분무 열분해에 의한 Ba1-xSrxFe12O19계 자성 미립자의 제조 및 특성 변화

김동현,김광만,김경남,최세영,심인보,이용근 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

Magnetic particles with alternating magnetic field are expected to be useful as thermoseeds in hyperthermic cancer treatment, since they can be targeted and confined to the cancer site. Hard magnetic ferrites such as barium ferrite and strontium ferrite are good candidates for thermoseeds of hyperthermia because of their great hysteresis loss. In order to verify the effect of Sr-substitution to Ba-site, synthesized Ba1-xSrxFe12O19 microspheres with various compositions through spray pyrolysis followed by sol synthesis using barium nitrate, strontium acetate and iron nitrate. Coercive force was increased with increasing substitution amount of Sr whereas magnetic saturation was almost constant. Spherical microspheres with average diameter of 11.7~17.0 ㎛ were produced by spray pyrolysis at 400~1000℃. The mean size was dependent on the pyrolysis temperature and flow rate of carrier gas. In order to obtain a single phase of SrFe12O19 crystal, the spray pyrolyzed spheres were undertaken subsequent heat-treatment above 1000℃. During the subsequent heat-treatment, however, spherical microspheres were agglomerated because of necking between particles. Further study has to be continued working on synthesis of pure SrFe12O19 crystal by means of improvement of pyrolysis temperature scheme and extend the heating period.

국소마취제의 피부수송체를 위한 제제개발 및 평가

조미현,김동우,박용근,지웅길 충남대학교 약학대학 의약품개발연구소 2002 藥學論文集 Vol.17 No.-

For the dermal drug delivery system of local anesthetics (lidocaine HCl, and benzocaine), the drugs were formulated as hydrogel. The experiments of the formulation design were summarized as below, the lipid-water partition coefficients of drugs were evaluated and the vehicles with different concentrations of ethanol, glycerine and various enhancers were prepared for the formulation of hydrogel. After using these vehicles, hydrogel were formulated. The gelling agent was poloxamer 407. The resulting preparations were evaluated using in vitro drug permeation and drug accumulation in hairless mouse skin. The preparations were also evaluated by their viscosity and stability, In addition, using the tail-flick analgesia test, analgesic activity of the gel was compared with that of commercial cream.

납기와 조립가능 시점을 고려한 병렬기계의 스케쥴링을 위한 발견적 해법

이동현,이경근,김재균,박창권,장길상 한국경영과학회 2000 한국경영과학회지 Vol.25 No.2

In this paper, we consider an n-job, non-preemptive and identical parallel machine scheduling problem of minimizing the sum of earliness and tardiness with different release times and due dates. In the real world, this problem is more realistic than the problems that release times equal to zero or due dates are common. The problem is proved to be NP-complete. Thus, a heuristic is developed to solve this problem. To illustrate its suitability, a proposed heuristic is compared with a genetic algorithm for a large number of randomly generated test problems. computational results show the effectiveness and efficiency of proposed heuristic. In summary, the proposed heuristic provides good solutions than genetic algorithm when the problem size is large.

어린이의 저항트레이닝 처방에 영향을 미치는 요인에 대한 탐색

김수근,양미현,정동혁 圓光大學校 附設 體力科學硏究所 2003 體力科學硏究 Vol.26 No.1

The prescription of resistance training is both a science and an art. Ultimately, individualized training programs provide for optimal changes in the exercise prescription process and result in the best overall training response for the individual. Although guidelines can be given, the art of designing effective resistance training programs requires logical exercise prescription followed by evaluation, testing, and interaction with the trainee. Resistance training prescription is a dynamic process that requires the strength and conditioning professional to respond to the trainee's changing adaptation levels and functional capacities with altered program designs to meet the changing training goals. Resistance training of children has gained acceptance and popularity primarily because strength gains can occur, bone development may be enhanced, and injuries might be prevented in other sports and activities with developmentally appropriate training programs in recently. When designing a program, consider the developmental and physical differences among children, exercise tolerance, and safety issues so that acute and chronic injuries are minimized and the benefits to the participating children are maximized. When prescribed appropriately, resistance training is effective for developing physical fitness, health, wellness and for the prevention and rehabilitation of orthopedic injuries. Because resistance training is an integral component in the comprehensive health promotion program. We have reviewed the positive and negative aspects of children participation in resistance training programs. The benefits to children are reported to be increased strength, endurance, muscle capacity, and flexibility; more energy; and improved self-image and confidence. The negative aspects include some pain or stiffness and other nonspecific problems. The positive and negative aspects of resistance training are therefore very similar to those in adults populations. Scientific investigations have demonstrated that resistance training can be safely and successfully implemented in children. Proper design and progression of a resistance training program for children is vital to optimal benefits from resistance exercise.

