Beam Pattern Synthesis Based on Hybrid Optimization Algorithm

As conventional methods for beam pattern synthesis can not always obtain the desired optimum pattern for the arbitrary underwater acoustic sensor arrays,a hybrid numerical synthesis method based on adaptive principle and genetic algorithm was presented in this paper.First,based on the adaptive theory,a given array was supposed as an adaptive array and its sidelobes were reduced by assigning a number of interference signals in the sidelobe region.An initial beam pattern was obtained after several iterations and adjustments of the interference intensity,and based on its parameters,a desired pattern was created.Then,an objective function based on the difference between the designed and desired patterns can be constructed.The pattern can be optimized by using the genetic algorithm to minimize the objective function.A design example for a double-circular array demonstrates the effectiveness of this method.Compared with the approaches existing before,the proposed method can reduce the sidelobe effectively and achieve less synthesis magnitude error in the mainlobe.The method can search for optimum attainable pattern for the specific elements if the desired pattern can not be found.

Parametric array differential Pattern time delay shift coding underwater acoustic communication in the under-ice environment

In order to meet the demands of underwater acoustic communication in under ice environment,a differential Pattern time delay shift coding underwater acoustic communication method based on parametric array is introduced in this paper.The under ice underwater acoustic channel is characterized by heavy multipath transmission.Under this model,a parametric array emission method of Pattern signal is derived and the system performance is analyzed.A broadband low frequency sound waves with narrow beam-pattern,which will reduce the interface reflections and suppress the effects of multipath transmission,can be obtained by the emission method.The Songhua River under ice trial results show that there is an anti-multipath property and a higher data rate in the under-ice acoustic channel in proposed approach.

Growth and Patterning of Pt Nanowires on Silicon Substrates

This paper describes a simple procedure for growing dense fi lms of Pt nanowires directly on silicon substrates by modifying the surface through chemical or physical means.In the former,a self-assembled monolayer of(3-mercaptopropyl)-trimethoxysilane(MPTMS)is applied which can strongly bind Pt(0)nuclei to the surface through Pt S linkages.Once attached,the Pt(0)nuclei can act as catalytic sites for the growth of Pt nanowires along the〈111〉direction.Alternately,relief features are physically created on the surface in order to generate nucleation and binding sites for Pt(0)nuclei,due to the higher free energy associated with a rough surface.Additionally,Pt nanowires have been successfully produced in well-defined patterns by scouring grooves on the silicon surface or by photochemically patterning the MPTMS monolayers with a shadow mask.We have also measured the electrochemical properties of these immobilized or patterned Pt nanowires.The results provide an effective route to producing dense fi lms of Pt nanowires with high surface areas for various electrochemical applications.

A multifunctional upconversion nanoparticles probe for Cu^(2+)sensing and pattern recognition of biothiols

Lanthanide-doped upconversion nanoparticles(Ln-UCNPs)are a new type of nanomaterials with excellent fluorescence properties,which are well applied in fluorescent biosensing.Herein we developed a multifunctional probe based on the surface engineering of core-shell structure UCNPs with polyacrylic acid(PAA).The developed PAA/UCNPs probe could be highly selective to detect and respond to Cu^(2+) at different pH.Cu^(2+) could easily combine with the carboxylate anion of PAA to quench the fluorescence of UCNPs.Therefore,we creatively proposed a fluorescent array sensor(PAA/UCNPs-Cu^(2+)),in which the same material acted as the sensing element by coupled with pH regulation for pattern recognition of 5 thiols.It could also easily identify the chiral enantiomer of cystine(L-Cys-and D-Cys),and distinguish their mixed samples with different concentrations,and more importantly,it could be combined with urine samples to detect actual level of homocysteine(Hcys)to provide a new solution for judging whether the human body suffers from homocystinuria.

Hybrid supraparticles of carbon dots/porphyrin for multifunctional tongue-mimic sensors

Supraparticles(SPs),such as assembly of inorganic components with organic,have made tremendous attention in biochemical analysis,which represents a novel but challenging research orientation.Herein,a single-SPs multifunctional fluorescent sensor array has been developed for high-throughput detection of heavy metal ions in biofluids,which is based on an inorganic/organic hybrid SPs consisting of carbon dots(CDs)and an easily available porphyrin[5,10,15,20-tetra(4-carboxyphenyl)porphyrin(TCPP)].TCPP can aggregate with the CDs to form the assembly(CDs/TCPP SPs)through the electrostatic andπ-πstacking interaction.There are two independent and clearly separated fluorescence emission peaks at 470 and 668 nm in the resultant CDs/TCPP SPs under 380 nm excitation.As a proof-of concept design,F 470,F 668,F 668/F 470 of SPs are chosen as three sensor components to constitute our sensor array.With the addi-tion of metal ions,three sensor components can generate different fluorescence response patterns for discriminating 11 heavy metal ions via principal component analysis(PCA).Additionally,thiols can read-ily capture Cu^(2+)to switch the fluorescence of CDs/TCPP initially altered by Cu^(2+).Hence,CDs/TCPP-Cu^(2+)ensemble is further demonstrated to be a powerful sensor array for pattern recognition of 7 thiols and even chiral recognition of cysteine enantiomers.This novel strategy avoids the tanglesome synthesis of multiple sensing probes and dedicates an innovative method for the facile establishment of tongue-mimic sensors,which would prospectively sprout more homologous assumptions to broaden its application toward more biosensing fields.

Analysis of airborne antenna using a FEM-UTD hybrid method

In this paper,the near-field vector components were used to combine the FEM method and the uniform-geometrical theory of diffraction(UTD)method for analyzing phased array antenna mounted on an airborne platform.First,HFSS,a set of software based on finite element method(FEM),was utilized to find the near-field vector components of the phased array antennas,and then these vector components were used as the source of the UTD method to get the disturbed radiation pattern.Numerical results show that the hybrid of the two methods not only extends the use of the UTD program,but also effectively solves this type of challenging problems.