Lithuanian Journal of Physics最新文献_第5页

Model for self-assembly of Br–H and Br–Br bonded Br4Py molecules Br-H和Br-Br键合Br4Py分子的自组装模型

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-12-10 DOI: 10.3952/physics.v62i4.4820

A. Ibenskas

引用次数: 1

Microwave electromagnetic shielding effectiveness of ZnNb2O6-chopped strands composites for radar and wideband (6.5–18 GHz) applications znnb2o6 -切碎链复合材料在雷达和宽带(6.5-18 GHz)应用中的微波电磁屏蔽效果

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-10-25 DOI: 10.3952/physics.v62i3.4799

E. Şahi̇n

{"title":"Microwave electromagnetic shielding effectiveness of ZnNb2O6-chopped strands composites for radar and wideband (6.5–18 GHz) applications","authors":"E. Şahi̇n","doi":"10.3952/physics.v62i3.4799","DOIUrl":"https://doi.org/10.3952/physics.v62i3.4799","url":null,"abstract":"In this study, the traditional mixed oxide process was used to create ZnNb2O6-chopped strands composites. The single phase compound with the chemical formula ZnNb2O6 was generated after sintering at 1100°C for 4 h. For the structural investigation, various quantities of ZnNb2O6-chopped strands were generated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were carried out for the structural analysis, which indicated that the second phase did not form in ZnNb2O6. Additionally, the ZnNb2O6-strands composites were manufactured by hot pressing using the compositions of ZnNb2O6-chopped strands in various proportions and epoxy. The ZnNb2O6-chopped strands compound formed in various weights, and epoxy resin were used to fabricate microwave shielding effectiveness composites. Utilizing a network analyzer, the microwave shielding effect of ZnNb2O6-chopped strands composites was investigated in a range of 6.5–18 GHz. At a thickness of 1.5 mm, a minimum of –51.32 dB shielding effectiveness value was achieved at 6.75 GHz. The ZnNb2O6-chopped strands compounds were produced as composite and their features were characterized for shielding effectivacy. The content of components in the samples may be managed for the larger and needed frequency bands to change the microwave shielding performance.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43227101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Generation-recombination noise and other features of doped silicon in a wide temperature range 宽温度范围内掺杂硅的产生复合噪声及其他特性

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-10-25 DOI: 10.3952/physics.v62i3.4798

V. Palenskis, J. Glemza, J. Matukas

引用次数: 0

Towards wireless data transmission with compact all-electronic THz source and detector system 用紧凑的全电子太赫兹源和探测器系统实现无线数据传输

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-10-25 DOI: 10.3952/physics.v62i3.4796

A. Cesiul, K. Ikamas, D. B. But, I. Morkunaitė, T. Lisauskas, A. Lisauskas

{"title":"Towards wireless data transmission with compact all-electronic THz source and detector system","authors":"A. Cesiul, K. Ikamas, D. B. But, I. Morkunaitė, T. Lisauskas, A. Lisauskas","doi":"10.3952/physics.v62i3.4796","DOIUrl":"https://doi.org/10.3952/physics.v62i3.4796","url":null,"abstract":"This paper presents a fully-electronic wireless link operating at the 250 GHz frequency. The key elements of the developed system are the voltage-controlled harmonic oscillator implemented in 65 nm complementary metal-oxide-semiconductor technology (CMOS) and a quasi-optical detector with a resonantantenna- coupled field-effect transistor completed in 90 nm CMOS. The source is optimized for the third harmonic emission at 252 GHz with radiated power reaching up to –11 dBm (decibels with reference to one milliwatt) level. The detector has a resonance maximum of 254 GHz with a bandwidth of 25% and a minimal optical noise equivalent power of 22 pW/√−H−z . We employ an on-off keying technique for data coding and demonstrate digital signal transmission from 0.4 to 18 m distances. At 0.4 m distance and modulation frequency of 32 MHz, we achieve a 15.9 dB signal-to-noise ratio. The channel capacity of assembled communication link reaches 266 Mbit/s. However, it is limited by external electronic components – the amplifier and the modulator bandwidths. Implementing state-of-the-art high-frequency circuits should allow directly scaling the throughput to 10 Gbit/s.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42234407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Investigation of reflection bands of 1D annular photonic crystal containing double negative index material and non-magnetized plasma 含双负折射率材料和非磁化等离子体的一维环形光子晶体的反射带研究

