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Relation Between the Evolution of Earthquake Precursory Field and the Nonlinear Concentration of Energy

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Earthquake Research in china 1998年第3期12卷 77-85页

作者： Zheng Ximing, Xiao Jiaxin, and Lin JiatiSeismological Bureau of tianjin Municipality, tianjin 300201, china tianjin University, tianjin 300072, china

The evolutional process of precursory fields for the Tangshan earthquake with MS7.8 and the Datong earthquake with MS6.1 was simulated by using the process of regional energy concentration for the nonlinear vibration in inhomogeneous media. The results show that the various precursory features observed during the seismogenic process would be related with the nonlinear concentration of energy in the crust.

关键词： Seismic precursor Nonlinear evolution Energy concentration Tangshan earthquake Datong earthquake.

维普期刊数据库

Computer Three-dimensional reproduction technology of buildings in Digital City

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微计算机信息 2005年第8期 22-23+30页

作者： Liu,Hao Dai,Jufeng Liu,Zhaoping (Dept. of Computers, Shandong Institute of Architecture and Engineering,Jinan,china, 250014)(School of Electronic Information Engineering, tianjin University,tianjin, china, 300072)

In real-life of today, computer show dynamic and mutual for buildings is often necessary using virtual reality. Establishing virtual reality has a large choice of methods, but the differences of effects are big. A bes... 详细信息

关键词： Virtual reality multi-dimension material three dimension Boolean operation

THE EFFECT OF VIBRATION ON A NEW FRESH AIR HEAT EXCHANGER

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THE EFFECT OF VIBRATION ON A NEW FRESH AIR HEAT EXCHANGER

2007世界太阳能大会：太阳能与人类居住

作者： Yiping Wang School of Chemical Engineering and Technology tianjin University china tianjin 300072 china Na Feng School of Chemical Engineering and Technology tianjin University china tianjin 300072 china Li Zhu School of Architecture tianjin University china tianjin 300072 china Jianguo Kong tianjin Cuipinglu Science Park tianjin 301908 china

＜正＞With the increasing of building energy consumption,the envelope of the buildings is becoming tighter to save *** this really causes the indoor air quality （IAQ） a problem for less infiltration,and as a result,people living in such buildings are showing a series of *** elevate the indoor air quality （IAQ）,lots of fresh air should be taken indoor,thus will increase the energy consumption *** air exchanger which is devoted to indoor air quality （IAQ） and save energy at the same time is *** researches proved that recycling the indoor air’s energy generally can save 70-80% energy,and the economic value is great. In this paper,a new type of fresh air exchanger using plastic membrane as heat exchanger is presented,it weights light while costs *** the velocity of air in the air-air exchanger is low,its flow belongs to the range of laminar flow,and thermal resistance mostly relies on boundary *** are carried out to research vibration’s effect on the boundary *** of experiments present that the heat exchanged through plastic membrane can be enhanced by the vibration resulted from fluid *** is proved that this type of fresh air heat exchanger can improve the ratio of system performance and cost,and enhance the recovery percentage and have a long-term market outlook.

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MEMORY EFFICIENT IMAGE COMPRESSING USING LIFTING SCHEME

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MEMORY EFFICIENT IMAGE COMPRESSING USING LIFTING SCHEME

第七届国际信号处理会议

作者： CHEN Hongxin LIU Zhengguang ZHANG Hongwei (Institute of Automation tianjin University tianjin china 300072)

The transforming of mapping image data from RGB to YUV color space serves to reduce the correlation between components and it is suitable for human visual system. The line-based wavelet transform c

关键词： wavelet transform image compression lifting scheme JPEG2000

Effects of Co2O3 on the Dielectric Properties of Mg2TiO4-Mg2SiO4 Microwave Ceramics

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Effects of Co2O3 on the Dielectric Properties of Mg2TiO4-Mg2...

The 3～〔rd〕International Conference on High-Performance Ceramics(CICC-3)（1）

作者： Lingxia Li, Xiaodong Sun and Xiawan Wu School of Electronic Information Engineering, tianjin University, tianjin, china 300072

Effect of CoO on microstructure and dielectric properties of MgTiO-MgSiO microwave ceramic with low permittivity and high Q value was studied. Co2O3 acts and results in decreasing of the sintering temperature and densification of the ceramic material. As a result, the dielectric loss decreases and quality factor Q increases. Mg2+ is replaced partially with Co2+ in Mg2TiO4 to form (Mg,Co)2TiO4. It is demonstrated that the system with 2.4 wt% Co2O3 possesses better dielectric properties.

