大蒜花苞的生物反应器扩繁     

王菁菁  贾明良  张本厚  刘刃  陈集双 《科技通报》2013,29(3)

利用间歇浸没式生物反应器对大蒜花苞进行培养,研究了不同外植体类型对大蒜种苗生长的影响,并与传统固体培养方式进行了比较,随后对得到的微型鳞茎进行驯化栽培研究.结果表明:(1)不同生长阶段的大蒜外植体进行60 d的培养,反应器中Ⅱ型(固体培养基培养20 d的花苞)每个容器鳞茎数(942.40个)和增殖系数(23.56)均是I型(新鲜花苞)的1.15倍;Ⅱ型每个容器生物量(8.82 g)和平均鲜重(0.22 g)均是I型的1.1倍.因此,Ⅱ型比I型花苞更适合作为间歇浸没式生物反应器培养的外植体.(2)生物反应器培养的外植体每个容器生物量(8.48 g)是固体培养基培养的70.67倍,平均鲜重(0.26 g)是后者的4.33倍,增殖系数(21.22)是后者的4.21倍,每个容器鳞茎数(848.80个)是后者的84.37倍.因此,间歇浸没式生物反应器培养方式优于固体培养基培养方式.(3)将生物反应器培养得到的微型鳞茎按照直径大小分为①型,4.0～6.0 mm;②型,3.0～4.0 mm;③型,＜3.0 mm.直径大小为3.0～4.0 mm的鳞茎,即②型发芽率最高,为68.11％,生根率和存活率分别为57.83％和85.73％,是水培鳞茎的适宜类型.利用育苗盘进行栽培,同样得到直径大小为3.0～4.0 mm的鳞茎表现最佳,其发芽率最高,为60.43％,生根率和存活率分别为58.43％和89.33％,鳞茎苗生长状态最好,是鳞茎栽培的适宜类型.  相似文献   

双离合式自动变速器换挡控制方法的研究     

夏伟强  蔡锦波  任华林  滕伯印 《科技通报》2013,(1):106-109

双离合式自动变速器换挡能够实现平稳快速的动力性换挡,提高乘坐的舒适性。由双离合器式自动变速器换挡过程的分析可知,当上一档位的离合器分离,下一档位的离合器滑摩的时候,由于两个档位变速比的差别,为了使换挡过程中车速平稳变化,没有明显的冲击,必须在这过程中,对发动机转速进行有效控制以匹配下一档位的输入轴转速。本文研究双离合式自动变速器换挡控制方法,编写相应的换挡控制程序,对发动机和离合器同时进行有效的控制。实验结果表明,本文采用的控制方法实现了汽车平稳变速。  相似文献   

2012年度国家自然科学基金工程与材料科学领域“人才板块”项目申请与资助概况浅析     

王之中  丁玉琴  孔明  任玉荣  江卫东  马维纲  车成卫  黎明 《中国科学基金》2013,(3):163-166

引言人才板块项目作为国家自然科学基金委员会(以下简称自然科学基金委)资助格局中的重要组成部分,项目申请数占总申请量的45%左右,以国家杰出青年科学基金和创新研究群体科学基金为代表的人才基金项目已成为国家自然科学基金(以下简称科学基金)系列中很有影响的两张"名片"。青年科学基金、优秀青年科学基金、国家杰出青年科学基  相似文献   

基于MULTISIM的彩灯控制电路仿真     

李海燕  任文平  李鹏  李威威  池宗琳 《中国科技信息》2013,(24):140-142

本文基于NI Multisim 11.0的模拟仿真功能,以彩灯控制电路为例,对其时钟信号产生电路、顺序脉冲产生电路、彩灯驱动电路、直流电源和加/减计数控制电路几个功能模块进行仿真分析。事实证明,Multisim对于激发电子类及计算机类学生的自主学习兴趣,提高本科生的理论与实践结合能力具有积极的指导和促进作用。  相似文献   

基于SEM的公共图书馆社会经济作用分析     

任美林  杨树成  周良华 《情报探索》2013,(2):54-57

在分析公共图书馆与经济发展、科技发展、图书出版、人民生活之间关系的基础上,建立了一个结构方程模型(SEM),并对中国统计年鉴数据进行实证分析,显示我国公共图书馆有利于促进科技和经济发展,应该采取切实可行的措施促进公共图书馆建设,使公共图书馆在科技发展和经济建设中发挥更大作用。  相似文献   

云龙天池自然保护区土壤分布特点及保护     

苏骅  王平  任宾宾 《保山学院学报》2013,(2):26-30

以位于纵向岭谷区核心区域雪盘山中上部的云龙天池自然保护区为研究对象,通过分析保护区成土环境条件,结合实地考察结果,将保护区土壤类型划分为：红壤、黄棕壤、棕壤、暗棕壤、沼泽土、亚高山草甸土（黑毡土）、紫色土7个土类,分析保护区土壤分布规律及土壤发育特点,针对土壤资源发展现状及存在问题,提出土壤资源保护对策。  相似文献   

