The one-dimensional kinetic Ising model: A series expansion study

Exact power series expansions (through eight terms) in the time are derived for relaxation in the one-dimensional Ising model with nearest-neighbor interactions for a general rate parameter where the activation energy is a variable fraction of the energy required to break nearest-neighbor bonds. It is found that the qualitative nature of the relaxation is very dependent on this parameter, varying from nearly simple exponential decay (as with Glauber dynamics) for an intermediate value of this parameter, to an initial rate of change that is either much slower or faster than a simple exponential at the extremes of the range of variation of the parameter. The rate equations for the limit of rapid internal diffusion (internal equilibration) are integrated for several special values of the rate parameter. In general the internal equilibration approximation is not a good representation of the relaxation except when the relaxation is similar to Glauber dynamics.     

Dissipative and Autonomous Square‐Wave Self‐Oscillation of a Macroscopic Hybrid Self‐Assembly under Continuous Light Irradiation

Building a bottom‐up supramolecular system to perform continuously autonomous motions will pave the way for the next generation of biomimetic mechanical systems. In biological systems, hierarchical molecular synchronization underlies the generation of spatio‐temporal patterns with dissipative structures. However, it remains difficult to build such self‐organized working objects via artificial techniques. Herein, we show the first example of a square‐wave limit‐cycle self‐oscillatory motion of a noncovalent assembly of oleic acid and an azobenzene derivative. The assembly steadily flips under continuous blue‐light irradiation. Mechanical self‐oscillation is established by successively alternating photoisomerization processes and multi‐stable phase transitions. These results offer a fundamental strategy for creating a supramolecular motor that works progressively under the operation of molecule‐based machines.     

A novel strategy for avian species identification by cytochrome b gene

We report a DNA-based test that can be applied to any avian species so that the amplicon can be used in species identification. The need for the test arose from the requirement to enforce the Wildlife Conservation Act in Taiwan where over 150 avian species are protected. It is difficult to enforce the law if no gross morphology is present and hence there is a requirement to develop a DNA test. This study uses a novel strategy for avian species identification by the cytochrome b gene where a series of primer pairs producing amplicons of decreasing size was designed. The test is designed to produce the largest possible amplicon based upon the quality of the DNA in the sample. A total of 331 avian samples were tested representing 40 species. Sequencing of the amplicons revealed limited intraspecies variation and that no DNA sequence was shared by samples from two different avian species. The closest genetic distance among the 40 species was 0.059 which was between Lonchura punctulata and Estrilda melpoda based upon data from the smallest amplicon. A DNA databank including 138 sequence types from 331 samples tested, representing 40 different species, was constructed in this study. A blind test was used to determine the value for this system for forensic applications that successfully identified the species.     

High Diversity Transceiver for Low Power Differentially Encoded OFDM System

In this work, we investigate differentially encoded blind transceiver design in low signal‐to‐noise ratio (SNR) regimes for orthogonal frequency‐division multiplexing (OFDM) signaling. Owing to the fact that acquisition of channel state information is not viable for short coherence times or in low SNR regimes, we propose a time‐spread frequency‐encoded method under OFDM modulation. The repetition (spreading) of differentially encoded symbols allows us to achieve a target energy per bit to noise ratio and higher diversity. Based on the channel order, we optimize subcarrier assignment for spreading (along time) to achieve frequency diversity of an OFDM modulated signal. We present the performance of our proposed transceiver design and investigate the impact of Doppler frequency on the performance of the proposed differentially encoded transceiver design. To further improve reliability of the decoded data, we employ capacity‐achieving low‐density parity‐check forward error correction encoding to the information bits.     

