Seismic Active Earth Pressure in Saturated Soil Subjected to Steady Seepage

To calculate the earth pressure in saturated soil mass subjected to earthquake forces and groundwater seepage,two cases,in which the seepage states are steady but the shapes of the flow lines are different,are investigated.The two cases are Case 1,in which the flow line is vertical downward,and Case 2,in which the flow line is curve toward retaining wall.Based on the pseudo-static method and Coulombs theory,the formula to calculate the seismic active earth pressures in Cases 1 and 2 is proposed.The comparison of the results with the published work indicates that the suggested formula is reasonable.The influence of the soil effective internal friction angle on the seismic active earth pressure is also discussed.The results indicate that the total seismic active earth pressure is decreasing nonlinearly with the increase of the soil effective internal friction angle.And the decrement of the total seismic active earth pressure in Case 2 is larger than that in Case 1.     

Mechanical Stimuli in Bioreactors of Cell Culturing

The bioreactors are widely used in the cell culturing in tissue engineering. For the construction of similar structure and function tissue as in vivo, people begin to adding mechanical stimuli to the bioreactor. That is not only crucial for the fabrication of engineered tissues in vitro, but also can facilitate our understanding the characters of the live tissue. The review summarizes the major approaches for cell culture, using mechanical stimuli and bioreactors. Furthermore, the suggestions on the future developing of bioreactors are provided.     

Exploration of Positive Pressure Mechanical Air Supply System

The problems are discussed in positive pressure mechanical air supply system design, when the actual status is far different from what figures in the code based. Expressions must be used to determine the supply air rate. The rate between length and width of rectangle air channel should be less than 6. To avoid some uncertain factor, correction factor for absolute coarseness should choose the bigger figure. The smoke control and extraction design of smoke controlling stair hall must be divide into two parts: The overground and the underground. When setting positive pressure mechanical air supply system in smoke controlling stair hall, the outer window in the hall must be fixed. To insure the inner surface of smoke controlling stair hall keep compact and lubricity, communion should be done with governor of builders.     

Earth Pressure on Retaining Structure of Round Deep Foundation Pit in Sand-cobble Soils

In recent years, the round deep foundation pits engineering gradually appears in Chengdu Plain whose strata are mainly sand-cobble soils. However, there are no proper calculation methods of earth pressure in retaining structure like this and distribution mode of the pressure is unknown. With the use of elastoplastic numerical simulation method involved in interaction between retaining piles and soil, the distribution law of earth pressure of the round deep foundation pit retaining structure is determined. The result shows that distribution of earth pressure on a pile is triangular and the maximum lies in the location of pit bottom, but the average value of the pressure is less than Rankine active earth pressure. Model tests have also been carried out so as to verify the distribution mode. As for the test model, the values obtained by the numerical simulation method are approximately similar to the experimental results in the distribution law as a whole, which to some degree suggests the rationality of the numerical simulation results.     

A Calculating Method of Non Linear Earth Pressure Behind Retaining Walls

Based on equilibrium analysis of forces and moment with inclined soil element, an analytical solution of earth pressure with inclined surface of fill and rough retaining wall was proposed, and the influence of slope angle of fill on earth pressure also was discussed. It is shown that the classical Rankine's earth pressure theory is a special case of the analytical solution with horizontal surface of fill and a smooth retaining wall. The results also show that the limiting rupture angle of a sliding wedge behind a retaining wall decreased with increasing slope angle of fill or friction angle between soil and a retaining wall, with the settled value of the internal friction angle of fill. The non linear character of earth pressure exhibited distinctly for the earth pressure along a retaining wall was obtained by an analytical solution. The value of earth pressure is 0 at the toe of retaining wall, consistent with the testing results. In addition, the value of earth pressure at the toe of the retaining wall will increase rapidly with increasing slope angle of fill. The analytical solution of earth pressure behind a retaining wall with fill of clay soils can be further studied with the investigative method we developed.     

