• Proceedings of the Safety Management and Science Conference
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• 2009.04a
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• pp.79-91
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• 2009

The government separated and established the industrial safety and health law from the Labor Standard law since 1981 to promote the labor's working environment and to improve the conditions of laborers. The government made a lot of effort to discharge the industrial safety and health law by continuous revision of the law thereafter. it is, however, difficult to establish clear-cut lines of authority and responsibility due to the fact that the substantial application of the industrial safety and health law is adapted by enterprise's autonomous management. There are frequent industrial disasters on the small and medium enterprises which have financial difficulty and it means this causes much more social cost. Finally, for the improvement of laborer's safety, health and working environment in the small and medium enterprises we need to raise the effectiveness of the industrial safety and health law through enhancing a government-office's administration and surveillance with the changing mind of a business proprietor. On this paper, we research on the actual condition of the administration, inspection and regulation of safety and health by means of the industrial safety and health law. Thereafter we analyze how much the Korea Occupational Safety & Health Agency and vicarious businesses of safety & health management help. we used the survey method to gather data from 380 laborers directly and analysed the data by SPSS v17.0.

• Journal of Plant Biology
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• v.3 no.2
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• pp.29-34
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• 1960

From the view point of phytopathological anatomy, the author has tried to study the effect of the shoot cluster disease virus on the internal structure of vascular tissues of chinese date tree (Ziziphus jujuba var. inermis Rehd.) comparing healthy checks and diseased plants. The materials were collected at the several sites, Kumgock-Ri, Masuc-Ri, Kyungi-Do, and near the campus of Korea University and around the area of Chongam-Dong, Seoul City, from August 15th to September 5th 1959. The leaf materials of healthy and diseased plants are fixed and aspirated in two kinds of killing solutions, formalin-acetic acid alcohol solution and Craf III solution. Sections were cut at 5-10$\mu$ thickness and stained with the double staining reagents of safranin and fast green. In this experiment the author has observed that there are marked structural changes in the infected plants in contrast of healthy checks. As figures 3-7 show that the following characteric changes have taken place on infected plants: 1) the arrangement of irregularly developed sieve elements in phloem, 2) the degeneration of phloem elements, 3) the irregular arrangement of epidermis in mid-vein, 4) more necrosis is observed among the parenchymatous cells, 5) abundant accumulatin of starch grains in parenchymatous cells, . In contrast to the above irregularities caused by the virus disease, the healthy checks appear normal structures as shown in figures 1 and 2. In adding to the all features noted above, the author could also observe an interesting feature that the xylem elements in mid-vein vascular bundle tissues are considerably disorganized to show the unspecialized vessel elements, the irregularly arranged xylem elements. However, this kind of irregularities which occur in xylem under the virus infection has not been reported previously. The features noted on the internal structure of vascular bundle under the condition of infection by the shoot cluster disease on chinese date trees appear to be more or less closely similar to the symptoms of the bunchy-top of banana and the yellow dwarf disease of barley in respect to the fact that whether phloem necrosis takes place as a primary symptom or a secondary symptom. In all these disease, primary histological changes of hypoplasia and hypertrophy are preceeded by the necrosis of phloem.

• Food Science and Preservation
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• v.24 no.3
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• pp.361-366
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• 2017

This study investigated quality change of ginseng depending on far-infrared (FIR) drying methods. The ginseng was cut into 2 mm slices and measured moisture content (MC), color, total polyphenol content (TPC), total flavonoid content (TFC) and DPPH radical scavenging activity (DPPH). The color values (L, a, and b) were decreased after far-infrared (FIR) drying. As increase in drying time, color was changed. Considering quality parameters including MC, TPC, TFC, and DPPH, the optimum condition for drying was set at $65^{\circ}C$ for 60 min. Furthermore, we compared color and functional compounds depending on drying process including FIR, freeze-, vacuum, and hot-air drying. The color values of ginseng were decreased when dried using vacuum and hot-air. While the color values of ginseng were increased after freeze drying. Comparison with another drying method, FIR drying presented the highest color difference. FIR and vacuum-dried ginseng indicate higher contents of TPC and TFC than freeze- and hot air-dried ginseng. And hot-air-dried ginseng present the highest DPPH when compared to another drying methods. On the other hand, freeze dried ginseng show the lowest TPC, TFC, and DPPH.

