预应力高强钢绞线网加固钢筋混凝土板的试验研究

采用新型张拉锚固系统对钢绞线网施加预应力,研究预应力水平值对板加固效果的影响规律。对3块不同预应力水平加固板、1块非预应力加固板和1块对比板进行抗弯试验研究。试验结果表明:较对比板,预应力加固板的承载力、截面刚度大幅度提高,裂缝宽度明显减小;较非预应力加固板,其开裂荷载显著提高,屈服荷载、极限荷载、截面刚度均有提高,裂缝宽度减小;随预应力水平的提高,加固效果、钢绞线强度的利用率明显提高。对钢绞线的预应力损失进行分析,提出预应力加固板承载力的计算公式,计算结果与试验值吻合良好,可作为预应力钢绞线抗弯加固混凝土板理论分析和设计的参考。预应力高强钢绞线加固技术解决了非预应力加固方法钢绞线应变滞后、发生剥离破坏、高强度利用率低等缺点,是一种主动高效的加固技术,具有较高的推广应用价值。

不同方法加固足尺寸RC梁的抗弯性能

对4种常用加固方法加固的矩形截面钢筋混凝土梁的抗弯性能进行了对比试验研究.通过10根混凝土梁的抗弯加固试验,研究碳纤维布(carbon fiber sheet,CFS)、非预应力与预应力钢绞线和黏钢加固RC梁的受弯破坏特征,探讨4种加固方法对梁开裂荷载、屈服荷载、极限承载力和延性的影响,比较各种加固梁的裂缝扩展、挠度和刚度变化.研究表明:1)相比未加固梁,CFS、非预应力与预应力钢绞线和黏钢加固梁的开裂荷载分别提高了27.8%、59.7%、94.4%和73.6%;屈服荷载分别提高了12.4%、26.1%、36.2%和37.6%;极限承载力分别提高了48.0%、71.1%、74.6%和75.6%;极限挠度分别减小了23.6%、21.0%、31.1%和19.6%.2)正常使用状态下,预应力钢绞线加固效果优于非预应力钢绞线.3)钢绞线对提高梁二次刚度作用明显,而钢板作用较小.

预应力高强钢绞线网抗剪加固钢筋混凝土梁试验

采用新型张拉锚固系统,对剪跨比为2.2和1.65的预应力钢绞线U形抗剪加固梁各3根和1根未加固梁进行了对比试验,研究预应力水平、剪跨比对加固效果的影响规律。试验结果表明:预应力抗剪加固可提高梁的承载力、截面刚度;当预应力水平小于0.3时,承载力、截面刚度、钢绞线利用率随预应力水平的提高而提高;当预应力水平大于0.3时,加固梁的承载力随预应力水平的提高相对降低。建立了预应力高强钢绞线U形抗剪加固梁的承载力计算式,计算结果与试验值吻合良好。研究结果可为预应力钢绞线抗剪加固混凝土梁设计和施工提供参考。

后张无粘结预应力装配节点加固试验研究

采用碳纤维布和外包钢两种加固方法,对后张无粘结预应力装配梁、柱节点进行了低周反复加载试验研究。试验表明加固后的预应力装配梁、柱节点获得了令人满意的抗震特性,如自恢复能力和较大非线性位移下破坏较少等能力。分析了不同加固方法对后张无粘结预应力装配节点抗震性能的影响。

微波等离子体法沉积镍膜的研究

采用微波等离子镀膜机制备镍薄膜。该方法的特点是用纯金属镍为靶,用微波产生等离子体,用交流电源作为轰击电源,远程输运。使用XRD、SEM、EDS对采用微波等离子法沉积的薄膜进行表征,对实验结果进行分析,并对镀膜工艺进行了初步探索。

混合装配无粘结预应力梁加固试验研究

本文采用碳纤维布和外包钢两种加固方法,对6个混合装配无粘结预应力梁进行了低周反复加载试验。考虑了初始预应力度、后穿非预应力筋的强度、面积和不同加固方法等参数变化。试验表明:采用无粘结预应力混合装配的梁,在耗能和承载能力等方面比全预应力装配构件有所提高,加固后构件自恢复能力仍然较强(残余变形小),在较大非线性位移下试件破坏较少。文中分析了加固与未加固试件的恢复力特性、延性、耗能等抗震性能与试验参数的关系,为其今后在地震地区的施工和设计提出一个经济、合理的建议。

Large-Scale Synthesis of Porous Bi2O3 with Oxygen Vacancies for Efficient Photodegradation of Methylene Blue

Photocatalytic degradation of organic pollutants has become a hot research topic because of its low energy consumption and environmental-friendly characteristics.Bismuth oxide(Bi2O3)nanocrystals with a bandgap ranging from 2.0 eV to 2.8 eV have attracted increasing attention due to high activity of photodegradation of organic pollutants by utilizing visible light.Though several methods have been developed to prepare Bi2O3-based semiconductor materials over recent years,it is still difficult to prepare highly active Bi2O3 catalysts in large scale with a simple method.Therefore,developing simple and feasible methods for the preparation of Bi2O3 nanocrystals in large scale is important for the potential applications in industrial wastewater treatment.In this work,we successfully prepared porous Bi2O3 in large scale via etching commercial Bi Sn powders,followed by thermal treatment with air.The acquired porous Bi2O3 exhibited excellent activity and stability in photocatalytic degradation of methylene blue.Further investigation of the mechanism witnessed that the suitable band structure of porous Bi2O3 allowed the generation of reactive oxygen species,such as O2^-·and·OH,which effectively degraded MB.

