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671.
杜丽冰 《环境技术》1998,16(1):29-32
在分析多区蜂窝CDMA系统干扰的基础上,提出了开,闭环结合的功控方式,要求和以载干比(CIR)为基础的功控算法,从而抑制干扰,改善系统性能,增加系统容量。  相似文献   
672.
Some lessons for the introduction of hydrogen fueled vehicles can be learned from experience gained by the introduction of natural gas fueled vehicles, either in Europe or in Argentina. While the European efforts have failed, at least until today, Argentina has achieved a remarkable market share of about 20% natural gas vehicles since the early 80ies. Beyond a short review on the constituents of a hydrogen refueling infrastructure, the Compressed Natural Gas (CNG)-example is analyzed to formulate some ‘must be’s’ for the successful introduction of hydrogen refueling infrastructure: Clear concerted signals have to be sent by all important players, the politicians as well as the involved industry from car producers to fuel suppliers. Bi-fueled hybrid vehicles are not seen as a proper tool, as they are forcing neither the user to look for hydrogen nor the supplier to provide hydrogen. After general considerations, various strategies and policies of different countries and manufacturers are reviewed. For instance, the electric hybrid cars as already today introduced by some Japanese manufacturers offer the chance of settling a maintenance infrastructure for electric drive systems already today which can be easily extended to cover full fuel cell drive systems, once they are available.  相似文献   
673.
An evaluation of mercury emissions from the chlor-alkali industry in China   总被引:3,自引:0,他引:3  
1 IntroductionThechlorine alkaliindustryisoneofthesubstantialpartsofthechemicalindustry .Now ,threetypesofelectrolyticcellsareusedtoproducechlorinegasandcausticsoda:theHgcell,thediaphragmcell,andthemembranecell.Chinaisusingthediaphragmcellasthemaintype.Na…  相似文献   
674.
采用曝气生物滤池与二氧化氯结合的工艺处理医疗废水,具有效果好,流程短,操作简便等优点,具有一定的推广价值。  相似文献   
675.
Human amniotic fluid cells exhibit a higher cloning efficiency and rate of cell proliferation when maintained on dishes coated with a naturally produced extracellular matrix (ECM) in comparison with the regular tissue culture plastic. In 22 out of 31 amniotic fluid samples there was by plating the cells on ECM a 2–6 fold increase in number and size of colonies and in the cell density per colony as detected by actual staining and viewing of each colony. These effects yielded, in 21 of 41 additional samples, a reduction ranging from 2–8 days, in the culture time elapsing between amniocentesis and the first harvesting of cells for chromosomal analysis. An even greater effect was obtained with primary cells that failed to attach to plastic surfaces and stayed floating in the medium but did attach and proliferate when seeded on ECM. Cells that were left firmly attached to ECM after the first trypsinization and harvesting of cells for chromosomal analysis yielded colonies ready for second karyotyping in less than half the time required for cells maintained on plastic. Studies with secondary cultures of human amniotic fluid cells have demonstrated a 5–10 fold decrease in serum requirement of cells cultured on ECM as compared with plastic. Addition of fibroblast growth factor (FGF) to the cultures further potentiated the effects of ECM. The ECM induced stimulation of cell attachment and proliferation was not associated with any chromosomal anomalies, nor did it interfere with the handling procedure. ECM coated dishes may be useful to reduce the time interval between amniocentesis and diagnosis, in particular when the amniotic cells exhibit an exceedingly slow rate of proliferation on plastic or when large quantities of cells are required for enzymatic studies.  相似文献   
676.
研究通过降解对苯二甲酸的酵母和细菌的复合处理,使TA的降解率达到95%以上,并生产了单细胞蛋白。该单细胞蛋白营养价值高,经急性和遗传毒性试验表明属实际无毒类,并不具遗传毒性,是优良的单细胞蛋白。  相似文献   
677.
应用电除尘与静电凝聚技术相结合,净化自焙阳极铝电解槽生产过程中所产生的有害气体和烟尘.有关部门测试认定,其沥青烟、氟化物和粉尘的排放量均低于国家排放标准.  相似文献   
678.
We report a case in which a discrepancy emerged between the prenatal diagnosis of female chromosomal sex and male sex at ultrasound examination. The FSH dosage performed on an amniotic fluid sample previously stored confirmed the male phenotype of the fetus. The effectiveness of the AF-FSH level dosage in prenatal diagnosis was taken into consideration.  相似文献   
679.
研究了硒化合物对长春花(C.roseus)细胞悬浮生长的影响.在pH5.5培养介质中,当Se(Ⅵ)>0.5ppm或Se(Ⅳ)>0.6ppm时,将抑制C.roseus细胞悬浮生长,其致死浓度分别是100ppm Se(Ⅵ)和2.0ppm Se(Ⅳ).C.roseus对硒化合物有效强的富集作用.硒化合物的毒性和培养介质的pH值有关.在本试验条件下,硒酸钠和亚硒酸钠对Hg2+无拮抗作用.  相似文献   
680.
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