• 한국발생생물학회지:발생과생식
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• 제1권1호
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• pp.9-24
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• 1997

To investigate the process of spermiogenesis of the Korean eastern Daubenton's bat, Myotis daubentonii ussuriensis, the testis obtained from mature male bats was studied by transmission electron microscope and were based on the variety and diagnostic characters of cell organells. The results obtained from the present study are as follows. According to the differentiation of the cell organells, the spermiogenesis of the Korean eastern Daubenton's bat, M. d. ussuriensis, was divided into Golg, cap, acrosome, maturation and spermiation phases. Besides, these Golgi, cap, acrosome, and maturation phase were subdivided into the steps of early and late phases repectively and matruation phase was subdivided into step of early, mid and late phases. Therfore, the spermiogenesisof M. d. ussuriensis has been divided into a total of 11 phases. The chromatin granules began to condense at the early cap phase, regularized at the acrosome phase, and a perfect nucleus of sperm was formed at the maturation phase. The chromatoid body was occurred in the upper cytoplasm of nucleus at the early Golgi phase, and it was accurred the posterior cytoplasm of the nucleus at the early maturatio phase. The formation of sperm tail began to be develop in the early golgi phase, and completed at the spermiation phase. The fiber structure of middle piece was consisted of nine outer doublets and two central singlet microtubules and Nos. 1, 5, 6 and 9 in the outer dense were larger than the others(2, 3, 4, 7, 8).

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.719-723
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• 2013

Nitrification in wastewater treatment emits a significant amount of nitrous oxide ($N_2O$), which is one of the major greenhouse gases. However, the actual mechanism or metabolic pathway is still largely unknown. Selective nitrification inhibitors were used to determine the nitrification steps responsible for $N_2O$ emission with activated sludge and enriched nitrifiers. Allylthiourea (86 ${\mu}M$) completely inhibited ammonia oxidation and $N_2O$ emission both in activated sludge and enriched nitrifiers. Sodium azide (24 ${\mu}M$) selectively inhibited nitrite oxidation and it led to more $N_2O$ emission than the control experiment both in activated sludge and enriched nitrifiers. The inhibition tests showed that $N_2O$ emission was mainly related to the activity of ammonia oxidizers in aerobic condition, and the inhibition of ammonia monooxygenase completely blocked $N_2O$ emission. On the other hand, $N_2O$ emission increased significantly as the nitrogen flux from nitrite to nitrate was blocked by the selective inhibition of nitrite oxidation.

• 한국응용과학기술학회지
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• 제22권2호
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• pp.106-115
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• 2005

Bio-diesel as fatty acid methyl ester was derived from such oils as soybean, peanut and canola oil by lipase catalyzed continuous trans-esterification. So the activation of lipase(Novozym - 435) was kept to be up to 4:1, the limiting molar ratio of methanol to oil under one-step addition of methanol due to the miscibility of oil and methanol through the static mixer for 4hrs and the elimination of glycerol on the surface of lipase by 7wt% silica gel. Therefore the overall yield of fatty acid methyl ester from soybean oil appeared to be 98% at 50$^{\cdot}C$ of reaction temperature under two-steps addition of methanol with 2${\times}$2:1 of methanol to oil molar ratio at an interval of 5.5hrs, 7wt% of lipase, 24 number of mixer elements, 0.2ml/min of flow rate and 7wt% of silica gel.

• 한국안전학회지
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• 제24권5호
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• pp.63-68
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• 2009

The urgent VAI method development is required since "The Act of Physical Protection and Radiological Emergency that is established in 2003" requires an evaluation of physical threats in nuclear facilities and an establishment of physical protection in Korea. The VAI methodology is developed to (1) make a sabotage model by reusing existing fire/flooding/pipe break PSA models, (2) calculate MCSs and TEPSs, (3) select the most cost-effective TEPS among many TEPSs, (4) determine the compartments in a selected TEPS as vital areas, and (5) provide protection measures to the vital areas. The developed VAI methodology contains four steps, (1) collecting the internal level 1 PSA model and information, (2) developing the fire/flood/pipe rupture model based on level 1 PSA model, (3) integrating the fire/flood/pipe rupture model into the sabotage model by JSTAR, and (4) calculating MCSs and TEPS. The VAT process is performed through the VIPEX that was developed in KAERI. This methodology serves as a guide to develop a sabotage model by using existing internal and external PSA models. When this methodology is used to identify the vital areas, it provides the most cost-effective method to save the VAI and physical protection costs.

• The Korean Journal of Ecology
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• 제25권1호
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• pp.19-24
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• 2002

The traditional Japanese agricultural landscape, In which a set of varied land-use patches functions as a sustainable ecosystem landscape unit, not only provides the local people tilth a stable food supply, but also offers a variety of habitats to many species of wildlife. Therefore, remaining natural habitats including those in the traditional agricultural landscape should be maintained whenever possible. In addition, restoration work should be implemented in areas where the natural habitat has been destroyed or severely degraded by human activities. This basic approach to the natural environment is a combination of maintenance and restoration. Types of maintenance and restoration can be classified into three categories according to the countermeasures employed: preservation, conservation and protection types of maintenance, and improvement, reconstruction and creation types of restoration. Four steps are proposed for ecological restoration and maintenance of a target area: exploration, diagnosis, prescription and care. In this process, a model for approaching the goal is important. One of the most important models should center on the traditional agricultural landscape involving a sustainable farming ecosystem. It is necessary to protect traditional landscapes and ecosystems from the degrading impact of urbanization and industrialization, as well as to enhance efforts at restoration.

