Research on Friction Characteristics of AlCrN and TiAlSiN Coatings and Properties of Coated Tools

Qi-Bin Yue,Hui-Bo He,Hua-Ying Li,Jun Zhang,Yuan-ming Li,Lu Ma 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.9

AlCrN and TiAlSiN coatings were deposited on the surface of 30CrMnSi steel and cemented carbide YT15 by multi-arc ion plating technique. A scanning electron microscopy was used to observe the surface morphologies of both coatings. The reciprocating sliding tests of AlCrN and TiAlSiN coating were performed to investigate the friction coefficients and the wear mechanisms of both coatings were analyzed as well. Dry machining tests on 30CrMnSi hardened steel were carried out with the AlCrN and TiAlSiN coated tools on a CA6140A lathe. The effects of cutting speed on cutting forces and cutting temperatures of AlCrN and TiAlSiN coated tools were obtained and analyzed. The microcosmic micrographs of wear areas of both coated tools were observed and investigated by scanning electron microscope and energy dispersive spectrum. The results show that the hardness and bonding strength of AlCrN coating are higher than that of TiAlSiN coating, while the friction coefficient of AlCrN coating is lower than that of TiAlSiN coating. Both the cutting force and cutting temperature of AlCrN coated tool are lower than TiAlSiN coated tool. The time required for the bluntness of the AlCrN coated tool is approximately 33.3% longer than that of the TiAlSiN coated tool, and the main wear mechanisms of both tools are mainly crater wear, diffusion wear and oxidation wear.

Clinical Characteristics and Survival Analysis of Breast Cancer Molecular Subtypes with Hepatic Metastases

Ge, Qi-Dong,Lv, Ning,Kong, Ya-Nan,Xie, Xin-Hua,He, Ni,Xie, Xiao-Ming,Wei, Wei-Dong Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.10

Background: The liver is one of the most common metastatic sites of breast cancer, hepatic metastases developing in 6%-25% of patients with breast cancer and being associated with a poor prognosis. The aim of this study was to analyze the survival and clinical characteristics of patients with hepatic metastases from breast cancer of different molecular subtypes and to investigate the prognostic and predictive factors that effect clinical outcome. Methods: We retrospectively studied the charts of 104 patients with breast cancer hepatic metastases diagnosed at Sun Yat-sen University Cancer Center from December 1990 to June 2009. Subtypes were defined as luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) enriched, triple-negative (TN). Prognostic factor correlations with clinical features and treatment approaches were assessed at the diagnosis of hepatic metastases. Results: The median survival time was 16.0 months, and the one-, two- three-, four-, five-year survival rates were 63.5%, 31.7%, 15.6%, 10.8%, and 5.4%, respectively. Median survival periods after hepatic metastases were 19.3 months (luminal A), 13.3 months (luminal B), 18.9 months (HER2-enriched), and 16.1 months (TN, P=0.11). In multivariate analysis, a 2 year-interval from initial diagnosis to hepatic metastasis, treatment with endocrine therapy, and surgery were independent prognostic factors. Endocrine therapy could improve the survival of luminal subtypes (P=0.004) and was a favorable prognostic factor (median survival 23.4 months vs. 13.8 months, respectively, P=0.011). Luminal A group of patients treated with endocrine therapy did significantly better than the Luminal A group of patients treated without endocrine therapy (median survival of 48.9 vs. 13.8 months, P=0.003). Conclusions: Breast cancer subtypes were not associated with survival after hepatic metastases. Endocrine therapy was a significantly favorable treatment for patients with luminal subtype.

Statistics-based Optimization of Extracellular Polysaccharide Production from Hirsutella sinensis using a Fermentation Process and In vitro Immunomodulatory Activity

Liang He,Jun-Wen Cheng,Yan-Bin Wang,Hai-Bo Li,Hua Qian,Wei-Qi Li,Xue-Yong Ren 한국식품과학회 2014 Food Science and Biotechnology Vol.23 No.2

A 3 factor, 3 level Box-Behnken factorialdesign combined with response surface methodology wasused to optimize the fermentation process for production ofextracellular polysaccharide (EPS) from Hirsutella sinensis. The 3 independent variables were temperature (X1), initialpH (X2), and the glucose concentration (X3). Experimentaldata were fitted to a 2nd order polynomial equation usingmultiple regression. The optimal fermentation conditionsof the production of EPS were a temperature of 18.21oC,an initial pH of 5.81, and a glucose concentration of 7.39g/L. The maximum predicted EPS production of 2.41 g/Lwas close to the actual experimental EPS yield (2.42±0.038%), demonstrating the model validity. EPS from H. sinensis had a direct in vitro immuno-stimulating activityusing murine macrophage RAW264.7 cells, and stimulatedrelease of several major cytokines (IL-1β, NF-κB, TNF-α,and iNOS) in a dose-dependent manner.

