Prognostic Value of Subcarinal Lymph Node Metastasis in Patients with Esophageal Squamous Cell Carcinoma

Feng, Ji-Feng,Zhao, Qiang,Chen, Qi-Xun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Purpose: The 7th edition of the American Joint Committee on Cancer Staging Manual for esophageal cancer (EC) categorizes N stage according to the number of metastatic lymph nodes (LNs), irrespective of the site. The aim of this study was to determine the prognostic value of subcarinal LN metastasis in patients undergoing esophagectomy for esophageal squamous cell carcinoma (ESCC). Methods: A retrospective analysis of 507 consecutive patients with ESCC was conducted. Potential clinicopathological factors that could influence subcarinal LN metastasis were statistically analyzed. Univariate and multivariate analyses were also performed to evaluate the prognostic parameters for survival. Results: The frequency of subcarinal LN metastasis was 22.9% (116/507). Logistic regression analysis showed that tumor length (>3cm vs ${\leq}3cm$; P=0.027), tumor location (lower vs upper/middle; P=0.009), vessel involvement (Yes vs No; P=0.001) and depth of invasion (T3-4a vs T1-2; P=0.012) were associated with 2.085-, 1.810-, 2.535- and 2.201- fold increases, respectively, for risk of subcarinal LN metastasis. Multivariate analyses showed that differentiation (poor vs well/moderate; P=0.001), subcarinal LN metastasis (yes vs no; P=0.033), depth of invasion (T3-4a vs T1-2; P=0.014) and N staging (N1-3 vs N0; P=0.001) were independent prognostic factors. In addition, patients with subcarinal LN metastasis had a significantly lower 5-year cumulative survival rate than those without (26.7% vs 60.9%; P<0.001). Conclusions: Subcarinal LN metastasis is a predictive factor for long-term survival in patients with ESCC.

Multi-objective Global Optimization for Deformation Near a Hole in an Oxide Forming Alloy Foil Subjected to Thermal Cycling

Feng-Xun Li,Zhen-Zhe Li 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.2

The TBC (thermal barrier coating) systems provide protection against high temperature corrosion of the superalloy substrates in the gas turbine engines. However, the lateral growth of TGO (thermally-grown oxide) and the thermal expansion misfit between TGO and BC(bond coat) induce internal stress which can be sufficient to activate plastic deformation or buckling in TGO. In this paper, the analytic and optimization methods were applied for improving durability of the TBC system. First, an analytic method for obtaining the deformation results of TBC system was applied. In the following step, the analysis results were obtained for the experimental points selected by the D-optimal DOE method. Based on these analysis data, the fitting functions for showing the deformation of the TBC system were constructed using the response surface method. Finally, a multi-objective global optimization method was developed for upgrading durability of the TBC system. The developed analytic and optimization methods can be widely used to improve the performance of the TBC system for the gas turbine engines.

Prognostic Value of Preoperative Serum CA 242 in Esophageal Squamous Cell Carcinoma Cases

Feng, Ji-Feng,Huang, Ying,Chen, Qi-Xun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.3

Purpose: Carbohydrate antigen (CA) 242 is inversely related to prognosis in many cancers. However, few data regarding CA 242 in esophageal cancer (EC) are available. The aim of this study was to determine the prognostic value of CA 242 and propose an optimum cut-off point in predicting survival difference in patients with esophageal squamous cell carcinoma (ESCC). Methods: A retrospective analysis was conducted of 192 cases. A receiver operating characteristic (ROC) curve for survival prediction was plotted to verify the optimum cuf-off point. Univariate and multivariate analyses were performed to evaluate prognostic parameters for survival. Results: The positive rate for CA 242 was 7.3% (14/192). The ROC curve for survival prediction gave an optimum cut-off of 2.15 (U/ml). Patients with CA 242 ${\leq}$ 2.15 U/ml had significantly better 5-year survival than patients with CA 242 >2.15 U/ml (45.4% versus 22.6%; P=0.003). Multivariate analysis showed that differentiation (P=0.033), CA 242 (P=0.017), T grade (P=0.004) and N staging (P<0.001) were independent prognostic factors. Conclusions: Preoperative CA 242 is a predictive factor for long-term survival in ESCC, especially in nodal-negative patients. We conclude that 2.15 U/ml may be the optimum cuf-off point for CA 242 in predicting survival in ESCC.

열 및 기계적 반복하중 하의 내열금속 표면 홀 주변 산화막의 변형 및 응력해석

이봉훈(Feng-Xun Li),강기주(Ki-Ju Kang) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4

In a hot section of gas turbine, the turbine blades were protected from high temperature by not only a thermal barrier coating (TBC) but also cooling air fed through internal passages within the blade. The cooling air is then passed through discrete holes in the blade surface, creating a film of cooling air, further protects the surface from the hot mainstream flow. The holes are subjected to stresses due to the lateral growth of the thermally-grown oxide, the thermal expansion misfit between the constituent layers and centrifugal force by high speed revolution, which often results in cracking. In this work, the deformation and cracks occurring near a hole on a heat-resistant alloy subject to thermo-mechanical cycling were investigated. The experiments showed that during thermo-mechanical cycling the cracks occur around the hole depending applied stress level and number of cycles, which could be explained by analytic solution.

열 및 기계적 피로하중에 대한 Fecralloy 표면 홈의 변형저항성 평가

이봉훈(Feng-Xun Li),강기주(Ki-Ju Kang) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Durability of structural components operating at high temperature depends on the resistance of deformation of bond coat. In this work, the thermal-mechanical fatigue tests were performed under various thermal and mechanical loads with Fecralloy specimens with and without yttrium dopant and the deformation of surface grooves was observed. The effects of the level of temperature and load, and groove orientation as well as the effect of the ratio of curvature on the deformation of the grooves were investigated, the results show that groove deformation depends heavily on the load orientation, and that the higher level of temperature and load induces the larger deformation near the grooves. However, the addition of yttrium dopant was found to suppress the deformation near groove.

