케미칼 크랙킹 방법을 이용한 플라스틱 제품의 응력측정에 관한 연구

원시태 ( S. T. Won ),김태범 ( T. B. Kim ),이실 ( S. Lee ),원정민 ( J. M. Won ),차규호 ( K. H. Cha ),류민영 ( M. Y. Lyu ) 한국고무학회 2012 엘라스토머 및 콤포지트 Vol.47 No.4

사출성형품에서 잔류응력은 성형공정 중 열과 전단응력에 의해 형성된다. 잔류응력을 평가하는 방법은 여러 가지가 있는데, 불투명한 제품에서의 잔류응력은 케미칼 크랙킹 테스트 방법으로 측정 할 수 있다. 이 방법은 시편과 솔벤트가 반응하게 하여 측정하는 방법이다. 크랙은 응력의 크기에 따라 형성되기 때문에 크랙의 크기나 수를 측정하여 응력을 정량적으로 측정한다. 본 연구에서는 케미칼 크랙킹 방법으로 잔류응력을 측정하기 위한 기초자료인 응력과 크랙과의 관계를 규명하기 위한 실험을 수행하였다. 시편을 제작하기 위한 재료는 PC/PBT와 PC/ABS사용하였으며 지그를 이용하여 시편을 변형을 주고 이를 솔벤트에 담궈서 크랙을 유도하였다. 솔벤트는 tetrahydrofuran과 methyl alchol을 이용하여 제조하였다. 두 재료 모두 응력이 어느 정도 이상에서만 크랙이 형성되었으며, 크랙은 응력이 증가함에 따라 대략 2차함수로 증가하였다. Residual stress in the injection molded part is originated from thermal shrinkage and shear stress during injection molding process. There are many measurement methods of residual stress in the plastic part. Residual stress in opaque products can be measured by chemical cracking test. This method enables the solvent and specimen to react and to cause cracks. Cracks developed according to the level of residual stress. Thus the stresses in plastic part can be quantitatively measured by counting the number of cracks or measuring the size of cracks. Relationship between stress and number of cracks in a plastic specimen has been investigated in this study. Bergen jig was used to give a strain in the specimens those were molded using PC/PBT and PC/ABS. Solvent for the chemical cracking test was prepared using tetrahydrofuran and methyl alcol with the ratio of 1 to 3. Stresses in the specimen can be calculated by strains those were imposed by Bergen jig. Cracks were developed for stress higher than certain level. The number of cracks increased by second order function for stress.

삼킴 장애가 있는 뇌졸중 노인 환자에서 저항성 고개 숙이기 운동과 Shaker 운동의 목뿔위 및 목빗근 활성 비교

김본이(Bon Yi Kim),이 슬(Seul Lee),문종훈(Jong Hoon Moon),원영식(Young Sik Won) 한국장애인재활협회 2016 재활복지 Vol.20 No.3

저항성 고개 숙이기 운동과 shaker 운동은 목뿔위근의 강화를 사용되는 중재법이다. 이전의 연구들에서는 삼킴 장애가 있는 환자들 대상으로 두 운동을 비교하지 않았다. 본 연구는 삼킴장애를 가진 뇌졸중 노인 환자에게 저항성 고개 숙이기 운동과 shaker 운동이 목뿔위근, 목빗근에 미치는 효과를 알아보고자 하였다. 10명의 삼킴 장애가 있는 뇌졸중 노인 환자가 자발적으로 연구에 참가하였다. 모든 대상자들은 저항성 고개 숙이기 운동(등척성, 등속성), shaker 운동(등척성, 등속성)을 순서대로 수행하였으며, 10회 반복하였다. 저항성 고개 숙이기를 수행한 후, 대상자들은 근피로를 최소화하기 위하여 5분간 휴식을 하였다. 두 운동 동안 목뿔위근과 목빗근의 활성을 표면 근전도를 이용하여 분석하였다. 윌콕슨 부호 순위 검정은 그룹 내 저항성 고개 숙이기와 shaker 운동에서 근활성에 대한 차이를 평가하기 위하여 사용하였다. 저항성 고개 숙이기 운동과 shaker 운동은 목뿔위근에서 유의한 차이를 보이지 않았다(p>.05). 저항성 고개 숙이기 운동은 shaker 운동보다 목빗근에서 유의하게 낮은 활성을 보였다(p<.05). 삼킴 장애가 있는 뇌졸중 노인 환자에게 저항성 고개 숙이기 운동이 shaker 운동보다 삼킴 기능 향상을 위한 더 효과적인 치료 방법으로 사용될 수 있을 것이다. Chin Tuck Against Resistance Exercise(CTARE) and Shaker exercise is used to common for strengthening of suprahyoid muscle. No previous studies was compare of two exercises for patients with dyaphagia. This study investigated the effects of CTARE and Shaker exercise on suprahyoid, sternocleidomastoid muscle activity in stroke older patients with dysphagia. Ten stroke patients with dyaphagia voluntarily participated in this study. All subjects was performed in the order in the CTARE (isometric, isokinetic), Shaker (isometric, isokinetic), and repeated each ten trials. After CTARE was performed, subjects took a 5 min wash out period to minimize muscle fatigue. Activity of suprahyoid and sternocleidomastoid muscle during two training was analyzed using surface electromyography(sEMG). Wilcoxon signed rank test was used to assess differecences for muscles activity between the effects of the CTAR and Shaker exercise within group. CTARE and Shaker exercise showed no significant difference activity in suprahyoid muscle(p > .05). CTARE showed significantly lower muscle activity in sternocleidomastoid muscle than Shaker exercise(p < .05). CTARE in stroke older patients with dysphagia may be a effective intervention to improve swallowing function than Shaker exercise.

