考虑损伤时材料的断裂应力

工程结构的损伤分析、寿命预测及材料细观损伤机理与材料的强韧化研究，具有十分重要的工程意义，并具有广阔的发展前景。本文研究考虑损伤时材料的断裂应力，推导出了在表面能密度有限的情况下，损伤断裂应力的计算公式。     

花生硼素营养机理及其施肥研究进展

概述了硼素对花生的营养作用及其吸收、积累机制,硼素缺乏所引起的一系列花生生理病变,硼素营养诊断,硼素与不同营养元素配施对花生的影响及其合理施肥。     

黄土高原旱地苹果高接模式与品种更新技术研究

在黄土高原旱地进行了苹果高接换种技术试验。结果表明,对每公顷栽植1 260株的高密园,宜采用细长纺锤形整形,每公顷栽植834株的中密园宜采用小冠疏层形结构整形;单枝单芽贴干嫁接宜在4月中下旬进行,单芽腹接和地面蹲靠接应提前到3月下旬至4月上旬。细长纺锤形果树宜采用单枝单芽贴干嫁接,单株宜高接11个头,采用单芽腹接宜接12个头,地面蹲靠接以3个头为宜;小冠疏层形嫁接头数以30个较好。嫁接时砧枝截留长度为5～8 cm,嫁接不同枝段芽体接穗以调整平衡树体长势;依据树龄采用不同嫁接方法,1～5年生树选用单芽腹接,5～10年生树采用单芽枝接,11年生以上树宜采用地面蹲靠接;嫁接后采取封闭切口+套塑料袋的效果较好,单芽腹接芽眼包扎1层接树膜效果明显,地面插接及时包严用土培实保护,嫁接成活率平均在93．5％以上。嫁接后同步成形,树体生长旺,树冠恢复能力强,结果早,产量高,该技术已大面积推广应用,效益十分显著。     

数字化测图实践与认识

随着测绘科学技术的发展，传统的模拟法测图方法已被数字化测图方法所替代。本文从数字化测图工作的外业、内业以及测量成果表现形式上，对数字化测图与模拟法测图的特点进行了对比分析；分析了数字化测图质量评价的内容和特点；结合数字化测图的工作实践，对数字化测图工作提出了几点有益的认识。     

采煤废弃物对作物生长的影响

通过室内栽培试验,研究了煤矸石和粉煤灰作为培养基对作物生长的影响。结果表明:(1)粉煤灰物理性质不适于作物生长,对作物长势影响最大,在粉煤灰排放场不覆土直接种植作物不可取;(2)煤矸石和粉煤灰会对作物产生重金属污染,尤其是细颗粒煤矸石的污染最大;(3)充填采煤废弃物复垦应该保证足够的覆土厚度。     

台湾青枣的品种对比试验

对8个南方表现优良的台湾青枣品种在北方设施栽培下进行了对比试验,测定了营养生长、生殖生长及果实品质指标。综合分析表明,最适宜北方大棚栽培的台湾青枣品种是碧云,其次是大蜜、五千种和脆蜜。     

Effects of atorvastatin on expression of PAPP-A induced by TNF-α and IL-1β in rat aortic endothelial cells

