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Characterization of Microstructure of Permanent Mold Cast Zinc Alloy ZA27

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材料热处理学报 2004年第5期25卷 174-179页

作者： CHENTi-jun LIYuan-dong HAOYuan StateKeyLabofAdvancedNonferrousMaterials LanzhouUniversityofTechnologyLanzhouChina

The microstructure of permanent mold cast zinc alloy ZA27 was examined by SEM and TEM after natural aging for 18 months. It was found that the primary a’ phase, peritectic and eutectic phases all decomposed into the equilibrium well-formed a+r| lamellae or irregular a+T| structure through cellular reaction. The cell colonies nucleated on the interdendritic eutectic T| layer and grew into the primary dendrites, thus first making the phase in the dendrite edges decompose, and then the a’ phase in the dendrite cores. The products from the a’ phase appeared in regular lamellae rather than irregular particles. In addition, a fine, dense transitional phase a’m containing 27.8 mass% Al, with a fee crystal structure and lattice parameter of about 0.4013nm, formed in lamellae. Copper was preferentially concentrated in Zn-rich n phase and existed in the form of Cu-rich e phase (CuZo,) particles, with hep crystal structure and parameters a=0.274nm, c=0.429nm and c/a=l .567.

关键词：显微结构硬模铸造 ZA27合金 SEM TEM

Aerodynamic stability of cable-supported bridges using CFRP cables

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第5期8卷 693-698页

作者： ZHANG Xin-jun YING Lei-dong College of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou 310014 China

To gain understanding of the applicability of carbon fiber reinforced polymer (CFRP) cable in cable-supported bridges, based on the Runyang Bridge and Jinsha Bridge, a suspension bridge using CFRP cables and a cable-stayed bridge using CFRP stay cables are designed, in which the cable’s cross-sectional area is determined by the principle of equivalent axial stiffness. Numerical investigations on the aerodynamic stability of the two bridges are conducted by 3D nonlinear aerodynamic stability analysis. The results showed that as CFRP cables are used in cable-supported bridges, for suspension bridge, its aerodynamic stability is superior to that of the case using steel cables due to the great increase of the torsional frequency; for cable-stayed bridge, its aerodynamic stability is basically the same as that of the case using steel stay cables. Therefore as far as the wind stability is considered, the use of CFRP cables in cable-supported bridges is feasible, and the cable’s cross-sectional area should be deter-mined by the principle of equivalent axial stiffness.

关键词： Cable-supported bridges Carbon fiber reinforced polymer (CFRP) cable Aerodynamic stability

Application of color structured light pattern to measurement of large out-of-plane deformation

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Acta Mechanica Sinica 2011年第6期27卷 1098-1104页

作者： Xing Lu jun-Hong Zhou dong-dong Liu Jue Zhang College of Engineering Peking University100871 Beijing China

Measurement of out-of-plane deformation is significant to understanding of the deflection mechanisms of the plate and tube *** this study,a new surface contouring technique with color structured light is applied to measure the out-of-plane deformation of structures with one-shot *** color fringe recognizing,decoding and triangulation processing for the captured images corresponding to each deformation state,the feasibility of the method is testified by the measurement of elastic deflections of a flexible square plate,showing good agreement with those from the calibrated displacement *** plastic deformation of two alloy aluminum rectangular tubes is measured to show the technique application to surface topographic evaluation of the buckling structures with large displacements.

关键词： Out-of-plane deformation Surface contouring Color structured light Plate deflection - Rectangular tube buckling

Complications of common bile duct stones: A risk factors analysis

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Hepatobiliary & Pancreatic Diseases International 2021年第4期20卷 361-365页

作者： dong jun Oh Ji Hyung Nam dong Kee Jang jun Kyu Lee Department of Internal Medicine Dongguk University Ilsan HospitalGoyang 10326Korea

Background: The latest guidelines recommended that common bile duct stones(CBDSs) should be removed, preferably endoscopically, regardless of the presence of symptoms or complications. However, the removal of CBDSs may not be feasible in very old patients or those with co-morbidities. In these cases, it is important to understand the risk factors for the development of CBDSs-related complications to decide whether or not to treat high-risk patients. Herein, we aimed to identify the risk factors for the development of complications after the diagnosis of CBDSs. Methods: The medical records of patients with CBDSs between October 2005 and September 2019 were retrospectively analyzed. All patients with radiologically-diagnosed CBDSs, including those who received treatment and those who did not, were analyzed. Results: A total of 634 patients were included and 95(15.0%) patients had CBDS-related complications during the mean follow-up period of 32.6 months. Forty-four(6.9%) high-risk patients remained asymptomatic and did not receive treatment during the follow-up period. In multivariate analyses, size of CBDSs ≥ 5 mm and no treatment within 30 days were independent risk factors for the development of complications. The spontaneous passage of CBDSs was proved radiologically in 9 out of 81(11.1%) patients within 30 days. Conclusions: It is recommended treating CBDSs within 30 days from the diagnosis, even in high-risk patients, especially if the size is larger than 5 mm.

