500 kV高压线下预应力钢筋混凝土桥拆除爆破

根据待拆桥梁结构特点和周围环境情况,采用控制爆破技术对500 kV高压线下现浇预应力钢筋混凝土箱梁桥进行拆除爆破。在确定桥梁的爆破方案和区域划分的基础上,针对桥梁墩柱、箱梁及桥台各自结构特点,制定不同的爆破参数、装药结构、起爆网路和安全防护措施,控制了爆破的危害效应,达到了预期的爆破效果,为类似条件下的桥梁工程拆除爆破提供参考。     

500 kV高压线下预应力钢筋混凝土桥拆除爆破

根据待拆桥梁结构特点和周围环境情况,采用控制爆破技术对500kV高压线下现浇预应力钢筋混凝土箱梁桥进行拆除爆破。在确定桥梁的爆破方案和区域划分的基础上,针对桥梁墩柱、箱梁及桥台各自结构特点,制定不同的爆破参数、装药结构、起爆网路和安全防护措施,控制了爆破的危害效应,达到了预期的爆破效果,为类似条件下的桥梁工程拆除爆破提供参考。     

通航航道上千米预应力箱梁桥梁拆除爆破

为了顺利拆除全长1 572.44 m,航道上410 m主桥段为国内罕见的“空心桥墩+空心桩基+预应力箱梁”结构的石龟山老桥,通过对比静力切割方法和爆破方法,得出主桥采用静力切割方法拆除施工风险大,拟采用爆破拆除方法。结果表明：采用桥面爆破、桥墩爆破与桩基爆破相结合的施工工艺,以及水压爆破与钻孔爆破相结合的综合技术,主桥桥墩实施水压爆破,箱梁分段解体爆破,采用复式交叉起爆网路和复合防护方式,达到良好的爆破效果,可为类似桥梁的拆除提供了很好的借鉴作用。     

水压爆破拆除钢筋砼箱梁

介绍一例水压爆破拆除钢筋砼箱梁的爆破方案、参数设计、装药结构及安全防护，并对爆破效果进行分析。     

复杂环境下城市超长高架桥精细爆破拆除关键技术研究

针对复杂环境下城市高架桥爆破拆除工程的特点,提出了其精细爆破的关键技术。提出采用墩柱爆后钢筋骨架的初弯曲压杆失稳力学模型和高架桥连续塌落动力学模型等进行关键参数的定量化设计,运用水压爆破技术对多室箱梁进行爆破破碎,采用"宽间隔、长延时、互动有序"非电接力交叉复式起爆网路可确保超长延时起爆网路的安全准爆,采用物理模型试验方法对爆破方案、关键参数等的合理性进行验证,采用多种综合防护技术进行有害效应的预测与控制,采用专业化、协同化、精细化、执行力(SCPE)的项目管理方法进行爆破拆除工程的精细管理。该精细爆破关键技术可为复杂环境下城市高架桥爆破拆除工程实践提供参考。     

胶州湾高速环太原路立交桥水压爆破拆除

被爆破拆除的立交桥为连续箱梁结构,在爆破设计中采用了将桥体进行水压爆破与立柱进行常规爆破相结合的方案.重点介绍了水压爆破的计算方法、实际爆破参数及具体施工过程.此次水压爆破取得了理想的爆破效果,加快了爆后胶州湾高速的清运速度,此计划提前9h通车.为今后类似工程的设计施工提供了参考.     

连续箱梁临时支座预留孔爆破拆除方法

以前 ,采用硫磺砂浆热熔法拆除悬浇箱梁临时支座 ,效果不理想 ,耗时费力。在广珠西线橹尾橇特大桥主桥连续箱梁临时支座的拆除中 ,采用了预留孔的爆破方法 ,破碎效果好 ,拆除速度快。本文介绍了爆破设计的原则、药量计算、炮孔布置、起爆网路和安全措施。此外 ,还介绍了利用PVC管预留炮孔的施工方法     

深水钢围堰基坑水下爆破设计与施工

田家坪舞水河特大桥是新建长沙至昆明铁路客运专线湖南段的重点项目,主桥采用大跨度连续箱梁结构,7#主墩桩基、承台采用圆形双壁钢围堰施工,为将双壁钢围堰下沉就位,需进行基坑水下爆破施工。对该基坑进行了水下爆破设计与施工。实践证明,该水下爆破设计合理、施工方便,可为类似工程提供借鉴和参考。     

深水钢围堰基坑水下爆破设计与施工

田家坪舞水河特大桥是新建长沙至昆明铁路客运专线湖南段的重点项目,主桥采用大跨度连续箱梁结构,7#主墩桩基、承台采用圆形双壁钢围堰施工,为将双壁钢围堰下沉就位,需进行基坑水下爆破施工。对该基坑进行了水下爆破设计与施工。实践证明,该水下爆破设计合理、施工方便,可为类似工程提供借鉴和参考。     

沪蓉西高速野三河特大桥施工期爆破振动测试与分析

确定爆破振动作用下桥梁的振动速度分布规律对保证新浇筑特大桥的安全具有重要意义.根据沪蓉西高速野三河水电站爆破振动试验中在野三河特大桥桥梁部位的振动监测数据,分析了爆破振动作用下新浇筑野三河特大桥的振动速度响应特性,结果表明,试验条件下,桥梁的振动主频率较低,主频一般在10-40 Hz,大桥箱梁振动速度相对桥墩基础具有明显的放大,放大系数一般在1.5-2.5倍之间.     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to