A 3-D supramolecular framework, [Er（pybz）2（Hnds）（H2O）2]·H2O （1, Hpybz = 4- pyridin-4-yl-benzoic acid, H2nds = naphthalene-1,5-disulfonic acid）, based on lanthanide ions and mixed ligands has been hydrothe...A 3-D supramolecular framework, [Er（pybz）2（Hnds）（H2O）2]·H2O （1, Hpybz = 4- pyridin-4-yl-benzoic acid, H2nds = naphthalene-1,5-disulfonic acid）, based on lanthanide ions and mixed ligands has been hydrothermally synthesized. The structure was determined by single-crystal X-ray diffraction and further characterized by IR, elemental analysis and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system, space group P21/n with a = 9.849（2）, b = 22.526（5）, c = 17.167（4） A, β =105.461（4）° and V = 3670.9（2） A^3. In 1, two seven-coordinated Er^3＋ ions are bridged by two pybz^- ligands to form a dimeric [Er2（COO）2] unit, which is further orderly linked by carboxyl of pybz^-ligand to obtain a 1-D chain running along the a axis. Interestingly, significant H-bonding and π-π stacking interactions link the neighboring parallel chains leading to a 3-D supramolecular network structure which displays 1-D rhombus open channels （17.2A× 22.5A）.展开更多
Since early 1980s, in particular during the period of "7th and 8th Five-year Plan"(1986- 1995), China’s power sector has adopted successfully the policy of multichannel and diversified financing to raise fu...Since early 1980s, in particular during the period of "7th and 8th Five-year Plan"(1986- 1995), China’s power sector has adopted successfully the policy of multichannel and diversified financing to raise funds as well as encouraging to introduce foreign funds for its development and has got tremendous achievements. This paper describes the channels and methods to raise funds from both domestic and international market to meet huge demand of funds amounting to 690 billion yuan RMBfor the sector development during "gth Fiveyear Plan" period (1996-2000) in the wake of overall reform and achievements in the past decade. This paper also presents the legal framework supporting to suit for the methods and channels of the financing. Some suggestions have been made.展开更多
Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its d...Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets. The topic of moving-target detection in clutter has been extensively studied, and there are many methods that are used to detect moving targets, such as displaced phase center antenna （DPCA） method, along-track interfero-metric （ATI） phase, space-time adaptive processing （STAP）, or some other metrics. A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods, namely, DPCA and ATI. The statistical test metric for multi-channel SAR-GMTI is established in a simple form, via the definition of the complex central Wishart distribution, to deduce the statistics of the test metric, and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case, namely the X^2 distribution. The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector, and derives the constant false alarm rate （CFAR） detector tests for separating moving targets from clutter.展开更多
基于DVB-RCS(Digital Video Broadcasting and Return Channel via Satellite)卫星无线接入技术标准的宽带卫星通信技术已成为目前研究的热点。现有的DVB-RCS标准以物理层规范为主,其中的无线资源管理技术等重要的宽带无线接入功能的定...基于DVB-RCS(Digital Video Broadcasting and Return Channel via Satellite)卫星无线接入技术标准的宽带卫星通信技术已成为目前研究的热点。现有的DVB-RCS标准以物理层规范为主,其中的无线资源管理技术等重要的宽带无线接入功能的定义缺乏系统性,缺少具有可实现性的无线资源管理体系的描述,尚不能构成一个较完整的卫星宽带无线接入体系结构。针对宽带卫星通信的无线资源管理技术,提出一种基于DVB-RCS的宽带卫星无线资源管理体系结构,给出其主要功能模块设计及关键技术分析,并就可能的实现方法和进一步研究方向进行讨论。展开更多
基金supported by the National Natural Science Fund for Distinguished Young Scholars of China (No. 20725101)the 973 Program (No. 2006CB932904)+2 种基金the NSF of Fujian Province (Nos. E0510030 and 2008F3120)the Knowledge Innovation Program of CAS (No. KJCX2.YW.H01)NNSFC (No. 20521101)
文摘A 3-D supramolecular framework, [Er（pybz）2（Hnds）（H2O）2]·H2O （1, Hpybz = 4- pyridin-4-yl-benzoic acid, H2nds = naphthalene-1,5-disulfonic acid）, based on lanthanide ions and mixed ligands has been hydrothermally synthesized. The structure was determined by single-crystal X-ray diffraction and further characterized by IR, elemental analysis and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system, space group P21/n with a = 9.849（2）, b = 22.526（5）, c = 17.167（4） A, β =105.461（4）° and V = 3670.9（2） A^3. In 1, two seven-coordinated Er^3＋ ions are bridged by two pybz^- ligands to form a dimeric [Er2（COO）2] unit, which is further orderly linked by carboxyl of pybz^-ligand to obtain a 1-D chain running along the a axis. Interestingly, significant H-bonding and π-π stacking interactions link the neighboring parallel chains leading to a 3-D supramolecular network structure which displays 1-D rhombus open channels （17.2A× 22.5A）.
文摘Since early 1980s, in particular during the period of "7th and 8th Five-year Plan"(1986- 1995), China’s power sector has adopted successfully the policy of multichannel and diversified financing to raise funds as well as encouraging to introduce foreign funds for its development and has got tremendous achievements. This paper describes the channels and methods to raise funds from both domestic and international market to meet huge demand of funds amounting to 690 billion yuan RMBfor the sector development during "gth Fiveyear Plan" period (1996-2000) in the wake of overall reform and achievements in the past decade. This paper also presents the legal framework supporting to suit for the methods and channels of the financing. Some suggestions have been made.
基金the National Natural Science Foundation of China (60472097 and 60502054)
文摘Synthetic aperture radar （SAR） systems have become an important tool for fine-resolution mapping and other remote sensing operations. The multi-channel SAR ground moving-target indication （GMTI） must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets. The topic of moving-target detection in clutter has been extensively studied, and there are many methods that are used to detect moving targets, such as displaced phase center antenna （DPCA） method, along-track interfero-metric （ATI） phase, space-time adaptive processing （STAP）, or some other metrics. A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods, namely, DPCA and ATI. The statistical test metric for multi-channel SAR-GMTI is established in a simple form, via the definition of the complex central Wishart distribution, to deduce the statistics of the test metric, and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case, namely the X^2 distribution. The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector, and derives the constant false alarm rate （CFAR） detector tests for separating moving targets from clutter.
文摘基于DVB-RCS(Digital Video Broadcasting and Return Channel via Satellite)卫星无线接入技术标准的宽带卫星通信技术已成为目前研究的热点。现有的DVB-RCS标准以物理层规范为主,其中的无线资源管理技术等重要的宽带无线接入功能的定义缺乏系统性,缺少具有可实现性的无线资源管理体系的描述,尚不能构成一个较完整的卫星宽带无线接入体系结构。针对宽带卫星通信的无线资源管理技术,提出一种基于DVB-RCS的宽带卫星无线资源管理体系结构,给出其主要功能模块设计及关键技术分析,并就可能的实现方法和进一步研究方向进行讨论。
