检索结果-南通市图书馆

贵州罗甸玉“麻点”和“草花”的物质组成及成因研究

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

光谱学与光谱分析 2024年第11期44卷 3236-3243页

作者：张可轩于海燕柏鹤张予烨桂林理工大学地球科学学院广西隐伏金属矿产勘查重点实验室

选取带有“麻点”和“草花”花纹的贵州罗甸透闪石玉（罗甸玉）为研究对象，利用扫描电镜、电子探针和激光拉曼光谱仪测试技术，探讨罗甸玉中“麻点”和“草花”的物质组成和成因。测试结果表明：大的团块状“麻点”分布在部分方解石和... 详细信息

选取带有“麻点”和“草花”花纹的贵州罗甸透闪石玉（罗甸玉）为研究对象，利用扫描电镜、电子探针和激光拉曼光谱仪测试技术，探讨罗甸玉中“麻点”和“草花”的物质组成和成因。测试结果表明：大的团块状“麻点”分布在部分方解石和透闪石的交界处或透闪石晶界处，小的片状“麻点”分布在方解石或透闪石的小的孔洞中。“麻点”的扫描电镜能谱和电子探针成分分析结果表明其由铁氧化物组成，拉曼光谱特征峰显示为赤铁矿。“草花”呈“沙漠玫瑰”的团球状或无定形状存在于两种结构透闪石交界处或柱状、片状透闪石的边缘。“草花”的扫描电镜能谱和电子探针成分分析结果表明其为锰氧化物，拉曼光谱特征峰显示为钙锰矿(640、 356和287 cm-1)或水钠锰矿(636、 582和506cm-1)。依据带有“麻点”和“草花”花纹的罗甸玉的成分和结构特征可以推测：罗甸玉中大的团块状“麻点”是后期富含Fe的热液与透闪石玉成矿热液混染成矿，而小的片状“麻点”则由富Fe热液充填形成。“草花”周围呈浸染状的叶片状或柱状透闪石是由富Mn热液与透闪石玉成矿热液混合结晶形成Mn含量比较高的透闪石，后期富Mn热液运移到柱状或片状透闪石的边缘或裂隙处析出形成钙锰矿或水钠锰矿。

关键词：罗甸玉麻点草花成分微形貌

Master equation,design equations and runaway speed of the Kaplan turbine

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第2期33卷 282-300页

作者： zh.zhang zhAW Zurch University of Applied ScienceZurichSwitzerland

To make the Kaplan turbine technology comparable to both the Pelton and the Francis turbine,the master equation for the Kaplan turbine has been established by analyses similar to that-for the Francis *** analysis begins with the descriptions of free vortex flows at the runner inlet and the swirl flow at the impeller *** considering the Euler equation for specific work and by further evaluating the most significant shock and swirling losses,the first and the second energy equations in the form of hydraulic efficiency were *** master equation is then established by combining both energy *** addition,three design equations and a new design parameter are *** master equation relates the turbine hydromechanics to the geometrical design of both the runner and the guide-vane *** enables the complete hydraulic characteristics of a given Kaplan turbine to be analytically and simply computed.A computation example demonstrates the functionality and applicability of the *** the reconstructed master equation,the runaway speed of the Kaplan turbine and its dependence on the guide-vane setting can be easily and precisely *** bulb turbines with guide vanes directly ahead of the turbine runner in the same tube,all computations are also applicable using another equivalent control parameter.

关键词： Kaplan turbine master equation design equations design parameter runaway speed hydraulic efficiency shock loss swirling loss bulb turbines

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

“如果”句功能的类型学考察

汉语学习 2024年第2期 22-32页

作者：吴炳章姜彩璨许冰中国海洋大学外国语学院山东青岛266100

“如果”句的语义结构和用法复杂多样,但学界对该结构的功能类型分析过于笼统。文章通过语料库梳理书面语中“如果”句的结构特点和语篇关系,对其进行了功能分类。从功能视角看,“如果”句在知识域、语言域和人际域中分别发挥前提限定... 详细信息

“如果”句的语义结构和用法复杂多样,但学界对该结构的功能类型分析过于笼统。文章通过语料库梳理书面语中“如果”句的结构特点和语篇关系,对其进行了功能分类。从功能视角看,“如果”句在知识域、语言域和人际域中分别发挥前提限定、语篇建构和会话修辞等功能。根据从句和主句的意义关系,“如果”句可以分为蕴含条件句和非蕴含条件句。各类“如果”句的功能各有句法语义特征。从各类“如果”句的用法分布看,“如果”句的主要功能是表达推理关系,其次是语篇关系,再次是话语修辞。

关键词： “如果”句假设条件句间接条件句

Master equation and runaway speed of the Francis turbine

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2018年第2期30卷 203-217页

作者： zh.zhang Free Researcher Zurich Switzerland

The master equation of the Francis turbine is derived based on the combination of the angular momentum（Euler） and the energy laws. It relates the geometrical design of the impeller and the regulation settings（guide vane angle and rotational speed） to the discharge and the power output. The master equation, thus, enables the complete characteristics of a given Francis turbine to be easily computed. While applying the energy law, both the shock loss at the impeller inlet and the swirling loss at the impeller exit are taken into account. These are main losses which occur at both the partial load and the overloads and, thus, dominantly influence the characteristics of the Francis turbine. They also totally govern the discharge of the water through the impeller when the impeller is found in the standstill. The computations have been performed for the discharge, the hydraulic torque and the hydraulic efficiency. They were also compared with the available measurements on a model turbine. Excellent agreement has been achieved. The computations also enable the runaway speed of the Francis turbine and the related discharge to be determined as a function of the setting angle of the guide vanes.