• Journal of Korean Library and Information Science Society
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• v.49 no.4
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• pp.405-427
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• 2018

This study examined system, form and contents of including its publication in depth through the analysis on the publication of those days, present condition of extant edition, system and publication, illustrator etc., targeting series which was published in the liberation period. As for series which was published by Eulyoo Publishing and Joseon Children Culture Association(Ahyeop) for building children's life liberation and children culture, 5 books still remain now. For the extinct edition, this study confirmed publication history of books based on the advertisement carried on the newspaper which was published of the time. As a result of analyzing extant edition, this study found that the book was composed equally as a system of cover, beginning, body and the end, and the body was characterized by the composition of 3-cut comic and story as a form of storybook. The size of the book is A5 book size with 32 pages of quantity and was published as a semi-hardcover bound book. As for illustrators, Kim brothers (Yong-hwan, Eui-hwan) who played an active part in the field of art of the time participated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.4
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• pp.23-30
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• 2022

Small-scale production is increasing, and the manufacturing industry is gradually changing into a smart manufacturing industry. Therefore, research on securing optimal cutting conditions for factors affecting machining precision during cutting is very important. Therefore, the purpose of this study is to After machining the inner diameter hole of SCM415 steel with a cermet tool on a CNC automatic lathe, the surface roughness, dimensional accuracy, and dimensional straightness are measured according to the feed rate to analyze the machining characteristics and suggest optimal cutting conditions. The test material was cut using a cermet tool for secondary cutting after a round bar with a diameter of 20 mm was mounted on a CNC automatic lathe. The cutting length was fixed at 0.5 mm, and the cutting speed was fixed at 3200 rpm. When the feed rate was changed to 0.05, 0.1, and 0.15 mm/rev, the respective surface roughness during the 15th test was measured. Consequently, The lower the feed rate, the better is the surface roughness. In addition, the optimum cutting conditions for SCM415 steel were observed to be the most ideal cutting conditions than the condition of 0.05 mm/rev at a cutting speed of 3,200 rpm and a feed rate of 0.1 mm/rev.

• Journal of Korean Tunnelling and Underground Space Association
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• v.10 no.2
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• pp.105-118
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• 2008

Shotcrete is one of the main support materials in tunnelling. Its bonding state on excavated rock surfaces controls the safety of the tunnel: De-bonding of shotcrete from an excavated surface decreases the safety of the tunnel. Meanwhile, the bonding state of shotcrete is affected by blasting during excavation at tunnel face as well as bench cut. Generally, the bonding state of shotcrete can be classified as void, de-bonded, or fully bonded. In this study, the state of the back-surface of shotcrete is investigated using impact-echo (IE) techniques. Numerical simulation of IE technique is performed with ABAQUS. Signals obtained from the IE simulations were analyzed at time, frequency, and time-frequency domains, respectively. Using an integrated active signal processing technique coupled with a Short-Time Fourier Transform (STFT) analysis, the bonding state of the shotcrete can be evaluated accurately. As the bonding state worsens, the amplitude of the first peak past the maximum amplitude in the time domain waveform and the maximum energy of the autospectral density are increasing. The resonance frequency becomes detectable and calculable and the contour in time-frequency domain has a long tail parallel to the time axis. Signal characteristics with respect to ground condition were obtained in case of fully bonded condition. As the ground condition worsens, the length of a long tail parallel to the time axis is lengthened and the contour is located in low frequency range under 10 kHz.

• Journal of Science and Technology Studies
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• v.3 no.2 s.6
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• pp.29-60
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• 2003

Inter-Korean Cooperation in Science and Technology will contribute to building the trust between S.K and N.K as a leading factor and cut down the cost of unification by diminishing the technology lag and the gap of economic level. This study has shown that we can increase the productivity of unified Korea Innovation system if we systematically analyse the present condition of the Inter-Korean Cooperation and promote Inter-Korean Cooperation. In this study, the author analyses the present condition of the Inter-Korean Cooperation with integrated framework of three aspects to clear up the policy of Inter-Korean Cooperation. First, in the national aspect, we make use of the notion of international cooperation and multilateral mechanism of an international organization. Thereafter, we make out the alternatives in the aspects of international relationship and legal and institutional view Second, in the unification aspect, we consider the Inter-Korean Cooperation by the notion of national innovation system. Thereafter, we make out the alternative in the aspect of a phase-dependent approach. Finally, in technology aspect, we consider the Inter-Korean Cooperation by the notion of technology gap, the framework of technology transfer, and technology dependency theory. As a conclusion, through this study, the author have tried to integrate the various theoretical backgrounds. As a result, the author could analyse the present condition of ter-Korean Cooperation in Science and Technology and team a good lesson from it; Therefore, we can use it as a means of evaluation on a cooperation program and prediction for the future status of cooperation.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.642-653
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• 2006