Full-scale testing and modeling of the mechanical behavior of shield TBM tunnel joints

Wen-qi Ding,Yi-cheng Peng,Zhi-guo Yan,Bi-wei Shen,He-hua Zhu,Xin-xin Wei 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.3

For shield TBM (Tunnel Boring Machine) tunnel lining, the segment joint is the most critical component for determining the mechanical response of the complete lining ring. To investigate the mechanical behavior of the segment joint in a water conveyance tunnel, which is different from the vehicle tunnel because of the external loads and the high internal water pressure during the tunnel’s service life, full-scale joint tests were conducted. The main advantage of the joint tests over previous ones was the definiteness of the loads applied to the joints using a unique testing facility and the acquisition of the mechanical behavior of actual joints. Furthermore, based on the test results and the theoretical analysis, a mechanical model of segment joints has been proposed, which consists of all important influencing factors,including the elastic-plastic behavior of concrete, the pre-tightening force of the bolts and the deformations of all joint components, i.e., concrete blocks, bolts and cast iron panels. Finally, the proposed mechanical model of segment joints has been verified by the aforementioned full-scale joint tests.

Polymorphisms in TYMS for Prediction of Capecitabine-Induced Hand-Foot Syndrome in Chinese Patients with Colorectal Cancer

Si-Qi Dong,Tong-Min Wang,Jiang-Bo Zhang,Yong-Qiao He,Wen-Qiong Xue,Zi-Yi Wu,Da-Wei Yang,Lian-Jing Cao,Jing-Wen Huang,Xi-Zhao Li,Pei-Fen Zhang,Xiao-Hui Zheng,Wei-Hua Jia 대한암학회 2021 Cancer Research and Treatment Vol.53 No.3

Purpose Capecitabine is an extensively used oral prodrug of 5-fluorouracil in treatment of colon cancer and is known to cause hand-foot syndrome (HFS). As the target enzyme for capecitabine, thymidylate synthase (TYMS) plays a key role for 5-fluorouracil metabolism and has been associated with some side effects caused by capecitabine. The aim of our study is to identify the possible genetic predictors of capecitabine-induced HFS (CAP-HFS) in Chinese colorectal cancer patients.Materials and Methods Whole exons of TYMS were sequenced for 288 extreme phenotype HFS patients, including 144 severe or early-onset (first 2 cycles) moderate HFS extreme cases and 144 extreme controls with no reported HFS. The associations between polymorphisms and CAP-HFS were analyzed using logistic regression under an additive model.Results We identified a novel risk mutation (c.1A>G, chr18:657743), was associated with severe HFS in an extreme case who was affected during the first cycle of treatment. Moreover, we identified three new variants, rs3786362, rs699517, rs2790, and two previously reported variants, 5’VNTR 2R/3R and 3′-untranslated region 6-bp ins-del, which were significantly associated with CAP-HFS (p < 0.05). In silico analysis revealed that the effect of these polymorphisms in the TYMS region on the development of HFS might not be restricted solely to the regulation of TYMS expression, but also the TYMS catalytic activity through the indirect effect on ENOSF1 expression.Conclusion This study identified new polymorphisms in TYMS gene significantly associated with CAP-HFS, which may serve as useful genetic predictors for CAP-HFS and help to elucidate the underlying mechanism of HFS.

Progress of Study on Mesogen-Jacketed Liquid Crystalline Polymers at Peking University

Xing-He Fan,Xiao-Fang Chen,Xin-Hua Wan,Er-Qiang Chen,Qi-Feng Zhou 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.10

An improved extended Kalman filter for parameters and loads identification without collocated measurements

Jia He,Mengchen Qi,Zhuohui Tong,Xugang Hua,Zhengqing Chen 국제구조공학회 2023 Smart Structures and Systems, An International Jou Vol.31 No.2

