• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.174-175
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• 2012

(In, Ga) N-based III-nitride semiconductor materials have been viewed as the most promising materials for the applications of blue and green light emitting devices such as light-emitting diodes (LEDs) and laser diodes. Although the InGaN alloy can have wide range of visible wavelength by changing the In composition, it is very hard to grow high quality epilayers of In-rich InGaN because of the thermal instability as well as the large lattice and thermal mismatches. In order to avoid phase separation of InGaN, various kinds of structures of InGaN have been studied. If high-quality In-rich InGaN/GaN multiple quantum well (MQW) structures are available, it is expected to achieve highly efficient phosphor-free white LEDs. In this study, we proposed a novel InGaN double hetero-structure grown on GaN nano-pyramids to generate broad-band red-color emission with high quantum efficiency. In this work, we systematically studied the optical properties of the InGaN pyramid structures. The nano-sized hexagonal pyramid structures were grown on the n-type GaN template by metalorganic chemical vapor deposition. SiNx mask was formed on the n-type GaN template with uniformly patterned circle pattern by laser holography. GaN pyramid structures were selectively grown on the opening area of mask by lateral over-growth followed by growth of InGaN/GaN double hetero-structure. The bird's eye-view scanning electron microscope (SEM) image shows that uniform hexagonal pyramid structures are well arranged. We showed that the pyramid structures have high crystal quality and the thickness of InGaN is varied along the height of pyramids via transmission electron microscope. Because the InGaN/GaN double hetero-structure was grown on the nano-pyramid GaN and on the planar GaN, simultaneously, we investigated the comparative study of the optical properties. Photoluminescence (PL) spectra of nano-pyramid sample and planar sample measured at 10 K. Although the growth condition were exactly the same for two samples, the nano-pyramid sample have much lower energy emission centered at 615 nm, compared to 438 nm for planar sample. Moreover, nano-pyramid sample shows broad-band spectrum, which is originate from structural properties of nano-pyramid structure. To study thermal activation energy and potential fluctuation, we measured PL with changing temperature from 10 K to 300 K. We also measured PL with changing the excitation power from 48 ${\mu}W$ to 48 mW. We can discriminate the origin of the broad-band spectra from the defect-related yellow luminescence of GaN by carrying out PL excitation experiments. The nano-pyramid structure provided highly efficient broad-band red-color emission for the future applications of phosphor-free white LEDs.

• The Journal of Fisheries Business Administration
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• v.15 no.1
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• pp.131-153
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• 1984

