Studies show that the Tianshan orogenic belt was built in the late stage of the Paleozoic, as evidenced by the Permian red molasses and foreland basins, which are distributed in parallel with the Tianshan belt, indica...Studies show that the Tianshan orogenic belt was built in the late stage of the Paleozoic, as evidenced by the Permian red molasses and foreland basins, which are distributed in parallel with the Tianshan belt, indicating that an intense folding and uplifting event took place. During the Triassic, this orogenic belt was strongly eroded, and basins were further developed. Starting from the Jurassic, a within-plate regional extension occurred, forming a series of Jurassic-Paleogene extensional basins in the peneplaned Tianshan region. Since the Neogene, a collision event between the Indian and the Eurasian plates that took place on the southern side of the Tianshan belt has caused a strong intra-continental orogeny, which is characterized by thrusting and folding. Extremely thick coarse conglomerate and sandy conglomerate of the Xiyu Formation of Neogene System were accumulated unconformably on the Tianshan piedmont. Studies have revealed that the strong compression caused by the Indian-Eurasian collision had a profound influence over the orogenic belt in the hinterland, and MesozoiC-Cenozoic brittle deformed structures superposed on the ductile deformed Paleozoic rocks. The Mesozoic extensional basins were converted into Cenozoic compressional basins. The deformation in the basins is featured by step thrusts and fault-related folds. Statistics of joints show that the principal compressive stress since the Neogene is in a N-S direction. Meanwhile, owing to the underthrusting of the basin toward the orogenic belt, the Paleozoic strata were thrust on the Meso-Cenozoic rocks as tectonic slices, revealing distinct kinematic features in different geologic units. The basin-range coupling zones are characterized by intensive compression, folding and thrusting, accompanied by local sub-E-W-trending strike-slip faults. In the Tianshan region, Cenozoic thrusting is the most common basin-range coupling mode. The folding and faulting of Mesozoic sedimentary rocks, spontaneous combustion of Jurassic coal layers and formation of sintered rocks, the Cenozoic earthquakes and active faulting, and the unique mosaic pattern of basin-range framework of Xinjiang are all products of tectonism since the Neogene.展开更多
Different scales of structural data reveal a complex deformation history of ultrahigh- pressure （UHP） rocks exposed in the Weihai-Rongcbeng area, NE Sulu （northern Jiangsu-eastern Shandong）, eastern China. Excludi...Different scales of structural data reveal a complex deformation history of ultrahigh- pressure （UHP） rocks exposed in the Weihai-Rongcbeng area, NE Sulu （northern Jiangsu-eastern Shandong）, eastern China. Excluding pre-UHP deformations, at least five major sequential deformational stages （D1-Ds） are recognized. The first deformation （DO produced a weak foliation and lineation in massive eclogites. The foliated eclogite with a dominant foliation containing a stretching and mineral lineation was developed during the I）2 deformation. Both the D1 and D2 deformations occurred under UHP metamorphic conditions, and are well preserved in the eclogite bodies. D3 structures which developed shortly after the formation of granulite/amphibolite facies symplectites are characterized by imbricated associations marked by a regional, steeply dipping foliation, compositional layering, eclogite boudinage, isoclinal folds and reverse ductile shear zones. The D3 deformation was accompanied by decompressional partial melting. A regional, gently dipping amphibolite facies foliation and stretching lineation, low-angle detachments, and dome- and arc-shaped structures formed during the D4 deformation stage dominate to some degree the map pattern of the Weihai-Rongcbeng UHP domain. The last stage of deformation （Ds） gave rise to the final exhumation of the UHP rocks. Ds is characterized by development of brittle-dominated high-angle faulting associated with emplacement of large volmnes of undeformed granite plutons and dykes dated at 134-100 Ma. The deformational and metamorphic sequence followed by the UHP rocks in the Weihai-Rongcheng area is similar to that studied in the entire Dabie-Sulu UHP and HP metamorphic belts from microscopic to mapping scale. Based on structural data, combined with available petrographic, metamorphic and geochronological data, a speculative tectonic evolutionary model for the Dabie-Sulu UHP and IIP belts is proposed, involving continental subduction/collision between the Sino-Korean and Yangtze cratons and subsequent polyphase exhumation histories of the UHP and IIP metamorphic rocks.展开更多
The modelling, design and implementation of a high-speed programmable polyphase finite impulse response (FIR) filter with field programmable gate array (FPGA) technology are described. This FIR filter can run automati...The modelling, design and implementation of a high-speed programmable polyphase finite impulse response (FIR) filter with field programmable gate array (FPGA) technology are described. This FIR filter can run automatically according to the programmable configuration word including symmetry/asymmetry, odd/even taps, from 32 taps up to 256 taps. The filter with 12 bit signal and 12 bit coefficient word-length has been realized on a Xilinx VirtexⅡ-v1500 device and operates at the maximum sampling frequency of (160 MHz.)展开更多
