网络拓扑初步(下)

(二)切组矩阵,以节偶为基础的网络分析 1.切组矩阵:在讨论网络变量时,曾指出可以选取一组n个树枝电压作为独立的电压变量. 以图1的网络及图3的树为例,树枝电压v_2、v_4、v_6、v_8、v_9可以作为一组独立的电压变量,设它们对应于节偶电压:     

激光荧光色散谱研究气相二氯卡宾分子

本文报道了在交叉分子束装置中氟原子和二氯甲烷以及氧原子和二氯乙烯分子反应生成CCl_2的激光诱导荧光光谱的实验结果。位于520-610nm范围内的激光诱导荧光色散谱由9个峰组成,被归属为CCl_2的A(4,0,0)→X(0,v_2″,0),(1,v_2″,0)的跃迁。从光谱导出基电子态的弯曲振动频率v_2″=337cm~(-1),对称拉伸频率v_1″=737cm~(-1),X_(12)″=-1.26cm~(-1),X_(22)″=2.86cm~(-1)。文章还分析了两个反应的反应通道。     

CH_2Cl_2分子慢振动-振动能量转移——SSH理论计算

本文对CH_2Cl_2与惰性气体混合物碰撞弛豫过程,用SSH理论计算了CH_2Cl_2分子的v_8/v_9振动模到平动自由度能量转移的相对跃迁几率。计算结果与激光诱导荧光法的实验数据比较证实:CH_2Cl_2分子的最低振动模v_4与其它上振动模之间存在着慢的V-V能量转移。     

二极管激光微分光谱技术和CH_3CN分子ν_4带的研究

报道了CH_3CN分子v_4带二极管激光微分光谱,观察到v_4带约120条谱线。利用改进的最小二乘方拟合方法得到了新的分子常数。     

耿氏二极管阻抗新的测量方法

为了很好地设计振荡器、放大器及其它在脉冲通讯中需要快速开关的电路,必须知道半导体有源器件的微波阻抗,特别需要确定器件负电导g_d随射频电压幅度v_(ac)的变化。迄今这些参数是由测量有源振荡器件作为负载的微波网络的阻抗得到的,并取所测出的负值作为器件的阻抗。这种方法假定g_d(v_(ac))的斜率是负的,v_(ac)的极限范围可以控制。遗憾的是这种实验方法缓慢而烦琐。     

CO_2-N_2-H_2O激光体系的振动弛豫过程

讨论了驰豫过程中的一些重要问题:CO_2(v_3)的分子内V-V传能机制;水对驰豫过程的重要效应的机制;CO_2的v_1与v_2间的共振传能;膨胀流与压缩流的弛豫速率的同异;不同转动能级间和同一振型的不同振动能级间存在不平衡的可能性.指出了需进一步研究的问题.此讨论的内容亦适用于其它气体激光体系.     

频率和相位闪烁效应及频率源中的白频率和白相位起伏

引言信号发生器的频率稳定度可用Y(t)的单边带频谱密度表征。Y(t)是信号发生器标称频率信号输出电压V(t)的相对频率偏移。因此假定 V(t)=[V_0 ε(t)]Sin[2πv_0 φ(t)] (1) Y(t)=φ(t)/2πv_0 (2) S_y(f)=(1/2πv_0)~2S_φ(f) (3) S_y(f)=(1/v_0)~2f~2S_φ(f) (4)虽然S_y(f)是频率源的频率稳定度的基本定义,也是频率和时间技术委员会频率稳定度IEEE分会所推荐的定义,而采用射     

CH_3F与~(12)CO_2和~(13)CO_2分子之间的振动能量转移

我们采用Q开关的CO_2激光9.6μmP(20)支泵浦CH_3F分子的v_3振动模,以此作为能源来激发~(12)CO_2和~(13)CO_2分子的弯曲振动模v_2,研究其在非弹性碰撞过程中分子能量转移过程。我们用一种比红外荧光法(LIF)分辩率高一万倍的新方法——二极管激光探测法来得到~(12)CO_2、~(13)CO_2能级粒子数的演变过程。实验测得在1CO_2:1CH_3F气体比例下,从CH_3F的v_8振动模至CO_2的v_2振动模的V-V转移速率为3.3ms~(-1)Tcrr~(-1)。     

研究信息

小型光栅调谐 CO_2激光器的研制和 CO_2分子一些转动常数及谱带中心的测定(上海师范大学郭增欣等)本文介绍了使用自制光栅可调 CO_2激光器对CO_2分子的 v_3～v_1(00~01～10`00)和 v_3～2v_2(00~01～02~00)谱带的发射光谱精细结构进行分析,对上述两个谱带分别测定了43条和47条谱线的波数,进而利用并合关系计算了00~01、10~00和02~00三个振动态的转动常数 B_(00~01)、B_(10~00)、B_(02~00)以及上述两谱带的中心。文中将所得结果与先前从吸收光谱中所取得的公认值作了比较,在准确度方面基本一致。     

