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21.
通过分析营养元素对油松抗旱能力的影响规律,以期为科学施肥提供理论依据。试验设置S1(常规对照)、S2(清水对照)、S3(N)、S4(NK)、S5(NPK)5个处理,3次重复。SOD活性S5在5、6、7、8月分别比S1处理提高了68.66%、64.54%、36.02%、30.03%,差异显著;POD活性S5分别高于S1处理79.96%、117.82%、51.65%、41.28%,差异显著;CAT活性S5在6、8月分别比S1提高了35.86%、33.51%,差异显著;PPO活性S5分别比S1提高92.18%、125.15%、74.95%、57.77%,差异显著;S5处理电导率始终处于最低值,分别比对照(S1)降低40.46%、24.73%、25.99%、55.55%,差异显著。S5对提高水分胁迫下油松幼苗保护酶活性和降低电导率效果最佳。  相似文献   
22.
为研究软母线刚度对特高压电气设备地震响应的影响,建立考虑刚度的软母线位形函数、最大弧垂及软母线最大应力的计算公式。通过软母线连接的特高压设备振动台模型试验与有限元计算的对比分析,验证了笔者给出的考虑刚度的软母线位形函数、最大弧垂计算公式的正确性。有限元分析结果表明:当软母线的刚度增大时,软母线的垂跨比减少,软母线与特高压设备之间的地震耦合作用增强,增强了软母线对设备的拉伸作用,从而使设备的地震反应随着导线刚度的增加而增加。软母线刚度对频率较高的设备其地震反应的影响要大于对设备频率较低设备地震反应的影响。  相似文献   
23.
As kindergarten class decorate enhancement, to the requirement of the electrical design more and more is also high. This paper is based on the present of the more common kindergarten, respectively from the design and high voltage electricity design two aspects and so on many small point to electrical design in this paper.  相似文献   
24.
紫外吸收法、电导率法检验大白菜种子活力的研究   总被引:2,自引:0,他引:2  
通过人工老化种子和不同年代种子具有的活力不同,以发芽指数为活力参考标准来探索种子浸泡液电导率测定法和紫外吸收测定法是否适合大白菜种子活力的快速检测.结果表明:大白菜种子紫外区随着波长的缩短吸收值增大,但经玻璃比色杯滤过后会在286 nm下显示吸收峰,随着种子活力的降低286 nm下的OD值呈上升趋势,对发芽率高于85%的种子适用,而对于活力过低的种子检验不可靠;随着种子活力的降低电导率呈上升趋势,但对活力差异较小的种子间检验不可靠.因此,对发芽率合格范围内的种子可以根据286 nm(玻璃比色皿)紫外吸收值评价大白菜种子活力的高低,其他的种子可参考电导率值比较种子活力.  相似文献   
25.
Under the mode of customization-oriented multi-varieties and small-batch production, the requirement of design and manufacturing integration exists in sheet metal processing shops, which has the characteristics of great varieties of sheet metals, huge design data and heavy production tasks. To meet the requirement, an integrated operation mode for sheet metal processing shop of electrical equipment is presented. The mode realizes the information sharing and business collaboration from the sheet metal 3D CAD, 2D outspread, process design, optimal sheet metal layout, NC programming to NC machining. The integration framework based on service oriented architecture(SOA), function structure and operation process of the system is constructed. The system has been applied to an electrical equipment manufacturer in Chongqing, and good results are obtained.  相似文献   
26.
An interpolation algorithm with corresponding point matching is presented for interpolating two-dimensional reconstructed images of electrical impedance tomography(EIT)to realize three-dimensional reconstruction. The calculation methods of the gradient and its orientation angle have been adjusted according to the characteristic of the EIT data, and the interpolated slice shows good quality. The experimental model is a 2.1 S/m cylinder agar block immersed in a cylindrical water tank. The comparisons of the presented algorithm to the linear interpolation and the shape-based interpolation are made. The results show that corresponding point matching algorithm can ensure both accuracy and computational efficiency, thus the algorithm satisfies the requirements of the real-time EIT monitoring.  相似文献   
27.
This paper has applied the var cost to the theory of spot price.An augmented Lagrange method is employed to develop the exact model of spot price of active power and reactive power,and the physical means of Lagrange multipliers are explained.The numerical examples are given to demonstrate the validity of the proposed model.  相似文献   
28.
In order to improve the error in image reconstruction caused by changeable positions of the electrodes in closed electrical impedance tomography, we propose an open electrical impedance tomography (OEIT) model using fixed electrode array. The problem was approximately assumed to be a virtual field by defining certain local sensitive area instead of solving the boundary problem in the whole electromagnetic field strictly. Modeling and simulation of OEIT have been conducted to define reasonable boundary parameters and electrode array structure. The finite element method is used for forward computation while Newton one step error reconstructor is used for image reconstruction. The target position, area and conductivity change can be reflected by the relative change of the boundary voltage and the reconstructed image is clear. Better resolution and positioning accuracy can be obtained in the shallower surface of the body by OEIT, so it is valuable in clinical applications.  相似文献   
29.
Electrical impedance tomography (EIT) system must have the properties of high precision and speed, thus the digital phase sensitive detector (DPSD) based on the field programmable gate array(FPGA) is developed for data collection of EIT. Based on the principle of DPSD, the relationship between signal to noise ratio (SNR) and sample resolution as well as total number of samples is deduced. An implementation scheme of this system and a method of designing analog to digital converter (ADC) clock based on direct digital synthesis (DDS) technology are provided. The system adopts high speed multi channel ADC and low jitter clock conditioner for ADC. Real time DPSD is implemented with FPGA. The experiments show that the measurement accuracy reaches 0.03% and the SNR reaches 85 dB. The agar phantom experiments prove that the performance of the DPSD meet the designing requirement for EIT.  相似文献   
30.
There are more than two power source in Hybrid Electrical Vehicle(HEV). By using of assist accelerating, power regeneration, Idle stop and power management, HEV gains more acceleration performance and more fuel economy and better gas emission than Conventional Vehicle(CV). With Integrated Starter and Generator(ISG) as a auxiliary power source, batteries and battery control module and power manage module as a Load leveling Device (LLD), two prototype HEV separately equipped Manual Transmission (MT) and Continuously Variable Transmission (CVT) was successfully developed.  相似文献   
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