In this paper, we describe resourceefficient hardware architectures for softwaredefined radio （SDR） frontends. These architectures are made efficient by using a polyphase channelizer that performs arbitrary sample r...In this paper, we describe resourceefficient hardware architectures for softwaredefined radio （SDR） frontends. These architectures are made efficient by using a polyphase channelizer that performs arbitrary sample rate changes, frequency selection, and bandwidth control. We discuss area, time, and power optimization for field programmable gate array （FPGA） based architectures in an Mpath polyphase filter bank with modified Npath polyphase filter. Such systems allow resampling by arbitrary ratios while simultaneously performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. A nonmaximally decimated polyphase filter bank, where the number of data loads is not equal to the number of M subfilters, processes M subfilters in a time period that is either less than or greater than the Mdataload ＇ s time period. We present a loadprocess architecture （LPA） and a runtime architecture （RA） （based on serial polyphase structure） which have different scheduling. In LPA, Nsubfilters are loaded, and then M subfilters are processed at a clock rate that is a multiple of the input data rate. This is necessary to meet the output time constraint of the down-sampled data. In RA, Msubfilters processes are efficiently scheduled within Ndataload time while simultaneously loading N subfilters. This requires reduced clock rates compared with LPA, and potentially less power is consumed. A polyphase filter bank that uses different resampling factors for maximally decimated, underdecimated, overdecimated, and combined upand downsampled scenarios is used as a case study, and an analysis of area, time, and power for their FPGA architectures is given. For resourceoptimized SDR frontends, RA is superior for reducing operating clock rates and dynamic power consumption. RA is also superior for reducing area resources, except when indices are prestored in LUTs.展开更多
This paper presents efficient processing engines for software-defined radio （SDR） front-ends. These engines, based on a polyphase channelizer, perform arbitrary sample-rate changes, frequency selection, and bandwidt...This paper presents efficient processing engines for software-defined radio （SDR） front-ends. These engines, based on a polyphase channelizer, perform arbitrary sample-rate changes, frequency selection, and bandwidth control. This paper presents an M-path polyphase filter bank based on a modified N-path polyphase filter. Such a system allows resampling by arbitrary ratios while performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. This resampling technique is based on sliding cyclic data load interacting with cyclic-shifted coefficients. A non-maximally-decimated polyphase filterbank （where the number of data loads is not equal to the number of M subfilters） processes M subfilters in a time period that is less than or greater than the M data loads. A polyphase filter bank with five different resampling modes is used as a case study for embedded resamp/ing in SDR front-ends. These modes are （i） maximally decimated, （ii） Under-decimated, （iii） over-decimated, and combined up- and down-sampling with （iv） single stride length, and （v） multiple stride lengths. These modes can be used to obtain any required rational sampling rate change in an SDR front-end based on a polyphase channelizer. They can also be used for translation to and from arbitrary center frequencies that are unrelated to the output sample rates.展开更多
Rheological properties of polyphase rocks play an important role in the dynamics of the lithosphere and asthenosphere. However, such fundamental issues have not been well resolved. A theoretical analysis has been made...Rheological properties of polyphase rocks play an important role in the dynamics of the lithosphere and asthenosphere. However, such fundamental issues have not been well resolved. A theoretical analysis has been made to develop expressions for the flow laws of polyphase rocks in terms of the volume fractions and flow laws of their constituent phases. The flow strengths predicted by the proposed model for common crustal and upper mantle rocks such as granite, diorite, diabase and lherzolite, and for synthetic two phase composites such as forsterite enstatite and water ice ammonia dehydrate aggregates are in good agreement with previously determined experimental values. The proposed theoretical model allows one to calculate, to the first approximation, the flow laws of a large number of polyphase rocks at geologic conditions based on the experimentally determined flow laws of a relatively small number of monomineralic aggregates.展开更多
A novel software tool for optimization and synthesis of RF CMOS polyhase filters(PPFs),PPFOPTIMA,is developed.In the optimization engine,genetic algorithm is adopted to avoid local optima.Experiments on PPFOPTIMA demo...A novel software tool for optimization and synthesis of RF CMOS polyhase filters(PPFs),PPFOPTIMA,is developed.In the optimization engine,genetic algorithm is adopted to avoid local optima.Experiments on PPFOPTIMA demonstrate that it is an efficient design aid for design and optimization of RF CMOS PPFs.展开更多
