Seeing is believing? When scanning electron microscopy (SEM) meets clinical dentistry: The replica technique.

In restorative dentistry, the in situ replication of intra‐oral situations, is based on a non‐invasive and non‐destructive scanning electron microscopy (SEM) evaluation method. The technique is suitable for investigation restorative materials and dental hard‐ and soft‐tissues, and its interfaces. Surface characteristics, integrity of interfaces (margins), or fracture analysis (chipping, cracks, etc.) with reliable resolution and under high magnification (from ×50 to ×5,000). Overall the current study aims to share detailed and reproducible information about the replica technique. Specific goals are: (a) to describe detailed each step involved in producing a replica of an intra‐oral situation, (b) to validate an integrated workflow based on a rational sequence from visual examination, to macrophotography and SEM analysis using the replica technique; (c) to present three clinical cases documented using the technique. A compilation of three clinical situations/cases were analyzed here by means the replica technique showing a wide range of possibilities that can be reached and explored with the described technique. This guidance document will contribute to a more accurate use of the replica technique and help researchers and clinicians to understand and identify issues related to restorative procedures under high magnification.     

Comprehensive performance evaluation of distributed and dynamic mobility routing strategy

In this paper, we conduct a comprehensive performance study of distributed and dynamic mobility management (DDMM). DDMM presents a new architectural paradigm for a sustainable mobile networking against an ever-increasing amount of Internet data traffic, providing IP mobility management with distributed deployment of mobility anchors and dynamic activation when mobility is needed. Such a distributed mobility management concept is generally and intuitively accepted in terms of effective distribution of mobile traffic when compared with centralized mobility management (CMM) approaches. Nevertheless, the routing strategy of DDMM has not yet been properly examined through performance studies, and especially the impact of potential mobility routing strategies on the user plane is an open question. We perform a mathematical analysis of DDMM and present numerical results aiming to identify in which conditions, by which factors, and how much, DDMM improves mobility performance. For comparison, Mobile IPv6, Proxy Mobile IPv6 (PMIPv6), and PMIPv6 localized routing (PMIPv6-LR) were considered as representative IP mobility protocols following CMM approaches. Analytical results demonstrate that DDMM generally achieves higher performance when compared with CMM-based protocols in terms of packet delivery cost, tunneling overhead, and throughput, but specific performance varies in function of multiple input parameters.     

探讨加强质量监督管理提高电网安全水平

电网的安全水平主要取决于其使用产品的质量是否过关。如果产品的质量较好，则能建造出优质的电网，电网的安全水平便会随之提高。因此，应加强对产品质量的监督管理，从而提高电网的安全水平。我们可建立质量监督管理系统，及时抽检出质量不过关的产品，从而消除电网运行过程中潜在的安全隐患。     

汽车总装线上远程激光焊接能量评估

通过分析激光源的类型和结构,建立参数数据库,并结合机器人运动的动力学分析,本研究提出了汽车总装线上远程激光焊接(RLW)的能量评估模型。通过对简单焊件进行焊接实验,将传统激光焊接和远程激光焊接进行了对比,结果发现,焊接过程中机器人运动能量逐渐减少,而激光能量逐渐增加。处理时间和激光功率是影响远程焊接能源效率的主要因素。     

Damage mapping with a degrading elastic modulus using piezospectroscopic coatings

The development of piezospectroscopic (PS) composites has enabled the creation of a non-destructive evaluation (NDE) technique which integrates piezospectroscopy, digital image correlation (DIC) and analytical multi-scale mechanics to map the elastic modulus of a coated material. The measured elastic modulus was represented as a normal distribution with a mean value (32.2 GPa) which is within 8% of the conventionally recorded modulus (35 GPa). Damage mechanics are applied to map elastic degradation in situ mechanical loading with an average uncertainty (~10 GPa) that was sufficient in observing subsurface, progressive damage patterns which are unique to the coated material.     

俄罗斯原油性质变化趋势及加工设想

原油的特性对制定合理的加工方案起着决定性作用,所以,必须详细了解原油的性质,掌握原油的变化趋势,并随时跟踪炼油技术进步及市场波动趋势,提出优化的原油加工规划设想。通过对俄罗斯原油(简称俄油)性质的分析,减压渣油采用渣油加氢-催化裂化工艺技术进行生产加工,虽然投资较大,但因其可生产高附加值的汽油、丙烯等产品,因此具有很高的经济效益,为企业的持续发展奠定扎实的基础。     

Analytical solution for interaction of an arbitrary frequency curved rectangular inducer with a transverse ring shaped groove surrounding a long conductive cylinder

Field distributions around a transverse flaw surrounding a conductive cylinder which is excited by a three-dimensional inducer at arbitrary frequency are presented analytically. The solution is obtained by developing a two-dimensional Fourier series model and using Bessel functions in the third dimension. The metal is assumed as a lossy material and all possible field components in the conductor are expanded. After applying the mode-matching technique, a linear system of AX=B is solved to obtain the unknown coefficients. The accuracy of the proposed modeling technique is confirmed by comparing our results with those obtained by CST finite integration code.     

Evaluation of the intergranular corrosion in austenitic stainless steel using collinear wave mixing method

Failures due to intergranular corrosion in components of austenitic stainless steel have always been a tough problem in engineering practice. In this paper, the collinear wave mixing was investigated to evaluate the intergranular corrosion in austenitic stainless steel. An acoustic nonlinearity parameter related to the bispectrum, the propagation distance and the amplitudes of fundamental waves in measured signal is proposed. Nonlinear acoustic measurements were conducted on four tubes with different degree of intergranular corrosion. The experimental results demonstrated that the proposed acoustic nonlinearity parameter is sensitive to intergranular corrosion in samples, and is well correlated with the degree of damage.     

Design and characterization of compact proton exchange membrane water electrolyzer for component evaluation test

In this study, we designed and developed a compact electrolyzer for the evaluation of components in proton exchange membrane (PEM) water electrolysis. First, this electrolyzer features a precise pressure-control system that controls the active electrode area and facilitates setting the desired clamping pressure. This mechanism makes it possible to optimize the electrolyzer performance. Second, it has two reference electrodes that are connected on the faces of the active electrode area of the anode and the cathode on the PEM. The polarizations at the anode and the cathode, the membrane resistivity, and the porous transport layer (PTL) overpotential were measured. The details of the design are described, and the electrochemical performance was measured. The optimized clamping pressure for this electrolyzer component was obtained as the specific value. A new measurement method was developed for estimating polarizations at the anode and the cathode, membrane resistance, and PTL overpotential using two reference electrodes.