检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

Omat智能自适应控制系统

制造技术与机床 2006年第5期 120-121页

作者： Beijing Jiayuan Yirun science & technology development co., {3.. 北京嘉源易润科技发展有限公司

自适应控制技术是控制领域中的一个热点,其作用是使控制对象能够在运动过程中根据环境参数的变化,自动进行调整,保证控制对象运行在最佳状态.

关键词：自适应控制系统自适应控制技术智能控制对象控制领域环境参数运动过程最佳状态

Study on reservoir operation optimization of Ertan Hydropower Station considering GFS forecasted precipitation

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2011年第S1期54卷 76-82页

作者： PENG Yong 1,WANG GuoLi 1,TANG GuoLei 1,ZHOU HuiCheng 1,WANG YaJun 2 & JIAN DePing 2 1 Institute of Water Resources and Flood control,Dalian University of technology,Dalian 116023.china 2 Ertan Hydropower development co.,{3..,Chengdu 610021,china 1. Institute of Water Resources and Flood control Dalian University of Technology Dalian 116023 China 2. Ertan Hydropower development co. Ltd. Chengdu 610021 China

The medium-term runoff forecasting provided new information for forecast of medium and long term runoff and optimal hydroelectric power *** to the actual runoff and hydropower generating characteristics of Ertan Hydropower Station,we studied the decade runoff quantitatively and grade forecast model based on Global Forecasting System(GFS) precipitation forecast information in wet season,then used the posteriori runoff transition probability and measurable probability of runoff forecast to research the uncertain runoff description based on runoff forecast;finally on the basis of the runoff description and the grading forecast accuracy of GFS-based next 10 days'total forecast precipitation,we studied the uncertain optimal operating model of Ertan Hydropower Station considering runoff *** results showed that the runoff forecast considering GFS forecast precipitation and uncertainty has significantly improved the existing runoff description and operating optimization model,and obviously raised the hydropower generation efficiency of Ertan Reservoir.

关键词： global forecasting system runoff forecasting runoff description uncertainty optimal operation

Preparation and properties of ultra-fine TiCN matrix cermets by vacuum microwave sintering

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2010年第5期29卷 528-532页

作者： ZHANG Hou'an YAN Dike TANG Siwen Institute of material Preparation and Applied technology Xiamen University of Technology Xiamen 361024 China college of Electromechanical Engineering Hunan University of Science and Technology Xiangtan 411201 China

Ultra-fine titanium carbonitride （TiCN） matrix materials with a grain size less than 1μm were successfully prepared by vacuum microwave sintering. The milling process for raw TiCN particles and the microstructure and properties of cermets produced with a composition of 15wt.%WC-17wt.%（co＋Ni）-9wt.%Mo2C-59wt.%***0.3.and sintered by vacuum microwave were analyzed by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that a ball-to-powder mass ratio of 8：1 and a milling time of 50 h provided appropriate conditions for the production of ultra-fine TiCN solid solution powders. The use of vacuum microwave sintering produced cermets with much finer grain and black core structures and higher relative density and hardness than those produced by vacuum sintering technology.

关键词： cutting tools titanium carbonitride grain size microwave sintering milling hardness

Photoluminescence and cathodoluminescence properties of a novel CaLaGa_3._7:Dy^(3.) phosphor

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 2012年第7期57卷 827-831页

作者： ZHAO WenYu1,2, AN ShengLi1, FAN Bin1, LI SongBo1 & DAI YaTang3.1 School of Metallurgical and Ecological Engineering, University of science and technology Beijing, Beijing 100083. china 2 School of Chemistry and Chemical Engineering, Inner Mongolia University of science and technology, Baotou 014010, china 3.School of materials science and Engineering, Southwest University of science and technology, Mianyang 621000, china School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Chemistry and Chemical Engineering Inner Mongolia University of Science and Technology

A single host white emitting phosphor, CaLaGa3.7:Dy3., was synthesized by chemical co-precipitation. Field emission scanning electron microscopy, X-ray diffraction, laser particle size analysis, and photoluminescence and cathodoluminescence spectra were used to investigate the structural and optical properties of the phosphor. The phosphor particles were composed of microspheres with a slight tendency to agglomerate, and an average diameter was of about 1.0 μm. The Dy3. ions acted as luminescent centers, and substituted La3. ions in the single crystal lattice of CaLaGa3.7 where they were located in Cs sites. Under excitation with ultraviolet light and a low voltage electron beam, the CaLaGa3.7:Dy3. phosphor exhibited the characteristic emission of Dy3. (4F9/2-6H15/2 and 4F9/2-6H13.2 transitions) with intense yellow emission at about 573.nm. The chromaticity coordinates for the phosphor were in the white region. The relevant luminescence mechanisms of the phosphor are investigated. This phosphor may be applied in both field emission displays and white light-emitting diodes.

