Limitations of nonlinear discrete periodic control for disturbance attenuation and robust stabilization

This paper presents a performance analysis of nonlinear periodically time-varying discrete controllers acting upon a linear time-invariant discrete plant. Time-invariant controllers are distinguished from strictly periodically time-varying controllers. For a given nonlinear periodic controller, a time-invariant controller is constructed. Necessary and sufficient conditions are given under which the time-invariant controller gives strictly better control performance than the time-invariant controller from which it was obtained, for the attenuation of l_p exogenous disturbances and the robust stabilization of l_p unstructured perturbations, for all p[1,∞].     

用于速调管的一维光子晶体圆柱腔分析

运用ISFEL3D软件对一维光子晶体圆柱腔和金属圆柱腔进行仿真和分析。研究结果表明,一维光子晶体圆柱腔中与TM010模相邻的TM910模只存在于最外层介质中,频率间隔为213 MHz,不会影响TM010模;一维光子晶体圆柱腔的特性阻抗(94.9Ω)比金属圆柱腔(129Ω)要小,但均匀性要好;在一维光子晶体圆柱腔两端连接漂移管后,TM010模所受影响很小,说明一维光子晶体圆柱腔具有较强的抗干扰能力,这是将一维光子晶体圆柱腔应用在高射频段速调管方面的前提条件。     

钨锰矿(010)表面电子结构及性质第一性原理计算

用基于密度泛函理论的DMol3计算了钨锰矿不同(010)断裂键解理面的结构弛豫、Mulliken电荷布居和表面能,考察不同断裂键方式对表面能及表面电子结构性能的影响。锰钨矿单晶胞中Mn—O键比W—O键离子性强,平均键长更长,键能更小,沿Mn—O键断裂所形成的(010)解理面具有更小表面能,性质更稳定,是钨锰矿的理想(010)解理面。理想钨锰矿(010)解理面电荷密度差和态密度分析结果表明,Mn原子是表面活性原子,由于表面相中Mn—O原子相互作用较体相中增强,表面Mn原子活性降低。第一性原理计算结果能为实际矿石浮选的深入理论研究提供指导和参考。     

基于无线通信的机载振动压路机压实度检测系统

为了精确检测压实度,以提高振动压路机压路质量和效率,建立了振动轮-土壤系统的数学模型,采用加速度传感器作振动特性检测元件,用新型的CygnalF010单片机作智能处理部件,研制出基于USB接口的机载振动压路机压实度检测仪.该仪器小型轻便,操作界面友好、简捷,既能现场显示和打印测量结果等数据,又能通过USB接口与上位机通信.该仪器通频带宽范围为0.30～50 Hz,测量误差≤3%,线性度0.5%,特别适用公路建设和公路检测部门使用,也可以推广到铁路、土建等部门使用.     

Biodiesel from jatropha: Can India meet the 20% blending target?

The need for biofuels, particularly liquid ones like ethanol and biodiesel, has been felt by most of the countries and their governments have been trying to promote these fuels. Following in line with global trend, India declared its biofuel policy in which biodiesel, primarily from jatropha, would meet 20% of the diesel demand beginning with 2011–2012. In spite of the efforts made by the state, production of biodiesel, however, has not picked up at all. Doubt arises as to whether the country will be able to meet the target. It is felt that the government policy, particularly regarding land utilization, organizing cultivation of jatropha and pricing of jatropha seeds, needs to be more clear. This paper attempts to make an assessment of the state of India’s biofuel programme and to identify the hurdles that policy-maker need to overcome to achieve the goal.     

奥瑞克010临床前安全性评价

目的 奥瑞克010(OrienX010)以人单纯疱疹病毒(HSV-1)为载体,携带人源性或鼠源性的GM-CSF基因.在符合GLP的条件下,应用BALB/c小鼠和豚鼠进行临床前安全性评价研究.方法 小鼠急性毒性试验中,采用最大耐受剂量法对BALB/c小鼠尾静脉和肌内注射人源OrienX010和鼠源OrienX010M;全身过敏实验中,豚鼠隔日3次肌内注射OrienX010或牛血清白蛋白V,于末次给药后第10日静脉注射OrienX010,观察3 h内动物的变化;体外溶血试验中,观察本品在3 h内有无溶血和聚集现象.结果 BALB/c小鼠尾静脉注射人源OrienX010和鼠源OrienX010M的最大耐受量分别为4×107pfu和2×107pfu,肌内注射人源OrienX010和鼠源OrienX010M的最大耐受量均为6×107pfu,对豚鼠未见过敏反应,家兔无溶血现象.结论 动物实验结果表明,奥瑞克010制剂安全可靠,毒性较低,且无溶血和过敏反应.     

