View factors for surface zones

Methods of calculating view factors with different surface configurations are compared. A simple approach is proposed for estimating the error in calculating the view factors. An algorithm is formulated for selection of the method and the number of points of integration prior to the calculation. The algorithm significantly reduces the computation time by minimizing the number of integration points required, without loss of precision.     

Adiabatic slice-selective excitation for surface coils

A novel RF pulse designed to perform a diabatic slice-selective excitation for surface coils (ASSESS) is proposed in which Bzero gradient is modulated in concert with RF frequency modulation. Within the selected slice, the principles of BIR4 pulses are employed to obtain well-defined, pure-phase and self-refocused spin rotation of arbitrary flip angles despite the presence of high B1 inhomogeneity produced by surface coils. Outside the slice, advantage is taken of the B1 field to dephase equilibrium magnetization to achieve slice selection or outer-volume suppression. This scheme should be useful for many localization techniques. Quaternion analysis of the overall propagator of the proposed pulse and numerical simulations using Bloch equations are performed. The pulse is tested experimentally on a phantom sample.     

Dry-process surface modification for titanium dental implants

Because dental implants contact many different tissues, the implant material must have optimum surface compatibility with the host bone tissue, subepithelial connective tissue, and epithelial tissue. In addition, dental implant surfaces exposed to the oral cavity must remain plaque-free. Such materials can be created under well-controlled conditions by modifying the surfaces of metals that contact those tissues. “Tissue-compatible implants,” which are compatible with all host tissues, must integrate with bone tissue, easily form hemidesmosomes, and prevent bacterial adhesion. This research was aimed at developing such tissue-compatible implants by modifying titanium surfaces using a dry process for closely adhering to the titanium substrate and ensuring good wear resistance. The process includes ion beam dynamic mixing (thin calcium phosphates), ion implantation (Ca⁺, N⁺, F⁺), titania spraying, ion plating (TiN, alumina), and ion beam mixing (Ag, Sn, Zn, Pt) with Ar⁺. At the bone tissue/implant interface, a thin calcium phosphate coating and rapid heating with infrared radiation were effective in controlling the dissolution without cracking the coating. This thin calcium phosphate coating may directly promote osteogenisis, but it may also enable immobilization of functional proteins or drugs. At the oral fluid/implant interface, an alumina coating and F⁺ implantation were responsible for inhibiting the adhesion of microbial plaque. In conclusion, dry-process surface modification is useful in controlling the physicochemical nature of surfaces, including the surface energy and the surface electrical charge, and in developing tissue-compatible implants.     

镀锡板表面分析实验样品的前处理方法分析

通过X射线光电子能谱（XPS）分析手段,对经不同清洗液超声清洗并气枪吹干后的镀锡板样品表面元素组成进行了表征,发现经过这些传统的测试前处理过程,样品表面均会留下一个主要由C、O及可能存在的H为主要成分组成的薄膜。该薄膜在常温下的大气环境中表现稳定,但在轻微加热后可完全脱附。由此总结出对镀锡板样品,使用如下方法,即酒精超声清洗并冷风吹干后,进样到真空室里,等待进行分析前,再将样品微微加热使保护膜脱附,可以得到洁净的待分析表面,满足表面分析的需要。     

Adaptive-filter technology for detecting steel-strip surface roughness

To address the shortcomings of traditional filtering methods that utilize the scattering method for the online detection of strip surface roughness and to improve the accuracy of the identification of strip surface roughness,in this paper,a regression-smoothing adaptive-filtering method was investigated for use in the online detection of surface roughness in the cold-rolled strip. The results show that by the use of robust locally weighted regression to perform noise-reduction preprocessing of the initial parameters in the online detection of surface roughness,followed by the establishment of a kernel function,the regression-smoothing adaptive-filtering method can update the weight based on the relative positions of historical and current data. When the changes in neighboring data exceed the established threshold value of 0. 75 μm,the width of the smoothing window is automatically reduced,thereby realizing adaptive variable-step regression-smoothing filtering of online roughness detection data. By the use of this regression-smoothing adaptive-filtering method,the accuracy of detecting the surface roughness of a cold-rolled strip can be improved and the requirements of downstream users better satisfied.     

Phase-polarisation contrast for surface plasmon resonance biosensors

A technique of phase-polarisation contrast (PPC) for the enhancement of the contrast of a surface plasmon resonance (SPR) intensity profile is proposed and experimentally realised. The technique exploits the peculiarities of light phase and polarisation behaviour under SPR. It applies to non-optimum SPR coupling conditions and enables one to lower the resonant minimum of reflected intensity nearly to zero, and hence to increase substantially the ratio of the intensity from the resonance to that at the minimum. We observed the contrast enhancement by more than one order of magnitude when we applied the PPC scheme. The PPC can be efficiently employed in commercial SPR sensors, as it significantly reduces restrictions on allowable parameters of SPR-supporting metal films and biomolecular layers immobilised on them, facilitates SPR observation, and increases the accuracy of SPR shift measurements.     

轴承钢端面碎裂原因分析与改进

通过对轴承钢端面碎裂进行分析,认为钢材端部的异常组织是导致矫直后端部碎裂的主要原因。由于轴承钢采用摩擦锯进行定尺锯切,使端部受热,并且端部组织发生了组织转变而产生碎裂。针对分析结果,采取了使用进口锯片锯切的补救措施,解决了钢材矫直过程中的碎裂问题。     

Wipe testing for surface contamination by tritiated compounds

This study investigated the performance of the wipe test in determining contamination from tritiated triolein or thymidine on various surfaces. Filter papers were saturated with water, methanol, petroleum ether, ethyl acetate or maintained dry, and wipes were taken from lead, stainless steel, polyurethane, wood, painted lead, treated floor tile, Formica, or bench paper that were spotted with either 3H-thymidine or 3H-triolein. The recovery of contamination using the dry wipe test averaged 3% for all surfaces. Recoveries using wet wipes were directly related to the solubility of the tritiated compounds in the wipe solution and the physical nature of the wipe surface.     

Rapid three-dimensional measuring system for facial surface structure

A noncontact three-dimensional measuring system (liquid crystal range finder system) is described. Three-dimensional facial surface data (more than 30,000 points) could be obtained in 1 second, and the resolution was approximately 0.4 mm. The reliability and repeatability of the results were validated with a calibrating apparatus and a highly accurate contact-type three-dimensional digitizer. Consequently, the average of the measurement errors on a facial plaster model was 0.3 mm. Repeatability in measuring human faces was approximately 0.3 mm. Therefore, the total error in measuring human faces was approximately 0.5 mm. Because of the shortness of measuring time, this system was capable of scanning faces of infants without the need for sedation. The output of the liquid crystal range finder was demonstrated on an infant with cleft lip. The surface points improved by cheiloplasty, and the residual deformities were observed clearly. This system was thought to be the most suitable apparatus for measuring faces of infants (especially infants with cleft lip) and enabled us to analyze facial surface structure both qualitatively and quantitatively.