重庆茶叶污染途径研究

调查区域土壤环境质量符合NY/T 391-2000《绿色食品产地环境技术条件》标准,75%的土壤样本符合NY 5199-2002《有机茶产地环境条件》标准,土样中六六六和滴滴滴均未检出,研究区域茶叶产地环境质量优良。对茶叶所检指标六六六、滴滴涕、铜、铅,按NY 5017―2001《无公害食品——茶叶》进行评价,鲜茶叶样本超标率为0,成品茶叶样本超标率为11%,污染物为铜。按NY 5196―2002《有机茶》标准进行评价,鲜茶叶样本超标率为95.2%,超标污染物为六六六和铅,六六六检出率为95.2%,铅超标率为9.5%。成品茶叶样本超标率为100%,六六六检出率为89%,铜超标率为61%,铅超标率为50%。生产过程农药的不合理使用是造成成品茶叶中农药六六六超标的主要原因,加工过程不清洁是造成成品茶叶中重金属铅、铜超标的主要原因。     

Application of Modflow in Sustainable Exploration of Geothermal Water at Xaoquan of Chongqing

On the basis of sufficient discussion of hydrogeologic condition of geothermal water in the Xaoquan area, authors a mathematical is studied with MODFLOW model is established, and then the geothermal water is studied with MODFLOW program. Andthe mathematical model is identified. The authors compare the simulative water level with actual water level. The MODFLOW program can study geothermal water,when the simulative water level approximated to actual water level, and the mathematical MODFLOW model is right. Geothermal water under condition of different exploitation is stndied with the MODFLOW program. Sustainable exploitation is achieved.     

不同条件下粮食油料散落性的探讨

利用传统的木板法和固定漏斗法测定不同水分、杂质大豆、稻谷和油菜籽在不同材料上的自流角、静止角。结果表明:不同含水量的稻谷,随着含水量的增加,其自流角在增大;不同杂质含量的稻谷,随着含杂量的增加,其自流角在增大;不同材质的板材,随着摩擦力的增加,其自流角也在增大。不同含水量的稻谷,随着含水量的增加,其静止角在增大;不同杂质含量的稻谷,随着含杂量的增加,其静止角也在增大。相同水分的大豆、稻谷、油菜籽,稻谷的摩擦力最大,自流角和静止角也最大;大豆、稻谷、油菜籽相比,大豆粒大、饱满、表面光滑,油菜籽次之,因此,在外界条件相同情况下,大豆的散落性最好,油菜籽次之,稻谷最差。     

Performance Comparison of High Strength Concrete Prepared with Metakoalin and Silica Fume

This paper makes a comparison of high strength concrete prepared with Metakoalin and that prepared with silica fume in terms of their workability, compressive strength , shrinkage and resistance to sulphate attack. The research results indicate that high strength concrete prepared with Metakoalin is better than that prepared with silica fume in terms of workability. When the water to binder ratio is high, concrete prepared with Metakoalin has a greater compressive strength than that prepared with silica fume. In contrast, when the ratio is low, it is the concrete prepared with silica fuma has a higher strenth. Concrete prepared with Metakoalin has a smaller auto -shrinkage and dry-shrinkage than that prepared with silica fume. And concrete prepared with Metakoalin will be just as good as concrete prepared with silica fume in terms of resistance to sulphate attack. It is indicated by the research that Metakoalin has same high activity as silica fume in the preparation of high strength concrete.     

A Method of Simulation of Squirrel-cage Motors with Rotor-rar and End-ring Faults

In this paper,a method used to simulate the squirrel-cage motors with rotor-barand end-ring faults is presented. In our analysis,the stator is still represented by three-phase windings,but each loop of the rotor is considered as a single-phase winding,so it is convenient to describethe situation of the motor with any number of broken rotor-bar and end-ring.Compared with othermethods,the method of this paper can be used to analyse both the steady-stats and the transient stateof cage motor with rotor faults.     

A Design Method for Composite Ply Containing Preformed Hole

A iteration method for the orientation and the distribution of fibers in a composite ply with a pre-formed hole is proposed, which is based on the FEM analysis and the corresponding criterion of strength and continuous condition of fibers. It is shown that, there is marked increase of the load carrying capability compared with that of the ply with a drilled hole. The obtained result can further be extended to the design of composite laminate with pre-formed holes.     

