Microcracking and Chloride Penetration of Concrete under Uniaxial Compression

A non-destructive method of evaluation of specific crack area was used to characterise microcracking in concrete prisms during uniaxial compression loading and unloading. Chloride profiles were also measured after the same concretes were exposed to chloride environment. The relation among microcracking, stress-strength ratio and chloride penetration of concrete were analysed based on the experimental results. Under compressive load, the apparent chloride diffusion coefficient decreases until about one third of the ultimate load. Further increase of compressive load improves the chloride diffusion coefficient again. There is a close link between microcracking and stress-strength ratio. The index of specific crack area can be used to indicate the microcracking and study chloride transport behaviour into concrete under the influence of microcracking.     

Shear resistant performance of RC columns subjected to vertical near-fault velocity pulse-like earthquake actions

The aim is to evaluate the seismic properties of ancient timber structure after strengthening and analyze the failure process and corresponding failure state. Based on the hysteretic behavior and energy dissipation principle of the dovetail column-frame strengthened with CFRP and Arches Brackets under the low reversed cyclic loading, the “potential of destruction-resisting” of the two energy-consuming components is obtained. The dissipated energy of each energy-consuming component under the various earthquake conditions is calculated combining with the shaking table test of ancient timber structure. The model of seismic damage evaluation of the two energy-consuming components is established on the basis of the “potential of destruction-resisting” and the dissipated energy. By means of the energy distribution coefficient, the relationship of the failure state between energy-consuming components and overall strengthened structure is discovered, and the model of seismic damage evaluation of the overall structure under the various earthquake conditions is presented. With the derived model of seismic damage evaluation, the failure coefficient of the energy-consuming components and the overall strengthened structure is quantitatively calculated. According to the failure state, the corresponding damage grade of overall strengthened structure is obtained. The results can provide a reliable theoretical basis for predicting the destruction before earthquake and re-reinforcement to the strengthened ancient timber structures after earthquake.     

Genetic linkage map of Chinese native variety faba bean (Vicia faba L.) based on simple sequence repeat markers

Simple sequence repeat (SSR) marker is a powerful tool for construction of genetic linkage map which can be applied for quantitative trait loci (QTL) and marker‐assisted selection (MAS). In this study, a genetic map of faba bean was constructed with SSR markers using a 129 F₂ individuals population derived from the cross of Chinese native variety 91825 (large seed) and K1563 (small seed). By screening 11 551 SSR primers between two parents, 149 primer pairs were detected polymorphic and used for F₂ population analysis. This SSR‐based genetic linkage map consisted of 15 linkage groups with 128 SSR. The map encompassed 1587 cM with an average genetic distance of 12.4 cM. The genetic map generated in this study will be beneficial for genetic studies of faba bean for identification of marker‐locus‐trait associations as well as comparative mapping among faba bean, pea and grasspea.     

Analysis on drag coefficients of bundled conductors under wind load

Drag coefficients of quad-bundled conductor under different wind speeds and attack angles are firstly determined by means of wind tunnel test. Meanwhile, the drag coefficients are obtained by numerical simulation method and the results are consistent with those by the wind tunnel test. Furthermore, cross flows around six-bundled and eight-bundled conductors are numerically investigated, and the drag coefficients are then determined. Compared with the determination method of wind load on conductor in current Chinese code and the IEC code for the design of transmission line, the drag coefficients defined in the Chinese code may be too large for bundled conductors, and may need to be adjusted based on further theoretical and wind tunnel test investigation.     

以“新工科”建设为导向的“食品生物化学”课程PBL教学模式的探索

为培养创新型、实践型人才,实现驱动创新型中国发展,以“新工科”建设为导向,对食品专业课程“食品生物化学”进行PBL教学实践。针对教学中存在的问题,分别从教学内容、教学过程、考核方式等方面进行改革和探索,构建以提升学生能力为培养目标的教学体系,提升教学质量,满足社会发展对人才的需要。实践证明,PBL教学能有效地促进学生学习的自主性,提高学生的实践创新能力、交流能力,培养团队互作精神,具有重要的现实意义。     

