• Journal of the Korean Society for Heat Treatment
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• v.8 no.1
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• pp.32-43
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• 1995

Ti-6Al-4V alloy are widely used in chemical and aircraft industries for their good corrosion resistance and high strength to weight ratio. Surface alloying of Ti alloy by $CO_2$ laser is able to produce few hundred micrometers thick TiN surface-alloyed layer with high hardness on the substrate very simplely by injecting reaction gas($N_2$) into a laser-generated melt pool and adjust the hardness to the specific requirements of the individual application by changing of laser processing parameters. This research has been investigated the effect of such parameters on TiN surface-alloying of Ti-6Al-4V alloy by $CO_2$ laser. The maximum hardness of TiN surface-alloyed zone waw obtained by injecting 100% $N_2$ gas and it was decreased as the amount of $N_2$ gas in Ar and $N_2$ gas mixture was decreased. As scanning speed was increased, the hardness and depth of TiN surface-alloyed zone was decreased at constant laser power. The surface hardness after double scanning laser treatment is higher than that of single scanning. At constant laser power, the surface roughness is increased after the surface alloying if laser scanning speed is decreased.

• The Journal of Korean Medicine
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• v.16 no.1 s.29
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• pp.184-197
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• 1995

After 45 patients examined as to the result of medical treatment among the ones who came to Dept. of Pain Clinic, Oriental Medical Hospital, Chunju Woosuk University complaining low back pain chiefly from Dec/19/1994 to Feb/7/1995 for 50 days or so were observed clinically, the results were obtained as follows: 1. In duration of the case history, acute stage(37.8%) was the most predominant, and subacute stage(35.6%) and chronic stage(26.7%) were revealed in turn. 2. In opinions of radiation, Spondylosis(26.7%) was the most predominant, Scoliosis(15.6%) and HIVD(11.1%) were revealed in order, and 3 cases were revealed to be negative. 3. In the radiating pain of the lower limb, the radiating pains of the left lower limb were the most predominant and those of the right lower limb and those of both lower limbs were revealed in turn. By the way, 31.1% of patients didn't suffer from the radiating pain of the lower limb. 4. In the grade of the seriousness of subsective symptom, Grade 2(66.7%) was the most predominant, and Grade 3, Grade 4, and Grade 1 followed it in order. 5. In the period of the treatments of medi-acupuncture, 2-5 day treatments(31.1%) were major and 6-10 day treatments(26.7%), 16-20 day treatments(11.1%), 26-30 day treatments(11.1%), over 31 day treatments(11.1%), 11-15 day treatments(4.4%), and 21-25 day treatments(4.4%) followed it by turns. Thus 2-10 day treatments are 57.8% and under 30 day treatments are 57.8% of all. 6. In the frequency of use of each medi-acupuncture, V was most frequency used in 41 cases(91.1%), and 11 cases of HN(24.4%), 8 cases of MOK(17.8%), 4 cases of OK(8.9%), 2 cases of B(4.4%), and a case of I(2.2%) were revealed in turn. 7. In the effect of treatments, 10 cases(22.2%) were excellent, 25 cases(55.6%) were good, 5 cases(11.1%) were fair, and 5 cases(11.1%) were poor. As the result, 88.9% of all changed for the better and all of these were improved within the third trial. 8. The effect of the treatments per durations was 100% in acute stage, 93.8% in subacute stage, and 66.7% in chronic stage. According to that, it was reavealed that the rate of treatments decreased as it came near to the chronic stage. 9. The effect of treatments per radiating pains was 87.5% in the radiating pains of the left lower limb, 81.8% in those of the right lower limb, 100% in those of both lower limbs, and 92.9% in case that patients have no radiating pains. So in the rate of treatments on radiating pains of the lower limbs, the case of both sides or no radiating pains was higher than that of one side. 10. In the effect of treatments per the condition of patients, Grade 4 showed 100% of improvement, Grade 3 showed 90.9% of improvement, Grade 2 showed 86.7% of improvement, and Grade 1 showed 100% of improvement. 11. In the effect of treatments per contents of treatments, the group treated with medi-acupuncture therapy, herb medication therapy, acupuncture therapy, and physiothrapy at the same time(Group 1) showed 100% of improvement, the group treated with medi-acupuncture therapy, acupuncture therapy, and physiotherapy simultaneously(Group 2) showed 73.7% of improvement, and the group treated with medi-acupuncture therapy and acupuncture therapy at the same time(Group 3) showed 100% of improvement. 12. 2-5 day treatments showed 78.6% of improvement, 6-10 day treatments showed 91.7% of improvement, and over 31 day treatments showed 100% of improvement. As the result, genarally the longer the period of treatment was, the better the effect of treatment was. 13. When only V was used, the rate of treatment was 96.2%. When only HN was used, the rate of treatment was 100%. When only MOK was used, the rate of treatment was 100%. When V and HN were used at the same time, the rate of treatment was 33.3%. When V and MOK were used at the same time, the rate of treatment was 100%. When V and OK were used at the same time, the rate of treatment was 100%. When V, HN, and MOK were used at the same time, the rate of treatment was 100%. When V, OK, and MOK were used at the same time, the rate of treatment was 100%. When V, MOK, and B were used at the same time, the rate of treatment was 100%. When V, HN, OK, and I were used at the same time, the rate of treatment was 100%. When V, HN, and B were used at the same time, the rate of treatment was 100%.

