Freeze drying of a porous Cu-Sn alloy with unidirectionally aligned pore channels was accomplished by using a composite powder of CuO-SnO2 and camphene. Camphene slurries with CuO-SnO2 content of 3, 5 and 10 vol% were prepared by mixing with a small amount of dispersant at 50˚C. Freezing of a slurry was done at -25˚C while the growth direction of the camphene was unidirectionally controlled. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green bodies were hydrogen-reduced at 650˚C and then were sintered at 650˚C and 750˚C for 1 h. XRD analysis revealed that the CuO-SnO2 powder was completely converted to Cu-Sn alloy without any reaction phases. The sintered samples showed large pores with an average size of above 100μm which were aligned parallel to the camphene growth direction. Also, the internal walls of the large pores had relatively small pores. The size of the large pores decreased with increasing CuO-SnO2 content due to the change of the degree of powder rearrangement in the slurry. The size of the small pores decreased with increase of the sintering temperature from 650˚C to 750˚C, while that of the large pores was unchanged. These results suggest that a porous alloy body with aligned large pores can be fabricated by a freeze-drying and hydrogen reduction process using oxide powders.

The object of this paper is to examine the noise generating mechanism at manufacturing process of metal material products. To accomplish the object; A noise generating mechanism of high noise machine, which is mounted in the small and medium size enterprise, was investigated. The measurement method of the noise for the machine by manufacturers were investigated. The noise at the 250 points of the manufacturing process machine in the 40 processes of the 3 factories, 3 business fields was measured. The database of the noise was built from the measurement data. The major sound sources and frequency range for the manufacturing process of metal material product machine was investigated.

This research presents a preparation method of dental components by metal injection molding process (MIM process) using titanium scrap. About 20 μm sized spherical titanium powders for MIM process were successfully prepared by a novel dehydrogenation and spheroidization method using in-situ radio frequency thermal plasma treatment. The effects of MIM process parameters on the mechanical and biological properties of dental components were investigated and the optimum condition was obtained. After sintering at 1250oC for 1 hour in vacuum, the hardness and the tensile strength of MIMed titanium components were 289 Hv and 584 MPa, respectively. Prepared titanium dental components were not cytotoxic and they showed a good cell proliferation property.

We measured the grain size and metallics elements (Li, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg, Pb, Fe and As) of surface sediments collected from 27 sampling sites in the Abalone aquaculture. The concentration range and average value of metallics elements were also below the sediment quality guidelines (TEL). As the pollution level was estimated by using enrichment factor (Ef) and index of geoaccumulation (Igeo), the enrichment factor (Ef) was about 1 for most of metallic elements were smaller than 1. However Arsenic (As) had highest value of 2.35. Index of geoaccumulation (Igeo) for the metallic elements (As, Pb and Mn) were ranged Igeo-class 0 (practically unpolluted) and most metallics elements (Li, V, Cr, Fe, Co, Ni, Cu, Zn, Cd, Hg and Fe) were ranged Igeo-class 0~2, indicating that the pollution levels of metallic elements should not be significant. It is necessary to keep monitoring pollution level in Abalone aquaculture to conserve the blue belt.

We investigated the characteristics of electroless plated Cu films on screen printed Ag/Anodized Al substrate. Cu plating was attempted using neutral electroless plating processes to minimize damage of the anodized Al substrate; this method used sodium hypophosphite instead of formaldehyde as a reducing agent. The basic electroless solution consisted of CuSO4·5H2O as the main metal source, NaH2PO2·H2O as the reducing agent, C6H5Na3O7·2H2O and NH4Cl as the complex agents, and NiSO4·6H2O as the catalyser for the oxidation of the reducing agent, dissolved in deionized water. The pH of the Cu plating solutions was adjusted using NH4OH. According to the variation of pH in the range of 6.5~8, the electroless plated Cu films were coated on screen printed Ag pattern/anodized Al/Al at 70˚C. We investigated the surface morphology change of the Cu films using FE-SEM (Field Emission Scanning Electron Microscopy). The chemical composition of the Cu film was determined using XPS (X-ray Photoelectron Spectroscopy). The crystal structures of the Cu films were investigated using XRD (X-ray Diffraction). Using electroless plating at pH 7, the structures of the plated Cu-rich films were typical fcc-Cu; however, a slight Ni component was co-deposited. Finally, we found that the formation of Cu film plated selectively on PCB without any lithography is possible using a neutral electroless plating process.