考虑渗流和地震时的砂土边坡稳定性计算

基于极限平衡理论,以砂土边坡为研究对象,推导了渗流和地震存在时拟静力法和拟动力法边坡安全系数的计算表达式。通过程序求解,与已有算例对比表明,计算结果基本一致,验证了2种方法解析式的合理性。参数分析表明,水位越高,边坡失稳越严重,水力梯度与安全系数基本为线性关系。渗流方向向下时,稳定性随水力梯度的增加而增大;渗流方向向上时,变化规律相反。水平地震加速度系数对稳定性的影响剧烈,竖向地震加速度系数对稳定性影响较小,简化计算可以忽略不计。最终得出拟静力法的解析式,简单、实用,而拟动力法则可以更为全面地考察砂土边坡稳定性随时间变化的特点。     

烤烟早熟品种PVH19引种试验初报

为研究巴西引进烤烟早熟品种PVH19在云南烟区的品种表现,在云南省16个地点对该品种进行引种试验,各试验点均采取随机区组排列,3次重复。综合引种试验结果,烤烟品种PVH19株式塔型,打顶株高103.5cm,有效叶数20.6片,叶形长椭圆形,茎叶角度中等,主脉中等偏粗,田间整齐度高,成熟性好,田间长势较强;平均大田生育期111.9d,比对照K326短11d;经济性状与对照K326相近;中抗黒胫病和赤星病,抗TMV,烤后原烟颜色桔黄,光泽度适中偏强,油分中等,叶片结构疏松,叶片厚度适中偏薄,外观质量较好,内在化学成分协调。结果表明：烤烟品种PVH19早熟、适应性广、综合抗性好、优质、适产     

Discussion of the Negative Thermal Expansion Coefficient of the Laminar Crystal

The variation of the thermal expansion coefficient of the graphite crystal is derived. According to the theory of temperature with the thermodynamic and statistical physical, the free energy of the graphite crystals is given with the De-Bye Model, and relationship between the thermal expansion coefficient of the graphite crystal and the temperature range is probed. The results are showed: the thermal expansion coefficient is equal to zero if T =0 K or T is on the verge of the 15 K or 42 K; negative if the temperature is in the range of 15 to 42 K; constant if the temperature is higher. The theoretical calculations accord with the experimental results. From this, In the layered crystals the reason that there is the negative expansion is that the statistical weight of the transverse acoustic vibration for the atoms in the plane layer is very large. In some temperature ranges, the variation of distance between atoms in the direction perpendicular to the plane layer with the temperature resulted in by the transverse acoustic vibration reverses with that in the plane layer. Then the film effect is resulted in.     

Bi-level Programming Model and Genetic Algorithms for the Selection of Vendors

The traditional vendor selection model often pay attention to the profit of the buyers and the selection behavior of vendor is ignored,but the vendors only trade with the buyers according with their rational selection,so the vendors selection bi-level programming model is presented with constraint of minimal batches,the ability of supply,product matching etc.A solution of the model based on genetic algorithm is proposed.The buyers' vendor selection of minimum cost is realized in the upper programming and the allocation of requirements is proposed in the lower programming.The application of the model and its algorithm are illustrated with a practical example.     

Fault Line Selection for the Distribution System with the Adjustable Arc Suppression Coil

The problem of the faulty line selection with the arc suppression coil(ASC) has existed for a long time.On the basis of analyzing the relationships between the ASC admittance and the admittances of lines,including the faulty line and non-faulty lines,the calculation of the b parameter is presented,in which the state of the ASC is changed during the single-ground existing for the faulty line selection by adjusting its inductance.The value of b for the faulty line is much greater than that for non-faulty lines in both the direct ground and the ground with the resistance.The proposed method is verified with the simulation and is applied to the projection.It is proven that the proposed method is with the high reliability.     

Analysis on Lawful Elusion of Contracting with Own Capital in Construction Engineering

At present, the construction market in China lies in some disordered condition and there are lots of unlawful cases, contract with own capital is one of them. In this paper, the conception of contract with own capital is defined and its harmness is analyzed. Then, four forms of contract with own capital in the real life are introduced. At the same time, the reason why it is unable to be forbidden in China is analyzed. In the end, the authors put forward their suggestions.     

Analysis of diffusion equation with the second and third boundary conditions based on steady state approximation

One dimensional diffusion equation is widely used to describe mass transfer in particles or droplets in a reactor. The length of the definition domain of the one-dimension Fick equation is limited, because it is determined by the scale of the particles or the droplets. The diffusion equation with a certain length of definition domain has no analytic solution unless series solution. So, to obtain approximate solutions of diffusion equation is of theoretical significance and practical significance. Firstly, assumption of constant concentration variance ratio is used instead of assumption of constant concentration frequently used in kinetics of process metallurgy. Secondly, a detail process to deal with diffusion equation based on steady state approximation is given, and the approximate solutions of the diffusion equation at certain conditions are obtained at the same time. By comparing the approximate solutions with the numerical solutions, it is concluded that the diffusive process of non-steady state is considerably well predicted by the approximate solutions, and approximate solutions accord with the situations being close to the final steady state a little better than accord with the situations being close to the begin of the diffusion, and it fairly satisfies the total mass balance.     

Point Force Model of Smart Structure Piezoelectric Actuator With Paste Layer

In the smart bar-beam structure with piezoelectric strain actuator active control function to vibration, the thickness effect of paste layer is considered and strain is assumed linear distribution along the thickness direction of each layer. The piezoelectric actuator point force model of Crawley and Luis is refined, a more general point force model is established to the smart beam with strain actuator. Point force model calculation formula is educed to smart beam with two-side symmetry paste actuator or one-side paste actuator. The computer simulation is done and the result reveals modified point model is right. The modified model is more common, as is important to design piezoelectric smart structure.     

