首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
INTRODUCTIONMostparoxysmalatrialfibrillationisactivatedbyatrialectopiesoriginatinginthepulmonaryveins.Severalresearchesdemonstratedthatal most 50 %offocalatrialfibrillationoriginatesintheleftsuperiorpulmonaryveinandabout3 0 %intherightsuperiorpulmonaryvei…  相似文献   

2.
INTRODUCTION In powder compaction, the characteristics ofthe powder affect the compaction behavior and thequality of the pressed green body and its relativedensity, porosity, pore size distribution, sinteringand the consequent microstructure of the final sin-tered body. Superfine powder is prerequisite forpreparing high performance ceramic materials (Liu,1996; Lange et al., 1983; Lange, 1989). At present,most of the chemosynthesis methods are not suit-able for preparing industrial …  相似文献   

3.
Jar tests were conducted to investigate the performance of enhanced primary treatment processes for low-concentra-tion municipal wastewater from South China by using composite flocculant combined with bio-flocculants Pullulan and poly-aluminum-chloride (PAC). The optimum dosage for composite flocculant and conditions for flocculation were determined. The experimental results indicated that composite flocculant had high efficiency for removing over 95% of turbidity, over 58% of CODCr (chemical oxygen demand determined with potassium dichromate), over 91% of TP (total phosphate), and over 15% of NH3-N. Moreover, it could improve sludge settling and dehydration properties, and decrease the treatment cost.  相似文献   

4.
Removal of cyclops in pre-oxidizing cooperation water treatment process   总被引：1，自引：0，他引：1  
Zooplankton cyclops propagates profusely in waterbody, cannot be effectively inactivated by conventional disinfec- tion process, and becomes a troublesome drinking water treatment problem. In this work, the qualitative and quantitative ex- perimental studies were carried out on inactivation of zooplankton cyclops using oxidants, such as chlorine (Cl2), chlorine dioxide (ClO2), ozone (O3), hydrogen peroxide (H2O2), ozone/hydrogen peroxide (O3/H2O2), chloramines (Cl2-NH3) and potassium permanganate (KMnO4). The influences of various factors include different oxidant dosages, organic substance contents and pH values. The results showed that currently available oxidants used all might inactivate cyclops in some extent. According to the experimental results, chlorine dioxide, ozone, ozone/hydrogen peroxide and chloramines can be selected as effective oxidants for inactivating cyclops because of their strong inactivation abilities. Then the synergic removal effects on cyclops with ozone, ozone/hydrogen peroxide pre-oxidation followed by conventional water treatment processes were investigated. The results showed that ozone and ozone/hydrogen peroxide pre-oxidation can inactivate cyclops effectively, which then can be removed thoroughly by conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.65 mg/L of ozone and 6 mg/L of hydrogen peroxide, with the inactivation rate being 62% before conventional water treatment processes. Cyclops cannot appear in water after filtration with 1.8 mg/L of ozone, with the inactivation rate being 50% before conventional water treatment processes. For different oxidants, when removal rate was the best, the inactivation rate was not the same. These results may pro- vide reference and model for actual waterworks.  相似文献   

5.
This study investigated the removal and transformation of organic matter through laboratory-scale soil-aquifer treatment (SAT) soil columns over a 110-day period. Reductions in total organic carbon (TOC), dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC), nonbiodegradable dissolved organic carbon (NBDOC) and absorbance of ul-traviolet light at 254 nm (UV-254) averaged 71.46%, 68.05%, 99.31%, 33.27% and 38.96% across the soil columns, respectively. DOC/TOC ratios increased slightly with depth while BDOC/DOC ratios showed a converse trend. DOC exiting the soil-column system contained only a very small biodegradable fraction. SAT decreased the concentration of DOC present in feed water but increased its aromaticity, as indicated by specific ultraviolet light absorbance (SUVA), which increased by 50%～115% across the soil columns, indicating preferential removal of non-aromatic DOC during SAT. Overall, laboratory-scale SAT reduced triha-lomethane formation potential (THMFP), although specific THMFP increased. THMFP reduction was dominated by removal in chloroform. All samples exhibited a common general relationship with respect to weight: chloroform>dichlorobromomethane >dibromochloromethane>bromoform.  相似文献   

6.
In this paper, the characteristics of integrated biological aerated filter （IBAF） applied to municipal wastewater treatment were studied in a pilot scale experiment. The experimental results showed that IBAF has high efficiencies in removing organic pollutants, such as CODCr and SS, in municipal wastewater. The removal rates of CODCr and SS can reach over 90% and 80%, respectively, when COD and SS in the influent are 234 mg L^-1 and 112 mg L^-1, hydraulic retention time （HRT） is 8 h, and the aerated intensity is in the range of （0.5 to 0.6） L m^-2 s^-1.  相似文献   

