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1.
Abstract. In field and laboratory experiments the conditioner‘Agri-SC’has shown improvements in the structure of loamy sand soils in east Shropshire, UK. It resulted in statistically significant decreases in soil bulk density values and increases in soil porosity and aggregate stability. Further experiments are in progress on both loamy sand and silt loam soils.  相似文献   
2.
The purpose of this study was to compare responsiveness to environment as well as the stability of newly developed promising lines with traditional commercial cultivars. Subject research was conducted in Ankara between 1983-1989 on common and durum wheat cultivars and lines. Regression coefficient (b) was used as the criterion of genotypes' responsiveness to environment whereas deviation from regression (S2d) and coefficient of determination (r2) were used as stability parameters. Each experiment year was regarded as an environment and yield average of each year was used as the environmental index.
In consequence of the research, it was determined that new varieties with high yield, adaptable to diverse environments could be developed by means of hybridizations between parents having different genetic characteristics which were provided from diverse ecological regions.  相似文献   
3.
为测定不同氮肥施用量对黑土团聚体组成及稳定性、有机碳含量及团聚体有机碳分布的影响,阐明黑土有机碳稳定性对不同施氮水平的响应机制,本研究在吉林省梨树县不同施氮水平长期定位试验田进行取样,以施氮水平不同设置5个处理,分别为T1(0)、T2(160 kg·hm-2)、T3(240 kg·hm-2)、T4(280 kg·hm-2)、T5(320 kg·hm-2),分析长期不同施氮量下水稳性团聚体组成、团聚体结构特征、土壤总有机碳含量及团聚体有机碳分布的变化,探究酸化黑土有机碳含量影响特征。结果表明:随氮肥施用水平的升高,土壤碱解氮(AN)和全氮(TN)含量先增后减,T3处理含量最高,AN和TN分别比T1处理高24.90%、10.28%;土壤速效磷(AP)的含量呈下降趋势。随氮肥用量的提高,土壤团聚体呈现大粒径团聚体向小粒径团聚体转变的趋势,>2 mm粒径团聚体下降14.55%。土壤有机碳总量随施氮水平的提高呈先增后减的趋势,施氮量为280 kg·hm-2有机碳含量最高;>2...  相似文献   
4.
修正车辆理想制动力分配曲线使之适用于装用电涡流缓速器的车辆,对装用电涡流缓速器的车辆制动稳定性进行了定性分析,并且提出了增加前后制动器制动力的分配系数来提高装用缓速器后的车辆制动稳定性的技术措施.对给定参数的车辆的定量分析表明,提出的技术措施能扩大车辆同步附着系数的范围,降低车辆后轮先抱死的可能性,提高车辆的制动稳定性.  相似文献   
5.
Summary Results from a cooperative breeding programme with timothy for the northern areas of Scandinavia are presented. The main aim of the programme was to identify genotypes for synthetic populations that are high yielding, adapted over the whole area and stable over years. A polycross comprising 12 genotypes from each of five sites within the region was formed. The subsequent 60 half-sib families and four reference varieties were then compared under sward conditions at the same sites. The trials lasted for three years and results for total dry matter yields are presented.Significant differences in yield between lines were found. There were also significant two and three factor interactions between lines, sites and years. A new two-step procedure is presented to select the genotypes to make up a synthetic variety. Firstly, a superiority measure (Q-value) is used to select a group of genotypes that are high yielding and stable over sites and years. Secondly, the GxE part of the Q-value is split into two terms. One measures adaptation to predictable environmental conditions. The other one measures stability to unpredictable changes in the environment. A plot of these two measures provides a tool for discarding unstable or poorly adapted genotypes. The statistical properties of the selection parameters are discussed.  相似文献   
6.
利用干拌法制作橡胶粉改性沥青混合料,将搅拌好的沥青混合热料在搅拌锅中进行闷料处理,温度恒温在165℃,分别闷至0 min、15 min、30 min、45 min、60 min,用每个时间段的沥青混合料制成试验用的试件进行高温稳定性分析,结果表明,在闷料开始阶段,橡胶粉改性沥青混合料的稳定度随闷料时间的增加逐渐提高,当闷料时间为15 min左右时,混合料的稳定性达到最大值,随后,稳定性逐渐下降。  相似文献   
7.
