中国冬播小麦面粉颗粒度分布及近红外透射光谱测试技术研究

面粉颗粒度是影响小麦食品加工品质的重要性状。以2001－2002年度来自北部冬麦区、黄淮冬麦区、长江中下游冬麦区和西南冬麦区的256份小麦品种（系）为材料，用激光散射颗粒度分析仪和近红外透射光谱技术对面粉颗粒度进行了研究。结果表明，我国小麦面粉颗粒度分布特点为从北向南，硬质麦分布比例逐渐减少，软质麦分布比例逐     

不同颗粒大小对高光谱估算土壤有机质含量的影响

研究旨在对不同颗粒大小的土样进行土壤有机质含量高光谱估算建模,以期得到土样制备时合适的土样颗粒大小,减少不必要的工作量。笔者对过10、20、60、100目筛的土样进行高光谱数据测量,并对光谱数据进行反射率(R)、反射率一阶导数(R’)和反射率倒数对数[Log(1/R)]3种光谱数据变换,然后运用偏最小二乘回归法(PLSR)、支持向量机法(SVM)和PLSR-SVM相结合的方法建立土壤有机质含量估算模型。研究结果表明：土壤颗粒大小对土壤光谱反射率有明显影响,颗粒越小,土壤光谱反射率越高;运用PLSR-SVM建立的SOM估算模型比只利用PLSR或SVM建立的模型精度高;当土壤颗粒大小＜0.25 mm时,对于SOM光谱估算模型精度的提高没有太大的帮助。该试验为进行土壤有机质含量高光谱估算制备土样提供指导。     

A Design Method of Photodetector in Laser Particle Sizer

A kind of the concentric circular photodiodes array is discussed.Via theoretic analysis and derivation,the principle and procedures of design of the detector are proposed,and obtain expressions for the design.     

Stability of Particle size Improved Roadbed in Permafrost

Roadbed stability, including thermal and strength stability, is the ability of roadbed to adapt to pavement settlement, slurry effusion, shear slide and haunching up of the roadbed resulting from moving vehicles and many natural influences. Thermal stability is the sensitivity of the thermal state of the roadbed to the external environmental condition. It is the key point of the roadbed stability in permafrost. Research concerning roadbed thermal stability in permafrost is analyzed, and the judgment principle of thermal stability is discussed. The regular change of the ground temperature and deformation of particle size improved roadbeds are analyzed by studying field observation data of the particle size improved roadbed after two freezing and thawing cycles. We conclude that the particle size improved roadbed can raise the upper limit of frozen soil. Based on the judgment principle, the particle size improved roadbed is regarded as a new type of stable structure.     

氨基酸分析仪法快速测定玉米籽粒中赖氨酸含量

以9 个高赖氨酸玉米和2 个普通玉米杂交种籽粒样品为材料,用日立L-8900 型全自动氨基酸分析仪对高赖氨酸玉米和普通玉米籽粒中赖氨酸含量进行定量测定。了解全自动氨基酸分析仪的检测效果是否可以很好的比较普通玉米与高赖氨酸玉米籽粒中的赖氨酸含量。结果表明高赖氨酸玉米籽粒赖氨酸含量介于0.34%~0.42%之间,普通玉米赖氨酸含量介于0.24%~0.25%,存在显著差异。日立L-8900型全自动氨基酸分析仪法测定玉米籽粒中赖氨酸含量与其它传统方法相比较,该方法快速、简便、灵敏度高、重现性好、样品需求量少,可以较好的在玉米育种中应用。     

物性测试仪研究休闲食品的特性

目前大多数休闲食品的品质评价仍以感官评价为主,缺乏科学性。以物性测试仪来评定休闲食品的特性,将它们的品质特性进行量化。试验证明物性测试仪不仅能够较准确、全面地反映休闲食品的多项品质特性,而且与感官评价具有高度的相关性。物性测试仪可以更加科学地对它们的品质特性进行评价。     