Adsorption of octanohydroxamic acid at fluorite surface in presence of calcite species

The surface properties of fluorite are often affected by dissolved gangue species(e.g.,calcite)during the flotation process.Microflotation testing with and without the addition of calcite supernatant was conducted using octanohydroxamic acid(OHA)as the collector.The results revealed that dissolved calcite species significantly affected the flotation behavior of fluorite.Fourier transform infrared spectra confirmed that the decrease in flotation recovery was linked to lower OHA adsorption.Solution chemistry analysis indicated that CaCO_(3) and Ca^(2+)from the calcite supernatant were the most favorably adsorbed species,and X-ray photoelectron spectroscopy analysis confirmed the surface adsorption of calcite species.Density functional theory simulations provided a detailed analysis of the multidentate adsorption configuration of OHA,which was the most favorable for adsorption on the fluorite surface.The adsorption energy calculation showed that the calcite dissolved species were more stably adsorbed on the fluorite surface than OHA.The pre-adsorption of calcite dissolved species hindered the adsorption of OHA due to electrostatic repulsion.

Interfacial-interaction-induced fabrication of biomass-derived porous carbon with enhanced intrinsic active sites

Carbon catalysis is an attractive metal-free catalytic transformation,and its performance is significantly dependent on the number of accessible active sites.However,owing to the inherent stability of the C-C linkage,only limited active sites at the edge defects of the basal plane can be obtained even after a harsh oxidation treatment.In this study,the concept of interfacial interactions was adopted to propose an efficient strategy to develop highly active carbon catalysts.The alumina/carbon interface formed in situ acted as a cradle for the generation of oxygen-containing functional groups.In the absence of oxidation treatment,the concentration of oxygen-containing functional groups and the specific surface area can reach 1.27 mmol·g^(-1) and 2340 m^(2)·g^(-1),respectively,which are significantly higher than those of carbon prepared by traditional hard template methods.This active carbon shows a significant enhancement in catalytic performance in the oxidative coupling of amine to imine,about 22-fold higher than that of a well-known graphite oxide catalyst.Such interfacial interaction strategies are based on sustainable carbon sources and can effectively tune the porous structure of carbon in the micro-and meso-ranges.This conceptual finding offers new opportunities for the development of high-performance carbon-based metal-free catalysts.

Synthesis,Characterization and DNA-Binding Studies of [Ru(bpy)_(2)(PyIP)]^(2+) and [Ru(dmb)_(2)(PyIP)]^(2+)

Two novel polypyridyl{PylP=2-(pyren-1-yl)-lH-imidazo[4,5-f][1,10]phenanthroline,bpy=2,2′-bipyridine,dmb=4,4′-dimethyl-2,2′-bipyridine}ruthenium(Ⅱ)complexes[Ru(bpy)_(2)(PyIP)]^(2+)(1)and[Ru(dmb)_(2)(PyIP)]^(2+)(2)have been synthesized and characterized by elemental analysis,ES-MS and a H NMR spectroscopy.The DNA-binding of these complexes were investigated by spectroscopic methods and viscosity measurements.The experimental results indicate that both complexes 1 and 2 bind to calf thymus DNA in classical intercalation mode,and however,complex 1 intercalated more strongly than complex 2,due to the different ancillary ligands.

Improving electrochemical performance of Ni-rich layered oxide cathodes via one-step dual modification strategy

A one-step overall strategy from surface to bulk was proposed to simultaneously synthesize the Nb-doped and LiNbO_(3)-coated LiNi_(0.83)Co_(0.12)Mn_(0.05)O_(2) cathode materials.The incorporation of LiNbO_(3) coating can regulate the interface and facilitate the diffusion of Li-ions.Simultaneously,the stronger Nb—O bond can effectively suppress Li^(+)/Ni^(2+) cation mixing and strengthen the stability of crystal structure,which helps to mitigate the anisotropic variations of lattice parameters during Li^(+) de/intercalation.The results showed that the dual-modified materials exhibited good structural stability and distinguished electrochemical performance.The optimal NCM-Nb2 sample showed an excellent capacity retention of 90.78%after 100 cycles at 1C rate between 2.7 and 4.3 V,while only 67.90%for the pristine one.Meanwhile,it displayed a superior rate capability of 149.1 mA·h/g at the 10C rate.These results highlight the feasibility of one-step dual modification strategy to synchronously improve the electrochemical performance of Ni-rich layered oxide cathodes.

FRP嵌入式加固法（NSM）研究与应用现状

FRP嵌入式加固法是近年来国外兴起的-种新兴的结构加固形式.介绍了FRP嵌入式加固法的特点、研究以及应用现状,并提出了现阶段需要继续深入的一些问题.

