In tensor theory, the parallel factorization （PARAFAC）decomposition expresses a tensor as the sum of a set of rank-1tensors. By carrying out this numerical decomposition, mixedsources can be separated or unknown sys...In tensor theory, the parallel factorization （PARAFAC）decomposition expresses a tensor as the sum of a set of rank-1tensors. By carrying out this numerical decomposition, mixedsources can be separated or unknown system parameters can beidentified, which is the so-called blind source separation or blindidentification. In this paper we propose a numerical PARAFACdecomposition algorithm. Compared to traditional algorithms, wespeed up the decomposition in several aspects, i.e., search di-rection by extrapolation, suboptimal step size by Gauss-Newtonapproximation, and linear search by n steps. The algorithm is ap-plied to polarization sensitive array parameter estimation to showits usefulness. Simulations verify the correctness and performanceof the proposed numerical techniques.展开更多
Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in tw...Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in two orthogonal polarization channels. Firstly, signal model and signal process are advanced under narrowband condition. Secondly, measurement performances of two typical IPR waveforms are analyzed in detail. At last, field experiments are carried out using X-band IPR system designed by National University of Defense Technology （NUDT）, China. Compared with results obtained by alternative polarization measurement scheme, following results can be obtained： the difference of relative amplitude measurement results is smaller than 2 dB and that of relative phase measurement results is smaller than 10？, verifying the validity of instantaneous polarization measurement scheme.展开更多
Dear Colleagues, We invite you to submit a article, a review, a letter, or a trend to a special issue on＂The rapid change of Arctic sea ice and its possible effects on high- and mid-latitude weather and climate＂, o...Dear Colleagues, We invite you to submit a article, a review, a letter, or a trend to a special issue on＂The rapid change of Arctic sea ice and its possible effects on high- and mid-latitude weather and climate＂, or another special issue on ＂The current status on the ecosystem of Antarctic Peninsula＂ of the Journal Advances in Polar Science （APS）.展开更多
当干扰信号的空域和极化域特征与目标信号相似时,采用空极化域联合抗干扰技术在消除干扰的同时也会抑制目标信号,导致干扰对消后信干噪比(signal to interference plus noise ratio,SINR)低于雷达系统需求,从而形成干扰对消盲区。针对...当干扰信号的空域和极化域特征与目标信号相似时,采用空极化域联合抗干扰技术在消除干扰的同时也会抑制目标信号,导致干扰对消后信干噪比(signal to interference plus noise ratio,SINR)低于雷达系统需求,从而形成干扰对消盲区。针对这一现象,通过在空域、极化域与空极化域分别建立交替极化阵列对消盲区模型,推导了对消盲区位置和大小的数学表达式,从而给出了交替极化阵列对消盲区的数学表征方法。进而分析了交替极化阵列对消盲区的分布规律与影响因素,研究发现阵元间距能够显著影响交替极化阵列对消盲区的分布,在相同条件下交替极化阵列对消盲区大于共点极化阵列对消盲区,结果表明交替极化阵列虽然通过减少天线数目降低了设备成本,但增大了阵列的对消盲区。然后,对消盲区模型进行了数值仿真,仿真结果验证了理论分析。最后,利用信道模拟器搭建了实验平台,信道模拟实验测得的对消盲区与理论值基本一致,再次证明了分析结论的有效性。展开更多
探讨了不同极化方式下Pb(Mg_(1/3)Nb_(2/3))O_(3)–0.3Pb Ti O_(3)(PMN-0.3PT)单晶的压电性能的变化。实验结果表明,相比于直流电极化,交流电极化后PMN-0.3PT单晶的压电系数d33从1421 pC/N提升至1857 pC/N,相对介电系数εr从4800提升至6...探讨了不同极化方式下Pb(Mg_(1/3)Nb_(2/3))O_(3)–0.3Pb Ti O_(3)(PMN-0.3PT)单晶的压电性能的变化。实验结果表明,相比于直流电极化,交流电极化后PMN-0.3PT单晶的压电系数d33从1421 pC/N提升至1857 pC/N,相对介电系数εr从4800提升至6650,压电系数与相对介电系数分别提升了30.7%和38.5%。为探究交流电优化机理,采用了实验和模拟相结合的方法,从极化畴结构演化的角度给出了解释。用压电力显微镜对PMN-0.3PT的畴结构进行了扫描,并利用相场模型对PMN-0.3PT的畴结构演化进行了表征,实验和模拟结果展现出相同的演化趋势;同时建立了相应的晶格演化模型进行解释。对于未极化的PMN-0.3PT单晶,畴结构呈现随机分布的状态;经过直流电极化后,电畴沿偏向电场的方向翻转,畴结构形貌呈现树枝状;在交流电极化后,PMN-0.3PT内部只存在两个不同极化方向,畴结构形貌呈现条带状。数值计算的结果表明,随着极化方式由无极化到直流极化再到交流极化,PMN-0.3PT的畴壁能从727.578变化到160.060再到57.910,伴随着畴壁能的减小,畴壁密度逐渐降低,这是导致压电性能提升的主要原因。该研究成果对深入理解弛豫铁电材料电畴结构与压电性能的内在联系及作用机理有非常重要的意义,并为优化铁电材料的压电性能给出了可行方案。展开更多
1 Aims andscope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of d...1 Aims andscope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.展开更多
1 Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of ...1 Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.展开更多
