特粗WC颗粒的制备方法研究

在研究当前国内外制备超粗WC粉末各种方法的基础上,提出了一种制备特粗WC颗粒的方法。使用由国产高纯单晶W颗粒破碎得到的Fsss>50μm的W颗粒进行高温碳化来制取特粗WC颗粒。采用扫描电镜(SEM)、电感耦合等离子发射光谱(ICP-AES)、X射线衍射(XRD)等分析测试手段,研究了W颗粒和WC颗粒的形貌、粒度,以及所制备WC的含碳量。结果表明,最终得到的WC颗粒大小分布均匀,化合碳含量高,游离碳含量很低,最大Fsss粒度可达到70μm以上。     

钽喷丝头表面覆加金刚石膜的研究

为改善钽喷丝头的品质,提高其硬度和耐碱腐蚀能力,利用热丝CVD制备不同粒径的金刚石薄膜,并通过对钽衬底的碳化处理,成功使之沉积于纯钽啧丝头表面,对纯钽喷丝头进行表面强化.通过场发射扫描电镜观察,大粒径金刚石薄膜有少量孔隙,小粒径金刚石薄膜细腻致密.硬度测试结果表明,金刚石薄膜钽喷丝头表面硬度达HV1 000以上,远高于纯钽及其它工艺处理后的钽喷丝头.可纺性试验结果表明,其性能都达到或超过传统喷丝头,完全可以取代成本高昂的铂金喷丝头.     

三峡工程混凝土的耐久性

三峡工程混凝土配合比设计已从传统的按强度设计转变为按耐久性设计。通过掺用优质外加剂和掺和料 ,降低了混凝土绝热温升 ,提高了混凝土的抗冻、抗裂和碳化性能 ,并采取了限制原材料碱含量和混凝土总碱量等碱骨料反应预防措施 ,从而确保了三峡工程混凝土的耐久性。     

已有钢筋混凝土框架结构的抗震可靠度分析

提出已有钢筋混凝土框架结构抗震可靠度分析的一种实用方法,取最小的楼层可靠度作为结构的可靠度;利用构件的荷载/抗力比,并考虑其他修正系数的办法构造权函数,将各构件的可靠度组合成楼层的可靠度;根据震害经验,以柱的抗剪能力建立钢筋混凝土框架结构的抗震功能函数;对混凝土碳化和结构荷载的影响因素进行分析。并对一个工程实例进行分析,分别计算出原结构及采用三种不同方法加固方案后的结构抗震可靠度。     

泵送混凝土的碳化及施工抑制措施的试验研究

通过试验和实际工程中应用,找出了泵送混凝土碳化的影响因素,确定了施工抑制措施,总结出了不同龄期泵送混凝土的合理碳化深度值,对保证泵送混凝土的耐久性和建筑物的合理使用寿命有长远的经济效益和社会效益.     

碳化法制备球状碳酸钙

介绍了球状碳酸钙的两种生产方法，利用碳化法制备了球状碳酸钙，讨论了添加剂，碳化温度，二氧化碳浓度和氢氧化钙浓度对产物的影响，通过正交试验，获得了制备球状碳酸钙的适宜条件。     

Synthesis and performances of bio-sourced nanostructured carbon membranes elaborated by hydrothermal conversion of beer industry wastes

Hydrothermal carbonization (HTC) process of beer wastes (Almaza Brewery) yields a biochar and homogeneous carbon-based nanoparticles (NPs). The NPs have been used to prepare carbon membrane on commercial alumina support. Water filtration experiments evidenced the quasi-dense behavior of the membrane with no measurable water flux below an applied nitrogen pressure of 6 bar. Gas permeation tests were conducted and gave remarkable results, namely (1) the existence of a limit temperature of utilization of the membrane, which was below 100°C in our experimental conditions, (2) an evolution of the microstructure of the carbon membrane with the operating temperature that yielded to improved performances in gas separation, (3) the temperature-dependent gas permeance should follow a Knudsen diffusion mechanism, and (4) He permeance was increasing with the applied pressure, whereas N₂ and CO₂ permeances remained stable in the same conditions. These results yielded an enhancement of both the He/N₂ and He/CO₂ permselectivities with the applied pressure. These promising results made biomass-sourced HTC-processed carbon membranes encouraging candidates as ultralow-cost and sustainable membranes for gas separation applications.     

预防混凝土早期开裂及过早碳化的技术措施

本文参考国内外资料,阐述了现阶段混凝土开裂及过早碳化的原因、危害和一般防治方法。     

氨浸 - 碳化法制活性氧化锌

对以菱锌矿为原料，用硫化碱为除杂剂，二氧化碳为沉锌剂的活性氧化锌制备方法进行了研究，重点考察了除杂和碳化沉锌过程的工艺条件，实验得出，除杂时硫化碱加入量为理论量的120％较好；碳化沉锌终点定在pH值为8时较为适宜；碳化时采用较低的温度，较高的二氧化碳浓度和较高的空塔气速（0．04－0．05m/s)为宜。     

The carbonization of colloidal polyaniline nanoparticles to nitrogen‐containing carbon analogues

The carbonization of nanostructures afforded by conducting polymers represents a new route to the preparation of functional nanostructured carbons. The exposure of colloidal polyaniline particles stabilized with poly(N‐vinylpyrrolidone) or silica nanoparticles at 650 °C in inert atmosphere led, in both cases, to nitrogen‐containing carbonaceous materials with specific surface areas of 200 and 205 m² g^?1, respectively, and conductivities of 8.3 × 10^?7 and 1.9 × 10^?10 S cm^?1, respectively. The latter material contained 77 wt% of silica. The original particulate nanostructure of the samples was preserved after carbonization. The carbon‐to‐nitrogen atomic ratio was 7.2 and 7.9; the nitrogen content in the carbonized polyaniline–poly(N‐vinylpyrrolidone) particles was 10.8 wt%. Thermogravimetric analysis in air revealed their stability to be up to 500 °C. This is comparable with commercial multi‐wall carbon nanotubes, which have similar areas of application. The nitrogen‐containing carbons are potentially useful as supports for catalysts and in applications where carbon of higher hydrophilicity would be of benefit. Copyright © 2010 Society of Chemical Industry