AN EXPERIMENTAL STUDY OF THE ASEISMATIC BEHAVIOUR OF WIDE-SHALLOW COUPLING BEAMS

This paper presents the experimental results of 9 specimens.The mainobject of this experiment is to study the aseismatic behaiour of wide-shallowcoupling beams.Several variables that exert main influence on the behaviourare considered.Also,some aspects concerning the specific design are proposed.     

Height,competition and yield potential in winter wheat

Summary A monogenic dominant male sterility is used for hybrid production in autumn and winter cauliflower. The ratio of male sterile plants in the backcross progenies of autumn cauliflower was 1:1 over five years (1987–1991). However, a significant deficit of male sterile plants was observed in the winter type over the same period.The influence of the temperature on the male sterile phenotype was studied within backcross progenies planted inside polythene tunnels. Six classes of phenotype were defined during the flowering period (from May to November). At low temperature, some male sterile plants developed partial to complete male fertility, whereas at high temperature, male fertile plants became male sterile.Segregation among the progenies of self-pollinated unstable male sterile plants did not deviate from the expected 3:1 ratio. Plants homozygous for the male sterility allele have been revealed by test crosses with a male fertile plant.For use in seed production, stable male sterile plants are vegetatively maintained; however, crossing lines isogenic except at the MS locus would allow male sterile plants to be raised from seed.     

不同基因型油菜锌效率机理Ⅰ ——耐低锌油菜基因型苗期筛选指标研究

采用营养液培养试验比较了低锌营养下芥菜、白菜、甘蓝型3个油菜(Brassica napus L.)品种幼苗的生物量，抗氧化酶活性，根系活力，叶绿素含量及对锌的吸收、利用差异。试验结果表明，3个油菜品种由于基因型不同，在耐低锌营养能力方面存在显著性差异。在低锌时(10-6mol/L Zn2+)，幼苗植株地上部干重以芥菜型>甘蓝型>白菜型，地上部干重分别较无锌对照处理增加17.8%(芥菜型)、9.9%(白菜型)、3.3%(甘蓝型)。芥菜型叶CAT、POD、SOD活性，叶绿素含量及根系活力也明显高于甘蓝型和白菜型油菜。锌积累量及锌利用率也以芥菜型远远大于其它2个品种，锌素利用效率分别为12.3%（芥菜型），8.0%(白菜型)，4.9% (甘蓝型)。苗期油菜叶CAT、POD、SOD等抗氧化酶活性、叶绿素含量及根系活力可以作为筛选耐低锌营养油菜基因型的评价指标之一。     

不同商品化处理及保鲜膜包装对芦蒿冷藏效果的研究

芦蒿是以嫩茎供食的蔬菜。本试验以青杆型芦蒿为材料,研究带叶、去叶、鲜切三种商品化处理方式及0.02、0.05 mm厚度的PE膜、微孔膜三种保鲜膜包装对其(2±0.5)℃冷藏保鲜效果的影响。结果表明,去叶处理在减少VC等营养物质损耗、延缓采后纤维化及维持感官品质等方面优于带叶和鲜切处理;同时芦蒿具有较好的CO2耐受性,用厚度0.05 mm PE膜包装的保鲜效果优于另外两种保鲜膜包装。     

轴流风机通风降温试验

在现有通风系统的基础上，六个风道内各安装一台活动式可拆卸轴流风机，冬季启动风机进行通风，取得了良好的通风降温效果，达到了通风降温目的，且通风均匀，能耗低，减轻了操作劳动强度。并且拆卸方便，不影响风道密闭隔热。     

Variation in dormancy duration of the U.K. wheat cultivar Hornet due to environmental conditions during grain development

