钢箱梁桥面铺装层状体系承载力学响应

通过有限元分析方法,根据线弹性理论和层状体系理论,对钢箱梁桥面铺装层的弯拉应力、主剪切应力在层状结构间沿特征分析路径的分布及其沿层深的变化进行了计算与分析,确定了最大弯拉应力和最大层同剪切应力层位及其量值.研究结果可以为大跨径钢箱梁桥面柔性铺装设计提供理论参考.     

沥青路面层间粘结效果影响因素

为了保证沥青路面层间具有良好的粘结力,提高路面的整体性和耐久性,对沥青路面层间粘结效果的影响因素进行专门的试验研究.采用沥青路面层间扭转剪切试验仪,通过成型双层车辙板并钻芯,对芯样进行剪切试验,以最大剪切强度作为评价指标,对影响沥青路面层间粘结性能的沥青混合料类型、乳化沥青种类、乳化沥青洒布剂量、温度等影响因素进行了对比分析.结果表明.AC密级配沥青混合料层间粘结效果好于SMA和OGFC混合料;改性乳化沥青作为粘层比普通乳化沥青层间粘结效果要好,粘层洒布量有一最佳剂量,且这一最佳洒布剂量AC路面结构比骨架型路面结构要低;层间粘结效果随温度升高出现衰减,表明路面层间产生滑移,多发生在高温季节.     

饲用酶制剂对蛋鸡生产性能的影响研究

选用35周龄产蛋高峰期蛋鸡480只,随机分成2个处理,每个处理4个重复,每个重复60只鸡。以玉米—豆粕—杂粕型基础日粮为对照组,在此营养水平基础上添加0.05%的瑞特利禽专用饲用复合酶为试验组。结果表明:试验组产蛋率、蛋壳厚度分别比对照组提高1.65%和2.38%,并降低破蛋率0.248%,但差异不显著(p>0.05);饲料转化率提高2.41%,差异显著(p<0.05)。     

绝热层对钢包热行为的影响

建立了基于有限元法的钢包二维传热模型,运用Ansys软件对钢包在不同绝热层厚度情况下的热状态及保温性能分别进行了模拟计算.有绝热层的钢包可以明显地提高自身的保温性能,且随着绝热层厚度的增加,保温效果愈加突显,但幅度越来越小.与无绝热层的钢包相比,在绝热层厚度达到20 mm时,钢包预热时间缩短约1 h,节约煤气消耗1000 m3,降低钢水温降约6℃.在热饱和阶段,钢包外壁温度平均降低了100℃,包壁散热减小,1h可以节能1255680kJ,折合标准煤43kg.最后利用现场实测数据进行了验证,结果表明模拟结果正确可信.     

水泥基智能表层的研制及特性

研制了一种与混凝土结构相容性好的全域性应变传感器——水泥基智能表层,对这种新型传感器的静态特性进行了实验分析．对铺设有水泥基智能表层的实验梁进行三点弯曲实验,在不同挠度下,用数据采集系统和电阻应变仪分别测量梁上各等分段电压及其平均应变．实验结果表明,在弹性范围内,水泥基智能表层表现出良好的压敏性,电阻变化率与梁的平均应变有很好的一致性,反映了结构的应变规律．同时,当水泥基智能表层受压时,各段灵敏度大约为25～30．当水泥基智能表层受拉时,各段灵敏度大约为20-25,其灵敏度远大于电阻应变片的灵敏度2．且有良好的线性和重复性．     

Experimental Research on Methane Control of Mining Upper Protective Layers

In order to solve coal and gas outbursts during mining coal seam,studying on related problems were carried out. According to the theories of mining upper protective layer,proper mining plan were designed and performed through field experiment. By means of examining several parameters obtained from the field experiment,the protective effects were evaluated and the protective scope and related parameters were determined. The results of field experiment show that the danger of outbursts was evidently eliminated and the method of mining protective layers is effective and the safety and economic benefits are remarkable. The research has really applied worth and will give beneficial references to mining area with analogous conditions.     