Conjugate Natural Convective Heat Transfer in an Enclosure with Discrete Protruded Heat Sources

The mathematic model on natural convection is proposed in a two-dimensional enclosure cavity with an isothermal heat sink at one vertical wall and five discrete protruded sources. Numerical study is performed to analyze the natural convection in the enclosure with a variety of aspect ratio, the range of which is from 3.0 to 12.22, Ra H is 10 7 and Pr is 30.The computed results show that the total heat transfer effect under the situation with discrete protruded heat sources is prior to that with flat wall heated. Moreover, when the aspect ratio is comparatively large, there is several secondary flow in the enclosure, which enhance the convective heat transfer. On the contrary, when the aspect ratio is small, the secondary flow weakened or disappeared, and the total convective heat transfer drop. Finally, the convective heat transfer criteria in the enclosure is obtained.     

Application of Hydraulic Torque Converter Incorporated in Mechanical Continuously Variable Transmission

Continuously Variable Transmission which is the ideal transmission for automobile can improve dynamical and economical performance and reduce pollution emission effectively. Vehicle equipped with CVT where hydraulic torque converter is acted as start clutch have better acceleration performance and its starting control is very simple. Based on performance test of hydraulic torque converter and simulation on lock-up dynamic process of torque converter clutch, matching characteristic between engine and torque converter is evaluated , and the lock-up control rule of torque converter clutch and the control strategy of standing start of vehicle equipped with Continuously Variable Transmission with torque converter is proposed. By computer simulation on start process, vehicle equipped with CVT have better acceleration performance than equipped with five-speed MT.     

Simulation optimization for input plan of multi type and batch production with flexible process

Aiming at multi type and batch production system with flexible process, an optimization method for input plan based on Witness simulation is proposed. The scientific problem researched is described. Aiming at the characteristics of multi type and batch production with flexible process, the simulation logic is designed. Taking Witness as simulation platform, the simulation model combining input plan with scheduling for multi type and batch production is constructed. The effectiveness of the method is tested by simulation examination.     

Multi-Step Iterative MUD Technology for TD-SCDMA System

Joint Detection technology is a hot point in the research of TD-SCDMA system. Because of a SNR degradation, JD can not reach the need of system performance when system loads is close to the spread factor. MSJD and iterative multi-user detection are put forth to overcome the problem. When iterative MUD is adopted, the research shows that system performance is close to single user performance after 3 iterations, but its computational complexity grows exponentially with the number of code channel. When MSJD is adopted, complexity is reduced compared with iterative MUD, but system performance of code channels numbered K is only close to system performance of code channels numbered K/2 as JD is used. Considering computational complexity and system performance, multi-step iterative multi-user detection technology is brought forth based on iterative MUD and MSJD. According to simulation, the result can be concluded that complexity is reduced compared with single iterative MUD and system performance is improved compared with single MSJD.     

Data Collection Based on Web Services

To construct data warehouse with heterogeneous, self-governing and distributed database system is a challenge. Two problems have to be solved: one is how to collect data from heterogeneous data sources by an effective method, the other is how to clear up and change the format of the data collected from data sources. The opening and the interact-operation property of Web Services is Analyzed. A Data Collection System based on Web Services, which communicates with heterogeneous data sources with SOAP and HTTP, has been designed. A Data Collector is introduced to clear up and to transform data with composition technology. The pivotal XML technology of transforming and loading up the data are discussed.     

Physical simulation of production performance of fractured horizontal wells in low permeability reservoir

For the fractured horizontal wells with spindle and dumbbell-shaped distribution of fracture in the Changqing oil-field, 3-D scaled physical models are utilized to simulate their production performance in elastic drive and waterflooding. The experimental results indicate that the oil production and the experimental time of two models are closely exponential function. The oil production of the horizontal well with dumbbell-shaped fracture is higher, but its decline rate is faster. The productivity formula and material balance equation of closed reservoir with elastic drive are utilized to derive the exponential form of oil production. Influence factors of oil production and its decline rate are analyzed in elastic drive. In waterflooding, the water breakthrough time of the horizontal well with spindle fracture is later than the one with dumbbell-shaped fracture. And the rate of water cut increasing of the model with spindle fracture is slower. In the initial stage of waterflooding experiment, elastic drive is still the leading position, so the oil production of the model with dumbbell-shaped fracture is higher. When the cumulative water injected exceeds 0.2 PV, the recovery percent of the model with spindle fracture is higher than the one of the model with dumbbell-shaped fracture. When the percent water cut reaches 98%, the recovery percent of the model with spindle fracture is 33.67%, while the one of the model with dumbbell-shaped fracture is 27.48%.