伽马料位计在预热器旋风筒上的应用及安装调试经验

介绍伽马料位计的原理,在预热器旋风筒的安装经验和注意事项,以及在生产中出现的问题和解决方案。     

轴流式止回阀在LNG接收站中的应用

简述了轴流式止回阀的结构、性能特点,根据LNG接收站的功能定位和各管路系统特点提出了轴流式止回阀的选择原则,以某工程案例为依据提出了LNG接收站应用于轴流式止回阀的位置组合,简述了应用于LNG接收站的轴流式止回阀的性能要求和国内外生产现状,提出了国产化的必要性。     

EVAPORATION FROM SINGLE DROPLETS IMPINGING ON HEATED SURFACES

Thermal behaviour of liquid droplets on a heated solid surface was studied experimentally using metallic/nonmetallic solids of different characteristics and variety of liquids, from distilled water through pure organic solvents and binary mixtures to solutions, suspensions and emulsions. Nearly spherical particles were obtained from solutions and suspensions. Kraft black liquor was used as a model complex suspension with organic and inorganic components. Evaporation rates were measured for single droplets.     

EFFECT OF VIBRATION ON THE DRYING RATE DURING THE FALLING RATE PERIOD

The results of an experimental study on the drying characteristics in vibrated fluidized beds of corn plumule, silica gel and citric acid are presented. Application of vibration was found to enhance the drying rate during the falling rate period. In the optimum range of vibration parameters, the critical moisture content decreased significantly as compared with that in conventional fluidized beds of the same material.     

Structure and Reactivity of Spruce Mechanical Pulp Lignins Part I. Bleaching and Photoyellowing of in situ Lignins

This paper reports the structural investigation of a series of in situ spruce lignins in wood, thermomechanical pulp (TMP) and the corresponding bleached (BTMP) and photoyellowed (YBTMP) samples. This was achieved by using an original two-step degradative technique, thioacidolysis followed by Raney nickel desulfuration. The determination of thioacidolysis monomeric and dimeric products allowed an estimate of various lignin building units and interunit bonds, respectively. It was observed that the thermomechanical and bleaching treatments did not affect spruce lignin structure to an appreciable extent. On the contrary, the photoyellowing treatment caused marked structural changes in lignin, particularly when run in severe conditions. These changes were essentially a decrease in the amount of β-O-4 and β-1 interunit bonds and a relative increase in catechol units and in vanillin end-groups.     

Effects of saliva contamination on bonding performance of self-etching adhesives

Purpose: This study investigated the effects of saliva contamination on bonding performance of two self-etching adhesives. Materials and Methods: Forty caries-free extracted human third molars’ cusps were cut off to expose mid-coronal dentin surfaces. Two one-step self-etching adhesives and the respective resin composite from the same manufacturer (Adper Easy One?+?Filtek Z350 (3?M ESPE); Clearfil S3 Bond?+?Clearfil Majesty (Kuraray Co.)) were applied onto the dentin surfaces for micro-tensile bond strength (MTBS) test. The dentin surfaces were not contaminated (A), were contaminated with saliva before/after priming (B/C), or they were water-sprayed after saliva contamination occurred before/after priming (D/E). The resin–dentin interfaces were analyzed by scanning electron microscopy. After the two adhesives were polymerized on saliva-contaminated or uncontaminated conditions, they were determined by Fourier transform infrared spectroscopy for degree of conversion (DC), and analyzed by AFM spectroscopy for spatial homogeneity of the adhesives. The data were analyzed using factorial design ANOVA and one-way ANOVA. Results: Compared with control group (A), the saliva contamination after priming significantly reduced both dentin MTBS (p?<?0.05). Thorough water-spraying could significantly improve the MTBS of the saliva-contaminated dentin (p?<?0.05) or completely restore it. Saliva contamination deteriorated the resin–dentin adaptation, DC, and spatial homogeneity of adhesives. Conclusions: Saliva contamination had a negative effect on bonding performance of self-etching adhesives regarding their dentin MTBS, resin–dentin adaptation, DC, and spatial homogeneity. However, the effect of saliva contamination on the dentin MTBS was related to the individual adhesive used and the time point of contamination.     