基于三层交换的IP VPN系统设计

对现有的IP VPN的三种互连方案进行讨论，并指出了这三种方案的主要缺点是：硬件成本较高，集中讨论了有关虚拟路由器的概念、协议、功能及虚拟路由器的IP VPN构建方案，重点讨论了使用虚拟路由器连接和实现IPVPN的三种方案，第二层的虚拟路由器到虚拟路由器的连接方案、多个虚拟路由器聚合到一个虚拟路由器上的方案、多个骨干网的聚合虚拟路由器到聚合虚拟路由器连接方案。     

缓冲层对NiCo薄膜各向异性磁致电阻的影响

用磁控溅射法制备了以NiFeCr和Ta分别为缓冲层的两种NiCo薄膜样品,在不同温度下对两种样品退火.结果表明:在NiCo厚度相同的情况下,以NiFeCr作为缓冲层的样品的各向异性磁致电阻(AMR)值明显高于Ta作为缓冲层的样品.X射线衍射(XRD)的结果表明,NiFeCr/NiCo薄膜的晶粒平均尺寸大于Ta/NiCo薄膜,且两种样品的磁膜/缓冲层界面存在较大差异,这可能是造成两者AMR差异的原因.此外,对样品进行温度适当的热处理可以明显改善薄膜的物理性质.     

化学法在Ni-W基带上制备Ag缓冲层研究

在双轴织构的Ni-W基带上,采用化学镀银法为YBa2Cu3O7-δ(YBCO)涂层导体制备Ag缓冲层薄膜,并通过XRD和φ扫描研究烧结温度和镀银次数对Ag薄膜取向的影响。结果表明,在Ar-H2混合气氛下,于870℃镀银5次所制备的薄膜具有(200)晶面单一取向;采用化学法制备的Ag薄膜有较好的外延性,且适用于涂层导体中的单一导电型缓冲层。     

Formation of thermally stable alkylidene layers on a catalytically active surface

Materials containing organic-inorganic interfaces usually display a combination of molecular and solid-state properties, which are of interest for applications ranging from chemical sensing to microelectronics and catalysis. Thiols--organic compounds carrying a SH group--are widely used to anchor organic layers to gold surfaces, because gold is catalytically sufficiently active to replace relatively weak S-H bonds with Au-S bonds, yet too inert to attack C-C and C-H bonds in the organic layer. But although several methods of functionalizing the surfaces of semiconductors, oxides and metals are known, it remains difficult to attach a wide range of more complex organic species. Organic layers could, in principle, be formed on the surfaces of metals that are capable of inserting into strong bonds, but such surfaces catalyse the decomposition of organic layers at temperatures above 400 to 600 K, through progressive C-H and C-C bond breaking. Here we report that cycloketones adsorbed on molybdenum carbide, a material known to catalyse a variety of hydrocarbon conversion reactions, transform into surface-bound alkylidenes stable to above 900 K. We expect that this chemistry can be used to create a wide range of exceptionally stable organic layers on molybdenum carbide.     

微生态制剂对蛋鸡生产和免疫性能的影响

研究微生态制剂对蛋鸡的作用效果,为开发利用微生态制剂提供科学依据。将微生态制剂加入海兰白蛋鸡饲料中,通过记录鸡的采食量、产蛋量、蛋重、计算产蛋率、检测鸡血清中ND血凝抑制效价、统计肠道发病率、死亡率等探讨微生态制剂对蛋鸡生产性能和免疫功能的影响。结果表明:试验组的料蛋比比对照组降低了9.52%,差异极显著(P<0.01);产蛋率比对照组提高了5.35%,差异显著(P<0.05);平均蛋重提高了2.95%;350日龄及380日龄时试验组血清中新城疫血凝抑制抗体效价均高于对照组,分别高出对照组25.81%和25.42%;试验组的肠道病发病数、肠道发病率、死亡数和死淘率与对照组相比大大降低,肠道发病率和死淘率分别比对照组降低了66.67%和68.18%,差异显著(P<0.05)。     

Point defects in active layers of TFEL devices based on ZnS

Point defects in the active layer of a layered optimization thin film electroluminescent device of ZnS; Er³⁺ were studied. The results indicate that besides Er³⁺ substituting for Zn²⁺ as luminescent centers, the dominant point defects are sulfur vacancies, zinc vacancies, shallow donors and deep acceptors. Their influence on electroluminescence is discussed.     