Influence of Pile Driving on Soil Resistance in Clay

With the increase of platform size, pipe piles with super large diameter and deep penetration are increasingly used in practice. In order to make accurate prediction of pile drivability, it is essential to evaluate the change of the soil properties under pile driving exactly, and it is the premise to predict the pile bearing capacity after pile driving. In order to learn more about the change of clay properties during pile driving, analysis on the pile driving record of 36 piles in Bohai area is conducted. According to the analysis, the soil resistance in the clay layers decreases as the depth increases, and it is very different from that in the sand layer. The FEM method is used to discuss the mechanism of this decrease. The back analysis is carried out to get more information. The results show that the clay properties are affected by the dynamic effect. The undrained shear strength of clay approximately decreases with the increase of thickness of the layer linearly. At the same time, a prediction is conducted based on results, and the result is closer to the pile driving record than that calculated by method normally used today.     

One-Dimensional Nonlinear Consolidation Analysis of Clay Considering Structural Stress

One-dimensional nonlinear consolidation equations have been established taking into account the effect of structure stress ratio of natural clay and stepped time-dependent construction loading. Crank-Nicolson formula is adopted to solve these equations using the finite difference method. Numerical results are compared to those of linear and nonlinear consolidation taking no account of structure stress. Finally, effects of nonlinear parameter η/c on consolidation are analyzed, which indicates that consolidation rate increases with the decrease of η/c. Numerical results of considering structure stress or not are similar initially. With the development of consolidation, the nonlinear results of not considering the structure stress overestimate the effect of nonlinearity.     

Numerical Analysis on Dynamic Response of Saturated Elasto viscoplastic Soft Clay

In the framework of porous media model developed from mixtures theories, Solid skeleton of soft clay was viewed as elasto viscoplastic material,and an elasto viscoplastic model of saturated soft clay was established. According on the model of saturated so     

Prediction Analysis on Equivalent Resilient Modulus of Clay Subgrade of Water Network Intensive Areas

According to unsaturated soil basic theories, equilibrium moisture of clay subgrade is predicted based on the updated studies of soil suction and soil water characteristic curve. Also, the bilinearity constitutive experience model of resilient modulus of clay soil is presented by triaxial repeated loading tests in laboratory. Using above mentioned results, a prediction method of equivalent resilient modulus of clay subgrade is established by comprehensively considering subgrade moisture and stress condition. Then, based on the concrete engineering, the prediction function of equivalent resilient modulus of the clay subgrade is provided by taking ground water table and subgrade height as centers. Compared with the results of other traditional testing methods on the same test road, the new prediction method may be used in practice. The results provide new perspectives and standpoints to determine the equivalent resilient modulus mechanics features of clay subgrade structure from two aspects of equilibrium moisture and stress condition.     

基于Weibull模型的细粒尾矿粒径分布

尾矿细粒化是矿业发展趋势,细粒尾矿的粒径分布对尾矿宏观力学特性及坝体稳定性具有重要影响。采用筛分法和沉降法,对82个尾矿试样进行了颗分试验,建立了细粒尾矿粒径分布的Weibull函数模型。试验结果表明:细粒尾矿粒径呈"细多粗少"的分布规律,这种规律服从Weibull分布,可以用Weibull分布对粒径分布进行描述和外推预测;传统分形模型中假设每级粒度的破碎率为常数与实际情况不符,Weibull分布可以看作对分形模型误差的一种修正;在破碎过程中,粒径的概率密度分布会出现峰值,这个峰值不断向粒径小的方向偏移,最终形成"细多粗少"的分布特点。研究结果有助于磨矿工艺的改进,并可以为土工试验做出科学的级配方案提供参考。     

Correlation between Particle Shape Evaluation Methods of Manufactured Sand

Particle shapes of different manufactured sand were tested by several methods such as uncompacted void content (UVC) test, flow time test and image analysis, the effect of particle size distribution and fineness modulus on test results were also studied,and then the correlation was analyzed. It is found that with the increase of particle sizes, flow time prolongs and UVC decreases. The correlation coefficient between flow time and fluidity of cement mortar is only 0.064 while that between UVC and fluidity of cement mortar is 0.719 3.     