Toxic heavy metals like mercury and cadmium are known to involve in altering the salivary flow so that can be appeared sialorrhea or ptyalism, the condition of increased salivary flow, or xerostomia (“dry mouth”), the condition related to inhibited or decreased salivary flow. Although many people were exposed to these heavy metal in work environment, dental clinics, the mechanism is rarely discussed in the clinical literature. The present study is to carried out analysis of AQP5 expression that play a key role in saliva fluid secretion and cell membrane water permeability on mercury- or cadmium-exposed mice submandibular gland. To investigate AQP 5 expression, immunohistochemical study and western blot assay were carried out on mercury- or cadmium-exposed mice. Additionally, RT-PCR, real- time PCR with specific primers were carried out. Cadmium or mercury exposure led ductal extension, ductal cell increase, and blood vessel increase in mouse submandibular gland. The mRNA and protein expression of AQP5 were increased in time dependent manners on cadmium or mercury exposed mouse. Also, AQP5 were translocated from basolateral membrane to apical membrane of acini cell. In conclusion, toxic heavy metal such as mercury and cadmium appear to alter the AQP5 expression and distribute to apical membrane of ductal cell and lead to alter salivary secretion.

Micro trench structures are applied in gratings, security films, wave guides, and micro fluidics. These micro trench structures have commonly been fabricated by micro electro mechanical system (MEMS) process. However, if the micro trench structures are machined using a diamond tool on large area plate, the resulting process is the most effective man- ufacturing method for products with high quality surfaces and outstanding optical characteristics. A nonferrous metal has been used as a workpiece; recently, and hybrid materials, including polymer materials, have been applied to mold for display fields. Thus, the machining characteristics of polymer materials should be analyzed. In this study, machining characteristics were compared between nonferrous metals and polymer materials using single crystal diamond (SCD) tools; the use of such materials is increasing in machining applications. The experiment was conducted using a square type diamond tool and a shaper machine tool with cutting depths of 2, 4, 6 and 10 µm and a cutting speed of 200 mm/s. The machined surfaces, chip, and cutting force were compared through the experiment.

본 연구에서는 서모소닉 시험을 위한 실용적이고 편리한 PZT 가진 시스템을 구축하고 그 특성을 평가하고자 하였다. PZT 가진기의 성능 평가 및 가진기와 시험체와의 다양한 연결방법의 효과에 대하여 평가하기 위한 실험 을 수행하였다. 실험은 서로 다른 두께를 가진 금속 플레이트를 이용하여 수행되었다. 본 논문에는 실험 장치 및 다양한 연결방법의 성능 시험 결과가 소개되었다. 실험 결과 가진기의 공진 주파수 근처에서 작은 입력 전압과 작은 힘을 이용하여 큰 변형률을 가진 다수의 모드를 가진 할 수 있었고 이 결과는 가진 중에 비선형 진동의 발 생 없이 서모소닉 시험을 위해 충분한 변형률을 얻을 수 있는 가능성을 보여준다. 결과적으로 결함 검출을 위해 작은 크기의 변형률이 필요한 시험체의 경우 작은 PZT 가진기가 간편하고 신뢰성 있는 가진 시스템을 제공 할 수 있다는 가능성을 보여주었다.

