Nd:YAG 레이저를 이용한 폴리머의 투과접합에서 열 유동 및 열 변형 해석

차상우,김진범,나석주,Cha, Sang-Woo,Kim, Jin-Beom,Na, Suck-Joo 대한용접접합학회 2006 대한용접·접합학회지 Vol.24 No.6

Laser Transmission Joining (LTJ), which is a joining process of polymers by using different transmission rates of materials, was studied numerically. Unlike previous studies, energy loss by reflection at the surface was included. Besides, energy absorbed in the transparent substrate is also considered to increase the accuracy of the analytical results. Furthermore, thermal deformations of the substrates were also calculated. Temperature distribution of the substrates on the joining process could be effectively predicted by using the thermal analysis model developed, which could also analyze the rising phenomenon of the absorbing substrate by bulge effect. Calculated results show that temperature of the absorbing substrate is higher than that of transparent substrate when the laser is being radiated, and this temperature difference causes more thermal deformation in absorbing substrate, which results in the surface rise of the absorbing substrate. Comparison of calculated results with corresponding experimental results could confirm the validity of the numerical analysis model proposed.

2014 소화기암에 대한 대국민 의식조사

차상우,Sang-Woo Cha 대한소화기암연구학회 2015 Journal of digestive cancer reports Vol.3 No.2

Currently, inappropriate information regarding cancer is being disseminated indiscreetly via the media and Internet. Many people are confused due to the mixed presence of facts and misinformation concerning cancer. Owing to the flood of information, especially that concerning gastrointestinal cancer (the most common cancer in Korea), patients with gastrointestinal cancers, their family members, and medical staff, as well as the general public, are faced with a number of problems in understanding, treating, and overcoming this type of cancer. Therefore, investigating the level of recognition for and understanding of gastrointestinal cancers among these populations is very important for the prevention, diagnosis, and management of this disease. This review article investigated the differences in the recognition levels of the general understanding, prevention, quality of life, pain control, and the ethical issues of gastrointestinal cancer treatment among the general public, patients with gastrointestinal cancers, their family members, and medical staff via surveys.

폴리머의 레이저 투과접합 시 접합부의 기계적 성질에 관한 연구

차상우,김진범,윤석환,나석주,Cha, Sang-Woo,Kim, Jin-Beom,Yoon, Suk-Hwan,Na, Suck-Joo 대한용접접합학회 2007 대한용접·접합학회지 Vol.25 No.2

Laser Transmission Joining (LTJ) of plastics is a process in which light of suitable wavelength is transmitted through a transparent substrate that is in contact with an absorbing one. In this paper, LTJ is investigated by preliminary experiments from the viewpoint of mechanical engineering. To understand transmitting characteristics of each polymer substrate, transmission rate, reflection rate and absorption coefficient of polymer are measured by using a laser power-meter. Characteristics of joining in the spot welding and seam welding are investigated by measuring the fracture load. Fracture load increases in accordance to the laser power and irradiation time. However, when the laser power is over 60W and irradiation time over 4seconds, fracture load decreases. This phenomenon is probably due to heat-softening of materials. Besides, cavities are generated at a joint by evaporation of water molecules, which can be suppressed by introduction of a gap between two substrates.

