光度法测定铈的研究进展

综述了近10多年来常规光度法、催化动力学光度法、化学光度法、紫外光度法、流动注射光度法和荧光光度法测定铈的研究结果.指出在常规光度法中,碱性染料类二安替比林甲烷类显色剂灵敏度最高,但受高价离子干扰严重;化学发光光度法、流动注射光度法和催化动力学光度法测定铈的应用较少,应加强研究.     

原子吸收分光光度法与1,10-二氮杂菲分光光度法测定水中总铁的比对试验分析

原子吸收分光光度法与1，10-二氮杂菲分光光度法测定水中铁具有精密度高、准确度好的特点。用两种方法测定的已知样为0．8mg／L和1．0mg／L，经比较1，10-二氮杂菲分光光度法比原子吸收分光光度法精密度更高、准确度更好。     

钕的光度分析进展

综合了近10 a来测定钕的常规光度法、紫外光度法和催化动力学光度法.     

偶氮氯膦-mA在光度分析中的应用进展

评述了近 10年来偶氮氯膦 mA在络合光度法、催化光度法中的应用现状和进展。引文 2 4篇     

镧的光度分析进展

综述了近10多年来镧的常规光度法、紫外光度法、催化动力学光度法和化学发光法研究状况.参考文献35篇.     

二安替比林甲烷光度法测定石灰石白云石中微量二氧化钛

1 前言矿物原材料中钛的测定,一般采用过氧化氢光度法,试钛灵光度法、磺基水杨酸光度法,钽试剂光度法,变色酸光度法,二安替比林甲烷光度法等。其中二安替比林甲烷(DAPM)光度法,具有灵敏度高(ε=1.3×10~4)选择性好的特点,已广泛用于钢铁,合金及矿物原材料     

砷钒钼杂多酸—乙基紫—OP—10分光光度法测定微量砷

三苯甲烷类碱性染料——乙基紫已广泛用于萃取光度法。目前,乙基紫已用於测定微量锑、铼、铊、银、金、汞、钽、碘和磷。但萃取光度法操作手续麻烦,而且易引进误差。近年来也有人用砷钼蓝—孔雀绿水相分光光度法测定微量砷(c=7.5×10~4。我们采用胶束增溶法即以乙基紫作显色剂,OP—10作增溶剂,使砷钒钼杂多     

偶氮氯膦-MA与稀土元素显色反应的双波长分光光度法研究

在 p H =1.0的酸性介质中 ,偶氮氯膦 - MA与稀土元素形成稳定的有色络合物 ,其λmax=6 70 nm ,单波长分光光度法测得其 ε=6 .1× 10 4 ;本法采用双峰双波长光度法测得 ε=1.3× 10 5,比单波长分光光度法的灵敏度提高一倍多 ,可直接用于铁基样中痕量稀土的测定。该方法准确、快速、灵敏 ,结果满意     

铬天青S—溴化十六烷基三甲铵高灵敏分光光度法测定微量铬

铬的分光光度法测定,应用较为广泛的是二苯基碳酰二肼光度法但该法灵敏度不高(c_(540)=3.46×10~4),近年来导用胶束增溶分光光度法测定铬,其灵敏度有了较大的提高。     

三苯甲烷染料在我国光度分析和电化学分析中的应用进展

三苯甲烷类染料是目前痕量分析中一类重要的有机试剂。本文评述了 2 0世纪后 10多年间 ,三苯甲烷类染料在光度法、催化光度法和电分析法等方面在我国的应用现状及发展趋势 ,引文 12 5篇     

“全三脱”工艺流程中脱碳渣返回脱磷转炉利用

 为了在“全三脱”工艺流程中实现炉渣的高效循环利用,将[w((P2O5))]较低的热态脱碳炉终渣通过渣罐兑入脱磷炉继续发挥脱磷作用。分析结果表明,提高返回渣量及脱磷渣磷分配比均可显著降低脱磷炉石灰消耗量,当渣钢磷分配比及返回渣量控制合适时,脱磷炉可不加入石灰而使半钢磷质量分数达到目标值。对脱碳炉渣在脱磷炉冶炼中的再熔化过程进行计算分析,随着铁水中硅元素的氧化,脱碳渣碱度降低而不断熔化,逐渐发挥脱磷作用。在“全三脱”工艺流程中成功开发了转炉渣热态循环利用工艺,脱磷率提高约6%,返回脱碳渣加入量约为67.13 kg/t,石灰、轻烧白云石和萤石分别节约9.37、1.15 和2.45 kg/t,半钢温度提高约7 ℃。     