4H-SiC同质外延拉曼散射光谱

在4H-SiC(0001)衬底上,使用CVD法生长不同掺杂浓度的外延层。将不同掺杂浓度的4H-SiC外延层,用拉曼散射光谱进行了研究。使用Matlab拟合了LOPC模的线型,并从理论上计算出载流子浓度,载流子浓度的理论计算值与SIMS测量的结果符合良好。随着掺杂浓度的变大,载流子浓度变大,LOPC峰发生蓝移,频移变大,散射强度变小,峰宽变宽。分析认为,LOPC峰发生蓝移主要和晶格振动有关,浓度越大,使得原子之间和晶胞之间的相互作用越强,致使出现蓝移现象。随着掺杂浓度的增大,声子增加,进而散射概率增加,散射概率降低了声子寿命,声子寿命和峰宽成反比,随着掺杂浓度增大,峰宽变宽。随着掺杂浓度的增大,散射强度越来越小。     

Ultrathin compound semiconductor on insulator layers for high-performance nanoscale transistors

Over the past several years, the inherent scaling limitations of silicon (Si) electron devices have fuelled the exploration of alternative semiconductors, with high carrier mobility, to further enhance device performance. In particular, compound semiconductors heterogeneously integrated on Si substrates have been actively studied: such devices combine the high mobility of III-V semiconductors and the well established, low-cost processing of Si technology. This integration, however, presents significant challenges. Conventionally, heteroepitaxial growth of complex multilayers on Si has been explored-but besides complexity, high defect densities and junction leakage currents present limitations in this approach. Motivated by this challenge, here we use an epitaxial transfer method for the integration of ultrathin layers of single-crystal InAs on Si/SiO(2) substrates. As a parallel with silicon-on-insulator (SOI) technology, we use 'XOI' to represent our compound semiconductor-on-insulator platform. Through experiments and simulation, the electrical properties of InAs XOI transistors are explored, elucidating the critical role of quantum confinement in the transport properties of ultrathin XOI layers. Importantly, a high-quality InAs/dielectric interface is obtained by the use of a novel thermally grown interfacial InAsO(x) layer (~1?nm thick). The fabricated field-effect transistors exhibit a peak transconductance of ~1.6?mS?μm(-1) at a drain-source voltage of 0.5?V, with an on/off current ratio of greater than 10,000.     

夹层对PCC-AC复合式路面层间剪应力的影响

针对PCC-AC复合式路面层间易产生脱离和滑移的问题,分析了夹层的设置对于PCC-AC复合式路面层间剪应力的影响,通过改变夹层的厚度和回弹模量来研究其变化规律,得出了夹层底剪应力的回归公式,提出了降低PCC-AC复合式路面层间剪应力的有效方法,即在不改变AC层厚度的情况下,设置适当厚度的低模量应力吸收层.     

基于结构层贡献率的沥青路面抗车辙措施

采用环道试验及德国汉堡车辙试验方法,研究在中面层使用改性沥青对路面结构和组合结构抗车辙性能的影响,包括对结构层贡献率和对沥青层剪切流动变形的影响;探讨在中面层添加纤维对路面结构抗车辙能力的影响.研究结果表明:中面层使用改性沥青,能提高路面结构的整体抗车辙性能;使剪切流动变形由95.2%下降至84.4%;中面层变形贡献率达到60%以上,应该重视提高中面层的抗车辙能力;对于中面层采用普通沥青的结构,在中面层添加纤维可明显减少整个结构车辙深度,但对于中面层已采用改性沥青的结构,添加纤维减少车辙的效果不明显.     

Fe-C-Cr-Mn堆焊层的抗冲蚀磨损性能

采用H08A焊芯碱性药皮改变药皮配方中高碳铬铁、钼铁及钒铁的加入量．可以获得不同成分的奥氏体基体 碳化物堆焊层。通过金相分析、硬度测定和冲蚀磨损试验．表明堆焊层主要为奥氏体或奥氏体 马氏体组织，堆焊层硬度较低．具有良好的抗大角度冲蚀磨损性能。当堆焊层中析出少量的碳化物时，可以提高抗小角度冲蚀磨损性能．但是．抗大角度冲蚀磨损性能稍有下降。