色谱法化学吸附仪在催化剂行业中的应用

正根据要求,可以使用脉冲法、连续流动法、迎头法,以及程序升温脱附技术,在一套设备上逐个测定催化剂的反应速度、金属分散性或其它活性中心、表面酸碱度和质量传递性能等,以便参照催化全过程的多种原位数据,有效地改进催化剂的活性、选择性及寿命。在多相催化中,由于反应体系的复杂性,使得再解释催化活性及其机理上遇到了困难,因而妨碍了对特定化学过程最佳催化剂的选择。在近代,虽然有着各种能谱,     

透射电子显微技术在RIPP炼油催化剂表征中的应用

利用透射电子显微技术对加氢催化剂以及积炭催化裂化催化剂进行了表征。扫描透射电子结合X射线能谱技术确定了氧化态加氢催化剂中的微粒为活性金属组分的适度聚集；能量过滤透射显微技术获得了积炭催化裂化催化剂的Al、C的元素分布像。     

测定Ni催化剂金属分散度的分析方法比较

分别采用动态脉冲H2化学吸附、静态H2化学吸附、H2-O2滴定法和H2-程序升温脱附(H2-TPD)法测定了Ni催化剂的金属分散度,探讨了不同测试方法、不同测试条件对金属分散度测定的影响。结果表明,动态脉冲H2化学吸附、静态H2化学吸附这两种测量方法比较适合Ni催化剂金属催化剂的测定,重复性较好。而H2-O2滴定法和H2-TPD法实验偏差相对较大,H2-O2滴定法只有在一定的测试条件进行才能保证测试结果的真实性。     

负载型金属催化剂原子级表征及研究进展

负载型金属催化剂具有选择性高、活性高、稳定性高、腐蚀性小、可重复利用的特点,这些性能与催化剂结构存在很大关系。基于对负载型金属催化剂结构和作用机理的深入研究,本文介绍了几种负载型金属催化剂的原子级表征技术。主要归纳了几种表征技术的适用范围、不同表征数据的分析。通过这些表征技术以及多种技术的融合使用,为最终实现催化剂的实际工业价值提供可能性。     

2800型化学吸附仪

2800型化学吸附仪是我国从美国Micromeritics仪器公司引进的第一台全自动化学吸附仪,该仪器可测定催化剂的金属分散度、表面积等表面性质,是催化剂研制与开发以及研究催化反应机理的有效测试手段。通常测定金属分散度是采用将合适的气体选择性化学吸附到活性组分表面上的化学吸附法。从实验技术上讲,化学吸附又分为容量法、重量法、色谱法等。2800型化学吸附仪,在样品预处理阶段采用流动法,在分析阶段采用静态容量法。仪器的主要特点是:自动化程度高;研究型软盘灵活性大;测试结果直观并     

车用天然气发动机Rh基三元催化系统的N_2O和NH_3生成特性研究

采用一维整体催化器模型和气固两相独立守恒方程,引入输运系数,建立了一种适用于天然气发动机的Rh基三元催化系统的整体多相催化反应机理,主要包括碳氢化合物CH_4的氧化反应和NO还原反应。采用程序升温方法研究了高温下N_2O和NH_3在模拟尾气中的生成特性,结果表明:NO浓度的降低和温度的升高会减少N_2O和NH_3的生成;CH_4浓度对NH_3排放影响不大,对N_2O的影响比较复杂;在700～930K范围内,CH_4浓度越高,N_2O生成越少;继续升温,CH_4浓度越高,N_2O生成越多。NO浓度对CH_4和CO起燃特性的影响很小,CH_4浓度对Rh基催化剂的CO氧化转化也没有影响,但是能促进NO的催化还原反应。尾气中的CH_4、NO浓度对N_2O的形成起着重要作用。     

热重-质谱法研究蓝色签字笔墨水的人为老化

采用热重-质谱联用（TDG-MS）技术研究纸张上蓝色签字笔墨水在人为老化过程中组分的变化情况。热重 质谱联用仪跟踪分析了签字笔墨水中易挥发物质离子流的成分以及它们随时间的变化。研究了纸张上多种常用蓝色签字笔的墨迹在程序升温加热条件下的人为老化,探讨总结了纸张载体上签字笔墨水在加热人为老化过程中的一些变化规律。该规律将为各种签字笔字迹相对书写时间检验鉴定方面的进一步研究提供科学依据。     

化学计量学用于裂化汽油样品PONA分析

用气相色谱以程序升温方式分析了裂化汽油,并将各组分程序升温保留时间转换为恒温保留指数.以各组分在OV-1和SE-54固定相上,同一柱温下的保留指数差及在各柱上的温度系数为三因素进行斜交因子分析和本征矢量旋转,给出了裂化汽油样品的PONA值,经色谱-质谱仪分析验证了结果的正确性,为裂化汽油样品的PONA分析提供了一种新方法.     

常压渣油在加氢预处理过程中组成变化的质谱研究

用正庚烷沉淀出沙中常压渣油中的沥青质 ,脱去沥青质后用氧化铝和硅胶的串联吸附色谱柱将其分离为饱和组分、芳香组分和胶质组分。采用高离子化电压质谱技术和场解析质谱技术分别对饱和组分、芳香组分和胶质组分进行分析 ,以研究常压渣油在加氢预处理过程中的组成变化 ,为渣油加氢催化剂的研制及工艺研究提供参考依据     

蔬菜中有机磷农药残留的检测方法

研究蔬菜中四种有机磷农药(敌敌畏、甲胺磷、毒死蜱、对硫磷)残留同时分析的方法。采用气相色谱氮磷检测器，在程序升温条件下不分流进样，根据保留时间确定样品组分。在所测定的含量范围内，含量与峰面积的相关系数均大于0．99，平均回收率在64．7％～91．8％之间。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.