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The effect of water to cement ratio, fiber types and content, cement types on the bending performance of the extruded fiber reinforced cementitious board were studied. And it was found that polyvinyl alcohol (PVA) fibers can significantly improve the ductility of the board compared with polypropylene (PP) fibers. As PVA fiber content achieved 1.7%, the strain hardening and multiple cracking were occurred on the extruded board, while strain softening were shown on PP fiber reinforced cement board. The difference between the two kinds of board was from the differences of the mechanical properties of the two fibers. In addition, taking the fiber reinforced extruded board as base, the ultimate bending strength, as well as and the corresponded deflection and the resistant to chloride iron penetrating, was improved for a composite beam with fiber board and concrete compared with those of traditional concrete beam. 相似文献
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Yang Youkui Wu Gang Qiu Xiande Xiao Changfu 《保鲜与加工》1992,(2):1-6
Based on the discussion of the phenomenon that the effect of fracture toughness is neglected in general hydraulic fracturing models, this paper gives the energy balance equation in-colding all parameters in hydraulic fracturing and proposes a method of determining the apparent fracture toughness of rock from hydraulic fracture experimental data. The discussion on the factors affecting apparent toughness indicates the inevitability that the apparent fracture toughness of rock measured by hydraulic fracture experimental data is significantly higher than that measured by the standard three-point bending method. 相似文献
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Low cycle fatigue(LCF)properties of H-beam as hot-rolled and welded are studied, and the cyclic stress-strain relationship and cyclic response characterization are determined. Based on the Coffin-Manson formula, the strain-fatigue life relationship is obtained. Finally, the cyclic toughness, which is the product of strain range at LCF life of 100 cycles and the stress amplitude, are calculated. The test results show that the cyclic toughness as welded H-beam is 62% of that as hot-rolled. Hot-rolled materials exhibit cyclic stability, and welded materials show cyclic softening followed by fracture. The scanning electron microscope(SEM) micrograph of fracture surfaces reveals that the fatigue crack initiates from the coarse grain area of welding joint, and the fine dimple is observed in the fracture surface, which indicates the welding joint remains a good ductility. 相似文献
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为比较分析广东省主要鲜食橄榄果实质构特性的差异,探讨鲜食橄榄果实质地评价的量化参数,验证感官评价质地的有效性。采用质构刺穿试验法对7个优质鲜食橄榄品种果肉质构参数和2种水肥管理方式不同成熟期的‘香甜榄’果实品质进行测定和比较分析。结果表明,不同品种之间果肉的各质构参数变异系数为12.57%~23.95%,差异性显著,与感官评价一致;果皮强度与果皮脆性和果皮韧性均呈显著正相关,果皮破裂深度与果肉硬度呈显著负相关。采用本次试验栽培管理方式可以提高橄榄完熟果实可溶性固形物6%、可滴定酸3.5%、单宁54.9%、果皮强度12.7%、果皮脆性23.5%,降低粗纤维10%、果皮韧性13.7%。果实质地品质参数主成分分析表明,果皮强度、果实硬度和纤维指数可作为质地参数量化区分不同品种间的差别,并明确果皮强度、果实硬度分别小于2300、1600 g和纤维指数大于10,为鲜食橄榄果肉质地品质较好的数值范围。研究初步建立了利用质构刺穿试验法量化评价鲜食橄榄果实质地品质的方法。 相似文献