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-10-25 DOI: 10.3952/physics.v62i3.4797

A. Aghajamali, S. K. Srivastava, C. Nayak

{"title":"Investigation of reflection bands of 1D annular photonic crystal containing double negative index material and non-magnetized plasma","authors":"A. Aghajamali, S. K. Srivastava, C. Nayak","doi":"10.3952/physics.v62i3.4797","DOIUrl":"https://doi.org/10.3952/physics.v62i3.4797","url":null,"abstract":"In this paper, optical reflectance properties of an annular photonic crystal (APC) composed of alternate layers of double negative (DNG) material and a non-magnetized plasma (NMP) layer, immersed in free space, have been theoretically investigated and studied. The reflectance spectra of the annular PC have been obtained by employing the transfer matrix method (TMM) for the cylindrical waves in the case of TEpolarized wave only. It has been found that the spectral position and width of the reflection bands of APC are greatly influenced by the variation in the thickness of DNG metamaterial and NMP layer, respectively. Interestingly, it is observed that the presence of NMP layer causes the increase in photonic band gap (PBG) whereas the DNG layer reduces the PBG. Further, the effect of azimuthal mode number (m) on the reflectance spectra shows that for m > 0, splitting in the reflection bands occurs at the frequency corresponding to the zero permeability value of DNG metamaterial layer. Moreover, with the increase in azimuthal mode number one PBG is red-shifted and the second one is blue-shifted. Finally, the effect of change in the starting radius parameter of curved surface and plasma electron density on the reflectance spectra of APC has also been studied and very interesting results have been observed.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48952774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Application of artificial neural network for the ionizing radiation particle identification by the plastic scintillation detector response 人工神经网络在塑料闪烁探测器响应电离辐射粒子识别中的应用

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-10-25 DOI: 10.3952/physics.v62i3.4800

J. Garankin, A. Plukis

{"title":"Application of artificial neural network for the ionizing radiation particle identification by the plastic scintillation detector response","authors":"J. Garankin, A. Plukis","doi":"10.3952/physics.v62i3.4800","DOIUrl":"https://doi.org/10.3952/physics.v62i3.4800","url":null,"abstract":"The separation of ionizing radiation particles is an important and challenging task, especially regarding neutrons and gamma rays. The separation of neutron and gamma radiation is necessary for safeguard purposes and control of nuclear reactions. Standard mathematical models of pulse analysis work well in the presence of large energy transfer (>1 MeV) from the particle to the detector. However, the quality of the separation decreases as the amount of transferred energy lessens, making it impossible to determine the exact type of particle at a sufficiently low-energy level. In this work, an artificial neural network model was used to solve the problem of separation at low-energy levels. The supervised machine learning (ML) model was used to analyse pulses received from the polyethylene naphthalate (PEN) scintillation detector. Several data sets after the PEN exposure to neutron/gamma (combined 239PuBe and 238PuBe source), alpha (238Pu) and beta (90Sr/90Y) sources were used to train the models. The information obtained from the separation of neutrons and gamma particles was compared with the information obtained using standard pulses delayed fluorescence analysis methods. The obtained results showed that the model was able to separate particles in the fields of low- and high-energy transfer.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43145370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

O NMR and DFT study of hydrogen bonding: Proton sharing and incipient transfer 氢键的O NMR和DFT研究：质子共享和初始转移

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-07-12 DOI: 10.3952/physics.v62i2.4744