干旱胁迫对夏玉米不同品种茎杆力学特性的影响

为研究干旱胁迫对夏玉米不同品种茎杆力学特性的影响,从茎杆力学特性角度探讨夏玉米品种的抗旱能力,以8个河南省主栽夏玉米品种为材料,比较干旱胁迫对茎杆抗折力、压碎强度、穿刺强度等抗倒力学指标的影响。结果表明,茎杆抗倒力学特性受干旱胁迫影响显著,平均下降15%~30%;受旱胁迫后,各品种茎杆抗折力、压碎强度、穿刺强度平均下降了26.1%、18.9%和16.8%;品种间差异明显,‘洛玉8号’、‘郑单958’降幅较小,而‘蠡玉16’、‘中科4号’降幅较大。研究结果表明‘洛玉8号’和‘郑单958’抗旱能力较强,而‘中科4号’和‘蠡玉16’抗旱能力较弱。     

Research on Mechanical Characteristics of the Cemented Sandstone Based on 3Dimensional PFC Numerical Model

Sandstone is sediment rock composed of many cemented sand particles, and corresponding particle constraint and force bearing capacity are greatly controlled by the cemented property. In order to better reflect the cemented property influencing on the mechanical characteristics of the sandstone, take the oil sandstone reservoir for instance, a numerical model based on 3Dimensional Particle Flow Code (PFC3D) considering the parallel bond model was brought forward to simulate the failure mechanism during shearing process. The sandstone cemented property is modeled based on random mathematics and advanced development of Particle Flow Code (PFC), and the relation of the stress ratio, volume strain, coordination number and bond-broken number and the axial strain is analyzed in detail, especially the contact network evolution indicated the force chain is important to transfer the external force, which verifies the feasibility of the numerical model. Based on the above PFC3D model, a series of researches on changing the cemented radius ratio, parallel bond stiffness and cemented volume of the particles have been done to clearly illuminate the importance of cemented property for the bearing capacity of the sandstone structure, which provides a scientific base for research on the failure mechanism of the sandstone under special conditions. Therefore, the above numerical method is more efficient and applicable for comparatively large scale and complex experiments, and the obtained research results can bring a new thought for the real cemented sandstone to research on its macro-micromechanical response and the structure failure mechanism, and also is significant for the sand production mechanism, sand volume prediction and sand control measures for the sandstone reservoir.     

稀土元素对酸雨胁迫小麦活性氧清除系统响应的作用

盆栽条件下,就酸雨胁迫下小麦活性氧清除系统的响应及稀土元素作用进行了研究。结果表明：酸雨导致小麦活性氧酶促系统的SOD, CAT, POD酶活性总体水平发生变化。CAT, SOD活性减弱,POD活性增加,致使体内活性氧清除能力减弱,稀土元素的施用增加了CAT, SOD活性水平,削弱了由于酸雨胁迫所导致的POD活性的增加,从而增强了清     

1980—2014年潍坊市深层地温对气候变化的响应

为了研究潍坊深层地温对气候变化的响应,利用潍坊市1980—2014年0.8~3.2 m地温资料,运用线性倾向估计、Mann-Kendall和滑动t检验等统计方法,对潍坊市近35年深层地温的变化特征进行分析。结果表明：0.8~3.2 m地温变化趋势不显著,均未发生突变,一年中,仅夏季各深层地温呈增温趋势。年代际变化上,1980s和2010s各层平均地温均高于1990s和2000s。深层地温在冬季随深度增加,稳定性渐好,夏季反之,一年中,稳定性最好和最差分别发生在夏季和冬季0.8 m地温层。气温对深层地温的影响明显,季、年平均气温与同期各深层地温多呈正相关,随着深度的增加,气温与各层地温的相关性略有降低,这是深层地温变化存在滞后性所致,降水量对各深层地温影响不大。     

Suitability of Bi-linear Restoring Force Model in Earthquake Response Analysis

Based on the data of dynamic tests of small single-storey steel frames,the suitability of simplified hi-linear restoring force model in earthquake response analysis is discussed, and the Maximum displacement response MD, the sum of squares of the displacements in the whole vibrating history SSD, and the total dissipated energy EI are considered respectively as equivalent object.     

