高大平房仓屋面喷水降温试验报告

进入夏季，外温不断升高，仓房受热主要来自仓顶，由于仓房屋面所受到的太阳辐射量大，传热速度快，导致拱板上弦空间温度有时高达50℃。新建平房仓上弦表面虽进行了隔热处理，但达不到理想的效果，仓温也高达38℃，直接加速了上层粮食品质的陈化。因此屋面的隔热、散热，对低温安全储粮至     

大跨度犰狳——薄壳结构棚建设

正犰狳结构是仿生技术,建筑的外壳犹如穿山甲身上的鳞片在紧绷状态下形成整体,非常结实,具有一定的整体抗压力。而在放松状态下鳞片彼此独立,灵活性很好。薄壳技术同样是仿生技术,就是利用如鸡蛋壳一般弧形形状,在同等材质情况下,薄壳结构抗压力最强。这两项技术的结合,即犰狳——薄壳结构棚建设核心技术。利用钢管,内穿钢丝。钢管使用弯管机弯出一定弧形,在钢管两端使用专业的紧绳和锁具技术,在钢管内形成执徐结构     

平房仓屋面防水施工管理

平房仓屋面工程是仓房建设中的重要分部工程。仓房屋面防水施工是屋面施工中的重要工序,关系到仓房使用过程中的储粮安全。从事先、事中、事后各个环节提出平房仓屋面防水施工管理建议及注意事项,确保粮食安全储存。     

薄壳山核桃营养成分的研究进展

薄壳山核桃是一种新兴的营养健康食品。笔者通过回顾多年来国内外薄壳山核桃方面的研究文献,对薄壳山核桃中的重要营养成分及其健康功效进行综述。薄壳山核桃果实中主要含有油脂、酚类物质、维生素E和植物甾醇等。薄壳山核桃果仁具有保护心脑血管健康功能及抗氧化功能,薄壳山核桃壳具有抗氧化及抗焦虑功能。并通过与其他坚果的含油率、脂肪酸组成、酚类物质组成及含量、以及维生素E和植物甾醇含量进行比较,为中国未来薄壳山核桃果实品质的研究提供思路和建议,认为在重视优良品种的选育和应用的同时,重视研究薄壳山核桃对人体的健康功效也同样必不可少。     

G550高强冷弯薄壁槽钢受弯构件力学性能与设计方法

为了研究高强冷弯薄壁槽钢受弯构件的力学性能和设计方法,对3种板件加劲形式的G550高强冷弯薄壁型钢槽形截面受弯构件进行了试验研究和有限元参数分析。结果表明,板件加劲形式对高强冷弯薄壁槽钢受弯构件屈曲模式和受弯承载力有显著影响,翼缘V形加劲比腹板V形加劲能够更有效地提高构件抗弯承载力,构件抗弯承载力的变化规律与屈曲模式有关。根据有限元参数分析结果,在已有直接强度法基础上回归出适用于高强冷弯薄壁槽钢受弯构件的直接强度法修正公式。     

拱板平房仓屋面反光控温储粮试验

拱板平房仓屋顶面积大,拱板壳体薄,在阳光直射下,导热快,使仓温、粮温快速上升,不利于粮食安全度夏。通过对仓房屋面的改造,控制隔热层温度,延缓仓温和表层粮温上升,达到安全储粮的目的。     

薄壳山核桃的高产管理技术研究

以良种为基础、以精品工程为起点、以丰产优质为目标、以孤山国有林场薄壳山核桃基地为样板,通过实施薄壳山核桃良种丰产示范园和良种采穗圃建设,为全椒县周边薄壳山核桃产业发展起示范带动作用。全椒县地处江淮丘陵地区,属寒温带,适宜薄壳山核桃的生长发育。薄壳山核桃的树木管理应遵循春刻芽、夏摘心、秋拉枝、冬修剪原则。简析了薄壳山核桃的高产管理技术。     

