748 research outputs found
Has the Restructuring of Chinese Central Stated-Owned Enterprises Achieved the Goal of International Expansion?
Using the difference-in-differences method, we examine the internationalization effects of the restructuring of Chinese Central State-owned Enterprises (CCSOEs) during the years 2003 and 2016. We find that restructured CCSOEs have not achieved a higher degree of internationalization. Indeed, the higher the degree of internationalization after the CCSOE restructuring, the worse the firm’s performance. Overall, the results suggest that the Chinese government’s attempt to promote CCSOE internationalization through restructuring has not achieved its goal. Rather than governmental support and intervention, accelerating market-oriented reforms, weakening or eliminating administrative monopolies in the domestic market, and reducing the monopoly profits of CCSOEs in the domestic market could be more effective approaches to promote CCSOE internationalization
Beampattern-Based Tracking for Millimeter Wave Communication Systems
We present a tracking algorithm to maintain the communication link between a
base station (BS) and a mobile station (MS) in a millimeter wave (mmWave)
communication system, where antenna arrays are used for beamforming in both the
BS and MS. Downlink transmission is considered, and the tracking is performed
at the MS as it moves relative to the BS. Specifically, we consider the case
that the MS rotates quickly due to hand movement. The algorithm estimates the
angle of arrival (AoA) by using variations in the radiation pattern of the beam
as a function of this angle. Numerical results show that the algorithm achieves
accurate beam alignment when the MS rotates in a wide range of angular speeds.
For example, the algorithm can support angular speeds up to 800 degrees per
second when tracking updates are available every 10 ms.Comment: 6 pages, to be published in Proc. IEEE GLOBECOM 2016, Washington,
D.C., US
Design of Reconfigurable Intelligent Surface-Aided Cross-Media Communications
A novel reconfigurable intelligent surface (RIS)-aided hybrid
reflection/transmitter design is proposed for achieving information exchange in
cross-media communications. In pursuit of the balance between energy efficiency
and low-cost implementations, the cloud-management transmission protocol is
adopted in the integrated multi-media system. Specifically, the messages of
devices using heterogeneous propagation media, are firstly transmitted to the
medium-matched AP, with the aid of the RIS-based dual-hop transmission. After
the operation of intermediate frequency conversion, the access point (AP)
uploads the received signals to the cloud for further demodulating and decoding
process. Based on time division multiple access (TDMA), the cloud is able to
distinguish the downlink data transmitted to different devices and transforms
them into the input of the RIS controller via the dedicated control channel.
Thereby, the RIS can passively reflect the incident carrier back into the
original receiver with the exchanged information during the preallocated slots,
following the idea of an index modulation-based transmitter. Moreover, the
iterative optimization algorithm is utilized for optimizing the RIS phase,
transmit rate and time allocation jointly in the delay-constrained cross-media
communication model. Our simulation results demonstrate that the proposed
RIS-based scheme can improve the end-to-end throughput than that of the
AP-based transmission, the equal time allocation, the random and the discrete
phase adjustment benchmarks
The Design of Wireless Smart Home System based on ZigBee
Abstract. A functional and flexible wireless Smart Home system that based on GSM short message is presented. The design can control and monitor household equipments and environmental conditions. It uses the TMS320VC5402, CC2430 as the core hardware devices. Through ZigBee and the GSM integration, Smart Home remote monitoring and control are implemented. It has reflected the characteristic of low cost, low power dissipation, great practical and good scalability. All this work is significant for enhancing the actual application level and research level of Smart home control system further more
Energy Efficiency Oriented Design Method of Power Management Strategy for Range-Extended Electric Vehicles
The energy efficiency of the range-extended electric bus (REEB) developed by Tsinghua University must be improved; currently, the energy management strategy is a charge-deplete-charge-sustain (CDCS) strategy, which exhibits low energy efficiency on the demonstration model. To improve the energy efficiency and reduce the operating cost, a rule-based control strategy derived from the dynamic programming (DP) strategy is obtained for the Chinese urban bus driving cycle (CUBDC). This rule is extracted by the power-split-ratio (PSR) from the simulation results of the dynamic powertrain model using the DP strategy. By establishing the REEB dynamic models in Matlab/Simulink, the control rule can be achieved, and the power characteristic of powertrain, energy efficiency, operating cost, and computing time are analyzed. The simulation results show that the performance of the rule-based strategy presented in this paper is similar to that of the DP strategy. The energy efficiency can be improved greatly compared with that of the CDCS strategy, and the operating cost can also be reduced
Highly efficient triazine/carbazole-based host material for green phosphorescent organic light-emitting diodes with low efficiency roll-off
Two novel triazin/carbazole-based host materials were designed and synthesized, which demonstrated outstanding EL performance with maximum CE, PE and EQE of 69.3 cd A−1, 54.2 lm W−1 and 21.9%, respectively.</p
General survey of Fructus Psoraleae from the different origins and chemical identification of the roasted from raw Fructus Psoraleae
Fructus Psoraleae, a traditional Chinese medicine, is widely used for preventing and treating various diseases such as vitiligo, osteoporosis and psoriasis. Coumarin, such as psoralenoside, isopsoralenoside, psoralen and isopsoralen, are important compounds in Fructus Psoraleae. In our study, ultra performance liquid chromatography coupled with diode array detector was employed for an excellent method validation for simultaneous quantification of psoralenoside, isopsoralenoside, psoralen and isopsoralen, which was further applied in performing general survey of Fructus Psoraleae from the different origins and chemical identification of the roasted from raw Fructus Psoraleae in the light of illuminating the transformed rule of psoralenoside and isopsoralenoside. There is a reciprocal relationship between (iso)psoralenoside and (iso)psoralen, and the total content remains balance in Fructus Psoraleae from the different origins. In addition, we found that (iso)psoralenoside in the powder of the raw Fructus Psoraleae could be easily transformed into (iso)psoralen in methanol aqueous solution, especially above 50% water, rather than the roasted one. Thus, we proposed a hypothesis that transformation between (iso)psoralenoside and (iso)psoralen was hindered by inactivation of β-glucosidase in the process of roasting Fructus Psoraleae, which was further verified by observing transformation of (iso)psoralenoside under the different conditions, such as temperature, pH and β-glucosidase. Therefore, we developed a feasible method to distinguish the roasted from raw Fructus Psoraleae by observing conversion from (iso)psoralenoside to (iso)psoralen in 50% methanol aqueous solution. In summary, these results pave the way for elevating quality standard for Fructus Psoraleae and distinguishing the salt-processed from raw Fructus Psoraleae
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