合金层白点的产生及其对镀锡板耐蚀性的影响

脱去镀铬板的自由锡层后，在锡铁合金层的表面目视发现了大量沿轧制方向伸展的白点，并且合金层的耐蚀性奠着白点数量与覆盖面积的增加而下降。采用扫描电镜(SEM)观察了合金层的形貌，用能谱(EDS)分析了白点与非白点处的成分，结果发现：白点处的合金层存在空洞，且铁的含量高于非白点处的含量。将表面带有大量白点的合金层进行14d的湿热实验后发现，在白点的边缘以及小白点处容易生锈，采用原子力显微镜(AFM)观察了锈点处的形貌，并解释了发生这一现象的原因。通过实验室模拟和现场数据的分析，找出了合金层表面白点产生的原因。     

Corrosion protection performance of High Performance Fiber Reinforced Cement Composites as a repair material

This paper regards the corrosion protection performance of High Performance Fiber Reinforced Cement Composites (HPFRCC) as a repair material. For the purpose of improving workability, the volumetric fiber content in HPFRCC was decreased from its usual rate of 1.5% to as low as 0.75%. The applicability of HPFRCC as a repair material for preventing steel corrosion was investigated using specimens that simulated either surface coating repair or patch repair. The results can be summarized as follows: Patch repair with HPFRCC to depths beyond the backside of the reinforcement effectively suppressed chloride penetration and prevented reinforcement corrosion, whereas surface coating with HPFRCC could not prevent corrosion of the steel in the RC substrate. As long as the fiber content is set so that only fine cracks are formed under service conditions, differences in fiber content did not affect the corrosion preventing performance of HPFRCC as a repair material.     

铅与光照对镀锌层黑变的影响

在硫酸盐镀液中所得的含铅与不含铅的镀锌试片，经铬酸盐钝化后，通过湿热试验（ＨＣＴ）进行了黑变培养，采用试片的表面明度差来表征黑变的程度，考察了铅和光照对其黑变速率的影响，发现镀液中铅离子的存在使黑变反应的活化能Ｅａ从３４ｋＪ／ｍｏｌ左右降低到２１ｋＪ／ｍｏｌ左右，从而加速了黑变反应。光照虽然使Ｅａ降低了０．５ｋＪ／ｍｏｌ，但同时较大幅度地降低了指前因子Ａ的值，总的作用结果是抑制了黑变的反应     

Changes in bite force and occlusal contacts in patients treated for mandibular prognathism by orthognathic surgery

PURPOSE: The purpose of this study was to evaluate changes in bite force and occlusal contacts before and after orthognathic surgery in patients with mandibular prognathism and to compare the findings with those in controls with normal occlusion. PATIENTS AND METHODS: Bite force and occlusal contacts were analyzed in 23 (7 male and 16 female) patients with mandibular prognathism before and after sagittal split ramus osteotomy, and in 20 (10 male and 10 female) controls with normal occlusion. The bite force and occlusal contacts were simultaneously measured by a computerized occlusal analysis system, the T-Scan system, immediately before surgery, and at 6 weeks, 3 months, 6 months, and 1 year postoperatively. RESULTS: Both the bite force and occlusal contacts in the patients were significantly less than those in the controls before surgery. Although both the bite force and occlusal contacts in the patients were improved by the orthognathic surgery, neither approached the level in the controls within 1 year. Bite force was correlated with the number of occlusal contacts in both patient and control groups. CONCLUSION: The postoperative masticatory function does not reach control levels even 1 year after the orthognathic surgery for mandibular prognathism. Therefore, further adjustment of the occlusion should be considered before the end of treatment.     

Suppression of luteinizing hormone in castrated women by the administration of human chorionic gonadotropin

The suppressive effect of human chorionic gonadotropin (hCG) on luteinizing hormone (LH) and/or LH-beta was studied by specific LH-beta radioimmunoassay following hCG administration. Eight castrated women were each administered 10,000 IU of hCG in a single intramuscular injection and five women in the control group were injected with saline. The serum level of hCG increased after the injection, reaching 217.6 mIU/ml after 8 h. There was a significant suppression of LH levels as compared to those of the control group and the pre-injection levels: 68.2% 1 h after injection, 64.7% after 2h, 65.5% after 4 h, 77.0% after 8 h, 78.6% after 12 h, and 78.2% after 24 h. There was no significant suppression of the follicle-stimulating hormone (FSH) as compared to the preinjection and control values. Serum concentration of estradiol1 was not detectable either before or after the hCG injection. We conclude that hCG has a suppressive effect on LH and/or LH-beta secretion not mediated by estradiol.     