新型太空隔热涂膜在高大平房仓的控温效果研究

低温储粮是一种科学、先进、绿色的储粮技术，具有保质、防霉、保鲜的作用。在仓房屋面涂刷一种新型太空隔热涂膜，利用其独特的绝热系统，反射太阳能量、降低热传导和物体结构上的热效力，有效地降低仓温，使粮温缓慢上升，进而延缓粮食品质劣变，达到比较理想的效果。     

高大平房仓屋面隔热与拱板通风降温改造

为了解决仓顶屋面隔热,拱板通风降温的问题,四川峨眉山国家粮食储备库存周正等人对高大平房仓进行改造试验.改造分两部分进行：     

聚氨酯发泡防水保温材料屋面施工技术

1998年由国家投资建设的我库高大平房仓，经过4年的使用，存在一个最大的问题：高温时节，气温很快影响仓温，仓温影响粮温上升，仓内最高温度达45℃。其原因为：使用的仓型为折线型屋架仓型，屋面水泥预制大板，现浇80mm厚珍珠岩隔热，上面做防水层。由于现浇珍珠岩受诸多施工因素影响，难以达到设计要求。2003年国家安排“提升功能”项目，对高大平房仓屋面采用硬质聚氨酯发泡防水保温处理。本文就此施工应用情况作一简单介绍。     

Research on the influence of structure integral performance to the RC frame structure failure mode(Ⅰ): Numerical analysis

Three models of 3D cast-in-place RC frame structures are simulated in ABAQUS. In the three models, one represents the actual RC frame structure with monolithic slab, one represents the open frame structure used in structural design currently, which means truss structure at the stage of calculating internal forces of frame beams and columns, and the third one represents the open frame structure which takes into account some slab reinforcement in the rectangle section of frame beam to consider the slab participation in the flexural capacity of frame beam. By investigating the failure mode of these three models, the development of plastic hinges, the reinforcement stress of beam, column and slab in the models, the influence of monolithic slab to the bending resistance of beam end is studied. It shows that the existence of slab makes the failure mode of actual RC frame structure different from the design criteria of strong column weak beam. It also indicates that the slab participation in the bending resistance of beam end is not only expressed in the slab reinforcement but also in the structure integral performance. Besides, when using the effective flange width to consider the slab reinforcement participation, the structure integral performance, lateral displacement and other relevant factors should be taken into account.     

Spatial Calculation Methods of Three Main Trusses Continuous Plate truss Composite Bridge

According to the structural features of three main trusses continuous plate truss composite bridge, two composite beam methods are presented by constructing the displacement mode of composite beam elements and deriving the stiffness matrix of composite beam elements. The characteristic of composite beam method one is that the bridge slab is taken as the top flange of the chord of main truss and combined with the chord of main truss to form a steel concrete composite beam; the characteristic of composite beam method two is that the bridge slab is taken as the top flange of longitudinal and traverse beam and form a steel concrete composite beam with longitudinal and traverse beams. And as for the conventional plate beam composite method, the slab is characterized by forming bridge slab system with continuous isotropic sheets and longitudinal and traverse beams to bear load. Also, the comparison between theoretical results and experimental ones verifies the effectiveness of the above three methods.     

Building Technology and Art of Tujia Folk Houses in the Southeast Chongqing

以"陕秋白"大白菜成熟叶球为试材,研究了低温条件下4种保鲜液的保鲜效果.结果表明,在保持切割白菜9分水平上,各处理的效果依次为D＞C＞ck＞B＞A;在7分水平上,各处理的效果依次为D＞A＞C＞ck>B;在5分水平上,A、C、D处理效果相近,高于对照,处理B与对照相近.总体比较,0.01%NaHSO3的D处理和0.01%NaClO的C处理保鲜效果较好.并对保鲜期间出现的褐变、霉变、愈伤组织等现象进行了分析与讨论.     

