Analysis of layer splitting in x and z-cut KTiOPO4 implanted by H+ ions

H⁺ ions with various fluences are implanted into x and z-cut KTP crystals to achieve KTP film. Post-implantation annealing under different temperature is imposed on the samples to induce layer splitting and surface morphology modification. Layer exfoliation is observed in freestanding z-cut samples. Layer splitting is obtained using bonding method in x-cut sample implanted with 117 keV H⁺ ions at ion fluence of 6 × 10¹⁶ ions/cm². Optical microscopy, scanning electron microscope and atomic force microscopy are used to observe splitting phenomenon. Rutherford backscattering spectroscopy/channeling method is employed to measure lattice damage and to investigate the relationship between implantation-induced defects and layer splitting.     

Controlled chemical modification of the internal surface of photonic crystal fibers for application as biosensitive elements

Photonic crystal fibers (PCF) are one of the most promising materials for creation of constructive elements for bio-, drug and contaminant sensing based on unique optical properties of the PCF as effective nanosized optical signal collectors. In order to provide efficient and controllable binding of biomolecules, the internal surface of glass hollow core photonic crystal fibers (HC-PCF) has been chemically modified with silanol groups and functionalized with (3-aminopropyl) triethoxysilane (APTES). The shift of local maxima in the HC-PCF transmission spectrum has been selected as a signal for estimating the amount of silanol groups on the HC-PCF inner surface. The relationship between amount of silanol groups on the HC-PCF inner surface and efficiency of following APTES functionalization has been evaluated. Covalent binding of horseradish peroxidase (chosen as a model protein) on functionalized PCF inner surface has been performed successively, thus verifying the possibility of creating a biosensitive element.     

The rim zone of cement-based materials – Barrier or fast lane for chemical degradation?

Sophisticated evaluation models for the long-term stability of cement-based systems demand a precise knowledge of the mechanisms of deterioration reactions, particularly respecting a permanent exposure to aqueous environments. Commonly, insights into these mechanisms are deduced from long-term investigations. However, these chemical reactions start immediately after exposure to aggressive environments causing rapid changes of composition and structure. Consequently, properties of its rim zone change, which affects transport processes in aqueous solutions. In laboratory experiments, the influence of these surface processes on the stability of cement-based materials exposed to different chloride solutions was studied as a function of time and temperature. Analysis of compositional and structural changes beneath the surface reveal the role of crystalline covering layers for chemical resistance. Such layers are often described as protective barriers. However, these processes in the rim zone can accelerate chemical degradation and subsequently reduce the resilience of the cement-based materials to aggressive aqueous environments.     

志高小区变压器结构噪声分析与控制

为解决志高小区变压器噪声扰民问题,通过对该小区地下室干式变压器分布的研究,并结合对变压器噪声传播机理的分析,得出由变压器振动引起的结构噪声是扰民的主要原因。采取安装隔振装置等隔振措施,有效地降低了变压器噪声对居民的影响,并通过对居民室及变压器隔振前后的振动加速度进行测量,同一测点振动级降低均在10 d B以上,同一测点的加速度值降低60%以上,基本解决了由变压器结构噪声引起的噪声扰民问题。     

全孔蓄水法在高温火区爆破中的应用

针对高温炮孔因裂隙多导致蓄不住水的情况,将内层带有不透水材料的套管快速下放到炮孔并在短时间内注满水,在套管中装有模拟药卷并采用热电偶测量套管中的水温变化。结果表明:全孔蓄水可使工业炸药与起爆器材长时间保持在最高温度不超过水浴温度的环境中,因此能大幅延长高温火区装药施工时间。探索出高温火区的全孔蓄水爆破方法,并通过爆区规模试验,效果良好,该方法能保证施工安全,同时基本解决高温火区较大规模爆破的问题。     

超声冲击诱发表面纳米化及其对表面完整性的影响

采用不同超声冲击参数处理SMA490BW钢,研究了冲击后试样在低、高倍下的微观组织特征、残余应力及硬度分布等表面完整性能的变化。实验结果表明,经过超声冲击表面处理后,样品表面层晶粒细化为纳米晶,平均晶粒尺寸约为30nm;并在试样表层引入残余压应力,数值最大约为255.5MPa;超声冲击对SMA490BW钢表面能够起到明显的强化作用,与未经处理的试样相比,处理后试样表面硬度最大提高了约66.7%。超声冲击强化处理改善SMA490BW钢的表面完整性的效果与冲击电流、冲击时间之间的关系不遵循单调变化规律,超声冲击参数为20min/1.5A时,试样具有较好的表面完整性,冲击影响层深度约为320μm。     

