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Search Results: 1 - 10 of 38886 matches for " Zhen Zhu "
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An Open-framework Strontium Phosphate Containing a Novel 412 Cages
Zhen Zhu
Asian Social Science , 2010, DOI: 10.5539/ass.v6n10p201
Abstract: A novel strontium phosphite open-framework H2[Sr6(HPO3)7] (denoted as ZZ-2, ZZ = Zhen Zhu) was hydrothermally synthesized by using isophorondiamine (IPDA) as the trial structure-directing agent. Single crystal structure refinement discloses that ZZ-2 crystallizes in the trigonal space group R-3 with the cell parameters of a = 16.410(2) , b =16.410(2) , c = 6.8651(14) , ? = 114.61(5)°, ? = 90°, V = 1601.0(5) 3, Z = 3. The structure of ZZ-2 is constructed by eight coordinated SrO8 and HPO3 pseudo pyramids. A novel 412 cages existed in the structure with a proton located in the center of the cage. the P-H bonds stretch in all cages, hydrogen proton at the center of the cage to balance framework.
Synthesis and Characterization of a Layered Uranium Phosphites
Zhen Zhu
Asian Social Science , 2010, DOI: 10.5539/ass.v6n3p135
Abstract: A novel layered oxouranium phosphite open-structure [C10H24N2]?[(UO2)2(HPO3)3]?H2O (denoted as ZZ-1) was hydrothermally synthesized by using isophorondiamine (IPDA) as the template. Single crystal structure refinement discloses that ZZ-1 crystallizes in the monoclinic space group P21c with the cell parameters of a = 18.347(4) , b = 6.7341(13) , c = 20.639(4) , β = 114.61(3)°, V = 2318.2(8) 3 , Z = 2. The structure of ZZ-1 is constructed by UO7 monomer, U2O12 dimer and HPO3 groups. The monomeric UO7 or dimeric U2O12 is connected by HPO3 groups to form two types of 4-ring chains. An undulating sheet is then generated by connecting these two types of chains via HPO3 bridges. The layer structure is formed by stacking the sheet along the direction with the organoamine cations and water molecules intercalated in the interlayer spaces with strong H-bonds to the framework oxygen atoms. Although a mixture of cis and trans IPDA is used, only cis PDA serves as the template. A typical green light emission of UO22+ is observed when excited by 266 nm laser.
Selective Spin Injection Controlled by Electrical way in Ferromagnet/Quantum Dot/Semiconductor system
Zhen-Gang Zhu
Physics , 2008, DOI: 10.1016/j.physleta.2007.07.081
Abstract: Selective and large polarization of current injected into semiconductor (SC) is predicted in Ferromagnet (FM)/Quantum Dot (QD)/SC system by varying the gate voltage above the Kondo temperature. In addition, spin-dependent Kondo effect is also revealed below Kondo temperature. It is found that Kondo resonances for up spin state is suppressed with increasing of the polarization P of the FM lead. While the down one is enhanced. The Kondo peak for up spin is disappear at P=1.
Semiconducting layered blue phosphorus: A computational study
Zhen Zhu,David Tomanek
Physics , 2014, DOI: 10.1103/PhysRevLett.112.176802
Abstract: We investigate a previously unknown phase of phosphorus that shares its layered structure and high stability with the black phosphorus allotrope. We find the in-plane hexagonal structure and bulk layer stacking of this structure, which we call `blue phosphorus', to be related to graphite. Unlike graphite and black phosphorus, blue phosphorus displays a wide fundamental band gap and should exfoliate easily to form quasi-2D structures suitable for electronic applications. We study a likely transformation pathway from black to blue phosphorus and discuss possible ways to synthesize the new structure.
Jordan Higher All-Derivable Points in Nest Algebras
Nannan Zhen,Jun Zhu
Mathematics , 2011,
Abstract: Let $\mathcal{N}$ be a non-trivial and complete nest on a Hilbert space $H$. Suppose $d=\{d_n: n\in N\}$ is a group of linear mappings from Alg$\mathcal{N}$ into itself. We say that $d=\{d_n: n\in N\}$ is a Jordan higher derivable mapping at a given point $G$ if $d_{n}(ST+ST)=\sum\limits_{i+j=n}\{d_{i}(S)d_{j}(T)+d_{j}(T)d_{i}(S)\}$ for any $S,T\in Alg \mathcal{N}$ with $ST=G$. An element $G\in Alg \mathcal{N}$ is called a Jordan higher all-derivable point if every Jordan higher derivable mapping at $G$ is a higher derivation. In this paper, we mainly prove that any given point $G$ of Alg$\mathcal{N}$ is a Jordan higher all-derivable point. This extends some results in \cite{Chen11} to the case of higher derivations.
Radar Imaging of Sidelobe Suppression Based on Sparse Regularization  [PDF]
Xiaoxiang Zhu, Guanghu Jin, Feng He, Zhen Dong
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.43017

Synthetic aperture radar based on the matched filter theory has the ability of obtaining two-di- mensional image of the scattering areas. Nevertheless, the resolution and sidelobe level of SAR imaging is limited by the antenna length and bandwidth of transmitted signal. However, for sparse signals (direct or indirect), sparse imaging methods can break through limitations of the conventional SAR methods. In this paper, we introduce the basic theory of sparse representation and reconstruction, and then analyze several common sparse imaging algorithms: the greed algorithm, the convex optimization algorithm. We apply some of these algorithms into SAR imaging using RadBasedata. The results show the presented method based on sparse construction theory outperforms the conventional SAR method based on MF theory.

