Subsoiling and deep fertilizing with new technique as a measure of soil conservation in ag agriculture,viniculture and forestry

Compacted soils have low infiltration capacity. As a consequence, the danger of soil erosion by surface-runoff is high. Subsoiling may be an effective countermeasure. Deficiencies of previously existing subsoiling techniques (lift-loosening) gave reason to develop a new technique of soil melioration. Some effects of this new multiple purpose break-off subsoiling on soil physical properties and yields, advantages and possible areas of use are described.     

Time Effect Experimental Analysis of the Soil Arch Effect of Anti sliding Pile

Soil arching effect is important for stabilizing the soil behind anti sliding pile. The creep of soil mass will inevitably lead to the formation of soil arching, which has time effect. In this analysis, an indoor thrust pile model test is proposed. The characteristics of stress distribution in the soil and the time effect of soil arching behind anti sliding pile are analyzed. The experimental data acquired by the soil pressure cells arranged along the normal direction of the thrust show that soil arching effect is enhanced with the increase of thrust.The thickness of soil arch increases with time.And the data obtained by soil pressure cells arranged along the direction of the thrust show that the horizontal soil arching effect increases and then gradually extends.The scope of stress dispersion has very large growth along the normal direction as time goes on.     

Using a computed tomography miniscanner for studying tillage induced soil compaction

Gamma-ray computed tomography (CT) is used to study thin compacted soil layers, such as millimeter thick “blades” that occur at plowing depth. The technique has the advantage, over the traditional gamma-ray attenuation techniques, of opening the possibility of measuring water contents and bulk-densities of odd-shaped samples. Being a 2-or 3-dimensional technique it is possible to detect small change of bulk-density and soil water content within the sample, even in thin layers of the order of millimeters. Results are reported for thin compacted layers in soil samples collected at the plowing depth from sugar-cane fields in Brazil, which clearly demonstrate the usefulness of this new method for compaction investigations and its quantitative evaluation.     

食品行业粉体材料流动性研究的新仪器——PFT

奶粉、面粉、糖、盐、调味品等原料和添加剂粉体的流动性研究是目前很多材料行业的难点,现有常见的一些方法不能满足实际的需求。简单介绍了Brookfield公司根据ASTM D 6128推出的PFT粉体流体测试仪的基本功能,介绍了粉体流动函数、壁面摩擦、松装密度、时间固结、拱架、鼠孔、料斗半角的测量和计算。     

牛蒡、大豆、大蒜提取物提取工艺的优化

为了优化植物提取物的提取工艺,采用水浸提的方法研究了牛蒡、大豆、大蒜提取物的提取工艺。选取固液比、提取温度、提取时间等3项考察因素,采用正交实验对提取条件进行优化。实验结果表明：影响提取率的主因素综合来说是提取温度。其中,对于牛蒡来说,最优的提取工艺为：固液比1：20（重量比）,提取温度70℃,提取1小时。对于大豆来说,最优的提取工艺为：固液比1：10（重量比）,提取温度70℃,提取1.5小时。对于大蒜来说,最优的提取工艺为：固液比1：20（重量比）,提取温度90℃,提取2小时.     

Frost Heave Tests for the Bedding Materials of Face Rockfill Dam in Pushihe, P. R. China

To insure the safe performance of rockfill dam faces in cold seasons, frost tests were carried out at a consistent empirical freezing speed of 20mm/day to study the frost susceptibility of the bedding materials. The influence of gradation, fine particle content, water content, and surcharge of the bedding material on frost heaving were obtained. When fine particle content was below 12%, there was no or only weak frost heaving. Frost increased linearly as fine particle content rose. When the fine particle content was fixed, the linear relationship between the water content and the frost heaving changed with the gradations. Typical water content of 7.5%, fine particle content of 12%, and concrete face density of 59g/cm3 are suggested for the bedding material to avoid frost damage.     

原生质体技术在园艺植物育种中的应用

原生质体技术包括原生质体植株再生、原生质体融合技术等,在园艺植物育种应用工作中取得了一定的成果,原生质体再生植株的变异为园艺植物育种工作提供了大量材料;原生质体融合技术则是育种工作的新途径。二者都对育种工作的发展起到了非常重要的作用。     

Large Dams,Restructuring and Regional Integration in Southeast Asia

Large dams are a dramatic intervention affecting ecosystems, livelihoods and resource use, notably in upland areas. Dams are significant, both in terms of their scale of impact and due to their role in appropriating part of the upland resource base for mainly lowland and urban beneficiaries. Whereas in the past the tensions associated with impact of dams in Southeast Asia have been played out within national borders, mainly in Thailand, the new impetus for dam construction reflects an internationalised agenda — namely integration of the mainland Southeast Asian regional resource economy. This paper examines the background to large dam construction in mainland Southeast Asia, current and projected developments, and their implications in a number of arenas. Case studies from Lao PDR, Thailand and Vietnam illustrate the main points. It is shown that political­economic restructuring associated with the changing geopolitics of the region is a major influence on the revived agenda for large dam construction, and that such restructuring modulates the direct and indirect impacts of dams at local, national and regional levels.     

