气氛和化学组成对高铁煤灰熔融特性的影响机理

采用灰熔点仪、XRD和热力学模拟,研究气氛和化学组成对高铁煤灰熔融特性的影响机理。研究结果表明,灰熔融温度随铁含量、钙含量或硅铝比增加而降低。弱还原气氛下低钙或低硅铝比煤灰熔融存在明显的初始熔融阶段,熔融过程遵循“软化-熔融”机理,而空气气氛下高钙或高硅铝比煤灰熔融过程属于“熔融-溶解”机理。弱还原气氛下铁含量增加显著促进石英和钙长石熔融,空气气氛下钙含量增加促进刚玉和石英熔融或转化为钙基硅铝盐。弱还原气氛下液相含量随硅铝比或铁含量增加而增加,液相黏度随钙含量或铁含量增加而降低,促进熔融传质;空气气氛下低钙或低硅铝比煤灰中铁存在于含铁固溶体,导致液相黏度高或液相含量低,熔融传质受阻。     

气氛和化学组成对高铁煤灰熔融特性的影响机理

采用灰熔点仪、XRD和热力学模拟,研究气氛和化学组成对高铁煤灰熔融特性的影响机理。研究结果表明,灰熔融温度随铁含量、钙含量或硅铝比增加而降低。弱还原气氛下低钙或低硅铝比煤灰熔融存在明显的初始熔融阶段,熔融过程遵循“软化-熔融”机理,而空气气氛下高钙或高硅铝比煤灰熔融过程属于“熔融-溶解”机理。弱还原气氛下铁含量增加显著促进石英和钙长石熔融,空气气氛下钙含量增加促进刚玉和石英熔融或转化为钙基硅铝盐。弱还原气氛下液相含量随硅铝比或铁含量增加而增加,液相黏度随钙含量或铁含量增加而降低,促进熔融传质;空气气氛下低钙或低硅铝比煤灰中铁存在于含铁固溶体,导致液相黏度高或液相含量低,熔融传质受阻。     

硅粉微波烧结的热力学动力学计算

本文采用微波烧结工艺,将硅粉在氩气气氛下与氮气直接反应,合成了氮化硅粉,利用XRD手段对物相进行分析,并对硅粉氮化的过程进行了热力学及动力学上的计算,通过计算得出了硅粉直接氮化反应的活化能Ea及指前因子A,得出了硅粉微波烧结直接氮化反应为动力学控制反应的结论,解释了硅粉氮化反应只有在较高温度才能发生的原因。     

热处理气氛对电子辐照直拉硅中氧沉淀的影响

对经过电子辐照的n型[111]晶向直拉硅样品在不同气氛下进行了热处理,对比研究了热处理气氛对电子辐照直拉硅中的缺陷形貌、间隙氧含量的变化以及清洁区的影响.实验结果表明,热处理气氛对辐照样品中的缺陷形貌影响较大:氩气氛下退火样品体内的缺陷以位错环为主而氮气氛下则主要是层错,并对此现象的机理进行了讨论;经历不同气氛快速预处理再进行高温一步退火后,辐照样品表面会产生一定宽度的清洁区,而氮气氛下清洁区宽度较窄;通过傅里叶变换红外光谱仪检测间隙氧含量的变化发现氮气氛下退火的样品间隙氧含量下降较多,说明氮气氛热处理更有利于氧沉淀的生成.     

在流动NH_3中催化剂对硅粉氮化的影响

本文研究了在流动NH_3中催化剂对硅粉氮化率、产物相组成的影响。流动NH_3经催化剂后已100％的分解了。未经催化剂的流动NH_3甚至在温度高达1380℃时分解率还只有88％。将上述两种气氛相比,前一种气氛中氨原子N的浓度比后一种气氛中的要高得多。所以,用经催化剂的流动NH_3作氮化气氛和未经催化剂的流动NH_3作氮化气氛相比,硅粉的起始氮化温度和最终氮化温度分别降低了约150℃和40℃,氮化时间也相应缩短了。在经催化剂的流动NH_3中硅粉氮化率随着NH_3流量的增加而提高。这些结果表明:在流动NH_3中氨原子N的存在是加速硅粉氮化的主要因素。     

流化床法除去微硅粉游离碳工艺研究

本文采用流化床作为反应装置,改变进入流化床反应器气体的流速使微硅粉达到最佳流化效果,通过对比空气气氛和氧气气氛下微硅粉的除碳效果,调整反应温度、反应时间选择最佳反应条件.结果表明:在氧气气氛下,反应温度700℃,反应时间3.0h,微硅粉中游离碳含量从1.25％下降到0.05％,烧失量从3.36％下降到0.92％,微硅粉中二氧化硅纯度从81.62％提高到85.92％;在空气气氛下,反应温度为700℃,反应时间为3.0h,微硅粉中游离碳含量从1.25％下降到0.027％,烧失量从3.36％下降到0.99％,微硅粉中二氧化硅纯度从81.62％提高到86.97％.本技术能够有效除去微硅粉中游离碳杂质,提高微硅粉的纯度,提高了产品的附加值.     

