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장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4
Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.
Park, Hyeong Bin,Lee, Byoung-Doo,Lee, Chang Woo,Hwang, Jung Eun,Park, Hwan Joon,Kim, Seongjun,An, Jiae,Kim, Pyoung Beom,Kim, Nam Young National Institute of Ecology 2021 국립생태원회보(PNIE) Vol.2 No.4
Iris dichotoma Pall. found on Daechung Island in Korea has been designated as an endangered species. To aid in conservation efforts of this species, this study investigated its germination characteristics and seed dormancy type. Four sets of seeds were incubated at different temperatures (4/1℃, 15/6℃, 20/10℃, and 25/15℃). One set of seeds was cold stratified (4 weeks at 4/1℃). The final germination rate and mean germination time showed that the optimal germination temperature was 25/15℃. Final germination rates were ~70%, showing no significant difference among temperature treatments. However, mean germination time were significantly different among all temperature treatments except for 4/1℃. Mean germination time for seeds with temperature treatments of 15/6℃, 20/10℃, and 25/15℃ were 3.2, 2.1, and 1.5 weeks, respectively. At 25/15℃, the mean germination time was half of that at 15/6℃. Seeds of I. dichotoma had fully developed embryos at the time of dispersal. No additional growth of the embryo was observed. Cold stratification did not affect the final germination rate or the mean germination time. This study shows that seeds of I. dichotoma have no physiological or morphological dormancy, unlike other members of the Iris genus known to have seed dormancy that needs a relatively high incubation temperature (≥25/15℃) for mass propagation to occur. These results will be useful for understanding ecophysiological mechanisms related to the species' habitat. They are also useful for mass propagation of I. dichotoma for the purpose of conserving this endangered species.
Park, Hyeong-Ho,Law, Wai Lung,Zhang, Xin,Hwang, Seon-Yong,Jung, Sang Hyun,Shin, Hyun-Beom,Kang, Ho Kwan,Park, Hyung-Ho,Hill, Ross H.,Ko, Chul Ki American Chemical Society 2012 ACS APPLIED MATERIALS & INTERFACES Vol.4 No.5
<P>A novel ultraviolet (UV)-assisted imprinting procedure that employs photosensitive tin(II) 2-ethylhexanoate is presented for the facile size-tunable fabrication of functional tin dioxide (SnO<SUB>2</SUB>) nanostructures by varying annealing temperatures. These imprinted SnO<SUB>2</SUB> nanostructures were also used as new masters for size reduction lithography. SnO<SUB>2</SUB> lines down to 40 nm wide were obtained from a silicon master with 200 nm wide lines by simply performing size reduction lithography twice. This leads to 80 and 87.5% reduction in the width and height of imprinted lines, respectively. An imprinted pattern annealed at 400 °C demonstrated transmittance greater than 90% over the range of 350–700 nm, which is high enough to make the pattern useful as a transparent SnO<SUB>2</SUB> mold. This demonstrated approach allows the accessibility to size-tunable molds, eliminating the need for conventional expensive imprinting masters with very fine structures, as well as functional SnO<SUB>2</SUB> nanostructures, potentially useful in applications where ordered surface nanostructures are required, such as photonic crystals, biological sensors, and model catalysts.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2012/aamick.2012.4.issue-5/am300203g/production/images/medium/am-2012-00203g_0001.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am300203g'>ACS Electronic Supporting Info</A></P>
Park, Hyeong-Ho,Zhang, Xin,Hwang, Seon-Yong,Jung, Sang Hyun,Kang, Semin,Shin, Hyun-Beom,Kang, Ho Kwan,Park, Hyung-Ho,Hill, Ross H,Ko, Chul Ki Elsevier 2012 SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS Vol.13 No.2
<P>We present a simple size reduction technique for fabricating 400 nm zinc oxide (ZnO) architectures using a silicon master containing only microscale architectures. In this approach, the overall fabrication, from the master to the molds and the final ZnO architectures, features cost-effective UV photolithography, instead of electron beam lithography or deep-UV photolithography. A photosensitive Zn-containing sol–gel precursor was used to imprint architectures by direct UV-assisted nanoimprint lithography (UV-NIL). The resulting Zn-containing architectures were then converted to ZnO architectures with reduced feature sizes by thermal annealing at 400 °C for 1 h. The imprinted and annealed ZnO architectures were also used as new masters for the size reduction technique. ZnO pillars of 400 nm diameter were obtained from a silicon master with pillars of 1000 nm diameter by simply repeating the size reduction technique. The photosensitivity and contrast of the Zn-containing precursor were measured as 6.5 J cm<SUP>−2</SUP> and 16.5, respectively. Interesting complex ZnO patterns, with both microscale pillars and nanoscale holes, were demonstrated by the combination of dose-controlled UV exposure and a two-step UV-NIL.</P>
Compact and multiplexible hydrogen gas sensor assisted by self-referencing technique.
Park, Kwan Seob,Kim, Young Ho,Eom, Joo Beom,Park, Seong Jun,Park, Min-Su,Jang, Jae-Hyeong,Lee, Byeong Ha Optical Society of America 2011 Optics express Vol.19 No.19
<P>We have experimentally implemented a multiplexible but compact fiber sensor system suitable for multipoint sensing of hydrogen gas leakage. By making dual cavities along an optical fiber and coating a palladium film only at the end of the fiber tip, the measurement errors induced by the optical source power fluctuation and the mechanical perturbation in the lead fiber could be compensated. By adjusting the length of the dual-cavity, the capability of multiplexing several hydrogen sensors could be achieved. The experiment results showed that the response speed of the sensor was increasing with temperature, but at a low temperature the response amplitude became large.</P>
Park, Hyeong-Beom,Jung, Myung-Ho,Cho, Jung-Hyuck,Oh, Chang-Hyun Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.8
The synthesis of a new series of 1$\beta$-methylcarbapenems having spiro[2,4]heptane moieties is described. Their in vitro antibacterial activities against both Gram-positive and Gram-negative bacteria were tested and the effect of substituents at the pyrrolidine ring was investigated. Most of the compounds were found to be more active compared to imipenem against Gram-negative bacteria. A particular compound (IIIc) having 7-oxo-5- azaspiro[2,4]heptane moiety showed the most potent antibacterial activity.