The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of ...The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of a resolver is approached. And a polyphase multipole resolver is developed in the brushless DC torque motor. Finally, the experimental results are presented to illustrate the improvement of ripple torque in the brushless DC torque motor with the polyphase multipole resolver.展开更多
An efficient single-carrier symbol synchronization method is proposed in this paper,which can work under a very low oversampling rate.This method is based on the frequency aliasing squared timing recovery assisted by ...An efficient single-carrier symbol synchronization method is proposed in this paper,which can work under a very low oversampling rate.This method is based on the frequency aliasing squared timing recovery assisted by pilot symbols and time domain filter.With frequency aliasing squared timing recovery with pilots,it is accessible to estimate timing error under oversampling rate less than 2.The time domain filter simultaneously performs matched-filtering and arbitrary interpolation.Because of pilot assisting,timing error estimation can be free from alias and self noise,so our method has good performance.Compared with traditional time-domain methods requiring oversampling rate above 2,this method can be adapted to any rational oversampling rate including less than 2.Moreover,compared with symbol synchronization in frequency domain which can operate under low oversampling rate,our method saves the complicated operation of conversion between time domain and frequency domain.By low oversampling rate and resource saving filter,this method is suitable for ultra-high-speed communication systems under resource-restricted hardware.The paper carries on the simulation and realization under 64QAM system.The simulation result shows that the loss is very low(less than 0.5 dB),and the real-time implementation on field programmable gate array(FPGA)also works fine.展开更多
It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear...It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear phase,however,can be also obtained with the IIRfilter by making use of a technique without increasing the complexity.Based on a certain numberof attenuation zeros in the pass band,a new approach is developed for the design of polyphasewave digital filters with exact magnitude responses and Chebyshev approximation of the desiredphase responses.The minimum number of attenuation zeros is estimated,and some examples areincluded.展开更多
A fast parameter estimation algorithm is discussed for a polyphase coded Continuous Waveform(CW) signal in Additive White Gaussian Noise(AWGN).The proposed estimator is based on the sum of the modulus square of the am...A fast parameter estimation algorithm is discussed for a polyphase coded Continuous Waveform(CW) signal in Additive White Gaussian Noise(AWGN).The proposed estimator is based on the sum of the modulus square of the ambiguity function at the different Doppler shifts.An iterative refinement stage is proposed to avoid the effect of the spurious peaks that arise when the summation length of the estimator exceeds the subcode duration.The theoretical variance of the subcode rate estimate is derived.The Monte-Carlo simulation results show that the proposed estimator is highly accurate and effective at moderate Signal-to-Noise Ratio(SNR).展开更多
The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subd...The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subduction. A similar feature of the deformation in the Dabieshan UHP metamorphic rocks implies that these different tectonic units share the same geodynamic background. The early stage of deformation can be preserved on account of their relatively shallower subduction than that for UHP rocks. On the basis of an analysis of the geo- logical structure and geochronological results, five deformational stages have been recognized: a D1-Early compressional deformation which represents the continental subduction; a D2-Early exhumation deformation producing a syn-convergence exhumation; a D3-Main deformation, represented by an exhumation deformation with Late Triassic age; a D4-Doming and its margin extensional gravity collapse deformation and finally a D5-regional extensional deformation of Cretaceous that was mostly introduced by the migmatization and plutonism.展开更多
In recent years, close attention has been paid to the study of liposomes as the carrier of the anticancerous drug, which has many advantages in the therapeutics, such as increasing the toxicity of the drug. alleviatin...In recent years, close attention has been paid to the study of liposomes as the carrier of the anticancerous drug, which has many advantages in the therapeutics, such as increasing the toxicity of the drug. alleviating metamorphosis and immunity reaction; improving the biological utilization ratio of the drug; selectively killing and inhibiting the cancer cells or checking the reproduction of the cancer cells, and so on. At present, peo-展开更多
Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation in...Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation inversion history of the Bomun sub-basin in the Gyeongju area of SE Korea.The inferred ENE compression direction(σHmax)based on paleostress analysis of the fault system,displacing Miocene sediments and SSDS,corresponds to the current stress field.The widespread occurrence of clear liquefaction structures and the vertical repetition of SSDS indicate substantial seismic activity during the basin opening stage.Brittle deformation features observed at both outcrop-and microstructural-scale along the faults suggest a reactivation as reverse faulting associated with a tilting process.The tectonic history of the study area is distinguished by SSDS associated with seismic activity,and reverse faulting associated with inversion process under ENE orientedσHmax.The Environmental Seismic Intensity Scale(ESI-07)based on the SSDS indicates seismic intensity of IX-X,which might be related with the opening of the Bomun sub-basin.Therefore,detailed analyses of SSDS could provide valuable insights on the dynamics of local geology and contribute to further extensive research on seismic hazards and basin inversion.展开更多
A new filamentous cyanobacterial strain(CHAB 4127)was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin,China.The polyphasic approach combining mo...A new filamentous cyanobacterial strain(CHAB 4127)was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin,China.The polyphasic approach combining morphological,ultrastructural,ecological,and molecular features was used to characterize this studied strain.The strain is morphologically similar to the Microcoleus-like cyanobacterial taxa under light microscopy,and the radial arrangement of thylakoids is also consistent with that of Microcoleus-like groups.The phylogenetic position of CHAB 4127 based on 16S rRNA gene sequences,is shown to be clearly clustered into an independent clade with the newly established genus Microcoleusiopsis.The maximum similarity of 16S r RNA gene of the studied strain with other existing related cyanobacterial taxa is 93.97%,and the ITS secondary structures is also obviously different from other members of Microcoleaceae.Based on all the above evidence,we proposed the establishment of this novel cyanobacterial genus as Neomicrocoleus,with its type species,Neomicrocoleus tianjinensis.展开更多
The hot deformation behavior of homogenized zinc alloy was investigated through uniaxial compression test on a Gleeble-1500 thermal-mechanical simulator within a temperature range of 230-380°C and a strain rate r...The hot deformation behavior of homogenized zinc alloy was investigated through uniaxial compression test on a Gleeble-1500 thermal-mechanical simulator within a temperature range of 230-380°C and a strain rate range of 0.01-10 s -1 ,the corresponding flow curves and their characters were determined and analyzed,and microstructures were studied by optical,SEM and TEM microscopy.The results indicated that the microstructure evolution of zinc alloy during hot deformation involves the spheroidization of the phase of TiZn15,coarsening of the precipitated phase and dynamic recrystallization（DRX）of the phase of matrix,leading to the formation of the polyphase（η＋ε＋TiZn15）structure.The spheroidization of the phase of TiZn15 during hot deformation was beneficial to the particle nucleation stimulated and then promoted to DRX of matrix.The dynamic recrystallization grain size of the matrix phase decreased firstly and then increased with elevating the temperature,and the degree of DRX became more complete when the strain rate and strain became larger.Hot deformation accelerated the diffusion of Cu atom,which resulted in the coarsening of the precipitated phase.Thus,the microstructure was refined owing to the pinning effect of the precipitated phase.展开更多
The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between ...The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between the Minab Fault in Iran, and the Ornach-Nal Fault in Pakistan. The ongoing oceanic subduction characterizes this belt between the Iranian Plateau and the Tibetan Plateau, both of which were generated by collision of Eurasian with the Arabian and Indian plates, and provides an ideal target to recover the tectonic history of subduction. The western Makran located in Iran can be subdivided into four units: The North Makran ophiolitic mélange, the Inner Makran, the Outer Makran, and the Coastal Makran. Based on our detailed structural analysis and geochronological dating, we obtain several new results that can help us to better understand the structural evolution:(1) The North Makran ophiolitic mélange includes thick piles of volcanic rocks and limestone that directly cover the mantle peridotite, so it is likely to be part of an Early Cretaceous volcanic arc by our zircon dating at ~115 Ma on mafic intrusions;(2) The entire western Makran underwent three phases of deformation. D1 is characterized by top-to-the S/SW thrusting as evidence by southward emplacement of the ophiolitic mélange onto the Eocene sedimentary rocks. D2 deformation strongly folded the pre-late Miocene/early Pliocene strata that also corresponds to the final emplacement of the ophiolite to the surface. D3 structures extends in a N-S direction with top-to-the W kinematics that overthrust the Miocene sandstone onto the Pliocene fluvial sediments along the Minab Fault;(3) Combined with geological and geochronological relationship, D1 occurred at ~45-35 Ma, D2 initiated in middle Miocene and ended with a regional late Miocene-early Pliocene uncomformity, and D3 structures are still active as the subduction continues.展开更多
基金supports from the National 973 Project on western China No.2001CB409804the key project of National Natural Science Foundation of China No.49832040.
