广义中心反对称矩阵反问题的最小二乘解

给出了广义中心反对称矩阵反问题的最小二乘解及其最佳逼近解的表达式.对该类矩阵反问题,得到了有解的充分必要条件,并在有解条件下给出了解的一般表达式.     

Ion Equilibrium in the Soil Solution in Long-term Fertilization Experiment on Sandy Soil

In the conditions of long-term experiment carried out in the experimental field of Warsaw Agricultural University - SGGW at _ yczyn, ion concentration in the soil solution were examined as well as the relationships shaped between ions in the soil solution due to long-term diversified mineral and organic fertilization. Soil solution was obtained by the vacuum method and the concentration of particular ions in the soil solution was determined by the ICP method. Mineral and organic fertilization and liming significantly affected chemical composition of the soil solution and the relationships between particular ions in the soil solution. The lowest concentration of ions in the soil solution was observed in the control plots (not fertilized). Mineral and organic fertilization as well as liming caused the increase of ion concentration in the soil solution. In the plots with mineral fertilization alone K + and NH + 4 ions predominated in the cation structure in the soil solution. In the case of liming the share of Ca 2+ ions increased. Independently from the system of fertilization used, CI m and HCO m 3 ions predominated in the anion structure. The application of organic fertilization affected to the highest degree the concentration of aluminium ion in the soil solution significantly limiting the share of this ion in the cation structure.     

Effect of foliar and soil applications of zinc sulphate on zinc uptake,tree size,yield, and fruit quality of mango

To compare the effect of methods (foliar and soil) and rate of application of zinc sulphate on zinc and phosphorus uptake, tree size, yield and fruit quality of mango (Mangifera indica L.) cv. Dusheri, zinc sulphate was applied as a foliar spray application (0.25, 0.50, 1.0%) and soil (0.5, 1.0, 2.0 kg tree^‐1) treatments during the second week of October (during flower bud differentiation period). All the zinc sulphate treatments of soil and foliar spray were effective in increasing the leaf zinc concentrations above recommended adequate level of (>20 mg kg^‐1) whereas control trees maintained low leaf zinc concentrations (13.8 to 13.3 mg kg^‐1). The uptake of foliar‐applied zinc was more rapid than that of soil applied zinc. All the treatments of zinc sulphate except the foliar spray treatment of zinc sulphate (0.25%) significantly increased zinc concentrations in the fruit pulp as compared with those in the control trees. The percent increase in the stem girth of trees was highest with the soil application of zinc sulphate (0.5 kg tree¹) followed by foliar application of zinc sulphate (1.0%) as compared with all other treatments. The percent increase in the tree canopy volume was highest with the foliar application of zinc sulphate (1.0%) followed by soil application of zinc sulphate (1.0 kg tree¹) as compared with control and all other treatments. There was no significant (P<0.05) increase in yield, fruit size and weight, pulp or stone weight with any treatment of zinc sulphate. Total soluble solid (TSS) in the fruit was significantly higher (18.6%) with the treatment of soil application of zinc sulphate (0.5 kg tree¹) as compared with all other treatments of zinc sulphate and the control. Acid and sugar content of the fruit was not significantly affected by the foliar or soil application of zinc sulphate.     

HPLC法测定复方防己口服液中粉防己碱和防己诺林碱的含量

为了用HPLC法同时测定复方防己口服液中粉防己碱和防己诺林碱的含量.采用Diamonsil C 18柱(5μm,4.6 mm×250 mm),以乙腈-0.2％磷酸水溶液-三乙胺(63∶37∶0.05)为流动相,流速为1.0 mL/min,检测波长282 nm的液相检测方法.结果表明,在此色谱条件下,粉防己碱和防己诺林碱的分离良好,分别在20.52 ～ 205.2μg/mL和17.84 ～ 178.4 μg/mL浓度范围内峰面积与浓度呈良好的线性关系.按外标法以峰面积计算进行测定,粉防已碱和防己诺林碱的平均回收率分别为98.15％和97.35％,RSD分别为1.39％和1.90％.表明该方法简便,快速,准确,适用于防已散中粉防己碱和防己诺林碱的含量测定.     

