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Degradation mechanism of 2,4,6-trinitrotoluene in supercritical water oxidation

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Journal of Environmental Sciences 2007年第12期19卷 1430-1435页

作者： chang Shuang-jun LIU yu-cun College of Chemical Engineering and Environment North University of China Taiyuan 030051 China

The 2,4,6-trinitrotoluene （TNT） is a potential carcinogens and TNT contaminated wastewater, which could not be effectively disposed with conventional treatments. The supercritical water oxidation （SCWO） to treat TNT contaminated wastewater was studied in this article, The TNT concentration in wastewater was measured by high-performance liquid chromatograph （HPLC） and the degraded intermediates were analyzed using GC-MS. The results showed that SCWO could degrade TNT efficiently in the presence of oxygen. The reaction temperature, pressure, residence time and oxygen excess were the main contributing factors in the process. The decomposition of TNT was accelerated as the temperature or residence time increased. At 550℃, 24 MPa, 120 s and oxygen excess 300%, TNT removal rate could exceed 99.9%. Partial oxidation occured in SCWO without oxygen. It was concluded that supercritical water was a good solvent and had excellent oxidation capability in the existence of oxygen. The main intermediates of TNT during SCWO included toluene, 1,3,5-trinitrobenzene, nitrophenol, naphthalene, fluorenone, dibutyl phthalate, alkanes and several dimers based on the intermediate analysis. Some side reactions, such as coupled reaction, hydrolysis reaction and isomerization reaction may take place simultaneously when TNT was oxidized by SCWO.

关键词： supercritical water oxidation TNT degradation mechanism wastewater treatment

Study on Dynamic Characteristics of Hydraulic Pumping Unit on Offshore Platform

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China Ocean Engineering 2017年第6期31卷 693-699页

作者： chang Zong-yu yu Yan-qun QI Yao-guang College of Engineering Ocean University of ChinaQingdao 266100China College of Mechanical and Electronic Engineering China University of PetroleumQingdao 266580China

A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit＇s hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.

关键词： offshore platform platform pumping unit kinematic model dynamic model multiple degrees of freedom

Hydrothermal Synthesis and Structure Analysis of Indium Vanadate (InVO_4)

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Chinese Journal of Structural Chemistry 2005年第11期24卷 1242-1248页

作者： HUANG Qing-Ming yu Jian-chang Instrumentation Analysis and Research Center Fuzhou University Fuzhou Fujian 350002 China Material science and engineering department Fuzhou University Fuzhou Fujian 350002 China

In this article, hydrothermal process is applied to synthesize nanometer InVO4. Influences of different experimental conditions （including mixing ratio of raw materials, reaction temperature, reaction time and so on） upon the synthetic products＇ purity and crystallite size are discussed to determine the best synthetic condition. The structure of nanometer InVO4 is analyzed, which helps to further understand the structure characteristics of InVO4 synthesized by applying hydrothermal process and lays foundation for further research.

关键词： hydrothermal process InVO4 experimental conditions structure

Is necrosectomy obsolete for infected necrotizing pancreatitis? Is a paradigm shift needed?

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World Journal of Gastroenterology 2014年第45期20卷 16925-16934页

作者： yu-Chung chang Department of Surgery Chung Shan Medical University Hospital College of Medicine Chung Shan Medical University

In 1886,Senn stated that removing necrotic pancreatic and peripancreatic tissue would benefit patients with severe acute *** then,necrosectomy has been a mainstay of surgical procedures for infected necrotizing pancreatitis(NP).No published report has successfully questioned the role of ***,however,increasing evidence shows good outcomes when treating walled-off necrotizing pancreatitis without a *** literature concerning NP published primarily after 2000 was reviewed;it demonstrates the feasibility of a paradigm *** majority(75%)of minimally invasive necrosectomies show higher completion rates:between 80%and 100%.Transluminal endoscopic necrosectomy has shown remarkable results when combined with percutaneous drainage or a metallic *** morbidities range from 40%to 92%.Single-digit mortality rates have been achieved with transluminal endoscopic necrosectomy,but not with video-assisted retroperitoneal necrosectomy *** procedures without necrosectomy have evolved from percutaneous drainage to transluminal endoscopic drainage with or without percutaneous endoscopic gastrostomy access for laparoscopic *** series have reached higher success rates of 79%-93%,and even 100%,using transcystic multiple drainage *** is becoming evident that transluminal endoscopic drainage treatment of walledoff NP without a necrosectomy is *** further refinement of the drainage procedures,a paradigm shift from necrosectomy to drainage is inevitable.