열 및 기계적 반복하중 하의 내열금속 표면 홀 주변 산화막의 변형 및 응력해석

이봉훈(Feng-Xun Li),강기주(Ki-Ju Kang) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.9

가스터빈엔진 내의 블레이드에서는 표면에 외부의 찬 공기를 흘려주는 작은 냉각 홀들을 가공하고 열 차단 코팅시스템을 코팅하는 방법으로 기지금속을 고온에서 보호한다. 열 차단 코팅은 열 피로 과정에서 산화막의 성장 및 접합층과 산화막의 열팽창계수의 불일치로 산화막내부에 잔류응력이 발생하며 궁극적으로 코팅층의 분리를 유발한다. 본 연구에서는 내열합금 시편 표면에 작은 홀을 가공하여 여러 가지 고온 유지 조건에서 열 및 기계적 피로 시험을 수행하여 홀 주위의 산화막의 변형을 관찰하였다. 실험결과 기계적 피로가 홀 주위의 산화막의 변형에 중요한 영향을 미치며, 동일한 산화막 두께에서 고온 유지 시간이 짧을수록 변형이 쉽게 발생 하였다. 또한 본 연구에서는 홀 주위 산화막의 응력해석을 위한 이론적인 연구도 시도되었다. In the hot section of a gas turbine, the turbine blades were protected from high temperature by providing a thermal barrier coating (TBC) as well as by cooling air flowing through internal passages within the blades. The cooling air then passed through discrete holes on the blade surface, creating a film of cooling air that further protects the surface from the hot mainstream flow. The holes are subjected to stresses resulting from the lateral growth of thermally grown oxide, the thermal expansion misfit between the constituent layers, and the centrifugal force due to high-speed revolution; these stresses often result in cracking. In this study, the deformation and cracks occurring near a hole on a heat-resistant alloy subjected to thermo-mechanical cycling were investigated. The experiment showed that cracks formed around the hole depending on the applied stress level and the number of cycles. These results could be explained by our analytic solution.

열 및 기계적 반복하중 하에 이중 실린더 모델에서의 응력 및 변형해석

이봉훈(Feng-Xun Li),강기주(Ki-Ju Kang) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

In a hot section of gas turbine, the cooling holes subjected to stresses due to (ⅰ) the lateral growth of the thermally-grown oxide, (ⅱ) the thermal expansion misfit between the constituent layers and (ⅲ) centrifugal force by high speed revolution, which often results in cracking. In this work, the deformation and cracks occurring near a hole on a heat-resistant alloy subject to thermo-mechanical cycling were investigated. A cylindrical model was used for a fundamental understanding of the stress distribution near the hole. The applicability of this model is addressed through comparison with experimental result.

열 및 열-기계적 피로에 의한 내열합금 표면의 홈의 형상변화

이봉훈(Feng-Xun Li),선신규(Shin-Kyu Sun),강기주(Ki-Ju Kang) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

The existence of grooves on the surface of bond coat has significant effect on the instability of thermal barrier system. In this work, the thermal-mechanical fatigue experiments were performed under various thermal and mechanical loads for FeCralloy specimens with and without yttrium dopant to observe the deformation of surface grooves. The effect of temperature, fatigue load and the ratio of curvature on the deformation of grooves were investigated. As the results, it has been found that the higher load level and the higher curvature ratio induces the larger deformation near the grooves. However, the addition of yittrium dopant induces the adverse results.

Mixing of initially stratified miscible fluids in an eccentric stirred tank: Detached eddy simulation and volume of fluid study

Feng Ling Yang,Shenjie Zhou,Cui Xun Zhang,Gui Chao Wang 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.10

Mixing of two stratified miscible fluids in an eccentric stirred tank agitated by a four pitched-blade turbine was studied by using the detached eddy simulation (DES) model and volume of fluid (VOF) method. The fluids were operated in the transitional and mildly turbulent flow regimes. Interfaces between the two miscible fluids during the mixing processes were captured and mixing times were computed. Effects of the Richardson number and eccentricity on the mixing times were quantificationally analyzed. Results show that the spatial and temporal variations of volume fractions of the fluids can be well captured by the method presented in this study. Mixing time increases with the increase of Richardson number. Effect of eccentricity on mixing time depends on Richardson number and the eccentric agitation scheme is not advisable to use to blend the low-viscosity miscible fluids starting from a stratified state, especially for lower Richardson values.

High-Strength Model Material Production for Structural Plane Replica and Its Shear Testing

Feng Ji,Changjiang Liu,Yu Zhang,Luobing Zheng,Kai Pan,Xun Tan 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.1

Shear strength parameters (c, φ) of a structural plane are the key factors for the stability assessment of rock masses. The shear strength parameters are obtained by a structure plane shear test carried out in laboratory. However, it is difficult to obtain test samples with the same surface morphology and to remove the effect of surface irregularity from test results. Based on the similarity principle and orthogonal test, this paper presents a new model preparation method for structural planes using a high-strength mold mixture material. Firstly, the original morphology of the structural plane is recorded by in situ measurement using a laser device and then the mold of the structural plane is reproduced using a 3D printer. Subsequently, a mix proportion test of the high-strength mold material is conducted using the orthogonal test, and the model of the structural plane is prepared by pouring this high-strength mixture material into the 3D mold. Ultimately, the shear strength parameters of this high-strength structural plane replica are obtained using a shear box test in the laboratory. The proposed method has particular advantages such as the preparation of multiple replicas for structure planes and the ability to obtain repeatable results.