检索结果-南通市图书馆

Nonlinear interactions between gravity waves and background winds

Progress in Natural Science:Materials International 2007年第6期17卷 639-644页

作者： liu Xiao1,2.and Xu Jiyao1(1. State Key Laboratory for Space Weather, center for Space Science and {2. Research, Chinese Academy of Sciences, Beijing 100080,{2. 2. Graduate university of Chinese Academy of Sciences, Beijing 100039,{2.) State Key Laboratory for Space Weather Chinese Academy of Sciences Beijing 100080 China center for Space Science and applied Research Chinese Academy of Sciences Beijing 100080 China Graduate university Chinese Academy of Sciences Beijing 100039 China

Using the nonlinear propagating gravity waves (GW) model in the two-dimensional compressible atmosphere and the linear GW theory, the process of GW propagation in different background winds, e.g. the direction of the background wind is opposite to (dead wind) or the same as (tail wind) the direction of the horizontal phase velocity of GW, is studied. The results show that the dead wind prolongs the vertical wavelength and accelerates GW propagation. Therefore, GW propagates up to a higher height becomes instable in a short time and eventually induces an inverse jet flow. Then, the vertical wavelength is becoming short due to the nonlinear interactions between GW and the inverse jet flow. The vertical wavelength and group velocity decrease after GW propagates into the tail wind. The initial instable time is delayed. Although most of GW is trapped in the instable region, some of GW propagates above the instable region. Compared with GW propagation in the tail wind, the nonlinear interactions between GW and the dead wind are also strong. In contrast, the linear GW theory predicts that GW can propagate freely in the dead wind. The vertical wavelength simulated by the nonlinear numerical model is different from that predicted by the linear theory greatly after GW propagates into the dead wind.

关键词： gravity waves background winds vertical group velocity vertical wavelength nonlinear interactions.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Quantitative understanding of phase segregation behaviors by precisely building discrete oligo-ester-b-oligo-olefin block copolymers

引用

Science china Chemistry 2024年第3期67卷 1008-1016页

作者： Yuxin liu Rui Tan Haibing Wu Xue-hui Dong Zhengbiao Zhang College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China State Key Laboratory of Radiation Medicine and Protection Soochow UniversitySuzhou 215123China South china Advanced Institute for Soft Matter Science and Technology School of Molecular Science and EngineeringSouth China University of TechnologyGuangzhou 510640China

Block copolymers(BCPs) with high Flory-Huggins parameter(χ) and balanced surface energy have aroused tremendous interest for ultra-small nanopatterns ***,high χ and balanced surface energy are generally *** fine tune of chain structure might be a useful way to achieve high χ and balanced surface *** realize this,the block copolymer with exactly uniform chain structure,i.e.,defined molecular structure,is highly desirable for accurately evaluating the phase ***,two kinds of discrete oligo ester-b-oligo olefin block copolymers with different chemical structures(oligo lactic acid-boligo olefin BCP,oLA_(n)-b-C_(m);oligo phenyl lactic acid-b-oligo olefin BCP,oPL_(n)-b-C_(m)) were modularly synthesized through iterative growth *** effect of chain structure on segregation strength and surface properties was quantitatively investigated using the discrete BCPs as precise *** the one hand,introducing rigid and nonpolar phenyl groups into oligo ester block has a negligible effect on the chemical incompatibility,as confirmed by the identical high χ values of oLA_(n)-b-C_(m) and oPL_(n)-b-C_(m)(χ_(oLA/C)=0.2. and χ_(oPL/C)=0.19).On the other hand,the incorporation of nonpolar phenyl groups creates balanced surface energy,that is,the high χ and balanced surface energy were simultaneously achieved by oPL_(n)-b-C_(m).Therefore,sub-10 nm perpendicular nanopatterns can be easily produced upon brief thermal treatment,demonstrating its potential application in semiconductor manufacturing with ultra-small feature *** discrete BCP can serve as a quantitative and exquisite model to study the critical contribution of chain structures on phase separation behavior,providing insightful understanding to facilitate the potential application in the chip process.

