In Liaoning, Hunan, Guangxi, Guizhou, Gansu, Sichuan, Anhui, Jilin and other provinces in China, there is a wide occurrence of metal quantity over 1000 tons of refractory gold ores, principally because of low gold rec...In Liaoning, Hunan, Guangxi, Guizhou, Gansu, Sichuan, Anhui, Jilin and other provinces in China, there is a wide occurrence of metal quantity over 1000 tons of refractory gold ores, principally because of low gold recoveries and become ＂stay mine＂. Features of refi＇actory gold ores are： gold in micro-particles or a microscopic state that is wrapped in pyrite, presence of arsenopyrite and other sulfide minerals or disseminated in the crystal lattice of sulfide minerals; harmful impurity elements such as arsenic, carbon, mercury, antimony, copper with high content are closely related with the gold, and these elements affect the contact reaction between the gold and solvent extraction, making the recovery of the gold extraction process low. In the past 20 years, overseas countries have developed the application of the roasting oxidation method, hot acid （alkali） oxidation, bacterial oxidation and flash chlorination oxidation technology to solve this problem.Among these, biological oxidation has developed rapidly in the domestic market and gold enterprises abroad because of its low investment in infrastructure, low production costs, less environmental pollution, simple process and easy control, etc.展开更多
The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentrat...The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentration values according to conversion factors that were worked out by simultaneous sampling in this study. The conversions were made so that exposure could be expressed in fiber-years (f-yr). Asbestosis was diagnosed on the basis of chest radiographs and occupational histories. Cumulative dust exposure (f-yr) was calculated up to the date of diagnosis for asbestosis patients, and up to September 1982 for the remaining workers. A dose-response relationship expressed as fiber-years exposed vs cumulative prevalence of asbestosis was established by the life table method on the basis of these data. Predicted 3 and 1% prevalence of asbestosis corresponded to 43 and 22 f-yr exposure, respectively. Considering that a worker can work for 35 years, these doses are commensurate with dust concentrations of 1.22 and 0.63 f/ml, respectively. It is recommended that 1 f/ml be taken as the maximum allowable concentration of airborne asbestos dust for the workplace with an anticipated prevalence of about 2% asbestosis after 35 years of exposure. 1990 Academic Press, Inc.展开更多
Writing fluently and expressively in English is a necessary skill for communication, as well as a required skill for Chinese students at the tertiary level. Since college students have already been trained on their Ch...Writing fluently and expressively in English is a necessary skill for communication, as well as a required skill for Chinese students at the tertiary level. Since college students have already been trained on their Chinese writing skills for a considerable length of time and are able to write in Chinese quite successfully, the application of contrastive rhetoric in the teaching of English writing is very effective. This paper explores the possibility of teaching English writing to Chinese students at the tertiary level and proposes an approach to this teaching model.展开更多
Objective: To explore the effect of traditional Chinese medicine (TCM) on abnormalmaternal-fetal immune and endocrine in 24cases of threatened abortion (TA) and 68 cases of recurrent spontaneous abortion (RSA).Methods...Objective: To explore the effect of traditional Chinese medicine (TCM) on abnormalmaternal-fetal immune and endocrine in 24cases of threatened abortion (TA) and 68 cases of recurrent spontaneous abortion (RSA).Methods: The levels of blocking effect (BE),antiidiotype antibody (AIA), cytotoxin antibody (CTA), β-human chorionic gonadotropin(β-hCG), progesterone (P), estradiol (E2)were measured in all 92 patients. Results: Incidence rates of the lack of BE, AIA and CTAin 92 cases were 60. 87%, 57. 61 % and 72.83% respectively. The lower levels of BE,AIA and CTA were elevated significantly (P< 0. 05 ～0. 01 ), and the serial levels β- hCG, P and E2 were markedly increasing (P< 0. 01 ) in all successful pregnant patients.The rate of the successful pregnancy of 92 cases was 89. 13 % (to TA 91. 67%, to RSA 88.24 % respectively). Conclusions: It suggeststhat the lack of blocking antibody (BA) andendocrine hormone deficiency may result inspontaneous abortion during early pregnancy.The therapeutic mechanism of those herbs intreating spontaneous abortion was associatedwith the growing levels of BA and hormone byregulating the maternal-fetal immunity and endocrine.展开更多