Due to the unique geographical location and sensitive response to global climate changes,the Antarctic region plays an important role in paleoclimate researches,and attracts great attentions from various scholars.One ...Due to the unique geographical location and sensitive response to global climate changes,the Antarctic region plays an important role in paleoclimate researches,and attracts great attentions from various scholars.One 324 cm long sediment core(ANT29-P7-09)was obtained from Prydz Bay,Antarctica,during the 29th Chinese National Antarctic Research Expedition.Based on sediment particle size,TOC,δ13C analyses and magnetism data,the authors show that the dominant magnetic minerals are ferrimagnetic pseudo single domain(PSD)-multi domain(MD)magnetite.Variations in the paleoenvironmental records allow us to define 4 zones in the core.These zones outline the climatic variations in the region since the late Early Pleistocene,including a warm period,a transitional period,and a cold period.The magnetic particle assemblage varies with glacial-interglacial cycles.Abrupt changes in particle size,TOC content,and geomagnetism occur at 102–90 cm deep in the core,indicating a sudden warming in the Antarctic region,signaling the onset of the Holocene.The authors identified 3 additional climatic signals in the middle part of the core(232–162 cm)that show unexpected cooling events during the warm period in Prydz Bay,Antarctica.展开更多
Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Scie...Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Science （APS）. APS is an international, peer-reviewed journal jointly sponsored by the Polar Research Institute of China （PRIC） and the Chinese Arctic and Antarctic Administration （CAA）. It is a quarterly journal published in March, June, September and December by Science Press of China and circulated internationally （ISSN 1674-9928, CN 31-2050/P）. Articles published in APS are free of charge with generous funding from PRIC. For more details, please visit the APS＇s websites. Thank you in advance for your consideration to submit manuscripts to this special issue, and we encourage you to share this announcement broadly with interested colleagues.展开更多
1 Aims and scope Advances in Polar Science(APS) is an international, English-language, peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range ...1 Aims and scope Advances in Polar Science(APS) is an international, English-language, peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines. It is sponsored by the Polar Research Institute of China. APS is a true open-access journal, with no publication fees and all articles are freely accessible as soon as they are released.展开更多
1Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of d...1Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.展开更多
基金supported by the National Natural Science Foundation of China(61571131)the Technology Innovation Fund of the 10th Research Institute of China Electronics Technology Group Corporation(H17038.1)
文摘In tensor theory, the parallel factorization （PARAFAC）decomposition expresses a tensor as the sum of a set of rank-1tensors. By carrying out this numerical decomposition, mixedsources can be separated or unknown system parameters can beidentified, which is the so-called blind source separation or blindidentification. In this paper we propose a numerical PARAFACdecomposition algorithm. Compared to traditional algorithms, wespeed up the decomposition in several aspects, i.e., search di-rection by extrapolation, suboptimal step size by Gauss-Newtonapproximation, and linear search by n steps. The algorithm is ap-plied to polarization sensitive array parameter estimation to showits usefulness. Simulations verify the correctness and performanceof the proposed numerical techniques.
基金supported by the National Natural Science Foundationof China (60736006 60802078)
文摘Adopting ＂simultaneous transmitting, simultaneous receiving＂ operational scheme, instantaneous polarization radar （IPR） can measure target polarization scattering matrix （PSM） using only once target echoes in two orthogonal polarization channels. Firstly, signal model and signal process are advanced under narrowband condition. Secondly, measurement performances of two typical IPR waveforms are analyzed in detail. At last, field experiments are carried out using X-band IPR system designed by National University of Defense Technology （NUDT）, China. Compared with results obtained by alternative polarization measurement scheme, following results can be obtained： the difference of relative amplitude measurement results is smaller than 2 dB and that of relative phase measurement results is smaller than 10？, verifying the validity of instantaneous polarization measurement scheme.
文摘Dear Colleagues, We invite you to submit a article, a review, a letter, or a trend to a special issue on＂The rapid change of Arctic sea ice and its possible effects on high- and mid-latitude weather and climate＂, or another special issue on ＂The current status on the ecosystem of Antarctic Peninsula＂ of the Journal Advances in Polar Science （APS）.
