Purification of Ammonium Perrhenate Solutions from Potassium by Ion Exchange

The article presents a detailed study on the purification of crude ammonium perrhenate solutions from potassium using KU-2 Russian cation exchange resin. Some of the vital parameters such as effect of various forms of salts linked with cation exchange resins (Н⁺, NН₄⁺), effect of flow rate of the solution (1, 2, 5 specific volume per hour), and the influence of potassium concentration (10, 20, 40, 60, and 100 mg/L) on its extraction from the solution have been studied under varying experimental conditions. A high-purity salt was obtained from preliminary purified crude salt solutions by evaporation and subsequent crystallization under optimum conditions: solution was evaporated five times and subsequent cooling to 20°С. The method was tested on a pilot scale using a batch of commercial crude ammonium perrhenate salt. Following the pilot scale test, the method has been successfully applied at one of the biggest enterprises of Kazakhstan, i.e., Zhezkazganredmet.     

盐雾腐蚀对HRB400E抗震钢筋低周疲劳和力学性能的影响

摘要：采用质量分数为5%的NaCl溶液在盐雾腐蚀箱进行30~90d加速腐蚀试验,研究了盐雾腐蚀对HRB400E钢筋低周疲劳行为和拉伸性能的影响。然后采用轴向位移控制模拟地震载荷对腐蚀钢筋开展了低周疲劳和拉伸试验,获得循环响应特征曲线和应变 寿命曲线。结合SEM断口形貌观察,分析钢筋的低周疲劳断裂机制。结果表明：盐雾腐蚀对钢筋的质量和尺寸有明显影响,钢筋表面产生腐蚀坑;钢筋的力学性能随腐蚀时间增加而降低,腐蚀90d的断裂伸长率下降率达461%,屈服强度在腐蚀30d以后可能就不再满足标准要求;腐蚀明显削弱了钢筋的抗循环载荷性能,导致低周疲劳寿命下降;腐蚀会减小钢筋的裂纹扩展区面积并加速裂纹扩展。     

Differences in isoproterenol-stimulated melatonin production by perifused rat pineal glands: time dependent effects and role of enantiomeric forms

The perifusion of rat pineal glands removed at different times of the light-dark cycle showed a greater beta adrenergic-stimulated production of melatonin in glands obtained at the beginning of either the light or the dark stage. The effect of isoproterenol was found dependent upon its enantiomeric forms (-, +/-, +). The relative order of potency was (-) > (+/-) > (+) enantiomer. These results show that the response of pineal beta-adrenergic receptors to isoproterenol is stereospecific and circadian stage dependent.     

盐岩巴西劈裂损伤愈合特性实验研究

盐岩的损伤愈合特性对地下盐穴储库的长期密闭性具有重要影响。为了探究损伤盐岩的愈合特性,设计了巴西劈裂损伤盐岩的自愈合实验。在无应力条件下,让巴西劈裂损伤盐岩在不同湿度条件下愈合120 d,通过实验过程中试样渗透率的变化定量判断损伤盐岩愈合程度,探究了损伤盐岩在不同湿度和恢复时间条件下的愈合效果;同时,通过扫描电子显微镜对损伤盐岩愈合后的细观形貌进行了观察,探讨了盐岩损伤愈合的细观机制。本实验中,利用实验前后渗透率的变化作为损伤盐岩愈合的表征手段,有效避免了以往研究中利用试样强度和弹性模量作为损伤愈合表征手段时因应变硬化导致的结果不可靠的情况。实验结果表明,在无应力作用条件下,在无外界水分供给环境中试件经过120 d后仍然没有发现愈合,证明水分是损伤愈合的必要条件。研究表明,时间和湿度对盐岩的损伤愈合具有重要影响,盐岩的损伤愈合效果在实验范围内随着时间的增长和湿度的增大而增强,但增强速度呈指数降低,意味着过大的湿度和过长的时间难以有效提高盐岩损伤愈合效果。      

对不同环境的2D70铝合金低周疲劳性能研究

对2D70铝合金在试验室空气、湿空气、盐雾及盐雾+SO四种环境下进行低周疲劳试验,对比四种环境下的循环σ-ε2曲线及应变-寿命曲线,得出结论:相同应变下,2D70铝合金随腐蚀环境增强,循环应力降低;相同应变下,2D70铝合金在盐雾及盐雾+SO两种环境下低周疲劳寿命相近,并且随着腐蚀环境的增强,低周疲劳寿命降低;腐蚀环境越强,材料疲劳损2伤程度越大。研究结果为预测飞机不同环境的低周疲劳寿命提供了参考,对飞机腐蚀防护及耐久性设计具有重要意义。     

The effect of ethylenediamine on the ion exchange behaviour of cobalt,nickel, copper,cadmium and zinc I. Equilibrium experiments

The ion exchange behaviour of Co, Ni, Cu, Cd and Zn on a carboxylic acid type and a sulphonic acid type cation exchanger has been studied to determine whether selective recovery of these metals from complex solutions could be achieved. Batch equilibration tests carried out on each metal in its aquo-ionic form, using Na- and H-form cation exchangers, showed similar behaviour of the metals towards both resins.Increasing concentration of ethylenediamine gave rise to considerable affinity differences for the metals with the weak acid resin. Although the experimental results showed that the addition of ethylenediamine reduces the absolute amounts of metals taken up by the carboxylic resin in the Na-form, the pronounced differences in affinity result in an increased selectivity according to the order: Ni < Zn < Cd < Cu < Co.     