文摘Studies show that the Tianshan orogenic belt was built in the late stage of the Paleozoic, as evidenced by the Permian red molasses and foreland basins, which are distributed in parallel with the Tianshan belt, indicating that an intense folding and uplifting event took place. During the Triassic, this orogenic belt was strongly eroded, and basins were further developed. Starting from the Jurassic, a within-plate regional extension occurred, forming a series of Jurassic-Paleogene extensional basins in the peneplaned Tianshan region. Since the Neogene, a collision event between the Indian and the Eurasian plates that took place on the southern side of the Tianshan belt has caused a strong intra-continental orogeny, which is characterized by thrusting and folding. Extremely thick coarse conglomerate and sandy conglomerate of the Xiyu Formation of Neogene System were accumulated unconformably on the Tianshan piedmont. Studies have revealed that the strong compression caused by the Indian-Eurasian collision had a profound influence over the orogenic belt in the hinterland, and MesozoiC-Cenozoic brittle deformed structures superposed on the ductile deformed Paleozoic rocks. The Mesozoic extensional basins were converted into Cenozoic compressional basins. The deformation in the basins is featured by step thrusts and fault-related folds. Statistics of joints show that the principal compressive stress since the Neogene is in a N-S direction. Meanwhile, owing to the underthrusting of the basin toward the orogenic belt, the Paleozoic strata were thrust on the Meso-Cenozoic rocks as tectonic slices, revealing distinct kinematic features in different geologic units. The basin-range coupling zones are characterized by intensive compression, folding and thrusting, accompanied by local sub-E-W-trending strike-slip faults. In the Tianshan region, Cenozoic thrusting is the most common basin-range coupling mode. The folding and faulting of Mesozoic sedimentary rocks, spontaneous combustion of Jurassic coal layers and formation of sintered rocks, the Cenozoic earthquakes and active faulting, and the unique mosaic pattern of basin-range framework of Xinjiang are all products of tectonism since the Neogene.
基金This study is funded by the Major State Basic Research Development Program （G1999075506）the National Natural Science Foundation of China （40372094 and 49972067）.
文摘Different scales of structural data reveal a complex deformation history of ultrahigh- pressure （UHP） rocks exposed in the Weihai-Rongcbeng area, NE Sulu （northern Jiangsu-eastern Shandong）, eastern China. Excluding pre-UHP deformations, at least five major sequential deformational stages （D1-Ds） are recognized. The first deformation （DO produced a weak foliation and lineation in massive eclogites. The foliated eclogite with a dominant foliation containing a stretching and mineral lineation was developed during the I）2 deformation. Both the D1 and D2 deformations occurred under UHP metamorphic conditions, and are well preserved in the eclogite bodies. D3 structures which developed shortly after the formation of granulite/amphibolite facies symplectites are characterized by imbricated associations marked by a regional, steeply dipping foliation, compositional layering, eclogite boudinage, isoclinal folds and reverse ductile shear zones. The D3 deformation was accompanied by decompressional partial melting. A regional, gently dipping amphibolite facies foliation and stretching lineation, low-angle detachments, and dome- and arc-shaped structures formed during the D4 deformation stage dominate to some degree the map pattern of the Weihai-Rongcbeng UHP domain. The last stage of deformation （Ds） gave rise to the final exhumation of the UHP rocks. Ds is characterized by development of brittle-dominated high-angle faulting associated with emplacement of large volmnes of undeformed granite plutons and dykes dated at 134-100 Ma. The deformational and metamorphic sequence followed by the UHP rocks in the Weihai-Rongcheng area is similar to that studied in the entire Dabie-Sulu UHP and HP metamorphic belts from microscopic to mapping scale. Based on structural data, combined with available petrographic, metamorphic and geochronological data, a speculative tectonic evolutionary model for the Dabie-Sulu UHP and IIP belts is proposed, involving continental subduction/collision between the Sino-Korean and Yangtze cratons and subsequent polyphase exhumation histories of the UHP and IIP metamorphic rocks.
文摘The modelling, design and implementation of a high-speed programmable polyphase finite impulse response (FIR) filter with field programmable gate array (FPGA) technology are described. This FIR filter can run automatically according to the programmable configuration word including symmetry/asymmetry, odd/even taps, from 32 taps up to 256 taps. The filter with 12 bit signal and 12 bit coefficient word-length has been realized on a Xilinx VirtexⅡ-v1500 device and operates at the maximum sampling frequency of (160 MHz.)
