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security-Enhanced Directional modulation Based on Two-Dimensional m-WFRFT

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China Communications 2024年第5期21卷 229-248页

作者： zhou Zhuang Luo Junshan Wang shilian Xia Guojiang school of Electronic science National University of Defense TechnologyChangsha 410073China Beijing Institute of Astronautical systems Engineering Beijing 100076China

Directional modulation(Dm)is one of the most promising secure communication ***,when the eavesdropper is co-located with the legitimate receiver,the conventional Dm has the disadvantages of weak anti-scanning capability,anti-deciphering capability,and low secrecy *** response to these problems,we propose a twodimensional multi-term weighted fractional Fourier transform aided Dm scheme,in which the legitimate receiver and the transmitter use different transform terms and transform orders to encrypt and decrypt the confidential *** order to further lower the probability of being deciphered by an eavesdropper,we use the subblock partition method to convert the one-dimensional modulated signal vector into a twodimensional signal matrix,increasing the confusion of the useful *** results demonstrate that the proposed Dm scheme not only provides stronger anti-deciphering and anti-scanning capabilities but also improves the secrecy rate performance of the system.

关键词： bit error rate directional modulation phased array secrecy rate weighted fractional Fourier transform

Influence of stearic acid surface modification on flowability and agglomeration of battery grade Li_(2)CO_(3)powder

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Particuology 2024年第9期92卷 263-277页

作者： ming zhou Lithium Industry Center Zhejiang New Era Zhongneng Technology Co.Ltd.Shaoxing312000China

This work investigates the flow and agglomeration behaviors of battery grade Li_(2)CO_(3)powder and the influence of stearic acid surface *** degree of agglomeration is directly related to the uniformity of Li_(2)CO_(3)and its powder *** to the Chinese National Nonferrous.m.tal Industry standard,battery grade Li_(2)CO_(3)powder has D50 equal to 3–8μm which belongs to a micron-sized superfine ***,with the extension of storage time,the serious agglomeration phenomenon occurs due to the large specific surface area and rough and irregular powder *** Hausner ratio(HR)of the unmodified s.m.le increases from 1.14 to 1.41,and the corresponding flowability is classified as good to ***,among s.m.les with doping stearic acid,the optimum amount of it is 0.10 wt%which exhibits an extremely stable HR value from 1.14 to ***,after 156 days,the repose angle(AR)obtained for s.m.les without surface modification and using 0.10 wt%stearic acid are calculated to be 49°and 28°,*** on the values of HR and AR,the flowability of the unmodified s.m.le is poor while the s.m.le modified with 0.10 wt%of stearic acid still maintain excellent powder flow ***,The Limn_(2)O_(4)cathode material synthesized from modified Li_(2)CO_(3)powder with a stearic acid content of 0.10 wt%exhibits good crystallinity and comparable electrochemical performance to that prepared by commercial Li_(2)CO_(3).These results indicate that stearic acid has the potential to be an ideal modifier for battery grade Li_(2)CO_(3)powder that needs to be kept for a long time.

关键词： Battery grade Li_(2)CO_(3)powder Flowability surface modification stearic acid

High-power,electrically-driven continuous-wave 1.55-μm si-based multi-quantum well lasers with a wide operating temperature range grown on wafer-scale InP-on-si(100)heterogeneous substrate

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Light(science & Applications) 2024年第8期13卷 1512-1523页

作者： Jialiang sun Jiajie Lin min zhou Jianjun Zhang Huiyun Liu Tiangui You Xin Ou National Key Laboratory of materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyCASShanghai 200050China Center of materials science and Optoelectronics Engineering University of Chinese Academy of Sciences100049 BeijingChina College of Information science and Engineering Jiaxing UniversityJiaxing 314001China Beijing National Laboratory for Condensed matter Physics Institute of PhysicsChinese Academy of Sciences100190 BeijingChina Department of Electronic and Electrical Engineering University College LondonLondon WC1E 7JEUK

A reliable,efficient and electrically-pumped si-based laser is considered as the main challenge to achieve the integration of all key building blocks with silicon *** the impressive advances that have been made in developing 1.3-μm si-based quantum dot(QD)lasers,extending the wavelength window to the widely used 1.55-μm telecommunication region remains *** this study,we develop a novel photonic integration method of epitaxial growth of III-V on a wafer-scale InP-on-si(100)(InPOs)heterogeneous substrate fabricated by the ion-cutting technique to realize integrated lasers on si *** ion-cutting plus epitaxial growth approach decouples the correlated root causes of many detrimental dislocations during heteroepitaxial growth,namely lattice and domain *** this approach,we achieved state-of-the-art performance of the electrically-pumped,continuouswave(CW)1.55-μm si-based laser with a room-temperature threshold current density of 0.65 kA/cm-2,and output power exceeding 155mW per facet without facet coating in CW *** lasing at 120℃ and pulsed lasing at over 130℃ were *** generic approach is also applied to other material systems to provide better performance and more functionalities for photonics and microelectronics.

关键词： pumped power quantum

mechanical Properties and Electronic structures of m(m=Ti,V,Cr,mn and Fe)Dopedβ-si_(3)N_(4) from First-Principle

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Journal of Wuhan University of Technology(materials science) 2024年第3期39卷 639-644页

作者：龙敏黄福祥 XU Liangyu LI Xuemei YANG zhou LENG Yue mEI shini school of materials science and Engineering Chongqing University of TechnologyChongqing 400054China

The structures.m.chanical properties and electronic structures of m metals.m.Ti,V,Cr,mn and Fe)dopedβ-si_(3)N_(4) were investigated by First-principles calculations within *** calculated lattice parameters ofβ-si_(3)N_(4) were consistent with previous *** cohesive energy and formation enthalpy show that initialβ-si_(3)N_(4) has the highest structural *** calculated elastic constant and the Voigt-Reuss-Hill approximation indicate that elastic moduli ofβ-si_(3)N_(4) are slightly reduced by m *** on Poisson’s and Pugh’s ratio,β-si_(3)N_(4) is a ductile material and the toughness ofβ-si_(3)N_(4) increases with m doping,and Fe doping exhibited the best *** results of density of states,charge distributions and overlapping populations indicate thatβ-si_(3)N_(4) has the strong covalent and ionic bond strength between N and si.