• 한국전문물리치료학회지
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• 제5권2호
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• pp.23-38
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• 1998

The objective of this study was to identify the effects of pelvic tilting exercise on gait patterns of hemiplegic patients. The subjects of this study were 31 hemiplegic in- and out-patients of the Rehabilitation Hospital, Yonsei University Medical Center, from September 24, 1997 through November 5, 1997. Pre- and post-treatment change in gait patterns were measured using a ink foot-print. The data were analyzed by the paired t-test, one-way ANOVA, and independent t-test. The findings were as follows: The difference in gait patterns between pre- and post-treatment was statistically significant, with an increase in gait velocity to 7.98 cm/sec post-treatment; an increase in cadence to 7.29 steps/min; a narrowing of the base of support to 1.33 cm; an increase in step length of 3.92 cm on the less affected side and 3.73 cm on the more affected side; an increase in stride length of 5.82 cm on the less affected side and 5.92 cm on the more affected side(statistically not significant in foot angle). In relation to sex, age, cause of stroke, and laterality of paralysis, the difference in gait patterns between pre- and post-treatment was not statistically significant. Where there was no significant difference of the effects of pelvic exercise regarding the degree of spasticity, the presence of a decrease in proprioception, and the duration of treatment. In conclusion, hemiplegic pelvic tilting exercise was found to have transmitting positive effect in improving gait patterns.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권1호
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• pp.24-31
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• 2005

Recently, Platelet rich plasma(PRP) is commonly used because it is now well known that platelets have many functions beyond that of simple hemostasis in aspect of containing autogenous source of several growth factors. It could be responsible for increasing cell mitosis, increasing collagen production, recruiting other cells to the site of injury, initiating vascular ingrowth, and inducing cell differentiation, enhancing bone formation capacity and easily handling to clinician. However, in spite of these clinical advantages, still the theory behind the use of PRP is compelling. This study was to determine preparation techniques used to increase the concentration of platelets and growth factors are all crucial steps in early wound healing of bone graft which may lead to a more rapid and denser bone regenerate. 200 volunteers were sampled and PRP were prepared according to each evaluation item in this study. Higher concentration of platelets have been gained in double centrifugation. 2000 and 2500 rpm showed proper concentration of platelets at first centrifugation and 5000 rpm in second. Timing for 2 minutes was showed good concentration of platelets in high and low centrifugation speed. It was better concentration of platelets in 20 or 30 ml volume during centrifugation. In histomorphologic findings, degrnulated and high concentraion of platelets were found in low centrifugation speed.

• 한국농촌건축학회논문집
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• 제8권1호
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• pp.17-24
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• 2006

The purpose of this study is to provide the systematic report and analysis about Apartment VE application in Design Phase. In this study, the method of VE application is classified into foure groups-changing materials, changing a method of construction, acceptance of new technology, and use of new device. The facts found in this study can be summarized as follows. Application rate of VE is highest in building circumference parts. The main reason would be that there are many applicable factors according to locations, types of work, etc. Parking lots also show similar results with the same reason. It means there are a lot of possibility to adapt value engineering in these steps during the work. So far application of value engineering has been so limited that just small changes of process or method have been tried. One reason is the lack of challenging and the other is some characteristics of construction work which is very difficult to fix after completion. In the future, it would be more efficient to apply new technology and new device in construction work. Though these attempts have been ignored in Korea so far, there are still lots of possibilities to be developed in value engineering.

• 대한소아치과학회지
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• 제24권3호
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• pp.511-517
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• 1997

Tooth discoloration detracts from one's appearance and influences self-image and it is particularly true in children. Therefore, pediatric dentists are required to treat tooth discoloration manifested in children for the normal development of their psycosocial health. Three treatment modalities are currently availabler for the removal of a variety of intrinsic stains from vital teeth. These are enamel microabrasion technique using hydrochloric acid, office bleaching and home bleaching technique with carbamide. Microabrasion technique has several advantages over bleaching in that it is easy to accomplish and does not require multiple office visits or the expensive instruments and the color change seems to be permanent after treatment. The process relies on decalcification, a softening with HCl and then removal of the enamel containing the stain with rubbing. Due to the mechanism of stain removal, this method is indicated for the removal of superficial enamel stains or disc oloration only. We report four successfully treated cases by enamel microabrasion using 15% HCl and pumice. Entire clinical steps are described in detail with some discussions on the outcome.

• 한국추진공학회지
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• 제16권1호
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• pp.16-24
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• 2012

비행 마하수 6으로 운용되며, 지상 정지 추력으로부터 사용이 가능하도록 2단 추진체 개념이 적용된 스크램제트 엔진 비행체에 대한 개념설계를 수행하였다. 1단은 고체로켓을 적용하였으며, 2단은 탄화수소 계열의 연료를 사용하는 스크램제트 엔진을 적용하였다. 개념설계를 위하여 2,000 km의 운용거리와 0.2 톤의 탑재체 무게를 가정하였다. 개념설계의 첫 번째 단계로 3-DOF 코드를 이용하여 비행궤도를 계산하였으며, 계산된 비행궤도를 바탕으로 일차원-비평형 유동 코드와 NASA의 HASA 데이터베이스를 이용하여 스크램제트 엔진에 대한 개념설계를 수행하였다.