工程施工中金属架构质量管理量化标准体系研究

由于目前现有的标准体系量化指标单一,无法准确判断出金属架构质量,不利于金属架构质量管理,为此提出工程施工中金属架构质量管理量化标准体系研究。多方面选取金属架构质量管理量化指标,并结合主观赋权法以及客观赋权法计算金属架构质量管理量化指标权值,利用指标权值组建金属架构质量管理量化目标函数,并利用量化矩阵对金属架构质量管理量化分析,根据分析结果确定金属架构质量管理量化等级,以此搭建了一个完整的金属架构质量管理量化标准体系,进而完成了工程施工中金属架构质量管理量化标准体系研究。

接触网金属架构埋设施工方案比较

通过对国内、外不同接触网金属架构在隧道内、桥梁上埋设方案的比较 ,优化出预埋平板构件的施工方案。

金属有机架构物Cu-BTC低温吸附储氢数值模拟研究

物理吸附储氢具有安全性能高、储氢密度大及充放氢速率快的优势,是一种极具应用潜力的储氢方式,其中金属有机架构物(MOFs)材料凭借其高度有序的孔隙结构和可调控特性已成为理想的吸氢材料。为探究吸附储氢过程热效应对储氢性能的影响,首先建立了吸附储氢数值模型并进行验证,随后对比分析了Cu-BTC与活性炭AX-21的储氢特性,并探究不同温度下Cu-BTC的储氢能力。计算结果表明:相较于AX-21,采用Cu-BTC作为吸附剂材料,常温下储氢量提升了12.8%;将储氢温度降至77 K时,Cu-BTC储罐的最高压力降至0.97 MPa,储氢质量相较于常温300 K提升了174%。以上结论可为Cu-BTC材料储氢研究提供参考。

金属有机架构物(MOFs)吸附储氢系统强化传热措施分析

选择MIL-101(Cr)并由溶剂热法合成,通过氢吸附平衡测试、在内容积为0.5 L储罐内进行充放氢试验和数值模拟,比较储罐内吸附床在添加膨胀石墨(ENG)和布置蜂巢状传热装置(HHED)下的储放氢性能。研究发现,在77.15~87.15 K、0~6 MPa范围,Toth方程预测氢在MIL-101(Cr)及其与ENG复合试样上吸附平衡数据的平均相对误差小于3.2%,氢在试样上的平均等量吸附热均为2.88 kJ/mol。77.15 K、0~3.5 MPa时,在与船舶燃料电池电力推进系统典型载荷适配的氢流率下,建立的二维数学模型对充气过程的数值模拟结果与测试值之间的平均相对偏差小于2%;与添加10 wt%的ENG相比,布置HHED的有效放气时间缩短14.3%、累计放气量增多15.5%、脱附率(DR)提高2.2%,在3.5 MPa时的可利用容积比率(UCR)提高10.6%。船用金属有机架构物(MOFs)储氢系统可选择布置HHED以缓解充放氢过程的热效应。

Synthesis and structures of cdq‑topological quaternary and(4,4,8)‑c topological quinary Zn‑MOFs with both oxalic acid and triazole ligands

