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51.
锂离子交换ZSM-5型分子筛中水分子吸附特性的分子模拟 总被引:1,自引:0,他引:1
用巨正则系综Monte Carlo(grand canonical assemblage Monte Carlo,GCMC)模拟方法计算了水在HZSM-5型分子筛中的吸附热,计算结果与文献报道的实验结果吻合得较好.模拟了水在经锂离子(Li )交换后的ZSM-5型分子筛上的吸附等温线.在此基础上,进一步预测了水在不同硅铝摩尔(下同)比的LinZSM-5型分子筛中的吸附性质.计算结果显示:分子筛骨架上的硅铝比显著影响水的吸附量和等温吸附曲线,随着硅铝比的减小,分子筛中的自由体积减小,对水的吸附量增加.水分子的主要吸附位置是在Li 和铝原子的周围,LinZSM-5型分子筛中存在着1个主要的吸附位点.Li 等金属阳离子的交换能有效降低水的吸附热.在吸附量相同的条件下,水的吸附热随着硅铝比的升高而降低. 相似文献
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Daniela T?uber Christian von Borczyskowski 《International journal of molecular sciences》2013,14(10):19506-19525
Single molecule (SM) methods are able to resolve structure related dynamics of guest molecules in liquid crystals (LC). Highly diluted small dye molecules on the one hand explore structure formation and LC dynamics, on the other hand they report about a distortion caused by the guest molecules. The anisotropic structure of LC materials is used to retrieve specific conformation related properties of larger guest molecules like conjugated polymers. This in particular sheds light on organization mechanisms within biological cells, where large molecules are found in nematic LC surroundings. This review gives a short overview related to the application of highly sensitive SM detection schemes in LC. 相似文献
55.
分析了液体精密过滤技术存在的问题,介绍了新型高分子微孔精密过滤技术的特点以及过滤工程的基本设计计算;通过工程实例,论述了精密澄清技术在合成氨净化系统的应用。 相似文献
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Effects of the particle-particle heat transfer in a gas-solid turbulent flow in a riser were evaluated. An Eulerian/Lagrangian four-way interaction formulation including the particle collisions in conjunction with the k − τ and the kθ − τθ model equations were used in the numerical simulation. Inter-particles and particle-wall interactions were accounted for with an inelastic collision model, where the restitution coefficient was evaluated for each collision. The special case when the flow initially contains two groups of hot and cold particles was treated in details. Particular attention was given to the nature of heat transfer to particles due to inter-particle interactions. The results showed that the effect of particle-particle heat transfer was more significant for smaller sizes, lower flow Reynolds numbers, and for higher loading ratios. Solid thermal properties, however, did not have a noticeable effect on the inter-particle heat transfer. The simulation results indicates that although the heat transferred to each group of hot and cold particles was significant, the mean values of gas and particle temperatures and suspension heat transfer was insensitive to the inter-particle heat transfer. 相似文献
57.
目的为了拓宽聚环氧琥珀酸(PESA)的应用范围,合成了衣康酸改性聚环氧琥珀酸衍生物(IA-PESA),拟提高PESA的阻垢缓蚀性能。方法用顺酐合成环氧琥珀酸(ESA)和聚环氧琥珀酸(PESA),再利用ESA与衣康酸(IA)聚合制得IA-PESA,研究了IA-PESA的阻垢和缓蚀等综合性能。用FT-IR对PESA和IA-PESA进行表征。用黏度法测定了PESA和IA-PESA的分子量。结果在静态阻垢实验中,对CaCO_3阻垢率达到90%以上,对CaSO_4阻垢率高达95%,甚至100%。IA-PESA分散Fe(Ⅲ)和稳定Zn~(2+)性能明显好于PESA。在静态失重实验中,当IA-PESA与PESA的用量均为150 mg/L时,加IA-PESA的腐蚀速率明显小于加PESA的腐蚀速率。对钙垢和腐蚀试片的SEM研究表明,IA-PESA使致密度较高、晶格结构规整的CaCO_3和CaSO_4钙垢改变为致密度较低、疏松、形状不规整的晶型结构。IA-PESA使试片未发生均匀腐蚀和点蚀,表面光滑。结论在相同测试条件下,IA-PESA的阻垢、缓蚀、分散Fe(Ⅲ)和稳定锌性能都好于PESA,改变了设备表面钙垢的晶型结构,减少了垢下腐蚀,缓蚀作用明显。 相似文献
58.
Measurements of thermal conduction in tokamaks parallel to the magnetic field were up to 20 times less than the classical
values. This was explained by the quantum correction of the collision frequency of electrons with ions. This stowing effect
of heat is applied to re-evaluate the ignition threshold for the energy flux density E* for the ignition of solid state density
deuterium tritium using nonlinear (ponderomotive) laser force driven space charge neutral plasma blocks. 相似文献
59.
应用微观粒子波动和分子轨道理论,解释生物标志化合物在沉积体系中自身独有的“电子离域-外质子磁旋反应”的重排机理。首先阐明生物标志化合物立体异构重排的理论依据;然后分别探讨了萜、甾烷类立体异构重排和成熟度对应关系;极性、非极性生物标志化合物异构体重排和油气运移对应关系。 相似文献
60.
Yaxin Wang Binghong Xu Sen Ma Hao Wang Luqing Shang Cheng Zhu Sheng Ye 《International journal of molecular sciences》2022,23(4)
As the etiological agent for the coronavirus disease 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenges the ongoing efforts of vaccine development and drug design. Due to the accumulating cases of breakthrough infections, there are urgent needs for broad-spectrum antiviral medicines. Here, we designed and examined five new tetrapeptidomimetic anti-SARS-CoV-2 inhibitors targeting the 3C-Like protease (3CLPro), which is highly conserved among coronaviruses and essential for viral replications. We significantly improved the efficacy of a ketoamide lead compound based on high-resolution co-crystal structures, all-atom simulations, and binding energy calculations. The inhibitors successfully engaged the catalytic dyad histidine residue (H41) of 3CLPro as designed, and they exhibited nanomolar inhibitory capacity as well as mitigated the viral loads of SARS-CoV-2 in cellular assays. As a widely applicable design principle, our results revealed that the potencies of 3CLPro-specific drug candidates were determined by the interplay between 3CLPro H41 residue and the peptidomimetic inhibitors. 相似文献