Purpose : The purpose of this study was to investigate the effect of the output energy(voltage) of laser welding on the strength and properties of joint of cast titanium(CP Gr II) and titanium alloy(Ti-6Al-4V). Material and method : Cast titanium and its alloy rods(ISO6871) were prepared and perpendicularly cut at the center of the rod. After the cut halves were fixed in a jig, and the joints welded with a laser-welding machine at several levels of output voltage of $200V{\sim}280V$. Uncut specimens served as the non-welded control specimens The pulse duration and pulse spot size employed in this study were 10ms and 1.0mm respectively. Tensile testing was conducted at a crosshead speed of 0.5mm/min. The ultimate tensile strength(MPa) was recorded, and the data (n=6) were statistically analyzed by one-way analysis of variance(ANOVA) and Scheffe's test at ${\alpha}$=0.05. The fracture surface of specimens investigated by scanning electron microscope (SEM). Vickers microhardness was measured under 500g load of 15seconds with the optimal condition of output voltage 280V. Results : The results of this study were obtained as follows, 1. When the pulse duration and spot size were fixed at 10ms and 1.0mm respectively, increasing the output energy(voltage) increased UTS values and penetration depth of laser welded to titanium and titanium alloy. 2. For the commercial titanium grade II, ultimate tensile strength(665.3MPa) of the specimens laser-welded at voltage of 280V were not statistically(p>0.05) different from the non-welded control specimens (680.2MPa). 3. For the titanium alloy(Ti-6Al-4V), ultimate tensile strength(988.3MPa) of the specimens laser-welded at voltage of 280V were statistically(p<0.05) different from the non-welded control specimens (665.0MPa). 4. The commercial titanium grade II and titanium alloy(Ti-6Al-4V) were Vickers microhardness values were increased in the fusion zone and there were no significant differences in base metal, heat-affected zone.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.17
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• pp.7433-7436
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• 2014

Background: Gastric cancer (GC) is the second cause of cancer related death in the world. It may develop by progression from its precancerous condition, called gastric atrophy (GA) due to gastritis. The aim of this study was to evaluate the accuracy of serum levels of pepsinogens (Pg) and gastrin-17 (G17) as non-invasive methods to discriminate GA or GC (GA/GC) patients. Materials and Methods: Subjects referred to gastrointestinal clinics of Golestan province of Iran during 2010 and 2011 were invited to participate. Serum levels of PgI, PgII and G17 were measured using a GastroPanel kit. Based on the pathological examination of endoscopic biopsy samples, subjects were classified into four groups: normal, non-atrophic gastritis, GA, and GC. Receiver operating curve (ROC) analysis was used to determine cut-off values. Indices of validity were calculated for serum markers. Results: Study groups were normal individuals (n=74), non-atrophic gastritis (n=90), GA (n=31) and GC patients (n=30). The best cut-off points for PgI, PgI/II ratio, G17 and HP were $80{\mu}g/L$, 10, 6 pmol/L, and 20 EIU, respectively. PgI could differentiate GA/GC with high accuracy (AUC=0.83; 95%CI: 0.76-0.89). The accuracy of a combination of PgI and PgI/II ratio for detecting GA/GC was also relatively high (AUC=0.78; 95%CI: 0.70-0.86). Conclusions: Our findings suggested PgI alone as well as a combination of PgI and PgI/II ratio are valid markers to differentiate GA/GC. Therefore, Pgs may be considered in conducting GC screening programs in high-risk areas.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.64-71
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• 2020

Gloiopeltis tenax is one of the most economically useful species in China and Japan that has been applied to glue and food since ancient times. The material used in the experiment was a large quantity of basal crusts obtained from the culture of tetraspores that were released from the mature tetrasporophytes collected at Gyeokpori, Byeonsan-myeon, Buan-gun, Jeollabuk-do in Korea. The basal crusts were cut into quadrisect under a dissecting microscope so as to monitor the process of regeneration and growth. The cut crusts were cultured under varying conditions, where the photoperiod was 16:8 h L:D; the temperature range was 10, 15, 20, and 25℃; the irradiance range was 30 and 85 µmol photons m^-2s^-1. The quadrisect basal crusts grew to an oval shape, then formed a vertical axis of cylindrical shape. The maximum growth of basal crusts was 9.61±3.59 mm² under the condition of 15℃ temperature and 85 µmol photons m^-2s^-1 irradiance, after 12-weeks culture. The mean relative growth rate after 12-weeks culture showed the maximum rate of 5.15±0.80 %day^-1 at 15℃ and the minimum growth rate was 3.15±0.94 %day^-1 at 10℃, with a statistically significant difference (p < 0.05). In conclusion, it has shown the possibility that growth of basal crusts of G. tenax is one of the good farming method of potential alga.