文摘In this paper, we describe resourceefficient hardware architectures for softwaredefined radio （SDR） frontends. These architectures are made efficient by using a polyphase channelizer that performs arbitrary sample rate changes, frequency selection, and bandwidth control. We discuss area, time, and power optimization for field programmable gate array （FPGA） based architectures in an Mpath polyphase filter bank with modified Npath polyphase filter. Such systems allow resampling by arbitrary ratios while simultaneously performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. A nonmaximally decimated polyphase filter bank, where the number of data loads is not equal to the number of M subfilters, processes M subfilters in a time period that is either less than or greater than the Mdataload ＇ s time period. We present a loadprocess architecture （LPA） and a runtime architecture （RA） （based on serial polyphase structure） which have different scheduling. In LPA, Nsubfilters are loaded, and then M subfilters are processed at a clock rate that is a multiple of the input data rate. This is necessary to meet the output time constraint of the down-sampled data. In RA, Msubfilters processes are efficiently scheduled within Ndataload time while simultaneously loading N subfilters. This requires reduced clock rates compared with LPA, and potentially less power is consumed. A polyphase filter bank that uses different resampling factors for maximally decimated, underdecimated, overdecimated, and combined upand downsampled scenarios is used as a case study, and an analysis of area, time, and power for their FPGA architectures is given. For resourceoptimized SDR frontends, RA is superior for reducing operating clock rates and dynamic power consumption. RA is also superior for reducing area resources, except when indices are prestored in LUTs.
文摘This paper presents efficient processing engines for software-defined radio （SDR） front-ends. These engines, based on a polyphase channelizer, perform arbitrary sample-rate changes, frequency selection, and bandwidth control. This paper presents an M-path polyphase filter bank based on a modified N-path polyphase filter. Such a system allows resampling by arbitrary ratios while performing baseband aliasing from center frequencies at Nyquist zones that are not multiples of the output sample rate. This resampling technique is based on sliding cyclic data load interacting with cyclic-shifted coefficients. A non-maximally-decimated polyphase filterbank （where the number of data loads is not equal to the number of M subfilters） processes M subfilters in a time period that is less than or greater than the M data loads. A polyphase filter bank with five different resampling modes is used as a case study for embedded resamp/ing in SDR front-ends. These modes are （i） maximally decimated, （ii） Under-decimated, （iii） over-decimated, and combined up- and down-sampling with （iv） single stride length, and （v） multiple stride lengths. These modes can be used to obtain any required rational sampling rate change in an SDR front-end based on a polyphase channelizer. They can also be used for translation to and from arbitrary center frequencies that are unrelated to the output sample rates.
文摘Rheological properties of polyphase rocks play an important role in the dynamics of the lithosphere and asthenosphere. However, such fundamental issues have not been well resolved. A theoretical analysis has been made to develop expressions for the flow laws of polyphase rocks in terms of the volume fractions and flow laws of their constituent phases. The flow strengths predicted by the proposed model for common crustal and upper mantle rocks such as granite, diorite, diabase and lherzolite, and for synthetic two phase composites such as forsterite enstatite and water ice ammonia dehydrate aggregates are in good agreement with previously determined experimental values. The proposed theoretical model allows one to calculate, to the first approximation, the flow laws of a large number of polyphase rocks at geologic conditions based on the experimentally determined flow laws of a relatively small number of monomineralic aggregates.
文摘A novel software tool for optimization and synthesis of RF CMOS polyhase filters(PPFs),PPFOPTIMA,is developed.In the optimization engine,genetic algorithm is adopted to avoid local optima.Experiments on PPFOPTIMA demonstrate that it is an efficient design aid for design and optimization of RF CMOS PPFs.
文摘The configuration of a brushless DC torque motor is introduced. According to the fundamental relation of the armature winding current and the air gap flux density, the ripple torque caused by the electrical errors of a resolver is approached. And a polyphase multipole resolver is developed in the brushless DC torque motor. Finally, the experimental results are presented to illustrate the improvement of ripple torque in the brushless DC torque motor with the polyphase multipole resolver.