关键词：光致发光阴极射线荧光粉镝离子场发射扫描电子显微镜白色发光二极管特性 X射线衍射仪

Physical and Chemical Transformation of Hydroxyapatite Nanoparticles in Aqueous Sol after Preparation and in vitro

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan University of technology(materials {3.) 2005年第B12期20卷 283-286页

作者： I W Bauer 李世普 Biomedical materials and Engineering Research Center Wuhan University of TechnologyWuhan 430070China

The co-precipitation method followed by ultrasound and heat treatment is a common way to prepare below 100 nm sized hydroxyapathe nanoparticles for biomedical studies and applications. The size and pH value of the obtained calcium phosphate nanoparticles in aqueous sol have a strong impact on the interactions with cells and tissue. The physical and chemical properties of material samples for in vitro and in vivo studies are often assumed to remain constant from the time after fabrication to the actual use. Only little attention is paid to eventual changes of the material over time or due to the different in vitro conditions. In this study, the physical and chemical transformation of calcium phosphate nanoparticles after preparation and in vitro was investigated. As the result showed, dispersed nano sized amorphons calcium phosphate precipitation as well as crystallized hydroxyapathe nanoparticles continue to crystallize even when kept at 4℃ leading to declining pH values and particle sizes. Due to the pH buffer in the medium the pH value of the cell culture remained stable after adding 20% nanoparticle sol in vitro. However, hydroxyapathe nanoparticles immediately became unstable in the presents of cell culture medium. The resulting loose agglomerations showed a size of above 500 nm.

关键词： Nanoparticles hydroxyapatite crystallization pH value particle size in vitro

Aberrant histone H4 acetylation in dead somatic cell-cloned calves

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2008年第7期18卷 813-818页

作者： Lei Zhang a,b,*, Shaohua Wang a, Qiang Li a, Xiangdong Ding c, Yunping Dai a, Ning Li a,* a State Key Laboratory for Agrobiotechnology, china Agricultural University, Beijing 100094, china b Beijing Gene & Protein Biotechnology co. ltd, Beijing 100094, china c college of Animal science and technology, china Agricultural University, Beijing 100094, china State Key Laboratory for Agrobiotechnology China Agricultural University Beijing 100094 China Beijing Gene & Protein Biotechnology co. ltd Beijing 100094 China college of Animal science and technology China Agricultural University Beijing 100094 China

In somatic cell-cloned animals, inefficient epigenetic reprogramming can result in an inappropriate gene expression and histone H4 acetylation is one of the key epigenetic modifications regulating gene expression. In this study, we investigated the levels of histone H4 acetylation of 11 development-related genes and expression levels of 19 genes in lungs of three normal control calves and nine aber- rant somatic cell-cloned calves. The results showed that nine studied genes had decreased acetylation levels in aberrant clones (p 0.05). Whereas 13.genes had significantly decreased expression (p controls and clones (p > 0.05), and only one gene had higher expression level in clones (p controls, and the level of histone H4 acetylation was even more lowered in aberrant clones than those in controls. It was suggested that the lower levels of histone H4 acetylation in aberrant clones caused by the previous memory of cell differentiation might not support enough chromatin reprogramming, thus affecting appropriate gene expressions, and growth and development of the cloned calves. To our knowledge, this is the first study on how histone H4 acetylation affects gene expression in organs of somatic cell-cloned calves.

