92 research outputs found
Chaowei and Shouzhi During the Han Period
No full textThe author of this paper asserts that shouzhi 綬制 (a rank order system of different colored sashes) of the Han 漢 dynasty corresponded to the rank order conceived to have existed in the Zhou 周 period: wang－gong－qing－dafu－shi 王－公－卿－大夫－士; i.e. zhouzhi 周制. In this paper, the author tries to prove that chaowei 朝位 was arranged according to zhouzhi, and that chaowei was indivisibly connected with shouzhi.First, by analyzing the usage of the term ‘chaowei’ in zhengshi 正史, it is shown that the term chaowei meant the order of seats at a morning gathering at Court, and also that the idioms wei (ci) mou 位 (次) 某 and wei (ci) zai mou 位 (次) 在某 were used until the Qing 清 period in order to indicate chaowei.Secondly, because descriptions about chaowei increased in the Han period, the author examines the rank order of the Han dynasty, in which chaowei was established. In the Han period, descriptions contained chaowei generally accompanied one of the words wang, gong, qing, or dafu, meaning that chaowei was arranged according to zhouzhi.Lastly, from some of the descriptions it becomes clear that chaowei was related to the colors of shou 綬 sashes. Since shouzhi of the Han dynasty corresponded to zhouzhi, it follows that shouzhi indicated chaowei, which was equal to zhouzhi.The author suspects the possibility that chaowei integrated the rank order of guanzhi 官秩and ershidengjue 二十等爵, but we need to examine this point further.journal articl
Bandwidth Optimization Design of a Multi Degree of Freedom MEMS Gyroscope
No full textA new robust multi-degree of freedom (multi-DOF) MEMS gyroscope is presented in this paper. The designed gyroscope has its bandwidth and amplification factor of the sense mode adjusted more easily than the previous reported multi-DOF MEMS gyroscopes. Besides, a novel spring system with very small coupling stiffness is proposed, which helps achieve a narrow bandwidth and a high amplification factor for a 2-DOF vibration system. A multi-DOF gyroscope with the proposed weak spring system is designed, and simulations indicate that when the operating frequency is set at 12.59 kHz, the flat frequency response region of the sense mode can be designed as narrow as 80 Hz, and the amplification factor of the sense mode at the operating frequency is up to 91, which not only protects the amplification factor from instability against process and temperature variations, but also sacrifices less performance. An experiment is also carried out to demonstrate the validity of the design. The multi-DOF gyroscope with the proposed weak coupling spring system is capable of achieving a good tradeoff between robustness and the performance
Fabrication and characterisation of polysilicon-based clamped-clamped filter
No full textThe rapid growth of micromaching technology makes the miniaturized or integrated MEMS resonator or filter become possible. This paper reports on the fabrication and characterization of the polysilicon-based RF MEMS filter, comprised of the two clamped-clamped resonators coupled with the micro dimensions beam. The surface micromaching technology has been adopted to fabricate the clamped-clamped filter. The fabricating process and the optimization of the typical micromaching process for the MEMS RF filter are illustrated in detail. After the fabrication, the resonating characteristics are measured. The center frequency of30 MHz of the micromechanical bandpass filter is demonstrated.?(2011) Trans Tech Publications
Feed-through cancellation of a MEMS filter using the difference method and analysis of the induced notch
No full textDesign and Simulation of A Novel Piezoelectric AlN-Si Cantilever Gyroscope
No full textA novel design of piezoelectric aluminum nitride (AlN)-Si composite cantilever gyroscope is proposed in this paper. The cantilever is stimulated to oscillate in plane by two inverse voltages which are applied on the two paralleled drive electrodes, respectively. The whole working principles are deduced, which based on the piezoelectric equation and elastic vibration equation. In this work, a cantilever gyroscope has been simulated and optimized by COMSOL Multiphysics 5.2a. The drive mode frequency is 87.422 kHz, and the sense mode frequency is 87.414 kHz. The theoretical sensitivity of this gyroscope is 0.145 pm/◦/s. This gyroscope has a small size and simple structure. It will be a better choice for the consumer electronics
Design and Fabrication of a Novel Poly-Si Microhotplate with Heat Compensation Structure
No full textI Microhotplates are critical devices in various MEMS sensors that could provide appropriate operating temperatures. In this paper, a novel design of poly-Si membrane microhotplates with a heat compensation structure was reported. The main objective of this work was to design and fabricate the poly-Si microhotplate, and the thermal and electrical performance of the microhotplates were also investigated. The poly-Si resistive heater was deposited by LPCVD, and phosphorous doping was applied by in situ doping process to reduce the resistance of poly-Si. In order to obtain a uniform temperature distribution, a series of S-shaped compensation structures were fabricated at the edge of the resistive heater. LPCVD SiNx layers deposited on both sides of poly-Si were used as both the mechanical supporting layer and the electrical isolation layer. The Pt electrode was fabricated on the top of the microhotplate for temperature detection. The area of the heating membrane was 1 mm × 1 mm. Various parameters of the different size devices were simulated and measured, including temperature distribution, power consumption, thermal expansion and response time. The simulation and electrical–thermal measurement results were reported. For microhotplates with a heat compensation structure, the membrane temperature reached 811.7 °C when the applied voltage was 5.5 V at a heating power of 148.3 mW. A 3.8 V DC voltage was applied to measure the temperature distribution; the maximum temperature was 397.6 °C, and the area where the temperature reached 90% covered about 73.8% when the applied voltage was 3.8 V at a heating power of 70.8 mW. The heating response time was 17 ms while the microhotplate was heated to 400 °C from room temperature, and the cooling response time was 32 ms while the device was recovered to room temperature. This microhotplate has many advantages, such as uniform temperature distribution, low power consumption and fast response, which are suitable for MEMS gas sensors, humidity sensors, gas flow sensors, etc
