Healing effectiveness of cracks rehabilitation in reinforced concrete using electrodeposition method

An electrodeposition method and its experimental device for rehabilitation of cracks in reinforced concrete were proposed. Porous concrete is proposed to simulate cracked concrete, and mass increment, permeation coefficient and sound velocity of ultrasonic wave were used to be evaluating indicators of healing effectiveness of crack rehabilitation in this method. Effect of currency density, concentration of electrolyte solution on healing effectiveness of porous reinforced concretes with different total void ratio was studied. The experimental results indicate that the simulation of porous concrete for cracks can reflect the healing effectiveness of electrodeposition method effectively, Total void ratio of porous concrete has little effect on healing effectiveness of electrodeposition at early ages. The higher the currency density or concentration of electrolyte solution is, the higher the electrodeposition rate and sound velocity in porous concrete are, and the lower the permeation coefficient of porous concrete will be. Mg（OH）2 crystals produced in high current density are large, thin sheet-shaped and arranged loosely.     

服装裁剪机高速钢直刀片真空热处理技术研究

W6Mo5Cr4V2钢板经冲裁加工制成的刀片,用盐浴油淬、低温回火后,经磨削工艺去除盐渍油污,耗时又费材。然而,采用光亮真空热处理及抛光加工技术替代传统的用盐浴油淬和磨削技术生产服装裁剪机用刀片,研究其真空热处理工艺参数,分析其组织和性能,可以降低材料的消耗和生产成本,提高产品质量。     

Cracks coalescence mechanism and cracks propagation paths in rock-like specimens containing pre-existing random cracks under compression

The mechanism of cracks propagation and cracks coalescence due to compressive loading of the brittle substances containing pre-existing cracks （flaws） was modeled experimentally using specially made rock-like specimens from Portland Pozzolana Cement （PPC）. The breakage process of the specimens was studied by inserting single and double flaws with different inclination angles at the center and applying uniaxial compressive stress at both ends of the specimen. The first crack was oriented at 50＆#176; from the horizontal direction and kept constant throughout the analysis while the orientation of the second crack was changed. It is experimentally observed that the wing cracks are produced at the first stage of loading and start their propagation toward the direction of uniaxial compressive loading. The secondary cracks may also be produced in form of quasi-coplanar and/or oblique cracks in a stable manner. The secondary cracks may eventually continue their propagation in the direction of maximum principle stress. These experimental works were also simulated numerically by a modified higher order displacement discontinuity method and the cracks propagation and cracks coalescence were studied based on Mode I and Mode II stress intensity factors （SIFs）. It is concluded that the wing cracks initiation stresses for the specimens change from 11.3 to 14.1 MPain the case of numerical simulations and from 7.3 to 13.8 MPa in the case of experimental works. It is observed that cracks coalescence stresses change from 21.8 to 25.3 MPa and from 19.5 to 21.8 MPa in the numerical and experimental analyses, respectively. Comparing some of the numerical and experimental results with those recently cited in the literature validates the results obtained by the proposed study. Finally, a numerical simulation was accomplished to study the effect of confining pressure on the crack propagation process, showing that the SIFs increase and the crack initiation angles change in this case.     

加气混凝土墙面抹灰空裂原因分析及防治措施

通过对加气混凝土墙面抹灰的空裂原因分析，提出了操作简单，技术可靠的防治措施。     

气-气热管换热器在电站余热回收中的应用

分析了气-气热管换热器的技术经济性能,并对气-气热管换热器在电站余热回收应用方面的优点及注意事项进行了探讨。     

地铁排热回收热泵系统的技术经济性分析

利用热泵系统对地铁排热进行回收用于供暖是一项新的节能技术，通过应用经济评价方法，比较分析了热泵系统三种不同辅助热源的经济参数，得出总供暖容量1500kw，辅助热源采用燃气炉的热泵系统为最佳的结论．     

我国机械类热处理现状及发展

叙述了我国热处理技术现状，指出应推广应用少无氧化、节能和清洁的热处理技术，实现热处理设备的自动化，生产专业化，研究应用金属计算科学、重点开发推广可控气氛热处理及真空热处理。     

Influence of Mineral Admixtures on the Electrodeposition Healing Effect of Concrete Cracks

Two types of solutions(Zn SO4, Mg SO4) were selected to study the influence of mineral admixtures on the electro-deposition healing effect of concrete cracks. Four parameters(i e, rates of weight gain, surface coating, crack closure and crack filling depth) were measured. The mineral composition of electro-deposits in the cracks was analyzed. The study shows that the healing effect of mortar specimens with 10% fly ash is the worst, while the healing effect of mortar specimens with 20% fly ash is better than that of the specimens without fly ash. The rates of weight gain, surface coating, crack closure and crack filling depth decrease with increasing content of the ground granulated blast-furnace slag(GGBS). The mineral admixtures have no influence on the composition of deposits.     