AIM: To investigate the effects of atorvastatin on the expression of pregnancy-associated plasma protein A(PAPP-A)induced by TNF-α and IL-1β in endothelial cells. METHODS: The rat aortic endothelial cells were isolated from thoracic aortas and cultured by the tissue explant method. The cells in passage 3-4 were used in the experiment and were randomly divided into 4 groups: blank control group: the cells were treated without any intervention; atorvastatin concentration groups: the cells were incubated with atorvastatin at the concentrations of 0.1, 1 and 10 μmol/L for 24 h; atorvastatin time groups: the cells were incubated with atorvastatin at the concentration of 10 μmol/L for 6 h,12 h and 24 h; atorvastatin+inflammatory factors groups: the cells were pre-incubated with 60 μg/L TNF-α or 20 μg/L IL-1β for 1 h, then different concentrations of atorvastatin (0.1, 1.0, 10 μmol/L) were added for 6 h,12 h and 24 h. MTT reduction assay was used to observe the cell proliferation. The mRNA expression of PAPP-A was detected by RT-PCR. The protein level of PAPP-A in the supernatants of cultured cells was measured by ELISA. RESULTS: Compared with blank control group, no significant change of cell proliferation was observed after the intervention of atorvastatin and TNF-α/IL-1β for 3 h, 6 h, 12 h, 24 h and 48 h, indicating that the drugs had no toxic effects on the cells. No significant difference of PAPP-A expression between atorvastatin groups and blank control groups was found. Compared with TNF-α groups and IL-1β groups, PAPP-A expressions in atorvastatin intervention groups significantly decreased. The protein level of PAPP-A was gradually decreased with the raised concentration of atorvastatin and the prolonged time in a concentration- and time-dependent manner. CONCLUSION: Atorvastatin doesn't influence the PAPP-A expression, but inhibits the expression of PAPP-A activated by inflammatory factors in a concentration- and time-dependent manner in primary cultured rat aortic endothelial cells.     

高校学生干部选拔流程分析——思想政治辅导员选拔学生干部的启示

选拔出德才兼备的学生干部是高校学生工作的重点之一.选拔过程中,做好选拔前期准备工作,注意不同选拔方式的优缺点,录用过程引入试用期制,避免低效率低民主的选用.高校学生干部选拔的方向是民主和高效的统一、科学与艺术的统一.     

4种鱼类肝脏细胞色素P450对毒死蜱、对硫磷及马拉硫磷的脱硫代谢

以毒死蜱、对硫磷及马拉硫磷为供试农药,以斑马鱼、剑尾鱼、麦穗鱼及太阳鱼为供试生物,研究了3种农药对4种鱼的急性毒性,4种鱼肝细胞色素P450对3种农药的脱硫代谢作用及两者之间的相关性。结果表明,毒死蜱对于上述4种鱼的96hLC50分别为1.94、0.171、0.0273、0.0681mg·L^-1;对硫磷为2.6、0.0559、1.78、1.02mg·L^-1;马拉硫磷为7.07、0.907、6.03、0.172mg·L^-1。4种鱼肝脏P450对于毒死蜱代谢的Vmax/Km值分别为1.67×10^4、2×10^4、5×10^4、2×104min^-1;对于对硫磷代谢的Vmax/Km值分别为2×10^4、5×10^5、1.11×10^5、1.43×10^5min^-1;对于马拉硫磷的值分别为5×10^3、5×10^4、2.5×10^3、1.67×10^4min^-1。96hLC50值与Vmax/Km值大体呈负相关,其中毒死蜱的相关性较弱,对硫磷及马拉硫磷的相关性较强（R^2值分别为0.2181、0.8490、0.5102）。研究结果说明P450在鱼类耐药性形成过程中发挥了阻碍作用。     

新型高效反应器组合系统处理奶牛养殖场废水试验研究

选择一种新型高效反应器系统对奶牛养殖场废水进行处理试验研究,这种反应器系统主要包括两级组合生物巢厌氧反应器和砂式沼液处理池。试验结果表明,该系统处理奶牛养殖废水速度快,两级组合生物巢厌氧反应器水力停留时间（HRT）仅为15h,处理效率高,砂式沼液处理池结构简单,对生物巢厌氧反应器出水处理效果好。该新型高效反应器组合系统对化学需氧量（COD）、生化需氧量（BOD）、氨氮（NH3-N）和总固体悬浮物（TSS）的平均去除率分别为97.6%、98.2%、81.3%和98.1%,出水体积质量平均值分别为89.0、27.1、15.7mg·L^-1和64.9mg·L^-1,满足国家二级排放标准。