聚碳硅烷先驱丝的负压氧化特性研究

采用负压热氧化法对聚碳硅烷(PCS)先驱丝进行不熔化处理,并研究了气氛压力和处理温度对PCS先驱丝的增重率、硅氢反应程度、凝胶含量、化学结构及其热解特性的影响.结果表明:在负压热氧化作用下,先驱丝的增重率、硅氢反应程度、凝胶含量以及陶瓷产率均随气氛压力和处理温度的降低而降低.当气氛压力为-0.02 MPa时,随着处理温度从195 ℃降低到175 ℃,先驱丝的增重率从9.98%降低到2.80%,硅氢反应程度从63.62% 降低到21.85%,凝胶含量从73.53%降低到1.98%,陶瓷产率从87.81% 降低到81.29%.     

钙铁硅铁磁体微晶玻璃热处理气氛的研究

使用XRD,DTA,VSM和穆斯堡尔谱等分析测试手段,对不同气氛下晶化热处理的含水量的B2O3,P2O5钙铁硅微晶玻璃的晶相结构和性质进行了比较深入的研究,研究结果表明,在氧化性气氛下热处理的钙铁硅微晶玻璃以赤铁矿为主;必须在还原性气氛下热处理才能得到以磁铁矿为主要晶相的铁磁体微晶玻璃。     

掺铝钕高硅氧玻璃的制备及光谱性能研究

采用分相酸溶工艺制备了Na2O-B2O3-SiO2体系纳米多孔玻璃,并以此为基质进行了钕铝掺杂的实验,制备了掺钕铝高硅氧玻璃,光谱分析表明,所制得的玻璃在1064 nm附近有明显的发射峰.研究了掺杂浓度、烧结气氛对玻璃光谱性能的影响,分析了铝离子在共掺杂玻璃中的作用.结果表明在浓度为0.2 mol/L的Nd(NO3)3溶液中制备的掺杂高硅氧玻璃发光强度最强,还原气氛下烧结的掺杂高硅氧玻璃光谱强度高于在空气中烧结得到的高硅氧玻璃,同时在还原条件下铝离子能够明显的提高玻璃的发光强度.     

聚碳硅烷先驱丝的负压氧化特性研究（英文）

采用负压热氧化法对聚碳硅烷(PCS)先驱丝进行不熔化处理,并研究了气氛压力和处理温度对PCS先驱丝的增重率、硅氢反应程度、凝胶含量、化学结构及其热解特性的影响。结果表明:在负压热氧化作用下,先驱丝的增重率、硅氢反应程度、凝胶含量以及陶瓷产率均随气氛压力和处理温度的降低而降低。当气氛压力为-0.02 MPa时,随着处理温度从195℃降低到175℃,先驱丝的增重率从9.98%降低到2.80%,硅氢反应程度从63.62%降低到21.85%,凝胶含量从73.53%降低到1.98%,陶瓷产率从87.81%降低到81.29%。     

Evaluation of surfactant-aided degumming of vegetable oils by membrane technology

The first step in the process of vegetable oil refining is degumming, in which phospholipids and mucilaginous gums are removed that otherwise result in a low-grade oil. A membrane process is remarkably simple yet potentially offers many advantages in degumming. Studies were conducted on surfactant-aided membrane degumming with soybean and rapeseed oils in a magnetically stirred flat membrane batch cell with different types of microfiltration membranes. The reduction of phospholipids in soybean oil was in the range of 85.8–92.8% during the membrane process. The phosphorus content of membrane permeates of soybean oil was in the range of 20–58 mg/kg. Crude rapeseed oil contained higher amount of nonhydratable phospholipids and hence resulted in lower reduction in phospholipids, in the range of 66.4–83.2%. Addition of hydratable phospholipids could improve the efficiency of degumming in the membrane process without using any electrolyte, resulting in improvement of quality as well as quantity of the phospholipids.     