간내 담석의 치료

차상우 ( Sang-woo Cha ) 대한소화기학회 2018 대한소화기학회지 Vol.71 No.5

Intrahepatic duct (IHD) stone is the presence of calculi within the intrahepatic bile duct specifically located proximal to the confluence of the left and right hepatic ducts. This stone is characterized by its intractable nature and frequent recurrence, requiring multiple therapeutic interventions. Without proper treatment, biliary strictures and retained stones can lead to repeated episodes of cholangitis, liver abscesses, secondary biliary cirrhosis, portal hypertension, and death from sepsis or hepatic failure. The ultimate treatment goals for IHD stones are complete removal of the stone, the correction of the associated strictures, and the prevention of recurrent cholangitis. A surgical resection can satisfy the goal of treatment for hepatolithiasis, i.e., complete removal of the IHD stones, stricture, and the risk of cholangiocarcinogenesis. On the other hand, in some cases, such as bilateral IHD stones, surgery alone cannot achieve these goals. Therefore, the optimal treatments require a multidisciplinary approach, including endoscopic and radiologic interventional procedures before and/or after surgery. Percutaneous transhepatic cholangioscopic lithotomy (PTCS-L) is particularly suited for patients at poor surgical risk or who refuse surgery and those with previous biliary surgery or stones distributed in multiple segments. PTCS-L is relatively safe and effective for the treatment of IHD stones, and complete stone clearance is mandatory to reduce the sequelae of IHD stones. An IHD stricture is the main factor contributing to incomplete clearance and stone recurrence. Long-term follow-up is required because of the overall high recurrence rate of IHD stones and the association with cholangiocarcinoma. (Korean J Gastroenterol 2018;71:247-252)

고령자 담석증의 임상적 고찰

차상우(Sang Woo Cha),천갑진(Gab Jin Chun),박용순(Yong Soon Park),송동화(Dong Hwa Song),조영덕(Young Deok Cho),김진오(Jin Oh Kim),봉형근(Hyung Keun Bong),조주영(Joo Young Cho),김연수(Yun Soo Kim),이준성(Joon Seong Lee),이문성(Moon Sun 대한소화기학회 1996 대한소화기학회지 Vol.28 No.2

N/A Background/Aims: Gallstone is uncommon before adolescence, and its incidence increases v:ith age. In elderly patients, one of the important characteristics of the ga]lstone disease is that they often have bile duct stones causing acute obstructive cholangitis. Another is that they could be accompained by other diseases. Methods: We analyzed 2,154 patients surgical]y or radiologically proven gallstone patients at the Soon Chun Hyang University Hospita] from l984 to 1994 and compared the clinical characteristics of elderly patients group(over 60 years) with younger patients group(under 60 years). Results: The peak incidence of gallstone (fisease wos noted in the 6th decade and the mean age was 55 years. Elderly patients group were 40.6%(874 cases) and younger patients group were 59.4%(l,280 cases'). Male to female ratio of eler]y patients vras I:1.IO. The location of stones was gallbladder(GB) in l,395 cases(64.9%), multiple sites in 416 cases(19.3%), common bile duct(CBD) in 214 cases(9.9%) and intrahepatic duct(IHD) in 129 cases(5.9%). In elderly patients group, the ]ocation of stones was multiple sites in l86 cases(2l.3%)and CBD in 120 cases(l3.7%). Frequency of stones in multiple sites and GB was significontly higher in elderly patients group than younger patients group(pO.OJ). The prominent clinical manifestations were right upper quadrant abdominal pain(24.5%), epigastric pain(19.4%), and no symptoms(l0.8%). In elderly patients group, chilling and jaundice were significantly higher than younger patients group(p 0.01). The associated diseases were cardiac diseases(l3.7%), diabetes me]litus(8.1%), malignancy (7.3%), liver cirrhosis(6.4%), and hepatitis(5.2%). Cardiac diseases, respiratory diseases, diabetes rnellitus and malignancy were more frequently associated in elder]y patients group than in younger group(p0.01). The incidence of complication was 10.7%(230/2,154)and mortality rate was 1.1% (24/2,154). In elderly patients group, the incidence of complication* and mortality* was signifi- cantly higher than younger patients group(*: p0.01; **: p0.05). Conclusions: The incidence of stones in CBD and mutiple sites, complication and morta]ity rate were higher, and chilling and jaundice were more frequently noted in elderly patients group than younger patients group. Our results suggest that ear]y diagnosis and proper treatment migbt be necessary in elderly patients with the gallstone disease. (Korean J Gastroenterol 1996; 28:260-266)

편마비 장애인을 위한 수작업 보조도구 연구

차상우(Cha Sang-Woo),고영준(Ko Young-Jun) 한국디자인학회 2005 한국디자인학회 학술발표대회 논문집 Vol.2005 No.5