异型截面楼房定向爆破的关键技术和应用

为解决高宽比小、截面惯性矩大的异型截面楼房定向爆破的技术难题,根据楼房倾倒瞬间的受力分析,提出了支撑区宽度和定向切口高度的确定方法,认为定向大切口和使楼房定向倾倒转动铰前移的宽支撑区是满足楼房倾覆力矩和足够支撑力的关键技术。并介绍了在一栋双Y型截面的14层框架-剪力墙楼房的爆破实施案例,应用分割和整体定向爆破方法把该楼房分割为一栋矩形截面、两栋V型截面楼房,实现了在同一工程中,矩形截面楼房和相同结构的两栋V型截面楼房向结构相反方向定向爆破的技术参数和爆破效果的相互对比。结果表明:宽支撑区可有效防止楼房后坐,相对增大了楼房的高宽比以及定向切口角度。     

冷拉减面率对C形环用Inconel X-750丝材组织性能的影响

文章通过冷拉拔加工制备减面率为0%、30%、60%的Inconel X-750丝材,分别在650℃、730℃、810℃下时效处理16h,研究冷拉减面率对X-750合金组织性能的影响,特别是减面率对γ′相形状、分布、数量及尺寸的影响。经定量分析,增大冷拉减面率除了有细化晶粒的作用外,还能一定程度地增加γ′相析出的颗粒数量及体积分数,减小γ′相尺寸,进一步加强沉淀强化的作用。时效温度对X-750丝材的晶粒尺寸没有明显影响,对γ′相的数量、尺寸及形状影响较大。采用730℃时效处理16h的标准工艺制备的X-750丝材,经加工为弹簧后制造成金属C形密封环,其回弹量及泄漏率均满足要求,实验条件下密封性能良好。     

Surface energy-mediated fibronectin adsorption and osteoblast responses on nanostructured diamond

Nanostructured diamond have potential applications in many biomedical related fields and demonstrated extraordinary capacity to influence cellular responses. Studying the surface property of nanodiamond and its influence to protein adsorption and subsequent cellular responses along with the mechanism behind such capacity becomes more important. Here the role of surface energy associated with nanostructured diamond in modulating fibronectin and osteoblast(OB, bone forming cells) responses was investigated. Nanocrystalline diamond(NCD) and submicron crystalline diamond(SMCD) films with controllable surface energy were prepared by microwave-enhanced plasma chemical vapor deposition(MPCVD) techniques. Fibronectin adsorption on the diamond films with varied surface energy values was measured via the enzyme-linked immunosorbent assay(ELISA) and the relationship between the surface energy and fibronectin adsorption was studied. The result indicated that fibronectin adsorption on nanostructured surfaces was closely related to both surface energy and material microstructures. The spreading and migration of OB aggregates(each containing 30–50 cells) on the NCD with varied surface energy values were also studied. The result indicates a correlation between the cell spreading and migration on nanodiamond and the surface energy of nanostructured surface.     

Surface integrity of Inconel 718 by hybrid selective laser melting and milling

ABSTRACT

While selective laser melting (SLM) offers design freedom of metal parts with much less material consumption, there exist several limitations, including high surface roughness, low-dimensional accuracy, and high tensile residual stresses. To make functional parts with high form accuracy and superior surface integrity, an as-SLM part needs finishing to remove the deposited surface material. The integration of machining and SLM creates a hybrid manufacturing route to overcome the inherited limitations of SLM. However, little study has been done to characterise surface integrity of an as-SLM part followed by machining (e.g. hybrid SLM-milling). In this paper, surface, integrity including surface roughness, microstructure, and microhardness, have been characterised for IN718 samples processed by the hybrid process. It has been found that microhardness varies with the scan direction and the use of coolant in the subsequent milling, and surface integrity can be significantly improved by the hybrid SLM-milling route.