摘要：In clinical settings,tantalum(Ta)is extensively implemented as a bone implant *** is highly stable and biocompatible in vivo,being one of the metallic biomaterials having high affinity for bone ***,since Ta is a refractory metal,its application as bone implant material is *** recently,additive manufacturing technology has introduced a novel approach to producing Ta *** present study compared the microstructure,surface and mechanical characteristics,and in vitro and in vivo biological characteristics of selective laser melted Ta(SLM Ta),selective laser melted titanium alloy Ti6Al4V with Ta coating(SLM Ti6Al4V with Ta coating),and selective laser melted Ti6Al4V(SLM Ti6Al4V).Results indicate that SLM Ta possesses superior mechanical characteristics contrasted with SLM Ti6Al4V and SLM Ti6Al4V with Ta ***,SLM Ta has anti-inflammatory activity,excellent osseointegration performance,and osteogenic *** fabricated an SLM porous Ta bone plate and employed it for internal fixation of ulnar and radius fractures,which has been known to promote fracture ***,the SLM porous Ta bone plate could form an integrated bone plate structure with the bone tissue at the implant ***,the porous structure of the plate minimizes its elastic modulus and eliminates stress shielding,leaving no need for further surgical *** conclusion,the SLM porous Ta bone plate meets the performance requirements(stimulating bone regeneration,non-stress shelter,and no need for second surgery)of an ideal bone plate and may revolutionize the field of internal fixation bone plates for fractures.

摘要：Traditional passive vibration absorbers are effective only when their natural frequencies are close to those of the excitations. To solve this problem, a vibration absorber with time-delayed feedback control is proposed to suppress vibration of the primary system under excitation with changing frequency. Firstly, the mechanical model of the delay coupled system is established. Then, the displacement transfer ratio of the system is obtained. The stability of the system is analyzed since delay may result in destabilization. Next, in order to design the control parameters, the vibration absorption performances of the proposed time-delayed vibration absorber are studied. The vibration absorption region is shown. The results show that time-delayed feedback control is able to change the response of the system. The effective vibration absorption frequency band is adjustable by tuning the control gain and time delay. The effective frequency band can be widened when choosing appropriate control parameters. The vibration absorption performances can be greatly improved by the time-delayed absorber. In addition, the optimum control parameters are obtained. Finally, the experimental prototype is constructed. Several tests with different control parameters are taken. The experimental and analytical results match quite well.

摘要：本文集中关注20世纪80年代后当代美国学者杰弗里·哈特曼的批评主旨。作者指出,哈特曼更多地关注文学批评的社会功能,他在主张赋予审美以其应有的尊严的同时,也反对文学研究对社会学的过度忽视。因此,他以大屠杀研究为突破口,将维护艺术自身形式要素特征和杜绝艺术麻木不仁的防御姿态结合起来,选择了证词录像作为再现大屠杀历史的方式。作为一种文学叙事,证词录像既克服了实证主义史学家所称的客观真实,又克服了现代媒体文化带来的思维和精神惰性,以艺术的真实和想象唤起大众对外在世界的强烈感受,从而实现了其独特的述行功能。

摘要：Much attention has been paid for the synthesis of dimethyl carbonate(DMC) by urea indirect alcoholysis method, which had not been actually industrialized by now. The rigorous full process model was then necessary to optimize the process with heat integration. In this paper, a full process was designed and optimized for the DMC synthesis by urea indirect alcoholysis method based on Aspen Plus *** technological analysis was developed to find how the process was influenced by the three main recycled materials of methanol, 1,2-propylene glycol(PG) and mixture of DMC–methanol. Simultaneously,the thermal optimization was taken into account for energy saving and the optimized process was proposed with heat integration. Moreover, the economic evaluation was implemented for the optimized process with total annualized cost(TAC) and cost of product(COP) according to the plant investment and operations. It was found that the 11.6% decrease in TAC was obtained for the optimized process compared to the original designed process. The COP analysis showed that the process was economically efficient for the production of DMC from urea and methanol.

