NMR investigation of guest–host complex between chloroform and cryptophane C

Guest–host complex between cryptophane C, possessing two non‐equivalent caps, and chloroform is investigated by NMR spectroscopy. The kinetics of the chloroform exchange between the bound and free sites is determined by ¹H exchange spectroscopy. Moreover, the preferential orientation of chloroform molecule with respect to the cryptophane C frame is examined by the NOESY and ROESY experiments. The experimental findings are compared to the results of quantum chemical calculations. Copyright © 2010 John Wiley & Sons, Ltd.     

Proceedings of the third European Seminar on Mathematics in Engineering Education held at Politecnico di Torino,Italy, 19‐22 March 1986

In this presentation, we attempt further investigation into the interval of uncertainty #opI _u#cp on the particular integral for a geophysical problem of the form:

subject to the regularity condition at the poles given by

Using knowledge of optimization problems of the one‐dimensional search type, we desire to establish the notion that the interval of uncertainty to the particular integral fits into the regularity condition as stated above. Our choice of method falls on the dichotomous search technique, the algorithmic procedure of which rapidly reduces the length of I _u. This then paves the way for the certification of the stability of our solution scheme.     

(E)‐,(Z)‐Parallel Preparative Methods for Stereodefined β,β‐Diaryl‐ and α,β‐Diaryl‐α,β‐unsaturated Esters: Application to the Stereocomplementary Concise Synthesis of Zimelidine

Parallel and practical methods for the preparation of both (E)‐ and (Z)‐β‐aryl¹‐β‐aryl²‐α,β‐unsaturated esters 1 and (E)‐ and (Z)‐α‐aryl¹‐β‐aryl²‐α,β‐unsaturated esters 2 are described. These methods involve accessible, robust, stereocomplementary N‐methylimidazole (NMI)‐mediated enol tosylations (14 examples, 70–99 % yield), as well as stereoretentive Suzuki–Miyaura cross‐couplings (36 examples, 64–99 % yield). The highlighted feature of the present protocol is the use of parallel and stereocomplementary approaches to obtain highly (E)‐ and (Z)‐pure products 1 and 2 by utilizing sequential enol tosylations and cross‐coupling reactions. An expeditious and parallel synthesis of (E)‐ and (Z)‐zimelidine ( 3 ), which is a highly representative selective serotonin reuptake inhibitor (SSRI), was performed by utilizing the present methods.     

The Panel Method for Rigid Section Group Added Mass Coefficients and Its Application to Fuel Assemblies北大核心CSCD

A numerical method based on the panel method was developed to calculate the added fluid mass coefficients of the rigid section group with arbitrarily complex shapes, and was successfully applied to the PWR fuel assemblies. The variation law of added mass coefficients with position deviations was analyzed in the seismic test of 1×5 fuel assemblies. The results show that, this method is suitable for the calculation of the added mass coefficients of rigid section groups with complex continuous boundaries. Compared with the gap between assemblies, the gap between baffles and assemblies has a dominant influence on the added mass coefficient. Regardless of the position deviation, the sum of the added mass coefficients of all assemblies and baffles in the assumed motion direction is approximately equal to –1, and that in the perpendicular direction is approximately equal to 0. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

激发态Li原子和基态Ar原子的相互作用势及低能弹性碰撞

在MRCI+Q/ang-cc-PCVQZ+DK理论基础上对LiAr第一激发态(A²Π)的势能曲线进行了理论计算, 采用HFD(Hartree-Fock dispersion)解析势能函数对得到的势能曲线进行拟合, 并得到了相应的光谱常数, 计算结果与实验值和大部分理论计算值符合得很好. 通过求解核运动的薛定谔方程完整地获得了每个电子态下J=0时的振动能级E_v、转动惯量B_v和6 个离心畸变常数(D_v, H_v, L_v, M_v, N_v, O_v). 然后采用分波法研究了低温及极低温度下激发态Li原子和基态Ar原子沿LiAr相互作用势的弹性碰撞, 在1.0×10^{- 12} –3.45×10^-6 eV碰撞能区内通过数值计算得到了这一弹性碰撞的总截面和各分波截面, 讨论了各分波截面对总截面的影响. 结果表明: 在入射能量低于10^-9 eV时弹性散射的总截面值很大且几乎为一常数, 总弹性截面的形状主要由s分波决定, 但是随着碰撞能量的增加, s分波对总截面的贡献不断减少, 高阶分波对散射截面的贡献逐渐增大.     

Lifting Galois sections along torsors

The cuspidalization conjecture, which is a consequence of Grothendieck's section conjecture, asserts that for any smooth hyperbolic curve X over a finitely generated field k of characteristic 0 and any non empty Zariski open , every section of lifts to a section of . We consider in this article the problem of lifting Galois sections to the intermediate quotient introduced by Mochizuki 10 . We show that when and is an union of torsion sub‐packets every Galois section actually lifts to . One of the main tools in the proof is the construction of torus torsors and over X and the geometric interpretation .     

中高能入射条件下裸碳离子碰撞氦原子单电离的全微分截面

利用四体模型计算了100 和 2 MeV/amu裸碳单电离氦原子的全微分截面,其结果与实验数据和其它理论进行了比较。对于高能入射情况,在散射平面小动量转移和中间动量转移时现在的理论结果和实验符合的很好,然而在大动量转移时和在垂直平面有明显差异。对于低能入射情况,四体结果定性与实验结果一致,而且优于三体扭曲波(3DW-EIS)结果,表明四体效应在低能入射比在高能入射时明显。     

CO2‐Breathing Induced Reversible Activation of Mechanophore within Microgels

In this work, CO₂‐breathing induced reversible activation of mechanophore within microgels is reported. The microgels are prepared through soap‐free emulsion polymerization of CO₂‐switchable monomer 2‐(diethylamino)ethyl‐methacrylate, using spiropyran (SP) based mechanophore MA‐SP‐MA as cross‐linker. The microgels can be swollen by CO₂ aeration. The swelling of microgels activates the SP mechanophore into merocyanine, causing distinguished color and fluorescence change. Moreover, these transitions are highly reversible, and the initial states of microgels can be easily recovered by “washing off” CO₂ with N₂. The present contribution represents the first example of CO₂‐breathing activation of mechanophore within microgels.

     

半圆环截面细环壳的屈曲

本文由Sanders非线性平衡方程和Koiter小应变协调方程推导出细环壳的非线性微分方程和稳定方程。用伽辽金法求解了静水压或边界载荷作用下的半园环截面细环壳的稳定方程。对于不同的边界条件及一系列几何参数,计算得到了临界载荷及屈曲模态。     

浅悬链线壳的轴对称问题

本文得到了中心无孔口和有孔口的浅悬链线壳的一般解答,并给出了有关算例.