Investigations on the effect of guide vane thickness and solidity on shock and unsteady flow characteristic of VNT

Dengfeng Yang,Li’ang Cao,Ce Yang,Dazhong Lao,Harold Sun 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

In this work, the influence of thickness and solidity of guide vane on the unsteady flow of a radial inflow turbine with variable nozzle has been numerically studied. Three vanes with the thickness changes from 0.3 to 0.1 and the solidity changes from 1.43 to 2.86, were chosen for this study. By investigating the unsteady flow field, it is found that the vane with low thickness and high solidity (vane B) can reduce shock by 75 % compared to the vane with high thickness and low solidity (base model); meanwhile, it can also mitigate the nozzle endwall leakage flow thus improves the flow uniformity of rotor inlet. As the intensity of shock and nozzle leakage flow were mitigated, the aerodynamic loading fluctuation of rotor blade can be weakened effectively, which will lead to improved rotor blades forced response. However, at small opening, vane B shows about 0.5 % lower efficiency than the base model; at large open condition, the efficiency degradation of vane B is up to 1.4 %. Therefore, there is a trade-off between the efficiency and forced response when choosing the nozzle vane solidity and thickness.

Experimental and numerical investigation on a novel gas turbocharging system for diesel engine power recovery at high altitude

Dengfeng Yang,Li’ang Cao,Yang Liu,Zhilian Zhang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

Based on the analysis of the plateau performance for a 6 cylinder 8.6 L turbocharged diesel engine, a novel gas turbocharging system (GTS) is proposed to recover the engine power at high altitudes. Besides, a rolling-reflux combustor is designed to meet the structural requirements of GTS as well as to reduce the flow loss. Both the structure of the rolling-reflux combustor and the cycle thermal calculation of the GTS were described in detail in present work. The performance changes and the fuel consumption rate with engine speed at different altitudes of the GTS are compared to the original engine. Results show that when the altitude changes from 3 km to 5 km, the torque and power of the diesel engine with GTS can be recovered to that at sea level. Then, the particle image velocimetry (PIV) test is performed to study the cold flow field at the cylinder head of the rolling-reflux combustor, and the flow conditions are analyzed in detail. Finally, the flow bench is built and the aerodynamic experiment is carried out to verify the effectiveness of GTS.

Ligation of Aberrant Left Hepatic Artery Originating from the Left Gastric Artery in Laparoscopic Gastrectomy for Gastric Cancer. Is it safe?

Ang RR,Lee HJ,Bae JS,Zhu CC,Berlth F,Park SH,Suh YS,Kong SH,Kim SH,Yang HK 대한외과학회 2017 대한외과학회 학술대회 초록집 Vol.2017 No.11

A long-term tunnel settlement prediction model based on BO-GPBE with SHM data

Yang Ding,Yu-Jun Wei,Pei-Sen Xi,Peng-Peng Ang,Zhen Han 국제구조공학회 2024 Smart Structures and Systems, An International Jou Vol.33 No.1

The new metro crossing the existing metro will cause the settlement or floating of the existing structures, which will have safety problems for the operation of the existing metro and the construction of the new metro. Therefore, it is necessary to monitor and predict the settlement of the existing metro caused by the construction of the new metro in real time. Considering the complexity and uncertainty of metro settlement, a Gaussian Prior Bayesian Emulator (GPBE) probability prediction model based on Bayesian optimization (BO) is proposed, that is, BO-GPBE. Firstly, the settlement monitoring data are analyzed to get the influence of the new metro on the settlement of the existing metro. Then, five different acquisition functions, that is, expected improvement (EI), expected improvement per second (EIPS), expected improvement per second plus (EIPSP), lower confidence bound (LCB), probability of improvement (PI) are selected to construct BO model, and then BO-GPBE model is established. Finally, three years settlement monitoring data were collected by structural health monitoring (SHM) system installed on Nanjing Metro Line 10 are employed to demonstrate the effectiveness of BO-GPBE for forecasting the settlement.

Inside a Beehive: The Multiple Merging Processes in the Galaxy Cluster Abell 2142

Liu, Ang,Yu, Heng,Diaferio, Antonaldo,Tozzi, Paolo,Hwang, Ho Seong,Umetsu, Keiichi,Okabe, Nobuhiro,Yang, Li-Lan American Astronomical Society 2018 The Astrophysical journal Vol.863 No.1

내반 변형의 슬관절 전치환술시 내측 상과 절골술의 단기 추시 결과

심재앙 ( Jae Ang Sim ),곽지훈 ( Ji Hoon Kwak ),양상훈 ( Sang Hoon Yang ),김준엽 ( Joon Yub Kim ),이범구 ( Beom Koo Lee ) 대한슬관절학회 2009 대한슬관절학회지 Vol.21 No.3