通过两个试验,研究在体外模拟瘤胃发酵条件下N-乙酰-DL-蛋氨酸的降解率。试验1:N-乙酰-DL-蛋氨酸在pH值6.5、温度为39℃的缓冲液中孵育9h,其降解率为3.3%。试验2:运用瘤胃体外发酵技术研究N-乙酰-DL-蛋氨酸不同添加量对pH值、氨态氮、微生物蛋白动态变化的影响。结果表明,添加0.4、0.6gN-乙酰-DL-蛋氨酸发酵3~6h,均能够显著降低体系的pH值;添加0.6gN-乙酰-DL-蛋氨酸发酵12h能够显著提高氨态氮的浓度;N-乙酰-DL-蛋氨酸在发酵过程中不影响微生物蛋白产量。以上结果显示,N-乙酰-DL-蛋氨酸在体外模拟瘤胃发酵的条件下可以稳定存在。  相似文献   
8.
Postural stability maintains balance, protects the spinal column, and allows accurate responses to destabilizing forces. The musculus multifidus (m. multifidus) is the major postural muscle located adjacent to the vertebrae along the length of the spinal column. Increased cross-sectional area (CSA) of the m. multifidus has been demonstrated in horses after a rehabilitation strengthening exercise program; however, correlation with functional postural stability has not been shown. The objective of the present study is to evaluate the relationship of the thoracolumbar m. multifidus CSA and measures of postural sway performance in lame horses undergoing rehabilitation exercises in clinical cases. Seven client-owned horses admitted to the equine rehabilitation service were included in the study. M. multifidus CSA was measured via ultrasonography at the start of a rehabilitation program (initial evaluation) and after 12 weeks of rehabilitation exercises (final evaluation). Postural sway data were also measured at initial and final evaluation. A significant increase in m. multifidus CSA was seen from initial to final evaluation. A moderate to strong correlation was present between m. multifidus CSA and postural sway variables. These results suggest that there is an association between postural stability and m. multifidus hypertrophy in lame horses undergoing individualized rehabilitation programs. However, more research is needed to provide a definitive answer on the nature of this relationship. Ideally, specific performance tests would better define and examine the relationship in which to guide clinicians in rehabilitation protocol development.  相似文献   
9.
为提高红霉素发酵单位,考察了二甲基亚砜(DMSO)添加时间和体积分数对红霉素合成的影响,采用筛选自身代谢产物突变株的方法,将突变株进行常压室温等离子体(ARTP)诱变和耐受高浓度DMSO处理。结果显示,在36 h向发酵瓶中添加30000μg/m L红霉素,筛选得到化学效价比对照提高22.4%的菌株。DMSO最适添加时间为发酵48 h,最适添加剂量为0.2%,其可提高发酵单位10.1%。  相似文献   
10.
蛋清粉凝胶性与凝胶稳定性的研究   总被引:1,自引:1,他引:1  
胥伟  迟玉杰  孙强 《中国家禽》2012,34(2):22-24
研究蛋清粉在贮藏期间所成凝胶的质构、持水性以及微观结构的变化。结果显示,蛋清粉的凝胶硬度、弹性、粘结性、持水性分别为346g/cm2、0.905、0.382、52.00%,25℃下贮藏180d后,蛋清粉的凝胶硬度与粘结性较贮藏初期并无显著性变化(P>0.05),而凝胶弹性与持水性与贮藏初期相比差异性显著(P<0.05)。蛋清粉的溶解性随贮藏时间的延长呈下降趋势,但降幅很小,25℃下贮藏180d时与贮藏初期相比无显著性差异(P=0.154)。500倍扫描电镜(SEM)下观察蛋清粉所成凝胶,其结构空隙很大,分布疏松,随贮藏时间的延长无明显变化。研究结果表明,贮藏时间与温度对蛋清粉的溶解性影响很小,而对蛋清粉的凝胶性影响较大,含水量是影响蛋清粉凝胶稳定性的重要因素。  相似文献   
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