中国科学院机构知识库网格系统: 检索

Detection and analysis of Galileo signal in space anomalies from 2017 to 2018 期刊论文 OAI收割
IET RADAR SONAR AND NAVIGATION, 2020, 卷号: 14, 期号: 11, 页码: 1690-1696
作者: Fan, Lihong; Tu, Rui; Zhang, Rui; Han, Junqiang; Zhang, Pengfei

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distance measurement error analysis satellite navigation aircraft landing guidance radio receivers Galileo signal space anomalies broadcast ephemeris user navigation SIS anomaly advanced receiver autonomous integrity monitoring precise ephemeris SIS error healthy Galileo satellites corresponding detection thresholds satellite SIS anomalies satellite clock error SIS stability time 7 0 hour time 2 5 hour time 50 0 hour time 4 5 hour

Studies on the toxic effects of microcystin-LR on the zebrafish (Danio rerio) under different temperatures 期刊论文 OAI收割
JOURNAL OF APPLIED TOXICOLOGY, 2011, 卷号: 31, 期号: 6, 页码: 561-567
作者: Zhang, Xuezhen; Ji, Wei; Zhang, Huan; Zhang, Wei; Xie, Ping

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microcystin-LR temperature LD50 glutathione S-transferases real-time PCR zebrafish

Embedded system of time uniform based on DSP (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
作者: Li N.; Liu C.-X.; Liu C.-X.; Chen J.; Guo L.-H.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

We introduced a design method of DSP-based System of time uniform which combine the GPS and the Compass to calibrate the time. The system can use UTC (Coordinated Universal Time) of the GPS or the Compass for time base to generate absolute time and different frequency of synchronous signals. We used DSP (Digital Signal Processor) to calculate the satellite information which includes the UTC time. After getting the UCT time information put it into the CPLD (Complex Programmable Logic Device) for correction of time delay and serialization to output. Meanwhile we divided 1PPS (one-pulse-per-second) signal of the GPS and the Compass into 20Hz 50Hz and 800Hz synchronous signal. And we analyzed the precision of time and frequency. To conclude the uncertainty of system absolute time is less than 100ns the uncertainty of system synchronous signals is less than 20ns. This system is easy and flexible for use stable and reliable in performance. 2010 IEEE.

An improved fast parallel SPIHT algorithm and its FPGA implementation (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Future Computer and Communication, ICFCC 2010, May 21, 2010 - May 24, 2010, Wuhan, China
作者: Jin L.-X.; Tao H.-J.; Wu Y.-H.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

In view of the current stringent need to the real-time compression algorithm of the high-speed and high-resolution image such as remote sensing or medical image and so on in this paper No List SPIHT (NLS) algorithm has been improved and a fast parallel SPIHT algorithm is proposed which is suitable to implement with FPGA. It can deal with all bit-planes simultaneously and process in the speed of 4pixels/period so the encoding time is only relative to the image resolution. The experimental results show that the processing capacity can achieve 200MPixels/s when the input clock is 50MHz the system of this paper need 2.29ms to complete lossless compression of a 512x512x8bit image and only requires 1.31ms in the optimal state. The improved algorithm keeps the high SNR unchanged increases the speed greatly and reduces the size of the needed storage space. It can implement lossless or lossy compression and the compression ratio can be controlled. It could be widely used in the field of the high-speed and high-resolution image compression. 2010 IEEE.

A design on a control method of a new type of focal plane shutter (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
Xue L.; Ming L.; Zheng L.-N.; Zhou J.-F.; Zhang H.-W.; Zhang J.-C.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

In order to ensure appropriate exposure time and no exposure while electric charge is transferring after taking a photograph it is necessary to have the shutter mechanism cooperate with CCD for area CCD aerial cameras. The ground object illumination has a wide range which is from 4000Lx to 100000Lx so a shutter which is high efficient and a continuous stepless adjustment are also required. This paper introduces the fundamental principle structural design and control procedure about this new focal plane shutter. Under the control of DSP the velocity of shutter curtain governed by the shutter motor can be not only precisely controlled but also the durability and the reliability are increased. The experiment results have shown that this new shutter has the higher stability of movement long life span with more than 105 operating times a wide range of exposure time from1/ 50s to 1/ 320s(depending on the slit width)and the exposure error is less than 10%. With the CCD gain adjustment the performance of this shutter is fully satisfied with the requirements of area CCD aerial cameras. 2010 IEEE.