As well-known, the extended Kalman filter (EKF) is a powerful tool for parameter identification with limited measurements. However, traditional EKF is not applicable when the external excitation is unknown. By using least-squares estimation (LSE) for force identification, an EKF with unknown input (EKF-UI) approach was recently proposed by the authors. In this approach, to ensure the influence matrix be of full column rank, the sensors have to be deployed at all the degrees-offreedom (DOFs) corresponding to the unknown excitation, saying collocated measurements are required. However, it is not easy to guarantee that the sensors can be installed at all these locations. To circumvent this limitation, based on the idea of first-orderholder discretization (FOHD), an improved EKF with unknown input (IEKF-UI) approach is proposed in this study for the simultaneous identification of structural parameters and unknown excitation. By using projection matrix, an improved observation equation is obtained. Few displacement measurements are fused into the observation equation to avoid the so-called low-frequency drift. To avoid the ill-conditioning problem for force identification without collocated measurements, the idea of FOHD is employed. The recursive solution of the structural states and unknown loads is then analytically derived. The effectiveness of the proposed approach is validated via several numerical examples. Results show that the proposed approach is capable of satisfactorily identifying the parameters of linear and nonlinear structures and the unknown excitation applied to them.

Efficacy and Safety of Intravenous Urapidil for Older Hypertensive Patients with Acute Heart Failure: A Multicenter Randomized Controlled Trial

Wei Yang,Qi Hua,Yu-Jie Zhou,Yan Fu,Jian Qin,Shu Qin,Xiao-Min Chen,Jin-Cheng Guo,De-Zhao Wang,Hong Zhan,Jing Li,Jing-Yu He 연세대학교의과대학 2017 Yonsei medical journal Vol.58 No.1

Purpose: Urapidil is putatively effective for patients with hypertension and acute heart failure, although randomized controlled trials thereon are lacking. We investigated the efficacy and safety of intravenous urapidil relative to that of nitroglycerin in older patients with hypertension and heart failure in a randomized controlled trial. Materials and Methods: Patients (>60 y) with hypertension and heart failure were randomly assigned to receive intravenous urapidil (n=89) or nitroglycerin (n=91) for 7 days. Hemodynamic parameters, cardiac function, and safety outcomes were compared. Results: Patients in the urapidil group had significantly lower mean systolic blood pressure (110.1±6.5 mm Hg) than those given nitroglycerin (126.4±8.1 mm Hg, p=0.022), without changes in heart rate. Urapidil was associated with improved cardiac function as reflected by lower N terminal-pro B type natriuretic peptide after 7 days (3311.4±546.1 ng/mL vs. 4879.1±325.7 ng/mL, p=0.027) and improved left ventricular ejection fraction (62.2±3.4% vs. 51.0±2.4%, p=0.032). Patients given urapidil had fewer associatedadverse events, specifically headache (p=0.025) and tachycardia (p=0.004). The one-month rehospitalization and all-cause mortality rates were similar. Conclusion: Intravenous administration of urapidil, compared with nitroglycerin, was associated with better control of blood pressure and preserved cardiac function, as well as fewer adverse events, for elderly patients with hypertension and acute heart failure.

Research on the Cutting Performances and Wear Mechanisms of TiAlCrN Coated Tools during Dry Turning

Hui-Bo He,Hua-Ying Li,Xian-Ying Zhang,Qi-Bin Yue,Jun Zhang,Lu Ma,Yuan-ming Li 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.2

Physical vapour deposition technique was used to deposit TiAlCrN coatings on the YT15 tungsten carbide inserts. The dry turning tests of 20CrMo steel were carried out to evaluate performances of TiAlCrN coated and uncoated tools on the CA6140A lathe. The effect of the two kinds of tools on cutting forces, cutting temperature, surface roughness and tool wear had been investigated to assess the performance of TiAlCrN coated tools. The results showed that the cutting force and cutting temperature obtained by TiAlCrN coated tools were decreased and the TiACrN coated tools produced a better surface finish in comparison with the uncoated tools. The TiAlCrN coated tools yield working life about 45 min, which was two times of that for uncoated tools. The wear mechanisms of the TiAlCrN coated tools were mainly oxidation and boundary wear, accompanied with diffusion wear.

Optimal Design of a Tilling Machine Reduction Gearbox Using Matlab

Hui-Bo He,Hua-Ying Li,Sung-Ki Lyu,Sung-Hoon Tak,Sung-Min Moon,Qi Zhang 한국정밀공학회 2009 International Journal of Precision Engineering and Vol.10 No.2

This paper describes the optimal design of the reduction gearbox of a tillage machine. The minimum center diameter was selected as the objective, and the contact fatigue strength. bending fatigue strength, condition of nonintervention, and oil film thickness ratio of the gearbox were applied as constraint conditions. The optimal model was solved by a Matlab program. The results show that the center diameter of the reduction gearbox decreased by about 10%. The resulting decrease in weight and volume led to a reduction in the amount of gearbox matelial and a consequent decrease in production cost.