scholarly journals Decreasing Frequency Splits of Hemispherical Resonators by Chemical Etching

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3772 ◽  
Author(s):  
Yuting Wang ◽  
Yao Pan ◽  
Tianliang Qu ◽  
Yonglei Jia ◽  
Kaiyong Yang ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Frequency Tuning ◽  
High Reliability ◽  
Quality Factors ◽  
Labor Input ◽  
Etching Method ◽  
Hemispherical Resonator ◽  
Frequency Split ◽  
Tuning Methods ◽  
First Time

The hemispherical resonator gyroscope (HRG) has attracted the interest of the world inertial navigation community because of its exceptional performance, ultra-high reliability and its potential to be miniaturized. These devices achieve their best performance when the differences in the frequencies of the two degenerate working modes are eliminated. Mechanical treatment, laser ablation, ion-beams etching, etc., have all been applied for the frequency tuning of resonators, however, they either require costly equipment and procedures, or alter the quality factors of the resonators significantly. In this paper, we experimentally investigated for the first time the use of a chemical etching procedure to decrease the frequency splits of hemispherical resonators. We provide a theoretical analysis of the chemical etching procedure, as well as the relation between frequency splits and mass errors. Then we demonstrate that the frequency split could be decreased to below 0.05 Hz by the proposed chemical etching procedure. Results also showed that the chemical etching method caused no damage to the quality factors. Compared with other tuning methods, the chemical etching method is convenient to implement, requiring less time and labor input. It can be regarded as an effective trimming method for obtaining medium accuracy hemispherical resonator gyroscopes.

Ni-MOF in-situ Decorating ZnO photoelectrode for photoelectrochemical water splitting

2018 ◽  
Vol 11 (04) ◽  
pp. 1850085 ◽  
Author(s):  
Zhen Qian Liu ◽  
Kejia Qiu ◽  
Hongye Bai ◽  
Fagen Wang ◽  
Yilin Ge ◽  
...  
Keyword(s):  
Water Splitting ◽  
Chemical Etching ◽  
Photocurrent Density ◽  
Photoelectrochemical Water Splitting ◽  
Photoelectrochemical Performance ◽  
Co Catalyst ◽  
Etching Method ◽  
First Time

The Ni-MOF as co-catalyst has been in-situ introduced on the surface of ZnO photoelectrode by chemical etching method for the first time, and the unique organic/inorganic heterostructure (Ni-MOF/ZnO) was applied for photoelectrochemical water splitting. The Ni-MOF could work as special co-catalyst to improve the kinetic and charges separation of ZnO electrode, and the photocurrent density of Ni-MOF/ZnO has increased to about 1.8 times than that of bare ZnO. The IPCE value of Ni-MOF/ZnO has been enhanced up to 11% (355[Formula: see text]nm, 0.5[Formula: see text]V vs Ag/AgCl). The proposed mechanism of charges transfer has been also discussed in-depth, according to the photoelectrochemical performance.

scholarly journals The control algorithm of whole angle mode for HRG based on the vector composition

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Wanliang Zhao ◽  
Yuxiang Cheng ◽  
Shaoliang Li ◽  
Lijun Song
Keyword(s):  
Control Algorithm ◽  
High Reliability ◽  
Energy Transition ◽  
Life Time ◽  
Mathematics Model ◽  
Operating Modes ◽  
Hemispherical Resonator ◽  
Order Of Magnitude ◽  
Electrostatic Control ◽  
Space Launcher

AbstractThe Hemispherical Resonator Gyroscope (HRG) has many advantages such as high precision, high reliability and long life-time, it is widely used in the space-launcher and the satellites. The HRG has been mechanized to operate in the distinct operating modes, the Force to Rebalanced (FTR) mode and the Whole Angle (WA) mode. In the paper, different from the traditional control algorithm is based on average methods which usually used for the WA mode, a new electrostatic control algorithm is presented, which based on the vector composition and decomposition method to control the equivalent drive force in order to track the phase of the standing wave. The mathematics model and the control algorithm are presented in the paper, and the hardware experimental circuit system is implemented, the HRG has a range of more than 300°/s with the linearity of 40 ppm. Meanwhile, the energy transition efficiency increases by an order of magnitude.

Luminescent small-diameter 3C-SiC nanocrystals fabricated via a simple chemical etching method

2007 ◽  
Vol 18 (36) ◽  
pp. 365603 ◽  
Author(s):  
J Zhu ◽  
Z Liu ◽  
X L Wu ◽  
L L Xu ◽  
W C Zhang ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Small Diameter ◽  
Etching Method ◽  
Simple Chemical

A Frequency-Tunable Comb Resonator Using Spring Tension and Compression Effects

2004 ◽  
Author(s):  
Ki Bang Lee ◽  
Albert P. Pisano ◽  
Liwei Lin
Keyword(s):  
Resonant Frequency ◽  
Bias Voltage ◽  
Frequency Tuning ◽  
Electrostatic Force ◽  
Voltage Change ◽  
Tension And Compression ◽  
Frequency Tunable ◽  
Frequency Changes ◽  
Compression Effects ◽  
First Time