Fishery resources are still abundant compared with other resources and the possibility of exploitation is probably great. The Korean fishery industry has grown remarkably since 1957, and Korea is ranked as one of the major fishery countries. Its of fishery products reached the 9th in the world and the value of exports was 5th in 1982. But recently a growth rate has slowed down, due to the enlargement of territorial seas by the declaration of the 200 mile, Exclusive Economic Zone, the tendency to develop fishery resources strate-gically in international bargaining, the change in function of the international organizations, the expansion of regulated waters, the illegal arrest of our fishing boats, the rapid rise in oil prices, and the fall in fish prices, the development of fishery resources as a symbol of nationalism, the fishing boats decreptitude, the rise of crew wages, regulations on fishing methods, fish species, fishing season, size of fish, and mesh size, fishing quotas and the demand of excessive fishing royalties. Besides the the obligation of coastal countries, employing crews of their host countries is also an example of the change in the international environment which causes the aggravation of foreign profit of fishing firms. To ameliorate the situation, our Korean fishery firms must prepare efficient plans and study systematically to internationalize themselves because such existing methods as conventional fishing entry and licence fishing entry are likely to be unable to cope with international environmental change. Thus, after the systematic analysis of the problem, some new combined alternatives might be proposed. These are some of the new schemes to support this plan showing the orientation of our national policy: 1. Most of the coastal states, to cope with rapid international environmental change and to survive in the new era of ocean order, have rationalized their higher governmental structure concerning the fishery industries. And the coastal countries which are the objectives of our expecting entry, demand excessive economic and technical aid, limit the number of fishing boats’entry and the use of our foreign fishing bases, and regulate the membership of the international fishery commissions. Especially, most of the coastal or island countries are recently independent states, which are poorer in national budget, depend largely on fishing royalties and licence entry fees as their main resources of national finance. 2. Alternatives to our entry to deep sea fishing, as internationalization strategies, are by direct foreign investment method. About 30 firms have already invested approximately US $ 8 million in 9 coastal countries. Areas of investment comprise the southern part of the Atlantic Ocean, the Moroccan sea and five other sea areas. Trawling, tuna purse seining and five other fields are covered by the investment. Joint-venture is the most prominent method of this direct investment. If we consider the number of entry firms, the host countries, the number of seas available and the size of investment, this method of cooperation is perhaps insufficient so far. Our fishery firms suffer from a weakness in international competitive ability, an insufficiency of information, of short funds, incompetency in the market, the unfriendliness of host coastal countries, the incapability of partners in joint-ventures and the political instability of the host countries. To enlarge our foreign fishing grounds, we are to actively adopt the direct investment entry method and to diversity our collaboraboration with partner countries. Consequently, besides proper fishing, we might utilize forward integration strategies, including the processing fied. a. The enterprise emigration method is likely to be successful in Argentina. It includes the development of Argentinian fishing grounds which are still not exploited in spite of abundant resources. Besides, Arentina could also be developed as a base for the exploitation of the krill resources and for further entries into collaboration with other Latin American countries. b. The co-business contract fishing method works in American territorial seas where American fishermen sell their fishery products to our factory ships at sea. This method contributes greatly to obtaining more fishing quotas and in innovation bottom fishing operation. Therefore we may apply this method to other countres to diffuse our foreign fishing entry. c. The new fishing ground development method was begun in 1957 by tuna long-line experimental fishing in the Indian Ocean. It has five fields, trawling, skipjack pole fishing and shrimp trawling, and so on. Recently, Korean fisheries were successful in the development of the Antarctic Ocean krill and tuna purse seining. 3. The acceleration of the internationalization of deep sea fishing; a. Intense information exchange activities and commission participation are likely to be continues as our contributions to the international fishery organizations. We should try to enter international fishery commissions in which we are not so far participating. And we have to reform adequately to meet the changes of the function of the international commissions. With our partner countries, we ought to conclude bilateral fishery agreements, thus enlarging our collaboration. b. Our government should offer economic and technical aids to host countries to facilitate our firms’fishery entry and activities. c. To accelerate technical innovation, our fishery firms must invest greater amount in technical innovation, at the same time be more discriminatory in importing exogeneous fishery technologies. As for fishing methods; expanded use of multi-purpose fishing boats and introduction of automation should be encuraged to prevent seasonal fluctuations in fishery outputs. d. The government should increases financial and tax aid to Korean firms in order to elevate already weak financial structure of Korean fishery firms. e. Finally, the government ought to revise foreign exchange regulations being applied to deep sea fishery firms. Furthermore, dutes levied on foreign purchaed equipments and supplies used by our deep sea fishing boats thould be reduced or exempted. when the fish caught by Korean partner of joint-venture firms is sold at the home port, pusan, import duty should be exempted.

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.80-84
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• 2001

Purpose : To evaluate the clinical and radiological results of posterior cruciate ligament reconstruction(PCL) by tibial inlay technique. Materials and Methods : Twenty four patients(25 cases), who underwent reconstruction of posterior cruciate ligament by tibial inlay technique and were followed up for at least 2 years, were reviewed retrospectively. Mean age at operation was 35 years and mean period of follow up was 34 months. Clinically Lysholm knee socre, posterior drawer test and step off sign were evaluated. Instrumented posterior laxity test with $Telos^{\circledR}$ device(Telos stress device; Austin & Associates, Inc., Polston, US) was performed. Results : Lysholm knee score was improved from 56.9 points preoperatively to 94.6 points at fellow up. Posterior drawer test showed grade II instability in 1 case, grade III in 18 and Grade IV in 6 preoperatively and improved to grade I In 12, grade II in 10 and grade III in 3 at follow up. Step off signs were changed from -10mm in 6 cases, -5mm in 18 and flush in 1 preoperatively to -5mm in 3, flush in 10 and +5mm in 12 at follow up. Side to side difference of instrumented posterior laxity test was improved front 13.6mm preoperatively to 4.3mm at follow up. Conclusions : PCL reconstruction by tibial inlay technique is considered to be a good treatment method to restore posterior stability of the knee, which could result in satisfactory clinical and radiological results at more than 2 years' follow up.