文摘An efficient single-carrier symbol synchronization method is proposed in this paper,which can work under a very low oversampling rate.This method is based on the frequency aliasing squared timing recovery assisted by pilot symbols and time domain filter.With frequency aliasing squared timing recovery with pilots,it is accessible to estimate timing error under oversampling rate less than 2.The time domain filter simultaneously performs matched-filtering and arbitrary interpolation.Because of pilot assisting,timing error estimation can be free from alias and self noise,so our method has good performance.Compared with traditional time-domain methods requiring oversampling rate above 2,this method can be adapted to any rational oversampling rate including less than 2.Moreover,compared with symbol synchronization in frequency domain which can operate under low oversampling rate,our method saves the complicated operation of conversion between time domain and frequency domain.By low oversampling rate and resource saving filter,this method is suitable for ultra-high-speed communication systems under resource-restricted hardware.The paper carries on the simulation and realization under 64QAM system.The simulation result shows that the loss is very low(less than 0.5 dB),and the real-time implementation on field programmable gate array(FPGA)also works fine.
文摘It is well known that IIR digital filters require quite fewer computations,comparedwith FIR filters,in order to meet stringent magnitude specifications when the phase distortioncan be tolerated.An approximately linear phase,however,can be also obtained with the IIRfilter by making use of a technique without increasing the complexity.Based on a certain numberof attenuation zeros in the pass band,a new approach is developed for the design of polyphasewave digital filters with exact magnitude responses and Chebyshev approximation of the desiredphase responses.The minimum number of attenuation zeros is estimated,and some examples areincluded.
文摘A fast parameter estimation algorithm is discussed for a polyphase coded Continuous Waveform(CW) signal in Additive White Gaussian Noise(AWGN).The proposed estimator is based on the sum of the modulus square of the ambiguity function at the different Doppler shifts.An iterative refinement stage is proposed to avoid the effect of the spurious peaks that arise when the summation length of the estimator exceeds the subcode duration.The theoretical variance of the subcode rate estimate is derived.The Monte-Carlo simulation results show that the proposed estimator is highly accurate and effective at moderate Signal-to-Noise Ratio(SNR).
基金the Chinesc National"973"Project(Grant No.G1999075506)the National Natural Science Foundation of China(Grant No.40202021)A post-doctor grant for Lin W.from the JSPS(02060)is also acknowledged.
文摘The Beihuaiyang metamorphic zone was formed by the Early Mesozoic collision of the North and South China Blocks. It consisted of the Foziling and Luzhenguan complexes and was thought to have never afforded a deep subduction. A similar feature of the deformation in the Dabieshan UHP metamorphic rocks implies that these different tectonic units share the same geodynamic background. The early stage of deformation can be preserved on account of their relatively shallower subduction than that for UHP rocks. On the basis of an analysis of the geo- logical structure and geochronological results, five deformational stages have been recognized: a D1-Early compressional deformation which represents the continental subduction; a D2-Early exhumation deformation producing a syn-convergence exhumation; a D3-Main deformation, represented by an exhumation deformation with Late Triassic age; a D4-Doming and its margin extensional gravity collapse deformation and finally a D5-regional extensional deformation of Cretaceous that was mostly introduced by the migmatization and plutonism.
文摘In recent years, close attention has been paid to the study of liposomes as the carrier of the anticancerous drug, which has many advantages in the therapeutics, such as increasing the toxicity of the drug. alleviating metamorphosis and immunity reaction; improving the biological utilization ratio of the drug; selectively killing and inhibiting the cancer cells or checking the reproduction of the cancer cells, and so on. At present, peo-
基金supported by a grant(2022-MOIS62-001(RS-2022-ND640011))from the National Disaster Risk AnalysisManagement Technology in Earthquake funded by the Ministry of Interior and Safety(MOIS,Korea).
文摘Deformed soft-sediment deformation structures(SSDS)can indicate polyphase deformation events and provide valuable insights into the inversion process of a basin.Herein,we present the Miocene–Quaternary deformation inversion history of the Bomun sub-basin in the Gyeongju area of SE Korea.The inferred ENE compression direction(σHmax)based on paleostress analysis of the fault system,displacing Miocene sediments and SSDS,corresponds to the current stress field.The widespread occurrence of clear liquefaction structures and the vertical repetition of SSDS indicate substantial seismic activity during the basin opening stage.Brittle deformation features observed at both outcrop-and microstructural-scale along the faults suggest a reactivation as reverse faulting associated with a tilting process.The tectonic history of the study area is distinguished by SSDS associated with seismic activity,and reverse faulting associated with inversion process under ENE orientedσHmax.The Environmental Seismic Intensity Scale(ESI-07)based on the SSDS indicates seismic intensity of IX-X,which might be related with the opening of the Bomun sub-basin.Therefore,detailed analyses of SSDS could provide valuable insights on the dynamics of local geology and contribute to further extensive research on seismic hazards and basin inversion.
