爪式流体机械工作过程的三维数值模拟

分析了爪式流体机械的吸气、压缩、排气和混合过程的工作特性,对爪式流体机械工作过程中具有移动边界、包含啮合点和封闭工作腔的气体三维非定常可压缩流动进行数值模拟;得到各个时刻工作腔内的压力场、温度场和速度场的分布规律;得到吸气和排气过程中,吸气口处和排气口处的气体速度场变化规律。针对现有带尖点的爪式转予的不足,构建了一种新型圆弧爪式转子,改善了爪式转子的密封性能、受力变形和吸气性能,扩展了爪式流体机械的应用领域.     

爪极高温超导电动机研制

自从发现高温超导材料以来,以美国为主的许多国家都非常重视高温超导电动机的研制,高温超导电动机技术取得了很大的成就。提出了一种新的爪极高温超导电动机模型,详细介绍了样机的原理、结构及设计参数。     

爪式真空泵正弦线型三爪转子设计及数值模拟

爪式真空泵的转子型线决定其工作性能,现有的直线-圆弧型三爪转子存在组成曲线多、转子设计过程复杂的缺点。本文采用正弦线代替现有的直线-圆弧的组合曲线光滑地连接爪顶圆弧和爪底圆弧,进而提出了一种新型正弦线型三爪转子,并推导了其组成曲线的方程。对新型三爪转子真空泵的工作过程进行三维数值模拟,分析了内部流场的变化规律,并与现有三爪转子真空泵进行对比。研究结果表明:所提出的三爪转子具有型线简单、面积利用率高、压比大及气体阻力矩小的优点。     

五爪金龙、骨碎补的红外光谱分析

本文首次采用傅里叶变换红外光谱仪测定了云南当地的药材五爪金龙、骨碎补的红外光谱图,并对其进行了分析研究.通过对比,知两药材的红外光谱图非常相似,进一步对两药材的吸收峰分析,根据各种化学键和官能团振动所引起的吸收峰形状和范围,判断推理出两药材含有共同的物质:挥发油、苷类、三萜类化合物、糖类、脂肪等.此分析为两药材续伤止痛...     

新型遥爪星形聚合物的NMR表征

利用FT-NMR的¹H NMR及¹³C NMR技术对采用新型的膦-硅试剂直接引发的GTP反应合成的带有功能端基的遥爪星形聚合物进行表征,讨论了利用NMR技术确定星形遥爪聚合物的手臂数、分子量及链结构的可能性.     

微间隙受限液体行为与昆虫爪垫在光滑壁面的粘着机理

自然界中许多昆虫通过分泌一层油性液体薄膜实现其爪垫表皮和光滑壁面之间粘附和解粘附,从而实现在光滑壁布的快速爬行.为了提示昆虫爪垫与光滑壁面间微量液体薄膜对生物粘着的意义,基于自行研制的粘着接触实验仪,采用微量的[emim[Tf2N]离子液体和聚α烯烃油,观测其受限在纳米级光滑钢球表面与玻璃表面之间的接触行为以及法向粘着力.实验发现,临界体积(10^-12—10^-9L)范围内的受限液滴达到临界厚度（小于2μm）后会出现自动铺展和瞬时收缩行为，并同时提供幅值稳定且数值 关键词： 受限液体 粘着力 昆虫爪垫 类固化     

爪式真空泵新型圆弧直爪转子型线研究

爪式真空泵现有的直爪转子在爪顶处存在尖点,进而导致爪式转子啮合性能差、密封性能差、力学性能差等缺点;本文通过求解同步异向双回转运动规律下圆弧的共轭啮合型线,提出了一种新型无尖点的圆弧直爪转子型线;得到其生成方法和型线方程,研究了其型线的啮合关系,分析了爪尖圆弧半径对新型圆弧直爪转子性能的影响;并且对其工作过程进行数值模拟和对转子的受力进行计算,验证了新型圆弧直爪转子在工作性能和力学性能方面都优于现有带尖点的直爪转子。     

