• Title/Summary/Keyword: White-Metal

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Fabrication of $Cr^{3+}$ doped sapphire single crystal by high temperature and pressure acceleration method (고온가압 확산법에 의한 $Cr^{3+}$ 고용 사파이어 단결정의 제조)

  • 최의석;정충호;김무경;김형태;홍정유;김유택
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.1
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    • pp.29-33
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    • 1999
  • Transition metallic $Cr^{3+}$ ion was diffused in white sapphire {0001}, ${10\bar{1}0}$ crystal plane which were grown by the Verneuil, it enhanced and changed the physical, electrical and optical properties of sapphires. After mixing the metallic oxide and metal powder, it were used for diffusion powder. When it was used the mixing powder of metal and metallic oxide, the dopping was slowly progressed and it needed the longer duration time and higher temperature, relatively. Metallic powder was vapoured under $1{\times}10^{-4}$ torr of vacuum pressure at $2050^{\circ}C$, first step, it were kept by the diffusion condition of 6 atm of $N_{2}$ accelerating pressure at $2050~2150^{\circ}C$. Each surface density of sapphire crystal are 0.2254(c) and $0.1199\;atom/{\AA}^2(a)$. The color of the Cr-doped sapphires was changed to red. Dopping reaction was come out more deep in the plane of ${10\bar{1}0}$ than {0001}. It was speculated that the planar density was one of the factors to determine diffusion effect.

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Determination of Metal Levels in Shamma (Smokeless Tobacco) with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in Najran, Saudi Arabia

  • Brima, Eid I.
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.10
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    • pp.4761-4767
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    • 2016
  • Objective: The use of Shamma (smokeless tobacco) by certain groups is giving rise to health problems, including cancer, in parts of Saudi Arabia. Our objective was to determine metals levels in Shamma using inductively coupled plasma mass spectrometry (ICP-MS). Methods: Thirty-three samples of Shamma (smokeless tobacco) were collected, comprising four types: brown Shamma (n = 14.0), red Shamma (n = 9.0), white Shamma (n = 4.0), and yellow Shamma (n = 6.0). All samples were collected randomly from Shamma users in the city of Najran. Levels of 11 elements (Al, As, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, and Zn) were determined by ICP-MS. Results: A mixed standard (20 ppb) of all elements was used for quality control, and average recoveries ranged from 74.7% to 112.2%. The highest average concentrations were found in the following order: Al ($598.8-812.2{\mu}g/g$), Mn ($51.0-80.6{\mu}g/g$), and Ni ($23.2-53.3{\mu}g/g$) in all four Shamma types. The lowest concentrations were for As ($0.7-1.0{\mu}g/g$) and Cd ($0.0-0.06{\mu}g/g$). Conclusions: The colour of each Shamma type reflects additives mixed into the tobacco. Cr and Cu were showed significant differences (P < 0.05) among Shamma types. Moreover, Pb levels are higher in red and yellow Shamma, which could be due to use (PbCrO4) as yellow colouring agent and lead tetroxide, Pb3O4 as a red colouring agent. The findings from this study can be used to raise public awareness about the safety and health effects of Shamma, which is clearly a source of oral exposure to metals.

A Study on Tensile Shear Characteristics of Dissimilar Joining Between Pre-coated Automotive Metal Sheets and Galvanized Steels with the Self-Piercing Rivet and Hybrid Joining (Self-Piercing Rivet과 Hybrid Joining을 이용한 자동차용 선도장 칼라강판과 용융아연도금강판의 접합부 기계적 성질 평가)

  • Bae, Jin-Hee;Kim, Jae-Won;Choi, Ildong;Nam, Dae-Geun;Kim, Jun-Ki;Park, Yeong-Do
    • Journal of Welding and Joining
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    • v.34 no.1
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    • pp.59-67
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    • 2016
  • The automotive manufactures increase their use of lightweight materials to improve fuel economy and energy usage has a significant influence on the choice of developing materials. To meet this requirements manufacturers are replacing individual body parts with lightweight metals, for these the process treating and painting surfaces is changing. The pre-coated steels are newly developed to avoid the conventional complex and non-environmental painting process in the body-in-white car manufacturing. The development of new joining techniques is critically needed for pre-coated steel sheets, which are electrically non-conductive materials. In the present study, dissimilar combination of pre-coated steel and galvanized steel sheets were joined by the self-piercing rivet, adhesive bonding and hybrid joining techniques. The tensile shear test and free falling high speed crash test were conducted to evaluate the mechanical properties of the joints. The highest tensile peak load with large deformation was observed for the hybrid joining process which has attained 48% higher than the self-piercing rivet. Moreover, the hybrid and adhesive joints were observed better strain energy compared to self-piercing rivet. The fractography analyses were revealed that the mixed mode of cohesive and interfacial fracture for both the hybrid and adhesive bonding joints.

