3 种抗氧化剂对硅酸钠胁迫下粉红单端孢（Trichothecium roseum）孢子生存能力的保护作用比较研究

本实验研究了抗坏血酸（VC）、还原性谷胱甘肽（reduced glutathione,GSH）和半胱氨酸（cysteine,Cys）3 种抗氧化剂分别作为预防剂和治疗剂对硅酸钠和对应pH值溶液胁迫下粉红单端孢（Trichothecium roseum）孢子存活力的保护作用。结果表明,3 种抗氧化剂均能使硅酸钠胁迫下孢子的生存能力部分恢复,而使对应pH值胁迫下孢子的生存能力80%恢复;3 种抗氧化剂中VC的保护效果要优于GSH和Cys;3 种抗氧化剂作为预防剂的效果要优于其治疗效果。     

流量变化对液固流化床瞬态流化特性的影响

流化床开车、停车及反应控制过程中,对流化床的流量进行调节的不当操作可能致使局部热点的出现,使操作状态恶化,故充分认识流化床的非稳态流化特性具有重要意义。选用直径为0.45 mm的玻璃珠,在厚15 mm、宽400 mm、高1200 mm的二维流化床中进行液固流态化实验,研究了流量变化对颗粒浓度的影响。实验发现,当流量下降时,流化床中形成了浓-稀相突跃界面,且界面前方有过渡段存在;而当流量上升时,流化床中形成的是由浓到稀的过渡段,变化过程中其浓度波动要远大于流量下降时,且需要更长的时间来达到稳定。以相同时间完成流量下降时,流量变化量较小,则流化床各段的平均颗粒浓度变化速度较慢,同时不利于浓-稀相界面的形成。流量下降幅度相等、流量变化时间延长,则使流化床中的颗粒浓度变化速度呈现先慢后快的特点,同时流量变化较慢,则浓-稀相突跃界面不易形成。     

Evaluation on the phagocytosis of apoptotic spermatogenic cells by Sertoli cells in vitro through detecting lipid droplet formation by Oil Red O staining

During spermatogenesis, more than half of the differentiating spermatogenic cells undergo apoptosis before they mature into spermatozoa. Ultrastructure studies showed that the formation of lipid droplets in Sertoli cells was associated with phagocytosis of residual bodies and apoptotic germ cells by Sertoli cells. Here, a relationship between the phagocytosis of apoptotic spermatogenic cells and lipid droplet formation in Sertoli cells was studied in vitro by Oil Red O (ORO) staining. The results confirmed that the formation of lipid droplets was a result of phagocytosis of apoptotic spermatogenic cells in Sertoli cells. By comparing phagocytosis of apoptotic spermatogenic cells and thymocytes by Sertoli cells to that by macrophages, we demonstrated that the lipid droplets accumulation in phagocytes depended on phagocytosed apoptotic cell type, but not phagocyte type. However, the size of lipid droplets was related to the type of phagocytes. By this approach, we found that Sertoli cells at different postnatal stages of development had a similar phagocytic ability. These results suggested that the detection of lipid droplets by ORO staining was a practical method to evaluate the phagocytic functions of Sertoli cells in vitro. This approach could also be considered as an in vitro model to study the lipid formation, metabolism, and function in Sertoli cells.     

日粮补充L-亮氨酸对超早期断奶宫内发育迟缓仔猪肠道免疫功能的影响

目的:研究L-亮氨酸对超早期断奶宫内发育迟缓(intrauterine growth retardation,IUGR)仔猪肠道免疫功能的调节作用。方法:选取14日龄断奶的正常初生体质量(normal birth weight,NBW)和IUGR新生仔猪各16头,分别饲喂基础日粮或添加0.35%L-亮氨酸实验日粮,即4个处理组,每组8头猪。结果:与NBW仔猪相比,IUGR仔猪血清溶菌酶活力和补体3(complement-3,C3)水平显著降低(P0.05),空肠和回肠中杯状细胞(goblet cells,GC)和淋巴细胞(intraepithelial lymphocytes,IEL)数量显著减少(P0.05),回肠中肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)含量显著升高(P0.05),白细胞介素10(interleukin-10,IL-10)含量显著降低(P0.05)。另外,IUGR仔猪回肠TNF-αm RNA表达量显著升高(P0.05),IL-10 m RNA表达量显著降低(P0.05)。日粮添加0.35%L-亮氨酸后,IUGR仔猪血清溶菌酶活力、C3和C4水平显著升高(P0.05),回肠中GC数量及十二指肠和空肠中IEL数量显著增加(P0.05),回肠中IL-10含量显著升高(P0.05),并且IL-2和IL-10 m RNA表达量显著升高(P0.05)。结论:IUGR会引起超早期断奶仔猪肠道黏膜发生炎症反应和肠道生长发育受限。L-亮氨酸可以有效缓解IUGR引起的肠道黏膜损伤,改善仔猪肠道的免疫功能。     

