19 research outputs found

    N-乙基壳聚糖的单晶

    Get PDF
    用光固化法制备N 乙基壳聚糖/聚丙烯酸复合膜.在复合膜中观察到单晶和悬挂着单晶片的微纤.单晶的长和宽约为300~400nm,比常见的晶粒尺寸小得多.与通常单晶的极稀溶液制备条件不同,该单晶是在复合膜中形成的.水的诱导结晶作用和体系的高浓度形成了一种几乎是无限缓慢的结晶条件,单晶正是由于这样条件才能得以形成

    陆桥说和长距离扩散——老观点, 新证据

    No full text

    Study on the Biology of Eimeria tenella,Xiamen Strain

    No full text
    采用单卵囊分离方法从厦门地区饲养的鸡盲肠中获得艾美尔球虫,经显微观察、测量和感染实验,从寄生部位、卵囊形态、孢子化时间和潜伏期等指标测定,实验结果:采用琼脂板方法分离和挑选单卵囊方法进行感染效果理想,单卵囊感染小鸡成功率为60%.该球虫寄生在鸡盲肠部位,其余部位未发现,卵囊形态长卵圆形,长25.80(23.5~28.5),宽20.86(18.5~23.5),长/宽:1.23(1.21~1.27),27℃条件下孢子化时间为20 h.,潜伏期为146 h.与国内一些株进行比较存在差别,确定该艾美尔球虫为柔嫩艾美尔球虫(E im eria tenella),并定名为柔嫩艾美尔球虫厦门株.An Eimeria was separated from caecum of chicken using a new single-oocyst isolation technique in Xiamen.This technique is convenient,and its successful rate is about 60%.The oocyst of Eimeria broadly ovoid,23.5~28.5×18.5~23.5 μm,average 25.8×20.8,the length-to-width ratio ranged 1.21~1.27,with average 1.23,and the wall of oocyst is smoothly,with 2-layered wall,about 2.1~2.7,average 2.5,the outer layer is about 2/3 of total thickness,with light color,the inner layer is thinner than outer layer,with deep color.The sporocysts ellipsoids,11.5~13.5×7.5~9.5,average 12.5×8.0,their length-to-width ratio was 1.42~(1.60),with average 1.56,and cone-shaped stieda body located at the point top,the sporozoites are banana-shaped,9.5~10.5×3.0~4.0,average 10×3.5,they lied widthwise head to tail in the sporocysts and a refractile globules at each end,and sporocyst and oocyst residual bodys are no found,the spolulation time is 20 h,incubation period is about 146 h.The result proved this Eimeria belonged to Eimeria tenella,and comparative to other Eimeria tenella,this strain of Eimeria tenella differs from the other strains,named it Eimeria tenella Xiamen strain.厦门大学校级自选课题资助(2002,Y07010

    PDMS表面上的液滴蒸发实验研究

    No full text
    利用粒子跟踪测速(particle tracking velocimetry,PTV)技术,研究了聚二甲基硅氧烷(polydimethylsiloxane,PDMS)表面上的液滴蒸发行为.发现固液界面上的荧光微球首先向固液界面中心移动,而后发生运动反转,向三相接触线移动.其原因是由于接触线钉扎时接触线附近的蒸发通量较小,从而引起向液滴中心的流动,这种流动将微球带向液滴中心.理论分析了三相接触线的移动特征,发现其移动速度理论值与实验值在同一量级,而移动加速度的实验值较理论值偏大,造成这种偏差的原因是三相接触线处的荧光微球削弱了基底对三相接触线的钉扎作用

    行星滚柱丝杠副额定静载荷计算方法对比分析

    No full text
    行星滚柱丝杠副(Planetary roller screw mechanism,PRSM)是一种新型重载传动装置。额定静载荷是反映其承载能力的关键指标。针对目前PRSM额定静载荷计算方法不统一、计算结果差异大等问题,阐述了以滚珠丝杠、滚动轴承、屈服极限和弹塑性线性强化为基础的4种PRSM额定静载荷计算方法并建立相应计算模型,对比分析了结构参数对4种方法所得额定静载荷的影响规律;建立了PRSM弹塑性接触有限元分析模型,对4种计算方法的准确性进行了对比验证;提出了一种基于滚动轴承标准改进的PRSM额定静载荷计算方法。结果表明,以滚动轴承为基础的额定静载荷计算结果与有限元结果符合较好;所提出的改进计算方法,使其计算误差平均值从17.03%降至8.90%,能够较为精确地计算PRSM的额定静载荷,为行星滚柱丝杠副的设计、选型等提供了理论支撑

    A structural damage detection and classification algorithm based on clone selection