拱板仓屋面喷水储粮安全度夏效果研究

针对拱板仓储粮度夏粮温偏高、分层明显和温差较大的特点，利用自来水自动循环装置对仓顶屋面进行喷水降温，最大限度地减少了盛夏仓顶曝晒后的积热，缩小了仓顶与粮堆之间的温差，延缓了粮温的上升速度，从而有效地改善了储粮在盛夏的高温环境，抑制了害虫的生长繁殖和粮食品质的陈化，是拱板仓储粮安全度夏的有效方法。     

Experimental Analysis on the Longitudinal Shear Resistance of Flat-type Composite Slab

The shear bond behavior of the flat-type composite deck slab, Econdek65-675 is investigated primarily. Based on the Euro code 4, the relevant value, m-k, is achieved based on the test of 18 composite slab specimens. According to the thickness which is 115 mm, 150 mm and 200 mm respectively, these 18 specimens were divided into three groups with two sets in each group. One set was tested for shorter shear span loading and the other one was set for longer shear span loading. It is shown that the Euro code 4 is more accurate than the American code. Meanwhile, the calculation formula of longitudinal shear resistance of the composite slab as well as its relevant curve is presented. Compared with other similar composite slabs, it is proved that Econdek65-675 possesses reliable composite efficiency.     

高水分稻谷安全度夏控温及隔热储粮的综合应用

粮食收购市场化后,部分高水分的粮食进入粮库,严重影响储粮的安全.一年来我库对部分轮换入库高水分的稻谷首先采取边入库边通风降水,然后通风降温有效控制粮温;再采取薄膜密闭、稻壳覆盖隔离粮堆和屋面喷水隔热等多种隔热及控温储粮技术的综合应用,探索出一条高水分稻谷安全度夏的途径.     

THE THEORETICAL ANALYSIS OF RADIAL DISPLACEMENT AND COMPATIBLE CONDITIONS OF BOTTOM PLATE OF PISTON FRAME IN LARGE CONTAINER

Taking aecount of shear action between the piston truss the bottom plate, this paper assumes the bottom plate to be a part-ring and supposes that the shear distribution follows the power series law, making the problem to be a problem of mixed boundary condition of part plate. In the paper, the solution of this elastic plane problem is derived. The general expressions of radial displacement of bottom plate are given. The compatible conditions both at the nodes of the lower chord of the truss and at the central cylindrical shell are analyzed.     

Impact Mechanism of Member Initial Stress on Space Truss

To reveal distribution characteristics of member initial stresses, nine experimental prototypes in span of 4 m, 5 m and 6 m were employed. To analyze effects of member initial stresses on ultimate capacity of space truss, a prototype in span of 6m was applied. Meanwhile, the results were compared with those of Abaqus nonlinear FEM which were based on elastic-perfectly plastic model and Marshall Mode. Initial stress test shows that some initial stresses approach or even exceed stability stress. It is shown that the test ultimate capacity decreases by 17.9% than that of Marshall Mode, and the safety margin of structure is just 1.25. The impact mechanism of member initial stress consists in damaging structure initial symmetry, producing member initial bending and prompting press member buckling in advance. Member initial stress must be taken into account when space truss design, especially Fully-Stress design, is conducted.     

粮食安全储藏与房式仓保温隔热性能设计改进的探讨

从储粮生态系统控制的角度阐述了粮仓保温隔热性能的重要性和实用性,突出粮仓设计和使用的协调统一;针对新建粮食储备房式仓使用中多数出现仓顶隔热性差、门窗洞口气密性差、仓内粮面温度过高的问题,结合实践经验,对房式仓朝南墙面门窗的设计、保温隔热屋面的设计、仓内地坪适当下挖装粮的设计等进行了探讨,提出了实用性设计方法和"半地下储粮房式仓"新仓型的设计思路.     

Analysis of ultimate load and mechanismsof failure in large cast steel joints

Based on a project of pipe truss roof framing in Chengdu, the ultimate limit state analysis is performed on cast steel joints by using FEM, in which Linear hardening elastic-plastic constitutive model is considered. The results show that, the joint has a great accumulation of plastic strain in ultimate loads, and the point of maximum stress is different from that in elastic with the development of the yielding zone. The paper propoes to use rate-type tensor for the large strain geometric nonlinear problem, shows the criterion of failure formation , and indicates that its essential to apply limit state analysis to the determination of the weakest location on cast steel joint design, which provides basis for understanding the failure modes and failure mechanism of cast steel joint and the cast steel joint design.