番茄裂果与果皮结构的关系及其杂种优势表现

以4份抗裂番茄为母本,3份易裂番茄和1份抗裂番茄为父本,按照不完全双列杂交设计配制4×4的杂交组合,研究8个亲本和16个F1的裂果特性与果皮结构的关系,分析它们的杂种优势表现.结果表明,易裂基因型的果皮较薄,抗裂基因型的果皮普遍较厚,但也有果皮薄而抗裂能力强的基因型.裂果特性有明显的杂种优势,优势的方向在不同组合间有很大的差异.亲本的一般配合力对杂种后代的抗裂时间发挥了决定性作用.对利用结构特征改良番茄抗裂能力的潜力进行了讨论.     

水泥砼路面板底脱空对沥青加铺层反射裂缝的影响分析

采用三维有限元分析方法，计算分析了具有接缝的旧水泥混凝上路面上沥青加铺层在行车简载作用下应力随板底脱空的变化情况，从理论上深入研究了不同板底脱空对沥青加铺层反射裂缝的影响，阐述了板底脱空对沥青加铺层荷载应力的影响。     

Desiccation and cracking behaviour of clay layer from slurry state under wetting-drying cycles

Laboratory tests were conducted to investigate the effect of wetting-drying (W-D) cycles on the initiation and evolution of cracks in clay layer. Four identical slurry specimens were prepared and subjected to five subsequent W-D cycles. The water evaporation, surface cracks evolution and structure evolution during the W-D cycles were monitored. The effect of W-D cycles on the geometric characteristics of crack patterns was analyzed by image processing. The results show that the desiccation and cracking behaviour was significantly affected by the applied W-D cycles: the measured cracking water content θ_c, surface crack ratio R_sc and final thickness h_f of the specimen increased significantly in the first three W-D cycles and then tended to reach equilibrium; the formed crack patterns after the second W-D cycle were more irregular than that after the first W-D cycle; the increase of surface cracks was accompanied by the decrease of pore volume shrinkage during drying. In addition, it was found that the applied W-D cycles resulted in significant rearrangement of specimen structure: the initially homogeneous and non-aggregated structure was converted to a clear aggregated-structure with obvious inter-aggregate pores after the second W-D cycle; the specimen volume generally increased with increasing cycles due to the aggregation and increased porosity. The image analysis results show that the geometric characteristics of crack pattern were significantly influenced by the W-D cycles, but this influence was reduced after the third cycle. This is consistent with the observations over the experiment, and indicates that the image processing can be used for quantitatively analyzing the W-D cycle dependence of clay desiccation cracking behaviour.     

土壤裂缝产生过程中双氢胺对氮溶质运移的影响

模拟稻田土壤在淹水后加入不同量的（NH4）2SO4和双氢胺（DCD）抑制剂的溶液，让土壤自然变干，直至土壤产生裂缝到裂缝稳定的连续培养，在培养第10d后再给土柱复水的6种处理，每天监测各处理渗漏液中铵态氮、硝态氮和亚硝态氮的浓度变化。试验结果表明，肥料（NH4）2SO4和DCD的加入量是10：1．5和10：2时，即DCD和肥料（NH4）2SO4施用量的高比例能在裂缝产生过程时较好地抑制铵态氮硝化。整个培养过程没有获得DCD抑制剂对渗漏液中硝态氮和亚硝态氮的影响。裂缝稳定后的复水对渗漏液中的铵态氮没有影响，但是提高了渗漏液中的亚硝态氮和硝态氮的浓度。     

蛋壳破损自动检测模型研究

为了建立蛋壳破损检测模型，试验采用敲蛋装置与声检测控制器组成的计算机蛋破损检测系统获取被检蛋声音信号数据。通过对蛋声音信号的功率谱分析而得到反映蛋壳破损特征的参数：功率谱面积的平均值x₁，最大功率谱面积与最小功率谱面积的差值x₂，X轴方向上质心的平均值x₃，X轴方向上质心最大值与其最小值的差x₄，Y轴方向上质心的平均值x₅，Y轴方向上质心最大值与其最小值的差x₆，共振峰频率的最大值x₇和共振峰频率的最大值与其最小值间的差值x₈；再通过Bayes原理建立与蛋壳破损特征参数相关的蛋壳破损模型。检验结果表明模型准确率达到92%。     

包装对龙眼果实贮藏期间果皮失水褐变和细胞超微结构的影响

研究了(10±1)℃和50%相对湿度贮藏条件下无包装和0.015 mm厚的聚乙烯薄膜袋密封包装的“福眼”龙眼果实果皮失水、果皮褐变和细胞超微结构变化。结果表明，无包装的龙眼果实采后极易失水导致果皮迅速褐变，且褐变随贮藏时间的延长和果皮失水率的增加而升高，果皮褐变指数与果皮失水率呈极显著正相关(P<0.01)。在龙眼果皮失水褐变过程中，果皮细胞的细胞器和膜系统的完整性受到严重的破坏。而聚乙烯薄膜袋密封包装则显著减少了果皮失水和抑制果皮褐变，并保持较好的果皮细胞的细胞器和膜系统的完整性。据此认为，聚乙烯薄膜袋密封包装抑制龙眼果实失水果皮褐变与其维持细胞器和细胞膜的完整性有联系。     

黄土旱塬农业生态系统土壤深层水分消耗与水分生态环境效应

研究了渭北旱塬不同土地利用方式下大田土壤深层剖面含水率的变化特征，并与长期田间定位试验结果进行比较。结果发现，不同土地利用方式能显著影响土壤深层含水率状况，各种方式对土壤深层水消耗能力的排序是15龄苹果园＞15龄人工苜蓿＞10龄苹果园＞刺槐幼林＞高产农田＞20年撂荒地＞5龄苹果园＞裸地。10龄苹果园剖面剩余含水率分布接近高产农田，而15龄苹果园土壤剩余含水率低于高产农田，说明10龄到15龄苹果树耗水量显著增大，超过高产农田作物消耗的水分，导致土壤深层水分进一步消耗。由于塬面大部分耕地是高产农田与苹果园，土壤深层含水率普遍处于较低水平。苹果树的大面积种植加快了土壤深层水分消耗，最终可能影响这一区域的陆地水循环。     

ANALYSES FOR DEFECTS OF 18G_2ANb STEEL SPHERICAL TANKS OF NATURAL GAS

Calculations and analyses are made with the CVDA, IIW, JWES standards for the strength and welding defects of two spherical tanks of natural gas in CHONG QING. The results of the analyses indecate that though there are some problems with the welding quality in these tanks, they may still be used with the desingned presure. Now the formal working of these two spherical thanks has verified of the validity the calculations and analyses.