A 2μm-thick frequency-tunable microresoantor capable of either increasing or decreasing its resonant frequency by a combination of Joule heating and electrostatic force has been successfully demonstrated for the first time. For the heating voltage increase from 0 to 2V under fixed bias voltage of 40V, the resonant frequency changes from 22.2kHz to 16.2kHz, resulting in the 27% reduction in the resonant frequency. For the bias voltage change from 20V to 40V under the heating voltage of 0V, the resonant frequency increase from 19.0kHz to 23.6kHz, resulting in the 24.2% increase in the resonant frequency. As such, this surface-micromachined microactuator could assist complicated frequency tuning for applications of microsensors and microactuators.

scholarly journals LITOS – a new balloon-borne instrument for fine-scale turbulence soundings in the stratosphere

2011 ◽  
Vol 4 (1) ◽  
pp. 55-66 ◽  
Author(s):  
A. Theuerkauf ◽  
M. Gerding ◽  
F.-J. Lübken
Keyword(s):  
High Reliability ◽  
Sampling Rate ◽  
Atmospheric Physics ◽  
Turbulent Layer ◽  
First Case ◽  
Radiosonde Station ◽  
Wind Measurements ◽  
Scale Turbulence ◽  
Constant Temperature Anemometer ◽  
First Time

Abstract. We have developed a new compact balloon payload called LITOS (Leibniz-Institute Turbulence Observations in the Stratosphere) for high resolution wind turbulence soundings in the stratosphere up to 35 km altitude. The wind measurements are performed using a constant temperature anemometer (CTA) with a vertical resolution of ~2.5 mm, i.e. 2 kHz sampling rate at 5 m/s ascent speed. Thereby, for the first time, it is possible to study the entire turbulence spectrum down to the viscous subrange in the stratosphere. Including telemetry, housekeeping, batteries and recovery unit, the payload weighs less than 5 kg and can be launched from any radiosonde station. Since autumn 2007, LITOS has been successfully launched several times from the Leibniz-Institute of Atmospheric Physics (IAP) in Kühlungsborn, Germany (54° N, 12° E). Two additional soundings were carried out in 2008 and 2009 in Kiruna, Sweden (67° N, 21° E) as part of the BEXUS program (Balloon-borne EXperiments for University Students). We describe here the basic principle of CTA measurements and prove the validity of this method in the stratosphere. A first case study allows a clear distinction between non-turbulent regions and a turbulent layer with a thickness of some tens of meters. Since our measurements cover the transition between the inertial and viscous subrange, energy dissipation rates can be calculated with high reliability.

TRANSPORT CHARACTERISTICS IN c-AXIS La2-xSrxCuO4 (LSCO) SINGLE CRYSTALS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 447-450
Author(s):  
SANG-JAE KIM ◽  
TAKESHI HATANO
Keyword(s):  
Temperature Dependence ◽  
Single Crystals ◽  
Critical Current ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Etching Method ◽  
First Time ◽  
Small Voltage

c-axis micro-bridges of La 2-x Sr x CuO 4 ( LSCO ) single crystals were fabricated by the focused-ion-beam (FIB) etching method. Small rectangular LSCO pieces were fabricated by cutting and grinding single crystals of underdoped LSCO of x=0.09. The size of LSCO single crystals between electrodes was cut to 20×40μm2 in ab-plane by using the FIB etching method. Superconductor-insulator-superconductor (SIS) like-branch structures on I-V curves of the LSCO stacks were observed for the first time. The branch structures exhibited voltage jumps of several tens mV in the range of from 1.7 K to 5 K with temperature dependence. When the temperature is changed from 5 K to 1.7 K , the critical current and the next branch split into a few of small voltage jumps with the intervals of several mV in the range of from 0.1 mV and 2.0 mV .

scholarly journals FABRICATION OF LARGE CONE ANGLE OPTICAL FIBER PROBE BY DYNAMIC CHEMICAL ETCHING METHOD

2001 ◽  
Vol 50 (12) ◽  
pp. 2382
Author(s):  
SUN JIA-LIN ◽  
TIAN GUANG-YAN ◽  
LI QIN ◽  
ZHAO JUN ◽  
GUO JI-HUA ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Chemical Etching ◽  
Cone Angle ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Etching Method ◽  
Large Cone Angle

scholarly journals Operational TBE incidence forecasts for Austria, Germany, and Switzerland 2019-2021

2020 ◽  
Author(s):  
Franz Rubel ◽  
Katharina Brugger
Keyword(s):  
Negative Binomial ◽  
High Reliability ◽  
Virus Transmission ◽  
Negative Binomial Regression ◽  
European Beech ◽  
Transmission Cycle ◽  
Tick Borne Encephalitis ◽  
Tbe Virus ◽  
Binomial Regression ◽  
First Time

In spring 2019, forecasts of the incidence of tick-borne encephalitis (TBE) for the next two years, i.e. 2019 and 2020, were made for the first time. For this purpose, negative binomial regression models with 4-5 predictors were fitted to the time series of annual human TBE incidences from Austria, Germany and Switzerland. The most important predictor for TBE incidences is the fructification index of the European beech (Fagus sylvatica) 2 years prior as a proxi for the intensity of the TBE virus transmission cycle. These forecasts were repeated in spring 2020 after the updated predictors and the confirmed TBE cases for 2019 became available. Forecasting TBE incidences for 2020 and 2021 results in 156±19 and 131±23 TBE cases for Austria, 663±95 and 543±112 TBE cases for Germany as well as 472±56 and 350±62 TBE cases for Switzerland. The newly implemented operational TBE forecasts will be verified every year with confirmed TBE cases. An initial verification for 2019 demonstrates the high reliability of the forecasts.

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