关键词： first-principles β-si_(3)N_(4) mechanical properties electronic structure

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： s.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)s.m.les exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on s.m.images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： s.m.conductor TiO_(2) Rare earths Congo red methylene blue solar spectrum Photodegradation

Influence of cerium ions on structure-dependent magnetic properties of Ba-sr m-type hexaferrite nanocrystals

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Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： Ram A.Pawar sunil m.Patange P.m.Dighe sher singh meena Abdullah GAl-sehemi mehboobali Pannipara santosh s.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia solid state Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized s.m.les was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPs data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FEs.m.profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.s.m.and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-sr hexaferrite Ce^(3+)substitution XPs saturation magnetization Coercivity m?ssbauer spectroscopy

Effect of CO_(2) Opposing multiple Jets on Thermoacoustic Instability and NO_(x) Emissions in a Lean-Premixed model Combustor

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Journal of Thermal science 2024年第1期33卷 207-221页

作者： zhou Hao HU Liubin Institute for Thermal Power Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China

This paper experimentally studied the effect of CO_(2) opposing multiple jets on the thermoacoustic instability and NO_(x) emissions in a lean-premixed model *** feasibility was verified from three variables:the CO_(2) jet flow rate,hole numbers,and hole diameters of the *** indicate that the control effect of thermoacoustic instability and NO_x emissions show a reverse trend with the increase of open area ratio on the whole,and the optimal jet flow rate range is 1-4 L/min with CO_(2) opposing multiple *** this flow rate range,the amplitude and frequency of the dynamic pressure and heat release signals CH~* basically decrease as the CO_(2) flow rate increases,which avoids high-frequency and high-amplitude thermoacoustic *** amplitude-damped ratio of dynamic pressure and CH*can reach as high as 98.75% and 93.64% with an optimal open area ratio of 3.72%.NO_(x) emissions also decrease as the jet flow rate increases,and the maximum suppression ratio can reach 68.14%.Besides,the flame shape changes from a steep inverted "V" to a more flat "m",and the flame length will become shorter with CO_(2) opposing multiple *** research achieved the synchronous control of thermoacoustic instability and NO_(x) emissions,which could be a design reference for constructing a safer and cleaner combustor.

关键词： thermoacoustic instability lean-premixed model combustor CO_(2)opposing multiple jets open area ratio NO_(x)emissions

Enhanced red luminescence of Ca_(3)si_(2−x)m_(x)O_(7):Eu^(3+)(m=Al,P)phosphors via partial substitution of si^(4+) for applications in white light-emitting diodes

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Rare metals 2024年第2期43卷 736-748页

作者： Yu-Hao ma Xi Gao Wen-Tao Zhang Zhen-Rui Yang zhou Zhao Chen Qu College of materials and Chemistry and Chemical Engineering Chengdu University of TechnologyChengdu610059China state Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China International Advanced Energy science Research and Education Center Graduate School of Energy ScienceKyoto UniversityYoshida-HonmachiKyoto606-8501Japan

A red-emitting phosphor Ca_(2.91)si_(2)O_(7):0.09Eu^(3+) with partial Al^(3+)/P^(5+) substitution on si^(4+) was synthesized via a s.m.le solid-state method,and the effects of the introduction of the m^(3+/5+)(m=Al,P)ions on the crystal structure and photoluminescence performance of Ca_(2.91)si_(2−x)m_(x)O_(7):0.09Eu^(3+) phosphors were *** X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDs),and X-ray photoelectron spectroscopy(XPs)results revealed that the structure of Ca_(3)si_(2)O_(7) remained the s.m. after the introduction of Al^(3+) and P^(5+) *** characteristic emission of Eu^(3+)-doped Ca_(3)si_(2−x)m_(x)O_(7) phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the^(5)D_(0)→^(7)F_(2)and^(5)D_(0)→^(7)F_(1) electron transitions of Eu^(3+) *** the partial substitution of Al^(3+) and P^(5+),the red emission intensities of the Ca_(2.91)si_(2)O_(7):0.09Eu^(3+) phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu^(3+).meanwhile,the luminescence intensities of the Ca_(2.91)si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+) and Ca_(2.91)si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) phosphors at 210℃ were 79.36%and 77.53%of those at 30°C,respectively,indicating their excellent thermal ***,the as-prepared Ca_(2.91)si_(1.96)Al_(0.04)O_(7):0.09Eu^(3+)and Ca_(2.91)si_(1.94)P_(0.06)O_(7):0.09Eu^(3+) red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity *** s.m.ary,Al^(3+)/P^(5+)-substituted Ca_(2.91)si_(2)O_(7):0.09Eu^(3+) can serve as red-emitting phosphors for applications in w-LEDs.

关键词： Ca_(3)si_(2)O_(7) Red-emitting phosphor structure substitution Luminescence enhancement Crystal-field effect White light-emitting diode

Effect of radiative loss.m.chanisms on FIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： C.Y.morassuti A.P.L silva L.A.O.Nunes s.m.Lima L.H.C.Andrade Optical and Photothermal spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology Center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of são Carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(s.m.les doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for s.m.les doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths