检索结果-南通市图书馆

Hydrodynamic Characteristics of Undular Tidal Bores in the Qiantang River Based on Field Observations

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2024年第3期38卷 505-518页

作者： zhang shu-yu PAN Cun-hong zhang Shen-yang LI Ruo-hua CHENG Wenlong XIE Dong-feng Zhejiang Tongji Vocational College of Science and Technology Hangzhou 311231China Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China

Understanding the undular tidal bores in the Qiantang River is essential for effective river management and *** breaking tidal bores have been studied extensively, reports on undular tidal bores in the Qiantang Riverremain limited. Furthermore, observed data on undular tidal bores fulfilling the requirements of short measurementtime intervals, and spring, medium, and neap tide coverage, and providing detailed data for the global vertical stratificationof flow velocity are quite limited. Based on field observations at Qige in the Qiantang estuary, we analyzedthe characteristics of undular tidal bores. The results showed that the flooding amplitude (a) of the first wave isalways larger than its ebbing amplitude (b). Moreover, the vertical distribution of the maximum flood velocity exhibitesthree shapes, influenced by the tidal range, while that of the maximum ebb velocity exhibites a single shape. Duringthe initial phase of the flood tide in the spring and medium tides, the upper water body experiences multiple oscillatingchanges along the flow direction, corresponding to the alternating process of the crest and trough of the tide levelupon the arrival of the tidal bore. The tidal range is a crucial parameter in tidal bore hydrodynamics. By establishingthe relationship between hydrodynamic parameters and tidal range, other hydrodynamic parameters, such as the tidalbore height, maximum flood depth–averaged velocity, maximum flood stratified velocity at the measurement points,and duration of the flood tide current, can be effectively predicted, thereby providing an important reference for rivermanagement and maintenance.

关键词： tidal bores Qiantang Estuary tidal bore height tidal bore velocity propagation speed

Adaptation of potato production to climate change by optimizing sowing date in the Loess Plateau of central Gansu, China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2015年第2期14卷 398-409页

作者： WANG Chun-ling SHEN shuang-he zhang shu-yu LI Qiao-zhen YAO yu-bi School of Applied Meteorology Nanjing University of Information Science and Technology Key Laboratory of Arid Climate Change and Reducing Disaster of Gansu Province Lanzhou Institute of Arid Meteorology China Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster Meteorological Bureau of Dingxi City

Potato grows in most part of China, it achieves higher yield and better quality in Gansu Province than in others. With global warming, its growth duration has been prolonged and sowing date become earlier than before. Therefore, to regulate its sowing date and growing period is of great significance for better harvest. In this study, experiments were conducted with six sowing-date treatments of potato in Dingxi, which is in the Loess Plateau of central Gansu Province in Northwest China in 2010. The growth period, morphological index and change in yield and their relationships with temperature, precipitation, and other climatic factors were investigated for each treatment. Results show that the crop with different sowing dates experienced different climate conditions, leading to distinct growth duration, plant height, and leaf area index. The growth duration was shortened due to a delay in sowing date. For each 15-day delay in sowing, the growth duration was reduced by 12 days on average. A significant linear relationship was found between numbers of days either from seeding to emergence or from flowering to harvest and mean temperature over the corresponding period. Dry matter accumulation, tuber fresh weight, and final yield were all decreased because of insufficient cumulative temperature over the shorter growing periods. Marked differences in tuber yield were discovered among the six treatments of sowing date, the potato planted on May 27 giving the highest yield. The potato planted either earlier or later would produce invariably lower yield than the treatment of May 27. Late May therefore can be taken as the optimum sowing time of potato in this region because the crop can fully utilize thermal resource. We conclude that to postpone sowing time is a good practice for potato production to adapt to climate warming in the Loess Plateau of central Gansu, China.

关键词： potato climate change optimum sowing date growth and development tuber yield

High Sensitive Long Period Fiber Grating Sensor for Detection of Nitrite

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2009年第5期25卷 624-627页

作者： QIAN Ying yu Yong-sen LI Qiu-shun WU Si-zhu ZHAO Kai-jun YANG Bai-liang zhang yu-shu State Key Laboratory on Integrated Optoelectronies College of Electronic Science and Engineering College of Chemistry Jilin University Changchun 130012 P R. China Electrical Diagnosis Division China-Japan Union Hospital Jilin University Changchun 130033 P R. China