文摘In Liaoning, Hunan, Guangxi, Guizhou, Gansu, Sichuan, Anhui, Jilin and other provinces in China, there is a wide occurrence of metal quantity over 1000 tons of refractory gold ores, principally because of low gold recoveries and become ＂stay mine＂. Features of refi＇actory gold ores are： gold in micro-particles or a microscopic state that is wrapped in pyrite, presence of arsenopyrite and other sulfide minerals or disseminated in the crystal lattice of sulfide minerals; harmful impurity elements such as arsenic, carbon, mercury, antimony, copper with high content are closely related with the gold, and these elements affect the contact reaction between the gold and solvent extraction, making the recovery of the gold extraction process low. In the past 20 years, overseas countries have developed the application of the roasting oxidation method, hot acid （alkali） oxidation, bacterial oxidation and flash chlorination oxidation technology to solve this problem.Among these, biological oxidation has developed rapidly in the domestic market and gold enterprises abroad because of its low investment in infrastructure, low production costs, less environmental pollution, simple process and easy control, etc.
文摘The dose-response relationship for asbestos exposure in a chrysotile product factory was studied. The past gravimetric dust concentration values, obtained from different worksites, were converted into fiber concentration values according to conversion factors that were worked out by simultaneous sampling in this study. The conversions were made so that exposure could be expressed in fiber-years (f-yr). Asbestosis was diagnosed on the basis of chest radiographs and occupational histories. Cumulative dust exposure (f-yr) was calculated up to the date of diagnosis for asbestosis patients, and up to September 1982 for the remaining workers. A dose-response relationship expressed as fiber-years exposed vs cumulative prevalence of asbestosis was established by the life table method on the basis of these data. Predicted 3 and 1% prevalence of asbestosis corresponded to 43 and 22 f-yr exposure, respectively. Considering that a worker can work for 35 years, these doses are commensurate with dust concentrations of 1.22 and 0.63 f/ml, respectively. It is recommended that 1 f/ml be taken as the maximum allowable concentration of airborne asbestos dust for the workplace with an anticipated prevalence of about 2% asbestosis after 35 years of exposure. 1990 Academic Press, Inc.
文摘Writing fluently and expressively in English is a necessary skill for communication, as well as a required skill for Chinese students at the tertiary level. Since college students have already been trained on their Chinese writing skills for a considerable length of time and are able to write in Chinese quite successfully, the application of contrastive rhetoric in the teaching of English writing is very effective. This paper explores the possibility of teaching English writing to Chinese students at the tertiary level and proposes an approach to this teaching model.
文摘Objective: To explore the effect of traditional Chinese medicine (TCM) on abnormalmaternal-fetal immune and endocrine in 24cases of threatened abortion (TA) and 68 cases of recurrent spontaneous abortion (RSA).Methods: The levels of blocking effect (BE),antiidiotype antibody (AIA), cytotoxin antibody (CTA), β-human chorionic gonadotropin(β-hCG), progesterone (P), estradiol (E2)were measured in all 92 patients. Results: Incidence rates of the lack of BE, AIA and CTAin 92 cases were 60. 87%, 57. 61 % and 72.83% respectively. The lower levels of BE,AIA and CTA were elevated significantly (P< 0. 05 ～0. 01 ), and the serial levels β- hCG, P and E2 were markedly increasing (P< 0. 01 ) in all successful pregnant patients.The rate of the successful pregnancy of 92 cases was 89. 13 % (to TA 91. 67%, to RSA 88.24 % respectively). Conclusions: It suggeststhat the lack of blocking antibody (BA) andendocrine hormone deficiency may result inspontaneous abortion during early pregnancy.The therapeutic mechanism of those herbs intreating spontaneous abortion was associatedwith the growing levels of BA and hormone byregulating the maternal-fetal immunity and endocrine.