关键词： Delay until liquefaction Infected necrotizing pancreatitis Minimally invasive treatment Transluminal endoscopic drainage/necrosectomy Walled-off pancreatic necrosis

Quantifying entanglement in terms of an operational way

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Chinese Physics B 2021年第2期30卷 185-189页

作者： Deng-Hui yu chang-Shui yu School of Physics Dalian University of TechnologyDalian 116024China DUT-BSU Joint Institute Dalian University of TechnologyDalian 116024China

We establish entanglement monotones in terms of an operational approach,which is closely connected with the state conversion from pure states to the objective state by the local operations and classical *** is shown that any good entanglement quantifier defined on pure states can induce an entanglement monotone for all density ***,we show that our entanglement monotone is the maximal one among all those having the same form for pure *** some special cases,our proposed entanglement monotones turn to be equivalent to the convex roof construction,which hence gain an operational *** examples are given to demonstrate different cases.

关键词： quantum entanglement entanglement measure quantum resource theory

A Formula of General Solution for a Class of Homogeneous Trinomial Recurrence of Variable Coefficients with Two Indices

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Wuhan University Journal of Natural Sciences 2005年第5期10卷 828-832页

作者： yu Dan yu chang-an School of Computer Wuhan University Wuhan 430072 Hubei China School of Mathematics and Statistics Wuhan University Wuhan 430072 Hubei China

In practice, it is very difficult to find the solution of recurrence relation by using the characteristic roots. By applying iteration and induction we present an explicit formula of general solution for a class of homogeneous trinomial recurrence of variable coefficients with two indices. It provides a concrete and applicable model to solve the relevant problem with computer.

关键词： a formula of general solution homogeneous trinomial recurrence variable coefficients two indices

The Analysis of a Griffith Crack Embedded in a Thermo-poro-elastic Medium

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Acta Mechanica Solida Sinica 2023年第5期36卷 734-744页

作者： yu Tan Yi-en Wang chang Liu College of Environment and Civil Engineering Chengdu University of TechnologyChengdu 610059China School of Architecture and Civil Engineering Xihua UniversityChengdu 610039China School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China

The analytical solution of a thermo-poro-elastic medium in static state weakened by a Griffith crack with finite width is *** virtue of the Fourier cosine and sine integral transform techniques,the mixed boundary-value problem is formulated as three pairs of dual integral equations,which are solved with the help of the Abel *** addition,the stress intensity factor of mode Ⅰ and the crack surface displacement are presented *** examples are performed to show the distribution of displacement and stress over the thermo-poro-elastic *** results indicate that the thermal load will increase or decrease the crack surface displacement,but has a weak influence on the stress intensity *** present work may benefit future engineering applications.

关键词： Thermo-poro-elastic medium Analytical solution Grifﬁth crack Stress intensity factor

Commuting variety of Witt algebra

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Frontiers of Mathematics in China 2018年第5期13卷 1179-1187页

作者： yu-Feng YAO Hao chang Department of Mathematics Shanghai Maritime University Shanghai 201306 China School of Mathematics and Statistics Central China Normal University Wuhan 430079 China

Let g = W1 be the Witt algebra over an algebraically closed field k of characteristic p 〉 3, and let ∮（g） = {（x,y） ∈ g×g [x,y] = 0} be the commuting variety of g. In contrast with the case of classical Lie algebras of P. Levy [J. Algebra, 2002, 250： 473-484], we show that the variety ∮（g） is reducible, and not equidimensional. Irreducible components of ∮（g） and their dimensions are precisely given. As a consequence, the variety ∮（g） is not normal.

关键词： Witt algebra irreducible component dimension commuting variety

Borel Subalgebras of the Witt Algebra

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Acta Mathematica Sinica,English Series 2015年第8期31卷 1348-1358页

作者： yu Feng YAO Hao chang Department of Mathematics Shanghai Maritime University Department of Mathematics East China Normal University

Let F be an algebraically closed field of characteristic p 〉 3, and g be the Witt algebra over F. Let N be the nilpotent cone of g. An explicit description of N is given, so that the conjugacy classes of Borel subalgebras of g under the automorphism group of g are determined. In contrast with only one conjugacy class of Borel subalgebras in a classical simple Lie algebra, there are two conjugacy classes of Borel subalgebras in g. The representatives of conjugacy classes of Borel subalgebras, i.e.,the so-called standard Borel subalgebras, are precisely given.

关键词： Witt algebra Borel subalgebra nilpotent element nilpotent cone automorphism group