• Journal of Korea Water Resources Association
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• v.49 no.11
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• pp.923-930
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• 2016

This study was to evaluate the stream depletion from groundwater pumping in shallow aquifer using the Hunt's analytical solution (2009) which considers a two-layer leaky aquifer-stream system. From the total 2,187 cases of simulations with combinations of various aquifer and stream properties, the streamflow depletion rates divided by the groundwater pumping rate showed the low values when the stream depletion factor (SDF) is higher than 1,000-10,000, and was more sensitive to the aquitard hydraulic conductivity than the streambed hydraulic conductivity. The comparison of the Hunt's solution (2009) with the Hunt's solution (1999) of a single layer aquifer indicated that the maximum difference between the dimensionless stream depletions calculated by using both solutions is above 0.3, and the stream depletion is significantly affected by the hydraulic properties of the $2^{nd}$ layer as the SDF of the first layer increases. The Hunt's solution (2009) was applied to the real shallow groundwater well that is located in Chunju-Si, and the results revealed that the groundwater pumping has significant effects on streamflow in a short period of time, showing that the dimensionless stream depletion exceeds 0.8 within a few days. It was also found that the shallow groundwater pumping effects on stream depletion are highly dependent on the stream-well distance for the locations with high hydraulic diffusivity of $1^{st}$ layer and low vertical leakance between $1^{st}$ and $2^{nd}$ layers.

• Journal of the Korean Geosynthetics Society
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• v.16 no.1
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• pp.1-8
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• 2017

Displacement of dams by various instrumentations has been monitored for its safety management and analyzing the behavior after a dam collapse accident. However, unknown displacement of dam has frequently been occurred and it's difficult to analyze behavior of dams more accurately. In this study, improvement of reliabilities for displacement of dams measured by a total station was suggested by calibrating the monitoring system. The position of total station was initially measured through 2-3 given points and the coordinate of the total station was considered as an absolute value. Also, base horizontal and vertical angles had not been considered even if they are important factors when displacement was estimated. In this study, location of the total station and variations of base horizontal and vertical angles were investigated during measuring displacements of targeting points. From the results of this study, they are important factors which are affecting measurements of dam displacements. Before the calibrating, the displacement at 50 m from total station was ${\pm}20mm$. After the calibrating, the displacement was decreased by ${\pm}5mm$.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.148-165
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• 2015

Iron was one of the most influential factors for formation and development of ancient countries. The diffusion of ironware had increased agricultural productivity and brought about military technical revolution. Needless to say, the rise and fall of the countries depended on the possession of stable iron production. Raw materials and fuels are the key factors for mass production of iron and a transportation route is essential to supply the goods. Jungwon area satisfies the three factors. There are many iron manufacture sites such as Jincheon Seokjang-ri Gusan-ri, and Chunju Chilgeum-dong Tangeumdae earthen ramparts in the Jungwon area. In order to study the ancient iron manufacture technique, reconstitution experiment was carried out using restored furnace which was made based on the Jincheon Seokjang-ri B-23 furnace. Some notable results were identified with the experiment as in the followings. Firstly, a roasting process has a connection with the decrease of hardness of the iron ore. Secondly, melting of the blast pipe as well as the formation of product within the furnace had a crucial effect on the cessation of the experiment. Thirdly, reduced iron in various locations within the furnace prove that there was enough reducing environment during the working. Not only melting point but also properties of iron can vary depending on the carbon contents. For the reason, formation of approximate environment in which iron can react to the chalcoal is the most important factor in terms of iron manufacture.

• Korean Journal of Heritage: History & Science
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• v.51 no.4
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• pp.224-233
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• 2018

Thirty-three Early Iron Age bronzes at the sites of Hoam-dong in Chungju and Cheongsong-ri in Buyeo were investigated in order to study the manufacturing technique and the provenance of lead. Chemical analysis using X-ray fluorescence showed that 33 bronzes consist of copper(Cu), tin(Sn) and lead(Pb) served as major elements. Major and minor elemental analyses by EPMA were performed on two mirrors and 2 weapons of the bronzes investigated. The results shows that bronze mirrors from Chungju and Buyeo were high-tin bronzes(> 30 wt%). And 20% of tin and 5% of lead were founded in bronze weapons. Iron, zinc, arsenic, silver, nickel, sulfur and cobalt detected in four bronzes as minor and trace elements. The four bronzes were alloyed considering their function and were not heat treated after casting due to their high tin content. Lead isotope analysis using TIMS indicates that thirty-three bronzes were distributed southern Korea peninsula except Zone 1. As a result, lead raw materials came from various regions in Korean Peninsula not from Gyeongsang-do regions. The manufacturing techniques of bronze ware generalized at this age, and bronze was produced in various sites using raw materials from various sources.