인공신경망을 이용한 알코올 의존 선별 검사의 유용성

이 재 원(Jae-Won Lee),최지욱(Jee-Wook Choi) 한국중독정신의학회 2005 중독정신의학 Vol.9 No.2

Objectives:Alcohol screening test using direct questionnaire had the risk of high false negative. The aim of this study is the development of a reliable and feasible alcohol dependence screening test using Multiphasic Minnesota Personality Inventory (MMPI) and artificial neural network analysis (NN). Methods:The subjects, 191 inpatients with alcohol dependence and 148 normal controls, were randomly assigned into learning group and testing group. Both neural network and logistic regression formula for screening alcohol dependence were acquired using both the conventional MMPI 13 scales and MMPI 73 scales including additional 60 scales in learning group (56 alcoholics and 44 normal controls). The MMPI scales of remained testing group, 140 alcoholics and 104 normal controls, were tested with two LR formula (13 and 73 MMPI scales) and two learned NN (13 and 73 MMPI scales) whether each subject is alcohol dependence or not. The sensitivity and specificity, and area under the curve of 4 analysis methods, LR or NN using 13 or 73 MMPI scales were calculated and compared. Results:When using conventional MMPI 13 scales, the sensitivity, specificity, and area under the curve (AUC) of LR and NN were 71.1% vs. 57.8-75.6%, 62.5% vs. 48.1-60.6%, 0.668± 0.036 vs. 0.577±0.037-0.716±0.034, respectively. But, in the case of using 73 MMPI scales including 13 conventional scales, the sensitivity, specificity, and area under the curve (AUC) of LR and NN were 79.3% vs. 83.0-93.3%, 67.3% vs. 67.5-81.7%, 0.733±0.034 vs. 0.765±0.033-0.855±0.027, respectively. Conclusion:When using 73 MMPI scales, the sensitivity and specificity of NN were higher than that of NN using 13 scales or LR using 13 or 73 scales. The test using NN using 73MMPI scales is a useful alcohol dependence screening tool. It is suggested that the application of NN in screening another substance use disorder or game addiction might be useful.

국제물품매매 계약에서 전자기록의 유효성에 관한 고찰

이 창 숙(Chang-sook Lee)·강 원 진(Won-jin Kang) 한국국제상학회 2009 國際商學 Vol.24 No.1

In the contract for international sale of goods, electronic records instead of paper documents come to play vital roles for the negotiation and closing of contract between distant parties. It is necessary to review the effectiveness of electronic records. The legal recognition of electronic records is approved under USA Uniform Electronic Transactions Act, Supplement to the Uniform Customs and Practice for Documentary Credits for Electronic Presentation (eUCP) Version 1.1 and Korea Electronic Transactions Act. This paper examined retention and original of electronic records, effect of changes and errors in electronic records occurring in transmissions, the relationship between electronic records and signature, and legal recognition between electronic records and contract. In result, to be effective in the electronic records depends on the information contained in electronic records rather than relies on themselves. Electronic records will be attributed to a party if it is the act of the person, they may not contain an electronic signature. And electronic records can be effective if they comply with the requirements of Time and Place of Sending and Receipt under the Uniform Electronic Transactions Act.