Temperature and Coverage Dependent Quasi-reversible Two-photon Photoemission of 1-phenyl-1-propyne on Cu(111)

  • Sohn, Young-Ku;Wei, Wei;Huang, Weixin;White, John M.
    • Bulletin of the Korean Chemical Society
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    • v.32 no.6
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    • pp.1980-1984
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    • 2011
  • A temperature- and coverage-dependant quasi-reversible change in two-photon photoemission (2PPE) of chemisorbed 1-phenyl-1-propyne (PP) on Cu(111) is reported. For PP on Cu(111) at 300 K probed at a photon energy of 4.13 eV, two broad peaks of comparable intensity show final state energies of 7.25 and 7.75 eV above the Fermi level. The former peak could be assigned to the first image potential state (IS, n = 1) and/or unoccupied molecular orbital (UMO), located at 3.1 eV above the Fermi level. The latter is plausibly attributed to a mix of unoccupied higher-order IS (and/or UMO) and occupied surface state (SS) of Cu(111). With decreasing the temperature, the former 2PPE peak shows a shift in position by about 0.2 eV, and the latter exhibits a dramatic increase in intensity. In the system, intermolecular interactions (and/or order-disorder transition) of PP and substrate lattice temperature may play a significant role in change in photoexcitation lifetime (or excitation cross-section), and the unoccupied molecular orbital (UMO)-metal (IS) charge transfer coupling. Our unique 2PPE results provide a deeper insight for understanding photoexcitation charge transfer with temperature in an organic molecule/metal system.

A Study on the Outdoor Lighting of Campuses on the Ground of the User-Satisfaction (이용자 만족도에 의거한 캠퍼스 옥외조명 연구)

  • Kim Dong-Chan;Min Chang-Ki
    • Journal of the Korean Institute of Landscape Architecture
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    • v.33 no.1 s.108
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    • pp.1-9
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    • 2005
  • The purpose of this study is to form a night-view at a university to satisfy users through case studies of four representative university campuses with analyzing the lighting conditions and facility satisfaction. The result of this study is following. From the present lighting status, there are 664(l9types) lightings at Kyunghee University, 350(17types) at Sungkyunkwan University and 437(l9types) at Ajou University. Main materials of the lightings are metal, iron and stainless. Moreover, most illuminants are white-colored metal-halide lamp. There is no specially designed lighting facility because ready-made goods were used. Furthermore, the locations of lightings are not suitable so some are useless. Most main spatial illuminations are not satisfying outdoor standard, so it can be concluded that the designs of present campuses are not carrying on with-out plans. From the result, present campus lighting does not satisfy the desire of users in aesthetic and functional point of view but consider the luminosity. However, even though the luminosity does not standardize the law. It is because the design does not reflect a suitable standard with desire of users and it does not have a long term plan. Moreover, the campus design has no study about development plan even though it has enough green area which has a potential possibility to overcome the lack of green areas in a city. Therefore, it is needed to design a comprehensive campus plan which satisfies the desire of students and residents with considering promotion of excitement and harmony through adjusting luminosity of the lighting facilities and supplying various lighting resources.

Appropriate Digital Camera System for Digital Ultraviolet Photography (디지털 자외선 사진을 위한 적정 디지털 카메라 시스템)

  • Lee, Young-Kyu;Har, Dong-Hwan
    • The Journal of the Korea Contents Association
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    • v.10 no.7
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    • pp.40-48
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    • 2010
  • Reflected-Ultraviolet photography is applied to the evidence of crime, Archaeology, and Dermatology. In the past, Ultraviolet photography was done with standard black-and-white film. Because emulsion of film is more sensitive to near UV light than CCD(Charge Coupled Device) or CMOS(Complementary Metal-Oxide-Semiconductor)of digital camera. In this research, we purpose to improve qulity of ultraviolet photographs and to find out the best alternative digital camera by utilizing a cunsumer digital camera. To achieve theses, we removed IR cutoff filter from digital camera. And by using modified UV pass filter, we verified the increase of image resolution of digital ultraviolet photographs. Also, we analyze reproducibility of digital ultraviolet photographs according to type, size, pixel of image sensor. Furthermore, this research resulted in the development of an practical digital camera system by utilizing a cunsumer digital camera. Eventually, it will contribute to practical use in the various field of digital ultraviolet photographs

A Study on Psoriasis from a Viewpoint of the Dryness and the Dampness Theory in Oriental Medicine (조습관점에서 본 건선 연구)

  • Kim Byoung Soo;Kook Sun Ho;Kang Jung Soo
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.16 no.4
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    • pp.642-648
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    • 2002
  • The Dryness and the Dampness is the congential nature. the Water and Fire is the acquired action. the skin is related to the physiological function of the lung, so the skin is the domain of the lung. the lung belongs to the dryness-metal(燥金). And the Dryness and the Dampness in the six pathogenic factors exert a important pathogenic influence upon the skin. Psoriasis is a chronic skin condition charactered by red, silver scaly patches in the affected areas, it is caused by excessive growth of the top layer of the skin(epidermis). Scalp psoriasis affects at least two thirds people who have psoriasis. Generally, the scalp will have plaque psoriasis characterized by elevated, inflamed, lesions covered with silvery white scales. The lesion of psoriasis is head, elbow and knee that are yang-channels in Oriental medicine. The syndrome falls with in the purview of the dryness-metal(燥金). In time, psoriasis takes a turn for the worse in the winter season. In space, many of people in comparison to the average in the world have psoriasis in high latitude that is dry and cold, for instance, the Scandinavian peninsula. Deficiency of yin-fluid and blood course often the dryness-syndrome, for instance, psoriasis, etc. So psoriasis is one of the dryness-syndrome in Oriental medicine.