Replacement of methane from quartz sand-bearing hydrate with carbon dioxide-in-water emulsion 期刊论文 OAI收割
energy & fuels, 2008, 卷号: 22, 期号: 3, 页码: 1759-1764
作者: Zhou, Xitang; Fan, Shuanshi; Liang, Deqing; Du, Jianwei

收藏 | 浏览/下载：87/10 | 提交时间：2010/09/23

The replacement of CH4 from its hydrate in quartz sand with 90:10, 70:30, and 50:50 (W-CO2:W-H2O) carbon dioxide-in-water (C/W) emulsions and liquid CO2 has been performed in a cell with size of empty set 36 x 200 mm. The above emulsions were formed in a new emulsifier, in which the temperature and pressure were 285.2 K and 30 MPa, respectively, and the emulsions were stable for 7-12 h. The results of replacing showed that 13.1-27.1%, 14.1-25.5%, and 14.6-24.3% of CH4 had been displaced from its hydrate with the above emulsions after 24-96 It of replacement, corresponding to about 1.5 times the CH4 replaced with high-pressure liquid CO2. The results also showed that the replacement rate of CH4 with the above emulsions and liquid CO2 decreased from 0.543, 0.587, 0.608, and 0.348 1/h to 0.083, 0.077, 0.069, and 0.063 1/h with the replacement time increased from 24 to 96 h. It has been indicated by this study that the use of CO2 emulsions is advantageous compared to the use of liquid CO2 in replacing CH4 from its hydrate.

The spectral feature analysis of semiconductor thin disk laser (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Materials and Devices II, November 2, 2007 - November 5, 2007, Wuhan, China
作者: Li J.; Wang L.-J.; Wang L.-J.; Ning Y.-Q.; Li J.

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The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of semiconductor disk laser and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperature. We can see that: with increasing pump power the thermal effects of the gain material becomes seriously and causes the saturation of carrier lifetime so the electron-hole pair created in the absorbtion layer have no enough time to rate to one of the wells and the non-radiative recombination happens in the barrier. When the thermal effects becomes stronger the chip will not lasing. This phenomenon is from the smaller energy offset between barrier and quantum well. We optimize the original structure design and experimental technology. A non-absorbing AlGaAs layer who is transparent to the pumping and laser wavelength is added to confine the carriers in the quantum wells. At the same time a DBR with double reflecting band is induced to improve the absorbing efficiency of the pumping light. The single QW is replaced by the three narrow QWs This three QWs structure can add the quantum state of QW increase the recombination probability of carriers in the QWs and reduce the heat effect. The chemical etch equipment is also improved to control the surface unevenness to be within 50 nm.

Study of microsphere plate photomultiplier tube (EI CONFERENCE) 会议论文 OAI收割
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
作者: Wang X.; Li Y.; Li Y.; Li Y.; Li Y.

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The photomultiplier tube (PMT) that can work in different wavelength is an important detector device in remote sense technology. Microsphere plate using glass beads 50to 70m in diameter sintered together is the core component of the microsphere plate photomultiplier tube It is a novel two-dimension electron multiplier. The electrons gain for a single plate is about 1017 and do not have the phenomenon of ion-feedback. Furthermore the fabrication process is very easy. In this paper much interest was put on the microsphere plate photomultiplier tube. Based on the analyses from the theory and the experiment result we point out the key technology for fabricating PMT is how to obtain glass beads with narrow range in diameter and how to sinter the glass beads with a sufficient pylome. Factors affect the gradating technology and sintering process along with the solution to them is presented. In the last the structure scheme and technological characteristic for fabricating microsphere plate photomultiplier tube were given. The pulse rising-time of MSP-PMT is below 400ps suitable to the detection of high-speed pulse. As easy to be fabricated and has great advantage over MCP multiplier in the ratio of performance to price the microsphere plate photomultiplier tube is a promising dim-light detector.