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Using WAW-2000 a multifunction servo-controlled testing machine,uniaxial quasi-static compression experiments for the steel fiber reinforced concrete(SFRC) were conducted with three strain rates.The volume fraction(V_f)of SFRC ranged from 0% to 3%,and the matrix was C50 concrete.The whole stress-strain curves of matrix and SFRC were obtained,and the results showed that with the increase of V_f,the compressive strength increased slowly,while the toughness increase quickly.With the increase of the strain rate,the strength of SFRC increased,but the toughness decreased,and the more the Vf,the less decreasing of the toughness.The results also showed that the elastic modulus and Poisson's ratio of SFRC were not sensitive material parameters,and with the increase of V_f,the former raised slightly and the latter decreased a little,respectively.A well suited numerical expression of the compressive stress-strain curve applicable to SFRC was put forward. 相似文献
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In this paper,four models are selected as the representatives and applied to nonlinear dynamic analysis program for space frames which is based on the beam-column elements using the finite element flexibility method and the fiber model.Park's test on combined axial and bending columns under cyclic loading are taken as the calibrations,comparisons to material and structural member level are drawn and the analytical results of various models are discussed. 相似文献
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为实现茶渣的综合利用,分析了不同种类速溶茶茶叶原料与茶渣中的主要成分及金属离子含量。理化指标含量分析结果表明,与原料茶叶相比,不同种类速溶茶茶叶茶渣中的粗蛋白、纤维素含量分别提高了25.77%~38.56%、32.57%~58.54%,而粗脂肪、灰分含量分别下降了61.55%~70.79%、47.72%~56.72%。品质指标含量分析结果表明,与原料茶叶相比,不同种类速溶茶茶叶茶渣中的茶多酚、咖啡碱、茶氨酸含量的下降率分别在58.34%~67.93%、46.95%~61.05%、49.33%~58.09%范围内。金属离子含量分析结果表明,与原料茶叶相比,不同种类茶叶茶渣中的金属离子铅、铜、砷、镉含量有所下降,但二者之间差异不显著。可见,速溶茶制作后的茶渣中依然含有较多的有益成分,特别是粗蛋白和纤维素,同时也含有较多的金属离子,研究结果为后续茶渣的综合开发与利用提供了前期研究基础。 相似文献
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以信阳杂交大米为原料,采用温水浸出抽提法分离纯化制取大米直链淀粉。以直链淀粉的提取率及含量为评价指标,通过对影响大米直链淀粉提取的淀粉乳浆质量分数、抽提温度及抽提时间等因素进行单因素试验和正交试验,优化其生产工艺技术。结果表明,最佳提取工艺条件为淀粉乳浆质量分数4%,抽提温度80℃,抽提时间25 min,在此条件下得到的大米直链淀粉的含量在97%以上,提取率17.47%。该方法提取直链淀粉纯度高、成本低,为进一步开展大米直链淀粉的研究提供了基础数据。 相似文献
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摘要：采用规格为3 m3/d的一体式中空纤维膜生物反应器（MBR）对某果汁厂石榴浓缩汁生产废水进行了净化处理应用研究。实验结果表明：当进水CODCr为756~1097 mg/L时,出水CODCr为34~95 mg/L,CODCr去除率为89.5%~97.0%。膜的截留作用占总去除率的10%~20%。该装置连续运行了60 d,出水均稳定达到排放标准。采用膜生物反应器工艺处理果汁废水技术可行、操作简单、易于管理,可节省50%左右的添加营养物质氮磷的成本,为工业规模应用提供了技术参考。 相似文献
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A novel biobarrier, whose reaction media consist of functional microbes, peat and coarse sand, is tested in laboratory to study the effect and the related mechanism in remediation of petroleum hydrocarbon contaminated groundwater. The results show that the removal efficiency for BTEX, naphthalene hydrocarbons and phenanthrene are 83.6%~99.85%, in which 71.23%~99.71% contaminants are removed at the first half part of biobarrier. The peat and functional microbes function steadily in contaminant sorption and biodegradation. 