아칼라지아 환자에서 보툴리늄 독소주입 치료 후 미만성 식도경련 , 호두까기 식도로의 이행에 관여하는 인자에 대한 연구

차상우(Sang Woo Cha),이준성(Joon Seong Lee),임희혁(Hee Hyuk Im),황경란(Kyung Ran Hwang),정인섭(In Sup Jung),천갑진(Gab Jin Cheon),김진오(Jin Oh Kim),조주영(Joo Young Cho),이문성(Moon Sung Lee),심찬섭(Chan Sup Shim),김부성(Boo Sung Ki 대한소화기기능성질환·운동학회 2001 Journal of Neurogastroenterology and Motility (JNM Vol.7 No.2

N/A Backgroud/Aims: To evaluate the factors which are related to the transition from achalasia to diffuse esophageal spasm (DES) or nutcracker esophagus (NE) after botulinum toxin inj ection to lower esophageal sphincter (LES). Methods: This study included the 23 patients with achalasia who received an intrasphincteric injection of botulinum toxin. Stational esophageal manometry, 24-hour ambulatory esophageal manometry with Ph monitoring, barium esophagogram and endoscopic ultrasonography were performed before and after treatment. We analyzed the parameters from these studies between the cases that transformed to DES or NE within a week and the cases that do not transit. Result: Five patients (21.7%) transformed to DES (1) or NE (4) within a week. There were significant differences in contraction amplitude of esophageal body (median, 31mmHg vs 23 mmHg, p<0.05) and maximal diameter of esophageal body (median, 2.6 cm vs 4.4 cm, p<0.05) between these five patients and the remaining patients. There were no significant differences in sex, LES pressure and thickness of muscle layer between two groups. Conclusion: Factors involved in transition to NE or DES after botulinum toxin injection to LES of achalasia appears as high amplitude contractions in body of esophagus and less dilation of esophageal body. (Korean Journal of Gastrointestinal Motility 2001;7:188-196)

육미지황탕박의 사료가치에 관한 연구

차상우(Sang-Woo Cha),최현수(Hyun-Soo Choi),김이수(E-Soo Kim),정강석(Kang-Seok Jung),장원섭(Won-Seop Jang),신용준(Yong-Joon Shin),이수기(Soo-Kee Lee) 충남대학교 농업과학연구소 2009 농업과학연구 Vol.36 No.1