基金the Zhejiang Provincial Natural Science Foundation of China(No.LD21C030001)the National Natural Science Foundation of China(No.31970219)。
文摘A new filamentous cyanobacterial strain(CHAB 4127)was successfully isolated from the algal mat during the field investigation of the open channel from Luanhe River to Tianjin,China.The polyphasic approach combining morphological,ultrastructural,ecological,and molecular features was used to characterize this studied strain.The strain is morphologically similar to the Microcoleus-like cyanobacterial taxa under light microscopy,and the radial arrangement of thylakoids is also consistent with that of Microcoleus-like groups.The phylogenetic position of CHAB 4127 based on 16S rRNA gene sequences,is shown to be clearly clustered into an independent clade with the newly established genus Microcoleusiopsis.The maximum similarity of 16S r RNA gene of the studied strain with other existing related cyanobacterial taxa is 93.97%,and the ITS secondary structures is also obviously different from other members of Microcoleaceae.Based on all the above evidence,we proposed the establishment of this novel cyanobacterial genus as Neomicrocoleus,with its type species,Neomicrocoleus tianjinensis.
基金Project(2009BAE71B03)supported by the National Key Technology Support Program of China During the 11th Five-year Plan Period
文摘The hot deformation behavior of homogenized zinc alloy was investigated through uniaxial compression test on a Gleeble-1500 thermal-mechanical simulator within a temperature range of 230-380°C and a strain rate range of 0.01-10 s -1 ,the corresponding flow curves and their characters were determined and analyzed,and microstructures were studied by optical,SEM and TEM microscopy.The results indicated that the microstructure evolution of zinc alloy during hot deformation involves the spheroidization of the phase of TiZn15,coarsening of the precipitated phase and dynamic recrystallization（DRX）of the phase of matrix,leading to the formation of the polyphase（η＋ε＋TiZn15）structure.The spheroidization of the phase of TiZn15 during hot deformation was beneficial to the particle nucleation stimulated and then promoted to DRX of matrix.The dynamic recrystallization grain size of the matrix phase decreased firstly and then increased with elevating the temperature,and the degree of DRX became more complete when the strain rate and strain became larger.Hot deformation accelerated the diffusion of Cu atom,which resulted in the coarsening of the precipitated phase.Thus,the microstructure was refined owing to the pinning effect of the precipitated phase.
基金granted by the National Natural Science Foundation of China(91855103,91855207 and 91855212)the Ministry of Science and Technology(2016YFC0600401 and 2016YFC0600102)the State Key Laboratory of Lithospheric Evolution(SKL-Q201801)
文摘The Makran represents a huge accretionary wedge in SE Iran that resulted from the long-lasting subduction of the Neotethys Ocean since the Mesozoic. From west to east, this accretionary wedge extends ~1000 km between the Minab Fault in Iran, and the Ornach-Nal Fault in Pakistan. The ongoing oceanic subduction characterizes this belt between the Iranian Plateau and the Tibetan Plateau, both of which were generated by collision of Eurasian with the Arabian and Indian plates, and provides an ideal target to recover the tectonic history of subduction. The western Makran located in Iran can be subdivided into four units: The North Makran ophiolitic mélange, the Inner Makran, the Outer Makran, and the Coastal Makran. Based on our detailed structural analysis and geochronological dating, we obtain several new results that can help us to better understand the structural evolution:(1) The North Makran ophiolitic mélange includes thick piles of volcanic rocks and limestone that directly cover the mantle peridotite, so it is likely to be part of an Early Cretaceous volcanic arc by our zircon dating at ~115 Ma on mafic intrusions;(2) The entire western Makran underwent three phases of deformation. D1 is characterized by top-to-the S/SW thrusting as evidence by southward emplacement of the ophiolitic mélange onto the Eocene sedimentary rocks. D2 deformation strongly folded the pre-late Miocene/early Pliocene strata that also corresponds to the final emplacement of the ophiolite to the surface. D3 structures extends in a N-S direction with top-to-the W kinematics that overthrust the Miocene sandstone onto the Pliocene fluvial sediments along the Minab Fault;(3) Combined with geological and geochronological relationship, D1 occurred at ~45-35 Ma, D2 initiated in middle Miocene and ended with a regional late Miocene-early Pliocene uncomformity, and D3 structures are still active as the subduction continues.
