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991.
结合冬瓜果实特点与营养吸收特性,探讨冬瓜氮磷钾化肥配施效应。结果表明,每产生1t冬瓜果实需要吸收的总养分为氮1174.8g、磷241g、钾2374g、钙1194g、镁141g、硫121g、硼3.1g和锌1.8g。在土壤有效磷丰富,有效氮、钾缺乏及施有机肥条件下,施磷稍微减产,OPT-N处理比OPT处理减产7.0%,OPT-K处理显著减产14.4%,种植效益降低8.5%及21.0%,氮、钾肥养分产出率分别为29.5kg冬瓜/kgN及61.2kg冬瓜/kgK2O。在土壤有效氮、磷、钾极缺乏及不施有机肥条件下,OPT-N与OPT-K处理分别比OPT处理显著减产21.2%及31.3%,OPT-P处理减产12.5%。种植效益降低56.9%、40.1%及99.1%。氮、磷、钾肥养分产出率分别为41.5kg冬瓜/kgN、81.3kg冬瓜/kgP2O5及61.0kg冬瓜/kgK2O。表明中低产田种植冬瓜时,更应重视氮磷钾肥的合理平衡施用。 相似文献
992.
治"愚"与"贫":农村高等教育的目标 总被引:3,自引:0,他引:3
本认为,困扰农村的一个重大问题是教育与经济双向贫困。而导致这一结果的根本原因是农村“愚”与“贫”的联姻。为此,提出建立以治“愚”与“贫”为目标的农村高等教育体系之设想。 相似文献
993.
994.
995.
Zhitong Yao Meisheng Xia Liuqin Ge Tao Chen Haiyan Li Ying Ye Hao Zheng 《Fibers and Polymers》2014,15(6):1278-1287
The clam shell (CS) waste was first modified by furfural and hydrochloric acid to prepare fillers FCS and ACS, which were then used as fillers in polypropylene (PP), as well as the commercial calcium carbonate (CC). These fillers were characterized and analyzed by means of X-ray diffraction (XRD), atomic force microscopy (AFM), particle size analyzer, Fourier transformed infrared spectroscopy (FTIR) and contact angle measurement. The mechanical and thermal properties of PP composites were investigated as well. XRD analysis indicated that the major crystalline phase of CC was calcite; of shell waste derived fillers, calcite and aragonite. The CC was fully hydrophobic, while the shell derived fillers were amphiphilic. Mechanical property studies showed that the incorporation of FCS played the role mainly of toughening the PP; of CC, CS and ACS, that of reinforcing. The optimum filler contents of CS, ACS and FCS could reach 5, 7 and 15 wt.%, respectively, to obtain a good balance between fracture toughness and stiffness of the PP composites. Polarized optical microscopy (POM) observation indicated that the inclusion of these fillers could promote the heterogeneous nucleation of PP. 相似文献
996.
Xian Zhang Xingyou Tian Xiayin Yao Jin Zheng Wentao Liu Yong Li Ping Cui 《Fibers and Polymers》2008,9(3):360-364
The isothermal and non-isothermal shrinkage behaviors of highly oriented Poly(ethylene terephthalate) yarns were investigated.
In isothermal measurements, shrinkage and shrinkage stress firstly monotonously increased due to more and more activated frozen
molecular segments with increasing time and temperature, and then relaxed at high temperature resulting from intermolecular
slipping of micro-fibrils. According to the different contributions of amorphous and crystalline regions to shrinkage behavior,
non-isothermal shrinkage and shrinkage stress curves were fitted by Gauss curves and the entire shrinkage process was divided
into three stages: contraction of micro-fibrils, contraction of extended interfibrillar tie molecules and relative displacement
of micro-fibrils. 相似文献
997.
用稀释50,100,150和200倍平衡营养液(GPNS)培养冬小麦。结果表明:GPNS稀释倍数为50,100倍时抑制小麦生长,而为150,200倍时则促进小麦生长,并能增加萌发的小麦胚乳内α-淀粉酶的活性。麦苗片叶绿素含量增加,叶片可溶性蛋白含量提高,根系活力提高,叶片在低温、干旱逆境条件下电解质外渗率下降,从而提高膜的稳定性,保证了细胞正常的生理功能。 相似文献
998.
Shengliang LIAO Shibin SHANG Minggui SHEN Xiaoping RAO Hongyan SI Jie SONG Zhanqian SONG 《农业科学与工程前沿(英文版)》2015,2(4):335
Twelve (+)-nopinone-based 2-amino-3-cyanopyridines 4a–l were synthesized from (–)-β-pinene. The structures of these compounds were characterized by FT-IR, 1H NMR, and ESI-MS. All the compounds were tested for their anticancer activity against lung cancer cell line A549, gastric cancer cell line MKN45 and breast cancer cell line MCF7 by MTT method, respectively. The results showed that compounds 4f, 4j and 4k had promising anticancer activity against these cancer cell lines, in particular, compound 4f exhibited broad-spectrum and highly efficient anticancer activity against cell lines A549, MKN45 and MCF7 with IC50 of 23.78, 67.61 and 53.87 µmol·L−1, respectively. The preliminary analysis of the structure activity relationship implied that the Br or Cl substituted group of the benzene ring in these derivatives significantly contributed to the anticancer activity. 相似文献
999.
1000.
采用4因素5水平旋转回归正交组合设计,研究了江淮地区小麦播期、密度、氮、磷肥4因素的综合效应,并建立以籽粒产量、蛋白质含量为目标函数的数学模型,通过计算机模拟寻优,筛选出小麦品种肖农12,亩产350公斤,籽粒蛋白质含量12%,较经济的综合农艺措施为:10月20—23日播种;基本苗15—16万/亩;施纯氮11.8—13.3公斤/亩;五氧化二磷5.4—7.3公斤/亩。 相似文献