SiH_4v_1带CARS谱的分析及计算模拟

本文测量了室温下硅甲烷(SiH_4)低分辨率和较高分辨率CARS光谱。低分辨率SiH_4的CARS谱与M.Hanabusa、H.Kikuchi等人的结果相同,但我们对光谱提出了新的分析;高分辨率SiH_4的CARS谱及其理论计算证实了我们所作的分析;并得出了SiH_4v_1带和v_3带Q     

How visual feedback of decomposed movements of the center of pressure trajectories affects undisturbed postural control of healthy individuals

The center-of-pressure (CP) trajectory is a complex movement comprising both the vertically projected displacements of the centre-of-gravity (CG(v)) and the CP - CG(v) differences whose magnitudes are proportional to the horizontal accelerations communicated to the CG. One may, therefore, investigate whether the information given by these movements can be differentially used for controlling the standing posture. To this aim, a group of healthy adults was tested through four conditions including visual feedback (VFB) of their CP in real time and, with a 578 ms delay, CP, CG(v) and CP - CG(v) movements. The CG(v) and, thus, CP - C G, movements, were implemented from a numerical filter applied to the CP displacements. The postural behavior was assessed on the basis of basic CG(v) and CP - CG(v) movements estimated from the CP trajectories. The postural behavior observed during delayed CG(v) feedback was similar to the one observed with the similarly delayed CP movements feedback. On the other hand, the delayed CP - CG(v) feedback infers a decrease of the CP - CG(v) movements and concomitantly an increase of the CG(v) movements. This data highlight that there is enough information in the displayed CP trajectories to enable control of the CG and that providing CP - CG(v) information can lead the subjects to solely decrease these movements.     

Comparison of the pharmacological properties of rat Na(V)1.8 with rat Na(V)1.2a and human Na(V)1.5 voltage-gated sodium channel subtypes using a membrane potential sensitive dye and FLIPR

A novel, membrane potential sensitive dye and a fluorescence imaging plate reader (FLIPR) have been used to characterize the pharmacological properties of rat Na(v)1.8 voltage-gated sodium channels (VGSC) in parallel with rat Na(v)1.2a and human Na(v)1.5 VGSC subtypes, respectively. The sensitivity of recombinant Na(v)1.2a-CHO, Na(v)1.5-293-EBNA, and Na(v)1.8-F-11 cells to VGSC activators was subtype dependent. Veratridine evoked depolarization of Na(v)1.2a-CHO and Na(v)1.5-293-EBNA cells with pEC(50) values of 4.78 +/- 0.13 and 4.84 +/- 0.12, respectively (n = 3), but had negligible effect on Na(v)1.8-F-11 cells (pEC(50) < 4.5). Type I pyrethroids were without significant effect at all subtypes. In contrast, the type II pyrethroids deltamethrin and fenvalerate evoked direct depolarization of Na(v)1.8-F-11 and Na(v)1.5-293-EBNA cells. Deltamethrin potentiated the veratridine-evoked response in Na(v)1.8-F-11 cells by > or =20-fold, in contrast to a 相似文献   

Experimental nonsaturating velocity-field characteristic of GaAs

The equal areas rule method is used to determine the velocity-field characteristic (v = v(E)) from the experimental data measured on a GaAs sample when a high-field domain is in transit. The v = v(E) characteristic is close to that measured by Ruch and Kino for the electric fields below about 15 kV/cm and does not saturate for higher electric fields, which is in agreement with Heinle's theoretical analysis.     

双多晶硅栅SOI MOS器件的研究

采用多晶硅栅全耗尽ＣＭＯＳ／ＳＩＭＯＸ工艺成功研制出多晶硅栅器件,其中Ｎ＋栅ＮＭＯＳ管的阈值电压为０．４５Ｖ,Ｐ＋栅ＰＭＯＳ管的阈值电压为－０．２２Ｖ,在１Ｖ和５Ｖ电源电压下多晶硅栅环振电路的单级门延迟时间分别为１．７ｎｓ和３５０ｐｓ,双多晶硅栅ＳＯＩ技术将是低压集成电路的一种较好选择。     

光学厚度预报因子对风云四号卫星扫描辐射计红外通道快速正演精度的影响分析

快速辐射传输模式利用光学厚度预报因子与卫星通道光谱特征系数可实现通道透过率的快速计算,并达到与逐线积分模式相当的正演精度.针对FY-4 AGRI的6个红外通道,分别建立了基于RTTOVv7、v8、v9和CRTMv2.1(以下简称四种模式)光学厚度预报因子的快速正演算子,与逐线积分模式的结果对比,分析了四种快速正演算子中均匀混合气体、水汽线吸收和水汽连续吸收预报因子对正演误差的影响.分析表明,四种快速正演模式计算通道亮温与逐线模式结果相比,在温度探测通道的最大标准差要小于0.6K.v9模式在水汽和温度通道的正演误差远小于其他三个模式;四个模式在窗区通道的误差基本相当.v9模式预报因子中,引入实时大气与参考大气的整层离差减小了均匀混合气体光学厚度的正演误差.     

