利用线性规划确定贮木场最佳产品结构

满足用户的需要是贮木场的宗旨,最大的获取利润是贮木场重要目的之一。我国是少林国家,而木材利用率又十分低,然而我国贮木场多为原条、原木调进,又以原木(这是主要的)调出。这不仅减少了收益,又满足不了市场日益增加对林产品的需要。那么如何既能满足市场的需要,又能获取最大的利润呢?这就是如何选择合理的产品结构问题。决定产品命运的是原料、生产和市场这三个基本要素。

取灯儿

取灯儿(qǔdēngr),北方地区火柴的俗称,《辞源》记载:"华北地区旧时称火柴为取灯儿。""在竹片或松木片上涂硫磺,用来点火。"道光年间,火柴传入我国,人称"洋火",取灯儿便叫洋取灯。在北京前门大栅栏附近,有一条古老的胡同,总长不过百余米,看着其貌不扬,但它却是最原始的火柴发源地,名称就叫取灯胡同。取灯胡同最早形成于明代,当时取灯作为取火工具已进入商品市场,北京城就有人以此为业。后来,制造、贩卖取灯的人越来越多。

Constitutive Model of Saturated Soft Clay with Cyclic Loads under Unconsolidated Undrained Condition

An equivalent visco-elastic model of saturated soft clay was studied under unconsolidated undrained (UU) condition, which can be used to evaluate the stability of ocean foundation. Cyclic triaxial compression and extension tests were conducted to study the parameters of the model. Results showed that the relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain were nearly unique, when the initial octahedral shear stress ratios of specimens were equal to 0.3, 0.5 and 0.7. The relationships of the damping ratio and the octahedral shear modulus with the octahedral cyclic shear strain determined from the cyclic triaxial compression tests were basically the same as those determined from the cyclic triaxial extension tests. Furthermore, the relationships were not related to the initial stress condition, the test stress state and the octahedral cyclic shear stress ratio. The relationships determined from the cyclic triaxial tests under no deviatoric stress were basically the same as those determined from the cyclic triaxial tests under deviatoric stress. The change of the octahedral cyclic accumulative strain with the number of cycles was unique under different tests stress states. An equivalent visco-elastic constitutive model of saturated soft clay under UU condition was initially established.

Prediction of oxygen concentration and temperature distribution in loose coal based on BP neural network

An effective method for preventing spontaneous combustion of coal stockpiles on the ground is to control the air-flow in loose coal. In order to determine and predict accurately oxygen concentrations and temperatures within coal stockpiles, it is vital to obtain information of self-heating conditions and tendencies of spontaneous coal combustion. For laboratory conditions, we designed our own experimental equipment composed of a control-heating system, a coal column and an oxygen concentration and temperature monitoring system, for simulation of spontaneous combustion of block coal （13-25 mm） covered with fine coal （0-3 mm）. A BP artificial neural network （ANN） with 150 training samples was gradually established over the course of our experiment. Heating time, relative position of measuring points, the ratio of fine coal thickness, artificial density, voidage and activation energy were selected as input variables and oxygen concentration and temperature of coal column as output variables. Then our trained network was applied to predict the trend on the untried experimental data. The results show that the oxygen concentration in the coal column could be reduced below the minimum still able to induce spontaneous combustion of coal - 6% by covering the coal pile with fine coal, which would meet the requirement to prevent spontaneous combustion of coal stockpiles. Based on the prediction of this ANN, the average errors of oxygen concentration and temperature were respectively 0.5% and 7 ℃, which meet actual tolerances. The implementation of the method would provide a practical guide in understanding the course of self-heating and spontaneous combustion of coal stockpiles.

Effects of Subsoiling on Some Soil Physical Properties and Wheat Yield in a Dry Land Ecological Condition