不同机械中耕处理对人工栽培甘草生长特性的影响研究

为有效改善多年生人工栽培甘草地表生长环境,降低成本投入,提高甘草产量和经济效益,分别以播种机地表耖土、推土机地表耖土、刀具地表耖土等机械中耕为试验处理,以大田未挠动处理为对照,对比分析不同处理对甘草农田土壤水分、紧实度、地表根系呼吸、植株光合能力,以及机械中耕后对甘草株高、产量等主要特征的影响。结果表明,播种机地表耖土和刀具地表耖土均可适度改善甘草农田土壤环境、增加产量,特别是播种机地表耖土处理增产7.43%,应结合早春田间追肥、机械除草等在5月中下旬进行,推土机地表松土作业对田间甘草苗破坏严重,不提倡应用。     

响应曲面法优化高粱挤压最佳操作参数的研究

以高粱为原料,研究系统操作参数,包括:物料含水率、喂料速度、螺杆转速、机筒温度对目标参数的影响,并以响应曲面法优化最佳操作参数,优化得到的最佳操作参数为:物料含水率15.77%,喂料速度26.97r/min,螺杆转速181.20r/min,五区温度158.28℃。     

Test of Frequency Response Characteristics of Acupuncture Points in Human Ears and Correlation Analysis between the Characteristics and the Human Diseases

This paper presents a new disease diagnosis approach with a woundless testingtechnique.We fetch the data from acupoints in human ears,and then analyse their statistic and frequency response features by computsr in order to find out their characteristic functions.By studingthe correlation between these functions and human diseases,we can diagnose which disease the patient has been suffered.     

Characteristics of Interference Effects on Local Pressure of Two Square Tall Buildings in Tandem Arrangement

Wind tunnel tests were carried out to study the wind pressure on principal square building adjacent to another one in tandem. The interference effects on local pressure of the principal building were analyzed with different positions and heights of interfering building. It is shown that as height ratio is fixed, mean pressures on windward face are suctions when spacing ratio is less than 3, otherwise they are positive. The magnitudes of mean suctions on the side and leeward faces and fluctuating pressures on each face all get their maximums when spacing ratio is 3. As height ratios change, the magnitudes of mean suction on windward face increase with height ratio, meanwhile, the magnitudes on other faces obtain their minimums as the height ratio is 1.0 and the spacing ratio is less than 3. The fluctuating pressures on the windward and side faces get their maximums and that on the leeward face reaches its minimum as the height ratio is 1.0. When the spacing ratio is greater than 3, mean pressures on each face decrease, while fluctuating pressures on the windward and side faces increase as the height ratio increases, and the fluctuating pressures on the leeward face get the minimum when the height ratio is 1.0.     

水稻品种源库特性与胚乳细胞增殖和充实的关系

选用不同源库类型品种,人为改变其源库比例,观察不同粒位籽粒胚乳细胞增殖和产的反应。结果表明,强势粒胚乳的细胞增殖品种间差别不大,弱势粒胚乳的细胞增殖和充实具明显的源库类型特征。剪叶、疏花和抽穗前用氮素肥料对强势粒的影响甚小,对弱热粒影响较大。其影响首要表现在弱势粒的胚乳细胞增殖上,单细胞物质量的调节幅度较小。弱势粒粒重的提高主要通过增强胚乳的细胞增殖实现。     

the Autolisp Programming Method Processing the Data of the Function of Mechanical and Electrical Products

This paper has briefly stated the necessit of applying the computer to processing automatically the data of the function of mechanical and electrical products. It has also presented the method which can solve this practical problem. The method is AutoLISP programming design. Besides, It has summarized the features of LISP and A oLISP language and the principles of the AutoLISP programming method. With examples.     

A Sort of Method of State Space Search in Mechanical Translation

There is a kind of combination of correlated objects in mechanical translation.When match the combination with the rule,the searching solution becomes un-possible by the"combinatorial explosion".A hierarchical intelligence search method is advanced.According to the prior knowledge,the data which do not satisfy the correlation constraint will be removed by the closed-loop eliminate method at first and then only a simple search in order is needed for obtaining the solution of the problem.This method refrains from any backtracking.The time and space consumed by search are greatly reduced.     

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.