Different solvothermal reactions of ZnC2O_(4)with oxalic acid(H_(2)ox)and 1,2,4-triazole(Htrz)successfully gave a new quaternary(NJTU-Bai83,NJTU-Bai=Nanjing Tech University Bai's group)and a new quinary(NJTU-Bai84)anionic metal-organic frameworks(MOFs),where NJTU-Bai83=(Me_(2)NH_(2))2[Zn_(3)(trz)_(2)(ox)_(3)]·2H_(2)O and NJTU-Bai84=(Me_(2)NH_(2))[Zn_(3)(trz)_(3)(ox)_(2)]·H_(2)O,respectively.With the[Zn_(2)(ox)4(trz)_(2)]secondary building unit(SBU)in NJTU-Bai83 replaced by the[Zn_(3)(ox)_(2)(trz)_(6)]and planar[Zn(ox)_(2)(trz)_(2)]ones in NJTU-Bai84,2D supramolecular building layers(SBLs)are changed from the A-layer and B-layer to another A-layer,while pillars are transformed from the tetrahedral[Zn(ox)_(2)(trz)_(2)]SBU to the irregular tetrahedral[Zn(ox)_(2)(trz)_(2)]and planar[Zn(ox)_(2)(trz)_(2)]SBUs.Thus,cdq-topological quaternary NJTU-Bai83 is tuned to(4,4,8)-c new topological quinary NJTU-Bai84.Two MOFs were well characterized by powder X-ray diffraction,thermogravimetric analysis,elemental analysis,etc.CCDC:2351819,NJTU-Bai83;2351820,NJTU-Bai84.

计算机虚拟化技术的分析与应用

当今计算机虚拟化技术,不论在硬件方面还是软件方面都快速地发展,企业级的虚拟化实施方案改变了IT基础架构,数据中心服务器的虚拟化应用已成为大势所趋。通过虚拟化技术实现原理的分析,及虚拟化技术优越性的总结,预示了虚拟化技术在计算机科学领域必将拥有光明的前景。

Topology optimization of microstructure and selective laser meltingfabrication for metallic biomaterial scaffolds

The precise design and fabrication of biomaterial scaffolds is necessary to provide a systematic study for bone tissue engineering. Biomaterial scaffolds should have sufficient stiffness and large porosity. These two goals generally contradict since larger porosity results in lower mechanical properties. To seek the microstructure of maximum stiffness with the constraint of volume fraction by topology optimization method, algorithms and programs were built to obtain 2D and 3D optimized microstructure and then they were transferred to CAD models of STL format. Ti scaffolds with 30% volume fraction were fabricated using a selective laser melting （SLM） technology. The architecture and pore shape in the metallic biomaterial scaffolds were relatively precise reproduced and the minimum mean pore size was 231μm. The accurate fabrication of intricate microstructure has verified that the SLM process is suitable for fabrication of metallic biomaterial scaffolds.

云计算中的虚拟化关键技术应用

虚拟化技术是云计算核心技术之一,它能解决整合计算机资源、提升工作性能、让资源利用率最大化等问题。文章分析服务器虚拟化的架构模式(裸金属架构和寄居架构)、桌面虚拟化架构模型及功能、存储虚拟化架构模型等,介绍了虚拟化技术面临的安全威胁问题。

计算机虚拟化技术的应用研究

在硬件方面和软件方面，计算机虚拟化技术都有着长足的发展，企业层面上的虚拟化方案变革了信息技术基础架构，中心服务器的虚拟化应用已成为主流。以虚拟化技术为载体进行原理分析，以及虚拟化技术好处的总结，预示了在计算机科学领域，虚拟化技术必将拥有美好的前景。

C3N4 modified with single layer ZIF67 nanoparticles for efficient photocatalytic degradation of organic pollutants under visible light

Uniformly distributed single layer of ZIF67-derived C3N4(ZIF67-C3N4)was synthesized and applied to the photocatalytic degradation of methylene blue(MB)under visible light.Results indicated that the obtained ZIF67-C3N4 has a maximum specific surface area of 541.392 m^2/g,which is much larger than that of raw C3N4 of 97.291 m^2/g.The investigation of C3N4 amount involved in ZIF67-C3N4 on the photoactivity revealed that 2.57 g ZIF67 with 0.3 g C3N4,which named ZIF67-C3N4(0.3)exhibited superior photocatalytic activities.More than 90%of MB at 10 mg/L was degraded within 70 min with the addition of 0.01 g ZIF67-C3N4(0.3),while this time required for raw C3N4 was over 140 min.The effects of pH of solution,initial concentration of MB and dosage of C3N4 in ZIF67-C3N4 composites on the photocatalytic efficiency for MB degradation were also evaluated.Quenching experiments indicated that the photo-induced holes(h^+)and superoxide radicals(O2-·)were mainly responsible for MB degradation.It is anticipated that the insertion of ZIF67 nanoparticles not only increases the adsorption capacity of C3N4 but also promotes the generation and migration of the photo-induced active species.

CO_2/CH_4 and CH_4/N_2 separation on isomeric metal organic frameworks

Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.

Synthesis of spherical tremella-like Sb2O3 structures derived from metal-organic framworks and its lithium storage properties

A novel spherical tremella-like Sb2O3 was prepared by using metal-organic frameworks(MOFs)method under a mild liquid-phase reaction condition,and was further employed as an anode material for lithium-ion batteries(LIBs).The effect of reaction temperature and time on morphologies of Sb2O3 was studied.The results from SEM and TEM demonstrate that the tremella-like Sb2O3 architecture are composed of numerous nanosheets with high specific surface area.When the tremella-like Sb2O3 was used as LIBs anode,the discharge and charge capacities can achieve 724 and 446 mA·h/g in the first cycle,respectively.Moreover,the electrode retains an impressive high capacity of 275 mA·h/g even after 50 cycles at 20 mA/g,indicating that the material is extremely promising for application in LIBs.

＂Societa Nazionale Officine di Savigliano＂： The History through Case Studies

Societa Nazionale Officine di Savigliano was a company specialized in railway constructions, metallic bridges and mechanical and electrical constructions. Between the end of the 19th century and the beginning of the 20th century, the company became well known in Europe especially for metallic constructions, having built the majority of metal bridges in the north of Italy such as the famous Paderno bridge （1887-1889）, one of the biggest arch bridge for the period. In the 1930s, the company built some interesting examples of steel frame buildings, applying the electrical welding technique, acquired in industrial constructions, to civil buildings. The steel frame was quite rare in Italian buildings, especially in the matter of civil constructions and Savigliano made an effort in modernizing the Italian construction system, through research and innovation. The paper will discuss some examples of Savigliano＇s works dating back to 1930, and in particular, it will present a specific example never studied before： the hangar at the Elmas military airport, in Cagliari （Sardinia）. The building is worth mentioning for the innovations experimented, as the new welding technique allowed a series of improvements in the construction process.

Structural and interfacial engineering of well‐defined metal‐organic ensembles for electrocatalytic carbon dioxide reduction

Electrochemical carbon dioxide reduction(CO_(2)RR)has been generally regarded as green technologies that can convert renewable energy such as sunlight and wind into fuels and valuable chemicals.However,the large‐scale implementation of CO_(2)RR is severely hindered by the lack of high‐performance CO_(2)RR electrocatalysts.Heterogeneous molecular catalysts and metal‐organic framework with well‐defined structure and high tunability of the metal centers and ligands show great promise for CO_(2)RR in terms of both fundamental understanding and practical application.Here,structural and interfacial engineering of these well‐defined metal‐organic ensembles is summarized.This review starts from the fundamental electrochemistry of CO_(2)RR and its evaluation criteria,and then moves to the heterogeneous molecular catalysts and metal‐organic framework with emphasis on the engineering of metal centers and ligands,their interaction with supports,as well as in situ reconstruction of metal‐organic ensembles.Summary and outlook are present in the end,with the hope to inspire and provoke more genuine thinking on the design and fabrication of efficient CO_(2)RR electrocatalysts.