关键词： discrete polymer iterative growth self-assembly highχ balanced surface

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Diamond synthesis from a system of chromium-carbide andNi_(70)Mn_(2.)Co_5 alloy

引用

Chinese Science Bulletin 1998年第24期43卷 2063-2066页

作者： LI Liangbin 1, JIANG Jinchun 1, HONG Shiming 1, ZHONG Yumao 2.and ZHANG Xinyuan 2.1. Institute of applied Physics, Sichuan Union university, Chengdu 610065,{2. 2. center for Analysis and Test, Sichuan Union university, Chengdu 610065,{2. Institute of applied Physics Sichuan Union University Chengdu China center for Analysis and Test Sichuan Union University Chengdu China

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2.powder and Ni 70Mn 2.Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 2., 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2.decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.

关键词： chromium_carbide high pressure synthesis diamond.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hierarchical linear regression models for conditional quantiles

引用

Science china mathematics 2006年第12期49卷 1800-1815页

作者： TIAN Maozai & CHEN Gemai School of Statistics, Renmin university of china, Beijing 100872. china and center for applied Statistics, Renmin university of china, Beijing 100872. china Department of mathematics and Statistics, university of Calgary, Canada School of Statistics Renmin University of China Beijing China center for applied Statistics Renmin University of China Beijing China Department of mathematics and Statistics University of Calgary Canada

The quantile regression has several useful features and therefore is gradually developing into a comprehensive approach to the statistical analysis of linear and nonlinear response models,but it cannot deal effectively with the data with a hierarchical *** practice,the existence of such data hierarchies is neither accidental nor ignorable,it is a common *** ignore this hierarchical data structure risks overlooking the importance of group effects,and may also render many of the traditional statistical analysis techniques used for studying data relationships *** the other hand,the hierarchical models take a hierarchical data structure into account and have also many applications in statistics,ranging from overdispersion to constructing min-max ***,the hierarchical models are virtually the mean regression,therefore,they cannot be used to characterize the entire conditional distribution of a dependent variable given high-dimensional ***,the estimated coefficient vector (marginal effects)is sensitive to an outlier observation on the dependent *** this article,a new approach,which is based on the Gauss-Seidel iteration and taking a full advantage of the quantile regression and hierarchical models,is *** the theoretical front,we also consider the asymptotic properties of the new method,obtaining the simple conditions for an n1/2.convergence and an asymptotic *** also illustrate the use of the technique with the real educational data which is hierarchical and how the results can be explained.

关键词： hierarchical quantile regression models,EQ algorithm,fixed effects,random effects,regression quantile.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Gene Expression of Ornithine Decarboxylase in Lung Cancers and Its Clinical Significance

引用

Acta Biochimica et Biophysica Sinica 2006年第9期38卷 639-645页

作者： hui TIAN~1* Qing HUANG~1 Lm LI~1 Xian-Xi liu~2.Yan ZHANG~2. 1 Department of Thoracic Surgery,Shandong {2. Qi Lu Hospital,Jinan 2.0012.china 2.Department of Medicine,Medical Molecular Biology Experimental {2.,Shandong {2.,Jinan 2.0012.china Department of Thoracic Surgery Shandong University Qi Lu HospitalJinan 250012 China Department of Medicine Medical Molecular Biology Experimental Center Shandong UniversityJinan 250012 China

Lung cancer is one of the most lethal cancers in china because of its high incidence and *** decarboxylase （ODC）,an important enzyme in polyamine biosynthesis,is increased incancer *** chemotherapeutic agents aimed at reducing ODC expression show inhibitory effects oncancer cell growth,so ODC can be useful in gene diagnosis and gene therapy of *** this study,weexamined the effect of antisense ODC on lung cancer cells.A-549 cells were infected with rAd-ODC/Ex3as,a recombinant adenovirus containing the cytomegalovirus promoter,green fluorescent protein gene and 12.bp antisense *** cell cycle was evaluated by flow cytometry.A nude mouse xenograft model wasused in the tumorigenicity *** transcription-polymerase chain reaction,Western blot and immuno-histochernistry were used to study the expressions of ODC on lung *** was found that the growth ofcells infected with rAd-ODC/Ex3as was substantially inhibited and cells were arrested at *** with rAd-ODC/Ex3as can suppress tumor formation in a nude mouse xenograft *** of ODC mRNA and ODC protein levels in lung cancer tissues was significantly higher than thatin normal tissues （P<0.05）,which correlated significantly with the stage of lung cancer （P<0.05）.This studysuggested that rAd-ODC/Ex3as has antitumor activity in human lung cancer *** ODC gene might playan important role in lung cancer and the overexpression of ODC might be related to the occurrence anddevelopment of lung cancer.

