光学双稳态     

潘炜 《青海师专学报》1996,(4):89-91

文中就非线性光学效应－－光学双稳态（Ｏｐｔｉｃａｌ ｂｉｓｔａｂｌｅ）在半经典理认范畴内，分别对吸收型和色散型双稳态物理机理作了描述。  相似文献   

Large eddy simulation of a particle-laden turbulent plane jet     

金晗辉  罗坤  樊建人  岑可法 《浙江大学学报(A卷英文版)》2003,4(2):175-180

Gas-solid two-phase turbulent plane jet is applied to many natural situations and in engineering systems. To predict the particle dispersion in the gas jet is of great importance in industrial applications and in the designing of engineering systems. A large eddy simulation of the two-phase plane jet was conducted to investigate the particle dispersion patterns. The particles with Stokes numbers equal to 0.0028, 0.3, 2.5, 28 (corresponding to particle diameter 1 μm, 10μm, 30μm, 100μm, respectively) inRe=11 300 gas flow were studied. The simulation results of gas phase motion agreed well with previous experimental results. And the simulation results of the solid particles motion showed that particles with different Stokes number have different spatial dispersion; and that particles with intermediate Stokes number have the largest dispersion ratio. Project (No. G19990222) supported by the Special Funds for Major State Basic Research of China  相似文献   

环境响应性核-壳结构微凝胶的受限溶胀     

李鑫 《嘉应学院学报》2005,23(6):21-26

以二步水溶液分散聚合法制备了具有温度及pH值双重响应性能的核-壳单分散纳米微凝胶,对微凝胶的形态、结构及粒径分布进行了表征,并采用动态光散射对其溶胀性能进行了研究,发现高度溶胀的P4VP壳层会对核的充分溶胀带来一定限制,并使其溶胀率下降.  相似文献   

侧链聚醚阻垢剂阻垢分散性能及机理的研究     

孙绪兵  梁兵 《内江师范学院学报》2012,27(8):32-35

研究了共聚物P（MPEGMA／AA）中单体聚乙二醇单甲醚甲基丙烯酸酯（MPEGMA,分子量550）、丙烯酸（AA）摩尔配比对阻垢分散性能的影响,并用X衍射（XRD）和电子扫描电镜（SEM）观察了碳酸钙垢晶型变化．结果表明,当共聚物中MPEGMA摩尔含量为1％～5％,共聚物具有较好的阻垢分散性能;ρCa^2＋为625mg／L,ρhco3^-为600mg／L,阻垢剂用量20mg／L时,阻碳酸钙率达70％以上;阻垢剂用量为5mg／L,阻磷酸钙率达80％以上,分散氧化铁上层清液最小透光率为62％．阻垢剂的侧链聚醚对碳酸钙垢具有晶格扭曲和分散作用．  相似文献   

一维单原子链的热容量推导     

袁松  唐敬友  任学藻  刘莉  卢喜瑞 《宜宾学院学报》2012,12(12)

在固体的热容量理论中,德拜模型是一种很好的近似,但对于固体中的晶体而言,其热容量的推导可采用更为精确的方法,而不用引入更多的假设,即只考虑原子间的简谐作用,引入声子的概念,再利用色散关系和玻色-爱因斯坦统计,便可得出热容量.一维单原子链是最简单的情形,利用该方法得到的结论为:在温度T→∞时,其热容量CV=R;在T→0时,CV∝T与以前理论中严格成立的部分相一致.  相似文献   

柱形分子N₆₆的稳定因素     

周宏伟  高晓玲 《四川教育学院学报》2013,29(3):102-109

最近的理论研究表明,氮笼分子内含有多个五元环和三元环、具有柱形结构和较多数量的层是分子稳定的因素。文章对纯氮氮笼N66(具有D3h对称性)的分子结构和能量在B3LYP/cc-pVDZ计算水平下进行探究。为了更全面地理解N66分子的结构,我们进行了NBO和AIM分析,结果表明,分子内的色散力是较大氮笼分子N66稳定性的一个重决定性因素。  相似文献   

制备条件对阴离子水性聚氨酯性能的影响     

杨磊  沈高扬  傅丽君 《莆田学院学报》2010,17(2):74-77

以二羟甲基丙酸引入亲水成分,通过预聚体分散法合成了阴离子水性聚氨酯(WPU)。对丙酮用量、加入方式,加水及加料方式,甲苯二异氰酸酯(TDI)中-NCO与聚丙二醇(PPG)中-OH摩尔量之比(R),DMPA含量及加入方式等因素对WPU制备性能的影响进行探讨。结果表明:多次加丙酮至30mL,可以缩短反应时间至5h,制备成功率达100%,且乳液性能优良;二步法实验稳定性好;在30s内分两次缓慢加水最佳;R、DMPA的量及加入方式对乳液性能有影响。  相似文献   