Single crystal metal-organic framework constructed by vertically self-pillared nanosheets and its derivative for oriented lithium plating

This vertically self‐pillared(VSP)structure extends the application range of traditional porous materials with facile mass/ion transport and enhanced reaction kinetics.Here,we prepare a single crystal metal‐organic framework(MOF),employing the ZIF‐67 structure as a proof of concept,which is constructed by vertically self‐pillared nanosheets(VSP‐MOF).We further converted VSP‐MOF into VSP‐cobalt sulfide(VSP‐CoS2)through a sulfidation process.Catalysis plays an important role in almost all battery technologies;for metallic batteries,lithium anodes exhibit a high theoretical specific capacity,low density,and low redox potential.However,during the half‐cell reaction(Li++e=Li),uncontrolled dendritic Li penetrates the separator and solid electrolyte interphase layer.When employed as a composite scaffold for lithium metal deposition,there are many advantage to using this framework:1)the VSP‐CoS2 substrate provides a high specific surface area to dissipate the ion flux and mass transfer and acts as a pre‐catalyst,2)the catalytic Co center favors the charge transfer process and preferentially binds the Li+with the enhanced electrical fields,and 3)the VSP structure guides the metallic propagation along the nanosheet 2D orientation without the protrusive dendrites.All these features enable the VSP structure in metallic batteries with encouraging performances.

Construction of three high-nuclearity heterometallic cluster organic frameworks by introducing a bifunctional tripodal alcohol ligand

Three new metal organic frameworks,[Mn^(Ⅲ)_(4)Mn^(Ⅱ)_(8)O_(2)(4-thmpy)_(4)(O_(2)CPh)_(10)(OMe)_(2)(H_(2)O)_(2)]·3CH_(3)OH·4H_(2)O(1),[Mn^(Ⅱ)_(4)Co^(Ⅱ)_(6)O(4-thmpy)_(4)(O_(2)CPh)_(6)(H_(2)O)_(4)]·CH_(3)OH·3H_(2)O(2),and[Mn^(Ⅱ)_(4)Ni^(Ⅱ)_(6)O(4-thmpy)_(4)(O_(2)CPh)_(6)(H_(2)O)_(4)]·2CH_(3)OH·2H_(2)O(3),have been successfully synthesized by using 4-[tri-(hydroxymethyl)methyl]pyridine(4-thmpyH_(3))as ligand.Crystal structure analyses show that compound 1 is a disk-like twelve nuclear[Mn^(Ⅲ)_(4)Mn^(Ⅱ)_(8)]0D cluster.Compounds 2 and 3 are isomorphic,and the decanuclear heteronuclear cluster[Mn^(Ⅱ)_(4)Co^(Ⅱ)_(6)]node in compound 2 can be seen as a hyper-tetrahedron of four coboundary cubic alkanes[Mn^(Ⅱ)Co^(Ⅱ)_(3)O_(4)],then each ten-nuclear heteronuclear cluster[Mn^(Ⅱ)_(4)Co^(Ⅱ)_(6)]is connected by six 4-thmpy^(3-)with six adjacent decanuclear clusters[Mn^(Ⅱ)_(4)Co^(Ⅱ)_(6)],forming the NaCl-type 3D topological structure.Magnetic studies showed that there exist antiferromagnetic interactions between metal ions in 1-3.

Evolution of Zn(Ⅱ) single atom catalyst sites during the pyrolysis-induced transformation of ZIF-8 to N-doped carbons

The pyrolysis of zeolitic imidazolate frameworks(ZIFs) is becoming a popular approach for the synthesis of catalysts comprising porphyrin-like metal single atom catalysts(SACs) on N-doped carbons(M-N-C).Understanding the structural evolution of M-N-C as a function of ZIF pyrolysis temperature is important for realizing high performance catalysts.Herein,we report a detailed investigation of the evolution of Zn single atom catalyst sites during the pyrolysis of ZIF-8 at temperatures ranging from 500 to 900℃.Results from Zn L-edge and Zn K-edge X-ray absorption spectroscopy studies reveal that tetrahedral ZnN4 centers in ZIF-8 transform to porphyrin-like ZnN4 centers supported on N-doped carbon at temperatures as low as 600℃.As the pyrolysis temperature increased in the range 600-900℃,the Zn atoms moved closer to the N4 coordination plane.This subtle geometry change in the ZnN4 sites alters the electron density on the Zn atoms(formally Zn2+),strongly impacting the catalytic performance for the peroxidase-like decomposition of H2 O2.The catalyst obtained at 800℃(Zn-N-C-800) offered the best performance for H2 O2 decomposition.This work provides valuable new insights about the evolution of porphyrin-like single metal sites on N-doped carbons from ZIF precursors and the factors influencing SAC activity.

