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  • Author: Chen Sheng x
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Chen Sheng, Zhao Dongbiao and Lu Yonghua

Abstract

For measurement of existing thread parameters using profile scanning, system error increases as pitch diameter, difference between the calibrating thread and measuring thread increases with the single gauge calibration method. There are several alignment deviations affecting the measurement of pitch diameter. To reduce the system error, a compensation method using two standard thread gauges to calculate the alignment deviations is proposed here. Finally, the theoretical and experimental comparisons between the single gauge calibration method and the proposed method are presented. The results demonstrate that the two gauges calibration method can effectively reduce the system error.

Open access

Yiwei Chen, Sheng-Hua Li and Bo Li

Abstract

The residual doses and sensitivity change for potassium-rich feldspar (K-feldspar) have been studied using the post-infrared infrared stimulated luminescence (pIRIR) and multi-elevated-temperature post-IR IRSL (MET-pIRIR) protocols. Laboratory simulated poorly-bleached and well-bleached samples were those K-feldspar grains bleached using a solar simulator for 10 minutes and 8 hours, respectively. The residual doses rise with stimulation temperature and time. The poorly-bleached sample has larger residual doses than the well-bleached sample, especially at high stimulation temperatures. The high-temperature pIRIR signals contain a large amount of hard-to-bleach signals. A decrease of luminescence sensitivity was observed after conducting a high-temperature-treatment in the measurement cycles. The sensitivity decreases significantly between the first and the second cycle. The extent of decrease in sensitivity shows a clear temperature trend. The higher the stimulation temperature of pIRIR signals is, the larger the sensitivity decreases. This decrease is more severe for the poorly-bleached sample than for the well-bleached sample, and could possibly lead to problems in sensitivity correction.

Open access

Xiu Sheng Wu, Ju Fang Cao, Zhi Jun Chen and Wei Liu

Abstract

The low-frequency mechanical spectra of lanthanum cobaltite based mixed conducting oxides have been measured using a computer-controlled inverted torsion pendulum. The results indicate that the internal friction spectra and shear modulus depend on the Sr doping contents (x). For undoped samples, no internal friction peak is observed. However, for La0.8Sr0.2CoO3‒δ, three internal friction peaks (P2, P3 and P4) are observed. In addition to these peaks, two more peaks (P0 and P1) are observed in La0.6Sr0.4CoO3‒δ. The P0 and P1 peaks show characteristics of a phase transition, while the P2, P3 and P4 peaks are of relaxation-type. Our analysis suggests that the P0 peak is due to a phase separation and the P1 peak is related to the ferromagnetic–paramagnetic phase transition. The P2, P3 and P4 peaks are associated with the motion of domain walls. The formation of this kind of domain structure is a consequence of a transformation from the paraelastic cubic phase to the ferroelastic rhombohedral phase. With partial substitution of Fe for Co, only one peak is observed, which is discussed as a result of different microstructure.

Open access

Jianping He, Weizhong Chen, Wusheng Zhao, Sheng Huang and Yunlong Yao

Abstract

Stress-strain mechanical properties of polystyrene foam plastic material were tested under different loading conditions. An empirical constitutive model for describing metal materials was proposed for the polystyrene plastic foam. The static and dynamic tests results show that the ductility and watertightness of the polystyrene plastic foam are significantly improved. At the same time, in order to check its seismic-isolation property, the high-performance foam concrete as filling materials of Galongla tunnel in Tibet was simulated by FEM. The simulated results show that the polystyrene plastic foam can remarkably decrease the stress and the plastic zone in final lining, so it can effectively reduce the seismic damage of the tunnel. Considering the seismic-isolation property and low price of polystyrene plastic foam, it is a good reference for the anti-seismic design of tunnels in high intensity zones.

Open access

Wen Xie, Hong Zhao, Yu Chen, Qin Zhang, Wei Lu, Wei Liu, Ai-rong Hu, Han-wei Li, Ping Feng, Ming-sheng Chen, Cun-jin Mei, Xiao-lin Guo, Xiao-hu Zhao, Jiang-bin Wang, Zheng-qin Fan, Jian-he Gan, Qing Xie and Jun Cheng

Abstract

Obejective Ademetionine 1,4-butanedisulfonate [S-adenosyl-L-methionine (SAMe)/Transmetil®, Abbott] has been available in China for more than 15 years, and it has been shown to reduce serum bilirubin and transaminase levels in viral hepatitis (VH) patients. However, no large-scale studies have focused on the impact of SAMe treatment regimen on reducing the serum total bilirubin (TBil) in VH patients with intrahepatic cholestasis (IHC). The primary purpose of this study was to evaluate the effectiveness of intravenous SAMe (Transmetil®) treatment in reducing the serum TBil by 50%.

Methods This retrospective, multi-center, cross-sectional medical record review involved patients aged ≥18 years. Records of 1 280 hospitalized VH patients at 16 sites diagnosed with IHC who had received intravenous SAMe 1 000 mg or 2 000 mg q.d. for at least 7 days from January 1, 2006 to June 30, 2009, were screened and 905 records were randomly selected.

Results The safety set (SS) included 834 patients and the full analysis set 826 patients. TBil levels after 14 days injection treatment were available for 763 patients. TBil decreased ≥ 50% versus baseline after 14 days treatment in 288 (37.7%) patients (95% CI 34.3%, 41.2%). Twenty-nine non-serious adverse events (non-SAEs) were reported in 19 (2.3%) patients, and 29 SAEs were reported in 10 patients (1.2%). All adverse events (AEs) were considered unrelated to the study drug.

Conclusions This retrospective study shows that intravenous SAMe administration in VH patients with IHC is associated with significant reduction of TBil levels in more than 30% of patients 14 days after treatment initiation.