蜂窝纸板剪切强度实验研究

研究了蜂窝纸板的剪切强度实验方法,实验测量与分析了温度、湿度、加载速率等因素对蜂窝纸板剪切强度的影响,给出了蜂窝纸板的剪切强度极限值.研究结果表明:随着加载速率的增加、温度的升高和湿度的降低,蜂窝纸板剪切强度都随之增加.     

蜂窝纸板平拉强度实验研究

研究了蜂窝纸板的平拉强度实验方法,实验测量与分析温度、厚度、加载速率等因素对蜂窝纸板平拉强度的影响.研究结果表明:试件厚度和环境的温度对蜂窝纸板的平拉强度有一定的影响,而加载速率对其影响不大.     

脱胶缺陷对蜂窝纸板侧压强度的影响

对含有脱胶缺陷的蜂窝纸板的侧压强度进行了试验研究;分析了蜂窝纸板在侧压栽荷作用下的变形特征及破坏现象;给出了含有脱胶缺陷的蜂窝纸板侧压强度的测量结果;分析了脱胶缺陷对蜂窝纸板侧压强度的影响.结果表明,对于面积为220mm×120mm蜂窝纸板试件而言,当缺陷直径≥8mm以后,侧压强度明显降低.     

AZ31B镁合金管材热态内压成形性能的研究

为了研究变形镁合金AZ31B管材的热态内压成形性能,通过单向拉伸测试了不同温度和应变速率下其力学性能的变化,通过胀形实验研究了温度对内高压成形性能的影响,以及相应变形条件下微观组织的变化.实验结果表明:在20～300℃时,AZ31B的屈服强度和抗拉强度随着温度的升高而降低,总伸长率随着温度的升高而提高,均匀伸长率随着温度的升高先增大后减小;当应变速率在0.001～0.1s-1时,屈服强度和抗拉强度随应变速率的增大而升高,总伸长率随着应变速率的增大而减小,均匀伸长率随着应变速率的增大先增加后减小;当温度在20～250℃时,镁合金管材的极限胀形率随温度的升高先增大后减小,在175℃时达到最大值.微观组织观察表明,175℃下不完全动态再结晶和孪晶两种微观组织的出现是使镁合金管材极限胀形率提高的主要原因.     

二次加载时蜂窝纸板的缓冲性能研究

依据蜂窝纸板初次压缩应力-应变曲线,设计了预压方案,研究了二次加载时蜂窝纸板的静态缓冲性能,并与初次加载时的缓冲性能进行了对比分析。结果表明:弹性预压对二次加载时缓冲系数曲线影响较小,塑性平台预压对缓冲系数曲线的影响较为显著;蜂窝纸板的最小缓冲系数随着预压量的增大而线性增大;弹性预压下,缓冲系数稳定时的应变随预压量的增加而增大,而塑性平台预压下,则随预压量的变大而减小;缓冲系数的波动幅度随预压量增加而逐渐减小,预压至塑性平台时,波动消失。研究为蜂窝纸板在多次冲击状况下的应用提供了理论基础。     

瓦楞／蜂窝复合结构纸板强度性能的试验研究

比较分析了瓦楞/蜂窝复合结构纸板的平压强度、边压强度、耐破度、戳穿强度等力学性能.结果表明,这种复合结构纸板的平压强度变化比较复杂,而它的边压强度、耐破度、戳穿强度均大于蜂窝纸板.     

成形温度和速度对单瓦钙塑板性能影响的实验研究

目的研究钙塑瓦楞的成形温度和速度对单瓦钙塑板的平压性能的影响。方法分别在实验速度为2.0,2.5,3.0,3.5,4.0 m/min和实验温度为130,140,150,160,170℃的情况下,用钙塑瓦楞机将钙塑片材压制成钙塑瓦楞芯纸,将不同成形温度和速度制成的钙塑瓦楞芯纸与牛皮面纸,用自制水基胶粘合成单瓦钙塑板并进行平压实验,最后对实验结果进行分析。结果不考虑温度的影响,当钙塑瓦楞成形速度为3.5 m/min时,平压强度为267 kPa,达到最大值;不考虑速度的影响,当钙塑瓦楞成形温度为130℃时,平压强度达到最大值272 kPa;当钙塑瓦楞成形温度为170℃时,平压强度达到最小值220kPa。将单瓦钙塑纸板与C型3层、BC型4层、BC型5层瓦楞纸板进行对比,单瓦钙塑纸板的平压强度超出3层瓦楞纸板平压强度202 kPa;超出4层瓦楞纸板平压强度123 kPa。结论随着钙塑瓦楞成形速度的增加,单瓦钙塑板的平压强度呈先骤增后缓增的趋势(最大值为266 kPa);随着钙塑瓦楞的成形温度的增加,单瓦钙塑板的平压强度总体呈减小趋势,但达到一定值(220 kPa)后不再减小。     

瓦楞纸板和蜂窝纸板的性能比较

<正>将面纸、芯纸相同,用纸量相同,芯层与面纸之间粘合的胶也相同的瓦楞纸板和蜂窝纸板做性能测试,测试结果如下:(1)蜂窝纸板的平压强度远高于瓦楞纸板,而且在耗材量一定的情况下,蜂窝纸板的平压强度随着孔径的增大而减少。     

蜂窝纸板在空投包装中的应用

目的研究蜂窝纸板在空投包装中的应用,构建军品绿色包装。方法通过研究蜂窝纸板的性能,并与瓦楞纸板进行比较,来分析蜂窝纸板在空投包装领域的应用效果及前景。结果蜂窝纸板密度小、抗弯刚度大、平压强度高、侧压强度高、缓冲性能好,是低碳可再生的绿色包装材料,可应用于空投平台、无伞空投物资、特殊包装等方面。结论蜂窝纸板可作为空投包装材料。     

瓦楞纸板和蜂窝纸板的性能比较

将面纸、芯纸相同,用纸量相同,芯层与面纸之间粘合的胶也相同的瓦楞纸板和蜂窝纸板做性能测试,测试结果如下：（1）蜂窝纸板的平压强度远高于瓦楞纸板,而且在耗材量一定的情况下,蜂窝纸板的平压强度随着孔径的增大而减少。     

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.     

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.……     

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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.