Preparation of spherical wax matrices of sulfamethoxazole by wet spherical agglomeration technique using a CMSMPR agglomerator

Spherical wax matrices of sulfamethoxazole were prepared by a wet spherical agglomeration technique using a model continuous mixed suspension mixed product removal (CMSMPR) agglomerator to develop a practical continuous operation system. The average diameter of products increased at the initial stage of operation until reaching a maximum at 5 to 7 minutes elapsed after starting. This maximum point roughly corresponded to a half of average retention time. Thereafter the particle size decreased gradually and reached the equilibrium state. The average size of products obtained at steady state decreased on decreasing the feeding rate of bridging liquid, but increased on decreasing the agitation speed and the feeding rate of aqueous suspension. The rate of agglomeration was analysed using the concept of population balance proposed by Randolph and Sikdar. The agglomeration rate increased with increase of particle size for sizes above 200 – 300 μm. For sizes below 200 μm, the agglomeration rate was almost independent of particle size.     

Suppression of nitridation of yttria-doped zirconia during flash sintering

The effect of direct current (DC) and alternating current (AC) on nitridation of 3 mol% Y₂O₃-doped ZrO₂ (3YSZ) after keeping in a flash state for 1 hour was investigated. The inside of the DC-flashed compact was confirmed to exhibit blacking. Scanning transmission electron microscopy, electron energy loss spectroscopy, and X-ray diffraction analysis revealed that zirconium nitrides formed in the blackened area. In contrast, a uniformly densified compact without blackening was obtained by AC fields. No zirconium nitrides formed in the compacts exposed to AC fields even when the flash state was maintained for 1 hour. Therefore, AC fields are effective to suppress nitridation of 3YSZ during flash sintering.     

Electrochemical behavior and electrodeposition of dysprosium in ionic liquids based on phosphonium cations

The electrochemical behavior and the electrodeposition of dysprosium (Dy) in phosphonium-cation-based ionic liquid were investigated in this study. A new group of the room-temperature ionic liquids (RTILs) based on phosphonium cations with bis(trifluoromethylsulfonyl)amide anions was applied as novel electrolytic solutions. The cyclic voltammetric measurements resulted in one step reduction of the trivalent dysprosium ion in phosphonium-cation-based ionic liquid. On the other hand, no anodic peak ascribed to the oxidation of dysprosium metal was observed in this electroanalytical study. The diffusion coefficient and the activation energy for diffusion of the trivalent Dy complex in IL were estimated using semi-integral analysis, because it is important to analyze the diffusion properties to recover Dy through electrowinning methods. The diffusion coefficient of Dy(III) which was calculated to be 2.0 × 10⁻¹² m² s⁻¹ at 25 °C, closed to that of the trivalent lanthanoid ion such as Eu(III) and Sm(III) in phosphonium-cation-based ionic liquid. In addition, the activation energy for diffusion was estimated to be 65 kJ mol⁻¹ (0.5 M) and 49 kJ mol⁻¹ (0.075 M). The estimated activation energy for diffusion was affected by the concentration of the electrolytic solution, since the RTILs had relatively strong electrostatic interactions between the metal cations and the solvent anions. Furthermore, the electrodeposition of Dy in phosphonium-cation-based IL was carried out using a two-electrode system constructed with a copper plate cathode and dysprosium metal anode. Energy dispersive X-ray analysis of electrodeposits showed a sharply peaked spectrum corresponding to the characteristic X-ray lines of Dy. In addition, the obtained Dy, with the exception of the surface layer, was confirmed to be in the metallic electronic state by X-ray photoelectron spectroscopy.     

Carbon nanotube loop arrays for low-operational power,high uniformity field emission with long-term stability

We present a rational field emitter array architecture composed of thin multi-walled carbon nanotube “loops” which simultaneously satisfies the important requirements for practical applications. We achieved low turn-on voltage (1.27 V/μm for 10 μA/cm² emission), high enhancement factor (2400), uniformity, and long-term emission stability exceeding 10,000 h at 1 mA/cm², where each of the values approaches or exceeds the highest reported values to date for field emission arrays.