7.
Gallbladder cancer has a poor outcome because of its anatomy and location. Often, the diagnosis is made very late due to its silent course. Post-operated cases do respond to chemotherapy but the survival is counted in months and the quality of life is further hampered due to toxicity of drugs. Immunotherapy holds good promise in non-responding cancers treated by conventional chemotherapeutic agents. Among various therapies, dendritic cell therapy is growing at rapid pace due to its acceptable rationale. It has been utilized in treating successfully resected stage Ill （T2, N1, M0） gallbladder cancer in one of our patients. A 48 years old lady treated with this therapy is free of metastasis with ten doses of autologous dendritic cell vaccine constructed by utilizing resected tumor lysate antigen. She has received ten doses of therapy in 14 months of her treatment. This therapy has proven to be safe and without apparent side effects. The positive clinical response obtained supports that autologous dendritic cell-based immunotherapy is a promising therapeutic approach for refractory gallbladder cancers.  相似文献   

8.
Prior research has linked substance abuse and antisocial behavior. This study uses structural models to examine developmental stages of antisocial behavior and their relation to during‐treatment performance of probationers in a 4‐month inpatient program. Separate childhood and adulthood antisocial functioning components were identified, and each predicted during‐treatment psychological functioning and program perceptions. Specifically, adulthood hostility predicted psychological functioning, and adulthood risk‐taking predicted program perceptions; the effect of childhood antisocial behavior was completely mediated by adulthood functioning.  相似文献   

9.
Objective: To study the diagnosis and treatment of pheochromocytoma in urinary bladder. Methods: Six cases of bladder pheochromocytoma were studied. Four cases showed hypertension, 3 of which were paroxysmal hypertension during urination. Catecholamine (CA) was increased in a case, and vanillymandelic acid (VMA) was increased in 2 cases. Bladder sub- mucosal mass was detected by B-ultrasound in 5 cases (5/5), computerized tomography (CT) in 3 cases (3/3), cystoscopy in 5 cases (5/6). Four cases took α-receptor blocker for 2 weeks, 1 case took β-receptor blocker to decrease heart rate. All patients were treated with surgical operation including 4 partial cystectomies, 2 excavations. Results: Three cases had manifestations including headache, excessive perspiration and hypertension during cystoscopy. Four cases were confirmed before operation. Two cases showed hypertension during operation. All patients were pathologically diagnosed as pheochromocytoma post- operatively. In five cases followed up, blood pressure returned to normal. No patient had relapse and malignancy. Conclusions: Typical hypertension during urination comprised the main symptoms. We should highly suspect bladder pheochromocytoma if a submucosal mass was discovered with B-ultrasound, CT, 131I-MIBG (methyliodobenzylguanidine) and cystoscopy. The deter- mination of CA in urine is valuable for qualitative diagnosis. The preoperative management of controlling blood pressure and expansion of the blood volume are very important. Surgical operation is a good method for effective treatment. Postoperative long-time followed up is necessary.  相似文献   

10.
INTRODUCTION Chlorinated hydrocarbons, a class of widely used dry-cleaning liquids, industrial organic solvents, and degreasers, increasingly find their way into drinking water sources, thus posing a very serious health and environmental problem (Love and Eliers, 1982). These organic solvents are known for their stability in the environment and cancer-causing po- tency and cannot be effectively and economically eliminated by current conventional treatment tech- nologies. One of the few av…  相似文献   

11.
Objective： To evaluate the efficacy and the indication of basic fibroblast growth factor （bFGF） in the treatment of exposure of orbital implants. Design： Retrospective and observational case series. Methods： We reviewed 41 patients （41 eyes） suffering exposure of orbital implants from Jan. 2000 to June 2006. The study group patients with mild exposure received combined treatment with bFGF and antibiotic drops, and while the control group patients with mild exposure were treated with antibiotic drops only. The study group patients with moderate and severe exposure received combined treatment with bFGF and antibiotic drops, and after 2 months they were subjected to amniotic membrane transplantation, while the control group patients with moderate and severe exposure underwent amniotic membrane transplantation after using antibiotic drops. Observation of the growth of conjunctival epithelium and comparison of the healing rate of the two groups. Results： The healing rates of the mild, moderate and severe exposure study group were 100% and 92.3%. The healing rates of the mild, moderate and severe exposure control group were 55.6% and 66.7% respectively. The difference of the healing rates of the mild exposure study group and the control group was significant （P=-0.033）. And the difference of the healing rates of the moderate and severe exposure study group and the control group was not significant （P=-0.167）. Conclusion： bFGF may promote obviously the healing of orbital implant exposure, particularly it can be the first choice for the treatment of mild degree exposure. For the moderate and severe cases, it can be administered before surgical repair to enhance neovascularization and will tend to increase the success rate of surgical repair.  相似文献   

