不同受害程度的棉株对棉蚜种群的影响

通过室内对不同密度棉蚜两次为害棉株的生态学参数测定，结果表明：棉株在受到棉蚜二次为害后，无论是棉株生长点或是不同生长期棉株受害，均可影响棉蚜种群数量下降，增长率降低，发育历期增大，扩散率提高，体色趋变黄色。可以证明受害棉株明显存有诱导抗性，且６片真叶以后的诱导抗性大于６片真叶以前。     

MACHINE PARAMETER IDENTIFICATION AND FAULT DETECTION FOR THE ALTERNATOR SYSTEM

In this paper, the machine( physical) parameters of the alternator system are on-line estimated on the basis of the derived system continuous-tims model, using Recursive Least-squares Estimation and Inverse Calculation Method proposed by Authors. Therefore, the estimated machine parameters can effectively track the changes of their true values and accomplish the fault detection for the alternator system. This paper gives a new way for machne parameter estimation and fault detection of the alternator systems.     

棉花GhFTL1基因的克隆及初步功能分析

通过RT-PCR结合RACE技术,从新疆陆地棉品种新陆早33中克隆到一个FT类似基因,命名为GhFTLl基因(登录号:HM631972).该基因ORF(Open Reading Frame)全长为525 bp,可编码174个氨基酸,与其它植物中克隆的FT同源蛋白高度相似,含有FT蛋白亚家族两个关键的氨基酸残基及保守氨基...     

混合实验仪参数与和面仪、快速黏度仪参数的关系及其对面条品质的影响

快速准确的评价方法对面条品质遗传改良至关重要。法国肖邦公司(Chopin Technologies, France)最新推出的Mixolab分析仪可以同时测定面粉加水后恒温揉混及面团升温后蛋白质弱化和淀粉糊化特性,明确其与现有类似仪器如和面仪和快速黏度测试仪等的关系对小麦品质评价具有重要意义。利用混合实验仪、和面仪、快速黏度测试仪测定了60份小麦品种的有关参数,并对面条品质进行感官评价,分析了相关参数间的关系及预测面条品质的可靠性。结果表明,可以用混合实验仪的稳定时间很好地预测和面仪参数峰值曲线面积、峰值时间和8 min带宽,可分别解释其变异的75.7%、74.6%和56.5%;混合实验仪的C3值、C4值、C5值和吸水率是预测淀粉糊化特性的重要参数,C3值、C4值和C5值与峰值黏度、低谷黏度和最终黏度的相关系数在0.57~0.62之间,吸水率与峰值黏度和最终黏度的相关系数分别是-0.62 (P < 0.01)和-0.55 (P < 0.01)。混合实验仪对面条色泽预测的准确性高达75.7%,但预测面条软硬度、黏弹性、光滑性等口感品质性状的准确性较低,只能解释变异的13.2%~30.5%,因此,面条口感质地特性还应以感官评价为主。     

Operational Analysis of Open Untreated Sewage Source Heat Pump System

The effective sewage intake technology is prerequisite for the untreated sewage source heat pump system to run steadily. In terms of the insufficiency of current sewage intake technologies, an open sewage intake integration technology is proposed. The mathematical model and the distinguish basis of critical state are established for the sewage intake characteristic by defining some important operating parameters, such as the blocking coefficient, the contamination density and the section coefficient. Furthermore, the change rule of each critical operation parameter is observed along with the various initial parameters. The result can provide the theoretical basis to design the open intake integration technology.     

Least-square-based Optimization of Frequency Response Function Estimation in Modal Parameters Identification

The accuracy of modal parameters identification has the influence on the quality of dynamic characteristics analysis of mechanical structure directly. And the precision of the frequency response function estimation has the great influence on the accuracy of modal parameters identification. In the engineering the frequency response function can be estimated by the average power spectrum and cross-power spectrum with the hel Pof FFT. As the result of limited frequency resolution in the course of FFT and the noise, the accuracy of modal parameters identification is influenced by the frequency response function estimation. This paper has put forward a least-square-based optimization of frequency response function estimation in modal parameters identification. According to the optimized frequency response function, the peak value can be searched to identify the damped natural frequencies and damping ratio directly. An experiment has been made to validate the proposed method. The result indicates that the damped natural frequencies and damping ratio identified by the optimized frequency response function are closer to the true results than which without the optimized frequency response function. So the accuracy of modal parameters identification can be improved by adopting the proposed method.     

Constitutive Model for Negative Simple-sheared Soil-concrete Interface

Negative shear property of soil-concrete interface is one critical issue in civil engineering. According to negative simple shear tests of soil-concrete interfaces with various water content, quantitative analysis on changes of shear strength, friction angle and cohesion force of negative sheared interface against positive shear experience were conducted. Several empirical formulae were proposed for above changes, and critical positive shear ratio was put forward. Based on improved stress-strain equation, mathematical model for tangent modulus of negative sheared soil-concrete interface was established. This new model consists ten parameters which can be determined by simple shear test. Process for determining these ten parameters was presented, and empirical values of them were obtained. Simulations for stress-strain curves of soil-concrete interface were carried out, and good ability of the model was found.     