关键词： Somatic cell-cloned calves Histone H4 acetylation Gene expression Lungs

Reduction Behavior of Sinter Based on Top Gas Recycling-Oxygen Blast Furnace

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第9期19卷 13-19页

作者： LAN Rong-zong 1 , 2 , WANG Jing-song 1 , HAN Yi-hua 1 , SHE Xue-feng 1 , WANG Lin-tao 1 , XUE Qing-guo 1 ( 1.State Key Laboratory of Advanced Metallurgy , University of science and technology Beijing , Beijing 100083., china 2.{3. Railway materials Xiamen Steel co ltd , Xiamen 3.1008 , Fujian , china ) [a] State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China [b] china Railway materials Xiamen Steel co ltd Xiamen 361008 Fujian China

In order to explore the behavior laws of sinter reduction in TGR-OBF ( top gas recycling-oxygen blast furnace ), reduction experiments of sinter have been conducted by thermal balance mass loss method with different atmospheres , temperatures and volume *** changes of RI ( reduction degree of Fe 2 O 3.), RI′ ( reduction rate of Fe 2 O 3.) and r ( reduction degree of FeO ) have been *** results show that the reduction of sinter was significantly improved under TGR-OBF atmosphere , and the RIand r were measured up to 98.2%and 97.8%at 900℃ *** increasing of the reduction temperature , the reduction of sinter speeded up greatly , and the reduction time-duration shortened from 117min at 900 ℃ to 63.in at 1 100 ℃.Moreover , the reduction of sinter enhanced with increasing of the reductive gas *** the flow increased from 10to 15L / min , the initial reduction rate of sinter increased from 2.47% / min to 3.73. / *** increasing H2and co contents in the reductive atmosphere , the reduction of sinter was *** , H 2 influenced more evidently than co to the reduction of sinter , especially in the later stage of the reduction process , for instance , the reduction of wustite will be improved enormously when increasing the H2content in the reductive atmosphere.

关键词： oxygen blast furnace sinter reduction

TGF-beta 1 Gene-Activated Matrices Regulated the Osteogenic Differentiation of BMSCs

在线全文

学校读者我要写书评

暂无评论

Journal of wuhan University of technology(materials {3.) 2007年第3期22卷 431-435页

作者：潘海涛郑启新 Department of Orthopedics Union HospitalTongji Medical CollegeHuazhong University of Science and Technology

Poly （lactic acid/glycolic acid/asparagic acid-co-polyethylene glycol）（PLGA-[ASP-PEG]） scaffold materials were linked with a novel nonviral vector （K）16GRGDSPC through cross linker Sulfo- LC-SPDP to construct a new type of nonviral gene transfer system. Eukaryotic expressing vector containing transforming growth factor beta 1 （pcDNA3.TGFβ1） was encapsulated by the system. Bone marrow stromal cells （BMSCs） obtained from rabbit were cultured on PLGA-[ASP-PEG] modified by （K）16GRGDSPC and TGF-β1 gene and PLGA-[ASP-PEG] modified by （K）16GRGDSPC and empty vector pcDNA3.as control. The expressions of osteogenic makers of the BMSCs cultured on the TGF-β1 gene-activated scaffold materials were found significantly higher than those of the control group （P〈0.05）. A brand-new way was provided for regulating seed cells to directionally differentiate into osteoblasts for bone defect restoration in bone tissue engineering.

关键词： RGD-containing peptide biomimetic matrix scaffold material osteogenic differentiation bone tissue engineering

THE EFFECTS OF SPUTTERING POWER ON STRUCTURE AND ELECTRICAL PROPERTIES OF Cu FILMS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 215-220页

作者： F.P. Wang. P. Wu, L.Q. Pan, Y. Tian and H. Qiu Department of Physics, School of Applied sciences, University of science and technology Beijing, Beijing 100083.{3. Beijing Keda-Tianyu Microelectronic material technology development co. ltd., Beijing 100 Department of Physics School of Applied Sciences University of Science and Technology Beijing

Cu films with thickness of about 500nm were deposited on glass substrateswithout heating by DC magnetron sputtering in pure Ar gas of 1.0Pa. The sputtering powers weremaintained at 3.0V X 0.27A, 43.V X 0.70A and 450V X l.04A, and the corresponding deposition rates ofCu film reached 3.nm/min, l04nm/min and 167nm/min. X-ray diffraction, scanning electron microscopyand atomic force microscopy were used to observe the structural characteristics of the films. Theresistance of the films was measured using four-point probe technique. The amount of larger grainsincreases and the resistivity of the films decreases evidently with an increase in sputtering *** is considered that the increase in deposition rate with sputtering power mainly weakens theinfluence of residual gas atoms on the growing film, and increases substrate and gas temperatures,resulting in the increase in grain size and the decrease in resistivity of the Cu film.

关键词： Cu film DC magnetron sputtering sputtering power structure resistivity