• Korean Journal of Environmental Biology
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• v.35 no.2
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• pp.105-115
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• 2017

The present study is to understand the Bongseonsa stream in the National Arboretum fish fauna variation through comparison with historical data and to evaluate the stream health situated. We performed investigations over three times from April to September 2015. In the survey, 2,960 individuals which belonging to 22 species, 8 families were collected. Dominant species by number was Zacco platypus and subdominant species was Zacco koreanus. Seven Korean endemic species (Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Koreocobitis rotundicausata, etc) were observed and showed a ratio of 36.4%. The community analysis revealed that the structure of fish community in the study sampling sites was instability in having dominance 0.79 (${\pm}0.15$), diverse 1.21 (${\pm}0.60$), evenness 0.58 (${\pm}0.15$) and species richness 1.49 (${\pm}0.83$). The values in the Qualitative Habitat Evaluation Index (QHEI) was averagely 122.9 (${\pm}44.8$) in the Bongseonsa stream and this was showed to have favorable habitat surroundings. As a result of tolerance guild analysis, the total number of sensitive species and intermediate species were higher than tolerant species. Analysis was divided into A and B two groups of fiducial 12.25% in Cluster analysis degree of similarity between study sampling sites. Fish Assessment Index (FAI) was rated A and B grade in Bongseonsa stream that stream health showed favorable. However Wangsuk stream as a urban stream rated C grade and analysed the lowest grade in the whole study sampling sites. There was high correlation beteween FAI and various indexes, dominance, diverse, evenness and sensitive species and intermediate species.

• Journal of muscle and joint health
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• v.5 no.2
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• pp.238-252
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• 1998

Reumatic arthritis is a disease with joint pain being one of the key symptoms. The patient suffers from the pain, stiff sensation and edema due to the inflammation taking Place In one or more joints. Accompanying these problems are fatigue, unusual exhaustion, fever, tachycardia and weakness. Inaddition, joints are often deformed and muscles shrink along with the progress of edema, coupled with depression and psychological instability resulting from the loss of the mobile function and limitations on the daily life. Some patients become fed up with the long and hard flight with the disease and just give up, which aggravates the symptoms. Others come to the hospital only when the conditions have become serious. We need to prevent these and guide the patients in the right direction. Against this backdrop, this study aims to look into the relations between the knowledge on the part of the patients together with their feeling of self-efficacy and the compliance. The results are expected to help the patients improve their life, In addition to providing useful materials for setting up appropriate plan for nursing intervention. The study was conducted by distributing questionnaire to 88 patients selected from the out-patient department of a university hospital in Inchon, from April 6 to 27, 1998. The following tools were used the yardstick of self-efficacy, developed in 1997 by the Society for the Health of Rheumatism Patients, was used for measuring the levels of knowledge and the feeling of self-efficacy. The degree of compliance was measured by the data collected from documents in addition to the results of the analysis of the interviews with the patients. The reliability of the tools was confirmed. In the analysis, the general characteristics were expressed in figures and percentages. The levels of knowledge, feeling of self-efficacy, and compliance were expressed in the average values and standard deviations. The relations among the variables following the general characteristics were analysed by the t-test and one-way ANOVA. The Pearson correction coefficient was used for the analysis of factors. Multiple-loop analysis was used to identify the variables affecting the compliance. The following are the results of this study. 1. Among the 88 patients, 18 were men and the remaining 70 were women, with a ratio 1 : 3.87. Regarding the age groups, 23 were between 50 and 59 years old, with those between 50 and 69 accounting for 51.1% of the total. High school graduates or higher amounted to 58%. Religious patients was 67% or 59 persons. Fifty nine percent were unemployed, and 58.3% (49 persons) had two children or fewer. The period of suffering from rheumatism varied between 2 months and IS years, with 70% less than years. 2. The average figure In relation to the of knowledge was 17.63 points over 30 or 58. 76%, which means a medium level. 3. The average figure of the feeling of self-efficacy was 60.06 points. 4. The level of compliance was 3.26, which was above average. 5. The relation between the feeling of self-efficacy and compliance showed an "r" value of 0.37, which was significant. It means that the higher the feeling, the greater the compliance points. 6. The analysis of the knowledge level revealed that the difference is found only between the college graduates and junior-high graduates or lower. 7. The feeling of self-efficacy varied along with the age and education level. 8. The general characteristics of patients as discussed above did not show significant difference with the compliance. 9. Regarding the elements influencing the compliance, the number of children, period of suffering, income, age, feering of self-efficacy, knowledge, and compliance had 54% of significance. In conclusion, rheumatism victims can lead a better life if they are appropriately educated, based on efficient training program from the early days of the disease ; if they become able to manage themselves thanks to the training ; and if they are helped by a program focusing on the increase of the feeling of self-efficacy aimed at changing patient's behavior.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.1
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• pp.1-9
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• 2000

