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Search Results: 1 - 10 of 120232 matches for " Jianqi Wang "
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Wireless Bioradar Sensor Networks for Speech Detection and Communication  [PDF]
Ying Tian, Sheng Li, Jianqi Wang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.55B008
Abstract: Wireless multimedia sensor networks (WMSN) are emerging to serve for the collection of acoustic and image information. In the WMSN, the microphone is usually employed to function as sensor nodes for the acquisition of acoustic data. However, those microphone sensors are needed to be placed close with sound source and cannot detect sound signal through certain obstacles. To overcome the shortcomings of microphone sensor, we develop a new type of bioradar sensor to achieve non-contact speech detection and investigate theoretically the mechanism of bioradar for speech detection. Results show that the system can successfully detect speech at some distance and even through non-metallic objects with certain thickness. In addition, in order to suppress the noise and improve the quality of the detected speech, we use spectral subtraction and Wiener filtering algorithm respectively to enhance the bioradar speech and evaluate the performance of the two methods using spectrogram.
Comparative study of the effect of Cu2O and MoO3 on flame retardance and smoke emission of PVC by Cone and TGA
Bin Li,Jianqi Wang
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883079
Abstract: Cuprous and molybdic oxides exhibit extremely effectiveness in smoke suppression for PVC. However, few are the data reported concerning flame retardance and smoke emission of PVC taken from Cone calorimetry relative to the conventional thermal analysis technique. Abundant data from Cone calorimetry have been acquired. Data analysis was achieved through the study of MLR, HRR, SEA tested at irradiance of 25 kWm 2. The understandable flame retardance of PvC/Cu2O and pVC/MoO3 relative to pure PVC has been rationalized by their lowered heat release rates and enhanced char residues. The difference in smoke reduction between these two oxides consists in the time scale. As clearly seen under air atmosphere both oxides exert themselves to the afterglow which has been recognized as a dangerous source, in particular in the full-scale fire situation.
Relationship between Arctic Oscillation and Pacific Decadal Oscillation on decadal timescale
Jianqi Sun,Huijun Wang
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-004-0221-3
Abstract: The relationship between the Pacific Decadal Oscillation (PDO) and the Arctic Oscillation (AO) on decadal timescale in the extended winter (November–March) is investigated in this study. The results indicate that AO plays an important role in the low frequency variability of PDO. When AO leads PDO by 7–8 years, the lagging correlation between them becomes the strongest with correlation coefficient 0.77. The leading decadal variability of AO pro-vides a valuably precursory signal for predicting the variability of PDO. The results of regression and lagging correlation reveal the possible mechanism for the AO-PDO coupling: A strong AO would lead to an enhanced Aleutian Low that is linked to PDO by ocean-atmosphere interaction in the North Pacific, and vice versa.
Variability of Northeast China river break-up date

Huijun Wang,Jianqi Sun,

大气科学进展 , 2009,
Abstract: This paper investigates the variability of the break-up dates of the rivers in Northeast China from their icebound states for the period of 1957--2005 and explores some potential explanatory mechanisms. Results show that the break-up of the two major rivers (the Heilongjiang River and Songhuajiang River) was about four days earlier, and their freeze-up was about 4--7 days delayed, during 1989--2005 as compared to 1971--1987. This interdecadal variation is evidently associated with the warming trend over the past 50 years. In addition, the break-up and freeze-up dates have large interannual variability, with a standard deviation of about 10--15 days. The break-up date is primarily determined by the January--February--March mean surface air temperature over the Siberian-Northeast China region via changes in the melting rate, ice thickness, and snow cover over the ice cover. The interannual variability of the break-up date is also significantly connected with the Northern Annular Mode (NAM), with a correlation coefficient of 0.35--0.55 based on the data from four stations along the two rivers. This relationship is attributed to the fact that the NAM can modulate the East Asian winter monsoon circulation and Siberian-Northeast China surface air temperature in January--February--March.
Magnetostratigraphic dating of mammalian fossils in Junggar Basin, northwest China
Rui Zhang,LePing Yue,JianQi Wang
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0205-1
Abstract: The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented, based on rock magnetic experiments and magnetostratigraphic investigations of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization, and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS). Furthermore, the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary, and the Suosuoquan fauna layer is just above the Neocene onset. Therefore, the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma, respectively.
The northern annular mode: More zonal symmetric than the southern annular mode
HuiJun Wang,JianQi Sun,JingZhi Su
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0114-y
Abstract: Fan (2007) recently documented the zonal asymmetry of the Antarctic oscillation (AAO) in the austral winter. In this research, the zonal asymmetry of the northern annular mode, or the Arctic oscillation (AO), in the interannual variability is studied for the boreal winter. It is shown that there is zonal asymmetry of the AO as well, similar to the case of the Antarctic oscillation (AAO). However, the zonal asymmetry of the AO is considerably weaker than that of the AAO. This is far beyond the speculation, since the zonal asymmetry of the geography is larger in the Northern Hemisphere than the Southern Hemisphere. The Western and Eastern Hemispheres portions of the AO are correlated at 0.54 for 1959–1998, comparing with 0.23 for the case of the AAO. The authors also discussed the physical reason for this inter-hemispheric difference, and partly attributed it to the El Ni o and Southern Oscillation (ENSO) cycle which may be represented by the SO index. It is indicated that the SO associated sea-level pressure (SLP) patterns are more zonal symmetric in the high latitudes of the Northern Hemisphere than the Southern Hemisphere.
The northern annular mode: More zonal symmetric than the southern annular mode
The northern annular mode:More zonal symmetric than the southern annular mode