A high sensitive long period fiber grating（LPFG） sensor for the detection of nitrite is proposed, which is realized by coating multiple poly（sodium 4-styrensulfonate）（PSS） and poly（diallyldimethylammonium） chloride （PDDA） layers on the fiber grating surface. The sensitivity of this LPFG sensor is maximum when the number of assembled layers is 70. Under this condition, a nitrite concentration of 3×10^-3 mol/L, which is lower than the National Food Additive Standard, 4.2×10^-3 mol/L, can be distinguished. The sensitivity is further increased by 30% when nitrite was determined in the sucrose solution with a concentration of 65%, which provides a new solution for the best refraction index approaching matched index of the fiber cladding. Compared with chemical methods, this nitrite detection technology offers some advantages, such as high accuracy, non toxicity, high speed, low cost, without chemical reagent, and is suitable for foodstuff security detection.

关键词： Long period fiber gratings Refractive index sensor Detection of nitrite

Effects of Simulated Heat Wave and Ozone on High Fat Diet ApoE Deficient Mice

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2018年第10期31卷 757-768页

作者： SONG Quan Quan NIN Jing Ping zhang shu yu LIANG Ting Ting ZHOU Ji FENG Shan Shan Institute of Occupational and Environmental Health School of Public Health Lanzhou University Lanzhou 730000Gansu China Key Laboratory of Meteorology and Ecological Environment of Hebei Province Hebei Provincial Meteorological Bureau Shijiazhuang 050021 Hebei China Yangtze River Delta Environmental Weather Forecast Center Shanghai 200030 China Gansu University of Traditional Chinese Medicine Lanzhou 730000 Gansu China

Objective To discuss the cardiac toxicities of a heat waves and ozone exposure on cardiovascular diseases（CVDs） and explore a possible mechanism. Methods The incidence of ozone exposure combined with heat wave was simulated in the Shanghai Meteorological and Environmental Animal Exposure System（Shanghai-METAS）. A total of 64 Apo E-/-mice, matched by weight, were randomly divided into 8 groups and exposed to heat wave conditions or ozone. The levels of creatine kinase（CK）, D-lactate dehydrogenase（D-LDH）, intercellular adhesion molecule 1（sICAM-1）, tumor necrosis factor alpha（TNF-α）, nitric oxide（NO）, endothelin-1（ET-1）, D-dimer（D2 D）, plasminogen activator inhibitor-1（PAI-1） and blood lipid in plasma and heat shock protein-60（HSP60）, hypoxia inducible factor 1 alpha（HIF-1α）, interleukin-6（IL-6）, C-reactive protein（CRP）, superoxide dismutase（SOD）, and malondialdehyde（MDA） in hearts were measured after exposure. Results The levels of all indicators, except for SOD, increased with the ozone-only exposure. However, cardiac damage was most significant when the heat wave conditions were combined with severe ozone exposure. Moreover, the levels of CK, D-LDH, NO, PAI-1, sICAM-1, and TNF-α in plasma increased significantly（P 〈 0.05）, and the contents of HSP60, HIF-1α, CRP, and MDA in hearts increased considerably（P 〈 0.05）, but the activity of SOD decreased significantly. In addition, the levels of four blood lipid items remarkably increased（except the level of HDL-C which decreased significantly） with ozone exposure. Conclusion A short-term exposure to a heat wave and ozone causes severe toxic effects on the heart. Cardiac damage was most significant under combined heat wave and severe ozone exposure simulations.

关键词： Heat wave Ozone Damaging effects Cardiovascular disease Atherosclerosis mice Mechanism

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2008年第5期24卷 635-639页

作者： SHEN Ren-sheng TENG Rui LI Xiang-ping zhang Jin XIA Dao-cheng FAN Zhao-qi yu Yong-sen zhang yu-shu DU Guo-tong State Key Laboratory of Materials Modification by Laser Ion and Electron Beams School of Physics and Optoeleetronic Technology Dalian University of Technology DaIian 116024 P. R. China State Key Laboratory on Integrated Optoelectronies College of Electronic Science and Engineering Jilin University Changchun 130012 P R. China

Metal-coated fiber Bragg grating（FBG）temperature sensors were prepared via electroless nickel（EN）plating and tin electroplating methods on the surface of normal bare *** surface morphologies of the metal-coated layers were observed under a metallographic *** effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were ***, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum *** of the metal-coated FBG（MFBG）sensor was almost two times that of normal bare FBG *** measuring temperature of the MFBG sensor could be up to 280℃,which was much better than that of conventional FBG sensor.