In order to evaluate the effect of subsoiling on the soil physical properties and wheat yield in dry land conditions, this research was conducted in Mamassani area of Fars province in Iran. The experiment was laid down in the form of a complete block experimental design with four treatments and four replications for three years. Treatments included： （1） conventional tillage without using subsoiler which was control treatment （So）; （2） using subsoiler with the shank space of 40 cm which was equal to the subsoiling depth （SO; （3） using subsoiler with the shank space of 60 cm which was 1.5 times of the subsoiling depth （S2）; and （4） using subsoiler with the shank space of 80 cm which was 2 times of the subsoiling depth （S3）. Subsoiling depth was set at 40 cm which was the lower limit of the hard pan depth in the soil. Soil cone index, soil bulk density, soil moisture content, wheat yield, and yield components were measured in this study and SAS software was used to analyze the collected data. Results showed that subsoiling decreased the soil bulk density and cone index, and increased water retention of the soil. Results also revealed that applying subsoiler increased wheat yield and yield components in our dry land conditions. Since subsoiling improved soil physical conditions and increases wheat yield, applying subsoiler in such a dry land conditions is therefore recommended. Results of this study also showed that subsoiling with the shank space of 40 cm and 60 cm had better performance compared to the shank space of 80 cm. On the other hand, shank space of 40 cm reduced the subsoiler effective working width and consequently effective field capacity. Therefore, subsoiler with a shank space of 60 cm is recommended for application in dry land soils of our type.

Statistics and Correlation Properties of Diamagnetic High Rydberg Hydrogen Atom

The spectra of Rydberg hydrogen atom in magnetic fields have been calculated using linear variational method with B-splines basis functions [Acta Phys. Sin. 55 （2006） 3380]. Based on these calculations we have done some statistics analysis about the high Rydberg energy levels. The nearest-neighbor energy spacing distribution and the 3-statistics have been shown about diamagnetic Rydberg hydrogen atom with the magnetic field being 0.6 T and 6 T. The phenomena of multiply crossing, multiply anti-crossing, and the mixed of crossing and anti-crossing of energy levels have appeared in this paper. For both cases, in range of lower energy, the energy 1evel statistics properties close to Poisson distribution. With the increasing of the energy, the energy level statistics properties are away to Poisson distribution and tend to Wigner distribution step by step.

Backward Doubly Stochastic Differential Equations with Jumps and Stochastic Partial Differential-Integral Equations

Backward doubly stochastic differential equations driven by Brownian motions and Poisson process （BDSDEP） with non-Lipschitz coefficients on random time interval are studied. The probabilistic interpretation for the solutions to a class of quasilinear stochastic partial differential-integral equations （SPDIEs） is treated with BDSDEP. Under non-Lipschitz conditions, the existence and uniqueness results for measurable solutions to BDSDEP are established via the smoothing technique. Then, the continuous depen- dence for solutions to BDSDEP is derived. Finally, the probabilistic interpretation for the solutions to a class of quasilinear SPDIEs is given.

Stochastic Cahn-Hilliard equations driven by Poisson random measures

We study a stochastic Cahn-Hilliard equation driven by a Poisson random measure with Neumann boundary conditions. The global weak solution is established for the equation. Moreover, the existence of a Lyapunov function for the equation and an invariant measure associated with the transition semigroup are proved.

Therapeutic effect of heat-sensitive moxibustion plus medications for senile osteoporosis and its effect on serum BMP-2 and OPG levels

Objective:To observe the clinical efficacy of heat-sensitive moxibustion plus medications on senile osteoporosis(SOP),and to explore the related mechanisms.Methods:A total of 70 elderly participants with osteoporosis were randomly divided into an observation group and control group,with 35 cases in each group.The control group was treated with conventional drugs,and the observation group was treated with heat-sensitive moxibustion on the basis of the conventional drugs.Both groups were treated for 3 months.Before and after treatment,assessed the visual analog scale(VAS)and Oswestry disability index(ODI)scores,determined the bone mineral density of the participants'lumbar spine(L2-L4)and left femoral neck,and detected the participants'serum bone morphogenetic protein-2(BMP-2)and osteoprotegerin(OPG)levels.Results:After treatment,the VAS scores of both groups were lower than before treatment(both P<0.05),and the VAS score of the observation group was significantly lower than that of the control group(P<0.05).After treatment,the bone mineral density values of the lumbar spine and left femoral neck in both groups were significantly higher than before treatment(both P<0.05),and the bone mineral density values of the observation group were higher than those of the control group(P<0.05).After treatment,the ODI scores of the two groups were lower than those before treatment(both P<0.05),and the ODI score of the observation group was lower than that of the control group(P<0.05).After treatment,the serum BMP-2 and OPG levels in the observation group were significantly higher than those in the control group(both P<0.05).Conclusion:Heat-sensitive moxibustion plus medications for SOP can significantly relieve patients'pain,improve dysfunction,and increase bone density,which may be related to the improvement of the serum BMP-2 and OPG levels.