利用可调参数式行星球磨机超微粉碎野生黑木耳的试验研究

采用自行研制的可调参数式行星球磨机对野生黑木耳进行了超微粉碎试验研究。对野生黑木耳进行精细加工,为开发出富含野生黑木耳超微粉的各种食品提供条件。试验采用5因素二次回归正交旋转组合试验设计的方法,建立了试验因素与试验指标间影响关系的数学模型,通过优化计算得到野生黑木耳超微粉碎的最佳工艺参数为:公转盘转速为574r/min,粉碎时间为4.2h,球料比为5,磨筒倾角为69o,填充率为23%,理论最佳颗粒粒径为3.9μm,实验值为4.12￣7.79,与理论最佳值基本一致,因此试验得出的数学模型可靠。同时进行了不同细度黑木耳粉的动物喂养实验,结果表明,黑木耳超微粉在净消化率、生物学价值、净利用率和功效比值方面均显著优于黑木耳粗粉和黑木耳细粉,对黑木耳进行超微粉碎具有实际意义。     

Analysis of competitive ability among genotypes of perennial ryegrass. II. Effect upon dry matter production

Summary An analysis of the effects of competition upon the dry matter production per plant (after square root transformation) revealed no significant differences between the two genotypes of perennial ryegrass (Lolium perenne) used as regards the pressures which they exerted upon each other. Their response to these pressures differed significantly however. Using these estimates of the pressure and response parameters it was shown that the impact of intra-genotypic competition upon these two genotypes was considerably greater than that of inter-genotypic competition. In general this will be true whenever the pressure and response parameters take the same sign. Intensity of competition increased linearly with vigour of growth in both cutting regimes, though changes in vigour had a significantly greater effect upon the intensity of competition under frequent cutting.     

Dynamic Modeling and Analysis for a Humanoid Robot

To resolve the kinematics modeling and dynamics modeling of a humanoid robot with complicated machine, a modeling method based on the conventional mechanism combined with neural network is presented. First the kinematics formulas are deduced by analyzing its geometry structure. Second, the dynamics models are built up with Lagrange-Euler method combined with the define of interactive force among all parts of the humanoid robot. The interactive force is realized by neural network method. Finally, the true robot parameters are applied to the model. The simulation results show the validity of the modeling. So, the method is practical and available.     

Last days in the Carteret Islands? Climate change,livelihoods and migration on coral atolls

It is widely assumed that the impacts of climate change on atolls will render them uninhabitable. The Carteret Islands, an iconic Pacific atoll, is experiencing physical changes, documented in the media, the outcome of multiple factors, alongside critical economic livelihood problems. Its population has sought to resettle on nearby Bougainville Island, but land has not become available. The search for migration opportunities parallels trends on coral atolls elsewhere where survival strategies have involved regional and international ties, with cultures of migration, focused on more distant international destinations. Carteret Islanders have not been able to mobilise similar relationships. For many atolls and atoll states, migration has increasingly become a livelihood strategy, irrespective of climate change. That is likely to become even more true in the future, but the outcome will be dependent on policies and practices in metropolitan destination states.     

Characteristics of Filling Process and Factors of Differential-pressure Cast for Thin-wall Castings

Filling process of differential-pressure cast for thin-wall castings of aluminum alloy is simulated with the hydraulic simulation method. The effects on filling fluid pattern was taken by the figure and amount of the ingate and the wall width of castings are researched. It is shown that the wall width of castings has obvious effect on critical pressure increase rate and critical filling rate, the thinner the wall width of castings is, the bigger the critical pressure increase rate and critical filling rate are; but the figure and the amount of the ingate has no obvious effect on the stationarety of filling. On the basis mentioned above, it is carried out that numeric simulation of filling process of differential-pressure cast and the process design of defferential -pressure cast to some large-scale thin-wall cabin-shape parts, and the result showes that are the smooth and stepwise filling,and the project of differential pressure cast is instituted by the process parameters, which is provide by the hydraulic simulation method. It provides the reference for the produce of this kind of castings.     

离子注入辣椒出苗特性的研究

采用生物改性离子注入设备对辣椒干种子进行了N+离子注入,详细进行了干种子注入N+离子后的育种和生长特性研究,主要研究了N+离子注入后辣椒种子的出苗率、出苗时间与N+离子注入工艺参数之间的关系,通过研究,获得了致死率为50%的离子注入工艺参数,同时,得到了离子能量和注入剂量相关的致死临界曲线,该致死临界曲线类似于反比例曲线。研究表明,致死临界曲线上任一点的离子能量和注入剂量之积在2×1017keV.ions/mm2-2.5×1017keV.ions/mm2范围内,即当离子能量与注入剂量之积大于2.5×1017keV.ions/mm2时,种子全部致死,当离子能量与注入剂量之积小于2×1017keV.ions/mm2时,将有一定比例的种子存活。     

华北地区夏玉米临界氮稀释曲线和氮营养指数研究

为了验证玉米临界氮稀释曲线在我国华北地区的适用性,探讨以氮营养指数评价玉米氮营养状况的可行性,以郑单958为材料,设置5个氮肥处理(0、60、120、180和240 kg N hm^-2),利用2年定位试验数据研究了夏玉米临界氮稀释曲线和氮营养指数。结果表明,一定范围内随着施氮量增加,地上部生物量(W)显著增长。玉米各生育时期不同氮肥处理的生物量和氮浓度数据可经统计分析分为限氮和非限氮两组,据此计算各生育时期临界氮浓度(N_c)并建立了夏玉米临界氮稀释曲线模型(N_c = 34.914W^-0.4134),模型参数与已有报道具有较好的相似性。根据模型推算的氮营养指数与相对氮累积量、相对地上部生物量和相对产量均具显著相关性。因此,利用临界氮稀释曲线和氮营养指数可以预测华北地区夏玉米植株临界氮含量和表征植株氮营养状况。