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Your search keyword '"Zhang, Ren-Zhong"' showing total 26 results
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26 results on '"Zhang, Ren-Zhong"'

18. Effect of Al(OH)3on the properties of silica-based ceramic cores prepared by laser powder bed fusion combined with vacuum infiltration

Author

Liu, Heng, Zhang, Ren-Zhong, Wu, Jia-Min, Li, Wei-Kang, Zhou, Shi-Xiang, Zhang, Jie, Zheng, Wen, Yan, Chun-Ze, Wen, Shi-Feng, Ye, Chun-Sheng, Shi, Yu-Sheng, Chen, Chao-Yue, and Ren, Zhong-Ming

Abstract

Silica-based ceramic cores, with low coefficients of thermal expansion, low sintering temperatures, and excellent acid and alkali leaching capabilities, are essential materials for the production of hollow blades. However, their mechanical properties are suboptimal, and they present various processing challenges. In this study, silica-based ceramic cores were prepared using a combination of vacuum infiltration (VI) and laser powder bed fusion (LPBF) techniques. Al(OH)3was employed as a mineralizer to enhance the post-sintering mechanical properties and improve the efficiency of the vacuum infiltration process, thereby enhancing the overall performance of the silica-based ceramic cores. The VI process facilitated the penetration of nano-SiO2into the samples, increasing their density and promoting the formation of cristobalite during sintering at 1225°C. Additionally, the Al(OH)3powder, through pyrolysis into Al2O3during sintering, reduced microcracks, inhibited excessive cristobalite transformation, and improved the VI process, resulting in enhanced room-temperature flexural strength. By optimizing the Al(OH)3content and the VI process, significant improvements in the microstructure and properties of the silica-based ceramic cores were achieved. After three rounds of vacuum infiltration and the addition of 4 wt% Al(OH)3, the samples exhibited a high-temperature creep of 0.17 mm, with flexural strengths of 15.23 MPa at room temperature and 23.55 MPa at high temperature.

Published
2024
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24. [Estimation on the HIV-1 incidence among high risk groups using the pooling RNA technique].

Author

Dong LJ, Chen M, Su YZ, Li JJ, Zhang RZ, Yang L, Yang CJ, Shi YH, Chen HC, Chen L, Ma YL, and Jia MH

Subjects
Counseling, Humans, Incidence, Male, Mass Screening, HIV Infections epidemiology, HIV-1 genetics, Homosexuality, Male, RNA, Viral blood
Abstract

Objective: To timely identify the HIV-1 infection in window-period and to estimate the HIV-1 incidence among people who came for voluntary counseling and testing (VCT) service as well as men who have sex with men (MSM), respectively., Methods: HIV antibody negative samples that were determined by screening tests between January and October 2012, were collected and tested with pooling HIV-1 RNA testing technique (2-staged pooling by 50:1, 10:1). Positive cases were followed-up for HIV antibody testing while HIV incidence was calculated under Ron Brookmeyer' s method, among VCT and MSM populations., Results: Among 1400 HIV antibody negative samples of VCT, two showed HIV-1 RNA positive during the antibody window period with the HIV-1 incidence as 1.87% per year (95% CI: 1.23%-2.65% ). Among 500 HIV antibody negative samples from MSM population, two showed HIV-1 RNA positive in the antibody window period, with HIV-1 incidence as 5.31% per year (95% CI: 3.52%-7.45% )., Conclusion: Pooling HIV-1 RNA testing seemed a powerful tool for HIV antibody testing in the window-period. Measures should be taken to strengthen the HIV diagnostic programs among MSM and other high risk groups,during the HIV antibody window-period. More frequent detection approach as pooling HIV-1 RNA testing might be a good choice.

Published
2013

25. [Association of diabetes and early failure of arteriovenous fistula in the end stage of renal diseases].

Author

Cui TL, Zhang RZ, Liu F, Tang WX, Fu P, Zhou L, Tao Y, and Hu ZX

Subjects
Adult, Aged, Diabetic Nephropathies complications, Female, Humans, Kidney Failure, Chronic complications, Male, Middle Aged, Prospective Studies, Arteriovenous Shunt, Surgical adverse effects, Diabetic Nephropathies therapy, Hemofiltration methods, Kidney Failure, Chronic therapy
Abstract

Objective: To determine the association of diabetes and glycemic control with early failure of native arteriovenous fistula(AVF)., Methods: 266 patients with end stage renal diseases(ESRD) were recruited and divided into non-diabetic group (165), HbA1C < 7% group (51) and HbA1C > or = 7% group (50). Clinical indicators and early failure of AVF were examined., Results: In total, 63 (23.7%) patients had AVF early failure. The AVF early failure occurred in 18. 1% of patients in the non-diabetic group and 21.6% of patients in the HbA1C < 7% group, significantly less than that in the HbA1C > or = 7% group (44%). The COX regression model showed that increased HbA1C, total cholesterol (TC) and decreased high-density lipoprotein (HDL)increased the risk of AVF failure., Conclusion: The levels of glycemic and serum lipid subfractions are associated with AVF early failure in ESRD patients. Good control of glycemic and lipid can lower the rates of AVF early failure.

Published
2012

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