福州数字中国会展中心楼盖舒适度分析及振动控制

采用调谐质量消能器对福州数字中国会展中心的大跨度楼盖进行了舒适度分析和减振设计,对结构采用调谐质量消能器进行减振设计前后的舒适度进行对比分析,结果表明:减振前结构在人行荷载激励下大跨度楼盖不满足舒适度要求,采用调谐质量消能器后振动得到有效控制,满足舒适度要求。从而证明了调谐质量消能器能有效改善大跨度楼盖的舒适度,且具有良好的经济性与适用性,可在类似工程结构中进行推广和应用。

Preparation and properties of porous ceramics from spodumene flotation tailings by low-temperature sintering

Porous ceramics were prepared with spodumene flotation talings(SFT),kaolin and low-melting point glass(LPG)powder,whose pores were formed by the chemical reaction of hydrogen peroxide(H_(2)O_(2)).LPG was used to reduce the sintering temperature of porous ceramics and kaolin was used to realize the adsorption to methylene blue(MB)of porous ceramics.The average flexural strength,compressive strength,apparent porosity,water absorption and maximum MB adsorption capacity were 5.60 MPa,4.66 MPa,52.27%,44.32%and 0.7 mg/g,respectively.Moreover,the results of orthogonal experiments present that the sintering temperature and the dosage of H_(2)O_(2)had great influence on the mechanical properties and apparent porosity of porous ceramics,respectively.The main reason for the improvement of mechanical properties of porous ceramics was that LPG gradually became soft with increasing the sintering temperature,which made the mineral particles adhere to each other closely.Kaolinite was not completely converted into metakaolin at 550℃,which might be the main reason why porous ceramics had adsorption properties.

Amine formylation with CO2 and H2 catalyzed by heterogeneous Pd/PAL catalyst

For the first time, Pd supported on natural palygorskite was developed for amine formylation with CO2 and H2. Both secondary and primary amines with diverse structures could be converted into the desired formamides at < 100 °C, and good to excellent yields were obtained.

Effect of the degree of dispersion of Pt over MgAl_2O_4 on the catalytic hydrogenation of benzaldehyde

One of the central tasks in the field of heterogeneous catalysis is to establish structure‐function relationships for these catalysts,especially for precious metals dispersed on the sub‐nanometer scale.Here,we report the preparation of MgAl2O4‐supported Pt nanoparticles,amorphous aggregates and single atoms,and evaluate their ability to catalyze the hydrogenation of benzaldehyde.The Pt species were characterized by N2adsorption,X‐ray diffraction(XRD),aberration‐corrected transmission electron microscopy(ACTEM),CO chemisorption and in situ Fourier transform infrared spectroscopy of the chemisorbed CO,as well as by inductively coupled plasma atomic emission spectroscopy.They existed as isolated or neighboring single atoms on the MgAl2O4support,and formed amorphous Pt aggregates and then nanocrystallites with increased Pt loading.On the MgAl2O4support,single Pt atoms were highly active in the selective catalytic hydrogenation of benzaldehyde to benzyl alcohol.The terrace atoms of the Pt particles were more active but less selective;this was presumably due to their ability to form bridged carbonyl adsorbates.The MgAl2O4‐supported single‐atom Pt catalyst is a novel catalyst with a high precious atom efficiency and excellent catalytic hydrogenation ability and selectivity.

Photocatalytic Performance and Mechanism Study of High Specific Area TiO_(2) Combined with g-C_(3)N_(4)

g-C_(3)N_(4) coupled with high specific area TiO_(2)(HSA-TiO_(2))composite was prepared by a simple solvothermal method,which was easy to operate with low energy consumption.Degradation of methyl orange test results showed that HSA-TiO_(2) effectively improved the photocatalytic activity effectively.Photoelectrochemical test results indicated that the separation of photo-generated carriers and the charge carrier migration speed of TiO_(2) were improved after combination with g-C_(3)N_(4).g-C3N4/HSA-TiO_(2) showed strong photocatalytic ability.The degree of degradation of methyl orange by 6%-g-C_(3)N_(4)/HSA-TiO_(2) could reach up to 92.44%.Furthermore,it revealed good cycle performance.The photocatalytic mechanism of g-C_(3)N_(4)/HSA-TiO_(2) was proposed.

Near-Field Scattering Enhancement of Perylene Based Aggregates for Random Lasing

Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide(DPP) which possesses POSS as scatteres experimentally performs strong NFSE, which confirms the physical simulation results. Moreover, coherent random laser is triggered from the DPP aggregates in carbon disulfide. It is the NFSE of POSS NPs connected to both ends of DPP through covalent bonds and the NFSE of their aggregation thanks to DPP’s aggregation that is responsible for the coherent random laser. So, this work develops a method to improve weak scattering of system through construction of molecules, and opens a road to a variety of novel interdisciplinary investigations, involving molecular designing for disordered photonics.

剪力墙端柱外粘型钢在某住院楼改造中的应用

柱外粘型钢加固对改善柱的轴压比有较好的作用,并且对加固后的柱刚度提高较小,较符合计算中的假定,介绍了该种加固形式在实际工程中的运用.