孔隙结构图像分析中不同试验因素对分析结果的影响

研究了不同试验因素 (包括图像分辨率、土壤切片定向性、分析区域大小等 )对孔隙结构图像分析结果的影响以及试验误差 ,并简要介绍了用于分析土壤孔隙结构的土壤切片及数字图像的制备技术。结果表明 :不同试验因素对分析结果均会产生一定的影响 ,试验误差约在 1 0 %。这表明同一研究中应保持试验条件的相对一致以保证分析结果的可靠性和可比性     

淹水程度对滩地枫杨木材化学性质的影响

通过研究淹水程度对滩地枫杨木材化学性质的影响 ,以期全面了解滩地主要造林树种的化学性质 ,提出合理的定向培育技术及进一步综合利用措施 .研究结果表明 :滩地枫杨木材的 p H值均小于 6.5 ,属于酸性木材 ,第一、二组木材的 p H值分别为 5 .41和 5 .0 0 ,在 0 .0 5水平上差异显著 .除碱性缓冲容量外 ,第二组木材的酸性缓冲容量、总缓冲容量以及每降低 1p H值消耗的 HC1量均比第一组高 .淹水程度对滩地枫杨木材纤素含量几乎无影响 ,其值均为 45 .2 %左右 ;但第一、二组的半纤维素分别为 14 .0 4%和19.5 0 % ,增加了 3 8.9% ;第一、二组的木质素含量分别为 19.9%和 2 0 .6% ,增加了 3 .5 % .     

大豆低聚糖分离纯化研究

大豆低聚糖能促进人体肠道内固有的有益细菌——双歧杆菌的增殖,从而抑制肠内腐败菌的生长,并减少有毒发酵产物的形成。是一类功能性低聚糖。综合论述了国内外工业上分离纯化大豆低聚糖的典型工艺过程,并对各单元操作中所用方法进行了比较和分析。     

盐碱胁迫下植物生理和钙信号通路分子机制的研究进展

土壤的盐化和碱化往往伴随发生,在盐碱胁迫下,植物会遭受许多类型的非生物胁迫,严重影响植物的正常生长发育.本综述首先介绍了盐碱土的分类;其次从四个方面对植物在盐碱胁迫下体内产生相应生理机制进行详细介绍;接下来以植物在盐碱胁迫下产生的钙信号为重点进行阐述,包括植物首个非离子通道型盐胁迫下离子感受器GIPCs的发现、盐碱胁迫...     

我国机械化移栽自动分苗取苗技术研究现状

由于自动分苗取苗技术的限制,全自动移栽机发展缓慢,现有机具造价高、通用性差,无法满足我国的实际需求,难以大规模推广应用.为此,首先,介绍了目前国内钵苗与裸苗自动分苗取苗技术发展状况,按照分苗取苗方式的不同,将钵苗自动取苗装置分为顶杆式、夹取式、气力式、组合式和链带式等,将裸苗自动分苗取苗装置分为链带式、外槽轮式、气力式...     

清代归化城土默特地区的移民过程考探

通过对清代归化城土默特地区移民过程的研究,证明该地区移民是多种因素造成的,但清廷边疆政策一直主导移民过程。对清代归化城土默特地区的移民过程进行了考探,以期为研究其他地区移民带来参考借鉴。     

我国热带天然林植被C贮存量的估算

以海南岛尖峰岭热带林生态系统定位研究站多年的研究作为基本数据,用两种方法计算了海南岛和用一种方法计算了云南南部热带森林的Ｃ素库总量。结果表明,海南热带天然林的Ｃ素库总量为０．７１９－０．７３４亿ｔ,云南南部的热带天然林的Ｃ素库总量在０．６５３亿ｔ以上。     

Safety Assessment of Circular Arches Tunnel Evacuation on Surrounding Geotechnical Environment

Based on the stochastic medium theory, influence on the surrounding rock and soil by tunnel excavation was studied. formula for predicting movement and deformation of rock and soil mass caused by tunnelling were deduced. And especially for the tunnel with circular arch section, half analytic solution for this problem was put forward. Furthermore, a program was developed to compute the movement and deformation of the rock and soil mass resulted from excavation. The deformation failure criterion of stochastic medium for estimating the surroundings safety was provided and was applied in an engineering example, which proved that the results of the research were reasonable and significant for the tunnel safety construction.     

A new freeze-dried living virus vaccine against sheep-pox

A sheep-pox virus strain has been adapted and multiplied in primary lamb kidney cell cultures. The main characteristics of the strain have been verified in vitro after clones were isolated, and the results confirmed its identity. The safety and the potency of the strain have been investigated in sheep.

The inoculation of the strain to sheep was followed by a post-vaccinal reaction materialised by a nodule at the site of inoculation and an increase of temperature by about 1°C. No reactions adversely affecting pregnancy have been noted. Immunisation was demonstrated by an increase in the level of neutralising serous antibodies and protection against the pathogenic virus. The immunity tended to decrease during the second year after primovaccination and a yearly booster vaccination appeared to be necessary. Primovaccination of lambs over 2 months of age produced a better immunity, especially when the lambs were born from vaccinated ewes.

This strain forms the active principle of a freeze-dried vaccine containing no adjuvant of the immunity.     

一种水肥气高效耦合灌溉系统的设计与试验研究

本研究旨在解决传统灌溉农业的“水氧矛盾”和根系的“向水追氧”两大农业难题,应用现代水肥耦合和增氧灌溉技术,设计了一种水肥气高效耦合灌溉系统。通过应用灌溉系统对水稻、黄瓜等作物的栽培试验证明：相比于常规灌溉方式,水、肥、气耦合灌溉能促进作物根系生长和提高根系活力,使其能最大限度地从土壤中吸收水分和养分,进一步挖掘和提高作物自身生产力,提高水肥利用效率,增产提质,同时也为从根源上缓解农业面源污染提供一种新途径。