Purpose : Spine is one of the most common sites of the metastatic bone tumors. Conservative management such as chemotherapy or radiotherapy has been preferred in most cases. However, the neurologic deficit has not been usually improved, and the quality of life was poor. The purpose of this study was to show the efficacy of the surgical treatments for metastatic spinal tumors in terms of postoperative improvements of neurologic deficit and survival time. Materials and Methods : Authors have reviewed the literatures and analyzed 14 patients of metastatic spinal tumors who were received operative treatments between August 1991 and June 1999 at the our department of orthopaedic surgery. Results : The most frequent primary tumor was breast cancer in women and lung cancer in men. The thoracic region was the most common site. There was a preponderance of females over males, and the age ranged between 4th and 8th decade. The indications of surgical treatment comprised instability, progressive neurologic findings, resistance to radiotherapy, pathological fracture, long life expectancy( >6weeks), isolated metastasis and need for pathological diagnosis. The degree of preoperative neurological deficit might influence on the improvement of clinical symptoms after surgery. Conclusion : The surgical treatment reduced the neurological deficit and pain regardless of the operative methods. In the early stage of neurological deficit, the surgical treatment was important for better prognosis. Recently early active operative treatment was performed for metastatic spinal tumor to minimize the intractable pain and to prevent the progression of the neurologic deficit. Early intervention can improve the quality of life and long term survival.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.2
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• pp.53-60
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• 2000

Purpose : The purpose of the current study is to evaluate the functional and oncologic results of the limb salvage surgery with intramedullary nailing and cementization in malignant bone tumors of the proximal humerus. Materials and Methods : We reviewed 18 cases of limb salvage surgery of resection and reconstruction with an intramedullary nail and cement-molded humeral head for the malignant bone tumors of the proximal humerus, which performed between August, 1992 through the April, 1998. The diagnoses included the osteosarcoma in 7 patients, chondrosarcoma in 3, the recurrent giant cell tumor in 3, metastatic tumor in 3, multiple myeloma in one patient and the one patient with malignant fibrous histiocytoma. The mean age at the time of surgery was 38 years(range, 15-73 years). The mean follow-up period was 26 months(range, 6-67 months). Results : Average functional score by ISOLS evaluation system was 21.1(70.3%). There were 3 local recurrences and 5 distant metastases. There were one case of shoulder instability and one case of deep infection. The seven patients are continuously disease free state and seven patients are alive with disease. Four patients died from the disease. Conclusion : The limb salvage surgery with intramedullary nailing and cementization in the bone tumors of the proximal humerus may be considered an option for the malignant bone tumors of the proximal humerus in selected patients.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.33-49
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• 2016