Cultural and Sport Economics: Conceptual Twins?   总被引：1，自引：0，他引：1  

Bruce A. Seaman 《Journal of Cultural Economics》2003,27(2):81-126

Is there a role for sports economics in arts research? Despite references to similarities between the arts and sports (especially community impacts, demand interdependencies, and the presence of superstars), the two burgeoning literatures operate in near isolation from one another. This parochialism is not justified by legitimate distinctions; arts labor analysis, in particular, could benefit from sports research. This paper demonstrates this proposition with a focus on: team production functions and income dispersion; unions and rent distribution; managerial and director productivity; earnings functions and changing talent distributions related to competing superstar theories; and career development, screening and human capital theory.  相似文献   

Can the development of a patient’s condition be predicted through intelligent inquiry under the e-health business mode? Sequential feature map-based disease risk prediction upon features selected from cognitive diagnosis big data     

《International Journal of Information Management》2020

The data-driven mode has promoted the researches of preventive medicine. In prediction of disease risks, physicians’ clinical cognitive diagnosis data can be used for early prevention of diseases and, therefore, to reduce medical cost, to improve accessibility of medical services and to lower medical risk. However, researches involved no physicians’ cognition of patients’ conditions in intelligent inquiry under e-health business mode, offered no diagnosis big data, neglected the values of the fused text information generated by joint activities of online and offline medical data, and failed to thoroughly analyze the phenomenon of redundancy-complementarity dispersion caused by high-order information shortage from the online inquiry data-driven perspective. Besides, the risk prediction simply based on offline clinical cognitive diagnosis data undoubtedly reduces prediction precision. Importantly, relevant researches rarely considered temporal relationships of different medical events, did not conduct detailed analysis on practical problems of pattern explosion, did not offer a thought of intelligent portrayal map, and did not conduct relevant risk prediction based on the sub-maps obtained from the map. In consequence, the paper presents a disease risk prediction method with the model for redundancy-complementarity dispersion-based feature selection from physicians’ online cognitive diagnosis big data to realize features selection from the cognitive diagnosis big data of online intelligent inquiry; the obtained features were ranked intelligently for subsequent high-dimensional information shortage compensation; the compensated key feature information of the cognitive diagnosis big data was fused with offline electronic medical record (EMR) to form the virtual electronic medical record (VEMR). The formed VEMR was combined with the method of the sequential feature map for modelling, and a sequential feature map-based model for disease risk prediction was presented to obtain online users’ medical conditions. A neighborhood-based collaborative prediction model was presented for prediction of an online intelligent medical inquiry user’s possible diseases in the future and to intelligently rank the risk probabilities of the diseases. In the experiments, the online intelligent medical inquiry users’ VEMRs were used as the foundation of the simulation experiments to predict disease risks in chronic obstructive pulmonary disease (OCPD) population and rheumatic heart disease (RHD) population. The experiments demonstrated that the presented method showed relatively good metric performances in the VEMR and improved disease risk prediction.  相似文献   

Application of iterated Laplace transformation to tracer transients in heterogeneous porous media     

Ibrahim Kocabas 《Journal of The Franklin Institute》2011,348(7):1339-1362

The Laplace transformation technique has been widely applied to modeling of tracer transport in oil and geothermal reservoirs, and in groundwater aquifers. However, mathematical models of many flow and transport problems could only be obtained as Laplace space solutions, and hence, their computations had to involve a numerical inversion technique.In this work, we employ the iterated Laplace transformation technique to develop novel closed form solutions to the tracer transport models in heterogeneous media. Two types of configurations have been considered: tracer transport in single fracture located in low-permeability matrix and tracer transport in a double porosity medium consisting of flowing and dead-end pore systems. In addition, both linear and radial flow geometries have been considered for both configurations. Applications of iterated Laplace transform technique to these four types of models are presented as fundamental examples and their numerical results were used as benchmarking for the numerical inversion results from Stehfest and Dubner and Abate algorithms.As the technique is quite versatile, we expect that the method should gain widespread acceptance to develop solutions to a wide range of problems in flow and transport in porous media and improve the application of nonlinear regression technique to these solutions.This work has achieved four important objectives: first, two novel Laplace transform relations that are useful in tracer studies are presented. Second, the present work serves to verify/invalidate the results of numerical inversion algorithms. In addition, it provides better insight into tracer transport mechanisms. Finally, it serves as a powerful tool of design and interpretation of tracer tests. All four objectives are illustrated in this work.  相似文献