关键词： polyamine biosynthesis lung neoplasm ornithine decarboxylase A-549 cell line

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The key mediator of diabetic kidney disease:Potassium channel dysfunction

引用

Genes & Diseases 2024年第4期11卷 188-200页

作者： Jia Guo Chaojie Zhang hui Zhao Yufan Yan Zhangsuo liu Nephrology Research center The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province ZhengzhouHenan 450052China Research center for Kidney Disease ZhengzhouHenan 450052China

Diabetic kidney disease is a leading cause of end-stage renal disease,making it a global public health *** molecular mechanisms underlying diabetic kidney disease have not been elucidated due to its complex ***,exploring these mechanisms from new perspectives is the current focus of research concerning diabetic kidney *** channels are important proteins that maintain the physiological functions of cells and *** ion channels,potassium channels stand out,because they are the most common and important channels on eukaryotic cell surfaces and function as the basis for cell *** potassium channel abnormalities have been found to be closely related to diabetic kid-ney disease progression and genetic susceptibility,such as K_(ATP),K_(ca),K_(ir),and K_(v).In this review,we summarized the roles of different types of potassium channels in the occurrence and devel-opment of diabetic kidney disease to discuss whether the development of DKD is due to potas-sium channel dysfunction and present new ideas for the treatment of DKD.

关键词： Channel dysfunction Diabetic kidney disease End-stage renal disease lon channel Potassium

来源：

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

Adenovirus-mediated Expression of both Antisense Ornithine Decarboxylase and S-adenosylmethionine Decarboxylase Inhibits Lung Cancer Cell Growth

引用

Acta Biochimica et Biophysica Sinica 2007年第6期39卷 423-430页

作者： hui TIAN~(1*), Xianxi liu~2. Bing ZHANG~2. Qifeng SUN~1, and Dongfeng SUN~1 1 Department of Thoracic Surgery, Qi Lu Hospital, Shandong {2. Jinan 2.0012. china 2.Department of Medicine, Medical Molecular Biology Experimental {2., Shandong {2. Jinan 2.0012.3} Department of Thoracic Surgery Qi Lu Hospital Shandong UniversityJinan 250012 China Department of Medicine Medical Molecular Biology Experimental Center Shandong UniversityJinan 250012 China

Polyamine biosynthesis is controlled primarily by ornithine decarboxylase （ODC） and Sadenosylmethionine decarboxylase （AdoMetDC）. Antisense sequences of ODC and AdoMetDC genes were cloned into an adenoviral vector （named Ad-ODC-AdoMetDCas）. To evaluate the effects of recombinant adenovirus Ad-ODC-AdoMetDCas that can simultaneously express both antisense ODC and AdoMetDC, the human lung cancer cell line A-549 was infected with Ad-ODC-AdoMetDCas or the control vector. Viable cell counting, determination of polyamine concentrations, cell cycle analysis, and Matrigel invasion assays were carried out to assess the properties of tumor growth and invasiveness. Our study showed that adenovirus-mediated antisense ODC and AdoMetDC expression inhibits tumor cell growth through blocking the polyamine synthesis pathway. Tumor cells were arrested at the G1phase after gene transfer and the invasiveness was reduced. It suggested that the recombinant adenovirus Ad-ODC-AdoMetDCas might be a new anticancer reagent in the treatment of lung cancers.

关键词： ornithine decarboxylase S-adenosylmethionine decarboxylase polyamine lung cancer genetherapy

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Large-eddy simulations and vortex structures of turbulent jets in crossflow

引用

Science china(Physics,Mechanics & Astronomy) 2007年第1期50卷 118-132页

作者： GUAN hui1,2.& WU ChuiJie2.1 School of Mechanical and Power Engineering,East{2. university of Science and Technology,Shanghai 2.02.7,{2. 2.Research center for Fluid Dynamics,PLA university of Science and Technology,Nanjing 2.1101,{2. School of Mechanical and Power Engineering East China University of Science and Technology Shanghai China Research center for Fluid Dynamics PLA University of Science and Technology Nanjing China