HuiJun Wang,JianQi Sun,JingZhi Su,

科学通报(英文版) , 2008,
Abstract: Fan (2007) recently documented the zonal asymmetry of the Antarctic oscillation (AAO) in the austral winter. In this research, the zonal asymmetry of the northern annular mode, or the Arctic oscillation (AO), in the interannual variability is studied for the boreal winter. It is shown that there is zonal asymmetry of the AO as well, similar to the case of the Antarctic oscillation (AAO). However, the zonal asymmetry of the AO is considerably weaker than that of the AAO. This is far beyond the speculation, since the zonal asymmetry of the geography is larger in the Northern Hemisphere than the Southern Hemisphere. The Western and Eastern Hemispheres portions of the AO are correlated at 0.54 for 1959–1998, comparing with 0.23 for the case of the AAO. The authors also discussed the physical reason for this inter-hemispheric difference, and partly attributed it to the El Ni o and Southern Oscillation (ENSO) cycle which may be represented by the SO index. It is indicated that the SO associated sea-level pressure (SLP) patterns are more zonal symmetric in the high latitudes of the Northern Hemisphere than the Southern Hemisphere.
Interference-Aware Scheduling for Connectivity in MIMO Ad Hoc Multicast Networks
Feng Jiang,Jianqi Wang,A. Lee Swindlehurst
Mathematics , 2012,
Abstract: We consider a multicast scenario involving an ad hoc network of co-channel MIMO nodes in which a source node attempts to share a streaming message with all nodes in the network via some pre-defined multi-hop routing tree. The message is assumed to be broken down into packets, and the transmission is conducted over multiple frames. Each frame is divided into time slots, and each link in the routing tree is assigned one time slot in which to transmit its current packet. We present an algorithm for determining the number of time slots and the scheduling of the links in these time slots in order to optimize the connectivity of the network, which we define to be the probability that all links can achieve the required throughput. In addition to time multiplexing, the MIMO nodes also employ beamforming to manage interference when links are simultaneously active, and the beamformers are designed with the maximum connectivity metric in mind. The effects of outdated channel state information (CSI) are taken into account in both the scheduling and the beamforming designs. We also derive bounds on the network connectivity and sum transmit power in order to illustrate the impact of interference on network performance. Our simulation results demonstrate that the choice of the number of time slots is critical in optimizing network performance, and illustrate the significant advantage provided by multiple antennas in improving network connectivity.
Magnetostratigraphic dating of mammalian fossils in Junggar Basin, northwest China
ZHANG Rui,YUE LePing,WANG JianQi,
ZHANG
,Rui,YUE,LePing,WANG,JianQi

科学通报(英文版) , 2007,
Abstract: The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented,based on rock magnetic experiments and magnetostratigraphic investiga-tions of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization,and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS). Furthermore,the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary,and the Suosuoquan fauna layer is just above the Neocene onset. Therefore,the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma,respectively.
A coaxial-slot antenna for invasive microwave hyperthermia therapy  [PDF]
Teng Jiao, Hua Wang, Yang Zhang, Xiao Yu, Huijun Xue, Hao Lv, Xijing Jing, Hua Zhan, Jianqi Wang
Journal of Biomedical Science and Engineering (JBiSE) , 2012, DOI: 10.4236/jbise.2012.54026
Abstract: When the technique of invasive microwave hyperthermia is applied to cancer treating, the distribution of microwave thermal field and the effect of the therapy are determined by the type of microwave radiative antenna. The thermal field of biological tissue produced by microwave radiative antenna is investigated in this paper. The distribution of thermal field and specific absorption rate (SAR) of invasive coaxial-slot antenna in the frequency of 2450 MHz are obtained by the technique of finite element analysis. According to the experiment of heating the ex vivo pork liver by this kind of antenna, the result concordant with the theory is obtained. Therefore, it is suggested that this research could be a reference for clinical therapy and operation scheme.
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