关键词： FBG Metal-coated layer Electroless nickel plating Electroplating Temperature sensor

Poly(ethylene glycol)-supported Piperazine——Synthesis and Application in Knoevenagel Condensation

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2010年第2期26卷 263-267页

作者： WANG Cui-e JIN Jie zhang Min yu shu-yan SHANG Yong-jia HU Jin-song College of Chemistry and Materials Science Anhui Key Laboratory of Functional Molecular SolidsAnhui Key Laboratory of Molecular Based Materials Anhui Normal University Wuhu 241000 P. R. China

A soluble, poly（ethylene glycol）-supported piperazine catalyst was prepared. This soluble catalyst efficiently catalyzes the Knoevenagel condensation of various aromatic aldehydes with diethyl malonate or ethyl acetoacetate in a homogeneous phase to afford the desired alkenes in good purity and yield with a facile work-up process. It was found that the polymer reagent could be repeatedly used at least four times without the too much loss of activity. The catalyst has shown a good activity, stability, and recycling capability.

关键词： Piperazine Polymer-supported catalyst Knoevenagel condensation

Abnormal Shift of Center Wavelength in Annealing Long-Period Gratings

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2000年第1期17卷 28-30页

作者： QIN Li WEI Zhan-Xiong WANG Qing-Ya LI Hui-Ping zhang yu-shu GAO Ding-San Department of Electronics Engineering Jilin UniversityChangchun 130023

During annealing process of long-period gratings,the center wavelengths of some inodes shift to red wavelength while those of others shift to blue compared with their original written ones,and the magnitudes of the shifts are related to the decay of the grating *** red shifts of center wavelength are more evident in lower-order inodes of the *** suggest that part of the photodissociated-H2 combines continuously with Ge-defect centers within 2 h after UV-exposure,and with which the observed abnormal shifts can be explained successfully.

关键词： center Shift annealing

Advances in Nitrogen Denitrification and N_2O Emission in Agro-ecosystem

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

Agricultural Science & Technology 2011年第2期12卷 268-273,304页

作者： zhang yu-shu DING Hong QIN Sheng-jin Institute of Soil and Fertilizer Fujian Academy of Agricultural Sciences Fuzhou 350013

Nitrification and denitrification are two key links of nitrogen flow cycle in soil.N2O and N2,generated from biochemical process of nitrogen,can cause not only the nitrogen losses and reduction of nitrogen use efficiency,but also the boosted concentration of greenhouse gases,severely endangering the ***,nitrification-denitrification has been more and more concerned from whether an agricultural view,or an environmental *** to the related literatures published at home and abroad in recent years,we overviewed the denitrification-caused N loss and N2O emission in various agro-ecosystems,and based on which we put forward countermeasures to reduce the denitrification-caused N loss and N2O emission and its research prospects in the future.

关键词： Agro-ecosystem Denitrification Nitrogen emission amount

Method for Estimating the State of Health of Lithium-ion Batteries Based on Differential Thermal Voltammetry and Sparrow Search Algorithm-Elman Neural Network

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2025年第1期122卷 203-220页

作者： yu zhang Daoyu zhang TiezhouWu School of Electrical and Electronic Engineering Hubei University of TechnologyWuhan430068China

Precisely estimating the state of health(SOH)of lithium-ion batteries is essential for battery management systems(BMS),as it plays a key role in ensuring the safe and reliable operation of battery ***,current SOH estimation methods often overlook the valuable temperature information that can effectively characterize battery aging during capacity ***,the Elman neural network,which is commonly employed for SOH estimation,exhibits several drawbacks,including slow training speed,a tendency to become trapped in local minima,and the initialization of weights and thresholds using pseudo-random numbers,leading to unstable model *** address these issues,this study addresses the challenge of precise and effective SOH detection by proposing a method for estimating the SOH of lithium-ion batteries based on differential thermal voltammetry(DTV)and an SSA-Elman neural ***,two health features(HFs)considering temperature factors and battery voltage are extracted fromthe differential thermal voltammetry curves and incremental capacity ***,the Sparrow Search Algorithm(SSA)is employed to optimize the initial weights and thresholds of the Elman neural network,forming the SSA-Elman neural network *** validate the performance,various neural networks,including the proposed SSA-Elman network,are tested using the Oxford battery aging *** experimental results demonstrate that the method developed in this study achieves superior accuracy and robustness,with a mean absolute error(MAE)of less than 0.9%and a rootmean square error(RMSE)below 1.4%.

关键词： Lithium-ion battery state of health differential thermal voltammetry Sparrow Search Algorithm