The imposition of cross-border digital activities in China
No full textLa numérisation de l’économie pose de sérieux défis à la fois au système fiscal international traditionnel et au système fiscal national. Comme beaucoup de pays, la Chine est confrontée aux défis fiscaux soulevés notamment par le développement rapide des activités numériques transfrontalières. En réponse aux problèmes fiscaux liés à l'économie numérique, des organisations internationales comme l'OCDE, l'Union européenne (UE) et le G20 ont effectué des efforts continus pour explorer les solutions. Notre étude se concentre sur l’imposition des services numériques transfrontaliers en Chine. Nous nous demandons si les mesures déjà prises par la Chine sont à la hauteur des défis fiscaux posés par les activités numériques transfrontalières et quelles réformes fiscales devraient être envisagées qui soient à la fois cohérentes avec les nouvelles règles internationales à l’élaboration desquelles la Chine a activement participé et capables d’apporter des solutions aux problèmes spécifiques de la Chine. En commençant par identifier les défis fiscaux soulevés par les transactions numériques transfrontalières tant au niveau international que national en Chine, nous étudions dans un second temps les solutions qui devraient être apportées en réponse à ces défis. Dans les deux parties de notre recherche, notre étude couvre à la fois les impôts directs et les impôts indirects, les règles de fond comme les règles de forme. Le fait que les défis fiscaux liés à l’économie numérique auxquels la Chine est confrontée sont, dans une large mesure, communs au niveau international nous amène à consacrer une partie de notre étude aux questions communes avant d’examiner les questions spécifiques à la Chine. Enfin, certaines activités tout à fait récentes et émergentes rendues possibles par le développement de la technologie numérique, telles que les crypto-actifs et le métavers, ont également attiré notre attentionThe digitalisation of the economy poses serious challenges to both the traditional international tax system and the National tax system. Like many countries, China is facing tax challenges raised in particular by the rapid development of cross-border digital activities. In response to the tax problems associated with the digital economy, international organisations such as the OECD, the European Union (EU) and the G20 have made continuous efforts to explore solutions. Our study focuses on the taxation of cross-border digital services in China. We consider that whether the measures already taken by China are commensurate with the tax challenges posed by cross-border digital activities and what tax reforms should be considered that are both consistent with the new international rules in whose development China has actively participated and capable of providing solutions to China's specific problems. By first identifying the tax challenges raised by cross-border digital transactions at both international and domestic levels in China, then we explore the solutions that should be provided in response to these challenges. In both parts of the research, our study covers both direct and indirect taxes, both substantive and formal rules. The fact that the tax challenges related to the digital economy that China faces are, to a large extent, common internationally leads us to devote part of our study to common issues before examining issues specific to China. Finally, some very recent and emerging activities made possible by the development of digital technology, such as crypto-assets and metaverses, have also attracted our attentio
Revealing the Tunable Effects of Single Metal Atoms Supported on Nitrogen-Doped Carbon Nanotubes during NO Oxidation from Microkinetic Simulation
No full textNO oxidation is one of the most used
catalytic routes
for NOx removal, which is a pressing environmental
issue. As an emerging new class of catalysts, single atom catalysts
(SACs) have demonstrated competitive catalytic capabilities compared
with conventional noble metals regarding NO oxidation. It is of pivotal
importance to understand the working principle and screen the best
candidate SAC in NO oxidation. To this end, five SACs (Fe, Co, Ni,
Cu, and Pt) have been examined and compared, which exhibit unique
and hitherto unusual catalytic properties for NO oxidation as revealed
from first principles calculations. The turnover frequency (TOF) of
the Co SAC is estimated to be 0.33 s–1, which exceeded
that of the conventional NO oxidation catalyst. The nitrogen dopants
on the carbon nanotube support effectively adjust the properties of
metal atoms, which significantly enhanced the adsorption of reactants.
The trend of calculated adsorption energies is consistent with the
variable d-band center of single metal atoms. It was found Eley–Rideal
(E–R) is more favorable than Langmuir–Hinshelwood (L–H)
for all SACs. The calculated TOF of SACs is well correlated with the
oxygen adsorption energy. The current work demonstrates the great
potential of SACs in NO oxidation and verified the strategy of carbon
support dopant engineering
Resolving the Mechanism Complexity of Oxidative Dehydrogenation of Hydrocarbons on Nanocarbon by Microkinetic Modeling
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