The Research of Railway Line State Detection Signal Processing Method Based on EMD  [PDF]
Wen-Fa Zhu, Hui-Zhen Ma, Xiao-Dong Chai, Shu-Bin Zhen
Open Journal of Safety Science and Technology (OJSST) , 2015, DOI: 10.4236/ojsst.2015.52008
Abstract: In this paper, an EMD de-noising algorithm is proposed based on the statistical feature of random noise, which can eliminate the noise impaction digital integrator generated by the collected railway line state detection signals using strap-down inertial technology. Firstly, the first IMF component of the noise-dominant modes treated by the process “random sort-sum-average-reconstruc-tion”, the signal-to-noise ratio is improved while the noise power is weakened in this process. Then the signal-to-noise cut-off can be determined according to the characters of noise autocorrelation function. Finally, the global threshold could be selected by the noise-dominant mode component, so as to realize the function of filtering. The simulation and validation based on the collected railway line acceleration data using the EMD de-noising algorithm show that the noise in railway line state acceleration detection signals can be effectively eliminated using this method.
Progress in Proteomics


生物工程学报 , 2001,
Abstract: Proteomics, the large\|scale analysis of proteins, will contribute greatly to our understanding of gene function in the post\|genome era. Proteomics uses a combination of sophisticated techniques including two\|dimensional(2D) gel electrophoresis, mass spectrometry, yeast two\|hybrid system, bioinformatics, etc. to characterize, to quantify, and to analyze cellular proteins in a global way. The application of proteomics provides major opportunities to elucidate disease mechanisms and to identify new therapeutic targets.This review aims to explain the definition of proteomics and then to outline proteomic techniques. Finally, applications to the study of human disease are briefly discussed.
Formation and Stability of Cellular Carbon Foam Structures:An {\em Ab Initio} Study
Zhen Zhu,David Tománek
Physics , 2012, DOI: 10.1103/PhysRevLett.109.135501
Abstract: We use ab initio density functional calculations to study the formation and structural as well as thermal stability of cellular foam-like carbon nanostructures. These systems with a mixed $sp^2/sp^3$ bonding character may be viewed as bundles of carbon nanotubes fused to a rigid contiguous 3D honeycomb structure that can be compressed more easily by reducing the symmetry of the honeycombs. The foam may accommodate the same type of defects as graphene, and its surface may be be stabilized by terminating caps. We postulate that the foam may form under non-equilibrium conditions near grain boundaries of a carbon-saturated metal surface.
Is female preference for large sexual ornaments due to a bias to escape predation risk?
Zhen Zhu, Tae Won Kim, Jae Choe
BMC Evolutionary Biology , 2012, DOI: 10.1186/1471-2148-12-33
Abstract: First, we observed responses of mate-searching female U. lactea to courting males with full-sized, half-sized and no semidomes which were experimentally manipulated. Females had a directional preference for males with bigger semidomes within normal variation. Thereafter, we tested the effect of predation risk on the female bias in the non-courtship context. When threatened by an avian mock predator, females preferentially approached burrows with full-sized semidomes regardless of reproductive cycles (i.e. reproductive periods and non-reproductive periods). When the predator cue was absent, however, females preferred burrows with semidomes without discriminating structure size during reproductive periods but did not show any bias during non-reproductive periods.Results indicate that selection for the size of courtship structures in U. lactea may have an origin in the function to reduce predation risk, but that the preference for males with structures may have evolved by female choice, independent of predation pressure.Sexual selection can be used to explain the evolution of various male secondary sexual characters which are used as courtship signals [1,2]. A number of experimental studies provide evidence that females prefer males with conspicuous sexual traits [3-9]. Females may benefit from choosing males with strong signals directly by reducing their own predation risk [10-14] or by providing better parental care to their offspring [15-17]. Females also may acquire indirect benefit by transmitting high genotypic quality of males to their offspring [3,6,18,19]. The preference for the existence of the signal and the preference for signal intensity are often regarded to have the same origin [8,20-23]. However, the preferences for a signal per se and for intensity of the signal may have different origins when the two components serve different functions. No studies to date have tried to separate the origins of preferences for these two components of courtship signals.
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