多路V/I输出的高性能CMOS带隙基准源

在传统CMOS带隙基准源的基础上,采用温度补偿和差分负反馈的方法,提出了一种多路V/I输出的高性能CMOS带隙基准源结构.基于0.5 μm CMOS工艺,进行了设计实现.HSPICE仿真结果表明,该带隙基准源具有较低的温度系数(7.9×10-6/℃,0～100 ℃),电源电压从1.9 V变化到5.5 V,输出仅变化1.8 mV,基准源输出为1.233 V,分压电路产生多路输出,基准电流4 μA,温度系数均小于12×10-6 /℃(-25 ℃～125 ℃).     

激光脉冲输出能量与脉冲宽度相互关系特性实验研究

本文分析了激光脉冲输出能量与激光脉宽的相互关系特性,实验证明在激光重复频率为10Hz和不改变激光器硬件参数的情况下,通过控制激光脉冲输出能量的大小来调节激光脉宽的方法是可行的;另外应用这种方法还可以预防和减小激光对光学器件的损伤.     

潮气量设置对部分二氧化碳重复吸入心输出量测定准确性影响的动物实验研究

目的:探讨机械通气潮气量设置对部分CO2重复吸人心输出量测定准确性的影响,为临床应用提供依据.方法:选用重庆地区健康雄性杂种犬8只,麻醉后气管切开机械通气.接无创心输出量监测仪(美国NICO),应用部分C02重复吸入法测定心输出量(CORB);同时经右颈内静脉插人肺动脉漂浮导管,以热稀释法测定有创心输}}{量(COrD).改变机械通气参数潮气量没置,分别在潮气量12ml/kg、6ml/kg条件下用两种方法同时测定心输出量,两种方法所测心输出量进行自体配时相关性研究.结果:配对t检验尔潮气量为12ml/kg时,CORB为5.40 L/min±1.35 L/min,COro为5.31 L/min±1.42 L/min,CORB和COTD比较,差异无显著性(P>0.05);cow和COrD的偏差、精确性分别为0.19和1.06,相关系数为0.90,容许范围为-1.78 L/min至+2.14L/min;Vt设置为6ml/kg时CORB为4.21 L/min±1.20L/min,COTD为5.65 L/min 4-1.61 L/min,CORB较COTD低,差异有显著性(P<0.05),两者的偏差、精确性分别为-1.68和1.04,相关系数为0.74,容许范围为-3.78 L/min至+1.58L/min.结论:部分'二氧化碳重复吸人无创心输出量与热稀释有创心输出量相关性良好,潮气量是影响CORB准确性的因素之一.     

Achievable sum‐rate analysis of correlated two‐antenna MIMO uplink channels

This paper analyzes the achievable sum‐rate of correlated two‐antenna multiple‐input multiple‐output (MIMO) uplink channels. Most of previous works have considered the case when a single user has multiple transmit antennas (i.e. multi‐antenna single‐user scenario). This paper considers the case when two‐antenna MIMO uplink channels comprise two users with a single transmit antenna (i.e. single‐antenna two‐user scenario). The analytic and simulation results show that the achievable sum‐rate of correlated single‐antenna two‐user MIMO uplink channels highly depends on the angle difference between the receive correlation coefficients of two users. It is also shown that the achievable sum‐rate of correlated single‐antenna two‐user MIMO uplink channels is larger than that of correlated two‐antenna single‐user MIMO uplink channels and can even be larger than that of independent and identically distributed Rayleigh two‐antenna MIMO uplink channels. Copyright © 2009 John Wiley & Sons, Ltd.     

QoS‐Guaranteed Multiuser Scheduling in MIMO Broadcast Channels

This paper proposes a new multiuser scheduling algorithm that can simultaneously support a variety of different quality‐of‐service (QoS) user groups while satisfying fairness among users in the same QoS group in MIMO broadcast channels. Toward this goal, the proposed algorithm consists of two parts: a QoS‐aware fair (QF) scheduling within a QoS group and an antenna trade‐off scheme between different QoS groups. The proposed QF scheduling algorithm finds a user set from a certain QoS group which can satisfy the fairness among users in terms of throughput or delay. The antenna trade‐off scheme can minimize the QoS violations of a higher priority user group by trading off the number of transmit antennas allocated to different QoS groups. Numerical results demonstrate that the proposed QF scheduling method satisfies different types of fairness among users and can adjust the degree of fairness among them. The antenna trade‐off scheme combined with QF scheduling can improve the probability of QoS‐guaranteed transmission when supporting different QoS groups.     

极点与H_∞指标约束下的满意容错控制

研究了线性不确定系统区域极点与H∞指标约束下的动态输出反馈容错控制器的设计问题.基于连续型执行器故障模式,利用有界实引理和线性矩阵不等式,给出了区域极点指标与H∞指标约束相容性理论及条件,并且分析了区域极点指标相容的H∞指标的取值范围.最后给出了同时满足区域极点与H∞指标约束下的动态输出反馈控制器的设计方法和步骤.仿真示例验证了提出方法的有效性.     

如何提高新型粘胶短纤纺丝机产量

随着国内外粘胶纤维需求量不断增大,我国粘胶纤维的产量也在快速增加,传统的粘胶短纤纺丝机无论在产量、规模、纺丝品种及纺丝工艺方面均不能满足市场的需求,这对纺丝机提出了更高的要求。就如何提高新型粘胶短纤纺丝机的产量进行了探讨。     

隔膜法制碱减产方式的选择

讨论了隔膜法电解制碱削减产能时常采用的2种减产方式的优劣,并通过对设立的减产条件下按照2种减产方式削减产能后的成本进行计算和比较。     

计及出力水平影响与自相关性的风电预测误差模拟方法

风电的预测误差不仅受预测出力水平的影响,而且时序上也存在显著的自相关性,基于此,提出一种兼顾两方面特征的风电预测误差模拟方法。充分利用Copula函数在描述变量间相关性方面的优势,通过分析风电出力的预测值与实际值间的联合概率分布,确定不同预测出力水平下预测误差的条件分布函数,对相邻时刻预测误差的相关性进行建模,并结合预测误差的条件分布函数,生成具有特定相关关系的备选数据列。顺次以前一时刻的预测误差为依据,从备选数据列中选取相应数据组成预测误差的模拟序列。算例仿真验证了所提方法的有效性。