1兆位5伏闪速电擦除存储器AT29C010A及其应用

AT29C010A是ATMEL公司推出的5V闪速电擦除存储器（EPROM）,它采用ATMEL公司先进的永久性CMOS技术制造,可快速准确地实现单片机系统编程开发的需要,因此,它可广泛应用于各种单片机系统。文中介绍了它的特点、结构和基本工作原理,并给出了AT29C010A在微型心电图机中的实际应用。     

Sand–concrete interface response: The role of surface texture and confinement conditions

Sand–concrete interface direct shear tests were used to investigate the effects of surface roughness, surface waviness, mean sand diameter and relative density on interface strength and behavior under different confinement conditions. Extreme concrete surface textures, including smooth, rough and rough–wavy textures, were reproduced. Surface plowing was assessed via image analysis, laser scanning and extended multifocal micrographs. The experimental results showed that smooth concrete surfaces exhibited high values of interfacial–to–internal friction angle ratios, ranging 88–90%, due to the angular shape of sand particles. The rough concrete surfaces generated higher interface strength than smooth concrete surfaces; however, the interface strength was still inferior to the surrounding sand strength. Surface plowing, which identified a mixed shear plane at the sand–concrete interface, was developed as particles were detached from the surface, thus inhibiting the interface friction angle from reaching the sand friction angle. Higher sand–concrete interface strength was achieved as surface waviness increased, and interface friction angles greater than the surrounding sand friction angle were reached. Under a constant normal stiffness condition, significantly high interface strength is achieved due to the increase of the current normal stress, which was directly influenced by the initial normal stress, stiffness, surface roughness, mean sand diameter and relative density; surface waviness did not have a marked effect on the normal stress variation. Based on these results, multiple regressions were proposed to estimate the sand–concrete interface strength by the interfacial–to–internal friction angle ratio and the effect of the constant normal stiffness condition.     

Laser CVD Growth of Uniquely <010>-oriented β-Ga2O3 Films on Quartz Substrate with Ultrafast Photoelectric Response

The oriented growth of β-Ga₂O₃ films has triggered extensive interest due to the remarkable and complex anisotropy found in the β-Ga₂O₃ bulks. Remarkable properties, including stronger solar-blind ultraviolet (SBUV) absorption, better mobility, and higher thermal conductivity, are usually observed along <010> direction as compared to other low-index axes. So far, <010>-oriented β-Ga₂O₃ film growth has been hindered by the lack of suitable substrates and higher surface energy of the (010) crystal plane. Herein, the first growth of uniquely <010>-oriented β-Ga₂O₃ films on quartz substrates by laser chemical vapor deposition (LCVD) are reported. By investigating the effects of deposition temperature (T_dep) and O₂ flow rate (R_O2) on the growth of β-Ga₂O₃ films, it is found that the formation of <010> orientation is closely related to the higher stability of oxygen close-packed planes under O-rich condition. As a result, a grain size of up to ≈2 µm and a deposition rate of up to ≈ 40 µm h⁻¹ are obtained. Metal-semiconductor-metal (MSM) type detector based on <010>-oriented β-Ga₂O₃ film exhibits ultra-fast response speed, 1–2 orders of magnitude higher than those of most detectors based on β-Ga₂O₃ films with other orientations.     

Flower-like hierarchical Li1.2Ni0.13Co0.13Mn0.54O2 by architectural design for lithium-ion batteries with superior capacity retention

In this work, hierarchical flower-like Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ (LNCM) with exposed {010} planes assembled and double-sphere Li_1.2Ni_0.13Co_0.13Mn_0.54O₂ without {010} planes as a comparison were successfully synthesized via a simple solvothermal method. The diffusion of Li⁺ could be enhanced in the flower-like LNCM with exposed {010} active planes, and the cathode exhibits a superior electrochemical performance especially in long-term cycling stability even at high current densities. The initial discharge capacity of this sample is 274 mA h g⁻¹ at 0.1C (25 mA g⁻¹), with corresponding initial coulombic efficiencies of 77%. Especially, the capacity retention reaches up to 98% at 1250 mA g⁻¹ current density after 100 cycles. By comparing with other LNCM materials reported recently, our optimal cathode has a pretty outstanding electrochemical performance, which is promising for the next generation lithium ion batteries.