A covering construction for packing disjoint copies of the Hoffman‐Singleton graph into K50

In this note we show how coverings induced by voltage assignments can be used to produce packings of disjoint copies of the Hoffman‐Singleton graph into K₅₀. © 2003 Wiley Periodicals, Inc. J Combin Designs 11: 408–412, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10049     

High Voltage Pulse Power and the Technics for the Capacitor Power-Storage Type

Lower hybrid wave （LHW）, electro cyclotron （EC） and neutral beam injection （NBI） etc. are the important methods of auxiliary heating. They would be devoted to the HL-2A tokamak step by step. In order to satisfy the debug of each system and the need of the experiment, the system should be equipped with high voltage pulse power （HVPP） according to the requirement.     

气体放电等离子体特性测量I-V曲线不对称性的研究

利用气体放电双探针法研究了等离子体的I-V曲线中的电流I相对于电压V轴交点的不对称性,并提出2种可能的解释:一认为是由于两探针表面积不同引起的;二认为是由于探针所在处等离子体电位不等引起的.本文利用仪器的工艺误差和调换放电管电压的方法,对提出的2种可能原因分别进行验证,并指出第二种解释的合理性,并对其进行了理论分析.     

用图像分析限流和分压接法中滑动变阻器的选取

借助Ux-Rap图像分析得出滑动变阻器的选取原则:控制电路采用限流接法时,要求滑动变阻器的最大阻值与被测电阻的阻值接近,即接近为原则;控制电路采用分压式接法时,滑动变阻器的最大阻值应远小于被测电阻的阻值,故在分压接法中,应选择阻值较小而额定电流较大的滑动变阻器.     

Ab initio study of sodium intercalation into metal oxides

Using the full-potential linearized augmented plane wave (FP-LAPW) method, we have studied the effect of chemistry on the average intercalation voltage (AIV) caused by the Na ions intercalating into transition metal oxides. The effect of transition metal was systematically studied by varying M=Co, Ni and Mn in NaMO₂ and fixing the α-NaFeO₂ layered structure. The effect of the guest atoms into the host material is discussed in terms of the structural and electronic properties. Comparatively to Li intercalation, a significant electron transfer towards transition metal was found. This observation suggests that the transition metal contribute to the AIV determination and confirms the common assumption that intercalated electron reduces M⁴⁺ to M³⁺.     

On the effect of a longitudinal magnetic field on oscillatory characteristics of a subnormal region in discharge in argon

Oscillating nature of current pulses under d.c. excitation in subnormal region with longitudinal magnetic field at pressure range 0.20 torr to 0.85 torr have been studied. The frequency, bandwidth, peak-peak voltage, cut-off current and rise time of the current pulses have been observed with pressure, average tube current and magnetic field. A study of these oscillograms in magnetic field, average tube current and pressure are presented. The probable mechanism for the generation of oscillation based on space-charge field modification with magnetic field is discussed     

Electrochemical instability of bis(trifluoromethylsulfonyl)imide based ionic liquids as solvents in high voltage electrolytes for potassium ion batteries

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Influence of Urbach Energy,Temperature, and Longitudinal Position in the Active Layer on Carrier Diffusion Length in Perovskite Solar Cells

The diffusion length of charge carriers in the active layer of a perovskite solar cell (PSC) of the structure Glass/PEDOT: PSS/CH₃NH₃PbI₃/PC60BM/Al is modelled. It is found that the diffusion length depends on the position x in the active layer measured from the PEDOT: PSS interface, Urbach energy and temperature. By varying the voltage in the range from zero to , it is shown that the dependence of diffusion length on the position x in the active layer reduces at higher voltage. The combined influence of applied voltage and temperature on the diffusion length of charge carriers is investigated and it is found that in the low voltage range the diffusion length is temperature independent, but it becomes significantly temperature dependent at higher voltages. Also, it is found that the diffusion length decreases as the applied voltage increases and this reduction becomes much more significant at higher voltage and temperatures. The combined influence of applied voltage and Urbach energy on diffusion length of charge carriers reveals that the diffusion length decreases when both the applied voltage and Urbach energy increase. However, the reduction in the diffusion length due to the increase in Urbach energy becomes less significant at higher voltage.     

基于定向纳米碳管气体放电的气敏传感器研究

介绍了一种基于定向纳米碳管的气敏传感器,以生长定向纳米碳管的氧化铝模板作为阳极,铝板作为阴极,利用纳米碳管的尖端发射效应,在较低的电压下使气体产生放电现象。通过对纳米碳管在气体中击穿电压和放电电流的测量,实现对气体的定性定量检测。同时纳米碳管气敏传感器还具有体积小、灵敏度高、稳定性好、响应速度快、在常温常压下即可进行检测等优点,具有较好的应用前景。     

Surface analysis of plasma‐treated polydimethylsiloxane by x‐ray photoelectron spectroscopy and surface voltage decay

Surface states of polydimethylsiloxane (PDMS) treated by plasma were investigated by x‐ray photoelectron spectroscopy and surface voltage decay. X‐ray photoelectron spectroscopy confirmed the formation of a silica‐like (SiO_x, x = 3–4) oxidative surface layer. This layer increased in thickness with increasing exposure duration of plasma. Plasma exposure lowers the surface resistivity from 1.78 × 10¹⁴ to 1.09 × 10¹³ Ω □^?1 with increasing plasma treatment time. By measuring the decay time constant of surface voltage, the calculated surface resistivity was compared with the value measured directly by a voltage–current method; good agreement between the two methods was obtained. It was observed that plasma treatment led to a decrease in the thermal activation energy of the surface conduction from 31.0 kJ mol^?1 for an untreated specimen to 21.8 kJ mol^?1 for a plasma‐treated specimen for 1 h. Our results allow the examination of effects of plasma on the electrical properties of PDMS. Copyright © 2003 John Wiley & Sons, Ltd.