30年来长武县耕地数量与农业经济发展计量关系分析

针对长武县近30年来农业经济快速发展和耕地数量锐减的现实,通过建立向量误差修正模型,运用脉冲响应函数、方差分解方法,对1980-2010年长武县耕地数量与农业经济数据进行计量关系分析,探索二者间的互馈效应.结果显示,农业经济受耕地数量减少的影响效应为正但不显著,近30年的脉冲响应均值仅为0.8,10年尺度上分别为0.4、0.8、1.6.而耕地数量受农业经济发展的影响效应为负,并随时间发展该负效应持续增强,10年尺度上均值分别为-0.3、-0.9、-2.8;30年来长武县耕地资源的变化并未对农业经济的发展有显著促进作用,其时期内最大贡献率仅为22％.而耕地数量减少主要受农业经济发展的影响,后者对前者的贡献率时期内从最大值88.9％稳定到78％.表明耕地数量减少在促进农业经济发展上存在过度损失,农业经济的发展是耕地数量减少的主要原因.发展农业经济亟需挖掘社会其它要素的作用,以保证耕地数量的持续稳定,避免不合理利用.     

海南省农民收入与信息消费的实证研究

利用自回归模型、脉冲响应函数和预测方差分解分析了海南省1988～2008年农民收入与信息消费之间的关系。结果表明,农民收入与信息消费之间存在着较强的互动关系,增加信息消费能有效的促进农民收入的持续增长,而农民收入的增加也促进农村信息消费的发展。但目前农村信息消费水平低,对农民收入影响不是很显著,应建立长期有效的信息消费激励机制,以促进农民收入的持续稳定增长。     

带脉冲的变耦合时滞神经网络的同步

主要讨论一类带脉冲的变耦合时滞神经网络的同步问题.通过构造Lyapunov-Krasovskii泛函,运用线性矩阵不等式(LMI)技术并结合Kronecker积来获得耦合神经网络全局同步的充分性判据,并且所获得的判据依赖于时滞.由于这样得到的判据是LMI形式,因此,可以由数学软件MATLAB的LMI工具箱对所获得的判据进行有效的验证.同时,对细胞激活函数做了更为一般的假设,从而使结论在LMI下可以减少保守性.     

新疆农机化发展与农民增收效应关系研究——基于VAR模型

农机化发展是推动新疆农业发展、农民增收、农业结构调整的基础物质保障和战略支撑,农机总动力是反映和评价农机化发展水平的一个重要指标。为此,通过运用1978—2012年新疆统计数据,采用单位根检验、协整检验、VAR模型、脉冲响应函数和差方分解方法,研究了农机总动力与农民人均纯收入两者关系。研究表明:在农业生产中,农机化的发展对农民增收效应明显,农民增收也有效地推动农机化发展,并根据两者之间的实证结果得出相应结论。最后,对构建新疆地区农机化发展与农民增收良性促进机制提出政策建议。     

兴奋或抑制细胞内PKC或cAMP对不同脉冲频率GnRH刺激下GTH表达水平的影响

观察兴奋或抑制细胞内cAMP和PKC后,LH和FSH对不同脉冲频率GnRH刺激的应答情况,分析LH/FSH表达的受体后信号转导机制。结果表明,使用cAMP的兴奋剂或抑制剂使细胞cAMP含量升高或降低时,显著影响了LH的应答,但对FSH的应答影响不显著;使用PKC的兴奋剂或抑制剂使细胞PKC活性升高或降低时,既显著影响了LH的应答,也显著影响了FSH的应答。两者均随着PKC活性的升降而升降。     

Optimum Design of New-style Impulse Variable Speed Device Based on Invariable Impulse Value

The impulse value of a impulse mechanism has a notable influence on the dynamics capability of impulse variable speed device. Basing on this point, the authors take crank-rocker mechanism in series with slider-crank mechanism as impulse mechanism when we design the impulse variable speed device. The link used to adjust the speed is applied in slider-crank mechanism which has no quick-return characteristic, so the advance-to return-time ratio keeps stable when we adjust its speed. The speed fluctuation also keeps invariable. The new method overcome the default that this kind of impulse variable speed device has a notable speed fluctuation. At the same time, ADAMS software is used to optimize and show the real motion law. From the simulation result we can get the speed fluctuation is down to 18% in the whole process. The change of speed fluctuation is down to 1%. The result is better than other mechanism like this category.     