12.
INTRODUCTION In cancer patients, tumor immunity is generally impaired. However, tumor immunity may occur in-vivo as circulating tumor-specific antibodies, with cytotoxic T lymphocytes (CTLs) having been identi- fied in cancer patients (Disis et al., 1997; Albert et al., 1998) suggesting that effective anti-tumor responses may be elicited through immunotherapeutic strategies. In recent years, a number of clinical trials have proved the safety and feasibility of using human dendritic cell…  相似文献   

13.
1 Introduction a Water pollution is quite severe in China. According to the statistical data of The Environmental Protection Ministry of China in 2003, the whole wastewater discharge came to 4.46 × 1014t all over the country. 46.2% in that were industrial wastewater and 53.8% were sewage. In 407 environmental monitoring sections of the seven main rivers of China in 2003, only 38.1% of the tested sections accorded with the the national water quality standard of Grade III, and 29.7% of the …  相似文献   

14.
INTRODUCTION Coagulation-flocculation is a major step inthe potable water treatment for removal of colloi-dal impurity. Due to the increase of water pollu-tion, the standards of drinking water supply andwastewater discharge are becoming more and morestringent, and chemical coagulants that are moreefficient in water treatment are more and moreurgently in demand. As well known, the residual Al in potablewater comes from three main sources: natural wa-ter-body, coagulants used in…  相似文献   

15.
In solving the deterioration of biological treatment system treating petrochemical wastewater under low temperatures, bioaugmentation technology was adopted by delivering engineering bacteria into a pilot-scale two-stage anoxic-oxic (A/O) process based on previous lab-scale study. Experimental results showed that when the concentrations of COD and NH4 -N of the influent were 370~910 mg/L and 10~70 mg/L, the corresponding average concentrations of those of effluent were about 80 mg/L and 8 mg/L respectively, which was better than the Level I criteria of the Integrated Wastewater Discharge Standard (GB8978-1996). According to GC-MS analysis of the effluents from both the wastewater treatment plant (WWTP) and the pilot system, there were 68 kinds of persistent organic pollutants in the WWTP effluent, while there were only 32 in that of the pilot system. In addition, the amount of the organics in the effluent of the pilot system reduced by almost 50% compared to that of the WWTP. As a whole, after bioaugmentation, the organic removal efficiency of the wastewater treatment system obviously in- creased.  相似文献   

16.
This commentary focuses on the conceptual implications of analyses of individual differences in francophone post-Piagetian research. These analyses are viewed as preoccupied by the "American question" of measurement and method, instead of attempting a theoretical account of the issues raised by intraindividual and interindividual variability in development.  相似文献   

17.
Substituted plan in EIA mainly means a the treatment technology and the substituted site of wastewater plant, and it also includes the many kinds of environment protection measures. In principal, the substituted plan should reach the same aim and achieve …  相似文献   

18.
INTRODUCTION Due to market pressures for improvements in productivity, reliability, ductility, wear resistance and profitability of mechanical systems, manufacturers are placing increasing demands on available materials.Economic constraints require that these materials are inexpensive and easily available. In order to enhance the surface properties of today’s materials, producers of components are turning to different surface finish and treatments. There are several techniques available …  相似文献   

19.
INTRODUCTIONInordertogetpliableandelegantterylenefabricjustlikesilk,terylenegreigeclothisalwayspretreatedwithalkali-decompositionprocesswh-ereinterylenegreigeclothishydrolyzedtosomeextentinNaOHsolutionatcertaintemperature(T)andpressure.Duringthisprocess,thesuperficialterylenefibreispeeledofffromtheclothanddis-solvedintosolution,inwhichteryleneacid(TA)andethyleneglycolaredischargedaspollutantsinwastewater.Theobtainedterylenefabricwithsi-lkenwrinkleandsoftfeelingiscalledartificialsilkfabr…  相似文献   

20.
The self-fulfilling prophecy model of Brophy and Good was applied to the area of teacher judgement in order to disclose the processes of how teacher judgement of student achievement influences students’ future academic outcomes. It was assumed that achievement and achievement motivation might be affected through the mediating processes of student-perceived positive and negative teacher treatment, which represents students’ perceptions of teachers’ actions towards them. A sample of 294 Chinese fifth-grade students and their eleven English language teachers were tracked over one school year. Structural equation modelling showed that after controlling for prior achievement and achievement motivation, teacher judgement was directly related to students’ future achievement, expectancy for success and level of aspiration. These relations were partially mediated by perceived negative teacher treatment. Teacher judgement was related to students’ academic self-concept and pride in English learning, and fully mediated by both perceived positive and negative teacher treatment. The study supported the model of Brophy and Good and identified the specific processes of how teacher judgements can become self-fulfilled. Positive and negative teacher treatment had different mediating effects. Compared with positive teacher treatment, perceived negative treatment was related to student academic outcomes more extensively.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号