兰州重离子加速器深层治癌束流线真空系统

重离子深层治癌束流线从兰州重离子加速器冷却储存环(HIRFL-CSR)主环引出,利用能量为100MeV/u～430MeV/u的碳离子束,开展治疗体内各种癌症的深层治癌研究.该束流线真空系统包括极高真空段、超高真空段和大气段,采用不同的真空获得方案和工艺路线,分别在极高真空段和超高真空段获得了8×10-10Pa和1×10-6Pa的真空度,并顺利实现了束流线的真空过渡,保证了HIRFL-CSR主环极高真空系统的安全运行;研制了适用于高频率扫描磁铁内放置的真空管道,消除了涡流对束流的影响;对隔离真空和大气的大尺寸膜窗材料进行了调研,选择高强度塑料膜(Hostaphan)和加强纤维膜(Kevlar)联合使用,既能让束流通过,又不会产生危害人体的中子,并能够有足够的强度抵御大气压力.该束流线真空系统的建成为重离子深层治癌的研究提供了良好的真空条件.     

强流重离子加速器BRing-HFRS超高/极高真空过渡研究

针对强流重离子加速器(HIAF)中增强器(BRing)和放射性次级束流分离器(HFRS)之间的BRing引出线真空系统进行极高真空到超高真空的过渡研究。研究表明,为不使处于极高真空状态下的BRing环真空系统受到来自HFRS和高能束运线的影响,通过烘烤段加非烘烤段的方式以及快关阀的作用,可有效地解决真空系统从极高真空到超高真空的过渡问题,并且能够有效地起到对BRing主真空的保护作用。通过对BRing引出线真空系统进行真空压力分布的模拟计算,从侧面更加验证了真空过渡方案的可行性。     

大型重离子加速器真空系统及其挑战

中国科学院近代物理研究所从历次的大科学装置建设中,积累了大型真空腔体、超高/极高真空系统以及强流重离子加速器真空系统等设计经验。为了获得超高/极高真空系,从真空设备选择、材料处理、密封形式以及在线烘烤等方面形成了一套完整的工艺流程;在强流重离子加速器(High Intensity Heavy ion Accelerator Facility,HIAF)真空系统研制过程中,为了减小磁铁气隙尺寸,大幅度降低磁铁造价及电源运维成本,提出陶瓷内衬薄壁真空室新方法,并研制了原理性样机;为了有效控制HIAF未来运行过程中的动态真空效应,设计了束流准直器,开展了真空材料解吸率测量研究;为了解决高放射性区域真空系统的维护问题,提出了自重密封结构,同时研制了充气膨胀密封法兰;为了进一步优化高精度环形谱仪真空度,开展低温极高真空系统研究。     

兰州重离子冷却储存环10-10 Pa 大型超高真空系统

形成并成功地实施一套完整的超高真空获得方案,以满足兰州重离子加速器冷却储存环(HIRFL-CSL)6×10-9Pa超高真空度的要求.这套方案包括合理选择和配置真空排气系统及其他设备、合理选择材料、采用真空炉除气及在线烘烤等有效措施及大幅度降低材料出气率等.首先在样机上获得了5×10-10Pa的超高真空度,然后将样机的成功经验应用于HIR-FL-CSR大型超高真空系统.目前,已建成的各子系统真空度达到了(2×10-9～4×10-10)Pa.     

兰州重离子冷却储存环超高真空系统首台样机的研制

介绍了兰州重离子冷却储存环(HIRFL-CSR)超高真空系统首台样机的研制过程,给出了实验结果.介绍各真空室结构,对关键标准设备进行了测试与选型.根据实验结果估算出极限真空条件下材料的表面出气率;根据公式估算出钛升华泵的有效抽速并通过实验得到证实;对真空烘烤装置的初步工作也作了介绍.样机达到了3×10-9Pa的设计指标,结果表明HIRFL-CSR工程真空系统的设计方案是可行的.     

超高真空重离子加速器冷却储存环的焊接

结合超高真空对焊缝的要求,通过对板厚为2 mm的超高真空重离子加速器冷却储存环中一个零件的焊接工艺分析,总结了不锈钢超高真空容器薄壁件的焊接要点.     

超高/极高真空校准装置的研制

超高/极高真空校准装置由极高真空(XHV)系统、超高真空(UHV)系统、流量分流系统和供气系统四部分组成。使用磁悬浮涡轮分子泵和非蒸散型吸气剂泵组合抽气,在XHV校准室获得了10-10Pa的极高真空;提出了分流法校准真空规的方法,使校准下限延伸到10-10Pa;利用非蒸散型吸气剂泵对惰性气体无抽速的特性,使用惰性气体校准时,减小了校准下限的不确定度;提出了采用线性真空计测量激光小孔分子流流导的方法,减小了小孔流导的测量不确定度。校准装置复合了分流法、压力衰减法和直接测量法对真空规进行校准,压力校准范围为10-1Pa~10-10Pa,合成标准不确定度为0.41%~3.5%。     

HIRFL-CSR超高真空烘烤系统

为了满足兰州重离子加速器冷却储存环 6× 10 - 9Pa的真空度要求 ,必须建立温度在 2 0 0～ 30 0℃、控制良好的在线烘烤系统。主要从热电偶、加热器及绝热套 ;功率计算及分布 ;烘烤控制 ;样机测试结果等几个方面介绍兰州重离子加速器冷却储存环 (HIRFL- CSR)超高真空烘烤系统。     

超高/极高真空校准研究进展

本文概述了在超高/极高真空校准方面的研究进展.介绍了采用分子束法、压力衰减法、流导调制法以及分流法校准超高/极高真空规的原理、校准系统的结构及性能,并分析了它们的优缺点.从中可以看出,近年来随着真空材料处理技术、容器内表面处理技术和真空获得技术的进展,在10~(-10)Pa～10~(-8)Pa压力范围的超高/极高真空校准技术也取得了可喜的进展,校准系统的研制、维护成本日趋低廉,校准方法更为简单,校准结果更为准确.     

反射率计超高真空动密封馈入系统的研制

结合在NSRL同步辐射光束线和实验站的实际工作,对新设计的超高真空高精度同轴旋转平移差分馈入系统的密封型式和结构进行了描述,本系统可以完成超高真空条件下的高精度旋转平移轴系的馈入,已在NSRL反射率计实验站上得到成功使用.     

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.