Flow Depletion of Semipervious Streams Due to Pumping

Expressions for the rate and volume of flow depletion of semipervious streams due to pumping are presented in computationally simple forms. Analytical expressions have been proposed to take into account both partial penetration and semipervious bed and banks of the stream. Graphs suitable for engineering applications are presented for siting wells, and the effect of an intermittent pumping cycle on the rate and volume of stream flow depletion has also been discussed. The exclusive volume of flow depletion during a cycle is shown to vary with the selection of the end of the cycle.     

The regulation of 3-hydroxy-3-methylglutaryl coenzyme A reductase in the isolated perfused rat liver

The effect of perfusion of an isolated rat liver on hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase was studied. In liver removed during the basal period of the diurnal cycle of enzyme activity, a 227 +/- 41% increase in enzyme activity occurred after 3 h of a plasma-free perfusion. This could be prevented by the addition of cycloheximide or pure cholesterol (dispersed with lecithin) to the perfusate. In contrast, the continuous addition of taurocholate or taurochenodeoxycholate, alone or in combination, at a variety of rates did not prevent the increase in enzyme activity. The added bile salts were efficiently extracted from the perfusate and excreted in the bile. The addition of these bile salts to a cholesterol-enriched perfusate did not alter the effect obtained with cholesterol alone. If the perfusate contained whole serum, the increase induced by perfusion in the basal period was smaller (88 +/- 27%) than with plasma-free perfusate. Again, the major bile salts of the rat failed to prevent the increase in enzyme activity induced by liver perfusion. If livers were removed and perfused at the height of the diurnal cycle of enzyme activity, the enzyme activity remained high (2 +/- 10% increase) rather than decreasing, as occurs in vivo. If cholesterol was added to these perfusions, a 52 +/- 4% decrease was induced. Bile salt addition induced no decrease. From the results it is concluded that the major bile salts are not direct regulators of hepatic cholesterol synthesis, but pure cholesterol, in the absence of bile salt or lipoprotein, is able to initiate the mechanism that represses hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase.     

Blood flow lipid transport from viewpoint of protein biochemistry

In accordance with the principles of protein biochemistry, apolipoprotein is the only protein which: 1) forms a protein-lipid complex (PLC) mainly from one class of lipids; 2) determines its functional role; 3) causes dyslipidemia in the genetic destruction of apoproteins or their quantitative ratio. Blood flow lipid transport is based on the functional specificity of their apoproteins; each apoprotein forms a functionally independent PLC; each PLC is formed from one class of lipids; each PLC has one protein-vector; each protein-vector interacts only with receptor. The basis of a united cycle functioning in lipid transport is the difference of primary apoprotein structure. Cholesterol performs an auxiliary function in triglyceride transport by providing circulation in the functional cycle. Lipid transport in blood flow is based, first, on the principles of protein biochemistry and, second, on those of lipidology.     

LiCl-KCl熔盐中电解还原钛铁矿的研究

在LiCl-KCl熔盐中,采用熔盐电解法还原钛铁矿,研究了电解时间、槽电压及电解温度对还原钛铁矿的影响,探讨了在熔盐中钛铁矿电解脱氧的机理。结果表明,钛铁矿还原优先生成铁,钛氧化物由高价到低价逐步还原,而未得到金属钛及其合金,说明在LiCl-KCl熔盐中,TiO的脱氧还原是钛铁矿熔盐电解生成金属钛及其合金的反应限制性步骤。     

降低软水站盐耗水耗的措施

为降低软水站系统的盐耗及水耗,对软化器进水流量,再生液浓度,再生操作、正洗反洗操作等进行了优化。软化器进水流量以110m3/h为宜;通过改进再生液注入方式及采用1.7m—1.25t的液位—投盐量,可保证再生液浓度;同时设置了预正洗并优化了反冲洗操作。改进后,软化器使用周期延长41.1%,周期软水产量增加38.9%,软水站盐耗减少15.8t/月,水耗减少6125t/月。     

The effect of chromatographically pure sample of adenosine 5''-tetraphosphate on sheep and rabbit blood platelets

1. The commercially available trisodium salt of adenosine 5'-tetraphosphate (ATetraP) (Sigma) was found to be contaminated with ATP, ADP and AMP, and therefore unsuitable for use in platelet studies. 2. The more stable barium salt of ATetraP was converted to the ammonium salt and found to be chromatographically homogeneous. This sample was tested for its influence on sheep blood platelets in citrated-rich plasma by the photometric method. 3. The ammonium salt of ATetraP (5-105 mumol.1(-1)) induced platelet aggregation which showed no tendency towards disaggregation. 4. The log dose-response lines for ATetraP and for adenosine diphosphate were parallel. On a molar basis, the tetraphosphate and only 1.5% of the aggregating activity of ADP. 5. The initial rate of aggregation induced by the tetraphosphate was inhibited by adenosine 5'-monophosphate analogues which are selective ADP-antagonists. These compounds also dispersed aggregates produced by ATetraP. 6. Platelets made refractory to ADP were also refractory to ATetraP. 7. Like ADP, ATetraP induced the change in shape of rabbit platelets and in this respect had only 3.4% the activity of ADP. 8. It is concluded that ATetraP per se can induced platelet aggregation and platelet shape change, and appears to exert its effect at the same site on the platelet surface as does ADP.     

