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High finesse hollow-core photonic bandgap fiber (HC-PBF) resonating Fabry–Perot gas cells are presented. These gas cells are made with a piece of HC-PBF sandwiched by two single mode fibers with mirrored ends. A HC-PBF cavity made with 6.75-cm-long HC-1550-06 fiber achieved a cavity finesse of 128, corresponding to an effective optical path length of ∼5.5 m. Experiment with a 9.4-cm-long Fabry–Perot...
We have developed a radar-based microwave breast imaging system for clinical use. The system consists of a multi-static virtual array with two ultra-wideband horn antennas controlled by mechanical rotation. A conformal breast image is reconstructed by applying the weighted delay-and-sum algorithm. As the Phase I of our aimed clinical trial, we have carried out multiple tests for 11 women aged from...
A multiplicative regularization scheme with edge-preserving characteristics is applied to the inversion of electrical impedance tomography (EIT) data. This scheme employs a multiplicative cost function of a weighted L2-norm regularization function and the data misfit function. It avoids the use of a weighting factor when the regularization term is added to the cost function and allows an adaptive...
Aiming at the problem of harsh operating condition of the space manipulator and not being able to support great collision Momentum, this paper proposes a new concept and technical method, called soft-contact technology. According to this, the paper designs a space manipulator joint configuration based on bionics and carries out its rigid-flexible composite characteristic simulation. Simulation results...
A single-layer dual-band metal-only reflectarray antenna (MORA) is designed for the first time. It is capable to achieve differently-oriented pencil beams with the same linear polarization at X and Ku bands. The slot-type Phoenix elements are used with multi-parameter sweeping strategy to simultaneously provide sufficient phase shift coverage at the two design frequencies. At the reflectarray system...
In this paper, the working modes of 1-bit reflectarray cell with one p-i-n diode at W-band are discussed in detail. The structure of the unit cell and the model of the p-i-n diode at W-band is presented first. The modes of the unit cell at ON/OFF state of p-i-n diode are described using the resonance cavity theory. A positive phase shift of 180° and a negative phase shift of 180° can be achieved in...
A new structure of 60-GHz substrate integrated waveguide Butler matrix based on silicon dioxide is proposed. Straight delay lines are employed to realize the required 45° and 0° phase shifters in the Butler matrix, which makes the Butler matrix more compact in width. The simulations show that the insertion losses are below −2.7 dB and the reflections and isolations are lower than −15 dB from 58 GHz...
A novel 2-bit reconfigurable reflectarray element for both linear and circular polarizations is proposed. The element structure is a microstrip patch backed by a slot-loaded plane. Combining the current reversal mechanism and tunable resonance approach, five PIN diodes are integrated on the slots to control the current direction and effective slot length, which lead to a tunable phase shift. The simulated...
There is a huge demand to apply classification in medical analysis. A traditional classifier requires having training samples from each class. However, in reality, it is possible that the testing set may include classes that are not in the training set. This inevitably causes an issue: data from a undefined class will be assigned to a predefined classes. To tackle this, we propose a semi-supervised...
This paper presents a passive RFID patch antenna for wireless tilt sensing. The shorted patch antenna has a compact structure and low profile, with an overall size of 40 mm × 61.4 mm × 1.57 mm. Loaded with four mercury switches, it can detect five tilt states from two axes according to the resonant frequency of the sensor.
The scattering properties of metascreens are characterized based on Babinet's principle and generalized sheet transition conditions for metafilms. Through this method, the reflection and transmission coefficients of metascreens could be computed analytically, under arbitrary incident angles and polarizations, once the surface susceptibilities of corresponding complementary metafilms have been extracted...
In order to improve the accuracy of wind speed prediction, the paper proposed a brand new prediction model, called the nonlinear least squares autoregressive moving average model, which based on the wavelet decomposition and reconstruction. Firstly, this model introduces the wavelet transform, which decomposes the original non-stationary wind speed sequence into a relatively stable sequence; Then...
The design and simulations of a Ku-band 1-bit reconfigurable transmitarray is presented. The proposed element consists of two orthogonal H-shaped slots and a coupling microstrip transmission line. By controlling the two PIN diodes integrated on the transmission line, opposite ends of the receiving H-shaped slot are excited, thus achieving 1-bit quantized phase with 180° phase difference. The simulated...
This work aims to build pixel-to-pixel correspondences between images from the same visual class but with different geometries and visual similarities. This task is particularly challenging because (i) their visual content is similar only on the high-level structure, and (ii) background clutters keep bringing in noises. To address these problems, this paper proposes an object-aware method to estimate...
The experiments and results of these calibation campaigns in the frame of APMP from 2014 to 2016 have been reported and the experiment setups and the corresponding delay measurements have been discussed, and the uncertainty has been evaluated for the campaigns.
China's Grain for Green Programme (GGP) is the largest ecological restoration programme ever implemented in a developing country, but the ecological effectiveness in its whole implementation region still remain uncertain. Based on the trend analysis of dynamics in ecosystem structure and service, we assessed the ecological effects before and after the implementation of the GGP in 1990–2010 by developing...
Debris-covered glaciers are an important component of glacier systems on Earth. In this paper, using Landsat Thematic Mapper (TM) images, MOD05 products and digital elevation model (DEM) as data source. Land surface reflectance, land surface temperature (LST) and topographic slope are retrieved from optical bands, thermal band and DEM, respectively. A rule set that combines optical reflectance, LST...
Because the inconsistencies always could be found in the comparison, Cox recommended Monte Carlo Method (MCM) to solve this problem and determine the key comparison reference value (KCRV). In the paper, we introduced the MCM in analyzing APMP.M.M-K1 international measurement comparisons. This method, which is based on statistics estimation method, can directly give the degrees of equivalence(DoE)...
In order to solve the problem of harsh operating condition of the space manipulator, and the problem of not being able to afford great collision Momentum, this paper proposes a new technical method, namely soft-contact technology. According to the proposed method, the dynamic model of space flexible manipulator is built up based on Kane's equations. Then this paper makes a comparison simulation between...
Nowadays a great amount of space debris threat the safety of space activities, so the space debris removal becomes a hot research field. In particular, on the base of space mechanical arm technology, using mechanical arm to remove space debris proves feasible in the implementation. Traditional space mechanical arms are rigid arms, and in consideration of the uncontrolled momentum of rigid arm, this...
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