32.63%~77.98% BTEX and 97.14%~99.81% target PAHs are absorbed by peat and 18.96%~50.98% BTEX and almost all of the peat-absorbed petroleum hydrocarbon contaminants are degraded by microbes. Contaminant biodegradation can efficiently prolong the sorption life of peat barrier, and the efficient nutrients supply from peat to functional microbes can maintain the biomass at a relatively high level in the biobarrier, i.e. about 3.46×106~6.16×109 per gram dry media. Therefore, the novel biobarrier technology can be efficiently used in in-situ remediation of petroleum hydrocarbon contaminated groundwater. 相似文献
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陆地棉高品质品系纤维品质性状QTL的分子标记及定位 总被引：4，自引：1，他引：3
为进一步挖掘利用高品质品系NM03102的优异纤维品质性状的基因,利用陆地棉鲁棉研21作为母本、NM03102为父本构建了F2和F2∶3分离群体。通过7892对SSR引物对亲本进行筛选,获得222对多态性引物,进一步对195个F2群体单株分析得到242个标记位点。其中,182个标记位点连锁构建37个连锁群,共覆盖1661.6 cM,每个连锁群平均包含4.9个标记位点,标记间平均相距9.1 cM,其中35个连锁群被定位到了20条染色体上。利用F2和F2∶3纤维品质数据,通过复合区间作图法,共检测到20个纤维品质性状QTL。其中,1个纤维强度的QTL和1个纤维整齐度的QTL与已有的报道一致,1个纤维强度的QTL和1个麦克隆值的QTL在两世代中稳定存在,这为标记辅助选择奠定了基础。 相似文献
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张雁凌 《农产品加工．学刊》2011,(8):82-84
以大豆为原料,研究双螺杆挤压机各参数对大豆膳食纤维可溶性的影响,并以水溶性膳食纤维的含量为指标,通过单因素及正交试验筛选出最佳工艺条件:物料粒度50目,物料含水量16%,膨化温度140℃,螺杆转速450 r/min。该条件下水溶性膳食纤维质量分数为21.35%。 相似文献
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YANG Xi wu 《保鲜与加工》2008,(4):136-140
To prevent asphalt pavement from cracking under low temperatures and prolong its fatigue life, we tested the properties of a new type of steel fiber asphalt pavement. The tests evaluated Marshall stability, dynamic ruts, and cleavage strength under both low and normal temperature conditions. We also analyzed the anti-corrosion property of steel fiber and the factors affecting the properties of the steel fiber asphalt mixture. The steel fiber asphalt pavement was installed on a highway in Chongqing, P. R. China to investigate the construction art of the steel fiber asphalt mixture and examine its effect in field use. The test results and concrete use in the field show that the cleavage strength and flexibility of steel fiber asphalt concrete increase due to the action of steel fiber. We conclude that the anti-cracking capacity of asphalt pavement under low temperature conditions can be improved by steel fiber. The construction art of steel fiber asphalt pavement is the same as common asphalt pavement without the necessity of anti-corrosion processing for steel fiber. The research results are useful for pavement material selection in low temperature regions and heavy traffic road pavement designs. 相似文献
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根据GenBank公布的H9N2亚型禽流感病毒(AIV)M基因序列设计引物,通过反转录-聚合酶链式反应(RT-PCR)方法扩增H9N2亚型禽流感病毒M基因,并与GenBank中AIV M基因序列进行了同源性比较和氨基酸编码分析,绘制了M基因的系统发育进化树。结果表明：这6株病毒的M基因的核苷酸同源性在95.9-99.4%。M1蛋白的同源性在97.6-99.6%。M2蛋白的同源性在95.1-100%。进化分析这6株病毒都属于A/Quail/Hong- Kong/G1/97 (G1)-like 分支。这6株病毒的M2蛋白的第31位氨基酸存在S→N（AGT→AAT）的变异,都具有金刚烷胺的抗性。以106 EID50 的剂量,将H9N2 病毒鼻腔感染BALB/c 小鼠,结果表明H9N2 亚型流感病毒可以对哺乳动物小鼠可使得体重下降,也可致死。.本研究结果对于揭示H9N2 亚型禽流感流行规律和病毒的致病机理具有一定的意义。 相似文献