여성을 위한 저항트레이닝 처방에 대한 탐색

김수근,양미현,정동혁 圓光大學校 附設 體力科學硏究所 2003 體力科學硏究 Vol.26 No.2

Resistance training, also known as strength or weight training, has become one of the most popular forms of exercise both for enhancing an individual's physical fitness and for conditioning athletes. Individuals who participate in a resistance training program expect the program to produce certain benefits, such as increased strength, increased muscle size, improved sports performance, increased fat-free mass, and decreased body fat. A well-designed and consistently performed resistance training program can produce all these benefits. When prescribed appropriately, resistance training is effective for developing physical fitness, health, wellness and for the prevention and rehabilitation of orthopedic injuries. Because resistance training is an integral component in the comprehensive health promotion program. Although female's absolute strength is less than male's, the difference is greatly reduced if compared on a total body weight or lean body mass basis. This is especially true for the lower body where no strength difference on a lean body mass basis between the genders has been shown. Female's adaptations to a resistance training program are of the same magnitude or even slightly greater than male's for some variables. This means that, in general, resistance training programs for females do not need to be different than those for males, except that the absolute resistance used will be less. Menstrual irregularities may be more prevalent in females performing strenuous resistance activity, as compared to the normal population. However, menstrual irregularities normally cease once strenuous resistance training is stopped. Resistance training can result in many of the fitness characteristics desired by many females of a fit appearance and increased strength and power for daily and sports activities. We have explored the positive and negative aspects of females participation in resistance training programs. The benefits to females are reported to be increased strength, endurance, muscle capacity, and flexibility; more energy; and improved self-image and confidence. The negative aspects include some pain or stiffness and other nonspecific problems. The positive and negative aspects of resistance training are therefore very similar to those in males populations. Scientific investigations have demonstrated that resistance training can be safely and successfully implemented in females populations. Proper design and progression of a resistance training program for females is vital to optimal benefits from resistance exercise. The results of data provided by this research on resistance training for health shows that there is enough existing evidence to conclude that resistance training, particularly when incorporated into a comprehensive fitness program, can offer substantial health benefits which can be obtained by persons of all ages. These benefits, including improvements in functional capacity, translate into an improved quality of life.

악관절 급성 손상시 관절강 세척술의 효과에 관한 연구

이동근,문철,김장현 원광대학교 생체재료·매식연구소 1996 원광생체재료·매식 Vol.4 No.3

This study has demonstrated the efficacy of arthrocentesis of upper temporomadibular joint (TMJ) compartment in cases of severe pain and limited maximum mouth opening (MMO) in traumatic hemarthrosis of TMJ. Thirteen patients complaining of severe pain and limited MMO were treated by irrigation of the upper compartment of the affected TMJ with lactated Ringers solution. This treatment was found to be effective in reestablishing normal mouth opening and relieving pain within I week in postoperative. It is suggested that arthrocentesis simple, less invasive, inexpensive, and highly efficient procedure, which can be performed under local anesthesia, is used in traumatic hemarthrosis cases with severe pain and limited MMO.

