• Journal of Preventive Medicine and Public Health
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• v.30 no.3 s.58
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• pp.540-554
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• 1997

The effects of cigarette smoking on the psychosocial distress, the absenteeism, the occupational injuries, and on the prevalence for the accidents were assessed in 795 male workers who had been employed since March 1994. The results show that the prevalence of current smokers were higher in young men, lower educational level, lower income, single men(unmarried or divorced), alcohol drinkers, and blue collar workers. In the bivariate analyses, the workers with the high job demand and low work control were more likely to smoke, although the relationship was not strong. Those who reported lower satisfaction on his job tended to smoke more. Mean scores of psychosocial well-being index(PWI) were higher in current smokers than nonsmokers. For the hierarchical multiple regression analyses, interaction terms between cigarette smoking and job stressors(job demand and work control) were not significant. For smokers, the odds ratios for the occupational injuries, and the accidents were 1.40(95% confidence interval 0.77-2.57) and 1.96 (95% confidence interval 0.75-5.09), respectively. The mean absent day were 4.13 for smokers, 3.65 for nonsmokers, although the differences were not statistically significant. It seems that cigarette smoking had not caused any crucial effects on the psychosocial well-being status and the occupational risks. Some considerations for the further research on the relationship of cigarette smoking on the mental health status and the occupational risks were also discussed.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.5
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• pp.193-200
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• 2016

Characteristics of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors synthesized by solid state reaction and polymerized complex method were comparatively analyzed. In order to evaluate thermal stability of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors at high temperature, phosphorescent properties of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ were investigated with thermal treatment at $1250^{\circ}C$ under reducing atmosphere, which was the general heat treatment conditions for ceramic manufacturing process. The phosphorescent properties of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors synthesized by solid state reaction and polymerized complex method were investigated. The crystal structure and crystallite size were observed through XRD analysis. Microstructure and particle size of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors were analyzed by SEM and PSA. Photoluminescence and afterglow characteristics of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors were measured by spectrofluorometer.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.274-274
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• 2011

백색 유기발광소자는 일반적으로 적색, 청색 및 녹색의 삼원색을 혼합하여 제작하거나 청색 유기발광소자의 빛을 일부 변환시켜 적색 혹은 녹색을 발생하여 백색을 발광하는 구조를 가진다. 백색을 구현하기 위한 삼원색 조합법은 소자의 구조가 복잡하고 제조단가가 상승하며 제작 된 백색 유기 발광 소자내의 발광 영역을 담당하는 물질의 빠른 열화 때문에 발광 스펙드럼에 변화가 생길 수 있다. 본 연구에서 제안하는 색변환 방법은 최적화된 청색 유기발광소자에서 발광된 빛을 색변환 무기물 형광체 층에 의해 재흡수하고 재발광하는 과정에 의해 빛이 발생되기 때문에 색변환 무기물 형광체 층을 사용한 유기발광소자는 구조가 단순하며 무기물 형광체가 외부노출에 안정하기 때문에 상대적으로 안정된 동작이 가능하다. 청색 유기 발광 소자의 효율이나 휘도를 개선하면 소자의 성능이 향상될 수 있는 구조적 장점이 있다. 그러나 기존에 일반적으로 제조하던 방법인 고상반응법에 의한 형광체입자의 크기는 ${\mu}m$ 이상이며 형태도 불규칙한 단점이 있다. 본 연구에서는 졸겔방법으로 녹색 무기물 형광체 $Zn_2SiO_4:Mn$를 제작하였고 청색 형광 유기 발광 소자에 적용하였다. X-선 회절측정 결과는 형성된 녹색 무기물 형광체내의 Zn 이온이 도핑된 Mn 이온에 대체되었음을 보여주었다. 제작된 진청색 형광 OLED의 전계발광 스펙트럼은 461nm에서 발광 스펙트럼을 나태내고 녹색 무기물 형광체는 470 nm에서 여기되어 Mn 이온의 $^4T_1-^6A_1$ 전이에 의하여 526 nm에서 발광을 한다. 이 과정에서 색변환층의 두께가 0.3 mm 이상일 때 461 nm의 발광스펙트럼의 세기가 급격히 줄어들었다. 이 결과는 제작된 녹색 무기물 형광체를 진청색 유기발광소자와 결합하고 색변환층의 두께를 변화하여 제작된 유기발광소자의 발광색을 조절할 수 있음을 보여주었다.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.236-239
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• 2009

Purpose: We wanted to evalulate the clinical results of pectoris major tendon transfer for a neglected winged scapula that was caused by paralysis of the serratus anterior due to injury to the long thoracic nerve. Materials and Methods: A patient had neglected winged scapula that followed an arthroscopic operation for multi-directional instability of the shoulder joint, which was caused by traumatic dislocation. The patient was treated with pectoralis major tendon transfer using the modified Eden-Lange procedure. The range of a motion was improved from forward flexion $90^{\circ}$ and external rotation $70^{\circ}$ to $170^{\circ}$ and $150^{\circ}$ respectively. Results and Conclusion: There were no complications or recurrence and the patient's psychological satisfaction was also high. If the shoulder girdle muscles are intact, except for the serratus anterior, then pectoralis tendon transfer is a satisfactory method that can provide normal scapulo-thoracic motion.