Application of a Particle Swarm Optimization Algorithm in Truss Structure Optimal Design

The particle swarm optimization (PSO) algorithm developed in recent years is a stochastic optimization algorithm based on swarm intelligence. It possesses advantages such as being a simple concept, ease of implementation and low resource occupation. The PSO algorithm was adopted to solve the problem of size optimization of truss structures with stress and displacement constraints. We present the basic principle of the original PSO algorithm in detail, and then introduce a constriction coefficient to modify it. Moreover, reasonable values of the coefficients are proposed for the modified PSO algorithm. Several classical problems are solved using the modified PSO algorithm, and the results compared with those using traditional optimization algorithms and genetic algorithms. Numerical results show that the modified PSO algorithm has good convergence and stability, and can be applied to the size optimization of truss structures.     

水稻穗大小决定基因PS1的遗传分析及克隆

穗大小是影响水稻产量的重要农艺性状之一。本研究在水稻粳稻品种中花11号T-DNA插入突变体库中鉴定了一个植株略矮、穗长变短25%、一次枝梗和二次枝梗数目分别减少33%和80%、且粒型变异的突变体。T-DNA标签共分离检测表明:该突变体的表型与T-DNA插入无关。通过与籼稻品种珍汕97配置杂交组合构建遗传作图群体,F2杂合后代符合经典孟德尔遗传分离比3:1,证明突变性状受一对隐性基因PS1(Panicle Size 1)所控制。采用图位克隆的方法,将基因PS1初步定位在第11号染色体短臂上的IN44和IN50标记之间,两标记物理图距为105 kb。对候选基因进行进一步的表达量分析、比较扩增及测序发现基因LOC_Os11g12740(即SP1)可能是本研究的PS1基因。本研究为进一步分离克隆PS1基因及对水稻穗大小发育的深入研究提供依据。     

氨基酸分析仪测量水产饲料中赖氨酸的不确定度评定

分析氨基酸自动分析仪测量水产饲料中赖氨酸含量不确定度的影响因素,建立数学模型,对不确定度的来源进行分析和计算得出其扩展不确定度。当饲料中赖氨酸的含量为3.08%时,赖氨酸含量测量结果的扩展不确定度为0.020%(k=2)。     

弧形筛对水体中固体颗粒物的去除效果研究

以弧形筛为研究对象,分析不同筛缝规格、安装角度以及水处理量条件下对固体颗粒物的去除效果,以获得最优化的结构设计参数。将固体颗粒物去除率作为试验指标,设计了0.10~0.25 mm的筛缝间隙、10~20 m3/h 的进水流量及53°和37°的筛网安装角度的多因素试验。结果显示,随着筛缝间隙的增大,固体颗粒物去除率呈逐渐下降趋势,但筛缝间隙与颗粒物粒径具有明显的“匹配性”特征,筛缝间隙应以等于或略小于水体中平均固体颗粒物粒径为宜;进水流量与固体颗粒物去除率呈反相关关系,单位面积筛面的水处理负荷宜控制在50 m3/(m2?h)左右;在合理的筛网安装角度范围内,适当增大安装倾角有利于提高固体颗粒物去除率。总之,将弧形筛装置应用在水产养殖系统中,是一种行之有效的方法。     

河田鸡体重、体尺及屠宰性状测定及其相关性分析

为了探讨河田鸡体重、体尺与屠宰性状的相关关系,为河田鸡的选育提供依据。本研究对120日龄河田鸡的体重、体尺和屠宰性状进行测定,并对各指标进行了相关性分析。结果表明：体重、体斜长、龙骨长、胸深、胸宽、胫长和胫围在公母之间存在极显著差异(P＜0.01);体重与体斜长、龙骨长、胸深、胸宽、胫长、胫围均有显著或极显著正相关(P＜0.01),其余各指标间亦有不同程度的相关;宰前体重、屠体重、半净膛重、全净膛重、腿肌重、腹脂重、皮脂重、腿肌率和腹脂率在公母之间存极显著差异(P＜0.01);宰前体重与屠体重、半净膛重、全净膛重、胸肌重、腿肌重、皮脂重、屠宰率、半净膛率、全净膛率呈显著(P＜0.05)或极显著正相关(P＜0.01),其余各指标间亦有不同程度的相关。