2상 스테인리스강의 인장특성에 미치는 오스테나이트상의 함량 및 합금원소의 영향

주동원,성장현,이성근 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1

The effect of alloying elements addition, austenite content and distributions on the tensile properties and corrosion resistance of duplex and super duplex stainless steels has been investigated by changing heat treatment conditions. With the addition of N and Cu, the austenite content of duplex stainless steels increased. After heat treating the super duplex stainless steel, the austenite content increased above 1200℃ and the ferrite single phase temperature shifted to 50℃ high in comparison to duplex stainless steel. Due to the stored energy induced from cold rolling the super duplex stainless steel. the specimen with fibous structure showed to be increased in austenite content compared to the specimen with dispersed structure. Tensile strengths decreased and elongations increased with increasing austenite content. The super duplex stainless steel with fibrous structure showed superior tensile strengths and elongations to the fibrous duplex stainless steel and super duplex stainless steel with dispered structure. The effect of Cu and CU+W addition on tensile properties was small. The passive current density and critical current density of high alloyed super duplex stainless steel showed value in comparison to duplex stainless steel. The Cu+W added super duplex stainless steel appeared the highest corrosion resistance among all specimens.

급성 심근 경색에서 시행한 관상 동맥 우회술의 조기 결과

지현근,이원용,김응중,두영철,한규록,오동진,임종윤 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.8

사회체육활동과 청소년의 공격행동, 불안 및 스트레스와의 관계

양재근,서동균,김재현 한국학교체육학회 2000 한국학교 체육학회지 Vol.10 No.1

본 연구는 사회체육활동이 청소년의 공격행동, 불안 및 스트레스에 미치는 영향을 규명하는데 그 목적이 있다. 자료 분석을 위하여 사용한 통계기법은 ANOVA와 다중 범위 테스트이었다. 인지적·감정적 상태 질문지는 정신적 흥분과 스트레스를 측정하는데 사용되었다. 본 연구에서는 이러한 연구방법을 통해 다음과 같은 결론을 도출하였다. 첫째, 불안과 공격성과의 상관관계를 알아본 결과 상태불안과 공격성과는 0.38의 낮은 상관관계가 있으며, 특성불안과 공격성몬 0.65의 비교적 높은 정적인 상관관계가 있었다. 둘째, 사회체육프로그램이 적용되기 전과 적용된 후의 집단은 폭력(0.83), 부정성(2.00), 원한(1.83), 죄책감(2.50)에서 유의수준p<.05에서 통계적으로 의의 있는 차이가 있었다. The purpose of this study was to examine the Effects of Leisure Activities on violent action, anxiety and stress in Juvenile. Subjects of this study were sampled with 273 middle school students. Statistics employed in this study were ANOVA and multiple range test(Scheffe). Cognitive-Emotional State Questioner was used e test Psychological Anxiety and stress. Results were as follows. First, The relationship between conditional anxiety with trait eagerness was 0.38 and trait anxiety with violent action was 0.65. Second, The group which participated in physical activity showed meaningfully decreased rate of violent action(3.83), negative thought(2.00), hatred(1.83), sense of guilty(2.50) in p<.05. The two conclusion above shows, the sports participation affect juvenile's psychological state in positive way which increase positive lector for psychological well-being.

鎔接殘留應力이 應力比에 따라 疲勞龜裂傳播에 미치는 影響

表東根,李龍福,金鍾鉉,吳湞淵 弘益大學校 1989 弘大論叢 Vol.21 No.2

To examine the effects of the welding residual stress on Mode I fatigue crack propagation behavior, 3mm thickness SS41 steel plate was welded by an Auto-matic Submerged Arc Welding. Initial residual stress and relaxation residual stresses according to each stress ratio were measured. The fatigue crack propagation behavior from the region of compressive residual stress to region of tensile residual stress was analyzed. The results predicted by the Forman's equation using the superposition approach of the respective stress intensity factors for the initial residual stress and for the applied stress according to each stress ratio were compared with experimental data. The validity of the superposition approach was investigated. The conclusion are summerized as follows: 1. When the component is subjected to a constant amplitude cyclic tensile loading, the welding residual stress is reduced as stress ratio increase. 2. As the fatigue crack is propagation through the compressive residual stress field, it was found that the effects of welding compressive residual stress on fatigue crack growth in weldments, and the stress ratio decreases, become larger and delay the fatigue crack growth rate. 3. For negative values of the effective stress ratio, R? in the welding compressive residual stress field, the prediction of fatigue crack growth rate by the Forman's equation were found to be corresponded to experimental data for stress ratio R?0.3, as the effective stress ratio R? approached zero, when the stress ratio R>0.3 the prediction of the fatigue crack growth rate by Forman's equation were found to be impossible.