Using the method of large-eddy simulation, the 3-dimensional turbulent jets in crossflow with stream-wise and transverse arrangements of nozzle are simulated, emphasizing on the dynamical process of generation and evolution of vortex structures in these flows. The results show that the basic vortex structures in literatures, such as the counter-rotating vortex pair, leading-edge vortices, lee-side vortices, hanging vortices, kidney vortices and anti-kidney vortices, are not independent physical substances, but local structures of the basic vortex structure of turbulent jets in crossflow-the 3-D stretching vortex rings originating from the orifice of the nozzle, which is discovered in this study. Therefore, the most important large-scale structures of turbulent jets in crossflow are unified to the 3-D vortex rings which stretch and twist in stream-wise and swing in transverse directions. We also found that the shedding frequencies of vortex rings are much lower than the one corresponding to the appearance of leading-edge and lee-side vortices in the turbulent jets.

关键词： turbulent jet in crossflow coherent structure large-eddy simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On-demand engineerable visible spectrum by fine control of electrochemical reactions

引用

National Science Review 2024年第3期11卷 239-249页

作者： Qirong liu Lei liu Yongping Zheng Min Li Baofu Ding Xungang Diao {2.-Ming Cheng Yongbing Tang Advanced Energy Storage Technology Research center Shenzhen Institute of Advanced TechnologyChinese Academy of Sciences Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced Technology Chinese Academy of Sciences School of Energy and Power Engineering North University of China School of Resource Environment and Safety EngineeringHunan University of Science and Technology School of Energy and Power Engineering Beihang University Shenzhen Key Laboratory of Energy Materials for Carbon Neutrality Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences

Tunability of optical performance is one of the key technologies for adaptive optoelectronic applications,such as camouflage clothing, displays, and infrared shielding. High-precision spectral tunability is of great importance for some special applications with on-demand adaptability but remains challenging. Here we demonstrate a galvanostatic control strategy to achieve this goal, relying on the finding of the quantitative correlation between optical properties and electrochemical reactions within materials. An electrochromic electro-optical efficiency index is established to optically fingerprint and precisely identify electrochemical redox reactions in the electrochromic device. Consequently, the charge-transfer process during galvanostatic electrochemical reaction can be quantitatively regulated, permitting precise control over the final optical performance and on-demand adaptability of electrochromic devices as evidenced by an ultralow deviation of <3.0%. These findings not only provide opportunities for future adaptive optoelectronic applications with strict demand on precise spectral tunability but also will promote in situ quantitative research in a wide range of spectroelectrochemistry, electrochemical energy storage, electrocatalysis, and material chemistry.

关键词： electrochromics fine control spectral tunability high precision galvanostatic control

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Super-high bed sintering for iron ores:problems ascertainment

引用

Journal of Iron and Steel Research International 2024年第5期31卷 1063-1070页

作者： Liang-ping Xu hui-bo liu Yu-chao Zhao Qiang Zhong Zhong-lin Dong Guang-hui Li Tao Jiang School of Minerals Processing and Bioengineering Central South UniversityChangsha410083HunanChina

Super-high bed sintering process is an important development direction of iron ore sintering for its lower emission and higher ***,there is a lack of deep understanding of the uneven quality of super-high bed sintering products,and the deterioration of reduction disintegration performance,the thickening of hearth layer and the reduction in energy-saving effect are perplexing enterprises and *** ascertain the problems of super-high bed sintering,ten sintering machines with the areas of 2.5,2.0,360,550 and 660 m^(2.and bed depth above 900 mm were sampled and *** results showed that problems were mainly shown in the unevenness of chemical composition,macrostructure,mechanical strength and metallurgical *** chemical composition exhibits severe segregation in both horizontal and vertical directions,with basicity segregation reaching as high as *** uneven macrostructure of sinter is reflected in a 10%difference in porosity and mechanical strength increase in 16%–19%along the vertical *** reducibility and reduction disintegration performance gradually deteriorate along the bed depth,with a difference of 10.5%in reducibility and 7.3%in RDI−0.5 mm(reduction disintegration index of sinter with size smaller than 0.5 mm).

关键词： Super-high bed sintering Uneven sinter performance Segregation Agglomeration Iron ore

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：