Mechanisms of inhibition of aldehyde dehydrogenase by nitroxyl, the active metabolite of the alcohol deterrent agent cyanamide

Nitroxyl, produced in the bioactivation of the alcohol deterrent agent cyanamide, is a potent inhibitor of aldehyde dehydrogenase (AIDH); however, the mechanism of inhibition of AlDH by nitroxyl has not been described previously. Nitroxyl is also generated from Angeli's salt (Na2N2O3) at physiological pH, and, indeed, Angeli's salt inhibited yeast AlDH in a time- and concentration-dependent manner, with IC50 values under anaerobic conditions with and without NAD+ of 1.3 and 1.8 microM, respectively. Benzaldehyde, a substrate for AlDH, competitively blocked the inhibition of this enzyme by nitroxyl in the presence of NAD+, but not in its absence, in accord with the ordered mechanism of this reaction. The sulfhydryl reagents dithiothreitol (5 mM) and reduced glutathione (10 mM) completely blocked the inhibition of AlDH by Angeli's salt. These thiols were also able to partially restore activity to the nitroxyl-inhibited enzyme, the extent of reactivation being dependent on the pH at which the inactivation occurred. This pH dependency indicates the formation of two inhibited forms of the enzyme, with an irreversible form predominant at pH 7.5 and below, and a reversible form predominant at pH 8.5 and above. The reversible form of the inhibited enzyme is postulated to be an intra-subunit disulfide, while the irreversible form is postulated to be a sulfinamide. Both forms of the inhibited enzyme are derived via a common N-hydroxysulfenamide intermediate produced by the addition of nitroxyl to active site cysteine thiol(s).     

拜耳法生产氧化铝熔盐加热系统开停车模式优化及回盐液位计算

导出了管道化溶出熔盐加热系统熔盐体积的计算公式、不同温度下熔盐密度的计算公式、盐槽液位计算迭代式,给出了回盐温度对盐槽液位的定量影响,提出了一系列预防熔盐堵管的措施。改进后的开停车模式,相对经济、可靠。     

Regional Distribution and Prospects of Potash in China

China was formed by amalgamation of several small continental blocks (cratons), micro,blocks and orogenic belts in different paleoclimatic settings. It may be correlated with other continental blocks but has its own specific characteristics; therefore the tectonic environments of China's marine and continental saline basins and salt, and potash, forming environment have some specific characteristics: multiple phases of salt formation, difference in salt, forming ages, migration and concentration of salt forming processes and diversity of component materials, as well as small sizes of marine saline basins and great changes of saline basins in the late stage and occurrence of abundant liquid mineral resources. The nature of the tectonic basement exerted a key controlling effect on the formation of potash basins. The stable tectonic region was favorable for potash concentration in a quasi, stable region, and quasi, and the quasi-stable region was favorable for salt concentration and potash formation in a local stable tectonic region. Most China's major ancient saline basins occur in "quasi, cratons (continental block)"; especially all the marine saline basins occur in continental blocks with the Precambrian basement. These regions are the key ones for potash search. Most relatively large, scale soluble salt deposits are developed in relatively stable continental nuclei. According to the characteristics of the tectonic domains where China's salt, forming basins are located, the North China Yangtze and Tarim, Qaidam salt minerogenetic domains and the nortbern Qiangtang, western Yunnan salt minerogenetic belt may be distinguished. Their salt and potash prospects wiU be discussed separately.     

离子型稀土矿山集液沟区域耐盐异养硝化细菌的筛选及其脱氮特征

为筛选处理高盐含氨氮矿冶废水的耐盐微生物,从赣南离子型稀土矿山集液沟区域采集样品,利用选择性培养基富集培养分离耐盐异养硝化细菌,并考察碳源、pH、盐度等因素对其脱氮性能的影响.结果表明,分离得到一株耐盐异养硝化细菌X1,经16S rDNA鉴定为肠杆菌属Enterobacter sp. X1,确定该菌适宜的脱氮条件为:以蔗糖作为碳源,pH值为5,盐度≤15 %.菌株X1的NH₄+-N去除率可达到60 %以上.研究结果可为高盐含氨氮矿冶废水的微生物处理提供菌株和数据参考.      

阳极气泡运动对制钠电解槽内熔盐流场的影响

模拟电解熔盐制钠过程中阳极气泡的运动,测量气泡周围流场的变化,分析阳极气泡运动对电解槽内熔盐流场的影响。利用粒子成像测速仪(PIV)测量得到平行和垂直阳极方向的流体运动,并研究液面高度及气体流量对流场的影响。