查询词典 sieve analysis

The Si/Al ratio of NaY molecular sieve was determined by an empirical formula of lattice constant obtained by extension function method of X-ray diffraction and framework Si/Al ratio of NaY molecular sieve determined by solid nuclear magnetic resonant spectrum method.

前言晶胞参数是决定晶体结构的重要参数之一，Na Y超稳分子筛属立方晶系，由于 Na Y超稳分子筛骨架硅铝比受许多条件的影响，如投料比、晶化温度、晶化压力和晶化时间等。通过研究发现分子筛骨架的硅铝比与其晶胞参数相关，而分子筛的硅铝比可作为合成分子筛产品质量的控制指标 [1] 。

The present invention adopts the technical proposal of adopting ZSM-5 mesoporous molecular sieve raw powder with a silicon-aluminum mol ratio SiO2Al2O3 of 20 to 1000 and a weight percentage of 20 to 100 percent as well as at least one caking agent selected from SiO2, clay and Al2O3 to extrude, tablet or spray into shape; then treating for 1 to 8 hours by 0.1 to 3 mol/l of at least one ammonium liquor from ammonium nitrate, ammonium chloride or ammonium sulphate or 0.1 to 8.5 mol/l of at least one acid liquor from muriatic acid, nitric acid, vitriol or acetic acid under a temperature of 20 to 90 DEG C; then using steam to treat for 2 to 15 hours under the temperature condition of 400 to 700 DEG C; using a liquor of 0.1 to 3mol/l selected from at least one of oxalic acid, citric acid or maleic acid under a temperature condition of 20 to 90 DEG C to dip for 2 to 5 hours to obtain the modified molecular sieve catalyst, thus better solving the problems.

本发明通过采用硅铝比SiO2/Al2O3为20～1000重量百分比计20～100％的ZSM-5介孔分子筛原粉与余量的选自SiO2、粘土或Al2O3中至少一种粘结剂挤条、压片或喷球成型；再经过0.1～3摩尔/升选自硝酸铵、氯化铵或硫酸铵中的至少一种铵溶液或0.1～8.5摩尔/升选自盐酸、硝酸、硫酸或乙酸中的至少一种酸溶液在温度20～90℃下处理1～8小时；然后在温度为400～700℃条件下水蒸汽处理2～15小时；再用0.1～3摩尔/升选自草酸、柠檬酸或马来酸中至少一种在温度为20～90℃条件下浸渍2～5小时得所需改性分子筛催化剂的技术方案较好地解决了该问题，可用于甲醇转化制丙烯的工业生产中。

Based on maximum likelihood estimate, the estimate method of sieving rate of connectivity sieve was presented. Three key issues in the estimate were analyzed:calculation of sample size,generation of random sample, and recognition of connectivity of induced subgraph. By preassigned credibility and precision, effective estimate of sieving rate of connectivity sieve is achieved.

目前，产品拆卸过程规划基本上是建立在图的基础上，即首先根据产品拆卸回收或拆卸维修信息，选用一种适合的图模型进行描述，然后在图模型的基础上，以拆卸回收或拆卸维修的经济性、环境协调性和技术性等综合指标最优为目标，进行拆卸过程规划，最终得到产品的最优拆卸序列【1一。1连通性筛子拆卸与或图是拆卸模型中的一种，文献[7]给出了拆卸与或图的定义及建模过程。

The invention relates to an improved MCM-41 mesoporous molecular sieve and a preparation method thereof, in particular relates to a dual-metal-atom improved MCM-41 mesoporous molecular sieve and the preparation method thereof.

本发明涉及一种改性MCM-41介孔分子筛及其制备方法，特别是涉及一种双金属原子改性MCM-41介孔分子筛及其制备方法。

The gold particles were located at the edge of sieve plate pore between the two sieve elements.

位于筛分子质膜上的己糖载体蛋白的数量随果实发育进程明显增加。

Sieve net and its degrees are better than the wind through the metal sieve plate, well received by consumers.

其筛净度和透过度均优于风板铁皮筛，深受广大用户好评。

The lower sieve plate has the same or differnt sieve pore sizes.

所述的下筛分板是漏孔尺寸相同的筛分板或是漏孔尺寸不相同的筛分板。

A new relationship between pressure drop of the sieve plate column and velocity of flow was proposed in this paper. That the pressure drop of the sieve plate column wasn't proportion to the square of gaseous velocity.

提出计算板式塔塔板压降与气体流量的新关系，认为板式塔的压力降与气体通过筛孔的流动速度的平方不成正比。

Based on the theory of the structure dynamics, with the limited element SAP5 programm as the calculating way, a calculatingway of the dynamics intenisity of the sieve s lateral plate is put forward and the reason why this kind of oscillating sieve causes crcak on the lateral plate is analyzed.

以结构力学理论为依据，以有限元SAP5程序为计算手段，提出了一种直线振动筛侧板的动力学强度的计算方法，并分析了这类振动筛在侧板上产生裂纹的原因。

The good characteristic of polyurethane material makes the polyurethane sieve plate evidently exceed the rubber sieve plate in the application and processing.

由于聚氨酯材料优良的特性使得聚氨酯筛板在应用与加工方面明显优于橡胶筛板。

We are forbidden from giving money to these shoeless, skinny children, as this will perpetuate begging.

向光着脚，骨瘦如柴的孩子施舍是不可以的，因为要招来无休无止的乞讨。

It would be hard not to fall victim to some sharpeyed policeman.

要想不被某个目光锐利的警察抓到，谈何容易。