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By analysing the key factors affecting the safety of the railway, this study aims to construct an information system to monitor safety performances of China National Railway networks. For each type of asset, there is a monitoring system. To integrate individual system information into a common information platform, it is proposed to use advanced computer network and information processing technology...
In magnetic recording, overwrite (OVW) measures how well the old data is suppressed by the new data [1]. In perpendicular recording, OVW is typically gauged by overwriting a high-frequency data pattern (e.g. 2T) with a low-frequency data pattern (e.g. 13T), and the OVW is called Reverse OVW (ROVW) [2]. It is frequently observed that higher OVW doesn't lead to higher Signal to Noise Ratio (SNR) or...
Nanocomposite magnets containing soft and hard magnetic phases have attracted immense attention for energy-related and biomedical applications. In particular, good control of the soft and hard phases at the nanoscale in the composites is of great importance for eective exchange coupling, allowing us to make the best of the strengths of soft and hard magnetic phases and to optimize the magnetic properties...
The voids at the glass frit bonding interface and inside the frit layer not only provide leakage pathways to deteriorate the sealing performance, but also reduce the effective contact area of the bonding interface to decrease the bonding strength. In this research, the micro composite glass frit bonding structure with redundant bleeding frit and bonding gap controllable was designed as the model to...
A 3D process model shows the manufacturing information intuitively in different machining stages. Efficiently and easily constructing 3D process model is one of the most important key technologies in 3D computer aided process planning system and it meets the requirements of the current 3D manufacturing environment. Thus, this paper focuses on creating the 3D process models (3D-PMs) based on the backward...
High-capacity generators and low load grid with a large proportion of wind power have high-frequency problem in isolated network. Moreover, optional control measures have large discrete and their adaptation intervals of frequency emergency control are rather small. It is hard to find suitable security combination ways of shearing generators simply by emergency control. An identification method to...
The research on variable frequency system mainly focuses on the developing of system performance, while the negative effects of the system is ignored. The bearing currents issue is a typical negative effect. In this paper, a lumped common mode model of a variable frequency induction motor driven by PWM inverter is proposed and the formulas of the key parameters in the model are presented. By researching...
The design of a high power gyroklystron amplifier operating with circular TE011 cavity modes is presented. The amplifier will be driven by a 70-kV, 6-A electron beam with a pitch angle (vt/vz) of 1.4 and velocity spread of 2.4% generated by a double-anode magnetron injection gun (MIG). The amplifier is predicted by particle-in-cell simulation to generated 145 kW at 94.1GHz with 35% efficiency, 38-dB...
The design of a high power gyroklystron amplifier operating with circular TE011 cavity modes is presented. The amplifier will be driven by a 70-kV, 6-A electron beam with a pitch angle (vt/vz)of 1.4 and velocity spread of 2.4% generated by a double-anode magnetron injection gun (MIG). The amplifier is predicted by particle-in-cell simulation to generated 145 kW at 94.1GHz with 35% efficiency, 38-dB...
Although innovation and corporate social responsibility (CSR) is becoming two major interrelated research topics, the interplay between them remains poorly understood. Thus, we examined the role of CSR on the different processes of innovation in an empirical study. Using a sample of Chinese firms, this study shows that CSR can strengthen the positive linkage between R&D investment and innovation...
In this paper we reveal the first time-reversal-invariant topological metamaterial exhibiting robust photonic surface states protected against disorder on all length scales. By combining chirality and hyperbolicity we show that polarization eigenstates with opposite handedness can become well separated in k-space leading to a new form of topological order.
TiN/HfO2/Pt resistive switching (RS) devices were fabricated with TiN top electrodes deposited in various Ar:N2 ambient. Strong relevance between ambient Ar:N2 ratio and electrical performance was demonstrated. This correlation was attributed to the difference in TiN crystal orientation, which has strong dependence on and can be controlled by ambient Ar:N2 ratio during deposition. Electrical measurement...
UV illumination switch is often utilized for pulse sharpening in large pulsed power devices. A lot of work has been done for UV illumination switch under nanosecond pulse1 while the switch under microsecond pulse may show different performance2. The purpose of this study is to figure out the breakdown characteristics of UV illumination switch under microsecond pulse. To analyse the development of...
With rapid development of pulse power technology, two-electrode gas spark switch has broadened its application in industrial fields, such as the extraction of unconventional gas resources. Thus, the repetitive switch requests high current capability, low breakdown voltage dispersancy, and long lifetime in an airtight chamber without gas blowing system or electrode cooling system. The purpose of this...
The two-electrode switches are the simplest and most commonly used closing switches in pulse power systems. Some researchers have designed a series of two electrodes spark-gap switches with many methods to promote insulation recovery for a stable self-breakdown voltage (Ub). But few studies have done on high-power repetitive spark-gap switches under adverse conditions, which means the switch works...
Switch is one of the key components in the pulsed power system. The two-electrode spark-gap switch made of alloy Cu-W has many advantages such as high current capability, long lifetime, and stability. Many researches have established a series of models of electrode erosion for failure prediction. Few of them considered adverse conditions, which means the switch works in a small airtight cavity without...
In this study, a cylindrical glass tube for near-field electrospinning (NFES) with multi-spinnerets is modified to fabricate polyvinylidene fluoride (PVDF) nanofibers on polyethylene terephthalate (PET) in large area. For the process, the traditional NFES is replaced by micro-drills technology which is used to design multi-spinnerets and drill spinnerets on the solder balls. PVDF solutions were formulated...
A dual-parameter optical sensor is demonstrated by connecting together a fiber Bragg grating and a no-core fiber. The hybrid configuration permits the detection of the temperature and the external refractive index.
A liquid-level indicator by using an etched chirped-fiber Bragg grating is proposed for monitoring a water level which sensing mechanism is based on the position variation of the interface between two different-index mediums.
This paper proposes a novel numerical integration method based on two-stage diagonally implicit Runge-Kutta (2S-DIRK) to solve the transient stability constrained optimal power flow (TSCOPF). The 2S-DIRK is an implicit trapezoidal method with the second-order accuracy, and its numerical stability is S-stable and then superior to other trapezoidal methods. Therefore, the 2S-DIRK method is used in this...
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