激励的错位:大学生农民工现象的社会危害性     

孙爱真  任一超  周紫林 《保山学院学报》2013,32(3):70-73

大学生农民工现象是我国当前大学生就业严峻形势的典型写照,真实反映了一部分弱势大学生的职业身份。基于期望与公平理论,从激励的角度出发,分析了大学生农民工现象及其危害性,提出了弘扬积极的社会风气、创造平等参与的机会、加强制度建设等解决方案。  相似文献   

Acute intraocular pressure changes during isometric exercise and recovery: The influence of exercise type and intensity,and participant´s sex     

Jesús Vera  Beatriz García-Durán  Alejandro Pérez-Castilla  Beatriz Redondo  Gabriel Delgado 《Journal of sports sciences》2013,31(19):2213-2219

ABSTRACT

We assessed the intraocular pressure (IOP) behaviour during a 1-minute period of isometric physical effort and the immediate 1-minute of recovery in the mid-thigh clean pull and squat exercises at three different intensities. Twenty physically active individuals performed the isometric mid-thigh clean pull and squat exercises at three intensities (0% [low-intensity], 25% [medium-intensity] and 50% [high-intensity] of the maximum isometric force). IOP was semi-continuously measured by rebound tonometry. There was a statistically significant effect of exercise intensity on IOP (p < 0.001, ?_p² = 0.416), observing that IOP increments were positively associated with exercise intensity. The mid-thigh clean pull and squat exercises did not demonstrate differences (p = 0.510), and also, no differences were observed between men and women (p = 0.683). The IOP changes during the isometric physical effort showed a positive linear behaviour in all conditions (r = 0.70 to 0.96). IOP returned to baseline levels after 8 seconds of recovery. Our data showed a progressive and instantaneous IOP increment during isometric exercise, which was positively associated with exercise intensity. IOP changes were independent on the type of exercise and participant´s sex. After exercise, IOP rapidly (≈ 8 seconds) returned to baseline levels.  相似文献   

Physical demands of elite basketball during an official U18 international tournament     

Jairo Vázquez-Guerrero  Ben Jones  Bruno Fernández-Valdés  Gerard Moras  Xavi Reche  Jaime Sampaio 《Journal of sports sciences》2013,31(22):2530-2537

ABSTRACT

The aims of this study were (a) to compare players’ physical demands between different playing positions in elite U18 basketball games and (b) to identify different clusters of performance. Data were collected from 94 male subjects (age: 17.4 ± 0.7 years), competing in a Euroleague Basketball Tournament. Guards covered a greater relative distance than centres and forwards (small to moderate effect). Forwards and guards had more peak accelerations, high accelerations and high decelerations than centres (moderate to large effects). A cluster analysis allowed to classify all cases into three different groups (Lower, Medium and Higher activity demands), containing 37.4%, 52.8% and 9.8% of the cases, respectively. The high accelerations, high decelerations, peak accelerations and total distance covered were the variables that most contributed to classify the players into the new groups. The percentage of cases distributed in the clusters according to playing position, game type (worst vs worst, mixed opposition, best vs best) and team were different. Centres have lower physical demands specially related with the number of accelerations and decelerations at high intensity and the peak acceleration when compared with guards. Each team has a different activity profile, that does not seem to influence the tournament outcome.  相似文献   

Relationships between cardiorespiratory fitness,inhibition, and math fluency: A cluster analysis     

Juan L. Núñez  Luis Mahbubani  Elisa Huéscar 《Journal of sports sciences》2013,31(23):2660-2666

ABSTRACT

This study identified clusters of adolescents who share similar cardiorespiratory fitness levels and analysed the relationships between cardiorespiratory fitness, inhibition, and math fluency in each of the clusters. The subjects were 490 high-school students aged 10–16 years. The mean age was 13.82 years (SD = 1.12). Latent class analysis identified three clusters with high, medium, and low levels of cardiorespiratory fitness. The high-fitness cluster achieved higher scores in inhibition and math fluency than the low-fitness cluster. Path analysis revealed that the influence of cardiorespiratory fitness on inhibition was non-existent in the three clusters. The effect of inhibition on math fluency was positive and significant in all three cardiorespiratory fitness levels. Cardiorespiratory fitness had a direct, positive, and significant effect on math fluency only in the high-fitness cluster. Therefore, a high level of cardiorespiratory fitness is a significant determining factor in the explanation of math fluency. These results indicate that inhibition does not mediate the relationship between cardiorespiratory fitness and math fluency. However, the benefits of cardiorespiratory fitness affect math fluency, which has important implications for the educational environment and the teaching/learning process.  相似文献