膜厚度对沥青流变性能的影响研究

采用动态剪切流变仪(DSR)测试了4种沥青结合料及其短期老化产物在不同膜厚度下的流变性能.采用基于CAM模型构建的复数剪切模量主曲线分析了不同膜厚度下沥青流变性之间的差异,通过Black diagram曲线初步分析了沥青流变性随膜厚度变化的机理及影响因素,进一步提出用膜厚度指数B来量化分析沥青流变性随膜厚度变化的敏感性.结果表明:随着膜厚度的降低,沥青复数剪切模量呈现减小趋势,且此趋势因沥青种类不同而有所差异;膜厚度指数B能够很好地评价基质沥青流变性随膜厚度变化的敏感性,但因改性和老化作用改变了沥青结合料的分子结构及尺寸组成,因此对于改性和老化沥青,膜厚度指数B的适用性有所降低.     

用边界元法计算加速器元件的电磁场

本文试图采用基于边界积分方程的一种边界分元的数值计算方法——边界元法,来分析我所2×6MV串列加速器的束流光学元件的电磁场。因为该方法不同于有限差分法和有限单元法的新方法,而且它具有以下优点:边界无法所依据的数学原理简单、易懂,便于推广应用;数值计算精度高;目前广泛应用的有限单元法和有限差分法都属于‘域法’,即在整个求解域里划分成许多细小的单元或网格,然后把各单元或网格换成简单的等价模型,再把它们联系起来。而边界元法只需要在边界上剖分、离散。因此,解算一个问题所要的方程组少,输入数据简单等。     

高温空气平焰燃烧过程的数值分析与比较

通过数值模拟方式分析了高温空气平焰燃烧的特点。并从火焰结构、能量利用与NOx排放等角度，与常规平焰燃烧进行了比较。数值模拟结果显示。通过助燃空气预热来高效回收烟气余热，烟气再循环来获得低氧燃烧环境，减少NOx的生成与排放，在相同的加热能力与相同的NOx排放条件下，高温空气平焰燃烧可节能45％，减少温宣气体排放45％。     

熔体快淬LaFe11．5Si1．5的巨大磁熵变

采用熔体快淬法制备了LaFe11．5Si1．5化合物。利用X射线衍射和能谱分析测定了熔体快淬带的相组成和元素分布：利用磁性能测试结果计算了磁熵变。结果表明：熔体快淬可以得到元素分布均匀的LaFe11．5Si1．5薄带，其相组成为NaZn13型LaFe11．5Si1．5化合物和大量α-Fe。退火后，快淬带中的α-Fe含量大大降低，得到了近似单相的LaFe11．5Si1．5化合物。由磁性能测试并经计算发现，快淬带经1000℃，6h时效后具有巨大的磁熵变。由此可见，熔体快淬可成为一种制备更廉价的高性能磁致制冷材料的新方法。     

Oxidizing Vacancies in Nitrogen‐Doped Carbon Enhance Air‐Cathode Activity

Oxidizing vacancies in nitrogen‐doped carbon have recently been reported to enhance the oxygen reaction activity of air cathodes, but their specific role has remained elusive and controversial. Herein, the critical role of oxidizing the vacancies in enhancing the oxygen reduction reaction for metal–air battery is identified with density functional theory. Deliberate introduction of oxygen‐enriched vacancies in nitrogen‐doped carbon is shown experimentally to provide superior oxygen reduction activity. In situ X‐ray powder diffraction gives direct observation of the oxygen reactions in a zinc–air battery catalyzed by vacancy‐enriched oxidized carbon; the intensity changes of the carbon peak show continuous chemisorption of oxygen intermediates on the carbon cathode during discharge. The air‐cathode performance is shown to exceed that with Pt/C+IrO₂ catalysts.     

Pulsed vacuum drying (PVD) technology improves drying efficiency and quality of Poria cubes

The objective of this research was to examine the drying characteristics of pulsed vacuum drying (PVD) system as an alternative drying technology for a functional food—Poria cocos. Poria cubes in thin layer were dried at different temperatures (55, 65, and 75°C), vacuum duration (5, 15, and 25?min), and atmospheric pressure duration (4, 8, and 12?min) to evaluate the operating conditions on the drying kinetics and quality attributes of P. cocos. The quality attributes included volume shrinkage ratio, firmness, water-soluble polysaccharide content. Volume shrinkage ratio was determined by image processing technology and analyzed by Bigot’s curves. The material internal temperature was also recorded during the whole drying process. Considering the drying rate and quality attributes, drying temperature of 65°C, vacuum pressure duration of 15?min, and atmospheric pressure duration of 4?min were proposed as the most favorable drying conditions for drying Poria cubes. The current work indicates PVD is a promising technology for P. cocos drying as it not only enhances the drying process but also improves the quality attributes of it.