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1.
PubMed数据库中我国论文撤销原因及学术影响力分析   总被引:1,自引:0,他引:1  
【目的】 分析PubMed数据库中因不同原因撤销的我国论文的文献计量学特征以及净化效果。【方法】 收集2005—2014年PubMed因不同原因而撤销的我国学术论文的地区、期刊分布情况;分析撤销论文数量随时间的变化趋势以及撤销论文的撤销时滞和净化效果。【结果】 共检索到撤销的中国论文370篇,撤销原因中,剽窃类型最多,错误次之,其次为重复发表、学术道德问题。因错误和学术不端撤销的论文数量逐年增长。湖北、上海、北京、山东、江苏、浙江、广东、台湾、黑龙江、陕西、重庆显示度比较高。期刊的分布比较分散,表现规律不明显。各种类型净化时间成本均衡。除其他类型外,各种类型论文撤销后学术净化效果显著。【结论】 揭示了我国生物医学类论文撤销的主要原因及不同原因撤销论文的净化效果。建议编辑、期刊、数据库出版商应当规范和完善撤销声明和撤销原因的标注,避免引用撤销后的论文,共同净化学术环境。  相似文献   
2.
This paper describes the NiiMi process designed to treat landscape water. The main aim of the research was to investigate the feasibility of NiiMi for removing organic and nutriment materials from landscape water. During the batch-scale NiiMi operation, the removal rates of color ranged from 66.7%o-80% , of turbidity from 31.7%-89.3%o, of chemical oxygen demand (COD) from 7%-36.5%, of total phosphor (TP) from 43%-84.2%, of soluble phosphate from 42.9%-100%, of total nitrogen (TN) from 4.2%-46.7%, and of NH4^+-N from 39.3%-100% at the hydraulic loading of 0.2 m^3/(m^2·d). Results showed that the removal efficiencies of COD, TP, soluble phosphate and TN decreased with the decline in the temperature. The NiiMi process had a strong shock loading ability for the removal of the organics, turbidity, TP, soluble phosphate, TN and NH4^+-N. Three sodium chloride tracer studies were conducted, labeled as TS 1, TS2, and TS3, respectively. The mean hydraulic retention times (mean HRTs) were 31 h and 28 h for TSI and TS2, respectively, indicating the occurrence of a dead zone volume of 12% and 20% for TS 1 and TS2, respectively. TS 1 and TS2 displayed the occurrence of short-circuiting in the NiiMi system. The comparison results between TS1 and TS2 were further confirmed in the values obtained for some indicators, such as volumetric efficiency (e), short-circuiting (S), hydraulic efficiency (2) and number of continuously stirred tank reactors (N).  相似文献   
3.
拉萨河流域甲玛湿地水质净化功能研究   总被引:1,自引:0,他引:1  
布多  李明礼  德吉  许祖银  旦增  刘勇 《资源科学》2010,32(9):1650-1656
水质净化功能是湿地的一个重要生态功能之一,本文以西藏拉萨河流域甲玛湿地作为研究对象,对湿地水的色度、浊度、pH值、水温、溶解氧和20种相对重要的金属元素的含量进行了初步研究。发现,西藏甲玛湿地水的pH值、DO值分别为7.40、8.07mg/L;甲玛湿地水中金属元素含量普遍较低,并且水中各种金属元素的含量也差异较大,它们的含量序列为:CaAsMgNaKFeAlCuMnZnMoNiCrPbSbCoCdSeHgBe。通过对进水和出水水质的比较发现甲玛湿地对色度、浊度和金属元素的去除效果比较明显。对色度、浊度的去除率分别达到了达到了65.1%、63.8%,对不同金属元素的去除效果不同,金属元素的去除率从高到低的顺序为:BeAlPbCuCdFeSeCoMnNiAsZn。其中对铍、铝、铅、铜、镉和铁六种金属元素的去除效果最明显,它们的去除率分别达到了73.33%、70.38%、67.95%、67.08%、66.30%、65.50%,对总硬度(Ca、Mg)、Na、Hg、K、Cr、Sb等几种金属元素的去除效率很差、几乎不能被去除。  相似文献   
4.
