硝酸羟胺的热稳定性评估及热分解机理研究

为评估氧化剂硝酸羟胺的热稳定性,使用标准液体铝皿于3K/min、4K/min、5K/min加热速率下进行热分析。借助非等温DSC曲线的参数值,应用Kissinger法和Ozawa法求得热分解反应的表观活化能和指前因子,根据Zhang-Hu-Xie-Li公式、Hu-Yang-Liang-Xie公式、Hu-Zhao-Gao公式以及Zhao-Hu-Gao公式,计算硝酸羟胺的自加速分解温度和热爆炸临界温度,并对热分解机理函数进行了研究。设计了7条热分解反应路径,采用密度泛函理论B3LYP/6-311++G(d,p)方法对硝酸羟胺的热分解进行了动力学和热力学计算。计算结果表明,硝酸羟胺热分解的自加速分解温度TSADT=370.05K,热爆炸临界温度Tbe0=388.68K,Tbp0=397.54K,热分解最可几机理函数的微分形式为f(α)=17×(1-α)18/17。硝酸羟胺热分解各路径中,动力学优先支持路径Path 6、Path 5、Path 4和Path 1生成NO和NO_2,其次是Path 2、Path 7和Path 3生成N2和N_2O。温度在373K以下时,Path 1′反应无法自发进行,硝酸羟胺无法进行自发的热分解。从热力学的角度来看,硝酸羟胺在370.05K以下储存是安全的。     

Electrochemical Behavior of Single CuO Nanoparticles: Implications for the Assessment of their Environmental Fate

The electrochemical behavior of copper oxide nanoparticles is investigated at both the single particle and at the ensemble level in neutral aqueous solutions through the electrode‐particle collision method and cyclic voltammetry, respectively. The influence of Cl^? and NO₃^? anions on the electrochemical processes occurring at the nanoparticles is further evaluated. The electroactivity of CuO nanoparticles is found to differ between the two types of experiments. At the single‐particle scale, the reduction of the CuO nanoparticles proceeds to a higher extent in the presence of chloride ion than of nitrate ion containing solutions. However, at the multiparticle scale the CuO reduction proceeds to the same extent regardless of the type of anions present in solution. The implications for assessing realistically the environmental fate and therefore the toxicity of metal‐based nanoparticles in general, and copper‐based nanoparticles in particular, are discussed.     

在盐湖地区暴露48个月纯锌的腐蚀行为

采用X射线衍射(XRD)、扫描电子显微镜(SEM)、金相显微镜和电化学阻抗等手段研究了锌在青海盐湖大气环境(富盐干旱型大气环境)中的腐蚀行为。结果表明,在青海盐湖大气环境中锌的腐蚀规律遵循经验公式m=Atn。锌的向地面比向天面腐蚀严重,向天面暴晒48个月出现锈层脱落现象。两个表面的腐蚀产物均由Zn5(OH)8Cl2·H2O,Zn5(CO)3(OH)6和Zn4SO4(OH)6·3H2O组成,锈层均富含SiO2。电化学结果表明,随着暴晒时间的延长向地面的极化电阻Rp逐渐增大,而向天面的Rp逐渐增加,而暴晒48个月时减小。锈层有抑制基体腐蚀的作用,对两个表面锈层的保护性随暴晒时间的延长而增大,而向天面暴晒48个月时保护性减弱。     

察尔汗盐湖资源与我国钾肥工业发展

概述了察尔汗盐湖的自然条件、地质条件与资源状况,阐明了我国钾肥工业的现状以及察尔汗盐湖资源开发对发展我国钾肥工业的重要作用。     

硝酸铈铵在有机合成中的应用

就近１０年来硝酸铈铵在硝化及硝酸酯化,氧化和催化氧化,引发加成和聚合等方面进行的应用进行了综述。     

基于PLC的变频节能系统在井筒冻结施工中应用的研究

针对冻结施工法装机容量大、电能消耗高以及施工过程的阶段性特点,在分析了冻结系统螺杆盐水机组不同工况下的机械特性和在各个冻结阶段电能消耗情况下,设计了一种基于PLC的变频节能系统。该系统以PLC为控制核心,通过压力传感器、液位计等对系统工况信息进行反馈,利用PID算法控制变频器的输出频率,从而达到了调节盐水泵流量、控制供冷量的目的。实验数据论证了该系统在井筒施工中应用的可行性与高效性。     

基于OpenCL的MD5破解算法

在基于GPU的异构平台上,采用开放计算语言(OpenCL)实现破解算法,利用分轮生成攻击密码、图形渲染管线加速存取以及多密码并行等方法对算法进行优化,在Intel四核CPU Q8230(2.3 GHz)和一片NVIDIA GT200组成的平台上进行实验。实验结果表明,在相同CPU平台上该算法能够获得高于破解软件John the ripper 17倍的破解速度。     

Fabrication and gas-sensing properties of hierarchically porous ZnO architectures

Hierarchically three-dimensional (3D) porous ZnO architectures are synthesized by a template-free, economical aqueous solution method combined with subsequent calcination. First, the precursors of interlaced and monodisperse basic zinc nitrate (BZN) nanosheets are prepared. Then calcination of the precursors produces hierarchically 3D porous ZnO architectures composed of interlaced ZnO nanosheets with high porosity resulting from the thermal decomposition of the precursors. The products are characterized by X-ray diffraction, thermogravimetric-differential thermalgravimetric analysis, scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller N₂ adsorption-desorption analyses. The BET surface area of the hierarchically porous ZnO nanostructures was calculated to be 12.8 m² g⁻¹. Compared with ZnO rods, the as-prepared porous ZnO nanosheets exhibit a good response and reversibility to some organic gases, such as ethanol and acetone. The responses to 100 ppm ethanol and acetone are 24.3 and 31.6, respectively, at a working temperature of 320 °C. These results show that the porous ZnO architectures are highly promising for gas sensor applications, as the gas diffusion and mass transportation in sensing materials are significantly enhanced by their unique structures. Moreover, it is believed that this solution-based approach can be extended to fabricate other porous metal oxide materials with a unique morphology or shape.     

氧化氮压缩机铵盐的清除

分析了硝酸生产过程中铵盐形成的原因和对氧化氮压缩机的危害，对喷水、喷蒸汽2种清除铵盐的方法进行了分析比较．     

钡盐产品的研究开发和展望

介绍了国内外主要钡盐产品的研究开发现状和生产状况 ,并且阐述了主要的钡盐产品的应用前景和市场动态趋势