    No full text
    Inspired by identification ability of biological immune system, damage detection and classification problem in structural health monitoring is studied based on the autonomous, adaptive and evolutional artificial immune theory and method. A structural damage detection and classification algorithm based on clone selection principle is proposed. The algorithm samples data of structure model as antigen which stimulates the antibody sets. In order to improve the quality of memory cells, the antibodies go through learning and evolving process including cloning, mutation and selection. At last memory cell sets of high quality are used to detect and classify measured data. The experiment results of the proposed algorithm using benchmark structure model show that the algorithm can identify and classify the structural patterns exactly. The parameter settings which can achieve high classification success rate are proposed on the results analysis of experiment in this paper

    顶空固相微萃取气相色谱质谱联用测定黑臭水体中的4种主要异味物质

    No full text
    采用顶空固相微萃取-气相色谱-质谱联用测定黑臭水体中的4种主要异味物质,即土腥素、2-甲基异茨醇、&beta;-环柠檬醛、&beta;-紫罗兰酮.从萃取纤维、萃取温度、离子浓度、萃取时间、搅拌速率、解吸时间和解吸温度等7个方面对方法进行优化.结果表明,当选用85 &mu;m CAR/PDMS萃取纤维,萃取温度60 ℃, 20%(NaCl/水),1250 r&middot;min~(-1)搅拌速率条件下萃取40 min,并于GC进样口250 ℃高温下解吸4 min时效果最佳.4种异味物质在5-1000 ng&middot;L~(-1)范围内线性良好,检出限在0.73-1.14 ng&middot;L~(-1)之间,加标回收率在92.3%-109%之间.基于上述方法,对安徽省阜阳境内黑臭水体检测,4种目标物质均有检出.实验证明,此方法可用于黑臭水体中异味物质的分析检测.</p

    顶空固相微萃取气相色谱质谱联用测定黑臭水体中的4种主要异味物质

    No full text
    采用顶空固相微萃取-气相色谱-质谱联用测定黑臭水体中的4种主要异味物质,即土腥素、2-甲基异茨醇、β-环柠檬醛、β-紫罗兰酮.从萃取纤维、萃取温度、离子浓度、萃取时间、搅拌速率、解吸时间和解吸温度等7个方面对方法进行优化.结果表明,当选用85 μm CAR/PDMS萃取纤维,萃取温度60 ℃, 20%(NaCl/水),1250 r·min~(-1)搅拌速率条件下萃取40 min,并于GC进样口250 ℃高温下解吸4 min时效果最佳.4种异味物质在5-1000 ng·L~(-1)范围内线性良好,检出限在0.73-1.14 ng·L~(-1)之间,加标回收率在92.3%-109%之间.基于上述方法,对安徽省阜阳境内黑臭水体检测,4种目标物质均有检出.实验证明,此方法可用于黑臭水体中异味物质的分析检测

    Review on astaxanthin production from agricultural wastes by Phaffia rhodozyma

    No full text
    Astaxanthin production by Phaffia rhodozyma is environmentally friendly, safe, and cost effect, but the cost of the medium for culture of Phaffia rhodozyma especially carbon sources is one of the major factors that constrain this process from achieving m

    利用农业废弃物碳源的红法夫酵母生产虾青素研究进展

    No full text
    利用红法夫酵母产虾青素工艺具有绿色、安全、低成本等优点,但培养红法夫酵母的培养基(尤其是碳源)成本是制约该工艺实现大规模生产的主要因素之一。传统的利用纯糖如葡萄糖、蔗糖、木糖等作为红法夫酵母生产虾青素的碳源,效果虽好,但因其价格较高,仅适用于实验室研究和小型发酵生产,不适于大规模工业化生产。如何寻找来源广、价廉且发酵效果好的碳源,降低虾青素的生产成本是发展虾青素产业亟待解决的课题。利用廉价且来源广泛的原料如水果类原料、糖质原料、甘油及废弃木质纤维素类原料等作为碳源能有效降低成本。但这些原料都存在一些问题,比如水果类原料存在季节性及地域性限制,糖蜜类原料供应稳定性方面存在问题,甘油类原料杂质多且存在食品安全隐患,木质纤维素类原料来源广泛、价格低廉,不存在占用耕地等问题,是最有希望用于规模化低成本发酵生产虾青素的原料,但其利用存在一些技术瓶颈。该文介绍了目前利用红法夫酵母生产虾青素的基本情况,并系统地对国内外不同碳源条件下利用红法夫酵母生产虾青素的研究状况进行了综述、比较及分析。最后,对利用红法夫酵母生产虾青素在碳源方面的未来发展趋势及重点研究方向进行了展望
    corecore