Structural diversity controlled by alkali/alkaline earth metals for heterometallic AeI/AeII-ZnII coordination polymers based on 4-nitrobenzene-1,2-dicarboxylate

Six heterometallic Zn(II) coordination polymers, Zn(H₂O)₃(FNA) (1), [NH₄]₂[Zn(H₂O)₂(FNA)₂] (2), [ZnNa₂(FNA)₂]·3H₂O (3), [ZnK₂(FNA)₂]·H₂O (4), [ZnRb₂(FNA)₂]·2H₂O (5) and [ZnMg(FNA)₂]·4H₂O (6) (H₂FNA = 4-nitrobenzene-1,2-dicarboxylic acid), were synthesised by introducing different alkali/alkaline earth (Ae^I/Ae^II) metals. These complexes exhibit diverse structures with the different Ae^I/Ae^II metals used and distinct ligand coordination modes the ions provide. For 1 and 2, the Zn(II) centres with distorted octahedra are connected by FNA to form 1-D chain structures. The Zn(II) centres in 3–6 with distorted tetrahedra are linked by FNA to form 2-D anionic grid layers. For 3–5, these 2-D anionic grid layers are connected by alkali metal (Na, K and Rb) with the O–Ae^I–O connectivity to exhibit 3-D framework structures, while 6 features a 2-D Zn–Mg network. Luminescence properties of 1–6 have been investigated.     

Allele and haplotype diversity of new multiplex of 19 ChrX‐STR loci in Han population from Guanzhong region (China)

X‐chromosomal short tandem repeats (X‐STRs) have been proved to be useful for some deficiency paternity cases in recent years. Here, we studied the genetic polymorphisms of 19 X‐STR loci (DXS10148‐DXS10135‐DXS8378, DXS10159‐DXS10162‐DXS10164, DXS7132‐DXS10079‐DXS10074‐DXS10075, DXS6809‐DXS6789, DXS7424‐DXS101, DXS10103‐HPRTB‐DXS10101 and DXS7423‐DXS10134) in 252 male and 222 female individuals from Guanzhong Han population, China. No deviation for all 19 loci was observed from the Hardy–Weinberg equilibrium. The polymorphism information content values of the panel of 19 loci were more than 0.5 with the exception of the locus DXS7423. The combined power of discrimination were 0.9999999999999999999994340 in females and 0.9999999999997662 in males, respectively; and the combined mean exclusion chances were 0.999999993764 in duos and 0.999999999997444 in trios, respectively. The haplotype diversities for all the seven clusters of linked loci were more than 0.9. The results showed that the panel of 19 X‐STR loci were powerful for forensic applications in Guanzhong Han population. Locus by locus population comparisons showed significant differences at more than seven loci between Guanzhong Han population and the groups from North America, Europe and Africa.     

可信的反馈声誉保护协作频谱感知软判决算法

协作频谱感知中信任机制的引入,起到了抑制恶意用户频谱感知数据伪造( SSDF)攻击行为的作用。然而,数据融合中心不加区分地接收协作感知结束后的反馈信息,为恶意用户带来了实施“掺沙子”攻击的机会。恶意用户向数据融合中心反馈错误的主用户频谱状态,使信任机制不能得出准确的信任值。为此,提出了一种基于反馈声誉的信任机制,考虑反馈中的个体性特征,引入反馈声誉的思想来量化认知用户信任值。同时,将信任值量化结果用于权重经典软判决算法———序贯概率比检测( SPRT)算法,消除SSDF恶意用户参与软判决数据融合的影响,形成可信序贯概率比检测算法( FSPRT)。仿真结果表明FSPRT算法的性能优于传统SPRT算法,能有效降低网络信任值计算误差,并保持较好的感知性能。     

国外声呐技术研究现状与发展趋势

概述了声呐从诞生至今的发展变化,总结了国外现役主战声呐装备型号、体制、使用国家和平台。从多功能一体、阵列构型、多基地协同、开放式体系架构四个层面分析了国外声呐技术研究现状。结合任务需求和基础技术支撑,从全自适应智能化认知、MIMO声呐、广域异质多传感器联合感知三个维度展望了声呐技术的发展趋势。