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31.
Aspects of communities and events in the concentrating ponds (S.G. 1.130 to 1.214) and salt crystallizing ponds (S.G. 1.215 to 1.264) of solar saltworks pertinent to salt manufacture are described. Communities that aid salt manufacture enable continuous and efficient production of high quality salt at a saltworks' design capacity, and they provide important controls on levels of organic matter in the brine. Fluctuating salinities, high concentrations of nutrients, and petroleum products are disturbances that causeAphanothece halophytica andDunaliella salina to release excessive quantities of organic matter, and that suppress or cause death to nutrient stripping organisms. Disturbances result in decreased quality and quantity of salt and increased costs for salt harvest, washing, and pond upkeep. Organic matter can be controlled by management techniques that keep nutrient stripping communities at proper levels and maintain a narrow and unchanging range of salinities in each pond, by constructing pond dikes able to withstand wind and water erosion, and by preventing spills of petroleum products in the ponds. 相似文献
32.
本文利用等温溶解度法测定了H~+,Li~+,Mg~(2+)//Cl~-—H_2O四元水盐体系在—10℃±0.1℃时的溶解度并绘制了等温相图。相图由HCl·MgCl_2·7H_2O、MgCl_2·8H_2O、HCl·6H_2O和LiCl·2H_2O四个相区构成,只有一个零变量点I:LiCl·2H_2O+MgCl_2·6H_2O+HCl·MgCl_2·7H_2O+L_(?)利用坐标变换和直线外推法,对溶解度数据进行处理后,用湿渣结线法解决了低温平衡固相较难确定的问题。 相似文献
33.
Products and mechanisms for the gas-phase reactions of NO3 radicals with CH2=CHCl, CH2=CCl2, CHCl=CCl2,cis-CHCl=CHCl andtrans-CHCl=CHCl in air have been studied. The experiments were carried out at 295±2 K and 740±5 Torr in a 480-L Teflon-coated reaction chamber and at 295±2 K and 760±5 Torr in a 250-L stainless steel reactor. NO3 was generated by the thermal dissociation of N2O5. Experiments with15NO3 and CD2CDCl have also been performed. The initially formed nitrate peroxynitrates decay into carbonyl compounds, nitrates, HCl and ClNO2. In adidtion, there are indications of nitrooxy acid chlorides being produced. The reactions with CH2=CCl2 and CHCl=CCl2 are more complex due to release of chlorine atoms which eventually lead to formation of chloroacid chlorides.A general reaction mechanism is proposed and the observed concentration-time profiles of reactants and products are simulated for each compound. The rate constants for the initial step of NO3 addition to the chloroethenes are determined as: (2.6±0.5, 9.4±0.9, 2.0±0.4 and 1.4±0.4) × 10–16 cm3 molecule–1 s–1 for CH2=CHCl, CH2=CCl2, CHCl=CCl2 andcis-CHCl=CHCl, respectively. 相似文献
34.
We report on the use of X-ray diffractometry under controlled conditions of temperature and relative humidity (RH-XRD) for
the investigation of NaCl deliquescence in the pore space of glass filter frits, which were used as model substrates. The
study confirms that RH-XRD is an appropriate experimental technique for the in situ observation of phase transformation in
porous materials. It is used for an investigation of both the deliquescence kinetics and the deliquescence humidity within
pores of different median pore diameter. Several major influences affecting deliquescence rates in the pore space close to
the surface of a porous material are discussed. It appears that quite short-term variation of ambient relative humidity, e.g.,
typical daily fluctuations, might induce damaging deliquescence–crystallization cycles within the pore space of building materials.
In agreement with theoretical considerations it was found that confinement of NaCl crystals in pores with median diameters
in the range 1.4–70 μm does not affect the deliquescence humidity of the salt. 相似文献
35.
将碳酸钙试样用盐酸溶解后,在0.6mol/L的盐酸介质中,用KI-MIBK萃取试样中微量的铅和镉,有机相用原子吸收分光光度法测定。该方法测定铅的相对标准偏差为2.38%-6.31%,回收率为96.5%-97.0%;测定镉的相对标准偏差为4.50%-5.52%,回收率为96%-102.8%。结果可靠,具有灵敏、准确、快速、选择性好等优点。适用于碳酸钙中铅、镉的测定。 相似文献
36.
土壤中钙形态的连续浸提方法 总被引:4,自引:0,他引:4
通过改进的连续浸提技术,把土壤钙的赋存形态划分为5个类型:水溶态、交换态、酸溶态、有机结合态及残渣态,用原子吸收光谱法测定各形态钙含量及总钙量,各形态钙的加和值与测得的总钙量基本相符,且各形态钙8次浸提的相对标准偏差基本在10%以内。探讨了改进的连续浸提方法提取条件(包括浸提剂、水土比、提取时间、离心速率及离心时间等)对提取效果的影响。结果表明,土壤中各形态钙可以满足生态地球化学土壤样品评价需要。 相似文献
37.
磷矿石中磷、钙、镁、锶、氟测定方法评述 总被引:2,自引:0,他引:2
本文系统分析了磷矿石高含量磷、钙、镁、锶、氟诸元素存在时对其测定的相互影响及其测定中存在的问题,比较全面地总结了国内分析工作者针对该问题,对诸难测元素在常规分析方法方面的工作进展。 相似文献
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