Physiological effects of alarm chemosignal emitted during the forced swim test

Two experiments were conducted. In the first, male rats were immersed for 25 min in fresh water or water previously swum in by another rat. Control rats were not immersed in water. Rats tested in water previously swum in by another rat were significantly less immobile than rats tested in fresh water. Water immersion resulted in significant increases in serum corticosterone, glucose, and phosphorus levels, a decrease in potassium levels, and a higher phosphorus/potassium ratio, compared to nonimmersed controls regardless of water condition. When the two water-immersed groups were compared, rats tested in previously swum water had significantly higher glucose and significantly lower potassium levels and a higher phosphorus/potassium ratio than rats tested in fresh water. Immobility times were significantly correlated with the phosphorus/potassium ratio. In the second experiment, blood gases were measured prior to testing and at 25 min after immersion in rats tested in fresh and previously swum water. Rats in soiled water hypoventilated to a significantly greater extent than rats in fresh water but did not differ significantly in blood oxygenation. These two studies demonstrate that alarm chemosignals can produce physiological effects in conspecifics.     

Effects of decomposing rice straw on growth of and nitrogen fixation byRhizobium

Five phenolic compounds produced by decomposing rice straw and sterile extracts of decomposing rice straw in soil were very inhibitory to growth of three strains ofRhizobium. The effects were additive and in several instances synergistic. The phenolic compounds also reduced nodule numbers and hemoglobin content of the nodules in two bean (Phaseolus vulgaris) varieties. Extracts of decomposing rice straw in soil (same concentration as in the soil) significantly reduced N₂ fixation (acetylene reduction) in Bush Black Seeded beans. This may explain in part the great reduction in soybean yields in Taiwan following rice crops when the rice stubble is left in the field.     

Streptozotocin-Induced Diabetes Causes Changes in Serotonin-Positive Neurons in the Small Intestine in Pig Model

Serotonin (5-hydroxytryptamine or 5-HT) is an important neurotransmitter of the central and peripheral nervous systems, predominantly secreted in the gastrointestinal tract, especially in the gut. 5-HT is a crucial enteric signaling molecule and is well known for playing a key role in sensory-motor and secretory functions in the gut. Gastroenteropathy is one of the most clinical problems in diabetic patients with frequent episodes of hyperglycemia. Changes in 5-HT expression may mediate gastrointestinal tract disturbances seen in diabetes, such as nausea and diarrhea. Based on the double immunohistochemical staining, this study determined the variability in the population of 5-HT-positive neurons in the porcine small intestinal enteric neurons in the course of streptozotocin-induced diabetes. The results show changes in the number of 5-HT-positive neurons in the examined intestinal sections. The greatest changes were observed in the jejunum, particularly within the myenteric plexus. In the ileum, both de novo 5-HT synthesis in the inner submucosal plexus neurons and an increase in the number of neurons in the outer submucosal plexus were noted. The changes observed in the duodenum were also increasing in nature. The results of the current study confirm the previous observations concerning the involvement of 5-HT in inflammatory processes, and an increase in the number of 5-HT -positive neurons may also be a result of increased concentration of the 5-HT in the gastrointestinal tract wall and affects the motor and secretory processes, which are particularly intense in the small intestines.     

污泥生物炭中氮硫行为及环境效应研究进展

污泥生物炭中氮硫元素含量高,其氮硫行为和环境效应对全球气候变化的影响不容忽视。以往的研究中,研究者往往以富碳生物炭作为主要研究对象,关注碳对全球气候变化的行为和功效,而对氮硫元素的作用关注不够。本文从原始污泥基本性质到其热解过程,再到生物炭的老化,逐步对污泥生物炭整个生命周期内氮硫的行为及其环境效应研究进行综述,并对未来应注重开展的研究方向进行展望,为生物炭中氮硫元素固定、释放及与之关联的环境效应和温室气体排放控制研究提供理论基础。分析表明,污泥中氮元素含量普遍高于硫元素,且热解过程中氮比硫更容易转移至气相产物。氮硫元素随热解温度的增加,在三相产物中的分配都是炭中持续减少,油中先增后减,气中一直增加。高温（＞800℃）条件下,气相中的氮含量高于固相,而硫元素则仍然主要存在于固相中。污泥生物炭老化及其环境效应研究表明,污泥生物炭氮硫元素与土壤的相互作用及其温室效应问题在今后的研究中应引起重视。     

分别测定双磷酸酯阻燃增塑剂中氯和溴含量的方法

介绍利用Ｂｒ的特征反应使系统中的Ｂｒ全部转化后，分别测定阻燃增塑剂中氯与溴含量的一种新方法。该方法分析速度快，操作简单，测定结果准确，重现性好，可应用于生产中的控制分析。     

Incubating superphosphate in ‘dry’soil can reduce its effectiveness

Single superphosphate was incubated for six months at 25°C in soil which had been subject to one of three moisture treatments. These were: dried in a glasshouse, dried at a constant temperature of 25°C, or moist soil. Phosphorus (P) effectiveness was then compared with effectiveness of P from freshly-applied superphosphate using yields of wheat (Triticum aestivum) and triticale (×Triticosecale) tops in pot experiments.Incubation in soil which had been dried at 25°C did not decrease the effectiveness of the P. Incubation in moist soil decreased it to about 20% of the effectiveness of freshly-applied P in one case and to about 50% in the other case. Incubation in soil which had been dried in a glasshouse also decreased its effectiveness. The decrease varied with conditions, but in two cases the P was 70% as effective as freshly-applied P, and in one case only 45% as effective. Presumably sufficient moisture was present in the soil dried in the glasshouse to enable water-soluble P present in the fertilizer to react with the soil.     