Seventeen healthy adults exercised for 30 min (70% V O 2max ), at different times of the day and night throughout a 24 h period. The effect on the phase of core temperature rhythm was assessed by comparing the rhythms on the day immediately before and immediately after the day of exercise with the participants living normally on these 2 days. Assessments were made upon data that had been corrected for the thermogenic effects of sleep and activity. When exercise was performed in the period between 4 h before and 1 h after the temperature minimum, there was a phase delay of 1.03 - 0.78 h (mean - s ; n = 6); when performed between 3 and 8 h after the temperature minimum, there was a phase advance of 1.07 - 1.23 h ( n = 9). Both means were significantly different from zero (Student's one-sample t -tests: P ? 0.05). Performed at other times, exercise had no significant effect on the phase of the temperature rhythm. The phase changes were not significantly different from those previously observed by us in sedentary individuals exposed to domestic lighting. We conclude that the amount of physical activity has very little effect on the body clock.  相似文献   
5.
摘要:文章简要介绍了目前β-甲基萘分离精制的工艺研究现状,在此基础上经过多次实验,提出一种新的β-甲基蔡生产方法,即把工业甲基萘经两次酸洗后,一次精馏就得到含量大于96%的产品,收率可达60%,高于国内现有生产水平。  相似文献   
6.
曾志红 《宜春学院学报》2007,29(2):148-149,176
饮用水污染问题日趋严重,本文根据莆田市环保局的统计数据,分析了饮用水污染的原因,提出了利用生物技术对饮用水源进行保护和水质净化,以保障饮用水安全.  相似文献   
7.
以构建的表达拟南芥热激因子HsfA1a C端氨基酸331到氨基酸486(简称△HsfA1a)的大肠杆菌Ecoli M15为材料,用异丙基硫代-β-D-半乳糖苷(IVFG)诱导表达△HsfA1a,再通过Ni—NTA—Agarose亲和层析纯化表达的△HsfA1a,通过SDS—PAGE电泳分析表达蛋白和纯化蛋白,获得了表达纯化的△HsfA1a.  相似文献   
8.
北五味子果实中多糖的提取与纯化研究   总被引:30,自引:0,他引:30  
经提取、醇析、Savage法脱蛋白、脱脂、脱色、DEAE纤维素柱色谱等步骤,从北五味子中分离出两种多糖组分,并经紫外光谱、红外光谱确证纯度.北五味子中粗多糖含量6.1%,三次提取率分别为:55.6%,38.5%,4.6%,Savage法脱蛋白粗多糖损失率为7.2%,北五味子中两种纯多糖含量分别为0.387%,0.061%.  相似文献   
9.
用粗尼龙筛分离混合虫株 ,置 2 .5 %重铬酸钾溶液 ,2 8℃~ 2 9℃恒温箱中培养 ,孢子化后接种鸡 ,7日后扑杀取小肠前段 ,经磨碎、孢子化、单卵囊鉴定、回归试验。第二次试验纯化后的孢子化卵囊 ,用 2 %琼脂溶液 ( 60~ 70℃ )包埋卵囊 ,待完全凝固后 ,在高倍显微镜下观察 ,用分离针、刀片分割琼脂球虫块至单个卵囊 ,再次接种鸡进行回归试验。直到纯化成堆型艾美耳球虫  相似文献   
10.
INTRODUCTION Aqueous two-phase system (ATPS) is widely used in biochemistry and biotechnology for purifica- tion of proteins (Diamond and Hsu, 1992; Balasubramaniam et al., 2003), enzymes (Pan et al., 2001; Bim and Franco, 2000), amino acids (Li et al., 2002), antibiotics (Yang et al., 1994; Guan et al., 1994), nucleic acids (Ohlsson et al., 1978; Kimura, 2000), aroma compounds (Marco et al., 2000) and lactic acid (Planas et al., 1998). ATPS is mainly composed of two-incompatible p…  相似文献   
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