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单纯的氯化钙沉淀法不能把含氟量较高的转炉浊环水中的氟含量降低到较低水平,氯化钙与PAC(Al2(SO4)3)的混合沉降法可以将含氟量如此高的OG水中的氟降低到40 mg/L以下。其中,PAC的处理效果优于Al2(SO4)3,在p H值范围8.0~8.5时,氯化钙投加量为3000~3500 mg/L,PAC投加2~3mg/L的条件下,沉降1.5~2 h,处理后的水中氟含量可达40 mg/L以下。 相似文献
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长江中游某地下水氟质量浓度为2~4 mg/L,不满足饮用水源要求。研究了用活性氧化铝作除氟剂,从此地下水中除氟,考察了活性氧化铝加入量、吸附时间、吸附温度、地下水pH对除氟效果的影响。结果表明:对氟质量浓度2.53 mg/L的原水,在粒度为?1~2 mm氧化铝用量24 g/L、吸附温度20℃、吸附时间2 h静态吸附条件下,水中氟质量浓度可降至0.90 mg/L,氟去除率为64.43%;在原水流速5 BV/h、20℃、通水量190 BV动态吸附条件下,出水F~-平均质量浓度为0.70 mg/L,氟质量浓度符合饮用水标准(GB 5749—2006)要求。 相似文献
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从结晶器下口出来的含氟连铸保护渣熔渣与二冷水接触过程中,大量的离子释放到水中导致水质发生改变,呈酸性的二冷水不仅加速了连铸设备的腐蚀,水中大幅增加的F-还会导致水污染。为了研究连铸保护渣熔渣对水质产生影响的机制,通过熔渣水浸实验研究了无氟、低氟和高氟连铸保护渣水浸过程中水质的变化规律。水浸实验结果表明,无氟保护渣熔渣水浸实验过程中水样的pH值在7~10之间;低氟保护渣水样的F-质量浓度为5~7 mg/L,pH值在7~10之间;而高氟保护渣水样的F-质量浓度高达35 mg/L,pH值在4~10之间。保护渣中阳离子通过离子交换溶出导致水样呈碱性,而F-的交换溶出则会导致水样呈酸性,因此,水样的pH值则是由两类离子交换过程共同决定。无氟或低氟保护渣中由于氟的降低而减少了F-的交换溶出,从而抑制了氟造成的水污染及强腐蚀性的酸性二冷水的生成。 相似文献
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针对某铅锌选矿废水采用HQW-A+HQW-B+HQW-C+催化氧化体系可以有效降COD、除氟。试验结果表明:当HQW-A用量300 g/m~3,HQW-B用量1 700 g/m~3,HQW-C用量2 g/m~3时,可将用井下水选矿的尾水中的氟从8.4 mg/L降至1.2 mg/L,COD从45.6 mg/L降至17.6 mg/L;可将用新鲜水选矿的尾矿水中的氟从4.7 mg/L降至1.2 mg/L,COD从58.8 mg/L降至10.0 mg/L。该水处理体系操作简单,使用方便,有较为明显的社会环境效益。 相似文献
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在模拟的合成硫酸锌溶液中,采用氧化铅作为除氟剂,研究了反应温度、溶液初始氟浓度、杂质镁离子及氯离子对除氟过程的影响。结果显示,反应温度及氯离子对除氟效率有较大影响,且初始氟浓度越高,氧化铅单位除氟量越高。当反应温度为80 ℃、锌浓度120 g/L、初始氟离子浓度250 mg/L时,溶液的除氟率最高,达到76%以上。采用企业的锌电解液对氧化铅除氟的适用性进行了验证,表明氧化铅也具有较好的除氟效果。在实际溶液的初始氟浓度为200 mg/L、锌浓度160 g/L时,120 min后,氟离子浓度降至95 mg/L,除氟率高于50%。在一段反应时间内,氟离子浓度随时间变化具有较好的线性关系。 相似文献
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以重庆大学、重庆邮电大学和重庆理工大学为例,剖析重庆高校推进产学研合作的基本模式,已经取得的突出成绩,分析总结其基本经验.从完善政策法规体系、强化经济调控、建立组织机构、加强中介建设及开展国际产学研合作等方面,提出了深入推进重庆高校产学研合作的对策建议. 相似文献
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The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine. 相似文献
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A prospective study of fractures in 231 children received at Khartoum North Teaching Hospital(KNTH) was carried out for a period of six months. The incidence of child fracture rated as one per day, then it increased from the age of 5 years onwards in boys and between 6 and 8 years in girls. Most injuries were sustained during the day time, especially between late afternoon and sunset. 82% of injured children presented to a medical facility, while 18% were taken to native healers first. Non-road traffic accidents accounted for 84% of the fractures mainly due to sports, domestic injuries and falls; whereas road traffic accidents were 16% and occurred mainly in pedestrians. Forty three percent of the fractures needed only first aid and splintage while 42% needed closed reduction. Thirty one percent of all patients were treated as inpatients. The long bones were affected in 91% of all fractures, the commonest site being the distal end of the forearm (26%), followed by supracondylar fracture of the humerus (15.6%). In the upper limb, left-sided fractures predominated. The epiphyseal injuries were 3.5% of all fractures, mainly at the distal radial epiphysis. Boys were commonly affected between 13-15 years of age. Open fractures constituted 9.8% of the series and were mainly due to traffic accidents in town dwellers, the most vulnerable bones were those of the leg and foot. Pathological fractures accounted for 2.2% and were due to bone cysts and osteogenesis imperfecta. The problem of child safety and the preventive measures need to be more stressed. 相似文献
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T Coniglione 《Canadian Metallurgical Quarterly》1998,91(8):446-448
It is a common opinion that general surgery is the first step for whoever approaches a surgical discipline, and that whoever practices training in general surgery should learn the rudiments of each surgical branch. The role of microsurgery in the training of the general surgeon has not been well-established. Clinical applications of microsurgery in general surgery are few and are rarely required, and have been connected strictly to restricted indications. However, we think that microsurgery could be very useful to the general surgeon because it allows the execution of experimental research on rats, the only possibility permitted by law. In these studies the microsurgeon can perform many times and in a short time the same surgical operation, thus improving his skill, and easily getting familiarity with surgical instruments and sutures. 相似文献
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K Akiyama TL Gluckman A Terhakopian PM Jinadasa S Narayan S Singaswamy B Massey RJ Bing 《Canadian Metallurgical Quarterly》1997,29(6):733-743
We report the appearance of apoptotic cells in experimental myocardial infarction (rabbit heart) in in situ and in vitro preparations. Apoptosis was recognized by intravital staining with Hoechst 33342 (Ho342), by nick-end labeling (TUNEL) and by DNA laddering. A steady rise in the relative number of apoptotic cardiomyocytes (apoptotic index) was noted in in situ preparations. Apoptosis was first noted 6 h after the onset of ischemia with its highest value occurring after 72 h. Apoptotic nuclei were absent in remote areas of the left and right ventricles. Apoptotic nuclei within the infarcted area showed diminished intensity of Ho342 fluorescence. Three days after ischemia, a border zone adjacent to the infarcted area consisting of apoptotic macrophages was recognized. A novel finding was the appearance of apoptotic cardiomyocytes in the isolated perfused ischemic heart. Occurring as early as 50 min after the onset of ischemia, a high apoptotic index was present adjacent to the ligature placed around the coronary artery. This observation provides the opportunity to selectively examine factors leading to apoptosis in the ischemic heart under controlled experimental conditions. 相似文献