H-Ferritin Produced by Myeloid Cells Is Released to the Circulation and Plays a Major Role in Liver Iron Distribution during Infection

During infections, the host redistributes iron in order to starve pathogens from this nutrient. Several proteins are involved in iron absorption, transport, and storage. Ferritin is the most important iron storage protein. It is composed of variable proportions of two peptides, the L- and H-ferritins (FTL and FTH). We previously showed that macrophages increase their expression of FTH1 when they are infected in vitro with Mycobacterium avium, without a significant increase in FTL. In this work, we investigated the role of macrophage FTH1 in M. avium infection in vivo. We found that mice deficient in FTH1 in myeloid cells are more resistant to M. avium infection, presenting lower bacterial loads and lower levels of proinflammatory cytokines than wild-type littermates, due to the lower levels of available iron in the tissues. Importantly, we also found that FTH1 produced by myeloid cells in response to infection may be found in circulation and that it plays a key role in iron redistribution. Specifically, in the absence of FTH1 in myeloid cells, increased expression of ferroportin is observed in liver granulomas and increased iron accumulation occurs in hepatocytes. These results highlight the importance of FTH1 expression in myeloid cells for iron redistribution during infection.     

Lymphatic Transport of α-Linolenic Acid and Its Conversion to Long Chain n-3 Fatty Acids in Rats Fed Microemulsions of Linseed Oil

In the present study we evaluated the uptake of ALA and its conversion to EPA + DHA in rats given linseed oil (LSO) in native form or as a microemulsion in whey protein or in lipoid. In a single oral dose study in which rats maintained on rodent pellets deficient in ω-3 fatty acids were intubated with 0.35 g LSO in lipoid, the amount of ALA present in lymph was increased reaching a maximum concentration of 16.23 mg/ml at 2.5 h. The amount of ALA present in lymph was increased to a maximum level of 10.95 mg/ml at 4 h in rats given LSO as a microemulsion in whey protein. When LSO was given without emulsification, the amount of ALA present in lymph was found to reach a maximum level of 7.08 mg/ml at 6 h. A similar result was observed when weaning rats were intubated with 0.15 g of LSO per day for a period of 60 days. Higher levels of ALA by 41 and 103 % were observed in lymph lipids of rats given microemulsions of LSO in whey protein and in lipoid respectively as compared to rats given LSO without pre-emulsification. Very little conversion of ALA to EPA and DHA was observed in lymph lipids but higher amounts of EPA + DHA was observed in liver and serum of rats given LSO in microemulsion form. This study indicated that ALA concentration in lymph lipids was increased when LSO was given in microemulsion form in lipoid and further conversion to EPA and DHA was facilitated in liver and serum.     

SUCNR1 Is Expressed in Human Placenta and Mediates Angiogenesis: Significance in Gestational Diabetes

Placental hypervascularization has been reported in pregnancy-related pathologies such as gestational diabetes mellitus (GDM). Nevertheless, the underlying causes behind this abnormality are not well understood. In this study, we addressed the expression of SUCNR1 (cognate succinate receptor) in human placental endothelial cells and hypothesized that the succinate–SUCNR1 axis might play a role in the placental hypervascularization reported in GDM. We measured significantly higher succinate levels in placental tissue lysates from women with GDM relative to matched controls. In parallel, SUCNR1 protein expression was upregulated in GDM tissue lysates as well as in isolated diabetic fetoplacental arterial endothelial cells (FpECAds). A positive correlation of SUCNR1 and vascular endothelial growth factor (VEGF) protein levels in tissue lysates indicated a potential link between the succinate–SUCNR1 axis and placental angiogenesis. In our in vitro experiments, succinate prompted hallmarks of angiogenesis in human umbilical vein endothelial cells (HUVECs) such as proliferation, migration and spheroid sprouting. These results were further validated in fetoplacental arterial endothelial cells (FpECAs), where succinate induced endothelial tube formation. VEGF gene expression was increased in response to succinate in both HUVECs and FpECAs. Yet, knockdown of SUCNR1 in HUVECs led to suppression of VEGF gene expression and abrogated the migratory ability and wound healing in response to succinate. In conclusion, our data underline SUCNR1 as a promising metabolic target in human placenta and as a potential driver of enhanced placental angiogenesis in GDM.