The objective of this study is to analyze the difference between the theoretically calculated torque values of lead screws used in vehicle seat rails and the required torque values due to various disturbances that occur in actual systems. Lead screws were classified into square and trapezoidal threads and modeled by two lead type. Dynamic analysis models were constructed by applying contact conditions and rotational joints between the lead screw and nut. The validity of the dynamic model was verified by comparing the torque values obtained from rigid body dynamic analysis with the theoretically calculated torque values. Then, the lead screw was modeled as a flexible body to investigate the torque variation required for the lead screw when dynamic loads are considered. This study will help predict the actual torque values of lead screws for seat rails.

Screw jet equipment has been developed based on the existing accumulated experimental indicators in the semiconductor industry, and for specific performance development, it is necessary to visually check a process in which a high viscosity solution is discharged to a nozzle through a screw. Since the transparency of the exterior is not guaranteed after design and production due to the characteristics of the equipment, simulation must be performed to confirm the performance data according to the internal shape. Therefore, in this study, the screw jet equipment was simulated using the moving particle system, and through this, all processes of the screw jet internal solution flow were visually checked and computerized data capable of predicting the performance of the equipment was secured.

현재 조림지에서 포트묘를 식재하는데 동력식혈기나 식재도구가 주로 이용된다. 동력 식혈기의 경우 에는 엔진이 일반적으로 많이 사용되고, 식재도구는 삽이나 포트묘용 식재기, 굴취봉 또는 호미들을 주 로 사용한다. 그러나 이러한 방법들은 경사지고 험준한 산림지형에서 이용하기에는 인건비와 생산성 등 에 문제가 있다. 이와 같은 문제점들을 해결하기 위해 동력의 장점과 도구의 편리성을 감안하여 배터리 와 DC motor 및 스크류를 이용한 새로운 경량 식혈기를 개발할 필요가 있다고 판단된다. 경량 식혈기 는 무게를 5kgf 내외로 가볍게 하기 위해서는 굴취력이 뛰어난 스크류의 개발이 매우 중요하다. 또한 스크류의 굴취력은 DC motor와 배터리의 용량을 결정하는 요인이 된다. 따라서 본 연구에서는 경량화 된 식혈기를 개발하기 위해 포트묘 식재에 적용할 수 있는 소형과 중형 스크류 5종(길이 170㎜, 피치 3.0∼4.0개, 그리고 나선각 15°~20°)에 대해 이론 회전력을 산출하여 모터와 감속기의 용량을 설정하 고, 실제 토양에 적용하여 최대 회전력을 구명하였다.

압출성형조건에 따른 분리대두단백(Isolated soy protein) 압출성형물의 조직화와 물리적 특성의 차이를 알아보고자 팽화율, 수분흡수력, 탄성력, 응집력, 절단강도, 조직잔사지수, 색도 등의 실험을 통해 비교분석하였다. 실험재료는 분 리대두단백을 100% 사용하여 압출성형하였다. 분리대두단백 압출성형물 제조에 사용한 압출성형기는 실험용 쌍축압 출성형기이며, 공정변수는 용융물의 온도와 원료투입량은 140°C와 100 g/min으로 고정시키고 스크루 회전속도는 150, 250, 330 rpm, 수분함량은 40, 50, 55, 60% 로 하였다. 직경팽화율은 큰 차이를 나타내지 않았지만 수분함량이 가장 낮은 40% 일 때 가장 높은 값(2.67±0.18)을 나타내었다. 비길이는 수분함량이 증가하거나 스크루 회전속도가 증가할수 록 값이 증가하는 값을 나타내었다. 체적밀도도 직경팽화율과 같이 큰 차이를 나타내지 않았지만 스크루 회전속도가 낮을수록 체적밀도 값이 증가하는 값을 나타내었다. 분리대두단백의 압출성형물의 수분흡수력은 스크루 회전속도 250 rpm, 수분함량 40%에서 가장 높은 값(482.24±34.5)을 나타냈고, 수분함량이 증가할수록 수분흡수력은 감소하였다. 또 한 수분함량을 55%, 스크루 회전속도가 증가할수록 수분흡수력은 증가하였다. 탄성력과 응집력은 서로 비례한 값을 나타냈는데, 스크루 회전속도가 감소할수록 높은 값을 나타냈다. 또한 스크루 회전속도가 감소할수록 절단강도의 값 도 증가하는 값을 나타냈다. 조직잔사지수는 공정변수에 따라 큰 차이를 나타냈는데, 55% 수분함량에서 150 rpm 일 때 가장 큰 값인 30.92±14.90, 40% 수분함량에서 250 rpm 일 때 가장 작은 값인 0.52±0.24를 나타내었다.

This study was conducted to develop a handy earth auger for use in sloppy and rugged forest terrains in order to reduce labor cost which comprises a major part of the production costs in forest afforestation projects. The first prototype is developed consist of two parts, the soil-digging screw and the battery power source. The specifications of the first prototype screw are: length of 170㎜, a top diameter of 60㎜, bottom diameter of 47㎜, 23° angle for each helix, and a 50㎜ awl-head tip. The use of a single line of screw was selected for reduced weight. In addition, a power source of rotary DC Motor(WD-6G2425, WONILL, Korea) with a maximum torque of 30㎏ f-㎝, rotation of 20-30rpm, K6G30C decelerator with a reduction ratio of 30:1 which could be used with no load for 48 was operated. In consideration of its weight, a lithium battery was utilized in line with the goal of developing a lightweight auger. In order to evaluate the performance of the first prototype, test sites were selected as 6 areas. The rotational force was found to be highest in area A(Solid area), followed by areas F(Mounted slope 40° area) and E(Mounted slope 30° area). It was also observed that in general, the rotational force increased along with the increase in soil depth with the maximum rotational force recorded at 10㎝.

The purpose of this study was to investigate the initial bone tissue change and ,to repair on the Miniscrew and surrounding tissue under the various types orthodontic forces by use of niti closed spring through the polarizing φ>larizing microscopic fmdings. For this study, three young adult mongrel dogs(experimental group 1, 2, 3) were used, and 12 titanum miniscrew(a1, a2, a3, b1, b2, b3, c1, c2, c3, d1, d2, d3) were inserted into the palatal bone. The experimental design was consisted of equal opposite group(B), extrusion group(C), double same sided group(D). and group(A) was controlled. Group B, C, D miniscrews were loaded with 150gm of force immediately after placing to palatal side, and group B miniscrews were loaded with changed force of equal amount to buccal side after 10 없ys. and Group C was loaded extrusive force, group D was loaded double amount to palatal side at same time. The experimental animals in each group and control group were sacrified at one, three, and six weeks following implatation the miniscrew to make the samples for polarizing microscofic findings on palatal bone and miniscrew. All samples were examed and compared the 비stologic changes through the polarizing microscpe. The obtained results were as follows. 1. Under equal 01ψ。site force group, the histologic features of tissues around Miniscrew in experimental B group was no difference between the control group under equal opposite force group 2. Under extrusive force after lateral force group, it's bone density was decreased less than control groupunder extrusive force after lateral force group. πùs group was most p∞r bone densi마 ofall. 3. Under double same side group, inital feature was sirnlar to control group , but after 6weeks bone density was decreased along the Miniscrew surfaceunder double same side group. Based on these experimental results, in the prac디ce ， Miniscrew was usefull as skeletal anchorage in immediately load after implantation on alveolar bone under lateral force and opposite lateral force, but at applied extrusive force and double opposite side force were non- useful as skeletal anchorage with long-term treatrnent.