三爪式摆动架装置简介

<正> 一、引言在通常情况下,平面样板均用分离器来加工,而分离器又是靠三角架来带动或用(?)式     

微纳间隙受限液体的界面黏着机理研究

利用球-盘接触黏着试验仪对微量受限液体的界面黏着行为的研究发现：临界体积范围内（皮升到纳升）的受限液滴达到临界厚度后将出现自动铺展和瞬时收缩行为（分别对应球-盘趋进和分离过程）,并同时提供一定幅值的法向黏着力及伴随出现力的突变;该界面黏着力与液滴体积、球的直径等相关,并很好地揭示了昆虫或树蛙爪垫与光滑表面间的湿黏着行为.在进一步试验的基础上,利用球—面接触模型的毛细黏着力公式对所观察到的试验现象进行了机理揭示,认为临界体积受限液滴出现的自动铺展和瞬时收缩行为与接触副的刚度相关,最大法向黏着力随液体体积的减小而减小,与接触副之间受限液体的中心区厚度有关.结合生物黏着爪垫进行了受限液体界面黏着控制机理的分析,可以指导仿生黏着爪垫的设计与控制. 关键词： 生物黏着爪垫 毛细黏着力 受限液体     

两种游标卡尺的联系

游标卡尺是比刻度尺更精确的一种测量长度的工具，它的构造的主要部分是一条主尺和一条可以沿着主尺滑动的游标尺，也称游标．左测量爪固定在主尺上并与主尺垂直；右测量爪与左测量爪平行，固定在游标尺上，可以随同游标尺一起沿主尺滑动．     

爪式真空泵新型全光滑转子及其性能研究

针对爪式真空泵现有的爪式转子型线存在不光滑连接点的缺陷,本文提出了一种新型全光滑的爪式转子,其转子型线由6段圆弧和3段摆线的等距曲线组成,且能够实现正确的啮合;得到了其生成方法和型线方程。通过对其工作过程进行三维数值模拟,分析了全光滑爪式转子内部流场的变化规律,并与现有的爪式转子进行性能对比。研究结果表明:所提出的爪式转子具有啮合性能好、余隙容积小、力学性能好等优点。     

TGS—200/35型高速电影摄影机抓片爪加工工艺浅谈

TGS—200/35同步高速电影摄影机,是一种使用35毫米胶片的间歇抓片式高速电影摄影机,它的拍摄频率可达240帧/秒,同步拍摄频率最高200帧/秒。该机的间歇输片是靠双边六爪的抓片爪(见图)和双边四爪的定片针准确配合来实现的,而抓片爪设计与加工质量,是摄影机拍摄频率和画幅质量能否达到设计指标的关键因素。 TGS—200/35的抓片爪,几何形状复杂,尺寸精度和形位公差要求比较高。     

Revealing pion and kaon structure via generalised parton distributions

Clear windows onto emergent hadron mass(EHM)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distributions(GPDs).Beginning with algebraic GPD Ans?tze,constrained entirely by hadron-scaleπand K valence-parton distribution functions(DFs),in whose forms both EHM and Higgs boson influences are manifest,numerous illustrations are provided.They include the properties of electromagnetic form factors,impact parameter space GPDs,gravitational form factors and associated pressure profiles,and the character and consequences of allorders evolution.The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors;reveal that K pressure profiles are tighter than profiles,with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars;deliver parameter-free predictions for and K valence,glue,and sea GPDs at the resolving scale l=2GeV;and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom,with a similar statement holding for mass-squared radii.     

Phase relations in the ZnO-V2O5-K2O system

The subsolidus phase relations of a ZnO-V 2 O 5-K 2 O system are investigated by X-ray powder diffraction.There is 1 ternary compound,11 binary compounds and 14 three-phase regions in this system.The phase diagrams of V 2 O 5 K 2 O with the K 2 O content ranging from 0 to 71 mol% and pseudo-binary system of ZnO-K 2 ZnV 2 O 7 are also studied by X-ray powder diffraction and differential thermal analysis methods.     

