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Communications in Theoretical Physics 2009年第11期52卷 784-790页

作者： zhang lin-lin liu Xi-Qiang School of Mathematical Sciences Liaocheng University Liaocheng 252059 China

In this paper, using the generalized （G1/G）-expansion method and the auxiliary differential equation method, we discuss the （2＋1）-dimensional canonical generalized KP （CGKP）, KdV, and （2＋1）-dimensional Burgers equations with variable coetticients. Many exact solutions of the equations are obtained in terms of elliptic functions, hyperbolic functions, trigonometric functions, and rational functions.

关键词： generalized (G1/G)-expansion method auxiliary equation exact solution

Effect of Coarse Aggregate Size on and Crack Opening in Normal and Relationship between Stress High Strength Concretes

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Journal of Materials Science & Technology 2005年第5期21卷 691-700页

作者： Jun zhang Qian liu lin WANG Department of Civil Engineering Tsinghua University Beijing 100084 China

Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still limited. In the present paper, the effect of coarse aggregate size （single grade of 5～10, 10～16, 16～20 and 20～25 mm） on stress-crack opening （σ-w） relation in normal and high strength concretes （compressive strength of 40 and 80 MPa, respectively） was studied. The investigation was based on three-point bending tests implemented by fictitious crack analysis. The result shows that coarse aggregate size and cement matrix strength significantly influence the shape of σ-w curve. For a given total aggregate content, in normal strength concrete, smaller size of aggregate leads to a high tensile strength and a sharp stress drop after the peak stress. The smaller the coarse aggregate, the steeper the σ-w curve. By contrast, in high strength concrete, the effect of aggregate size on σ-w relation almost vanishes. A similar σ-w relation is obtained for the concrete except for the case of 20～25 mm coarse aggregate size. The stress drop after the peak stress is more significant for high strength concrete than that for normal strength concrete. Meanwhile, the smaller the coarse aggregate size, the higher the flexural strength. Fracture energy and characteristic length increase with increasing coarse aggregate size in both normal and high strength concretes.

关键词： Aggregate size Stress-crack opening relation Fracture energy Bending test

Carbon aerogels for electric double-layer capacitors

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Rare Metals 2006年第Z1期25卷 51-57页

作者： zhang lin liu Hongbo WANG Ming liu Wei College of Materials Science and Engineering Hunan University Changsha 410082 China College of Materials Science and Engineering Hunan University Changsha 410082 China College of Materials Science and Engineering Hunan University Changsha 410082 China College of Materials Science and Engineering Hunan University Changsha 410082 China

In this study, carbon aerogels were derived via the pyrolysis of resorcinol-formaldehyde (RF) aerogels, which were cost-effectively manufactured from RF wet gels by an ambient drying technique instead of conventional supercritical drying. By varying the R/C ratio (molar ratio of resorcinol to catalyst), mesoporous carbon aerogels with high specific surface area were prepared successfully and further investigated as electrode materials for electric double-layer capacitors (EDLCs). The textural properties of carbon aerogels obtained were characterized by nitrogen adsorption/desorption analysis and SEM. The electrochemical performances of carbon aerogels were investigated by impedance spectroscopy, galvanostatic charge/discharge and cyclic voltammetry methods. The results show that BET surface area and specific capacitance increase with R/C ratio, the maximum values of 727 m2·g-1 and 132 F·g-1 are achieved at R/C ratio will of 300. Increasing R/C ratio increase the average pore size of carbon aerogel electrode, which has improved the rate capability. Furthermore, EDLC with carbon aerogel electrodes has an excellent stability at large discharge current and long cycle life.

关键词： carbon aerogel electric double-layer capacitors texture electrochemical performance

3D face registration based on principal axis analysis and labeled regions orientation

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Journal of Systems Engineering and Electronics 2009年第6期20卷 1324-1331页

作者： Guo Zhe zhang Yanning lin Zenggang liu Yantong Shaanxi Key Lab. of Speech & Image Information Processing School of Computer Science Chang'an Campus of Northwestern Polytechnical Univ. Xi'an 710129 P. R. China

A novel multi-view 3D face registration method based on principal axis analysis and labeled regions orientation called local orientation registration is *** pre-registration is achieved by transforming the multi-pose models to the standard frontal model＇s reference frame using the principal axis analysis *** significant feature regions, such as inner and outer canthus, nose tip vertices, are then located by using geometrical distribution *** regions are subsequently employed to compute the conversion parameters using the improved iterative closest point algorithm, and the optimal parameters are applied to complete the final *** results implemented on the proper database demonstrate that the proposed method significantly outperforms others by achieving 1.249 and 1.910 mean root-mean-square measure with slight and large view variation models, respectively.

关键词： local orientation registration principal axis analysis label regions orientation iterative closest point.