In this study, CO₂ adsorbent was produced for minimizing energy loss due to ventilation within the building. For improved selectivity about low concentration of CO₂ in multiple-use facilities, the ball type adsorbent was modified from a commercial zeolite, alumina, alkali metals and activated carbon with mixing LiOH, binder, and H₂O. We measured specific surface area, pore characteristic, and crystal structure of the modified adsorbent. Effects of alkalization on the absorptive properties of the adsorbents were investigated. Continuous column tests (2,000 ppm) and batch chamber tests (4m3, 5,000ppm) showed that the modified adsorbent indicated about the selectivity of CO₂ more than 9.7% (0.613 mmol/g) compared with ordinary adsorbents and CO₂ removal efficiency of 88.8% within l hour, respectively. It was estimated that the modified adsorbent was applicable to indoor environments.

A 72 years old male complained of gingival ulceration and whitish discoloration on the marginal and attached gingival epithelium of left mandibular premolar and molar area, where a porcelain-fused metal (PFM) crown and an ill-fitting gold crown were applied for 10 years, respectively. Recently he had a cancer phobia due to this whitish lesion unhealed even after intensive anti-inflammatory and antibiotic treatment. In the pathological examination the epithelium was hyperkeratotic and acanthomatous with severe inflammatory reaction, and subsequently its basement membrane was distorted and the intercellular spaces between keratinocytes were widened. Particularly, the nuclei of keratinocytes were elongated in the same direction towards the electric current between the dissimilar metallic crowns of PFM gold. In the immunohistochemistry KL1, β-catenin, and S-100 were strongly positive in the epithelium, but consistently weak for TNFα, HSP-70, and β-defensin-1, -2, -3. On the other hand, PCNA, p53, E-cadherin, and pAKT were rarely positive for the epithelium. Interestingly, the hyperkeratinized and inflamed epithelium was strongly positive for a calcium binding protein (S-100), while it showed almost reduced expression of protective molecules (HSP-70, β-defensin-1, -2, -3, and pAKT). Therefore, it was presumed that this localized lichenoid gingivitis was caused by the galvanic current phenomenon with lower cellular and immunological responses contrary to the ordinary oral lichen planus and leukoplakia

무지개 빛을 내는 무기진주광택안료는, 내광성, 내용제성 및 내열성 등이 물리적 화학적 안정성이 우수하여 다양한 분야에서 응용되고 있다. 본 연구는 수열합성방법을 사용하여 마이카 티타니아에 파란색 코팅 안료인 염화코발트를 기본으로 화장품 안료로 사용되는 진주광택안료를 합성하였다. 코발트에 의한 안료의 색상을 보완하고자 코발트와 금속 염의 비를 달리하여 안료를 코팅하고, 이를 통해 금속염의 종류에 따라 다양한 색차값을 구현하는 진주광택 안료를 합성하였다. 코발트와 첨가된 금속 염 전구체의 조성비와, 금속 염의 종류에 따라 코팅 특성과 색상을 조절할 수 있었고, 안료의 다양한 색상변화 특성을 색차계를 통해 확인 하였다. 합성된 안료는 SPM, SEM, XRD, EDS 기기를 통해 특성을 분석하였다.

부산, 경남 지역의 8개 친환경농산물인증 지역에서 카드뮴, 구리, 비소, 수은, 납, 6가크롬, 아연, 니켈 등 8개 중금속의 토양 함량을 조사하였다. 카드뮴은 그 햠량의 순으로 보면 산청, 하동, 사천, 부산순으로 함량이 높았으며, 구리는 김해, 사천, 부산, 고성 순으로, 비소는 사천, 부산, 김해, 고성 순으로, 수은은 고성, 사천, 부산, 김해 순으로, 납은 김해, 사천, 고성, 부산 순으로, 6가크롬은 김해, 부산, 하동, 산청 순으로, 아연은 김해, 부산, 사천, 함양 순으로, 니켈은 사천, 하동, 고성, 산청 순으로 각각 함양이 많았다. 전체적인 함량을 보았을 경우 김해, 사천, 부산 등 낙동강 주변의 평야지대에서 높은 수치를 보였다. 한편 하동, 진주 산청 등 중산간지에서는 전체 중금속 함량이 대체로 낮았다.