对赣南离子型稀土开发环境保护问题的几点思考

针对赣南离子型稀土开发现状，根据环境保护“十五”计划实现低劣转化的要求，提出推广高新技术，强化清洁生产管理，引入绿色环保税制等措施，解决赣南稀土开发生态环境保护问题，促进资料优势向经济优势转化，走可持续发展道路。     

金隆公司主变压器运行方式及经济运行计算

本对金隆总降压变电所2台主变压器的经济运行方式进行了计算，介绍了自投料生产以来变压器的运行方式，并对现行2台变压器的分列运行方式是否合理，经济进行了计算和验证。     

MSTP在包钢白云矿浆管道输送中的应用

MSTP在包钢为首次应用,文章紧密结合包钢白云矿浆管道输送系统工程,对矿浆管道全系统通信传输和接入的网络结构、接入方式、保护方式、可承载业务等进行了全面细致的分析,提出了建设具体实施方案,目前此项工程已实施完毕,效果很好。     

Survey of Irrigation Methods in California in 2001

Reliable information on irrigation methods is important for determining agricultural water demand trends. Therefore, a study was conducted during 2002 to collect information on irrigation methods that were used by growers to irrigate their crops in 2001. The results were compared to earlier surveys to assess trends in cropping and irrigation methods. A one-page questionnaire was developed to collect information on irrigated land by crop and irrigation methods. The questionnaire was mailed to 10,000 growers in California that were randomly selected from a list of 58,000 growers by the California Department of Food and Agriculture, excluding rice, dry-land, and livestock producers. From 1972 to 2002, the area planted has increased from 15 to 31% for orchards and from 6 to 16% for vineyards. The area planted to vegetables has remained relatively static, while that planted to field crops has declined from 67 to 42% of the irrigated area. The land irrigated by low-volume (drip and microsprinkler) irrigation has increased by about 33%, while the amount of land irrigated by surface methods has decreased by about 31%. Sprinkler usage has decreased in orchards and vineyards, but it has increased in vegetable crops.     

Difference in changes of plasma volume in two types of Goldblatt hypertension in rabbits

High plasma renin concentration (PRC) and hematocrit (Ht) were observed in hypertensive rabbits with one renal artery clipped and an intact opposite kidney (Group A), while rather low PRC and Ht in hypertensive ones with one renal artery clipped and the opposite kidney removed (Group B). Plasma volume (PV), blood volume (BV), and packed cell volume (PCV) were estimated in these two types of hypertensive rabbits, and also in sham-operated rabbits (Group C). In Group A, 4 weeks after clipping of a renal artery, PV was decreased and significant inverse correlations were observed between PV and the elevation of blood pressure and between PV and PRC. A significant correlation between PRC and the elevation of blood pressure was also found 4 and 12 weeks after the clipping. PCV was increased until 12 weeks after clipping. In Group B, PV was increased 1 and 4 weeks after clipping, then returned to the initial level. Ht was decreased 1 and 12 weeks, and PCV was decreased 12 weeks after clipping. These results would indicate that a high Ht seen in Group A was partly due to the decreased PV and partly due to the increased PCV, while, in Group B, a low Ht in early stage might be mainly due to the increased PV, but in the late stage, a decreased PCV appeared to play a role to lower Ht. PRC seems to be affected differently by PV in these two types of hypertension.     

Inhibitory effect of suramin in rat models of angiogenesis in vitro and in vivo

The aim of the present study was to test the ability of the chemotherapeutic agent suramin to inhibit angiogenesis in experimental models in vitro and in vivo. In the culture of rat aortic rings on fibronectin, suramin dose-dependently inhibited vascular cell growth, achieving the maximal effect (mean - 88% versus controls, P < 0.05) at 400 microg/ml. Image analysis showed that suramin could inhibit microvessel sprouting in fibrin from rat aortic rings as evaluated by the ratio between the cellular area and the mean gray value of the sample (sprouting index); suramin at 50 microg/ml significantly reduced the sprouting index from the control value of 0.35+/-0.04 to 0.14+/-0.02 mm2/gray level (P < 0.05). Likewise, the area occupied by cells was 19.2+/-1.8 mm2 as compared with 41.8+/-4.2 mm2 in controls (P < 0.05). In the rat model of neovascularization induced in the cornea by chemical injury, suramin at 1.6 mg/eye per day reduced the length of blood vessels (0.7+/-0.1 mm as compared with 1.5+/-0.1 mm in controls, P < 0.05). In the same model the ratio between the area of blood vessels and the total area of the cornea (area fraction score) was decreased by suramin from 0.19+/-0.02 in controls to 0.03+/-0.003 (P < 0.05). Suramin given i.p. at 30 mg/ kg per day markedly inhibited the neovascularization induced in the rat mesentery by compound 48/80 or conditioned medium from cells secreting the angiogenic protein fibroblast growth factor-3 (FGF-3). The area fraction score in control rats treated with compound 48/80 was 0.31+/-0.03, and this was reduced to 0.07+/-0.01 by suramin (P < 0.05). After i.p. administration of FGF-3 the area fraction score was reduced by suramin from 0.29+/-0.03 to 0.05+/-0.01 (P < 0.05). These results provide evidence that suramin exerts inhibitory effects on angiogenesis in both in vitro and in vivo models.     

