流动试验中酸碱性及电导率测试装置

文章介绍了流动试验中酸碱性及电导率测试装置设计原理及在试验过程中的应用。该装置最大的优点是能测量试验过程的瞬时值 ,还可以设定时间测量 ,适当改进后可以测试液体的瞬时离子浓度。该装置成本低 ,易安装 ,是一种提高工效 ,减轻劳动强度的实用性装置     

浅析立德粉ZnO含量超标原因

就生产中B30 1立德粉出现氧化锌含量超标现象 ,分析了实际生产过程、影响因素及生产数据 ,论证了问题产生的原因 ,指出立德粉中氧化锌含量超标与合成过程的pH值有关。     

米波雷达副瓣对消系统的设计

从雷达总体设计的角度，介绍了米波雷达副瓣对消技术在工程设计中的要点和注意事项，并根据所用的具体处理方法，进行了计算机仿真和试验，给出了仿真结果和试验结果，进行了比较。     

pH值对锌盐沉积的影响及其稳定剂的筛选评价

在碱性循环水处理中，锌盐是一种常用的缓蚀预膜剂，单独使用受pH值影响较大，容易发生沉积。研究结果表明，通过蒸发浓缩，当浓缩倍数达到2．5倍时，试验用水可以得到一个与生产现场相似的稳定的高pH值，在此条件下筛选出ZS－202是一种经济适用的锌盐稳定剂。     

The correspondence between susceptibility to SCC of brass and corrosion-induced tensile stress with various pH values

Corrosion-induced stress and susceptibility to stress corrosion cracking (SCC) of brass in an ammonia solution with various pH values have been studied. pH value dependence of corrosion-induced stress measured by two different methods showed a good agreement, and was correspondent to that of susceptibility to SCC. When pH?8, with increasing pH value, the corrosion-induced tensile stress had a maximum value and hardly changed; at the same time, the susceptibility to SCC exhibited a maximal value and a slight change. However, when pH?6, with decreasing pH value, both the corrosion-induced tensile stress and the susceptibility to SCC reduced rapidly. So, the SCC of brass in an ammonia solution was in close relationship with the corrosion-induced stress.     

Swelling behavior of pH‐ and temperature‐sensitive copolymers containing 2‐hydroxy‐ethyl methacrylate and N‐vinyl‐2‐pyrrolidone crosslinked with new crosslinkers

Copolymers of 2‐hydroxyethyl methacrylate (HEMA) and N‐vinyl‐2‐pyrrolidone (VP) and homopolymers of HEMA and VP were crosslinked in the presence of different mol% of melamine trimethacrylamide (MMAm) and melamine triacrylamide (MAAm) as crosslinkers by bulk radical polymerization. The resultant xerogels were characterized by extracting the soluble fractions and measuring the equilibrium water content. Lower critical solution transition temperatures (LCST) were measured by DSC. The properties of crosslinked HEMA and VP copolymers, VP and HEMA series were evaluated in terms of compositional drift of polymerization, heterogeneous crosslinking, and chemical structure of the relevant components. Soluble fractions of the crosslinked networks were reduced by varying the MAAm and MMAm concentrations. The influence of environmental conditions such as temperature and pH on the swelling behavior of these polymeric gels was investigated. The swelling behaviors of the resulting gels show pH sensitivity. This behavior is explained on the basis that amide groups of VP or crosslinkers could be hydrolyzed to form negatively charged carboxylate ion groups in the produced networks in response to an external pH variation. Copyright © 2004 Society of Chemical Industry     

The spatial distribution of Zn during galvanic corrosion of a Zn/steel couple

The spatial distribution of Zn²⁺ during galvanic corrosion of a model Zn/steel couple in 0.01 M NaCl was investigated using a scanning zinc disk electrode. The couple had a coplanar arrangement of a steel substrate with an electroplated zinc layer at the center. During galvanic corrosion, the marked changes in the Zn²⁺ concentration were confined to a thin solution layer ca. 1.0 mm thick above the couple surface. In this thin solution layer above the zinc layer, a higher concentration region of Zn²⁺ in the range of 5-18 mM extended around the zinc layer in the solution during galvanic corrosion. Conversely, above the steel surface distant from the zinc layer, the surface concentration of Zn²⁺ was almost zero during galvanic corrosion. On this surface, the precipitation of zinc corrosion products due to the hydrolysis reaction of Zn²⁺ was observed. The distribution of the Zn²⁺ concentration supported that Zn²⁺ acted as a buffer that suppressed the increased pH due to the cathodic reaction on the steel surface near the zinc layer and almost no corrosion products formed there. The spatial distribution of Zn²⁺ is discussed in relation to the distributions of potential and pH and the surface morphology of the galvanic couple.     

应用条形码开发煤气表管理信息系统

通过应用条形码技术结合燃气销售公司对煤气表具的实际管理需求．设计并实现了实用的煤气表管理信息系统。文章从系统的需求分析，条形码的应用角度说明了系统的设计与实现．最后探讨了开发该系统的发展前景。     

高压锅炉供水除氧防腐蚀剂XC-1

所报道的除氧防腐蚀剂XC－1，可用于压力6．5MPa以上，不能使用亚硫酸钠的蒸汽锅炉除氧，它以亚硫酸铵为主剂，复配以挥发性胺，成膜性胺，乳化剂等助剂，可迅速除氧并调节供水和蒸汽的pH值，防止高温腐蚀，探讨了亚硫酸铵的除氧机理及两种胺的作用，在内考察了不同加量的XC－1对胜利现河3号锅炉注汽转化水的除氧率（煮沸10分钟），加量27mg/L时除氧率98％，加量30mg/L时除氧率100％，在现河3号锅炉上进行了连续96小时的现场试验，XC-1在热力除氧器换热器前加入，除氧温度104℃，每8h加药一次，加药量由25mg/L增加到30mg/L当加量为27mg/L时锅炉供水含氧量在0．1mg/L以下，考虑到除氧温度，压力可能波动，加量确定为28mg/L，这时供水含氧量0．003－0．004mg/L，过剩SO3^2-含量在1．6－3．6mg/L范围，锅炉进口供水pH值平均为8．4,出口湿蒸汽pH值平均为10．03，PH值达到了要求。     

Aqueous Dispersion and Slip Casting of Boron Carbide Powder: Effect of pH and Oxygen Content

The effect of pH and oxygen content on the zeta potential, viscosity, and casting performance of fine (>3 μm) boron carbide powder is presented. X-ray photoelectron spectroscopy of the powder revealed a surface layer of adsorbed water and oxides of boron and carbon. The soluble boric acid impurity was removed by washing the powder with water or alcohols. Electrophoresis indicated that the B₄C surface was negatively charged in water above pH 1, but the presence of dissolved boric acid suppressed the zeta potential at high pH. Stable, low-viscosity dispersions of >30 vol% solids were prepared and slip cast at pH >6, but boric acid was destabilizing for dispersions prepared above pH 7. The green density of slip-cast parts was more reproducible and about 3% to 5% higher for washed powders than for high-oxygen-content powders.