去除污泥中重金属的研究进展

有效降低城市污水处理厂污泥中重金属总量是污泥大量农用的关键.现阶段,国内外对于污泥中重金属的去除主要有化学试剂浸提、生物淋滤、电动修复及超临界流体萃取等方法.为此,从原理、研究现状及应用等方面对这些技术方法的研究进展进行综述,并比较了其对污泥中重金属的去除效率及优缺点,从而为污泥的无害化、资源化提供一定的理论依据.     

电流变减振器用于铣床振动控制的理论研究

研究了电流变减振器在铣床振控制中的应用。理论分析表明：电流变减振器的刚度及阻尼随外加电场强度的增加而增大，主振系统的振幅随电场强度的增加而减小。电流变减振器的减振效率随着电场强度的增加逐渐增大，但并不是场强越大效果越好，而有一最佳值。只要场强选取适当，采用电流变减振装置可以控制铣床心轴颤振现象的产生。     

Behavioural and EEG changes in sheep in response to painful acute electrical stimuli

Objective To measure acute pain in sheep, based on a human pain model, and examined changes in both electroencephalogram frequency spectrum and behavioural responses to increased electrical stimulation in sheep. Design Analysis of variance (treatment and animal effects) for stimulus intensity where each animal received each electric shock treatment given in the order 0, 5,10 and 20 mA. Procedure Eight sheep with electrodes implanted over the surface of the brain were examined for escape-avoidance and electroencephalogram responses to four levels of electrical stimulation from 0–20 mA. Results With increasing stimulus intensity at the time of feeding, the sheep were more hesitant to return to the feeder or remain near the feeder following stimulation. There was little difference between the 0 and 5 mA stimuli for any of the behaviour variables (P > 0.05). However, there were marked increases in the time taken to re-approach the feeder after receiving an electric shock of 5 mA and of 20 mA (P < 0.05; mean values 3 and 119 s, respectively) and remaining near the feeder for 5 s (P < 0.001; mean values 10 and 167 s, respectively). Following the stimulus, there was an overall increase in the electroencephalogram power spectrum in the first four seconds, which then rapidly returned to normal. In particular, the 20 mA stimulus resulted in higher absolute power values than in the control (0 mA) treatment for delta 2 (P < 0.001), theta 1 (P < 0.05), theta 2 (P < 0.05), alpha 1 (P < 0.001), alpha 2 (P < 0.001) and beta 1 (P < 0.01) band-widths. Similarly, for the 10 mA stimulus, the absolute power values were greater than the control treatment for delta 2 (P < 0.05), alpha 1 (P < 0.01), alpha 2 (P < 0.001) and beta 1 (P < 0.01) bandwidths. Conclusion The experiment suggests that a human acute pain model is applicable to sheep and that these electroencephalogram changes may provide a good measure of acute pain in sheep.     

The Analysis of Impulse Response of Bank Landing to the Impact of Monetary Policy in China

Abundant researches approve that the bank-lending channel is the main monetary transmission channel in China recent years. But the most of investigations only focus on the behavior of the gross bank-lending index in the monetary transmission, and the further investigation hasn't been carried on. This paper divides the gross index of bank lending into the short-term and mid-, long-term loans based on the internal and external researches. It analyzes how the financial institutions adjust their lending policy under the impact of the monetary policy of the central bank and the effect of the adjustments on the macroeconomic, making the further study of the bank-lending channel in monetary transmission in China.