钙镁测定指示剂的研究与应用

针对配位滴定钙镁的指示剂问题进行探讨 ,以酸性铬蓝K 萘酚绿B 聚乙烯吡咯啉酮 (PVP)苦味酸体系作为测定钙镁含量指示剂 ,终点变色灵敏。应用于平炉渣、石灰石、白云石、水等样口中钙镁的测定 ,相对误差为± 0 .2 %左右 ,指示剂体系稳定 ,准确度和精密度较高     

Interactions between Polymeric Dispersants and Calcium Silicate Hydrates

To better understand the mechanism of interaction between hydrating silicate-based cements and polymeric dispersants of the type used as "superplasticizers" in modern construction concretes, two different types of polymeric dispersant were added (at concentrations of 1 and 10 g/L) during the synthesis of calcium silicate hydrate (C-S-H) via the "pozzolanic reaction" in dilute slurries of lime and reactive silica, at Ca/Si ratios in the range of 0.66–1.50. Although both polymers gave degrees of adsorption of >79% in all cases studied, no significant structural modifications of the resulting C-S-H products were observed via X-ray diffraction or ²⁹Si magic angle spinning–nuclear magnetic resonance. These results differ from recent work in which it was shown that similar types of polymer could intercalate into the interlayers of C-S-H that was made using an alternative process. It is suggested that the process by which the C-S-H is formed may have a strong influence on whether C-S-H can intercalate polymers. This observation is relevant to understanding the fate of such polymers in concrete.     

一次盐水钙法脱硝工艺研究

针对钙法脱硝工艺进行了一系列的研究试验,找出了工业化的最佳工艺条件。     

Certain Biominerals in Leaves Function as Light Scatterers

Cystoliths are amorphous calcium carbonate bodies that form in the leaves of some plant families. Cystoliths are regularly distributed in the epidermis and protrude into the photosynthetic tissue, the mesophyll. The photosynthetic pigments generate a steep light gradient in the leaf. Under most illumination regimes the outer mesophyll is light saturated, thus the photosynthetic apparatus is kinetically unable to use the excess light for photochemistry. Here we use micro‐scale modulated fluorometry to demonstrate that light scattered by the cystoliths is distributed from the photosynthetically inefficient upper tissue to the efficient, but light deprived, lower tissue. The results prove that the presence of light scatterers reduces the steep light gradient, thus enabling the leaf to use the incoming light flux more efficiently. MicroCT and electron microscopy confirm that the spatial distribution of the minerals is compatible with their optical function. During the study we encountered large calcium oxalate druses in the same anatomical location as the cystoliths. These druses proved to have similar light scattering functions as the cystoliths. This study shows that certain minerals in the leaves of different plants distribute the light flux more evenly inside the leaf.     

Live cell calcium imaging at the single ion hit facility of GSI

To study the fast intracellular calcium response after ion irradiation in living mammalian cells, a live cell calcium imaging set-up was constructed at the targeted cell irradiation facility at GSI. This work introduces the live cell calcium imaging system, shows its performance, an example of the ratio-metric calcium measurement and its application to on-line study calcium response to targeted ion irradiation in human cells.     

Wildscape: forestry,scenery and wildlife

Philip Nicholl's paper was concerned with the specialist field of how to grow two cubic metres of timber where only one grew before. Lord Dulverton, a practising forester, now places timber growing into a wider context: landscape evolution and habitats for wildlife.

Lord Dulverton is well known for his integrated view of rural land uses through his practical activities, writings, broadcasting and speeches in the House of Lords. Among his many forms of public service are his presidencies of the Timber Growers Organisation (1976–8), and the British Deer Society (1973), his chairmanship of the Forestry Committee of Great Britain (1978–80), his trusteeship of the World Wildlife Fund (UK) and his membership of the Scottish Advisory Committee to the Nature Conservancy Council (Guest Editor's introduction).     

Using lithium nitrate and pozzolanic glass powder in concrete as ASR suppressors

This investigation studies the influence of two different mineral admixtures, lithium nitrate (Li) and pozzolanic glass powder (PGP) on the expansion induced by alkali-silica reaction (ASR). Four numbers of concrete prisms were produced for each concrete mix to measure the expansion resulted from the ASR according to the test method of the BS 812-123:1999. Chemical analysis was performed using X-ray spectra. Test results confirmed that Li and PGP have significantly reduced the ASR expansion. Lower calcium to silica ratio (Ca/Si) was found in concrete mix contains (PGP) because of the high amorphous reactive silica and low calcium content in PGP compared to ordinary Portland cement CEM1. Similar components and minerals phases were obtained in different concrete mixes by using XRD.     

喷雾闪蒸干燥在重质微细碳酸钙中的应用

介绍了重质微细碳酸钙的用途及生产方法，阐述了新技术喷雾闪蒸干燥的干燥原理、特点、工艺流程、设备及重质微细碳酸钙的产品质量指标，指明喷雾闪蒸干燥传热传质效果好，干燥速度快，自动化程度高，产品质量优，发展前景广阔。     

ACR与CaCO3协同作用对PVC管材拉伸性能的研究

分别研究了CaCO3、ACR、CaCO3与ACR共混体对PVC排水管材的拉伸性能的影响。CaCO3的用量达到20％、用量5％时，当ACR管材的拉伸强度为40MPa，断裂仲长率为120％。     

In Vitro and in Vivo Characteristics of Fluorapatite-Forming Calcium Phosphate Cements

This study reports for the first time in vitro and in vivo properties of fluorapatite (FA)-forming calcium phosphate cements (CPCs). The experimental cements contained from (0 to 3.1) mass % of F, corresponding to presence of FA at levels of approximately (0 to 87) mass %. The crystallinity of the apatitic cement product increased greatly with the FA content. When implanted subcutaneously in rats, the in vivo resorption rate decreased significantly with increasing FA content. The cement with the highest FA content was not resorbed in soft tissue, making it the first known biocompatible and bioinert CPC. These bioinert CPCs might be useful for applications where slow or no resorption of the implant is required to achieve the desired clinical outcome.