建筑机械高原作业适应性研究

分析了建筑机械在高原作业中存在发动机功率下降、启动困难,故障率增高,加速部件老化和磨损,影响建筑机械牵引性能和速度性能的变化和相同热平衡等问题,依据实际作业经验总结出了采用增压发动机和低温启动辅助措施,热平衡技术,冷却系统优化配置,选用耐低温材料解上述问题;同时通过改进驾驶室人机工程设计,提高驾驶员作业效率。     

Kinetics of Carnitine Palmitoyltransferase I (CPT I) in Chinese sucker (Myxocyprinus asiaticus) Change with its Development

The present study was conducted to evaluate the ontogeny and kinetic of CPT I in several tissues of the Chinese sucker Myxocyprinus asiaticus. To this end, liver, muscle and intestine tissues were examined at five various developmental stages of Chinese sucker: newly-hatched larvae, 68-day-old, 4-month-old, 1- and 2-year-old Chinese sucker, respectively. The total carnitine (TC) content in the liver increased from birth to 1-year-old Chinese sucker and then declined in the 2-year-old Chinese sucker. From the 68-day-old to the 1-year-old Chinese sucker, both free and total concentrations in muscle increased. Both acyl carnitine (AC) and TC concentrations in intestine were very variable at different stages. The ratio of AC to free carnitine (FC) in liver progressively increased from hatching to 4 months, and declined at the age of 1 year, and then increased by 2 years. In muscle, the highest and lowest ratios of AC/FC were observed at 68-days-old and 4 month-old Chinese sucker. The highest proportion of AC/FC in intestine was also observed at 68-day-old Chinese sucker. All the Chinese sucker larvae at hatching had a high value of the Michaelis constant (K _m) for carnitine. Maximal velocity (V _max) in intestine increased with age. V _max in liver and muscle increased with age except a decrease at 4 months in liver and at 2 years in muscle. The FC concentration in the examined tissues at all developmental stages were less than the respective K _m, indicating that Chinese suckers require supplemental carnitine in their food to ensure that CPT I activity is not constrained by carnitine availability.     

Spectrum-stable hyperbranched polyfluorene with photocrosslinkable group

Two kinds of blue light-emitting hyperbranched crosslinkable polyfluorene P1 and P2 with different contents of branch unit were synthesized via the palladium-catalyzed Suzuki coupling reaction, and the linear crosslinkable polyfluorene P0 was also prepared for comparison. The molecular weight and thermal behavior of the polymers were measured by GPC, DSC and TGA. Compared with uncrosslinked P0, P1 and P2, the photoluminescence spectra of crosslinked P0, P1 and P2 were little influenced. After annealing for 3 h at 200 °C in air, the photoluminescence spectrum of P2 with higher contents of branch unit showed more excellent stability compared with that of P1 and P0. The spectrum-stable hyperbranched polyfluorene can be used in multilayer and multicolor PLED.     

酸性橙Ⅱ半抗原及人工抗原的合成与鉴定

目的建立酸性橙Ⅱ半抗原及人工抗原的合成及鉴定方法。方法将重氮化后的2-氨基-5-磺基苯甲酸与2-萘酚经偶氮反应合成带羧基基团酸性橙Ⅱ,通过碳二亚胺法将其与载体蛋白(BSA)偶联制备酸性橙Ⅱ人工抗原。采用核磁共振碳谱和氢谱对合成的酸性橙Ⅱ半抗原进行结构分析,并用紫外光谱扫描法和蛋白质电泳法鉴定酸性橙Ⅱ人工抗原并计算偶联比。结果通过偶氮反应及碳二亚胺法最终得到纯化后的酸性橙Ⅱ半抗原约47 mg,核磁结果显示成功合成酸性橙Ⅱ半抗原。经SDS-PAGE、N-PAGE和紫外光谱扫描结果均显示酸性橙Ⅱ人工抗原蛋白分子质量大于BSA,所带负电荷大于BSA,且合成后的酸性橙Ⅱ人工抗原具有吸收峰叠加效应,均表明酸性橙Ⅱ人工抗原合成成功,偶联比为20.9:1。结论此方法能够成功合成酸性橙Ⅱ半抗原和人工抗原,为进一步制备特异性酸性橙Ⅱ抗体和建立酸性橙Ⅱ的免疫检测方法奠定基础。     

基于两步加权L1范数约束的高分辨率波达方向和功率估计

该文提出一种基于两步加权L1范数约束的波达方向(DOA)和功率联合估计新算法。该算法首先对阵列协方差矩阵元素进行求和平均运算获得统计性能更优的向量观测模型,进而在相应的过完备基下获得观测模型的稀疏表示。利用MUSIC谱函数和初始估计结果作为权值构建两步加权L1范数约束稀疏重构方法,重构获得多信源的DOA和功率估计。通过2分布函数选择了合理的正则化参数。计算机仿真结果显示,与同类其它方法相比,该文所提算法具有更高的分辨率和估计精度。     

Ce3+掺杂Li2O-MgO-Al2O3-SiO2玻璃的结构与荧光猝灭现象

采用熔融淬冷法制备了不同浓度Ce³⁺离子掺杂的20Li₂O-5MgO-20Al₂O₃-55SiO₂玻璃闪烁材料。采用X射线衍射(XRD)、高分辨透射电镜(HRTEM)技术、密度检测等方法研究了玻璃的微观结构随Ce³⁺离子掺杂浓度的变化规律, 采用荧光分光技术检测了玻璃的紫外光致激发光谱(PLE)、发射光谱(PE)。研究结果表明: 在不对称的晶体场作用下, Ce³⁺离子5d能级被劈裂为5个组分; 随着玻璃基质内Ce³⁺离子掺杂浓度增大, 玻璃的非晶化程度加深; 5d能级的劈裂宽度随之增大, 由此导致激发带向低能量端展宽、发射光谱明显红移; Ce³⁺离子的荧光发射强度随Ce³⁺离子掺杂浓度先升高、后降低, 浓度猝灭过程成为其荧光发射效率降低的主要原因。     

基于位置预查询的因特网移动支持方案

提出一种预查询移动支持方案(mobile Internet protocol_based on location pre-query,简称MIP_Q),以解决家乡网络的流量瓶颈和单点故障问题,从而提高移动通信的效率和可靠性.MIP_Q通过扩展域名服务系统管理和跟踪移动节点的当前位置信息,省去了家乡代理;采用并行切换控制方式,同时避免了MIP(mobile Internet protocol,简称MIP)中的三角路由和隧道路由问题;借助有效的计算方法,分析和比较了MIP_Q与MIP,MIP_LR的平均移动通信成本和切换时延;在实现方面与广泛应用的广域蜂窝移动网络进行了类比.结果表明:MIP_Q在切换效率和新增实体数等方面优于同类方案;MIP_Q可以极大地降低节点的移动通信成本,减小切换时延;MIP_Q具有良好的可行性.最后提出MIP_Q的仿真和实现方案.     

挖掘最大频繁模式的新方法

由于其内在的计算复杂性，挖掘密集型数据集的频繁模式完全集非常困难，解决方案之一是挖掘最大频繁模式集．该文在频繁模式完全集挖掘算法Opportune Project基础上，提出了挖掘最大频繁模式的新算法MOP．它采用宽度与深度优先相结合的混合搜索策略，能恰当地选择不同的支持集表示和投影方法，将闭合性剪裁和一般性剪裁相结合，并适时前窥，实现搜索与剪裁效率最优化．实验表明，MOP效率是MaxMiner的2～8倍，比MAFIA高2个数量级以上．