Hermite－Fejer型插值多项式的逼近阶

主要研究Ｈｅｒｍｉｔｅ－Ｆｅｊｅｒ型插值多项式Ｋｎ（ｆ；ｘ）逼近Ｃ１连续函数类时的逼近阶，改进了Ｈ．Ｈ．Ｇｏｎｓｋａ的结果［１］，并且证明了当ｆ（ｘ）∈Ｃ１［－１，１］时，对于特殊函数类Ｈ１ｗ，Ｋｎ（ｆ；ｘ）的逼近阶是不能改进的     

提高间接测量精度的方法

在实际的精密测量过程中,在现有指定仪器精度的基础上,将测量值尽量接近于真值,是我们目前最值得探讨的问题。本文从分析误差在计算过程中的传播系数开始讨论。１　误差产生的原因设ｘ１、ｘ２是Ｘ１、Ｘ２的最可信赖值,且Ｘ１、Ｘ２为独立变量,假设对Ｘ１、Ｘ２进行间接测量,那么函数Ｙ＝ｆ（Ｘ１,Ｘ２）在点（ｘ１,ｘ２）处的Ｔａｙｌｏｒ展开式为：ｆ（Ｘ１,Ｘ２）＝ｆ（ｘ１,ｘ２）＋［（ｆｘ１）,（Ｘ１－ｘ１）＋（ｆｘ２）,（Ｘ２－ｘ２）］＋１２！［（２ｆｘ２１）（Ｘ１－ｘ１）２＋２（２ｆｘ１…     

MS界面稳定性判据新探

给出了定向凝固平界面稳定性新的判据,（ｌ＋３ｋ／ｙ０）ξ ＋［１＋（１＋ ｋ）ｙ０／４ｋ］≥１其中Ａ为无量纲速度,ξ≡ＧＬＳ／ｍＧｃ,ｙ０是有关Ａ和ξ的一个二次方程的根．新判据的最大特点是可直接由凝固参数推断界面的稳定性,不用解高次方程．发现ＭＳ绝对稳定性速度Ｖａ仅在加权温度梯度ＧＬＳ→０时才是界面稳定性的临界速度．当 ＧＬＳ＞０时,Ｖａ大于实际的临界速度．给出了一个新的绝对稳定性梯度条件,并求出了最小的绝对稳定性无量纲临界梯度．     

泛连通图的一个充分条件

证明了如果Ｇ是３连通无爪图，且Ｇ的每个导出子图Ａ都满足（ａ１，ａ２），则Ｇ是泛连通图（除了ｕ，ｖ∈Ｖ（Ｇ），ｄ（ｕ，ｖ）＝１时，可能不存在（ｕ，ｖ）－ｋ路，２≤ｋ≤４外）     

NH4^＋对ZrO2超细粉性能的影响

本文介绍了ＺｒＯ２超细粉的制备工艺。在制备ＺｒＯ２超细粉时采用铵盐［（ＮＨ４）２ＳＯ４］作为添加剂，可以起到缓冲剂及络合剂的作用，改变了沉淀的表面电化学性质，并控制了沉淀终了时的ｐＨ值，认为如下结构胶团｛［Ｚｒ（ＯＨ）４］ｍｎ（ＯＨ－），（ｎ—ｘ）ＮＨ４＋｝ｘ－ｘ·ＮＨ４＋的生成是使ＺｒＯ２超细粉粒度变小的根本原因。     

关于图的奇因子

给出图Ｇ是（１，ｆ）－奇－消去图的一个充要条件和图Ｇ是（１，２ｎ－１）－奇－消去图的一个充分条件以及图Ｇ是（１，ｆ）－奇－覆盖图的一个充要条件。     

回归函数两类改良估计的Lp收敛性及收敛速度

设（Ｘ，Ｙ），（Ｘ１，Ｙ１），…，（Ｘｎ，Ｙｎ）为Ｒｄ×Ｒ１上的ｉｉｄ．随机向量，且Ｅ｜Ｙ｜＜∞。研究如何利用样本（Ｘ１，Ｙ１），…，（Ｘｎ，Ｙｎ）观测的结果估计回归函数ｍ（ｘ）＝Ｅ（Ｙ｜Ｘ＝ｘ），称为非参数回归函数估计问题。常用的估计有两类，一类是核估计，另一类是近邻估计。这两类估计都具有形式　这里（Ｗｎ１（ｘ），…，Ｗｎｎ（ｘ））是概率权向量，且每个Ｗｎｉ（ｘ）是依赖于ｘ，Ｘ１，…，Ｘｎ的Ｂｏｒｅｌ可测函数，对核估计和近邻估计，Ｗｎｉ（ｘ）有不同的定义方式（参看［６］）．最近，成平和赵林城在文献［４］、［５］中针对回归函数的核估计和近邻估计将ｍｎ（ｘ）作了改良，采用估计ｍ（ｘ），同时证明了它有强相合性并给出了收敛速度，本文接着讨论了这一问题，证明了ｍｎ（ｘ）具有Ｌｐ收敛性并给其Ｌｐ收敛速度。     

强光滑Banach空间的充要条件

本文的主要结论为，实Ｂａｎａｃｈ空间Ｘ是强光滑的当且仅当时任给ｘ０∈Ｓ（Ｘ），都存在ｐ，ｑ＞０，ｐ＋ｑ＝１使这里ｕｎ，νｎ∈Ｓ（Ｘ）∩Ｂ（ｘ０，ｒ）且ｕｎ≠νｎ，（ｎ＝１，２，…）．本文的结论比文［１］—［６］及［６］好。     

具有正负系数中立型时滞微分方程的振动性

考虑中立型时滞微分方程：［ｘ（ｔ）－Ｒ（ｔ）ｘ（ｔ－ｒ）］′＋Ｐ（ｔ）ｘ（ｔ－τ）－Ｑ（ｔ）ｘ（ｔ－σ）＝０其中Ｐ，Ｑ∈Ｃ（［ｔ０，∞），Ｒ＋］），Ｒ∈Ｃ（［ｔ０，∞），Ｒ）．ｒ，τ，σ∈Ｒ＋，文章中获得了上方程所有解振动的新判据，同时讨论了正解的存在性及非振动解的渐近性。     

Toda的纤维化与Selick的滤子化

目的是给出 Ｔｏｄａ Ｈ 的纤维化 Ｓ２ｎ－ １ → Ω Ｊｐ － １（ Ｓ２ｎ） Ｔ Ω Ｓ２ｐ－ １ 的又一新构造。文中说明映射 Ｔ 可以自然地由 Ｊａｍ ｅ Ｈｏｐｆ 的不变量 Ｈ ｐ ：Ω Ｓ２ｎ＋ １ →Ω Ｓ２ｎｐ＋ １ 直接导出。所提出的构造使得 Ｔ 成为一个 Ｈ 映射,由此得到 Ｓｅｌｉｃｋ 的滤子空间 Ｆ２ｋ （ｎ） 在奇素数ｐ 处具有指数ｐ ｎ＋ ｋ－ １ 。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.