关键词： Francis turbine master equation runaway speed hydraulic efficiency shock loss swirling loss streamline similarity method

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2018年第1期30卷 140-152页

作者： zh.zhang Free Researcher Zurich Switzerland

An analytical method is presented, which enables the non-uniform velocity and pressure distributions at the impeller inlet of a pump to be accurately computed. The analyses are based on the potential flow theory and the geometrical similarity of the streamline distribution along the leading edge of the impeller blades. The method is thus called streamline similarity method（SSM）. The obtained geometrical form of the flow distribution is then simply described by the geometrical variable G（s） and the first structural constant G_Ⅰ. As clearly demonstrated and also validated by experiments, both the flow velocity and the pressure distributions at the impeller inlet are usually highly non-uniform. This knowledge is indispensible for impeller blade designs to fulfill the shockless inlet flow condition. By introducing the second structural constant G_Ⅱ, the paper also presents the simple and accurate computation of the shock loss, which occurs at the impeller inlet. The introduction of two structural constants contributes immensely to the enhancement of the computational accuracies. As further indicated, all computations presented in this paper can also be well applied to the non-uniform exit flow out of an impeller of the Francis turbine for accurately computing the related mean values.

关键词： Pumps streamline similarity method flow distribution shock loss structural constant

SUBSTRUCTURE PRECoNDITIoNERS FoR NoNCoNFoRMING PLATE ELEMENTS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1998年第4期16卷 289-304页

作者： Shi, ZC Xie, zh Chinese Acad Sci ICMSEC State Key Lab Sci & Engn Comp Beijing 100080 Peoples R China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100080 Peoples R China

In this paper, we consider the problem of solving finite element equations of biharmonic Dirichlet problems. We divide the given domain into non-overlapping subdomains, construct a preconditioner for Morley element by substructuring on the basis of a function decomposition for discrete biharmonic functions. The function decomposition is introduced by partitioning these finite element functions into the low and high frequency components through the intergrid transfer operators between coarse mesh and fine mesh, and the conforming interpolation operators. The method leads to a preconditioned system with the condition number bounded by C(1 + log(2) H/h) in the case with interior cross points, and by C in the case without interior cross points, where H is the subdomain size and h is the mesh size. These techniques are applicable to other nonconforming elements and are well suited to a parallel computation.

关键词： substructure preconditioner biharmonic equation nonconforming plate element

MULTIGRID METHoDS FoR MoRLEY ELEMENT oN NoNNESTED MESHES

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1998年第5期16卷 385-394页

作者： Shi, ZC Xie, zh Chinese Acad Sci ICMSEC State Key Lab Sci & Engn Comp Beijing 100080 Peoples R China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100080 Peoples R China

In this paper, we consider some multigrid algorithms for the biharmonic problem discretized by Morley element on nonnested meshes. Through taking the averages of the nodal variables we construct an intergrid transfer operator that satisfies a certain stable approximation property. The so-called regularity-approximation assumption is then established. optimal convergence properties of the W-cycle and a uniform condition number estimate for the variable V-cycle preconditioner are presented. This technique is applicable to other nonconforming plate elements.

关键词： multigrid method Morley element nonnested meshes

Laser and Fluorescence Properties of organic Dye DCM Doped Sol-Gel-Derived Solid-State Materials

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1999年第6期15卷 563-566页

作者： zhang, QY Jiang, zh Tongji Univ Pohl Inst Solid State Phys Shanghai 200092 Peoples R China Chinese Acad Sci Shanghai Inst Opt & Fine Mech Shanghai 201800 Peoples R China

Two kinds of new ormosil xerogels derived from GPTMS (3-glycidyl propyl trimethoxisilane) and TEoS (tetraethoxysilane) or GPTMS and Ti(oBu)4 (tetrabutoxytitanate) were synthesized viathe sol-gel method as dye laser host. Their optical properties, microstructure characteristics and sudece laser damage thresholds have been reported. The effects of dye matrix combination on the fluorescence emission, slope efficiency, photostability and tunable bandwidth were *** oscillation was easily achieved near 620 nm with a slope efficiency of 29% from DCM dopedSio2-ormosil pumped by a frequency-doubled radiation from a Q-switched Nd:YAG laser. The laser wavelength was tunable over 59 nm, and the laser output energy had only a 10% reduction after 2.5× 104 pulses at a pump repetition rate of 1Hz and a pump intensity of 1

关键词： GPTMS DCM EtoH

Corneal ulcer caused by nocardia brasiliensis in a patient with diabetes

在线全文

学校读者我要写书评

暂无评论

International Journal of ophthalmology(English edition) 2014年第2期7卷 381-383页

作者： Xian-Ning Liu Na An Jie Wu kun Xu Xiu-Ping zh Sheng-Li Mi Department of ophthalmology the First Hospital of Xi'an Shaanxi Provincial Key Laboratory of ophthalmology Ophthalmological Institute of Shaanxi Province Biomanufacturing Engineering Laboratory Graduate School at Shenzhen Tsinghua University

Dear Sir,Iam ***-Li Mi,from the Biomanufacturing engineering laboratory,Graduate School at Shenzhen,Tsinghua University,Shenzhen,China.I write to present a case report of nocardia brasiliensis in a patient with *** is part of a group of aerobic actinomycetes,widely distributed in *** asteroids and nocardia brasiliensis are the most common human *** infected by nocardia asteroids through the respiratory tract mainly suffer from primary suppurative pulmonary *** of nocardia brasiliensis often occurs in the advanced stages of a progressive disease or immune disorder,especially Cushing syndrome,diabetes,or in patients using corticosteroids,immunosuppressive agents and broad-spectrum antibiotics for long time[1].To our knowledge,the reports of nocardia keratitis was very rare

关键词： Corneal ulcer caused by nocardia brasiliensis in a patient with diabetes