Enhanced Thermal Conductivity of 5A Molecular Sieve with BNs Segregated Structures

5A molecular sieves have been widely used as adsorbents in cryogenic distillation for hydrogen isotope separation in fusion reactor engineering, but its low thermal conductivity is detrimental to the process stability. Improving the thermal conductivity of 5A molecular sieves is one of the most important goals for high‐performance devices. Here, firm segregated structures with boron nitride sheets (BNs) are constructed around 5A molecular sieve particles. SEM results show 30 µm BNs tend to form the better networks in comparison with that of 0.12 µm BNs at 40 wt% loadings. It is further verified that BNs with the larger size promote the thermal conductivity. Meanwhile, the thermal conductivity increases with the increasing amounts of BNs. XRD and specific surface area results indicate that the sintering and the addition of BNs exert negligible effects on the structure of 5A molecular sieve. These results indirectly show 5A molecular sieve with BNs segregated structures is very likely to be used for the application of hydrogen isotopic separation. Besides, this work provides new insight into the construction of segregated structure in inorganic porous materials.

     

基于完全平方数的RSA密码分析算法机理

给出基于完全平方数的RSA密码分析算法的机理,分析满足同余式x2≡y2 (mod n)的完全平方数x和y的数域选择与算法效率的关系。通过数学证明和相关分析方法,定义RSA公钥n的素因子特征c,证明当c>2时,如果数域范围选择和构造的算法得当,则分解n的效率较高,当c<2时,使算法的运算数域增大,可以降低分解n的效率和有效性,即构造的RSA密码是安全的。     

杂原子分子筛ZrBSiALPO4-5的合成结构及催化性能的研究

我们用水热合成法合成了一种锆 -硼 -硅磷铝分子筛 ,通过化学分析、测定晶胞参数及用XRD ,MASNMR方法进行表征 ,证实了锆 -硼 -硅原子进入了分子筛骨架 ,并且具有和AlPO4- 5相似的结构 ;用IR ,NH3 -TPD表征方法测出了它们的酸性 ,测定结果表明 ,它具有L -酸和B -酸中心 ,以中等强度酸为主 ,在苯与烯烃烷基化反应中表现出良好的催化活性和长寿命并且对 2 -位和 3-位苯的烷基化反应具有高选择性 ,有可能替代HF成为一种环境友好的新型催化剂     

金属酞菁负载分子筛对孔雀石绿的降解

采用浸渍法制备了4种负载型金属酞菁催化剂：MCM-41-a-（GH11O）4PeCo（Ⅱ）[Ni（Ⅱ）、Cu（Ⅱ）、Zn（Ⅱ）]。并在室温（25±1℃）中性以及可见光条件下,考察了上述催化剂中心金属、催化剂用量、H2O2浓度以及重复利用方面对孔雀石绿降解速率的影响。研究结果表明：4种催化剂均具有良好的催化性能,在相同条件下,MCM-41-a-（C3H11O）4PcCo的催化效果最好,并且其浓度在0．7g／L（质量为20mg）,H2O2浓度为10mmol／L条件下,孔雀石绿在10min内降解率可达92％。对重复性的研究表明该种负载催化剂具有良好的重复利用性。     

Evaluation of metal-doped manganese oxide octahedral molecular sieves in catalytic reduction of NOx from cigarette mainstream smoke

A series of Ag, Cu and Co-doped manganese oxide octahedral molecular sieves (OMS-2) were synthesized and evaluated to remove nitrogen oxides (NO _x ) from cigarette mainstream smoke. The three kinds of catalysts were added to cigarettes for studying the capabilities of reducing NO _x from cigarette mainstream smoke. The catalysis and reduction of NO in laboratory were studied. A mechanism for NO _x catalytic reduction from burning cigarettes with the catalysts adding to cigarettes was described. The catalysts show excellent catalytic activity for NO _x removal, especially the Ag-doped OMS-2 catalyst. 0.5% (mass fraction) Ag-doped OMS-2 catalyst has the best ability to remove NO _x from cigarette mainstream smoke. The use of Ag-doped OMS-2 as catalyst for removing carcinogenic compounds from cigarette smoke will be an effective strategy to protect the environment and public health.     

微波辐射条件下SAPO-5分子筛的合成与表征

以异丙醇铝、磷酸、正硅酸乙酯为反应原料,三乙胺作为模版剂,功率800 W、180℃微波辐射30min合成了粒径均一、具有AFI拓扑结构的SAPO-5分子筛,系统研究了Al2O3与SiO2摩尔比和HF添加量等因素对产物长径比和晶体形貌的影响。采用XRD、SEM等分析手段对产物进行表征。结果表明,n(Al2O3)/n(SiO2)可以控制晶体尺寸的大小以及长径比,HF的存在影响晶体的成核及分散性。     

气相法制备沸石分子筛的研究进展

综述了气相法,包括气相转移法和干胶法在合成沸石分子筛、磷铝分子筛和其它杂原子分子筛及分子筛膜方面的研究进展。介绍了合成过程中一些影响因素,如时间、温度、干胶组分或有机模板剂对合成的影响。并且对气相法制备分子筛成型体作了简单介绍。     

空冷塔堵塞导致分子筛带水的原因及处理

KDN-6000型空分设备运行中因空冷塔塔板被脏物堵塞,发生分子筛纯化系统带水故障;采取相应的处理措施维持空分设备的运行;按计划停运空分设备后,清洗空冷塔,彻底排除故障。     

分子筛吸附器进水故障及其处理过程

KDONAr-10000／22000／370型空分设备因空冷塔液位计失效而发生分子筛吸附器进水故障。介绍了故障发生的经过和处理过程；最后得出了发现及处理分子筛吸附器进水故障的经验和教训。     

介孔分子筛MOM-41的合成及其孔径的调节

以十六烷基三甲基溴化铵为表面活性剂，正硅酸乙酯为硅源在酸性条件下合成具有完好六方结构的介孔分子筛MCM-41；利用1，3，5-三甲基苯（TMB）作为辅助剂对介孔分子筛MCM-41的孔径进行调节．结果表明：酸性条件下能够合成结构完善的介孔分子筛并且利用XRD、扫描电镜对其进行详细的表征，有代表完好六方结构的特征峰及孔道的存在；此外，1，3，5-三甲基苯（TMB）可以有效增大分子筛的孔径，并且通过N2吸附-脱附对其孔径的大小进行详细表征。