• Journal of Preventive Medicine and Public Health
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• v.3 no.1
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• pp.97-110
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• 1970

This survey was conducted to evaluate not only the present status of health center directors-their personal histories, their will to private practice in the future, their responses to governmental policies, -but also the distribution of doctorless myons, budget and subsidy, and director's opinions to the enhancement of health center activities. This survey questioned 116 health center directors and 16 health personnel from August to October of 1970 and obtained the following results; 1) The average ages of directors of kun, city, and total health centers were $43.2{\pm}7.8,\;42.1{\pm}7.7,\;and\;42.9{\pm}10.3$ respectively. 2) The average family sizes of directors of kun, city, and total health centers were $5.6{\pm}2.7,\;5.6{\pm}2.1,\;and\;5.6{\pm}2.6$ respectively. 3) Directors holding M. D. degrees were 79.3%, those holding qualified M. D. degrees ('approved director') were 20.7%. 4) M. P. H., M. S., and Ph. D. holders were 6.0%, 6.1%, and 4.3% respectively. 5) The average duration of present directorship in kun and city were 30.2 months and 20.4 months respectively. 6) The majority of directors had been employed in related fields before assuming current position : directorship at other health center 26.7%, army 22.4%, health subcenter 21.6%, private practice 19.0%. 7) Average length of directorship is 41.8 months. Average length of public health career, including health subcenter and present position, is 56.5 months. 8) Both rural and urban experience in health centers for regular directors is 16.3% and for approved directors, 12,5%. A total of 15.5% of all survey directors had experience in both rural and urban health center. 9) A total of 70.7% of health center directorships were staffed by local doctors. 10) Nearly 40% wanted to quit the directorships within 3 years and 60.3% had already experienced private practice. 11) Of the regular directors 17.4% felt strongly about devoting their lives to public health fields, but only 4.1% of the approved approved directors felt so. 12) There wire 432 doctorless myons among 996 respondent myons and 4.5 doctorless myons per kun. 13) The percentage of doctorless myon by Province are as follows, Cholla buk-do 57.2%, Cholla nam-de 55.0%, Kyungsang nam-do 52.0%, Kyungsang buk-do 49.7%, Chungchong but-do 42.4%, Kyonggi-do 32.9%. Cheju-do 30.8%, Kangwon-do 25.8%. 14) Two thirds of health critters have experienced the abscence of the director for a certain period since 1966 and the average span of the abscence was 18.2 months. 15) The percentage of doctorless myons increased proportionally with the span of the director's abscence. 16) The average budgets of health centers, kun, city and ku, were $W15.03\;million{\pm}W4.5\;million,\;W22.03\;million{\pm}W17.80\;million,\;W13.10\;million{\pm}W7.9\;million$ respectively. 17) Chunju city had the highest health budget per capita(W344) while Pusan Seo ku had the lowest(W19). 18) Director's medical subsidies are W30,000-50,000 in kun, and roughly W20,000 in city. 19) The older of priority in health center activities is T.B. control(31.1%), Family Planning and M. C. H.(28.0%), prevention of acute communicable disease and endemic disease (18.2%) and clinical care of patients(14.3%). 20) Nearly 32% opposed in principle the governmental policy of prohibiting medical doctors from going abroad. 21) Suggestions for immediate enhancing the position of director of health centers and subcenters: (1) Raise the base subsidy (48.2%), (2) Provide more opportunities for promotion (20.7%), (3) Exemption from army services(12.1%), (4) Full scholarship to medical students for this purpose only (7.8%). 22) A newly established medical school was opposed by 56.9% of the directors, however 33.6% of them approved. 23) Pertaining to the division of labor in Medicine and Pharmacy, the largest portion (31.9%) urged the immediate partial division of antibiotics and some addictive drugs to be given only by prescription. 24) More than half wanted a W70,000 level for the director's medical subsidies, white 36.2% stated W50,000. 25) Urgently needed skills in the kun are clinical pathologist (38.6%) and doctor (health center director) (25.5%); while in the city nurse (37.1%), doctors(clinical)(31.4%) and health educators(14.4%) are needed. 26) Essential treatment for the better health center administration; raising the base subsidy (22.7%), obtaining the power of personal management (19.3%) and the establishment of a Board of Health (14.3%). etc.