Excited States of Xanthene Analogues: Photofragmentation and Calculations by CC2 and Time‐Dependent Density Functional Theory

Action spectroscopy has emerged as an analytical tool to probe excited states in the gas phase. Although comparison of gas‐phase absorption properties with quantum‐chemical calculations is, in principle, straightforward, popular methods often fail to describe many molecules of interest—such as xanthene analogues. We, therefore, face their nano‐ and picosecond laser‐induced photofragmentation with excited‐state computations by using the CC2 method and time‐dependent density functional theory (TDDFT). Whereas the extracted absorption maxima agree with CC2 predictions, the TDDFT excitation energies are blueshifted. Lowering the amount of Hartree–Fock exchange in the DFT functional can reduce this shift but at the cost of changing the nature of the excited state. Additional bandwidth observed in the photofragmentation spectra is rationalized in terms of multiphoton processes. Observed fragmentation from higher‐lying excited states conforms to intense excited‐to‐excited state transitions calculated with CC2. The CC2 method is thus suitable for the comparison with photofragmentation in xanthene analogues.     

基于zigbee的养老院健康监护系统设计

针对养老院老人的监护需求,本文提出一种基于ZigBee无线通信技术的养老院健康监护方案,设计一个经济实用的低功耗ZigBee无线监测系统。系统各个节点以CC2530为核心,通过控制Pulse Sensor脉搏传感器、DS18B20体温传感器、XGZP6847血压传感器,采集老人的生命体征数据。数据通过监护中心进行监测与分析,如果超出健康范围,系统将进行语音提示并通知护工。实验表明该系统可以有效提高养老院的监护水平。     

基于CC2430的城市车辆限行系统研究

随着车辆的增多，城市交通拥堵越来越严重，影响了市民日常出行。实行车辆限行是缓解交通拥堵的有效方法。利用ChipconAS公司的射频芯片CC2430进行车辆无线识别，结合单片机与以太网实现远程通信，设计了一套根据车辆出行天数进行城市车辆限行的系统。为了获得车辆出行天数，对根据出行天数进行车辆限行的方法进行了论述，重点是系统的硬件设计，并对软件设计中的难点给出了说明。     

基于SimpliciTI无线链式火灾报警系统设计

介绍一种SimpliciTI技术，并实现了基于SimpliciTI的无线链式火灾报警系统。该系统在居住楼内或办公楼内、组成无线传感器网络，报警点通过无线链式通知周围报警系统，警戒可能涉及到的人群逃离。采用CC2430芯片和软件相结合，实现了火灾信息的及时最大范围内通知，有效避免了火灾等安全事故带来的损失。     

基于ZigBee的无线点菜系统

为了实现实时点餐,本文提出了一种基于ZigBee技术的无线点菜终端系统,并对系统的硬件和软件进行了详细的分析和设计,修改并移植了TI公司ZigBee 2006协议栈Z-Stack1.4.2-1.1.0,最后对该系统做了实际运行测试。此系统经扩展可应用于小型商店售货、仓储。     

非线性参量对扬声器谐振频率f0的影响

讨论了扬声器谐振频率f0测试的不确定性,对f0测试标准进行了解读,从非线性角度分析了扬声器谐振频率波动的根本原因,并给出了正确的测试方法。     

无线水位监测系统的设计与实现

为了解决一些河流、水库的水位监测地点不方便布线的实际问题,设计并实现了基于芯片CC2430的无线水位监测系统,同时设计了无线节点及相应的软件,减少了系统布线,开发出无线水位计算机监控软件,能够直观、及时地了解水位信息,便于系统的维护。     

Ab initio description of photoabsorption and electron transfer in a doubly-linked porphyrin-fullerene dyad

Structure, photoabsorption and excited states of two representative conformations obtained from molecular dynamics (MD) simulations of a doubly-linked porphyrin-fullerene dyad DHD6ee are studied by using both DFT and wavefunction based methods. Charge transfer from the donor (porphyrin) to the acceptor (fullerene) and the relaxation of the excited state are of special interest. The results obtained with LDA, GGA, and hybrid functionals (SVWN, PBE, and B3LYP, respectively) are analyzed with emphasis on the performance of used functionals as well as from the point of view of their comparison with wavefunction based methods (CCS, CIS(D), and CC2). Characteristics of the MD structures are retained in DFT optimization. The relative orientation of porphyrin and fullerene is significantly influencing the MO energies, the charge transfer (CT) in the ground state of the dyad and the excitation of ground state CT complex (g-CTC). At the same time, the excitation to the locally excited state of porphyrin is only little influenced by the orientation or cc distance. TD-DFT underestimates the excitation energy of the CT state, however for some cases (with relatively short donor-acceptor separations), the use of a hybrid functional like B3LYP alleviates the problem. Wavefunction based methods and CC2 in particular appear to overestimate the CT excitation energies but the inclusion of proper solvation models can significantly improve the results.     

基于ZigBee的无线传感器网络平台的设计

通过对ZigBee无线传感器网络技术的研究,采用Atmega128L和CC2420设计并实现了一个基于ZigBee无线传感器网络平台,并对该平台的硬件结构设计做出了详细的介绍,实验测试该平台具有低功耗、高可靠性,易组网及稳定性好等优势,具有广泛的应用前景。