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Quantitative Structure-biodegradability Relationship Study about the Aerobic biodegradation of Some Aromatic Compounds

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Chinese Journal of Structural Chemistry 2011年第3期30卷 368-375页

作者：荆国华李小林周作明 department of Environmental Science & engineering Huaqiao University

10 quantum chemical descriptors of 21 aromatic compounds have been calculated by the semi-empirical quantum chemical method AM1. The Quantitative Structure-biodegradability Relationships （QSBR） studies were performed by the multiple linear regression （MLR）, principal component regression （PCR） and back propagation artificial neural network （BP-ANN）, respectively. The root mean square error （RMSE） of the training and validation sets of the BP-ANN model are 0.1363 and 0.0244, the mean absolute percentage errors （MAPE） are 0.1638 and 0.0326, the squared correlation coefficients （R^2） are 0.9853 and 0.9996, respectively. The results show that the BP-ANN model achieved a better prediction result than those of MLR and PCR. In addition, some insights into the structural factors affecting the aerobic biodegradation mechanism were discussed in detail.

关键词： aromatic compounds quantitative structure-biodegradability relationships,multiple linear regression principal component regression artificial neural network

Effect of Hot Torsion Parameters on Development of Ultrafine Ferrite Grains in Microalloyed Steel

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Journal of Iron and Steel Research International 2012年第1期19卷 47-52页

作者： B Eghbali department of Materials engineering Sahand University of Technology

Hot torsion testing was performed on a low carbon Nb-Ti microalloyed steel to study the effects of hot tor- sion parameters, strain and strain rate, on ultrafine ferrite grains production through dynamic strain-induced trans- formation, at a deformation temperature just above At3. The initiation and evolution of ultrafine ferrite grains were studied. The results show that the amount of strain and strain rate has conversely effect on the volume fraction and grain size of ultrafine ferrite grains. With increasing strain, the interior of austenite grains become activated as nucle- ation sites for fine ferrite grains. As a result, ferrite grains continuously nucleate not only at the former austenite grain boundaries but also inside the austenite grains which leads to a rapid increase in volume fraction of ultrafine grains. Increasing of strain rate reduces the tendency of ferrite grains coarsening so that ultrafine ferrite grains are achieved, while the volume fraction of ultrafine grains decreases at the same strain level.

关键词： dynamic strain induced transformation grain refinement ferrite hot torsion steel

Reconfigurable parallel mechanisms with planar five-bar metamorphic linkages

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Science China(Technological Sciences) 2014年第1期57卷 210-218页

作者： YE Wei FANG YueFa GUO Sheng department of Mechanical engineering Beijing Jiaotong University

This paper presents the idea of constructing reconfigurable limbs by integrating metamorphic linkages as *** planar five-bar metamorphic linkages that have three phases resulting from locking of motors are *** the assumption that the constraint exerted by the reconfigurable limb can switch between no constraint,a constraint force,and a constraint couple,the output motions of the metamorphic linkage in its two planar four-bar linkage phases are *** adding an appropriate joint to planar four-bar linkages with translational output,four planar five-bar linkages that can be employed in the construction of reconfigurable limbs are *** chains that can provide a constraint couple and a constraint force are synthesized based on screw *** limbs that have three configurations associated with the three distinct phases of the metamorphic linkages are assembled with planar five-bar metamorphic linkages and serial chains with four degrees of freedom.A class of reconfigurable parallel mechanisms are constructed by connecting a moving platform and a base with three identical reconfigurable *** degrees of freedom of the reconfigurable parallel mechanism in different configurations with the metamorphic linkages in different phases are ***,the actuation scheme for this kind of mechanisms is addressed.

关键词： reconfigurable limb planar five-bar metamorphic linkage screw theory reconfigurable parallel mechanism actuation scheme

Hydrodynamic Behavior of Curtainwall-Pile Breakwaters

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China Ocean engineering 2012年第4期26卷 685-698页

作者： O.Nejadkazem A.R.M.Gharabaghi department of Civil engineering Sahand University of Technology

A numerical model is developed that can predict the interaction of regular waves normally incident upon a curtainwall-pile breakwater; the upper part of which is a vertical wall and the lower part consists of an array of vertical piles. The numerical model is based on an eigenfunction expansion method, and utilizes a boundary condition nearby the vertical piles that accounts for wave energy dissipation. Numerical solution comprises a finite number of terms, which is a superposition of propagating waves and a series of evanescent waves. The modeling is validated by comparison with previous experimental studies and overall agreement between measurement and calculation is fairly good. The numerical results are related to reflection, transmission, and dissipation coefficient; wave nm-up, wave force, and wave overturning moment are also presented. Effect of porosity, relative draft, and relative water depth are discussed; the choice of suitable range of them is described. The relative draft is more effective for shallow water waves. Model shows decrease in relative draft and leads to reduction of relative wave force, overturning moment, and runup. It is shown that curtainwall- pile breakwaters can operate both effectively and efficiently in the range of relative draft between 0.15 and 0.75. The range 0.5 to 0.2 is also recommended for porosity.

关键词： curtainwall-pile breakwaters full wave mode reflection transmission run-up wave force wave overturning moment

Numerical modeling of friction stir welding using the tools with polygonal pins

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Defence Technology（防务技术） 2015年第3期11卷 229-236页

作者： M. MEHTA G.M. REDDY A.V. RAO A. DE Production engineering department BVM Engineering College Defense Metallurgical Research Laboratory Mechanical engineering department

Friction stir welding using the tools with polygonal pins is often found to improve the mechanical strength of weld joint in comparison to the tools with circular pins. However, the impacts of pin profile on the peak temperature, tool torque and traverse force, and the resultant mechanical stresses experienced by the tool have been rarely reported in a systematic manner. An estimation of the rate of heat generation for the tools with polygonal pins is challenging due to their non-axisymmetric cross-section about the tool axis. A novel methodology is presented to analytically estimate the rate of heat generation for the tools with polygonal pins. A three-dimensional heat transfer analysis of friction stir welding is carried out using finite element method. The computed temperature field from the heat transfer model is used to estimate the torque, traverse force and the mechanical stresses experienced by regular triangular, square, pentagon and hexagon pins following the principles of solid mechanics. The computed results show that the peak temperature experienced by the tool pin increases with the number of pin sides. However, the resultant maximum shear stress experienced by the pin reduces from the triangular to hexagonal pins.