• Journal of Korean Port Research
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• v.13 no.1
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• pp.101-112
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• 1999

Traffic accidents increase with the increase of the vehicles in operation on the street. Especially big traffic accidents composed of over 3 killed or 20 injured accidents with the property damage become one of the serious problems to be solved in most of the cities. The purpose of this study is to build the discrimination model on big traffic accidents using the Quantification II theory for establishing the countermeasures to reduce the big traffic accidents. The results are summarized as follows. 1)The existing traffic accident related model could not explain the phenomena of the current traffic accident appropriately. 2) Based on the big traffic accident types vehicle-vehicle, vehicle-alone, vehicle-pedestrian and vehicle-train accident rates 73%, 20.5% 5.6% and two cases respectively. Based on the law violation types safety driving non-fulfillment center line invasion excess speed and signal disobedience were 48.8%, 38.1% 2.8% and 2.8% respectively. 3) Based on the law violation types major factors in big traffic accidents were road and environment, human, and vehicle in order. Those factors were vehicle, road and environment, and human in order based on types of injured driver’s death. 4) Based on the law violation types total hitting and correlation rates of the model were 53.57% and 0.97853. Based on the types of injured driver’s death total hitting and correlation rates of the model were also 71.4% and 0.59583.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.424-429
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• 2014

YAG:$Ce^{3+}$ phosphor powders were synthesized using $Al(OH)_3$ seeds by means of a PVA-polymer-solution route. Various types of PVA with different molecular weights (different polymerization) were used. All dried precursor gels were calcined at $500^{\circ}C$ and then heated at $1500^{\circ}C$ in a mix of nitrogen and hydrogen gases. The final powders were characterized via XRD, SEM, PSA, PL, and PKG analyses. The phosphor properties and morphologies of the synthesized powders were dependent on the PVA type. As the molecular weight of the PVA was increased, the particle size gradually decreased with agglomeration, and the luminous intensity of the phosphor increased. However, the phosphor powder prepared from the PVA exhibiting very high molecular weight, showed a 531 nm (blue) shift from the 541 nm (yellow) wavelength of the YAG:$Ce^{3+}$ phosphor. Finally, the synthesized YAG:$Ce^{3+}$ phosphor powder prepared from the PVA with 89,000 - 98,000 molecular weight showed phosphor properties similar to those of a commercial phosphor powder, but without a post-treatment process.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.1
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• pp.55-61
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• 2006

신규 $Nb_2Zr_6O_{17-x}N_x$ 광촉매를 고상합성법처리(solid state synthesis) 후 암모니아가스($NH_3$)에 의한 기상처리법(ammonolysis)으로 합성하였다. 합성된 신규 광촉매 및 이를 다시 Pt 및 $RuO_2$를 도핑 하여 $H_2S$를 광분해하여 수소를 발생 실험을 수행하였다. 이 신규 oxynitrid계 광촉매는 가시광하에서 $H_2S$를 광분해하여 수소를 발생하는(Quantum yield = 13.5 %) 우수한 광촉매 활성을 보여주었다.

• Journal of Oriental Neuropsychiatry
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• v.19 no.3
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• pp.171-178
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• 2008

Objective: The purpose of this study is investigation of relationship between HRV(Heart Rate Variability) and Hwa-Byung in general population. Methods: HBDIS(Hwa-Byung Diagnostic Interview Schedule) was carried out for 658 participants in Wonju Cohort study that include short term electrode HRV test. We also classified whole participants into sex. Collected data was analyzed by the Mann-Whitney U test. Result: SDNN(Standard Deviation of NN interval) was significant different in HRV between Normal and Hwa-Byung of male participants. Conclusion: In the findings of this study, Hwa-Byung is not closely related to the autonomic nerve system.

• Transactions of Materials Processing
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• v.7 no.2
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• pp.139-149
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• 1998

The technology of Semi-Solid Forging(SSF) has been actively developed to fabricate near net shape products using light and hardly formable materials. Generally the SSF process is composed of slug is compressed during a certain holding time in order to completely fill the die cavity and accelerate the solidification rate. The decision of compression time is important since it can affect microstructural characteristics, mechanical properties and shape of products.. In order to determine it proper overall heat transfer coefficient between the slug and dies should be investigated. This paper presents the procedure to find the overall heat transfer coefficient between the slug and dies by nonlinear optimization of temperature and solid fraction for a cylindrical slug at compression step in closed-die semi-solid forging. In finite ele-ment heat transfer analysis release of latent heat during solidification was considered. The influence of the predicted compression time on miscrostructural characteristics mechanimcal properties and shape of products is finally investigated by experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.199-203
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• 1995

The technology of Semi-Solid Forging (SSF) has been actively developed to fabricate near-net- shape products using light and hardly formable materials, the SSF process is composed of slug heating, forming, compression holding and ejecting step. After forming step in SSF, the slug is compressed during a certain holding time in order to be completely filled in the die cavity and be accelerated in solidification rate. The compression holding time that can affect mechanical properties and shape of products is important to make decision, where it is necessary to find overall hert transfer coefficeient properly which has large effect on heat transfer between slug and die. This paper presents the procedure to predict compression holding time of octaining the final shaped part with information of temperature and solid fraction for a cylindrical slug at compression hoiding step in closed-die compression process using heat transfer analysis considering latent heat by means of finite element method. The influence of the predicted compression hoiding time on mechanical properties of products is finally investigated by experiment.