陕西农业“走出去”的现状、问题及对策

分析了陕西农业"走出去"的现状,已取得了显著成效,但也存在出口贸易规模小,市场竞争力较弱;境外投资障碍多,支持不足;农业国际交流合作合作面较窄、经济效益低等问题和困难。鉴于此,提出了相应的对策建议。     

法定民间体育组织若干问题与发展对策探析——以广州市为例

采用文献资料法、问卷调查法、访谈法等,对广州市法定民间体育组织的成立概况、资金情况、内部治理、项目开展及评估、外部关系、影响因素等进行调查,在此基础上分析其存在问题,包括数量少,发展不平衡;成立条件过高;经费不足,来源渠道狭窄;内部治理不规范,自律性不足;评估不规范,监管不力;宣传、信息公布不到位,诚信度不高等。并提出发展对策,主要有：加强民间体育组织自身能力培养;政府提高重视,并正确引导;促进社会公民的参与;鼓励市场企业组织的支持等。从而为法定民间体育组织的发展提供参考。     

广东省恩平市产业转移园区土地利用问题研究

以广东省恩平市产业转移园区为例,通过重点分析该园区在规划和建设过程中在土地利用方面可能存在的问题,并结合恩平的实际情况,提出解决和避免这些问题的办法。     

适合5种观叶植物水培培养液的筛选

研究筛选适合观叶植物的水培培养液,观察金边吊兰（Chlorophytum comosum）、鸭跖草（Commelina commu-nis）、袖珍椰子（Chamaedorea elegans）、绿萝（Scindapsus aureum）和黑美人（Aglaonema commutatumcv.‘Sanpemo’）在水、单纯的营养液和在营养液中分别添加0.5 mg/L IAA和0.5 mg/L IBA的水培效果。结果表明：在营养液中添加IAA的培养液比较适合鸭跖草和袖珍椰子的生长;在营养液中添加IBA的培养液比较适合绿萝和黑美人的生长;3种培养液和水不适宜金心吊兰的水培生长。     

不同EC值营养液对大花蕙兰生长及开花的影响

以大花蕙兰大花品种金门和小花品种红祖为材料,研究了不同EC值营养液对大花蕙兰生长及开花的影响.结果表明:大花品种金门以营养液EC值为1.4～2.8 mS/cm时植株生长发育较好,开花品质最佳,其中EC值为2.1 mS/cm时效果最好,平均单株花箭数为6.15枝,平均花箭长度达到60.28 cm,平均单枝小花数达到13....     

雾培与液培对黄瓜根系氮代谢相关酶活性的影响

采用雾培和液培(深液流)栽培系统,研究了不同无土栽培方式对津绿‘21-10’和迷你黄瓜‘22-405’根系氮代谢的影响。结果表明,在整个生育期,雾培和液培黄瓜根系硝态氮(NO3--N)和铵态氮(NH4+-N)含量、根系活力、硝酸还原酶(NR)活性、谷氨酰胺合成酶(GS)活性、谷氨酸脱氢酶(GDH)、谷草转氨酶(GOT)活性、谷丙转氨酶(GPT)活性、游离氨基酸和可溶性蛋白质含量总体上均呈现出先升高后降低的变化特点,其中在处理的前20 d液培处理的各项指标均大于雾培,且在处理的第20天达到最大,而雾培处理的各项指标最大值是在处理的第30天,且在处理的30 d之后,雾培根系各项指标均比较高。在不同基因型品种之间,津绿‘21-10’根系各项指标变化幅度大于迷你黄瓜‘22-405’,但品种之间无显著差异。结果说明在生育前期液培黄瓜植株根系氮的吸收和代谢能力比较强,而在生长中后期雾培黄瓜根系氮的吸收和代谢能力增强。