목적: 내반슬의 슬관절 전치환술에 있어서 내측 측부 인대 이완술시 내측 상과 절골술의 결과에 대해 알아보고자 하였다. 대상 및 방법: 2004년 12월부터 2007년 12월까지 시행한 내측 상과 절골술 32예를 분석하였으며, 평균 나이는 71.0세, 추시 기간은 23.5개월이었다. 임상적 평가는 슬관절 점수, 기능 점수 및 관절 운동 범위를 평가하였고, 방사선학적 평가는 전후방 사진으로 유합 상태를, 긴장 방사선 사진으로 불안정성을, 하지 전장 방사선 사진으로 대퇴-경골 각, 기계적 축 각, 정렬을 평가하였다. 결과: 슬관절 점수, 기능 점수는 각각 수술 전 46.5±7.6점, 39.5±9.2점에서 최종 추시 시 89.1±5.9점, 84.2±8.5점으로 호전되었으며(p<0.001), 관절 운동 범위는 수술 전 101.5±28.2°에서 최종 추시 시 116.0±10.8°로 증가하였다(p=0.006). 유합 상태는 골성 유합이 22예, 섬유성 유합이 10예였다. 대퇴-경골 각은 수술 전 내반 8.2±5.0°에서 최종 추시 시 외반 5.6±1.5°로 교정되었고(p<0.001), 기계적 축 각은 수술 전 내반 13.9±4.5˚에서 최종 추시 시 내반 0.7±1.6°로 교정되었다(p<0.001). 정렬은 중립 정렬 27예, 내반 정렬 4예, 외반 정렬 1예였다. 반대편과 비교한 외반 긴장 방사선 사진상 최종 추시 시 1.0±0.6°의 차이를 보였고, 골성 유합된 군과 섬유성 유합된 군 간의 유의한 차이는 없었다(p=0.175). 결론: 내반슬의 슬관절 전치환술시 내측 상과 절골술은 내측 안정성을 줄 수 있는 유용한 연부 조직균형 술식으로 사료된다. Purpose: We wanted to evaluate the results of medial epicondylar osteotomy for the varus knee when performing total knee arthroplasty. Materials and Methods: We reviewed 32 cases of medial epicondylar osteotomy for treating varus deformity, and these cases underwent operation from December 2004 to December 2007. The average age of the patients was 71.0-years-old and the average follow-up period was 23.5 months. The clinical outcomes were measured, including the Knee Society score (KSS), the function score (FS) and the range of the motion (ROM). The radiological outcomes were measured by anteroposterior simple radiographs for assessing the union state of the osteotomy site, and the valgus stress radiographs and the whole extremity radiographs were used for assessing the femorotibial angle, the mechanical axis angle and the alignment. Results: The KSS improved from 46.5±7.6 to 89.1±5.9 points (p<0.001) and the FS increased from 39.5±9.2 to 84.2±8.5 points (p<0.001). The range of motion increased from 101.5±28.2° to 116.0±10.8° (p=0.006). Bony union occurred in 22 knees and fibrous union occurred in 10 knees. The femorotibial angle was corrected from varus 8.2±5.0° to valgus 5.6±1.5° (p<0.001) and the mechanical axis angle was revised from varus 13.9±4.5° to varus 0.7±1.6°(p<0.001). There were 27 neutral, 4 varus and 1 valgus alignment. On the valgus stress radiographs, the difference compared with the opposite side was 1.0±0.6° and there was no significant difference between the bony union group and the fibrous union group (p=0.175). Conclusion: Medial epicondylar osteotomy for the varus knee when performing total knee arthroplasty could be a useful ligament balancing technique for achieving medial stability of the knee.

슬관절 전치환술에서 발생된 내측 측부 인대 완전 분리와 역학적 정렬의 임상적 관계

심재앙 ( Jae Ang Sim ),이범구 ( Beom Koo Lee ),곽지훈 ( Ji Hoon Kwak ),양상훈 ( Sang Hoon Yang ) 대한슬관절학회 2007 대한슬관절학회지 Vol.19 No.1

자가 슬건과 Ligament Plate<SUP>®</SUP>를 이용한 이중 다발 전방 십자 인대 재건술의 단기 추시 결과

심재앙(Jae-Ang Sim),양상훈(Sang-Hoon Yang),안병근(Byoung-Keun Ahn),이범구(Beom-Koo Lee) 대한정형외과학회 2009 대한정형외과학회지 Vol.44 No.3

