynamic model was established to simulate the changes of wellhead hook load,torque,equivalent stress of drill string and BHA(bottomhole assembly)section acceleration and motion trajectory with time at different WOBs(weights on bit)and rotary *** safety factor and overpull margin of wellhead drill string were calculated and the strength of drilling tool in ultra-deep well was checked using the fourth strength *** analysis results show that,in the drilling process of ultra-deep well,the transverse motion amplitude of the drill string near the wellhead is relatively small and vibration of drill string mainly occurs in the lower well *** the rotary speed increases,the number of collision between lower drilling tool and borehole wall increases,wellhead transverse stress increases,change in torque is not large and change in wellhead equivalent stress is relatively *** the WOB increases,wellhead torque will increase,axial load and equivalent stress will decrease and vibration acceleration of BHA will increase *** overpull margin and safety factor will decrease with the increase of rotary speed and increase with the increase of *** safety factor of S135 drilling tool in an F190.5 mm ultra-deep well on the south margins of Junggar basin changes around *** drilling tool is safe and has relatively sufficient ability to deal with the downhole accidents if a l

关键词： Ultra-deep well Drilling tool failure Drill string dynamics Drill string strength check Drilling parameter optimization

Health risk assessment of dietary exposure to polycyclic aromatic hydrocarbons in Taiyuan, China

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2014年第2期26卷 432-439页

作者： Jing nie Jing shi Xiaoli Duan Beibei Wang Nan Huang Xiuge Zhao Chinese Research Academy of Environmental Sciences State Key Lab of Environmental Criteria and Risk Assessment Soil and Water Science College of Resources and Environmental Sciences China Agricultural University Department of Safety Engineering China Institute of Industrial Relations

Sixteen polycyclic aromatic hydrocarbons （PAHs） were determined in 24 duplicate-diet samples from people in Taiyuan during summer and winter in 2009. Dietary intake of PAHs for 2862 participants was subsequently estimated by a survey in Taiyuan. Results from these 24 samples were compared with a raw food study in Taiyuan in 2008. Three main sources of dietary PAHs are vegetables, wheat flour and fruits, the sum of which contributes 75.95% of PAHs in dietary food. Compared to the estimated value in raw food, much more B[a]Peq （benzo[a]pyrene equivalents） were detected in food samples collected in the duplicate-diet study in Taiyuan （60.75 ng/day）. The cooking process may introduce more B[a]Peq into food, and the relative contribution of 16 PAHs in the diet would be changed during the cooking procedure.

关键词： dietary exposure food health risk assessment polycyclic aromatic hydrocarbons (PAHs) benzo[a]pyrene

High Temperature Phase Transitions in Na_xCoO_2 Materials

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第8期25卷 997-1003页

作者： nie Chang-jiang YANG Huai-Xin shi You-Guo LI jian-Qi Department of Physics Xiaogan University Xiaogan 432100 China Beijing National Laboratory for Condensed Matter Physics Institute of Physics The Chinese Academy of Sciences Beijing 100080 China

Structural and thermal transitions in the materials with nominal compositions of NaxCoO2 （0.5≤x≤0.75） have been investigated from room temperature to 800 K. In-situ heating transmission electron microscopy observations revealed certain distinctive structural phase transitions commonly existing in this system. A superstructure hexagonal phase, proposed arising from partial Na ordering, appears in this system in a high temperature range. The structural model for the superstructure phase has been given. Measurements of thermogravimetry （TG） and differential thermal analysis （DTA） demonstrated that certain structural phase transitions appear around 430 K. NaxCoO2 is decomposed at a temperature higher than 600 K.

关键词： NaxCoO2 phase transition superstructure

Novel and Efficient Syntheses of Four Useful shikimate- derived Epoxy Chiral Building Blocks via Cyclic Sulfite Intermediates

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2012年第12期30卷 2759-2766页

作者： Quan Na nie Liangdeng shi Xiaoxin Zhu Ruiheng Lu Xian Department of Pharmaceutical Engineering School of Pharmacy East China University of Science and Technology Shanghai 200237 China

All of the four stereoisomers of methyl 4,5-epoxy-3-hydroxy-cyclohex-l-ene-carboxylate （la--ld） are useful chiral building blocks. Novel and efficient syntheses of these four epoxy chiral building blocks from naturally abun- dant （--）-shikimic acid （2） via cyclic sulfite intermediates are described in this article. The targeted compound （3R,4R,5S）-la was synthesized via four steps from （--）-shikimic acid in 79% overall yield. The other three targeted compounds （3S,4R,5S）-lb, （3S,4S,5R）-1c and （3R,4S,5R）-ld were synthesized via seven steps from （--）-shikimic acid in 56%, 64% and 65% overall yields, respectively.

关键词： chiron cyclic sulfite epoxide shikimic acid synthesis

Phase-Field Simulation of δ Hydride Precipitation with Interfacial Anisotropy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第11期77卷 1425-1443页

作者： Hailong nie Xincheng shi Wenkui Yang Kaile Wang Yuhong Zhao School of Materials Science and Engineering Collaborative Innovation Center of Ministry of Education and Shanxi Province for High-Performance Al/Mg Alloy MaterialsNorth University of ChinaTaiyuan030051China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing100083China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang110004China

Previous studies ofδhydride in zirconium alloys have mainly assumed an isotropic *** practice,the difference in crystal structure at the interface between the matrix phase and the precipitate phase results in an anisotropic *** the purpose of probing the real evolution ofδhydrides,this paper couples an anisotropy function in the interfacial energy and interfacial *** influence of anisotropic interfacial energy and interfacial mobility on the morphology ofδhydride precipitation was investigated using the phase-field *** results show that the isotropy hydride precipitates a slate-like morphology,and the anisotropicδhydride precipitates at the semi-coherent and non-coherent interfaces exhibited parallelogram-like and needle-like,which is consistent with the actual experimental *** with the coherent interface,the semi-coherent or non-coherent interface adjusts the lattice mismatch,resulting in lower gradient energy that is more consistent with the true interfacial ***,an important chain of relationships is proposed,in the range of I_(x)1.5I_(x)),with the increase of the anisotropic mobility I_(y) in the y-axis,the gradient energy increases(decreases),the tendency of the non-coherent(semi-coherent)relationship at the interface,and the precipitation rate of hydride decreases(increases).Furthermore,the inhomogeneous stress distribution around the hydride leads to a localized enrichment of the hydrogen concentration,producing a hydride *** study of interfacial anisotropy is informative for future studies ofδhydride precipitation orientation and properties.

关键词： Zirconium δhydride phase-field method interfacial anisotropy interfacial mobility