The Level of Exposure to Electromagnetic Fields Strength from VDT According to the Arrangement of Working Space VDT (영상표시단말장치의 작업공간 배열에 따른 전자파 폭로 정도)

  • Han, Sangil;Lee, Sehoon
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.8 no.1
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    • pp.146-154
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    • 1998
  • This study was designed to investigate the workers' exposure level to electromagnetic field(EMF) in accordance with the VDT arrangement in the work place and distance from VDT. Author compared the exposure strength of EMF in line group(workers exposed to EMF from both front and back side) and in shielding group(workers exposed to EMF exclusively from front side). The levels of EMF at 30cm and 50cm from front side and at 30cm from back side of VDT were also measured. The result were as follows: 1. Mean distance between a monitor and a worker in shielding group ($47.7{\pm}8.7cm$) significantly longer than that in line group($44.3{\pm}7.2cm$). Strength of EMF in shielding group [$1.3{\pm}0.7V/m$ (electric field) and $18.2{\pm}11.5mA/m$ (magnetic field) were lower than in line group [$1.4{\pm}0.6V/m$ and $26.6{\pm}11.6mA/m$, respectively] at the workers' position. 2. The strength of EMF was decreased with the distance from VDT. The strength at 70cm from VDT was nearly the same as the background strength in the ordinary office rooms. 3. Working distance from 9 inch monitor was significantly shorter than that from 14 inch and wider sized monitors. 4. The strength of EMF in extremely low frequency spectrum of color monitors was higher then that of black and white monitor. 5. Metal coated filters significantly decreased the electric field strength of EMF when earth line was connected. Metallic shield was effectively decreased the EMF strength from VDT, but wooden shield was not. From the above results, line type arrangement of VDT in the work place using metallic shield at the back side of VDT, and metal coated filter to monitor with application of earth line were recommended. It is also recommended to maintain workers position to be 60cm or more distance from monitor and 140cm or more between VDTs for minimizing workers' exposure to EMF.

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A Study on Ethnic look Expressed in Modern Fashion (현대 패션에 나타난 민속풍(Ethnic look)에 관한 연구)

  • 정연자
    • Journal of the Korean Home Economics Association
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    • v.31 no.4
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    • pp.215-229
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    • 1993
  • As a result of making an inquiry into the ethnic look of each region appearing in present-day fashion by Asia. America and Oceania. Africa and Europe as mentioned above, its characteristics could be summarized as follows: Firstly the Asian ethnic look consists of Indian, Chinese and Japanese looks as mainstream. In terms of form, the draped form constituted its mainstream, and both the draped form and the tunic form are appearing Simultaneously in the Chinese look. And in respect to color the Indian look is using luxurious primary colors red, blue, yellow and green and other regions are making overall use of natural colors. With respect to ornament various kinds of ornaments is utilized in Indian's Sari and turban. Chines's Coolie hat, straw hat and embroidery, knotted button, and bead ornament, and Japan's Obi and Obijime, etc. Secondly in America and Oceania, costurme representing the Indian look in North America and the picture of Western pioneer, and the Peruvian, Mexican and chilean ethnic looks in South America were expressing much. Here, the form consistied a draped form as its main strem, such colors as yellow, purple, grey, etc were much utilized, and the material of costume comprised knits, cotton and the like. And the ornament consisted of hats, tassel ornaments, bead ornaments, metal chain belt, long braided hair, etc. Thirdly, the African ethnic look had an exposing form and a draped form, and such colors as black, white, yellow, brown, etc were used as the fashion color. Ornaments such as precious stone, bead ornaments, animal bones, straw metal ornament, etc were used as fashion decorations. Fourthly, Russia's Cossack look, Bulgaria's Bavshika look, spain's ethnic look cane to the fore as the European look Both the draped form and the tunic form were used simultaneously as fashion form. And grey, brown, purple, etc were much used as fashion color in the European look. Such ornaments as Cossack. Bavshka, boots, tassel ornaments were much used and paisley pattern also was used.

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Ceramic materials for chair side CAD/CAM (체어사이드 CAD/CAM에서 사용하는 세라믹 소재)

  • Kim, Heechul
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.23 no.1
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    • pp.16-26
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    • 2014
  • Materials that can be use in CAD/CAM are composite, ceramic, hybrid and metal. Among the available materials, monolithic ceramic technique which is the manufacturing technique using one type of the materials is mainly used in a dental office. It is the technique where final tooth-shaped prostheses are made from the material block and used after polishing or applying heat and that does not require traditional ceramic build-up process. Although shot of esthetic quality, because manufactured within 1 hour the monolithic ceramic technique has advantages such as that treatment can be completed in one day and in one time visit, that stability of the material is high because there are low possibility of distort by not melting and phase transformation, and that it can be easily worked in the office with computer assisted devices. We classified the materials that can be used in this technique based on their generations from clinical stand point.