青椒果实采后病害及控制技术研究进展

青椒果实因水分含量高和采后代谢旺盛,贮藏期间极易受到病原菌的侵染,严重影响了青椒的贮运品质和商品价值。总结了青椒果实采后的细菌性和真菌性病害,分别从物理、化学和生物保鲜技术3个方面介绍了青椒采后病害的主要防控手段,并进一步阐述了各类防控技术的作用机制,以期为青椒采后病害控制提供参考借鉴。     

Finite Element Analysis of the Influence of Steel Strength on Beam-to-column Composite Connections

Because high material strength and composite load-bearing are emphasized in constructing members for high-rise steel frame structures, in a composite connection, steel strength has a dramatic influence on both the bearing performance and the composite action of the concrete slab. Based on a finite element analysis, we discuss the composite effect and the connection breaking mode, focusing on the performance change of the composite effect in adopting high strength steel. It can be found from the results that, along with the improvement of the steel strength, the elastic and plastic ultimate strength of the composite connection will increase, the ductility will decrease to a certain extent, and the composite effect of the concrete slab will diminish. The collapse of the concrete in a positive moment side contacting the column flange is viewed as the limiting state of the connection.     

广元市农产品加工业发展对策探讨

在分析广元市农产品加工业现状及主要问题的基础上,从农产品基地建设、龙头企业培育、市场运销、政策、科技、资金和人才等方面提出对策建议,以促进农产品加工业的发展,着重指出粮油、果蔬、肉、乳、茶叶、干果等农产品加工的具体项目。     

DEM Study of Flow Pattern of Powder Compacted

Discrete Element Method(DEM) is used to study the flow pattern of loose powder which is indented by a rigid punch in an open die.Information such as trajectories or velocity of the particles movement and density distribution of the granular material during compaction is obtained.Typical powder flow characters in given areas can be observed in the theoretical simulation and experiment.It demonstrates that DEM can capture the major features of the powder flow behavior under low-pressure compaction when there is intense shear,and the conclusion of the flow behavior of compacted powder is useful to the industrial designing.     

Theoretical Analysis and Testing of Ground Treatment Using an Expansive Method in Very Thick Collapsible Loess

Through technological research of foundation treatments in the collapsible loess areas, we recommend a method of treating foundations in collapsible loess with quicklime piles. We set forth the basic principle of this expansive method. When a very thick foundation in collapsible loess is treated, the computational formula for the volume of expanding material in a quicklime pile is deduced based on cavity expansion theory. This theory is applied to engineering practice. Physical and mechanical properties of the compacted soil are tested. The result shows that the collapsibility of a foundation in loess has been eliminated, its physico mechanical indexes have been improved, and the soil compressibility and the modulus of compressibility also increase remarkably, demonstrating the correctness of the computation theory. The feasibility of the expansive method for very thick collapsible loess areas is further established.     

Varietal Differences in Development of Maize (Zea mays L.) Seedlings on Compacted Soils

Differences among open-pollinated tropical maize ( Zea mays L.) varieties in seedling development and establishment on compacted soils were studied. Soil dry density was used as an index of compaction. Three soil compaction levels and 12 traits associated with development and establishment of maize seedlings were investigated. A control (without compaction) was also included. Varietal differences were observed for most traits measured. Genetic differences for seedling development on compacted soil were detected. Varietal differences contributed about three times the contribution of compaction to total variability in the traits. Better seedling development and performance were obtained in moderately compacted soil than in the control. Shoot length, shoot dry weight and per cent dry matter in roots were good indicators of the tolerance of maize seedlings to compaction. A physiological strategy for maize seedling establishment on compacted soil was proposed. The implications of the results for seed testing were also highlighted. It was concluded that consideration should be given to the genotype of maize destined for use in ecologies prone to high soil densities. All varieties of maize grown in an agroecological zone could be screened to identify genotypes tolerant of higher soil densities. The seeds could then be multiplied and distributed to farmers.     

