关于PN空间上线性算子的概率范数

本文提出PN空间上线性算子的概率范数的新定义,并用它对算子有界性进行刻划,还讨论了算子空间的完备性.     

Numerical research on the coherent structure in the viscoelastic second-order mixing layers

I.IntroductionViscoelastict'olwsareprevalentinstiring,mixingandchemicalreactionofdilutepolymersolutions.SinceTomsdiscoveredthedragreducingeffectofpolylllerudditivesontul.bulent11owsin1948,1llilnystudiesonitsmechanisms11acebeendoneinviewofitsenormouspr'tcticillalld[lleorcticill\'al[Ics.UPtodata,1ilorcasonilbicilltcrl,rclilti')lls,II()wcvcr,ill'cstillun'lvtlilabjedLlctotiledilllcultiesillfoeviscoelasticdyllalnicsalldthetLlrbulellcetllcory.Al'cwpolymericadditiveshavinglittleeffectonthesolvent…     

高效液相色谱法测定大鼠肺及脑组织中细胞膜磷脂

A successful method for separation and quantitative determination of phosphatidylinositol(PI),phos-phatidylserine(PS),phosphatidylethanolanune(PE)and phosphatidylcholine(PC) in membrane of rat lungand brain tissues by HPLC has been developed.Under the selected conditions ,the averagerecoveries of themwere 84.14～88.43%, The contents of PI, PS, PE and PC(mean±SD)per gram of tissues in the mem-brane of normal rat lung were 201.1±20.8μg,350.6±20.0μg,162.0±11. 6μg and 24.66±2.04mg respec-tively.     

On the possible reaction pathway for the acylation of AChE-catalyzed hydrolysis of ACh: Semiempirical quantum chemical study

The acylation process in the acetylcholinesterase (AChE)-catalyzed hydrolysis of the neurotransmitter, acetylcholine (ACh), has been determined with the semiempirical quantum chemical calculation method AM1 using the model molecules extracted from the X-ray crystal structure of Torpedo Californica AChE. For the sake of identifying the microfeatures of the mechanism of this reaction, two types of possible mechanisms, stepwise mechanism and cooperative mechanisms, were proposed and studied with AM1 methods. All the model molecules for the possible reactants, intermediates, transition states, and products in the reaction pathways of the two mechanisms were obtained. Energy profiles, the structural properties of the transition states, indicate that the acylation of AChE-catalyzed hydrolysis of ACh adopts the cooperative mechanism, i.e., the proton transfer from Ser220 of AChE to His440 occurs simultaneously with the nucleophilic attack of Ser200 to the carbonyl carbon atom of ACh. This result is in agreement with the kinetic data and the secondary isotope effects of AChE-catalyzed reactions. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 515–525, 1998     

Unraveling the Oxidation Behaviors of MXenes in Aqueous Systems by Active-Learning-Potential Molecular-Dynamics Simulation

MXenes are 2D materials with great potential in various applications. However, the degradation of MXenes in humid environments has become a main obstacle in their practical use. Here we combine deep neural networks and an active learning scheme to develop a neural network potential (NNP) for aqueous MXene systems with ab initio precision but low cost. The oxidation behaviors of super large aqueous MXene systems are investigated systematically at nanosecond timescales for the first time. The oxidation process of MXenes is clearly displayed at the atomic level. Free protons and oxides greatly inhibit subsequent oxidation reactions, leading to the degree of oxidation of MXenes to exponentially decay with time, which is consistent with the oxidation rate of MXenes measured experimentally. Importantly, this computational study represents the first exploration of the kinetic process of oxidation of super-sized aqueous MXene systems. It opens a promising avenue for the future development of effective protection strategies aimed at controlling the stability of MXenes.     

An important biodegradable polymer – polylactone-family polymer

Systemic investigation on the synthesis and properties of aliphatic polylactones were carried out. And various materials were obtained with different degradation rates and mechanical properties. Two in vivo experiments were presented in this study to envision the biomedical applications of this kind of aliphatic polylactones.