3D metal-organic frameworks based on lanthanide-seamed dimeric pyrogallol[4]arene nanocapsules

Two novel 3D metal-organic frameworks(MOFs)with cds network,{[Me NH_3]_7[Ln_8(Pg C_2)_2(H_2O)_y(HCOO)_7]}_n·x(Solvent)(FJI-Y4,FJI=Fujian Institute,Ln=Gd,y=12;FJI-Y5,Ln=Dy,y=11;Pg C_2=C-ethylpyrogallol[4]arene),based on unprecedented dimeric pyrogallol[4]arene-based Ln_8metal-organic nanocapsule(MONC)supramolecular building blocks and formate linkers,have been prepared under solvothermal conditions.To our best of knowledge,they present not only the first two examples of 3D hierarchical structures constructed from MONCs in metal-pyrogallol[4]arene system,but also the first two examples of MOFs based on lanthanide MONCs.Remarkably,the inner cavity volume of the Ln_8capsule in FJI-Y4 and FJI-Y5 is approximately151?~3,which is larger than those found in previous transition metal-seamed dimeric Pg C_n-based MONCs.Magnetic investigation on FJI-Y4 suggests a significant magnetocaloric effect(23.97 J kg^(-1)K^(-1),ΔH=7 T,2.5 K),while FJI-Y5 exhibits slow relaxation of the magnetization.

Three alkaline earth metal-organic frameworks based on fluorene-containing carboxylates:syntheses,structures and properties

Three metal-organic frameworks,{[Mg_2(MFDA)_2(DMF)_3]·0.5H_2O}_n(1),{[Ca(MFDA)(DMF)(H_2O)]·0.5DMF}_n(2)and[Ca(MFDA)(DMF)_2]_n(3)(DMF=N,N-dimethylformamide)have been synthesized by the solvothermal reactions between the ligand 9,9-dimethylfluorene-2,7-dicarboxylic acid(H_2MFDA)and the corresponding metal salts,respectively.The single crystal X-ray structural analyses reveal that compounds 1-3 display three-dimensional structures based on the M(Ⅱ)-O-C chains.It is interesting that the MFDA ligands in 1-3 have different dihedral angles between the two carboxylate groups ranging from 9.9(1)°to 41.8(2)°.All of compounds exhibit strong ligand-centered blue emissions under UV lights.Their thermal properties have also been studied.

Highly efficient and broad electromagnetic wave absorbers tuned via topology-controllable metal-organic frameworks

Advanced electromagnetic(EM)wave absorbing materials with strong absorption and broad bandwidth are important for military stealth and elimination of microwave pollution in consumers’electronics.Metal organic framework(MOF)-derived metal/carbon hybrids with ordered structure are significantly urgent in this field.In this contribution,we presented a design strategy of hollow cage-like or solid box-like magnetic/dielectric Fe/Co/C and dielectric Fe/Mn/C EM wave absorbing nanomaterials via pyrolyzing Prussian blue’s analogs with controllable topology and phase composition.The solid box-like Fe/Co/C and hollow cage-like Fe/Mn/C showed favorable absorption property with a broad effective absorption bandwidth(EAB)and a low reflection loss(RL).Especially,the EAB of 8.8 GHz at a thickness of 2.5 mm for solid box-like Fe/Co/C nanocomplex prepared at 900℃is a new record for this type of materials.The design and tuning strategy for EM wave absorbers derived from topology-controllable MOF is important for EM functional materials possessing great potential in military stealth and consumers’electronics.