본 시험은 육미지황탕박의 사료가치를 측정하기 위한 기초 자료를 제공하기 위하여 두가지 실험을 실시하었다. 실험 1에서는 육미지황탕 단미재료의 열탕 추출 전후의 화학적 조성을 조사하고, 소실률을 알아보기 위하여 육미지황탕박으로 TMR의 0, 10 및 20%를 대체하여 in vitro 실험을 수행하였다. 실험 2에서는 당밀의 첨가가 육미지황탕박 사일리지의 기호성과 반추위내 발효성상을 조사하기 위하여 육미지황탕박에 당밀 첨가수준을 0, 0.5 및 1.0%로 하여 사일리지를 제조하고, 우리나라 재래산양에 대한 기호성과 반추위내 발효성상을 조사하였다. 실험 1의 결과로서, 단백질의 조성에 있어 택사는 열탕침출 후 12.5%로서 높은 편이며 복령은 0.7%로서 매우 적은 편이었다. 조지방은 산수유의 경우 추출 전 후가 각각 7.6 및 8.9%로 높은 편이지만, 나머지 재료는 1.4~4.3%의 범위였다. NDF 함량은 추출 후 기준으로 목단피, 복령, 택사 순으로 높고 숙지황이 가장 낮았다. 그리고 추출 후의 ADF 함량은 산수유, 복령, 목단피의순으로 많고 산약이 가장 낮았다. 육미지황탕박의 TMR에 대한 대체 비율에 따른 건물 소실률은 육미지황탕박의 첨가비율이 높은 시험구에서 많이 감소하였는데 10% 대체 시에는 유의차가 인정되지 않는 범위 내에서 감소하였지만 20% 대체 시에는 0 및 10% 대체 시에 비하여 유의하게 감소하였다. 실험 2의 결과에 있어, 30분 동안 및 6시간동안의 섭취량은 당밀 첨가구가 무첨가구에 비하여 섭취량이 유의하게 많았으며, 당밀 첨가수준이 높아짐에 따라 pH 및 초산의 수준에는 일정한 경향을 관찰할 수 없었고, 총산?프로피온산?발레린산의 수준은 높아지는 경향이었다. 그리고 이소-낙산?낙산?이소-발레린산의 농도는 낮아지는 경향이었다. A/P 비율은 당밀 1% 첨가구에서 가장 낮게 나타났으나 일정한 경향을 나타내지는 않았다. 이상의 결과에서 보면, 육미지황탕박은 TMR 사료 등에서 낮은 범위내에서 활용이 가능한 것으로 판단된다. 육미지황탕박은 열탕처리를 거침으로 인하여 수용성 탄수화물이 부족하므로, 당밀 등의 수용성탄수화물을 첨가하여 사일리지를 제조하는 것은 기호성을 향상시키고, 반추위내 발효성상에도 부정적인 영향이 없어 유용한 방법이라고 생각된다. 첨가 수준에 있어서는 1.0% 수준이면 좋은 품질을 유지할 수 있을 것으로 생각된다. Two experiments were conducted to investigate feed value of Yukmijihwangtang (herbal medicine) meal. In experiment 1, the chemical composition of Yukmijihwangtang ingredients was determined before and after extraction, and investigated the effects of partial substitution of dried Yukmijihwangtang meal on TMR for fattening cattle. In experiment 2, nine Korean native male goats were employed to investigate the palatability and ruminal parameters of Yukmijihwangtang meal silages. In experiment 1, the crude protein content after water extraction was higher in Alisma orientale Juzepczuk (Teaksa), and lower in Pachyma hoelen Rumph (Bokryeong). the crude fat content after water extraction was higher in Cornus officinalis Sieb. et Zucc (Sansuyu), and lower in other ingredients. ADF content after water extraction of Cornus officinalis Sieb. et Zucc (Sansuyu) was higher compared to those of Pachyma hoelen Rumph (Bokryeong) and Paeonia suffruticosa Andrews (Mokdanpi). Dioscorea japonica Thunberg (Sanyak) was the lowest in ADF content. Dry matter disappearance was increased by adding Yukmijihwangtang meal to TMR. In experiment 2, feed intakes of Yukmijihwangtang silage containing molasses (0.5 and 1%) for 30 min and 6 hr were significantly higher than that of control (0%) in Korean native goats. In various ruminl parameters, molasses addition to silage materials trended to increase total VFA, propionate and valerate contents, but trended to decrease iso-butylate, butylate and iso-valerate contents in Korean native goats. In conclusion, Yukmijihwangtang meal could be used as partial substitution of low level in TMR for fattening cattle. Molasses supplementation to silage materials contained with herbal medicine meal could improve its nutritional quality and palatability for Korean native goats. One percent level of molasses addition could give a useful effect in ensiling.

최신 연구 소개 : 직장 Indomethacin 투여가 내시경역행담췌관조영술 후 췌장염 발생을 줄일 수 있는가?

차상우 ( Sang Woo Cha ) 대한소화기학회 2012 대한소화기학회지 Vol.60 No.4

종설 : 재발성 특발성 췌장염의 진단 접근

차상우 ( Sang Woo Cha ) 대한내과학회 2015 대한내과학회지 Vol.88 No.4

Acute recurrent pancreatitis (ARP) most commonly results from alcohol abuse or gallstone disease. Nevertheless, the initial evaluation fails to detect the cause of ARP in 20% to 30% of patients, who are thus diagnosed with idiopathic pancreatitis. Further evaluation is indicated in patients with a severe initial attack of acute pancreatitis or those with two or more attacks. This evaluation might include one or more of the following procedures: specialized laboratory studies, endoscopic ultrasonography (EUS), magnetic resonance cholangiopancreatography (MRCP), or endoscopic retrograde cholangiopancreatography (ERCP). Based on our experience, the initial step in this evaluation should be MRCP or EUS because of the high safety and diagnostic yield of these techniques. If MRCP or EUS is negative, then ERCP with sphincter of Oddi manometry, intraductal ultrasonography (IDUS), or bile analysis should be considered.