文摘当干扰信号的空域和极化域特征与目标信号相似时,采用空极化域联合抗干扰技术在消除干扰的同时也会抑制目标信号,导致干扰对消后信干噪比(signal to interference plus noise ratio,SINR)低于雷达系统需求,从而形成干扰对消盲区。针对这一现象,通过在空域、极化域与空极化域分别建立交替极化阵列对消盲区模型,推导了对消盲区位置和大小的数学表达式,从而给出了交替极化阵列对消盲区的数学表征方法。进而分析了交替极化阵列对消盲区的分布规律与影响因素,研究发现阵元间距能够显著影响交替极化阵列对消盲区的分布,在相同条件下交替极化阵列对消盲区大于共点极化阵列对消盲区,结果表明交替极化阵列虽然通过减少天线数目降低了设备成本,但增大了阵列的对消盲区。然后,对消盲区模型进行了数值仿真,仿真结果验证了理论分析。最后,利用信道模拟器搭建了实验平台,信道模拟实验测得的对消盲区与理论值基本一致,再次证明了分析结论的有效性。
文摘探讨了不同极化方式下Pb(Mg_(1/3)Nb_(2/3))O_(3)–0.3Pb Ti O_(3)(PMN-0.3PT)单晶的压电性能的变化。实验结果表明,相比于直流电极化,交流电极化后PMN-0.3PT单晶的压电系数d33从1421 pC/N提升至1857 pC/N,相对介电系数εr从4800提升至6650,压电系数与相对介电系数分别提升了30.7%和38.5%。为探究交流电优化机理,采用了实验和模拟相结合的方法,从极化畴结构演化的角度给出了解释。用压电力显微镜对PMN-0.3PT的畴结构进行了扫描,并利用相场模型对PMN-0.3PT的畴结构演化进行了表征,实验和模拟结果展现出相同的演化趋势;同时建立了相应的晶格演化模型进行解释。对于未极化的PMN-0.3PT单晶,畴结构呈现随机分布的状态;经过直流电极化后,电畴沿偏向电场的方向翻转,畴结构形貌呈现树枝状;在交流电极化后,PMN-0.3PT内部只存在两个不同极化方向,畴结构形貌呈现条带状。数值计算的结果表明,随着极化方式由无极化到直流极化再到交流极化,PMN-0.3PT的畴壁能从727.578变化到160.060再到57.910,伴随着畴壁能的减小,畴壁密度逐渐降低,这是导致压电性能提升的主要原因。该研究成果对深入理解弛豫铁电材料电畴结构与压电性能的内在联系及作用机理有非常重要的意义,并为优化铁电材料的压电性能给出了可行方案。
文摘1 Aims andscope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.
文摘1 Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.
基金This work was financially supported by“Global change and air-sea interaction”(GASI-GEOGE-05,GASI-04-01-02,GASI-02-PAC-CJ07,GAST-GEOGE-03)National Natural Science Foundation of China(41576069,41576063)Zhejiang Qingshan Lake Innovation Platform for Marine Science and Technology(2017E80001).
文摘Due to the unique geographical location and sensitive response to global climate changes,the Antarctic region plays an important role in paleoclimate researches,and attracts great attentions from various scholars.One 324 cm long sediment core(ANT29-P7-09)was obtained from Prydz Bay,Antarctica,during the 29th Chinese National Antarctic Research Expedition.Based on sediment particle size,TOC,δ13C analyses and magnetism data,the authors show that the dominant magnetic minerals are ferrimagnetic pseudo single domain(PSD)-multi domain(MD)magnetite.Variations in the paleoenvironmental records allow us to define 4 zones in the core.These zones outline the climatic variations in the region since the late Early Pleistocene,including a warm period,a transitional period,and a cold period.The magnetic particle assemblage varies with glacial-interglacial cycles.Abrupt changes in particle size,TOC content,and geomagnetism occur at 102–90 cm deep in the core,indicating a sudden warming in the Antarctic region,signaling the onset of the Holocene.The authors identified 3 additional climatic signals in the middle part of the core(232–162 cm)that show unexpected cooling events during the warm period in Prydz Bay,Antarctica.
文摘Dear Colleagues, We would like to invite you to submit manuscripts to a special issue entitled ＂Current Research on Atmospheric Aerosols and Trace Gases over the Polar Regions＂ of the Journal Advances in Polar Science （APS）. APS is an international, peer-reviewed journal jointly sponsored by the Polar Research Institute of China （PRIC） and the Chinese Arctic and Antarctic Administration （CAA）. It is a quarterly journal published in March, June, September and December by Science Press of China and circulated internationally （ISSN 1674-9928, CN 31-2050/P）. Articles published in APS are free of charge with generous funding from PRIC. For more details, please visit the APS＇s websites. Thank you in advance for your consideration to submit manuscripts to this special issue, and we encourage you to share this announcement broadly with interested colleagues.
文摘1 Aims and scope Advances in Polar Science(APS) is an international, English-language, peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines. It is sponsored by the Polar Research Institute of China. APS is a true open-access journal, with no publication fees and all articles are freely accessible as soon as they are released.
文摘1Aims and scope Advances in Polar Science(APS)is an international,English-language,peer-reviewed journal that publishes scientific research results concerning the Arctic and Antarctic regions across a broad range of disciplines.It is sponsored by the Polar Research Institute of China.APS is a true open-access journal,with no publication fees and all articles are freely accessible as soon as they are released.