摘要：A novel extrusion-shearing(ES) composite process was designed to fabricate fine-grained, high strength and tough magnesium alloy. The structural parameters of an ES die were optimized by conducting an orthogonal simulation experiment using finite element software Deform-3D, and Mg-3 Zn-0.6 Ca-0.6 Zr(ZXK310) alloy was processed using the ES die. The results show that the optimized structural parameters of ES die are extrusion angle(α) of 90°, extrusion section height(h) of 15 mm and inner fillet radius(r) of 10 mm. After ES at an extrusion temperature and a die temperature of 350 °C, ZXK310 alloy exhibited good ES forming ability, and obvious dynamic recrystallization occurred in the forming area. The grain size decreased from 1.42 μm of extrusion area to 0.85 μm of the forming area. Owing to the pinning of second phase and formation of ultrafine grains, the tensile strength, yield strength and elongation of alloy reached 362 MPa, 289 MPa and 21.7%, respectively.

摘要：A novel bi-functional photorefractive acrylate polymer with pendant carbazolyl groups and azo derivatives as side chains was synthesized. Photorefractive experiments showed a high two-beam coupling gain coefficient of 93 cm(-1), diffraction efficiency of 12% and electro-optic coefficient of 26 pm/V were obtained.

摘要：透过南阳汉画像砖图案艺术反思当代图案艺术设计。概括南阳汉画像砖产生的时代背景。从图案题材、构成形式、工艺表现三方面剖析南阳汉画像砖图案艺术之美学,总结其美学价值。继而厘清南阳汉画像砖图案艺术与当代图案设计的相通性,以古鉴今,审视当代图案艺术设计。南阳汉画像砖图案艺术设计对于当代图案艺术设计具有借鉴意义。随着时代消费方式的升级,当代图案设计应当立足于文化,取材于生活,以情感化的设计方式为图案设计灌注全新的创作理念。该研究可为当代图案艺术的设计方式提供参考。

摘要：As a great threat to all livings on earth,waste artificial plastics now are everywhere,from oceans to our cells[1].The world cannot withstand the growing waste plastic in million tonnes every year,which has already caused environmental pollution and economic losses[2].Besides the efforts for preparing novel plastics with the self‐decomposition ability,methods are needed to clear away these waste plastics leftover from history or recycle well this organic carbon resource[3].Photocatalysis is a potential solution for the conversion of waste plastics under mild *** this perspective,we highlight the effect of photocatalytic approaches toward the generation of low carbon number organic products(C_(n) products,n≤8)from waste plastics,which can proceed under an inert or aerobic ***,critical analysis of the carbon source in products is necessary to reveal the active species for the C–X bonds(X=C,N,and O)cleavage of ***,we outline potential avenues for further development of this emerging field to enhance the yield of C_(n)(n≤8)products from waste plastics.

摘要：Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports(CeO2(nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.

摘要：AM50-4%(Zn,Y)alloy with a Zn/Y mole ratio of6:1was subjected to thermal analysis,and the results were used for designing a two-step progressive solution treatment *** effects of solution and aging treatments on the microstructure and mechanical properties of the AM50-4%(Zn,Y)alloy were investigated using OM,XRD,SEM/EDS,TEM,tensile test and hardness *** experimental results demonstrated that the two-step progressive solution treatment could make theΦandβphases sufficiently dissolve into the matrix which possessed higher supersaturated degree of the dissolved solute compared with the one-step solution *** resulted in a certain enhancement of the precipitation strengthening effect during the subsequent aging *** precipitation of theФphase had a greater impact on the comprehensive mechanical properties of the alloy thanβphase precipitation when the aging treatment was performed at180℃.The peak aging strength of the AM50-4%(Zn,Y)alloy which was subjected to the two-step progressive solution treatment process(345℃for16h and375℃for6h)was obtained after the aging treatment at180℃for12h.