光卤石矿类型对冷分解-浮选法生产氯化钾工艺的影响

光卤石冷分解-浮选法生产氯化钾工艺以正常光卤石(MgCl2/KCl=1.400～1.800,KCl/NaCl≈1.00)完全分解为最理想,但在实际生产中,因受卤水组成和盐田工艺控制的影响,已出现了各种非常规的盐田光卤石.本文通过计算比较说明:高钠光卤石分解回收率最高,单位氯化钾产量分解耗水量相对较少,分解产物质量一般,与高镁光卤石、高镁高钠低钾光卤石相比,经济效益最好.     

Search for a wetting layer in thin film growth of para-hexaphenyl on KCl(001)

The non-existence of a strongly bound wetting layer for the system para-hexaphenyl (6P)-KCl(001) was verified by thermal desorption spectroscopy (TDS) and X-ray photoelectron spectroscopy (XPS). The 6P films were grown by physical vapour deposition under ultrahigh vacuum conditions at 400 K. TDS showed just a single desorption peak even down to a coverage of 0.1 nm mean film thickness. The heat of evaporation for 6P was determined to 2.3 eV. From the change of the XPS K2p substrate signal as a function of the mean film thickness one can conclude that a strong de-wetting exists at the very beginning of the 6P layer growth at 400 K. Additional investigations with atomic force microscopy reveal that at this initial stage the film grows in a form of needle like islands with a high aspect ratio and subsequently terraced mounds of 6P are formed. No dissociation of 6P on KCl was observed.     

Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

An aqueous gel electrolyte has for the first time been successfully applied to the MnO₂·nH₂O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H₂O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10⁻¹ S cm⁻¹. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg).     

我国海水钾资源开发利用技术现状与发展趋势

在我国海水钾资源的开发是人们广泛关注的问题。本文论述了国内苦卤提钾和海水提钾的工艺路线和技术经济指标 ,分析了各种工艺的特色、优缺点和发展现状 ,并提出了发展我国海水钾资源利用技术的建议     

Phase Characterizations and Photocatalytic Applications of CuO-K2M04013 Composites

A series of CuO-K₂Mo₄O₁₃composite materials have been prepared by mixing appropriates quantities,in solid state,of CuO and pure K₂Mo₄O₁₃ according to the molar ratios CuO/K₂Mo₄O₁₃ = 0.05,0.1,0.2,0.5,and 1.The prepared samples were characterized using techniques such as X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FT-IR）,differential thermal analysis（DTA）,nitrogen adsorption measurements,and UV spectroscopy.According to XRD results,the phase composition of the CuO-K₂Mo₄O₁₃ systems has significantly changed by increasing the molar ratio CuO/K₂Mo₄O₁₃ where new phases,identified as K₂Mo₃O₁₀ and CuMoO₄,have been detected.The formation of these new phases has been tracked through FT-IR and DTA measurements.The nitrogen adsorption-desorption measurements also reveal a change in the pore type of me studied materials due to the presence of these new phases.The photocatalytic activities of K₂Mo₄O₁₃ and CuO-K₂Mo₄O₁₃ composites were studied by means of monitoring the ability of these materials to the degradation,under UV irradiation,of methyl red in liquid media.It was found that the phase composition of the used samples significantly controls their photocatalytic activities.     

Effects of the central potassium ions on the G-quadruplex and stabilizer binding

Human telomeres undertake the structure of intra-molecular parallel G-quadruplex in the presence of K⁺ in eukaryotic cell. Stabilization of the telomere G-quadruplex represents a potential strategy to prevent telomere lengthening by telomerase in cancer therapy. Current work demonstrates that the binding of central K⁺ with the parallel G-quadruplex is a coordinated water directed step-wise process. The K⁺ above the top G-tetrad is prone to leak into environment and the 5′-adenine quickly flips over the top G-tetrad, leading to the bottom gate of G-tetrads as the only viable pathway of K⁺ binding. Present molecular dynamics studies on the two most potent stabilizers RHPS4 and BRACO-19 reveal that the central K⁺ has little influence on the binding conformations of the bound stabilizers. But without the central K⁺, either RHPS4 or BRACO-19 cannot stabilize the structure of G-quadruplex. The binding strength of stabilizers evaluated by the MM-PBSA method follows the order of BRACO-19> RHPS4, which agrees with the experimental results. The difference in binding affinities between RHPS4 and BRACO-19 is probably related to the ability to form intramolecular hydrogen bonds and favorable van del Waals interactions with G-quadruplex. In the models that have one central K⁺ located at the upper/lower binding site, the corresponding top/bottom stacked stabilizers show more favorable binding affinities, indicating the apparent promoting effect of central K⁺ on the stabilizer binding. Our findings provide further insights into the regulatory effect of K⁺ on the G-quadruplex targeted binding, which is meaningful to the development of G-quadruplex stabilizers.     

Thermodynamic evaluation of new absorbent mixtures of lithium bromide and organic salts for absorption refrigeration machines

Mixtures of lithium bromide and organic salts of sodium and potassium (formate, acetate and lactate) have been evaluated as alternative absorbents for absorption refrigeration machines. The main objective is to overpass the limitations of lithium bromide and improve the characteristics and the efficiency of the refrigeration cycle. In order to select the mixture that presents better properties for its employment in absorption refrigeration cycles, a thermodynamic analysis have been done. Density, viscosity, enthalpies of dilution, solubility and vapour pressure data of the proposed mixtures have been measured. A simulation program has been developed to evaluate temperatures, heats exchanged in the different sections and the efficiency of the cycle.     

Effects of food preservatives on Alternaria alternata growth and tenuazonic acid production

The effects of different organic acids on Alternaria alternata growth and tenuazonic acid production (TeA) were evaluated. Both TeA pure toxin solution and TeA production in solid medium were considered. Sodium benzoate, potassium sorbate and sodium propionate, all preservatives commonly used by food industry in Argentina, were tested. TeA was stable as pure toxin solution when was treated with the salts of organic acids used. A differential effect was observed when the preservatives were evaluated in relation to A. alternata growth and TeA production in solid medium. L evels above 10mg/kg of sodium benzoate and potassium sorbate produced a total inhibition of fungal development and toxin biosynthesis. Sodium propionate produced a 59% decrease in A. alternata growth and total inhibition of TeA production only at the highest concentration of preservatives used.     

硫酸钾钻井液体系的室内评价与应用

受加拿大皇朝公司在宋芳屯油田州13区块采用硫酸钾钻井液成功进行油层保护的启发,在室内优选出的硫酸钾钻井液体系的基本配方为:5%膨润土 0.4%Na2CO3 5.0%K2SO4 1000mg/LDCL 200mg/LDesco 100mg/LAlcome 500mg/LSAP 1000mg/LLT 1000mg/LKEL,K 含量为50000mg/L时,钻井液具有合适的粘度、切力和滤失量,页岩滚动回收率大于85%,岩心静态膨胀率小于2%,岩心伤害率小于20%。其保护油气层的机理为:K 抑制粘土水化膨胀的能力、油层保护剂的吸附能力、K 与油层保护剂的协同作用。     

界面反应对K_2O·STiO_2(W)/ZL109复合材料高温强度的影响

K_2O·8TiO_2(W)/ZL109复合材料在500℃下热暴露20h后高温强度最高,热暴露时间超过20h,随着热暴露时间的延长,其高温强度逐渐下降。界面反应是导致其高温强度下降的原因。