The Role of Changes in the Annual Cycle in Earlier Onset of Climatic Spring in Northern China

Climatic changes in the onset of spring in northern China associated with changes in the annual cycle and with a recent warming trend were quantified using a recently developed adaptive data analysis tool, the Ensemble Empirical Mode Decomposition. The study was based on a homogenized daily surface air temperature (SAT) dataset for the period 1955-2003. The annual cycle here is referred to as a refined modulated annual cycle (MAC). The results show that spring at Beijing has arrived significantly earlier by about 2.98 d (10 yr)-1, of which about 1.85 d (10 yr)-1 is due to changes in the annual cycle and 1.13 d (10 yr)-1 due to the long-term warming trend. Variations in the MAC component explain about 92.5% of the total variance in the Beijing daily SAT series and could cause as much as a 20-day shift in the onset of spring from one year to another. The onset of spring has been advancing all over northern China, but more significant in the east than in the west part of the region. These differences are somehow unexplainable by the zonal pattern of the warming trend over the whole region, but can be explained by opposite changes in the spring phase of the MAC, i.e. advancing in the east while delaying in the west. In the east of northern China, the change in the spring phase of MAC explains 40%-60% of the spring onset trend and is attributable to a weakening Asian winter monsoon. The average sea level pressure in Siberia (55°-80°N, 50°-110°E), an index of the strength of the winter monsoon, could serve as a potential short-term predictor for the onset of spring in the east of northern China.     

Stimulation of ileal transport of calcium by sorbitol in in situ perfused loop in rats

OBJECTIVES: The aim of this study was to study the effect of sorbitol on sodium, water and calcium fluxes in rat ileum in situ perfused loop. METHODS: Net water, sodium and calcium fluxes, and one-way calcium fluxes were measured in situ in a perfused rat ileal loop in the presence of varying concentrations of sorbital. RESULTS: High concentrations of sorbitol in perfused ileal solution induced a decrease of sodium and water fluxes and a concomitant increase of lumen to mucosa calcium flux associated with an increase of net calcium flux, using a solution containing either 8.0 or 1.25 mM calcium. These effects were independent of absolute initial values of water and sodium fluxes. They were observed in the presence of 25 mM glucose, 10 mM theophyllin or after treatment of rats with dexamethasone. CONCLUSION: These effects of sorbitol on calcium flux are not compatible with a stimulation of paracellular pathway. By contrast, they can be explained by a stimulation of transcellular calcium pathway in ileum associated with the hyperpolarisation of the cells induced by the decrease of luminal sodium concentration necessary in the presence of sorbitol to maintain unchanged osmolarity of perfusate.     

Role of cholesterol in the modulation of interdigitation in phosphatidylethanols

Phosphatidylethanol (Peth) is formed in biological membranes when ethanol replaces water in the transphosphatidylation reaction catalyzed by phospholipase D. This charged lipid accumulates in the presence of ethanol, and it has unusual properties that can influence membrane structure and function. We have previously shown that dimyristoylphosphatidylethanol (DMPeth) and dipalmitoylphosphatidylethanol (DPPeth) form the interdigitated gel phase in the presence of Tris-HCl [O.P. Bondar, E.S. Rowe, Biophys. J., 71 (1996) 1440-1449]. In the present investigation, differential scanning calorimetry (DSC) and fluorescence have been used to investigate the effect of cholesterol on the phase behavior of DPPeth and DMPeth. Our results show that cholesterol prevents the formation of the interdigitated phase in the presence of Tris-HCl, and that ethanol counters this influence and restores the ability of these lipids to interdigitate. Pyrene-PC fluorescence probe was used in this investigation and gave results that were in agreement with the conclusions based on the DSC study.