A bulk micromachined gyroscope with improved quality-factors at atmospheric pressure

2007 ◽  
Author(s):  
Weiping Chen ◽  
Hong Chen ◽  
Xiaowei Liu ◽  
Tian Han ◽  
Hao Wang
Keyword(s):  
Atmospheric Pressure ◽  
Quality Factors ◽  
Micromachined Gyroscope

Design and Simulation of Capacitive Micromechaned Gyroscope

2011 ◽  
Vol 211-212 ◽  
pp. 909-913
Author(s):  
Yun Bo Shi ◽  
Xing Juan Zhao ◽  
Jun Tang ◽  
Jun Liu ◽  
Rui Rong Wang
Keyword(s):  
Atmospheric Pressure ◽  
Simulation Analysis ◽  
High Sensitivity ◽  
Drive Mode ◽  
Close Match ◽  
High Q ◽  
Air Damping ◽  
Large Numbers ◽  
Detection Mode ◽  
Micromachined Gyroscope

By researching and investigating the structure of capacitive gyroscopes, A novel capacitive micromachined gyroscope is proposed and the structure is designed. The method of electrostatic comber drive, capacitive detection of bar structure is used for the structure, and these make the gyroscope high sensitivity. The main air damping of the drive mode and detection mode is slide film damping, it is possible to make the gyroscope achieve high Q-values at atmospheric pressure. The decoupled gyroscope is designed, too. By large numbers of simulation analysis， frequencies of the first six steps mode are gained, nature frequencies of drive mode and sense mode of gyroscope are a close match, and rationality of the structure is validated. At last, the structure encapsulated is presented.

Design of a Novel Micromachined Gyroscope with Compensatory Capacitance

2007 ◽  
Vol 353-358 ◽  
pp. 2778-2781
Author(s):  
Wei Ping Chen ◽  
Hong Chen ◽  
Tian Han ◽  
Xiao Wei Liu ◽  
Hong Yu Wang
Keyword(s):  
Differential Capacitance ◽  
Frame Structure ◽  
Dual Frame ◽  
Stable Operation ◽  
Quality Factors ◽  
Interface Circuits ◽  
Resonant Frequencies ◽  
System Sensitivity ◽  
Gyroscope System ◽  
Micromachined Gyroscope

This paper presents a novel bulk micromachined gyroscope with the compensatory capacitance. Independent driving and sensing beams and a dual-frame structure are adopted to decouple mechanically for stable operation. The method of electrostatic push-pull drive and capacitive sense combs based on the slide film damping are applied to obtain a large driving force and high quality factors. The compensatory capacitance is designed to compensate the deviations of sensing differential capacitance from fabrications. The designed gyroscope has matched resonant frequencies of 2187Hz and 2206Hz for the drive and sense modes, respectively. Considering the noise of interface circuits, the gyroscope system sensitivity can reach 14.2mv/o/s, theoretically.

scholarly journals Effect of Axial Force on the Performance of Micromachined Vibratory Rate Gyroscopes

Sensors ◽  
2010 ◽  
Vol 11 (1) ◽  
pp. 296-309 ◽  
Author(s):  
Zhanqiang Hou ◽  
Dingbang Xiao ◽  
Xuezhong Wu ◽  
Peitao Dong ◽  
Zhihua Chen ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Axial Force ◽  
Great Influence ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Vibratory Gyroscopes ◽  
Thermal Expansion Coefficients ◽  
Micromachined Gyroscope ◽  
Experimental Values ◽  
Increasing Temperature

It is reported in the published literature that the resonant frequency of a silicon micromachined gyroscope decreases linearly with increasing temperature. However, when the axial force is considerable, the resonant frequency might increase as the temperature increases. The axial force is mainly induced by thermal stress due to the mismatch between the thermal expansion coefficients of the structure and substrate. In this paper, two types of micromachined suspended vibratory gyroscopes with slanted beams were proposed to evaluate the effect of the axial force. One type was suspended with a clamped-free (C-F) beam and the other one was suspended with a clamped-clamped (C-C) beam. Their drive modes are the bending of the slanted beam, and their sense modes are the torsion of the slanted beam. The relationships between the resonant frequencies of the two types were developed. The prototypes were packaged by vacuum under 0.1 mbar and an analytical solution for the axial force effect on the resonant frequency was obtained. The temperature dependent performances of the operated mode responses of the micromachined gyroscopes were measured. The experimental values of the temperature coefficients of resonant frequencies (TCF) due to axial force were 101.5 ppm/°C for the drive mode and 21.6 ppm/°C for the sense mode. The axial force has a great influence on the modal frequency of the micromachined gyroscopes suspended with a C-C beam, especially for the flexure mode. The quality factors of the operated modes decreased with increasing temperature, and changed drastically when the micromachined gyroscopes worked at higher temperatures.

