摘要：研究了流媒体代理缓存的特点和影响流媒体代理缓存效果的因素,分析了衡量流媒体代理性能的指标,设计了流媒体代理缓存管理文件的结构,最后给出了用户请求处理过程。

摘要：针对车辆悬架系统存在的参数不确定性,提出一种基于模型参考控制的车辆非线性主动悬架反推控制器设计方法。建立悬架系统非线性模型,引入高低通滤波器,根据悬架动行程改变高低通滤波器的通频带宽,设计一种理想的模型参考系统。在此基础上,构造被控悬架系统与模型参考系统之间的车身位移和速度跟踪误差,基于反推控制方法和Lypaunov理论设计了误差跟踪反推控制器。通过仿真实验验证了所提出的误差跟踪反推控制器的有效性和跟踪精度。

摘要：In the global background of“Carbon Peak”and“Carbon Neutral”,natural gas engines show great advantages in energy-saving and pollution ***,natural gas engines suffer from the issues of combustion instabilities when operating under lean burning *** this paper,the role of turbulence enhancement in improving the lean combustion of natural gas was investigated in an optical SI engine with high compression *** swirl control valves(SCV)were designed and intake tumble and swirl were combined to regulate turbulent motion and turbulent *** image velocimetry was employed to measure in-cylinder turbulence,and transient pressure acquisition and high-speed photography were synchronously performed to quantify combustion *** results show that incylinder turbulent intensity is enhanced significantly through reducing SCV closing *** that flame propagation speed and thermal efficiency are significantly improved with an increment of turbulent intensity,which indicated that mean effective pressures are not sensitive to spark *** analysis of flame images shows that the combined turbulence increases in the radial orientation from the spark plug to the cylinder wall,leading to an earlier flame kernel formation and a faster burning ***,the combined turbulence has the potential in reducing the cyclic variations of lean combustion in natural gas engines.

摘要：采用改进遗传算法对高层建筑的挤扩支盘群桩进行优化设计,将计算得到的群桩桩顶轴力根据大小进行分组,以各组基桩中所含承力盘数量作为遗传算法中的设计变量,建立了以群桩承力盘数量最少为目标函数,将群桩竖向承载力、最大沉降值、沉降差作为约束条件的挤扩支盘群桩优化模型。借助Python语言对ABAQUS进行二次开发,建立挤扩支盘群桩自动优化平台求解上述优化模型,获得最优群桩布置方法。结合算例表明,优化后的挤扩支盘群桩基础在承力盘数目减少的同时能降低差异沉降,使得筏板变形和桩顶受力更为均匀,有利于结构的安全和正常使用。

摘要：The rational design of polymer acceptors with strong and broad absorption is critical to improve photovoltaic *** this work,a new polymer acceptor PY9-T based on heptacyclic benzotriazole(Y9-C16)as a building block and thiophene unit as the linking unit was synthesized,which exhibited a low bandgap(1.37 eV)and a high extinction coefficient of the neat film(1.44×10^(5) cm^(−1)).When PY9-T was blended with the wide bandgap polymer donor PBDB-T,the all-polymer solar cells(APSCs)showed a high power conversion efficiency(PCE)of 10.45%with both high open circuit voltage of 0.881 V and short-circuit current density of 19.82 mA/cm^(2).In addition,APSCs based on PY9-T show good thermal stability,as evidenced by slight changes morphologies when annealed at 100℃.These results suggest that Y9-C16 provides a new building block to develop efficient and stable polymer acceptors.

摘要：该文以内蒙古达拉特发电厂3号锅炉为研究对象,针对其炉膛结渣问题,采用炉膛分区段热力计算方法,研究锅炉在设计煤种、高负荷运行时,投用不同层燃烧器和燃煤量,得出9种较为符合实际运行并可减轻结渣的燃烧工况;分析锅炉高负荷运行时改变煤种,投用一、三层燃烧器,每层依次投入总煤量的70%、30%时,各区段烟温和炉膛断面热负荷的分布情况。两种计算结果显示:达拉特发电厂燃用煤基本为严重结渣煤,容易引起炉膛、折焰角、过热器等处结渣。并采用了RTSQ综合判别法对达拉特发电厂16种煤进行了研究。结果表明:达拉特发电厂燃用煤与B&WB1025t/h锅炉炉型不匹配,引起炉膛多处结渣,最后提出了减轻结渣程度的设计与运行措施。

摘要：针对传统单片机设计的电梯控制器外围电路复杂,性能不稳的缺点,提出了基于FPGA的电梯控制器设计。控制器以FPGA芯片为核心,各种功能通过在FPGA设计工具中用VHDL语言进行描述,在集成软件环境中进行编译、调试及综合,使用专用下载电缆将程序代码下载到芯片中以实现其功能。从程序仿真图上可以看出该控制器提供6个楼层多用户的载客服务并指示电梯的运行情况。该方法不仅简化了电路设计,提高了控制器抗干扰性,而且降低了功耗,具有广阔的发展前景。

摘要：为了在变速器齿轮宏观参数设计阶段尽可能地降低齿轮啮合冲击振动,提出了一种斜齿轮宏观参数的减振优化设计方法。采用减小传递误差波动值作为减小冲击振动的手段,建立以减小冲击振动和体积为目标,同时考虑规范要求并保证强度的变速器斜齿轮宏观参数优化模型,采用遗传算法进行寻优。斜齿轮传递误差的计算方法考虑将斜齿轮副近似为众多小直齿轮副的叠加,并考虑相邻小直齿轮副的啮合角度的相位差,小直齿轮副的传递误差计算采用考虑轮体周向变形的改进石川法。优化结果表明,本文优化方法能够有效降低斜齿轮传递误差41%、降低体积1.34%。

摘要：设计了一种采用3个结构尺寸不同的压电振子进行电信号-音频信号转换的三分频式压电骨传导助听装置,该装置可以适应较宽的工作频率范围。对压电振子进行了模态仿真分析和谐响应仿真分析,得出了压电振子最佳振型和谐振频率,确定了各个压电振子的工作频率段。根据仿真结果设计制作了三分频压电骨传导助听装置试验样机,对样机的幅频特性和响度进行了试验测试。结果显示:助听装置中低频、中频和高频压电振子的最大振动幅值分别为86.08μm、34.24μm和1.545μm,且处于各自振动频率段内;低频、中频和高频压电振子在各自频段内响度最大,各频段的最大响度值依次为69.1dB、98.3dB和117.1dB。由于3个压电振子同时工作时,各频段声音都能得到较好的响应,因此拓宽了声音的响应频域。

摘要：The vicious cycle between tumor cell proliferation and bone resorption remarkably elevates the progression and metastasis of bone ***,we fabricated polyethylene glycol-conjugated alendronate-functionalized and chloroquine(CQ)-loaded polydopamine nanoparticles(PPA/CQ)for efficient treatment of bone tumors via breaking the vicious *** nanoparticles were efficiently accumulated to the bone tissues,especially the osteolytic lesions around *** released from PPA/CQ inhibited osteoclastogenesis via preventing the degradation of tumor necrosis factor(TNF)receptor-associated receptor 3 to attenuate the osteolysis in bone *** the other hand,CQ blocked the autophagy in cancer cells,resulting in improved photothermal killing of cancer ***,the in vivo experiment revealed that PPA/CQ-associated treatment efficiently inhibited both tumor growth and *** work suggests that autophagy inhibition-associated photothermal therapy could be a promising strategy for treating malignant bone tumors.