Effect of Melt Superheating Treatment on Directional Solidification Interface Morphology of Multi-component Alloy

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Journal of Materials Science & Technology 2011年第7期27卷 668-672页

作者： Changshuai Wang Jun zhang lin liu Hengzhi Fu State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi an 710072 China

The influence of melt superheating treatment on the solid/liquid （S/L） interface morphology of directionally solidified Ni-based superalloy DZ125 is investigated to elucidate the relationship between melt characteristic and S/L interface stability. The results indicate that the interface morphology is not only related to the withdrawal velocity （R） but also to the melt superheating temperature （Ts） when the thermal gradient of solidification interface remains constant for different Ts with appropriate superheating treatment regulation. The interface morphology changes from cell to plane at R of 1.1 μm/s when Ts increases from 1500°C to 1650°C, and maintains plane with further elevated Ts of 1750°C. However, the interface morphology changes from coarse dendrite to cell and then to cellular dendrite at R of 2.25 μm/s when Ts increases from 1500°C to 1650°C and then to 1750°C. It is proved that the solidification onset temperature and the solidification interval undergo the nonlinear variation when Ts increases from 1500°C to 1680°C, and the turning point is 1650°C at which the solidification onset temperature and the solidification interval are all minimum. This indicates that the melt superheating treatment enhances the solidification interface stability and has important effect on the solidification characteristics.

关键词： Melt superheating treatment Directional solidification interface morphology Solidification characteristics Multi-component alloy

Growth characteristics of directionally solidified Al_2O_3/YAG/ZrO_2 ternary hypereutectic in situ composites under ultra-high temperature gradient

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International Journal of Minerals,Metallurgy and Materials 2011年第1期18卷 121-125页

作者： Hai-jun Su Jun zhang lin liu Heng-zhi Fu State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

Oxide eutectic ceramic in situ composites have attracted significant interest in the application of high-temperature structural materials because of their excellent high-temperature strength,oxidation and creep resistance,as well as outstanding microstructural *** directionally solidified ternary Al2O3/YAG/ZrO2 hypereutectic in situ composite was successfully prepared by a laser zone remelting method,aiming to investigate the growth characteristic under ultra-high temperature *** microstructures and phase composition of the as-solidified hypereutectic were characterized by using scanning electron microscopy（SEM）,energy dispersive spectroscopy（EDS）,and X-ray diffraction（XRD）.The results show that the composite presents a typical hypereutectic lamellar microstructure consisting of fine Al2O3 and YAG phases,and the enriched ZrO2 phases with smaller sizes are randomly distributed at the Al2O3/YAG interface and in Al2O3 *** power and scanning rate strongly affect the sample quality and microstructure ***,coarse colony microstructures were also observed,and their formation and the effect of temperature gradient on the microstructure were discussed.

关键词： eutectics ceramic materials microstructure thermal gradients remelting solidification

Immunotoxicity Effect of Benzo[α]Pyrene on Scallop Chlamys farreri

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Journal of Ocean University of China 2009年第1期8卷 89-94页

作者： zhang lin PAN Luqing liu Jing The Key Laboratory of Mariculture Ministry of Education Ocean University of China Qingdao 266003 P. R. China

The toxic effects of benzo[α]pyrene （B[α]P） at different concentrations （0.1, 0.5, 1, 2.5 and 7.5 μgL^-1） on scallop （Chlamys farreri） immune system were studied. The results showed that B[α]P had significant toxic effects on the haemocyte counts, neutral red uptake, phagocytosis, bacteriolytic and antibacterial activity （P〈0.05）, while the seawater control and acetone control had no significant differences. The haemocyte counts, neutral red uptake, phagocytosis and bacteriolytic activity in all B[α]P treatment groups as well as antibacterial activity in groups of 0.5, 1, 2.5 and 7.5 μgL^-1·B[α]P decreased significantly （P〈0.05）. Some of these indices tended to be stable on the sixth day and others on the ninth day, and the indices showed clear time- and concentration-response to B[α]E Bactenolytic activity in 0.1 μgL^-1 B[α]P treatment group and antibacterial activity in 0.1 ggLl and 0.5 μgL^-1 B[α]P treatment groups increased at the beginning of exposure and reached their peaks on day 1 and day 6, respectively. Following that, both activities decreased gradually and became stable after day 9. When all the indices reached stability, they were significantly lower than those in control group （P〈0.05）, except for antibacterial activity in 0.1 μgLl B[α]P treatment group （P〉0.05）. Thus, B[α]P has evident toxic effects on scallop immune system, which supports the view that a relationship exists between pollution and lmmunomodulation in aquatic organisms.