灌浆初期低温对春玉米产量构成的影响研究

旨在研究东北地区低温冷害对春玉米灌浆的影响,确定春玉米灌浆期间冷害影响农业气象指标。用人工气候室通过模拟自然低温（平均15℃、17℃、19℃）方法,对灌浆初期盆栽春玉米进行（3、5、7天）胁迫处理。结果表明：春玉米在灌浆初期经不同天数的低温处理后,穗粒数减少,穗粒重、百粒重和叶绿素降低,成熟期延迟,果穗秃尖长度和籽粒含水量增加,作物产量呈不同程度的下降。温度越低,持续时间越长,对玉米产量的影响越严重。其中在15℃低温下处理7天后,玉米产量下降最大,较对照穗粒重减少了32.4%,百粒重减少9.2%。可见,灌浆初期低温对春玉米产量结构影响最大的因素是结实率和籽粒干物质含量的双重降低。     

性信息素技术在高粱鳞翅目害虫发生动态监测中的应用

为研究高粱鳞翅目害虫发生动态,解决防治适期问题,通过3年田间试验,利用性诱技术诱集鳞翅目害虫,探索黏虫、条螟、玉米螟、桃蛀螟、草地贪夜蛾和二化螟的发生动态。研究发现,玉米螟和条螟发生最为严重,占鳞翅目害虫数的70%以上,各类鳞翅目害虫的发生时段在5月初—8月初,其中主要集中在5月底—7月中下旬大量发生。研究结果可为更加科学合理预测高粱鳞翅目害虫的发生危害提供依据,也为本地有机高粱生产过程中的鳞翅目害虫制定防控方法提供实践基础。     

药用植物水飞蓟的研究进展

水飞蓟的主要活性成分是黄酮类化合物水飞蓟素,能抑制损伤、抗肿瘤、治疗心脑血管等疾病,尤其对肝损伤具有很好的疗效。本研究从植物学特性、栽培技术、活性成分和药理作用研究综述了药用植物水飞蓟目前的研究进展。旨在对进一步提升栽培技术、开发水飞蓟的药用价值提供一定的指导和借鉴。研究发现,水飞蓟在非生物胁迫下通过影响次生代谢产物、抗氧化酶活性及渗透调节物质含量等方式来调节植物生长发育。此外,施加外源植物生长激素能抵抗外来胁迫并且能促进其生长发育。适度的干旱、盐碱等非生物胁迫,有助于提高水飞蓟中活性成分含量的积累。     

不同抗旱措施对‘东试早’柚产量及品质的影响

为解决西双版纳季节性干旱对‘东试早’柚开花结果的影响,以10 年生‘东试早’柚为试材,采用随机区组试验设计,连续2 年开展黑地膜覆盖、白地膜覆盖、杂草覆盖、添加保水剂和常规管理措施的田间比较试验,研究不同抗旱措施对柚子园土壤容重、营养和产量及品质的影响。结果表明,覆草处理下不同土层土壤容重最小,孔隙度最大,而覆盖薄膜后土壤容重最大,孔隙度最小。不同处理土壤营养元素含量随时间变化差异较大,覆盖处理均能增加土壤铁、锌元素含量,而覆草处理更能增加土壤表层大量元素及钙、硼等元素含量,保水剂处理能减缓中微量养分下降的趋势。各抗旱措施处理均能提高坐果率和产量,其中以黑膜处理的坐果率和产量较对照增加最为显著,比对照分别提高了91.7%和56.9%。覆盖处理对单果重及可食率影响显著,进而影响可溶性固形物、总酸、总糖和还原糖,而对果形指数、囊瓣数量及种子数影响不显著,其中覆草能显著提高总糖、Vc 及可溶性固形物的含量,分别比对照提高18.7%、18.2%和11%。     

普通小麦HMW-GS Dx5与Dx2亚基共显性标记

高分子量麦谷蛋白是决定小麦烘烤品质的重要蛋白组分,其中Glu-D1基因座(Locus)与小麦的烘烤品质关系最为密切,该座位的亚基类型中,Dx5亚基的面团弹性要大于Dx2亚基。本研究根据Dx5亚基和Dx2亚基DNA序列的中间重复区重复单元数目的不同,开发出用于鉴别两种不同亚基类型的共显性标记,并利用该标记对含有Dx2亚基的川麦38与具有Dx5亚基的川麦42杂交F1植株、F2群体进行PCR分析。研究结果显示电泳条带清晰,片段大小符合期望值,F2群体检测统计结果符合孟德尔定律。研究结果表明该共显性标记能够用于早期分子辅助选择育种。