Fabrication of polysilicon thin film on glass with low-temperature UV-assisted crystallization (EI CONFERENCE) 会议论文 OAI收割
ICO20: Display Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Huang J. Y.; Ling Z. H.; Jing H.; Fu G. Z.; Zhao Y. H.

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The amorphous silicon (a-Si) film was crystallized on glass by a simple method employed ultraviolet at temperatures as low as 400C. The employ of ultraviolet enhanced the crystallization of amorphous silicon. This method is able to uniformly crystallized large-area amorphous silicon films. The polysilicon films crystallized by this way are suitable for the fabrication of thin film transistors on ordinary glass. Crystallization process is performed in a furnace. Amorphous silicon sample is placed on a hot plate and irradiated by a bank of ultraviolet lamps through a diffuser plate to improve the uniformity of light that irradiates the sample. Raman microscopy is used for analyzing the qualities of UV-assisted crystallized silicon films. By measuring the Raman spectra the effects of anneal temperature and process time on the crystallizing behavior crystallinity and grain size of the processed films were obtained. There has a threshold temperature for crystallization of amorphous silicon film in the presence of ultraviolet irradiation with certain intensity i.e. by ultraviolet irradiation with certain intensity only when the temperature is up to the threshold temperature the crystallization can be triggered. The threshold temperature is 400C when the intensity of ultraviolet irradiation is 1mW/cm2. Above threshold temperature the increase of anneal temperature increased the rate of crystallization. Crystallinity and grain size extracted from Raman spectra of samples increase with the extending of process time at certain temperature. Crystallization of amorphous silicon film with thickness of 50nm completed within 6 hours at 400C irradiated by ultraviolet with intensity of 2mW/cm2.

Lossless wavelet compression on medical image (EI CONFERENCE) 会议论文 OAI收割
4th International Conference on Photonics and Imaging in Biology and Medicine, September 3, 2005 - September 6, 2005, Tianjin, China
作者: Liu H.; Liu H.; Liu H.

收藏 | 浏览/下载：59/0 | 提交时间：2013/03/25

An increasing number of medical imagery is created directly in digital form. Such as Clinical image Archiving and Communication Systems (PACS). as well as telemedicine networks require the storage and transmission of this huge amount of medical image data. Efficient compression of these data is crucial. Several lossless and lossy techniques for the compression of the data have been proposed. Lossless techniques allow exact reconstruction of the original imagery while lossy techniques aim to achieve high compression ratios by allowing some acceptable degradation in the image. Lossless compression does not degrade the image thus facilitating accurate diagnosis of course at the expense of higher bit rates i.e. lower compression ratios. Various methods both for lossy (irreversible) and lossless (reversible) image compression are proposed in the literature. The recent advances in the lossy compression techniques include different methods such as vector quantization wavelet coding neural networks and fractal coding. Although these methods can achieve high compression ratios (of the order 50:1 or even more) they do not allow reconstructing exactly the original version of the input data. Lossless compression techniques permit the perfect reconstruction of the original image but the achievable compression ratios are only of the order 2:1 up to 4:1. In our paper we use a kind of lifting scheme to generate truly loss-less non-linear integer-to-integer wavelet transforms. At the same time we exploit the coding algorithm producing an embedded code has the property that the bits in the bit stream are generated in order of importance so that all the low rate codes are included at the beginning of the bit stream. Typically the encoding process stops when the target bit rate is met. Similarly the decoder can interrupt the decoding process at any point in the bil stream and still reconstruct the image. Therefore a compression scheme generating an embedded code can start sending over the network the coarser version of the image first and continues with the progressive transmission of the refinement details. Experimental results show that our method can get a perfect performance in compression ratio and reconstructive image.