一种工业锅炉排渣热利用方案

针对大型供热链条锅炉排渣量大,排渣温度高,排渣无热利用措施,灰渣冷却水因汽化耗量大以及汽化蒸汽对锅炉房内的土建结构和设备腐蚀等问题,提出了一种工业锅炉排渣余热利用方案,介绍了该方案的系统构成,工作原理,分析了节能减排效果。     

真空热处理对热障涂层组织形貌及元素扩散的影响

为了研究真空热处理对CoNiCrAlY涂层组织形貌及元素扩散的影响,采用超音速火焰喷涂(HVOF)设备在镍基高温合金基体上制备了CoNiCrAlY涂层.对部分样品进行真空热处理,利用大气等离子喷涂8YSZ陶瓷层.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱分散谱仪(EDS)等分析了热障涂层的相组成、微观组织、元素扩散与热震性能,研究了真空热处理对热障涂层的影响.结果表明,真空热处理后,CoNiCrAlY涂层颗粒间界面消失且涂层发生均质化;涂层与基体界面处元素发生扩散;热障涂层的抗热震性能提高.     

混凝土裂缝的预防与处理

阐述了混凝土工程中一些常见的裂缝问题，并针对具体情况提出了一些预防措施和几种常用的处理方法。原则上应为预防重于处理．目的是延长工程的使用寿命。     

矩形钢筋混凝土蓄水池裂缝的成因分析

文章分析了蓄水池裂缝的成因,提出了在设计、施工中采取的措施。     

Enhancing the crystalline degree of carbon nanotubes by acid treatment, air oxidization and heat treatment

Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect.Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.     

超薄型高速钢片铣刀的热处理

文中对厚度小于０．２０ｍｍ的超薄型高速钢片铣刀的热处理工艺进行了探讨，实践证明，对超薄型高速钢片铣刀采用套筒法进行等温处理是一种性能可靠。操作简便、经济易行的热处理工艺．     

C6-3．43／0．98机组低真空供热改造的热经济性分析

本通过承德市热电厂C6—3．43／0．98机组低真空供热改造前后各项热经济指标的对比,分析了低真空供热的热经济性。     

热处理对705铝合金板应力腐蚀性能的影响

采用了多种热处理工艺对７０５铝合金板应力腐蚀性能进行了研究,结果表明,原供货态的７０５铝合金板短横向抗应力腐蚀性能较低采用新的热处理工艺可在强度与原供货态相当的情况下,显著地提高７０５铝合金板的抗应力腐蚀性能。     

Influence of deformation and heat treatment on electrical conductivity of CuMoCr alloy

The solution heat treatment,cold deformation and subsequent aging were performed on CuMoCr alloy.And the influence of deformation and aging treatment on the electrical conductivity of CuMoCr alloy was studied through metallograph,transmission electron microscopy(TEM) and electrical conductivity measurement.Results show that deformation without subsequent aging can reduce the electrical conductivity of CuMoCr alloy,but deformation followed by the optimum aging treatment can effectively improve the electrical conductivity of CuMoCr alloy.Aging at 500 ℃ for 4 h after 80% deformation,the much better electrical conductivity of CuMoCr alloy can be obtained.Reduction of Cr content in the Cu matrix could be the reason for the enhancement of electrical conductivity.     

Effect of heat treatment method on microstructure of tailings glass ceramics

A Cao-Mgo-Al2O3-SiO2 quaternary system was established with the main crystal phase design based on Diopside, and the effect of once-through sintering heat treatment on microstructure of iron railings glass ceramics was studied by using DTA, SEM along with measurement of microhardness and volume density. The experimental results show that, when the total amount of FeO and Fe2O3 exceeds 10wt%, a large number of fine nuclei are produced in the annealing process, and the phenomenon of nucleus resorption happens during the process of nucleation heat treatment, which is unfavorable for preparing iron tailings glass ceramics through once-through sintering method. When the annealing temperature from 1250 ℃ to 830 ℃, setting crystallization time for 4h, without heat treatment, crystals are well grown with arrangement and interlocking in glass phase. At 830 ℃ the crystals are well developed, well distributed and of good size; with crystallization time of 4 h the crystals with radial shape have high content and regular arrangement.     

热处理对一种两相钛合金超塑性及组织的影响

对经不同制度处理的一种富β的α+β型钛合金(SPZ)的超塑性性能及组织进行了研究.结果表明,700℃/1 h AC处理后,合金具有良好的室高温性能;应变速率高达1.11×10-3/s时,合金在740℃~800℃温度范围内显示出超塑性,超塑拉伸延伸率均超过1600%;760℃,合金拉伸延伸率可高达2149%.扫描电镜(SEM)观察发现,SPZ合金的变形行为具有明显细晶超塑性的特点.应变速率为2.22×10-3/s时,740℃、780℃变形后晶粒尺寸分别为1.51mm3、.21 mm.超塑变形后合金的晶粒尺寸比变形前的有所增大;超塑性温度越高,晶粒长大程度越高.     

砌体结构裂缝成因及处理

分析了砌体结构裂缝的成因,对温度裂缝、沉降裂缝的产生机理进行了分析,讨论了影响砌体结构开裂的因素。针对不同裂缝提出了相应处理措施。