목적: 자가 슬건과 Ligament Plate<SUP>®</SUP>를 이용한 이중 다발 전방 십자 인대 재건술 후 최소 1년 이상 단기 추시 결과를 보고하고자 하였다. 대상 및 방법: 50예를 대상으로 하였으며, 전내측 다발로 반건양건, 후외측 다발로 박건을 이용하였다. 대퇴부 전내측 다발은 Ligament Plate<SUP>®</SUP>에 현수 고정, 후외측 다발은 Mersilene tape<SUP>®</SUP>을 이용 고정, 경골부는 이중 post-tie 고정을 시행하였다. 평균 추시 기간은 16.5개월이었고, 임상적, 방사선학적으로 평가하였다. 결과: Lysholm 점수는 92.4±6.8점, IKDC 점수는 A 등급 35예, B 등급 14예, C 등급이 1예로 호전되었다. Lachman 검사는 음성 40예, 경도 9예, 중등도 1예, pivot shift 검사는 음성 45예, 경도 5예로 호전되었다. KT 관절계 검사는 건측에 비해 1.3±1.6 ㎜, 전방 전위 방사선 사진은 1.3±1.3 ㎜로 호전되었다. 터널 확장 정도는 대퇴부가 전내측 1.7±0.6 ㎜, 후외측 1.6±0.7 ㎜, 경골부가 전내측 1.2±0.4 ㎜, 후외측 1.4±0.5 ㎜였다. 결론: 자가 슬건과 Ligament Plate<SUP>®</SUP>를 이용한 이중 다발 전방 십자 인대 재건술은 충분한 조기 고정력과 outside-in 등의 술기를 통한 해부학적 재건으로 우수한 임상 결과를 얻을 수 있었다. Purpose: We wanted to evaluate the clinical outcomes at a minimum 1-year following anatomic double bundle ACL reconstruction with using autogenous hamstring tendons fixed with Ligament Plate<SUP>®</SUP>. Materials and Methods: We evaluated a total of 50 patients. Semitendinosus tendon was used for the reconstruction of the anteromedial bundle and the gracilis tendon was used for the reconstruction of the posterolateral bundle. For femoral fixation, we used an anteromedial bundle that was suspended in Ligament Plate<SUP>®</SUP> and a posterolateral bundle linked with Mersilene tape<SUP>®</SUP>. For tibial fixation, we used double post-tie. The average follow-up period was 16.5 months. We analyzed the clinical and radiographic results. Results: At the last follow-up, the Lysholm score was 92.4±6.8 points. For the IKDC score, there were 35 cases of grade A, 14 cases of grade Band 1 case of grade C. The Lachman test was negative for 40 cases, it was grade 1 for 9 cases and it was grade 2 for 1 case and the pivot shift test was negative for 45 cases and it was grade 1 for 5 cases. The side-to-side differences with the KT-2000 and the anterior drawer radiogram were 1.3±1.6 ㎜ and 1.3±1.3 ㎜, respectively. The femoral tunnel enlarged to 1.7±0.6 ㎜ in the anteromedial aspect and 1.6±0.7 ㎜ in the posterolateral aspect, and the tibial tunnel enlarged to 1.2±0.4 ㎜ in the anteromedial aspect and 1.4±0.5 ㎜ in the posterolateral aspect. Conclusion: Anatomic ACL reconstruction using autogenous hamstring tendons that are fixed with Ligament Plate<SUP>®</SUP> showed good clinical results due to the strong strength of early fixation and the anatomic restoration of the ACL.

Ligation of Aberrant Left Hepatic Artery Originating from the Left Gastric Artery in Laparoscopic Gastrectomy for Gastric Cancer. Is it safe?

Rene Ronson Ang,Hyuk-Joon Lee,Jae Seok Bae,Chun-Chao Zhu,Felix Berlth,Tae Han Kim,Shin-Hoo Park,Yun-Suhk Suh,Seong-Ho Kong,Se Hyung Kim,Han-Kwang Yang 대한종양외과학회 2019 대한임상종양학회 학술대회지 Vol.2019 No.2

대장암의 시대적 변화

이정호,나양원,서병조,장석효,백인욱,이혁상 대한소화기학회 1999 대한소화기학회지 Vol.33 No.1

Background/Aims: This study was conducted to evaluate the chronological changes of colorectal cancer in Korea. Methods: A retrospective analysis of 352 cases with colorectal cancer treated in the period from 1988 to 1996 (recent period) was performed and the results were compared with the previously reported study involving 221 cases with colorectal cancer treated in the period from 1975 to 1987 (past period). Results: The proportion of patients over 60 years in the recent period was 46%, which was significantly higher than that in the past period (30%). Dukes' C patients were 40.6% in the recent period. Although Dukes' D patients were lowered by 6.8%, their proportion wa still 21%. The resection rate was raised by 9.6% to reach 87.8% in the recent period and postoperative morbidity and mortality were decreased. Five-year survival rate was 56.0% in the recen period, it is higher than that of the past period (52%). Five-year survival rate was 100% in Dukes A patients, 83.9% in Dukes' B patients, 53.3% in Dukes' C patients and 8.7% in Dukes' D patient (p=0.000). Conclusions: The incidence of colorectal cancer in the aged group has been increasing. The proportion of Dukes' D patients is decreased. Five-year survival rate of the recent period is higher than that of the past period by 4%. (Kor J Gastroenterol 1999;33:51 - 57)