关键词： Cobalt oxide Microwave ceramic Quality factor

Facial Expression Recognition Based on PCA Reconstruction

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Facial Expression Recognition Based on PCA Reconstruction

2011高等职业教育电子信息类专业学术暨教学研讨会

作者： Zhenjin CHENG,Zheng ZHAO,Han SUN College of Computer Science and Technology,tianjin University,tianjin,china,300072

The article proposed a new way of facial expression recognition by reconstructing the PCA *** the training set into 7 parts by expression,and get the Orthonormal Basis of each subset expression by PCA *** make projection with the original image on each of the Orthonormal Basis,rebuilt the projection coordinate and recognize the expression by the combination of D-value summation and similarity ***,we get the final result by comparing the similarity between the original and reconstruction image.

关键词： expression recognition PCA image reconstruction D-value summation similarity

Dual-band Piezoelectric Bulk-Acoustic-Wave Coupled Resonator Filter with Unified Input

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Dual-band Piezoelectric Bulk-Acoustic-Wave Coupled Resonator...

2011年全国压电和声波理论及器件应用研讨会

作者： Chong Zhou,Wei Pang and Hao Zhang College of Precision Instrument and Opto-electronics Engineering,tianjin University 92 Weijin Road,Nankai District,tianjin,china 300072

＜正＞A typical radio-frequency（RF） front-end of a GSM/DCS mobile handset consists of two transmitter（Tx） ports and two receiver（Rx） ports which are connected to an antenna through a single-pole-four-throw（SP4T） RF *** the Rx path,two band-pass RF filters work together with the RF switch to select the GSM900 and DCS 1800 signals received by the antenna,and the filters are required to have the ability to perform single-ended input to differential output conversion because the input of subsequent low noise amplifiers（LNAs） are often differential for noise reduction and linearity improvement. In order to get rid of the RF switch to reduce the complexity of the front-end,a GSM/DCS dual-band filter with a unified input is *** proposed dual-band filter is based on piezoelectric bulk-acoustic-wave （BAW） coupled resonator filter（CRF） technology.A CRF consists of two BAW resonators which are vertically stacked and isolated by a coupling layer,making it possible to provide single-ended to differential conversion and impedance *** devices present numerous advantages such as high frequency operation,high quality factor（Q）,good linearity,and extremely small die size,which are believed to be good alternatives of traditional surface acoustic wave（SAW） filters in certain applications. The design methodologies of the GSM/DCS dual-band filter base on BAW CRF technology are presented in this paper.A couple of novel approaches to deal with the coupling layer capacitance in the CRF structure to improve the filter roll-off performance as well as the amplitude and phase imbalances are *** simulation and layout results of the GSM900 and DCS 1800 dual-band filter clearly demonstrate the filter alone（without a RF switch needed） could nicely perform the selection of GSM900 and DCS 1800 signals with excellent characteristics such as single-ended to balanced conversion,impedance transformation and significant die size reduction.

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使用马丁内兹展宽器的啁啾脉冲放大器特性研究

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物理学报 2003年第3期52卷 581-586页

作者：宋晏蓉张志刚王清月天津大学精密仪器与光电子工程学院光电子信息技术科学国家教育部重点实验室天津300072

导出了使用马丁内兹展宽器的啁啾脉冲放大 (CPA)系统的相位解析表达式 ,用此公式讨论了展宽器中各参数对系统的影响 ,并用此方法优化了实际的CPA系统 .

关键词：特性马丁内兹展宽器啁啾脉冲放大系统相位修正因子优化 CPA

维普期刊数据库

Study on Excitation Frequency of Longitudinal and Torsional Guided Waves

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Study on Excitation Frequency of Longitudinal and Torsional ...

2009中国控制与决策会议

作者： Sun Li-ying~(1,2) 1.Department of Energy and Mechanics Engineering,,tianjin Institute of Urban Construction,tianjin,china,300384 2.State Key Laboratory on Precise Measuring and Testing Technique and Instrument,tianjin University,tianjin,china,300072

＜正＞Guided ultrasonic wave is a new non-destructive pipe inspection method for rapid,long distance *** can be used to inspect pipes,especially those buried underground or difficult to access using other conventional NDT *** this paper,the excitation frequency of two most commonly used ultrasonic guided waves,longitudinal wave and torsional wave were researched,and the lower and upper frequency limit were discussed in ***, factor that may affect the selection of experimental frequency was studied and optimum frequency of guided wave for a carbon steel experimental pipe was selected.

关键词： Frequency selection longitudinal wave torsional wave rapid pipe inspection