关键词： Common bile duct stone Risk factors Obstructive jaundice Pancreatitis Cholangitis

Organic/inorganic nanocomposite polymer electrolyte

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Chinese Chemical Letters 2007年第2期18卷 185-188页

作者： Li Qi Shao jun dong State Key Laboratory of Electroanalytical Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China

The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocomposites membrane materials and their lithium salt complexes have been found thermally stable below 200 °C. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10(?6) S/cm.

关键词： Organic/inorganic nanocomposites Polymer electrolyte Polymer lithium battery Conductivity Characterization Thermal stability

A Construction of Maximal Linearly Independent Array

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Acta Mathematica Sinica,English Series 2010年第7期26卷 1331-1344页

作者： jun Wu dong Xue Li WANG College of Mathematics and Econometrics Hu'nan University Changsha 410082 P. R. China College of Mathematics and Information Science Guangzhou University Guangzhou 510006 P. R. China School of Mathematical Sciences South China Normal University Guangzhou 510631 P. R. China

Let M be a subset of r-dimensional vector space Vτ （F2） over a finite field F2, consisting of n nonzero vectors, such that every t vectors of M are linearly independent over F2. Then M is called （n, t）-linearly independent array of length n over Vτ（F2）. The （n, t）-linearly independent array M that has the maximal number of elements is called the maximal （r, t）-linearly independent array, and the maximal number is denoted by M（r, t）. It is an interesting combinatorial structure, which has many applications in cryptography and coding theory. It can be used to construct orthogonal arrays, strong partial balanced designs. It can also be used to design good linear codes, In this paper, we construct a class of maximal （r, t）-linearly independent arrays of length r ＋ 2, and provide some enumerator theorems.

关键词： maximal linearly independent array orthogonal array hamming weight

Neighbor Sum Distinguishing Total Colorings of Graphs with Bounded Maximum Average Degree

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Acta Mathematica Sinica,English Series 2014年第4期30卷 703-709页

作者： Ai jun dong Guang Hui WANG School of Science Shandong Jiao Tong University School of Mathematics Shandong University

A proper [h]-total coloring c of a graph G is a proper total coloring c of G using colors of the set [h] ={1, 2,..., h}. Let w（u） denote the sum of the color on a vertex u and colors on all the edges incident to u. For each edge uv ∈ E（G）, if w（u） ≠ w（v）, then we say the coloring c distinguishes adjacent vertices by sum and call it a neighbor sum distinguishing [h]-total coloring of G. By tndi∑ （G）, we denote the smallest value h in such a coloring of G. In this paper, we obtain that G is a graph with at least two vertices, if mad（G）〈 3, then tndi∑ （G） ≤k ＋ 2 where k = max{△（G）, 5}. It partially confirms the conjecture proposed by Pilgniak and Wolniak.

关键词： Total coloring neighbor sum distinguishing total colorings average degree

AN ANALYTICAL SOLUTION FOR THREE-DIMENSIONAL DIFFRACTION OF PLANE P-WAVES BY A HEMISPHERICAL ALLUVIAL VALLEY WITH SATURATED SOIL DEPOSITS

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Acta Mechanica Solida Sinica 2006年第2期19卷 141-151页

作者： Zhao Chenggang dong jun Gao Fuping School of Civil Engineering and Architecture Beijing Jiaotong University Beijing 100044 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

An analytical solution for the three-dimensional scattering and diffraction of plane P-waves by a hemispherical alluvial valley with saturated soil deposits is developed by employing Fourier-Bessel series expansion technique. Unlike previous studies, in which the saturated soil deposits were simulated with the single-phase elastic theory, in this paper, they are simulated with Biot＇s dynamic theory for saturated porous media, and the half space is assumed as a single-phase elastic medium. The effects of the dimensionless frequency, the incidence angle of P-wave and the porosity of soil deposits on the surface displacement magnifications of the hemispherical alluvial valley are investigated. Numerical results show that the existence of a saturated hemispherical alluvial valley has much influence on the surface displacement magnifications. It is more reasonable to simulate soil deposits with Biot＇s dynamic theory when evaluating the displacement responses of a hemispherical alluvial valley with an incidence of P-waves.

关键词： Biot's dynamic theory three-dimensional scattering hemispherical alluvial valley,analytical solution

Removal of phenol by activated alumina bed in pulsed high-voltage electric field

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Journal of Environmental Sciences 2007年第4期19卷 409-415页

作者： ZHU Li-nan MA jun YANG Shi-dong School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China

A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe^2＋. The removal rate of phenol could reach 72.1% when air aeration flow rate was 1200 ml/min, and 88.2% when 0.05 mmol/L Fe^2＋ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

关键词： pulsed high-voltage electric field hybrid gas-liquid electrical discharge activated alumina phenol Fenton's reaction water treatment