The study area, located in Sinam-ri, Ulsan, in the southeastern part of the Korean Peninsula, is mainly composed of hornblende granite (ca. 65 Ma). Fracturing and reactivation of a fault striking ENE-WSW was strongly controlled by the intrusion of a mafic dyke (ca. 44 Ma), which behaves as a discontinuity in the mechanically homogeneous pluton, increasing the instability of the basement in this area. A geometric and kinematic study undertaken to interpret the faults and fractures was performed in a trench excavated almost perpendicular to the orientation of the dyke. The analysis of structural elements, such as dykes, veins, and faults, is used to infer the deformation history and to determine the paleostress orientations at the time of formation of the structures. The deformation history established based on this analysis is as follows: (1) NNE-SSW, E-W, ENE-WSW, and NE-SW trending fractures had already developed in the pluton before dyke intrusion; (2) felsic dykes intruded under conditions of σ_Hmax oriented N-S and σ_Hmin oriented E-W; (3) mafic dykes intruded under conditions of σ_Hmax oriented E-W and σ_Hmin oriented N-S; (4) dextral reactivation of the main fault associated with the development of hydrothermal quartz veins under conditions of σ_Hmax oriented E-W and σ_Hmin oriented N-S; (5) sinistral reactivation of the main fault and high-angle normal faults under conditions of σ_Hmax oriented NE-SW and σ_Hmin oriented NW-SE; and (6) dextral reactivation of the main fault and NE-SW low-angle reverse faults under conditions of σ_Hmax oriented NW-SE and σ_Hmin oriented NE-SW. These results are consistent with the tectonic history of the Pohang-Ulsan block in the southeastern part of the Korean Peninsula, and indicates the tectonic deformation of the southern area of the Ulsan fault bounded by Yangsan fault was analogous to that of the Pohang-Ulsan area from the Cenozoic. This work greatly aids the selection of sites for critical facilities to prevent potential earthquake hazards in this area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.18 no.1
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• pp.1-12
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• 2013

Acoustic backscatter profiles were measured by Eco-sounder along an east-west section in the mid-eastern Yellow Sea and at an anchoring station in the low salinity region off the Keum River estuary in September 2012, with observing physical water property structure by CTD. Tidal front was established around the sand ridge developed in 50 m depth region. Internal waves measured by Eco-sounder during low tide period in the eastern side of the sand ridge were nonlinear depression waves with wave height of 15 m and mean wavelength of 500 m. These waves were interpreted into tidal internal waves that were produced by tidal current flowing over the sand ridge to the southeast. When weakly non-linear soliton model was applied, propagation speed and period of these internal depression wave were 50 m/s and 16~18 min. Red tides by Dinoflagelates Cochlodinium were observed in the sea surface where strong acoustic scattering layer was raised up to 7 m. Hourly CTD profiles taken at the anchoring station off the Keum River estuary showed the halocline depth change by tidal current and land-sea breeze. When tidal current flowed strongly to the northeast during flood period and land-breeze of 7 m/s blew to the west, the halocline was temporally raised up as much as 2 m and acoustic profile images showed a complex structure in the surface layer within 5-m depth: in tens of seconds the declined acoustic structure of strong and weak scattering signals alternatively appeared with entrainment and intrusion shape. These acoustic profile structures in the surface mixed layer were observed for the first time in the coastal sea of the mid-eastern Yellow Sea. The acoustic profile images and turbidity data suggest that relatively transparent low-layer water be intruded or entrained into the turbid upper-layer water by vertical shear between flood current and land breeze-induced surface current.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.121-127
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• 1985

This study was designed to gain practical data on the use of soil conditioners for more efficient water managements and to establish the optimum levels of structural properties for soil conditioning. A sandy loam and a silt loam soil were each treated with two different soil conditioners, hydrophobic Bitumen or hydrophilic Uresol. The perspex tube 34 cm long were packed homogeneously with air dried soil up to 2 cm below the top, then covered over 2 cm of treated or untreated aggregates. The infiltration rate into the soil columns was measured under simulated rainfall condition. The evaporation study was carried out in the wind tunnel, and the changes of soil moisture distribution of the columns following and during the evaporation were determined by a gamma ray scanner. The infiltration rate of water into the soil column was increased to 18.7-50.8% by the Uresol treatment but it was decreased to less than 25% of control by the Bitumen treatment. Evaporation was decreased to 22.0-68.1% by the Bitumen treatment and to 38.7-68.4% by the Uresol treatment. The water use efficiency of Uresol treated column was increased to more than twice as much as that of untreated soil. Aggregate stability and wetting angle were related to water infiltration and evaporation. A positive and highly significant logarismic relationship was found between the infiltration rate and stability index-wetting angle, evaporation rate and instability index-wetting angle. It was considered that the structural stability is more important than wetting angle. This is true because the structural stability is always positively correlated to water saving, however wettability is positively correlated to the infiltration, and negatively correlated to water saving during the evaporation.