Showing papers by "Chao Zhang published in 1999"

Dynamic Prognostic Prediction of Defect Propagation on Rolling Element Bearings

Abstract: Rolling element bearing failure is a major factor in the failure of rotating machinery. Current methods of bearing condition monitoring focus on determining any existing fault presence on a bearing as early as possible. Although a defect can be detected when it is well below the industry standard of a fatal size of 6.25 mm2 (0.01 in2), the remaining life of a bearing (the time it takes to reach the final failure size) from the point where a defect can be detected can vary substantially. As a fatal defect is detected, it is common to shut down machinery as soon as possible to avoid catastrophic consequences. Performing such an action, which usually occurs at inconvenient times, typically results in substantial time and economics losses. It is, therefore, important that the bearing's remaining life be more precisely forecasted, in a prognostic rather than diagnostic manner, so that maintenance can be optimally scheduled. Unfortunately, current bearing remaining life prediction methods have not been well dev...

Preparations and properties of some phosphorus- containing dialdehydes and dialcohols

Abstract: Di(4-formyl-2-methoxyphenyl)phosphates (DFMPP) were synthesized by the condensation of vanillin with phosphoryldichlorides. The di(4-hydroxymethyl-2-ethoxyphenyl)phosphates (DHMPP) were prepared by the reduction of DFMPP with potassium borohydride. The 31P-1H coupling in DFMPP (compounds 1a-h) was investigated and the splitting of the 31P signal by the 1H nuclei was observed only with the alkyl DFMPP (1a-e). In the non-decoupled 31P spectra a quartet at −11.3 ppm was seen for la (P-OCH 3) with JPH=11.4 Hz, and a triplet for 1b, 1c, 1d and 1e respectively (1b, P-OCH 2 δ= - 12.3 ppm, JPH=8.4 Hz; 1c, P-OCH 2CH2CH3, δ= - 12.6 ppm, JPH=7.1 Hz; 1d, P-OCH 2CH2CH2CH3, δ= - 12.9 ppm, JPH=8.4 Hz and le, P-OCH 2CH2Cl, δ= - 13.0 ppm, JPH = 8.1 Hz).

Study on the inhibition of nude mice transplantation tumor growth by telomerase ribozyme

Abstract: OBJECTIVE To explore whether telomerase ribozyme could inhibit the growth of nude mice transplantation tumor. METHODS A xenograft human-nude mouse model was constructed. A total of 24 mice were divided into 4 groups, namely, the saline control(Group 1), the blank plasmid control(Group 2), the 20 microg/mouse/day p(XJ-neo-teloRZ)(Group 3) and the 30 microg/mouse/day p(XJ-neo-teloRZ)(Group 4). All plasmids were packaged by lipofectamine and used for subcutaneous, continuous infusions over 14 days. Tumor measurements and observations of animal behavior were recorded daily. On completion of the study, the mice were killed by cervical dislocation and their organs were removed, weighed, and stored in formaldehyde for histological examination. The telomerase activities of tumor tissues of each group were also detected. RESULTS The telomerase ribozyme effectively inhibited the telomerase activities of tumor tissues and promoted the apoptosis of tumor cells. The in vivo studies showed a significant decrease in tumor size in mice treated with p(XJ-neo-teloRZ) when compared to the mice treated with controls. Furthermore, the in vivo effect of p(XJ-neo-teloRZ) was dose dependent. CONCLUSION Telomerase ribozyme is a powerful telomerase inhibition agent; probably it could be effective in tumor gene therapy.