关键词： benzo[α]pyrene (B[α]P) Chlamysfarreri haemocyte counts neutral red uptake phagocytosis bacteriolytic activity antibacterial activity

Study on patterns and chemical features of NO effect on marine phytoplankton growth

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Science China Chemistry 2005年第4期48卷 376-384页

作者： zhang Zhengbin lin Cai liu Chunying XING Lei WU Zhenzhen SUN Feng Institute of Marine Chemistry Ocean University of ChinaQingdao 266003China Institute of Marine ChemistryOcean University of ChinaQingdao 266003China Institute of Marine ChemistryOcean University of ChinaQingdao 266003China Institute of Marine ChemistryOcean University of ChinaQingdao 266003China Institute of Marine ChemistryOcean University of ChinaQingdao 266003China Institute of Marine ChemistryOcean University of ChinaQingdao 266003China

This article discusses the patterns of NO effect on marine phytoplankton growth from chemical *** experimental results of four algae,which are Platymonas hal-golandica ***,Platymonas subcordiformis,Skeletonema costatum and Nitzschia closterium farma minutissima,are as follows:(i) In f/2 medium or f/50 medium,the growth of these four algae was obviously promoted or inhibited when nitric oxide of different concentrations was added once or twice each day during the cultivation;(ii) The NO effects on the growth of marine phytoplankton are in normal *** phytoplankton has different optimum NO concentration,which is consistent with the influence of NO on the growth of high plants;(iii) The effect of NO on Platymonas halgolandica ***,which is a food alga,is different from that on the red tide algae Skeletonema costatum and Nitzschia closterium farma *** authors put forward a new opinion that every alga has its own NO threshold *** the above results may provide new clues to understand the formation of red tide.

关键词： nitric oxide (NO), marine phytoplankton (red tide algae and food algae), optimum NO concentration, NO threshold concentration, influencing patterns.

Early clinical outcome with lens position adjustment following implantable collamer lens surgery

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International Journal of Ophthalmology(English edition) 2024年第9期17卷 1654-1658页

作者： Qian zhang Bo Zhao Xue-Fei Yang zhang-lin liu Yue Huang Refractive Surgery Department Tianjin Key Laboratory of Retinal Functions and DiseasesTianjin Branch of National Clinical Research Center for Ocular DiseaseEye Institute and School of OptometryTianjin Medical University Eye HospitalTianjin 300384China Refractive Surgery Department Aier Eye HospitalTianjin UniversityTianjin 300190China

AIM:To observe early clinical outcome with lens position adjustment following the implantable collamer lens(ICL)***:Sixty patients were selected for this retrospective *** eye from each patient received Toric ICL for astigmatism correction,and the other received non-astigmatic ICL surgery using horizontal *** with higher postoperative arch height were selected,and their non-astigmatic eye clinical outcome were observed after ICL surgery at 1wk,1,and *** clinical measurements included uncorrected visual acuity(UCVA),intraocular pressure(IOP),refractive state,corneal endothelium cell count,and arch *** months later,the ICL in each patient’s non-astigmatic eye was adjusted to the vertical from the horizontal *** results were compared before and 1wk,1,and 3mo after ***:UCVA and IOP were significantly reduced 1wk after position adjustment compared to 1wk after ICL implantation(Plium cell count 1wk,1,and 3mo after adjusting position compared to 1wk,1,and 3mo after ICL implantation(P0.05).CONCLUSION:Early positioning adjustment postphakic ICL implantation can benefit patients with adjusted arch height or higher *** the good clinical effects,the doctors should pay attention to the potential for adverse effects on UCVA and corneal endothelium cells following early position adjustment after posterior chamber phakic ICL implantation.

关键词： implantable collamer lens myopia lens positional adjustment arch height intraocular pressure

Effect of cooling rates on dendrite spacings of directionally solidified DZ125 alloy under high thermal gradient

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Rare Metals 2009年第6期28卷 633-638页

作者： zhang Weiguo liu lin ZHAO Xinbao HUANG Taiwen YU Zhuhuan QU Min FU Hengzhi State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

The dendrite morphologies and spacings of directionally solidified DZ125 superalloy were investigated under high thermal gradient about 500 K/cm. The results reveal that, with increasing cooling rate, both the spacings of primary and secondary dendrite arms decrease, and the dendrite morphologies transit from coarse to superfme dendrite. The secondary dendrite arms trend to be refined and be well developed, and the tertiary dendrite will occur. The predictions of the Kurz/Fisher model and the Hunt/Lu model accord basically with the experimental data for primary dendrite arm spacing. The regression equation of the primary dendrite arm spacings 21 and the cooling rate Vc is λ1 = 0.013 Vc^-0.32. The regression equation of the secondary dendrite arm spacing λ2 and the cooling rate Vc is λ2 = 0.00258 Vc^-0.31, which gives good agreement with the Feurer/Wunderlin model.

关键词： directional solidification superalloy thermal gradient cooling rate dendrite arm spacing