Lax pair and vector semi-rational nonautonomous rogue waves for a coupled time-dependent coefficient fourth-order nonlinear Schrodinger system in an inhomogeneous optical fiber

Optical fibers are seen in the optical sensing and optical fiber communication. Simultaneous propagation of optical pulses in an inhomogeneous optical fiber is described by a coupled time-dependent coefficient fourth-order nonlinear Schr?dinger system, which is discussed in this paper. For such a system, we work out the Lax pair, Darboux transformation, and corresponding vector semi-rational nonautonomous rogue wave solutions. When the group velocity dispersion(GVD) and fourth-order dispersion(FOD) coefficients are the constants, we exhibit the first-and second-order vector semirational rogue waves which are composed of the four-petalled rogue waves and eye-shaped breathers. Both the width of the rogue wave along the time axis and temporal separation between the adjacent peaks of the breather decrease with the GVD coefficient or FOD coefficient. With the GVD and FOD coefficients as the linear, cosine, and exponential functions, we respectively present the first-and second-order periodic vector semi-rational rogue waves, first-and second-order asymmetry vector semi-rational rogue waves, and interactions between the eye-shaped breathers and the composite rogue waves.     

Gravitational collapse with standard and dark energy in the teleparallel equivalent of general relativity

A perfect fluid with self-similarity of the second kind is studied within the framework of the teleparallel equivalent of general relativity(TEGR).A spacetime which is not asymptotically flat is derived.The energy conditions of this spacetime are studied.It is shown that after some time the strong energy condition is not enough to satisfy showing a transition from standard matter to dark energy.The singularities of this solution are discussed.     

Breakdown voltage model and structure realization of a thin silicon layer with linear variable doping on a silicon on insulator high voltage device with multiple step field plates

Based on the theoretical and experimental investigation of a thin silicon layer(TSL) with linear variable doping(LVD) and further research on the TSL LVD with a multiple step field plate(MSFP),a breakdown voltage(BV) model is proposed and experimentally verified in this paper.With the two-dimensional Poisson equation of the silicon on insulator(SOI) device,the lateral electric field in drift region of the thin silicon layer is assumed to be constant.For the SOI device with LVD in the thin silicon layer,the dependence of the BV on impurity concentration under the drain is investigated by an enhanced dielectric layer field(ENDIF),from which the reduced surface field(RESURF) condition is deduced.The drain in the centre of the device has a good self-isolation effect,but the problem of the high voltage interconnection(HVI) line will become serious.The two step field plates including the source field plate and gate field plate can be adopted to shield the HVI adverse effect on the device.Based on this model,the TSL LVD SOI n-channel lateral double-diffused MOSFET(nLDMOS) with MSFP is realized.The experimental breakdown voltage(BV) and specific on-resistance(R on,sp) of the TSL LVD SOI device are 694 V and 21.3 ·mm 2 with a drift region length of 60 μm,buried oxide layer of 3 μm,and silicon layer of 0.15 μm,respectively.     

Phase properties of odd and even circular states

Phase properties of the even and odd circular states are studied within the Hermitian phase formalism of Pegg and Barnett. Exact analytical formulas for the distribution function and the variance of the phase operator are obtained and used to examine whether or not the even and odd circular states exhibit photon-number squeezing and phase squeezing.     

A new complex variable element-free Galerkin method for two-dimensional potential problems

In this paper, based on the element-free Galerkin (EFG) method and the improved complex variable moving least- square (ICVMLS) approximation, a new meshless method, which is the improved complex variable element-free Galerkin (ICVEFG) method for two-dimensional potential problems, is presented. In the method, the integral weak form of control equations is employed, and the Lagrange multiplier is used to apply the essential boundary conditions. Then the corresponding formulas of the ICVEFG method for two-dimensional potential problems are obtained. Compared with the complex variable moving least-square (CVMLS) approximation proposed by Cheng, the functional in the ICVMLS approximation has an explicit physical meaning. Furthermore, the ICVEFG method has greater computational precision and efficiency. Three numerical examples are given to show the validity of the proposed method.     

Neutron star cooling and GW170817 constraint within quark-meson coupling models

In the present work,we used five different versions of the quark-meson coupling(QMC)model to compute astrophysical quantities related to the GW170817 event and the neutron star cooling process.Two of the models are based on the original bag potential structure and three versions consider a harmonic oscillator potential to confine quarks.The bag-like models also incorporate the pasta phase used to describe the inner crust of neutron stars.With a simple method studied in the present work,we show that the pasta phase does not play a significant role.Moreover,the QMC model that satisfies the GW170817 constraints with the lowest slope of the symmetry energy exhibits a cooling profile compatible with observational data.