Experimental Study on the Compressive Property of Luojiashan Clay

This paper carried out an experimental study on the compressive property of Luojiashan Clay at Wuhan University. In order to investigate the influence of compaction degree, compaction water content and saturation state of compacted soil on the compressive property of clayey fill, compression tests were done on the samples compacted to different water content around optimum moisture content by different degrees of compaction. The theory of compacted soil structure was used to explain mechanism of the influence, and it was the change of soil structure that caused the variation of compresSive property. The results of the tests show that it was at agiven range of stress that degree of compaction and compaction water content have influence on the compressive prop- erty of clayey fill. Around optimum moisture content with degree of compaction decreasing or compaction water content increasing, the compressive deformation of clayey fill increased. When compacted fill was saturated by water soaking, the compressive deformation increased much, and the clayey fill compacted at greater water con- tent than optimum moisture content showed smaller compressive deformation caused by saturation at other conditions the same.     

DEM Analysis of Soil Arching of Pile Supported Embankment

Pile supported embankment has been widely used in road, airport and dam engineering due to effective construction and economic advantages which can effectively control the settlement and differential settlement. The soil aching effect is a key factor in the load transfer mechanism of pile supported embankment. Based on the current laboratory model test, a series of numerical simulations were conducted with the particle flow code PFC2D to study the contact force, principal stress, vertical and lateral displacements in embankment. The embankment fill and subsoil were simulated by the Disk,andthe pile and model box were simulated by the WallThe multi-layer compaction method was used to establish the Discrete Element Method models. The micromechanical properties of the embankment fill and subsoil were obtained from numerical biaxial compression test and simple compression test, respectively. The simulation results indicated that the soil arching in pile supported embankment was composed by multiple hemispherical arches with different centers, and the height of arching was about 5(s-a)/6. Within the soil aching height, the deflection of principal stresswas obvious, and the vertical and lateral displacements were significant.     

The Mechanism Analysis of Anti clogging Arching Structure in Dredged Sludge

A number of lands were occupied by discarding the dredged sludge in the yard as waste materials.The Aeration Vacuum rapid Mud Water Separating (AVMWS) technique was appropriate for discarding yard with high water content and high clay particle content sludge.This technique could quickly reduce the volume of the sludge and accelerate the turnover use of the yard.In addition,the technique could overcome the clogging problem when pumping water from high water content, high clay particle content dredged sludge.Through the sampling particle size distribution tests after AVMWS and conventional vacuum pumping model tests, it was found that in the AVMWS tests the fine grained soil run off, coarse particles accumulated, and arching structure layer was formed.However, in the conventional vacuum pumping tests, fine particles did not lost and there was clogging without arching structure layer.The layer could protect the internal loss of the fine particles and ensure a high permeability of the soil at the same time.And the mechanism was explained as well.     

果蔬速冻技术、设备和质量控制现状分析

果蔬速冻产品因卫生、新鲜、方便、保质期长等而受到消费者的青睐,并成为我国农产品消费和出口的重要类别。本文综述了我国果蔬速冻加工的现状、发展,论述了果蔬速冻的原料选择、预处理、冻结等关键工艺,介绍了目前果蔬速冻广泛应用的隧道式连续速冻装置、流态化单体速冻装置、流化床式速冻装置等设备特性;同时探讨了果蔬速冻质量控制的管理要点和注意事项,并对我国果蔬速冻的发展前景进行了展望。     

Face Stability Analysis of Shield Tunneling in Sandy Cobble Stratum

When shield crossed the sandy cobble stratum in Chengdu metro line 1, ground subsidence reached as high as dozens of times. The losing stability of excavation face caused excessive ground loss. Conditions of engineering geology and hydrogeology about sandy cobble stratum in Chengdu were analyzed. Mechanical characteristics of sandy cobble were obtained via large-scale triaxial test. According to the low cohesion and heavily discrete characteristics of sandy cobble, numerical computation was conducted by discrete element method. Based on numerical simulation of the large scale triaxial test, the micro parameters of the sandy cobble were calibrated. The influence of support pressure on shield excavation face deformation, surface settlement, max horizontal displacement and stress of soil was analyzed. The results show that: 1) Collapse pattern of excavation face by numerical simulation coincides with result of centrifuge model test in sand. 2) When supporting pressure is small, contact forces of particle in front of excavation face is low. The tendency of particle flow is apparent. Since over-excavation is easily brought out, cavity in the ground is caused after shield tunneling. 3)Soil arching effect in shield construction is obvious. Shield excavation forms cavity in deep ground and obvious earth surface collapse is not observed. This is main reason for lagged settlement phenomena of shield tunneling in Chengdu.