Dormancy of wheat grains, the property conferring sprouting resistance, is affected by environmental conditions experienced during grain development. We investigated the hypothesis that short dormancy duration in U.K. wheat grain (thus a high risk of post-maturity sprouting) is related to weather conditions, i.e. high temperatures during grain development. Four wheat varieties were grown at four sites ranging from the far south to the far north of the country in the years 1995–1997,ensuring different temperature and rainfall conditions during grain development. This paper focuses on one variety, Hornet, which has a high sprouting resistance rating. Other varieties gave similar results. Serial laboratory germination tests (seven days, 20°C) at 100°C-dayintervals were used to measure dormancy duration, which was assessed from logistic curves fitted to the data. During the experiment the mean temperatures during grain development differed by over4°C, due to the site × year effect. Significant effects (p>0.05) of site and year (i.e. weather) on dormancy were found, when definitions of dormancy duration of D_A (number of days from anthesis to 50% germination in seven days at 20°C) or D_P (number of days from physiological maturity at 45% grain moisture to 50% germination) were used. Dormancy was markedly shorter in the hot, dry year 1995 compared to the cooler, wetter years 1996 and 1997. A relationship, as postulated by Belderok, between accumulated temperature during the dough stage of grain filling and dormancy duration was not found. However, a relationship of dormancy duration to the mean temperature during grain development was found, with short dormancy periods occurring after high mean temperatures were experienced. This revised version was published online in August 2006 with corrections to the Cover Date.     

Analysis for Heat Transfer in Micro-annular Channel with Unsymmetrically Heated Walls in Slip Flow Regime

A theoretical analysis is presented for heat transfer in micro-annular channel with an adiabatic wall and a heated wall with uniform wall temperature in slip flow regime. The energy equations with the boundary conditions of temperature jump are solved for the hydrodynamical and thermal fully developed laminar flow of the incompressible fluid in this microchannel. The influences of the Kn number, the ratio of inner diameter to outer diameter on the heat transfer characteristics are discussed respectively. The results show that the Nusselt number in microchannel decreases with the increasing of Kn number comparing with that in macrochannel.     

储藏条件对水稻种子发芽活性影响的研究

文章讨论了储藏中水稻种子的水分含量、储藏温度和气体条件（如ＣＯ２气体、脱氧剂等）对水稻处子发芽活性的影响。     

Screening for low grain cadmium phenotypes in sunflower, durum wheat and flax

Cadmium (Cd) level in nonoilseed sunflower (Helianthus annuus L.), flax (Linum usitatissimum L.), and durum wheat (Triticum turgidum L. var. durum) grown on uncontaminated, alkaline soils has exceeded limits established in Northern Europe. Separate field experiments were conducted to investigate variability of grain Cd levels among sunflower, durum wheat and flax germplasm, and to seek an efficient screening method for future breeding. There were large variations in leaf Cd concentration among 200 sunflower lines. These lines performed more consistently for Cd uptake at the R5 stage than at the V8 stage across 4 locations with markedly differing soils. Cd concentration in V8 leaves was not related to Cd in grain. The positive correlation between R5 leaf Cd and kernel Cd level was obtained from nonoilseed hybrid (Sigco 954) (R²; = 0.74**), and 200 lines (R² = 0.44**) tested over 4 locations in 2 field trials, respectively. This indicates that an efficient and low cost screening method can be developed for genotype selection, but plants must be grown to the R5 stage. A preliminary evaluation of 30 durum wheat and 74 flax lines indicated large variations in grain Cd level of durum wheat and flax. Grain Cd concentration ranged from 0.11 to 0.34 mg Cd kg^-1 DW for durum wheat, and 0.14 to 1.37 mg Cd kg^-1 DW for flax, respectively. This variability indicates that breeding for low grain Cd in durum wheat and flax should be feasible. This revised version was published online in July 2006 with corrections to the Cover Date.     

生物防腐剂及其在食品防腐中的应用

随着对食品安全和健康问题的普遍关注,消费者对天然产物的兴趣越来越高。由于化学防腐剂存在的问题和缺陷,天然生物防腐剂引起了食品工业界的极大重视。采用天然防腐剂,可以赋予食品更高的营养价值,减少或完全停用化学防腐剂,并且确保食品的微生物安全性。天然生物防腐剂是指来源于植物、动物、微生物的具有预防食品腐败作用的抗菌物质。天然防腐剂的作用方式是抑制微生物的生长及发生在食品中的氧化反应和酶促反应。本文综述天然生物防腐剂的种类、抑菌机理及其在食品防腐中的应用研究现状,阐述在栅栏技术中的应用效果,展望天然生物防腐剂今后的应用前景及其在开发应用中需要研究解决的主要问题。