인슐린으로 조절되는 당뇨쥐 상악에서 발치 후 즉시 임플란트 주변에서 골형성

김대원(Dae-Won Kim),허현아(Hyun-A Heo),임상규(Sang-Gyu Lim),이 원(Won Lee),김영실(Young-Sil Kim)표성운Sung-Woon Pyo) 대한구강악안면외과학회 2011 대한구강악안면외과학회지 Vol.37 No.1

Introduction: Dental implants are used routinely with high success rates in generally healthy individuals. By contrast, their use in patients with diabetes mellitus is controversial because altered bone healing around implants has been reported. This study examined the bone healing response around titanium implants placed immediately in rats with controlled and uncontrolled diabetes. Materials and Methods: Twenty rats were divided into the control, insulin-treated and diabetic groups. The rats received streptozotocin (60 mg/kg) to induce diabetes; animals in the insulin-treated group also received three units of subcutaneous slow-release insulin. A titanium implant (1.2×3 mm) was placed in the extraction socket of the maxillary first molar and bone block was harvested at 1, 2 and 4 weeks. Results: Bone formation around the implants was consistently (from 1 to 4 week post-implantation) slower for the diabetic group than the control and insulin-treated group. Bone morphogenesis in the diabetic rats was characterized by fragmented bone tissues and extensive soft tissue intervention. Conclusion: The immediate placement of titanium implants in the maxilla of diabetic rats led to an unwanted bone healing response. These results suggest that immediate implant insertion in patients with poorly controlled diabetes might be contraindicated.

Le Fort I 골절단술을 통한 상악의 후상방 회전에 따른 상순과 비부의 연조직 변화

권영욱(Young-Wook Kwon),표성운(Sung-Woon Pyo),이 원(Won Lee),박재억(Je Uk Park) 대한구강악안면외과학회 2011 대한구강악안면외과학회지 Vol.37 No.6

Introduction: This study evaluate the soft tissue changes to the upper lip and nose after Le Fort I maxillary posterosuperior rotational movement. Materials and Methods: Twenty Skeletal class III patients, who had undergone bimaxillary surgery with a maxillary Le Fort I osteotomy and bilateral sagittal split ramus osteotomy, were included in the study. The surgical plan for maxilla was posterosuperior rotational movement, with the rotation center in the anterior nasal spine (ANS) of maxilla. Soft and hard tissue changes were measured by evaluating the lateral cephalograms obtained prior to surgery and at least 6 months after surgery. For cephalometric analysis, four hard tissue landmarks ANS, posterior nasal spine [PNS], A point, U1 tip), and five soft tissue landmarks (pronasale [Pn], subnasale [Sn], A Point, upper lip [UL], stomion superius [StmS]) were marked. A paired t test, Pearson s correlation analysis and linear regression analysis were used to evaluate the soft and hard tissue changes and assess the correlation. A P value <0.05 was considered significant. Results: The U1 tip moved 2.52±1.54 mm posteriorly in the horizontal plane (P<0.05). Among the soft tissue landmarks, Pn moved 0.97±1.1 mm downward (P<0.05), UL moved 1.98±1.58 mm posteriorly (P<0.05) and 1.18±1.85 mm inferiorly (P<0.05), and StmS moved 1.68±1.48 mm posteriorly (P<0.05) and 1.06±1.29 mm inferiorly (P<0.05). The ratios of horizontal soft tissue movement to the hard tissue were 1:0.47 for the A point and A point, and 1:0.74 for the U1 tip and UL. Vertically, the movement ratio between the A point and A point was 1:0.38, between U1 tip and UL was 1:0.83, and between U1 tip and StmS was 1:0.79. Conclusion: Posterosuperior rotational movement of the maxilla in Le Fort I osteotomy results in posterior and inferior movement of UL. In addition, nasolabial angle was increased. Nasal tip and base of the nose showed a tendency to move downward and showed significant horizontal movement. The soft tissue changes in the upper lip and nasal area are believed to be induced by posterior movement at the UL area.