1588v2在电信网应用的标准化进程

文章介绍了1588v2在电信网领域应用的背景、需求和主要标准组织ITU-T的相关工作进展,包括频率同步应用和时间同步应用。通过分析目前1588v2电信应用规范中的热点问题,如影响1588v2频率恢复性能的网络分组延时变化(PDV)指标、1588v2端到端频率传送的应用场景和协议规范,提出1588v2在电信网络部署的可靠性、可管理维护等特点和基本思路,并对未来标准化需要解决的问题进行总结。     

Constructions for Perfect 5-Deletion-Correcting Codes of Length$7$

There are two kinds of perfect (k-t)-deletion-correcting codes with words of length k over an alphabet of size v, those where the coordinates may be equal and those where all coordinates must be different. We call these two kinds of codes T*(t,k,v)-codes and T(t,k,v)-codes respectively. Both a T*(t,k,v)-code and a T(t,k,v)-code are capable of correcting any combination of up to (k-t) deletions and insertions of letters occurred in transmission of codewords. In this correspondence, we consider constructions for the codes from directed designs. By means of these constructions, the existence of a T(2,7,v)-code is settled for all positive integers v with the exception of 68 values of v; T^*(2,7,v)-codes are constructed for all integers vges2350. A large number of explicit constructions for T^*(2,7,v)-codes with v<2350 are also presented     

New method for wideband excitation of interdigital surface-wave transducers

A new method of designing coupled resonator networks for wideband excitation of interdigital surface-wave transducers is described. The elements of the tuning network are chosen, using an optimisation computer program. The insertion loss is minimised over the bandwidth of interest. For interdigital transducers on a monolithic zinc-oxide-on-silicon structure with ?v/v = 0.0036, a fractional bandwidth of 20% can be obtained. For a narrow-acoustic-beam interdigital transducer on a LiNbO3 halfspace with ?v/v = 0.022, a fractional bandwidth of 40% can be obtained. The design of the coupled resonator network takes into consideration the variation of the transducer acoustic impedance with frequency.     

Personal Imaging and lookpainting as tools for personal documentary and investigative photojournalism

A means and apparatus for covert capture of extremely highresolution photorealistic images is presented. The apparatus embodies a new form of userinterface – instead of the traditional point and click metaphor which was thought to be the simplest photography had to offer, what is proposed is a look metaphor in which images are generated through the natural process of looking around, in a manner that does not require conscious thought or effort. These lookpaintings become photographic/videographic memories that may, at times, exceed the quality attainable with even large and cumbersome professional photographic film cameras, yet they may be captured through a device that resembles ordinary sunglasses. The method is based on longterm psychophysical adaptation using a covert sunglassbased realitymediating apparatus, together with two new results in image processing. The first new result is a means of estimating the true projective coordinate transformation between successive pairs of images, and the second is that of estimating, to within a single unknown scalar constant, the quantity of light arriving at the image plane. Furthermore, what is captured is more than just a picture. The resulting environment map may be explored by one or more remote participants who may also correspond and interact with the wearer during the actual shooting process, giving rise to computer supported collaborative (collective) photography, videography, shared photographic/videographic memory, etc.     

Multi-Value Voltage-to-Voltage Converter Using a Multi-Stage Symmetrical Charge Pump for On-Chip EEPROM Programming

A fully integrated multi-stage symmetrical structure chargepump and its application to a multi-value voltage-to-voltage converterfor on-chip EEPROM programming are presented. The multi-valuevoltage-to-voltage converter is designed to offer two output voltages,power supply and triple power supply alternatively, which is neededfor a memory array. A dynamic analysis of the multi-stage symmetricalstructure charge pump and an optimization design in terms of circuitarea are also given. The circuit is implemented in a 1.2 CMOSprocess and the measurement results show that a voltage pulse as shortas 5 s with a rise time of 3 s is obtained. For a 5 V powersupply and with a resistive charge of 100 k, the programmingoutput voltage can reach as high as 11 V and output current forprogramming is over 110 A, which are high enough to program thememory cell.