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Search Results: 1 - 10 of 74578 matches for " 徐凛 "
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热负载条件对SiO2气凝胶组成及微观结构的影响
廖进军,高朋召,,冯坚
- , 2018, DOI: 10.11951/j.issn.1005-0299.20170343
Abstract: 通过阶梯升温并结合傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等表征手段,研究了不同温度所得SiO2气凝胶的组成和微观结构,在程序升温条件下通过TG-DTG曲线和无模式函数法研究了SiO2气凝胶热重行为的变化.结果表明:SiO2气凝胶主要由7~9 nm球状颗粒构成类线形团簇,进而以团簇为骨架构成三维网络多孔结构;阶梯升温下,随着热处理温度的升高,气凝胶中Si—O—Si基团的摩尔分数逐渐增加,Si—OH和Si—OC2H5的摩尔分数逐渐降低,1 073 K时Si—OH基本消失,但存在6.59%的Si—OC2H5基团;气凝胶颗粒逐渐长大,部分骨架坍塌,温度达到1 273 K时,颗粒长大至约50 nm,团簇彻底消失,材料发生明显烧结.程序升温下,升温速率越高,气凝胶的热稳定性越好;材料的失重过程分为3个阶段:当反应转化率α < 30%时,主要发生硅羟基(Si—OH)间的缩合;当30% < α < 70%时,主要是硅羟基(Si—OH)与/或硅乙氧基(Si—OC2H5)之间的缩合;当α>70%时,主要是硅乙氧基(Si—OC2H5)之间的缩合.
Composition and microstructure of SiO2 aerogels treated at different temperatures were studied using the ladder-elevating temperature combined with FT-IR, XPS, SEM, and TEM. The change of thermogravimetric behavior of SiO2 aerogels under temperature-programmed conditions was investigated using TG-DTG curve and model-free kinetics. Results showed that SiO2 aerogel was mainly composed of spherical particles ranged between 7 and 9 nm. These particles formed the class alignment clusters, which continued to work as skeletons to from a three-dimensional network porous structure. Under ladder-elevating temperature condition, with the increase of treatment temperatures, content of Si—O—Si group increased while that of Si—OH and Si—OC2H5 groups both decreased. When the temperature reached 1 073 K, Si—OH group almost disappeared and content of Si—OC2H5 group decreased to 6.59%. Nanoparticles in SiO2 aerogel grew slowly, resulting in the collapse of skeletons. When the temperature rose to 1 273 K, the particle size grew about 50 nm, clusters disappeared completely, and SiO2 aerogels sintered obviously. Under temperature-programmed condition, the faster the heating rate, the better the thermal stability of SiO2 aerogel. The weight-loss process of SiO2 aerogel was mainly divided into three steps: when α < 30%, the weight-loss process was controlled via condensation reaction between Si—OH; when 30% < α < 70%, it was mainly controlled via the condensation reaction between Si—OH and/or Si—OC2H5; when α>70%, it was mainly controlled via condensation reaction of Si—OC2H5.
斑节对虾育苗中“红圈病”的防治
严正
海洋科学 , 1994,
Abstract:
斑节对虾生产性育苗中的几个问题
严正
海洋科学 , 1994,
Abstract:
九孔鲍的人工苗种生产技术
严正
海洋科学 , 2001,
Abstract:
大黄鱼人工苗种生产技术
严正
海洋科学 , 1999,
Abstract:
九孔鲍四倍体诱导的研究
严正
生物技术通报 , 2008,
Abstract: 采用二倍体鲍卵子,抑制其第一极体、抑制其第一极体和第二极体诱导四倍体,用三倍体鲍卵子与普通鲍精子受精并抑制其第一极体,以及用三倍体鲍的其它方法诱导四倍体。用倍体分析仪检测DNA相对含量以判别其倍性。实验结果,先后共培育出存活的四倍体鲍239个,个体大小为2.5~6.0cm;挑选性腺发育较好的四倍体鲍(包括雌雄),与普通鲍杂交繁育三倍体,先后共培育出10批次,培育出的苗量共计15.8万个。
光照强度对九孔鲍幼虫及幼鲍生长存活的影响
严正
水产学报 , 2001,
Abstract: 在自然光周期下,分别在高温长光照和低温短光照的两个季节,采用控制光照强度的方法进行对九孔鲍幼虫及幼鲍50d左右培育的小型试验.结果表明,光照强度对附着基上摄食微藻的幼虫及幼鲍生长和存活等有重要的影响;对幼虫及幼鲍最适宜的光照强度,在高温长光照下为700~1200lx,在低温短光照下为1300~2000lx.选用适宜的光照强度在高温长光照和低温短光照下先后进行了3次批量育苗试验,获得了与小型试验相同的结果.
海带_江蓠浸渍光合细菌菌液后喂养九孔鲍的效果
严正
水产学报 , 2001,
Abstract: 使用海带、江蓠浸渍光合细菌的不同浓度和时间对大小两种不同规格九孔鲍的生长效果进行试验.结果表明,光合细菌促进养成鲍的生长效果,因海带、江蓠浸渍光合细菌的浓度和时间而异,浸渍浓度越大,浸渍时间越长,则其促进生长作用越明显;海带、江蓠浸渍光合细菌的浓度和时间分别为150×10-6(v/v)和3h~4h或200×l0-6(v/v)和2h~3h的试验组鲍的平均壳长增长率都比对照组提高了5%以上,最高提高11.5%左右(p<0.05).
三倍体九孔鲍的育种和养成技术研究
严正
水产学报 , 2002,
Abstract: 当50%九孔鲍受精卵出现第一极体后,以6-dmap为诱导剂,用不同的浓度和不同的持续时间抑制第二极体的释放诱导三倍体;并进行了生产性苗种培育和养成试验.结果表明,6-dmap的诱导浓度为300μmol@dm-3、诱导持续时间为10min时,其胚胎的三倍体率为90%以上,并且胚胎的孵化率高达85%,幼体的畸形率较低,为50%~55%;经过7个月培育,试验组养成鲍的三倍体率为65%以上;试验组养成鲍的平均壳长比对照组增长10%,平均体重比对照组增重30%.与二倍体鲍相比较,三倍体鲍在壳长增长和体重增重等方面,显示了显著的优势[t>t0.01(58)].
外源激素对大黄鱼的催产效果
严正
水产学报 , 1999,
Abstract:
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