关键词：搅拌摩擦焊接多边形管脚数值模拟摩擦搅拌焊接机械强度峰值温度机械应力

Catalytic Kinetic on the Thermal Decomposition of Ammonium Perchlorate with a New Energetic Complex Based on 3,5-Bis(3-pyridyl)-1H-1,2,4-triazole

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Chinese Journal of Structural Chemistry 2016年第12期35卷 1902-1911页

作者：高慧李冰靳晓东毕淑娴田晓燕刘万毅 department of Chemistry and Chemical engineering Ningxia University

A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911（1）,b = 10.2573（1）,c = 10.6393（1）？,α = 103.793（2）,β = 101.041（2）,γ = 107.918（3）o,V = 974.9（2）？~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^（-1）,M_r = 508.31,F（000） = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ（I）. In the title complex,Co（Ⅱ） ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3？-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate（AP） with complex 1 was explored by differential scanning calorimetry（DSC）. AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^（-1）,significantly higher than that of pure AP. By Kissinger＇s method,the ratio of Ea/ln（A） is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition.

关键词： 3 5-bis(3-pyridyl)-1H-1 2 4-triazole ammonium perchlorate catalytic thermal decomposition

Insight into the effect of Ge modification on the oxidation of NbSi2 from first-principles calculations

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Progress in Natural Science:Materials International 2021年第4期31卷 618-623页

作者： Changliang Wang Meifeng Li Chungen Zhou department of Materials Science and engineering Beihang University

The effect of Ge modification on the oxidation of Nb Si2was performed by using the first-principles method based on Density Functional Theory（DFT）. The O2molecule absorption configurations on the ideal NbSi2（001） surface with and without Ge substitution was constructed to study the initial oxidation behavior as well as oxygen diffusion in the bulk Nb Si2cell in the late oxidation stage. Ge substitution was found to decrease the absorption energy of O2molecule on the NbSi2（001） surface and therefore reduce the oxidation rate in the initial oxidation stage. The further linear synchronous transit（LST） calculation revealed that Ge substitution increased the energy barrier of O atom diffusion in the bulk Nb Si2cell and decreased the oxidation rate in the late stage.

关键词： Oxidation First-principles calculation NbSi2

BIFURCATION OF FLOW AND MASS TRANSPORT IN A CURVED BLOOD VESSEL

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Acta Mechanica Sinica 2003年第4期19卷 315-319页

作者：谭文长魏兰赵耀华 TAKASHI Masuoka department of Mechanics and engineering Science Peking University 100871 China department of Mechanical engineering Science Kyushu University Fukuoka 812-8581 Japan

A numerical analysis of flow and concentration fields of macromolecules in a slightly curved blood vessel was carried out. Based on these results, the effect of the bifurcation of a flow on the mass transport in a curved blood vessel was discussed. The macromolecules turned out to be easier to deposit in the inner part of the curved blood vessel near the critical Dean number. Once the Dean number is higher than the critical number, the bifurcation of the flow appears. This bifurcation can prevent macromolecules from concentrating in the inner part of the curved blood vessel. This result is helpful for understanding the possible correlations between the blood dynamics and atherosclerosis.

关键词： curved blood vessel bifurcation of flow steady flow mass transfer

Simulated and experimental studies of a multi-band symmetric metamaterial absorber with polarization independence for radar applications

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Chinese Physics B 2022年第5期31卷 703-710页

作者： Hema O.Ali Asaad M.Al-Hindawi Yadgar I.Abdulkarim Ekasit Nugoolcharoenlap Tossapol Tippo FatihÖzkan Alkurt Olcay Altintas Muharrem Karaaslan department of Communication engineering Sulaimani Polytechnic UniversitySulaimani 46001Iraq Medical Physics department College of Medicals and Applied ScienceCharmo UniversityChamchamal 46023SulaimaniaIraq department of Telecommunication engineering Faculty of EngineeringRajamangala University of Technology RattanakosinPhutthamonthonNakornprathom 73170Thailand department of Electrical and Electronics engineering Iskenderun Technical UniversityHatay 31100Turkey

We develop a simple new design for a multi-band metamaterial absorber(MTMA)for radar *** Simulation Technology(CST)Studio Suite 2018 was used for the numerical analysis and absorption *** simulated results show four high peaks at 5.6 GHz,7.6 GHz,10.98 GHz,and 11.29 GHz corresponding to absorption characteristics of 100%,100%,99%,and 99%,***,two different structures were designed and compared with the proposed *** proposed structure remained insensitive for any incident angle and polarization angle from 0°to60°.Moreover,negative constitutive parameters were retrieved *** support the simulated results,the proposed design was fabricated by using a computer numerical control-based printed circuit board prototyping machine and tested experimentally in a microwave *** absorption mechanism of the proposed MTMA is presented through the surface current and electric field *** novelties of the proposed structure are a simple and new design,ease of fabrication,low cost,durability,suitability for real-time applications and long-term stability given the fabrication technique and non-destructive measurement method and very high *** proposed structure has potential applications in C and X band frequency ranges.

关键词： multi-band metamaterials absorber polarization-independent negative parameters