Angiotensin-Converting Enzymes Play a Dominant Role in Fertility

According to the World Health Organization, infertility, associated with metabolic syndrome, has become a global issue with a 10%–20% incidence worldwide. An accumulating body of evidence has shown that the renin–angiotensin system is involved in the fertility problems observed in some populations. Moreover, alterations in the expression of angiotensin-converting enzyme-1, angiotensin-converting enzyme-2, and angiotensin-converting enzyme-3 might be one of the most important mechanisms underlying both female and male infertility. However, as a pseudogene in humans, further studies are needed to explore whether the abnormal angiotensin-converting enzyme-3 gene could result in the problems of human reproduction. In this review, the relationship between angiotensin-converting enzymes and fertile ability is summarized, and a new procedure for the treatment of infertility is discussed.     

Preparation of calcium sulfate dihydrate and calcium sulfate hemihydrate with controllable crystal morphology by using ethanol additive

Calcium sulfate hemihydrate (CSH) with controlled crystal morphology has attracted broad interests due to its superior physical and chemical properties, as well as excellent biological performance. In this study, calcium sulfate dehydrate (CSD) was firstly synthesized via the reaction of H₂SO₄ and Ca(OH)₂ using ethanol as morphology modifier. The prepared CSD was then converted to CSH through a hydrothermal method. It was found that the precipitation time of CSD powders was dramatically shortened and the morphology of CSD crystals was changed from thick tabular to short-rod with the increment in ethanol addition. The finally-obtained CSH crystals were found to have hexagonal prisms shape with smaller aspect ratios. The CSH powder with the desired crystal morphology would provide improved setting behavior and biological performance of the CSH bone cement.     

Structural and electrical characteristics of high-κ Er2O3 and Er2TiO5 gate dielectrics for a-IGZO thin-film transistors

In this letter, we investigated the structural and electrical characteristics of high-κ Er₂O₃ and Er₂TiO₅ gate dielectrics on the amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) devices. Compared with the Er₂O₃ dielectric, the a-IGZO TFT device incorporating an Er₂TiO₅ gate dielectric exhibited a low threshold voltage of 0.39 V, a high field-effect mobility of 8.8 cm²/Vs, a small subthreshold swing of 143 mV/decade, and a high I_on/I_off current ratio of 4.23 × 10⁷, presumably because of the reduction in the oxygen vacancies and the formation of the smooth surface roughness as a result of the incorporation of Ti into the Er₂TiO₅ film. Furthermore, the reliability of voltage stress can be improved using an Er₂TiO₅ gate dielectric.     

用K值法对硫铝酸钙含量进行定量分析研究

以电石渣、脱硫石膏、粉煤灰等工业废渣为原料,并添加氟化钙、二氧化钛、氧化铜等不同种类和掺量的矿化剂,制备以硅酸二钙和硫铝酸钙为主要矿物的多孔胶凝材料;运用X射线衍射技术,通过K值法对硫铝酸钙含量进行定量分析,探讨不同矿化剂的掺入对硫铝酸钙矿物形成的影响。实验结果表明：矿化剂的加入能够降低硫铝酸钙的形成温度,同时能促进硫铝酸钙的形成。氟化钙掺量为1%（质量分数）时硫铝酸钙的含量最高,为12.43%（质量分数）;当氟化钙掺量超过1%时硫铝酸钙含量下降。二氧化钛掺量为0.5%（质量分数）时硫铝酸钙含量最高,达17.85%（质量分数）;当二氧化钛掺量超过1.5%时硫铝酸钙含量下降较为明显。氧化铜适宜的掺量为0.5%~1.0%（质量分数）,掺量超过1.5%时硫铝酸钙含量显著下降。