Temperature and Relative Humidity Dependence of Quality Factors of MEMS Cantilever Resonators in Atmospheric Pressure

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Quoc Cuong Le ◽  
Minh Truong Phan ◽  
Xuan Thang Trinh ◽  
Huu Ly Truong ◽  
Vo Ke Thanh Ngo ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Atmospheric Pressure ◽  
Quality Factors ◽  
Humidity Dependence

A High-Voltage Terminal for a Field-Emission Gun

1972 ◽  
Vol 30 ◽  
pp. 428-429
Author(s):  
N. F. Ziegler
Keyword(s):  
Field Emission ◽  
High Voltage ◽  
Atmospheric Pressure ◽  
Power Supplies ◽  
High Coherence

A high-voltage terminal has been constructed for housing the various power supplies and metering circuits required by the field-emission gun (described elsewhere in these Proceedings) for the high-coherence microscope. The terminal is cylindrical in shape having a diameter of 14 inches and a length of 24 inches. It is completely enclosed by an aluminum housing filled with Freon-12 gas at essentially atmospheric pressure. The potential of the terminal relative to ground is, of course, equal to the accelerating potential of the microscope, which in the present case, is 150 kilovolts maximum.

Electron microscope characterization of MOCVD-grown gap layers on Si

1986 ◽  
Vol 44 ◽  
pp. 724-725
Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson
Keyword(s):  
Atmospheric Pressure ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Lattice Match ◽  
Si Substrates ◽  
Metal Organic ◽  
Good Lattice ◽  
Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Microstructure and reactivity of small metal particles: The role of Ce additives

1992 ◽  
Vol 50 (1) ◽  
pp. 318-319
Author(s):  
L.D. Schmidt ◽  
K. R. Krause ◽  
J. M. Schwartz ◽  
X. Chu
Keyword(s):  
Atmospheric Pressure ◽  
Noble Metals ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Chemical Shifts ◽  
Catalytic Converter ◽  
Structural Evolution ◽  
Single Particles ◽  
Small Metal Particles

The evolution of microstructures of 10- to 100-Å diameter particles of Rh and Pt on SiO2 and Al2O3 following treatment in reducing, oxidizing, and reacting conditions have been characterized by TEM. We are able to transfer particles repeatedly between microscope and a reactor furnace so that the structural evolution of single particles can be examined following treatments in gases at atmospheric pressure. We are especially interested in the role of Ce additives on noble metals such as Pt and Rh. These systems are crucial in the automotive catalytic converter, and rare earths can significantly modify catalytic properties in many reactions. In particular, we are concerned with the oxidation state of Ce and its role in formation of mixed oxides with metals or with the support. For this we employ EELS in TEM, a technique uniquely suited to detect chemical shifts with ∼30Å resolution.

Diet Quality, a Term Subject to Change over Time

2012 ◽  
Vol 82 (3) ◽  
pp. 144-147 ◽  
Author(s):  
Ibrahim Elmadfa ◽  
Alexa L. Meyer
Keyword(s):  
Diet Quality ◽  
Functional Foods ◽  
Disease Risk ◽  
Well Being ◽  
Industrialized Countries ◽  
Quality Factors ◽  
Long Time ◽  
Quality Diet ◽  
Important Quality ◽  
Health And Well Being

A high-quality diet is one of the foundations of health and well-being. For a long time in human history, diet was chiefly a source of energy and macronutrients meant to still hunger and give the strength for work and activities that were in general much harder than nowadays. Only few persons could afford to emphasize enjoyment. In the assessment of quality, organoleptic properties were major criteria to detect spoilage and oxidative deterioration of food. Today, food hygiene is a quality aspect that is often taken for granted by consumers, despite its lack being at the origin of most food-borne diseases. The discovery of micronutrients entailed fundamental changes of the concept of diet quality. However, non-essential food components with additional health functions were still barely known or not considered important until recently. With the high burden of obesity and its associated diseases on the rise, affluent, industrialized countries have developed an increased interest in these substances, which has led to the development of functional foods to optimize special body functions, reduce disease risk, or even contribute to therapeutic approaches. Indeed, nowadays, high contents of energy, fat, and sugar are factors associated with a lower quality of food, and products with reduced amounts of these components are valued by many consumers. At the same time, enjoyment and convenience are important quality factors, presenting food manufacturers with the dilemma of reconciling low fat content and applicability with good taste and appealing appearance. Functional foods offer an approach to address this challenge. Deeper insights into nutrient-gene interactions may enable personalized nutrition adapted to the special needs of individuals. However, so far, a varied healthy diet remains the best basis for health and well-being.

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