V. Balevičius, K. Aidas, A. Marsalka, F. Kuliesius, V. Jakubkienė, S. Tumkevičius

{"title":"O NMR and DFT study of hydrogen bonding: Proton sharing and incipient transfer","authors":"V. Balevičius, K. Aidas, A. Marsalka, F. Kuliesius, V. Jakubkienė, S. Tumkevičius","doi":"10.3952/physics.v62i2.4744","DOIUrl":"https://doi.org/10.3952/physics.v62i2.4744","url":null,"abstract":"O NMR spectra of pyridine N-oxide (PyO) complexes with the acids – acetic (AA), cyanoacetic (CyA), propiolic (PA), trichloroacetic (TCA), trifluoroacetic (TFA), hydrochloric (HCl) and methanesulfonic (MSA) – as well as some related molecules with intramolecular H-bonds (4-substituted picolinic acid N-oxides) were studied in an acetonitrile (ACN) solution. In order to evaluate the effect of proton positioning along the O–H…O bond on the measured chemical shifts the full geometry optimization was carried out, and 17O magnetic shielding tensors were calculated using density functional theory (DFT). The modified hybrid functional PBE1PBE with the 6-311++G** basis set and the gauge-including atomic orbital (GIAO) approach were applied. The solvent effect was taken into account by a polarized continuum model using the integral equation formalism (IEFPCM). Two stable structures were deduced for the PyO complexes with TCA and TFA that correspond to the H-bonds with and without proton transfer (PT). Two minima on the potential surface were separated by ca 0.2 Å. The experimental 17O NMR spectra have shown that the PyO-TCA complex in ACN can be considered as H-bonding with incipient PT, whereas it is known from neutron diffraction that in its crystalline state PT occurs. The proton location in PyO-TFA due to the thermally induced proton sharing was found at the middle point. The 17O NMR data for the acids with an intramolecular H-bond (nitroPANO, PANO and methoxyPANO) deviate from the general trend. The factors that can cause it, such as the substitution effect, persistence of nano-crystallites in a solution due to a low solubility, etc., have been discussed.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47423111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The gloria mundi of SYK does not transit yet SYK的gloria mundi还没有过境

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-07-12 DOI: 10.3952/physics.v62i2.4741

D. Khveshchenko

引用次数: 1

Influence of an ultra-thin buffer layer on the growth and properties of pseudomorphic GaAsBi layers 超薄缓冲层对伪晶GaAsBi层生长和性能的影响

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-07-12 DOI: 10.3952/physics.v62i2.4742

S. Pūkienė, A. Jasinskas, A. Zelioli, S. Stanionytė, V. Bukauskas, B. Čechavičius, E. Dudutienė, R. Butkutė

{"title":"Influence of an ultra-thin buffer layer on the growth and properties of pseudomorphic GaAsBi layers","authors":"S. Pūkienė, A. Jasinskas, A. Zelioli, S. Stanionytė, V. Bukauskas, B. Čechavičius, E. Dudutienė, R. Butkutė","doi":"10.3952/physics.v62i2.4742","DOIUrl":"https://doi.org/10.3952/physics.v62i2.4742","url":null,"abstract":"A series of 100 nm-thick pseudomorphic GaAsBi layers with the Bi content varying from 0.97 to 11.2% have been grown by molecular beam epitaxy (MBE) on the semi-insulating GaAs(100) substrates buffered with an ultra-thin up to 20 nm thick GaAs layer. The main attention in this work was focused on the investigation of relaxation in the Bi induced compressively-strained GaAsBi layers containing a various content of Bi. The lattice parameters of GaAs- Bi compound and the Bi concentration have been evaluated from high resolution X-ray diffraction measurements. The relaxation values of GaAsBi layers ranging from 0.4 to 3.5% were obtained analyzing the symmetric and asymmetric reciprocal space maps of (004) and (115) planes, respectively. Also, the complex study was performed to clarify the relaxation effect on structural, morphological and optical properties of bismide layers. Optical measurements revealed a significant reduction of the energy band gap from 1.34 to 0.92 eV for the layers containing 0.97–8.6% of Bi in the GaAs lattice.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46151643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study of the aerosol particle filtration efficiency of fabrics used to manufacture non-medical face masks in Lithuania 立陶宛非医用口罩生产用织物的气溶胶颗粒过滤效率研究

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-07-12 DOI: 10.3952/physics.v62i2.4743

K. Kandrotaitė, V. Dudoitis, I. Uogintė, P. Strizak, F. Pope, K. Plauškaitė, S. Byčenkienė

{"title":"Study of the aerosol particle filtration efficiency of fabrics used to manufacture non-medical face masks in Lithuania","authors":"K. Kandrotaitė, V. Dudoitis, I. Uogintė, P. Strizak, F. Pope, K. Plauškaitė, S. Byčenkienė","doi":"10.3952/physics.v62i2.4743","DOIUrl":"https://doi.org/10.3952/physics.v62i2.4743","url":null,"abstract":"The global spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) proved to be a challenge for public health. The high demand of medical masks worldwide during the pandemic has led to a critical situation for decision-makers regarding high-quality mask supply. For this period, the World Health Organization has suggested the use of non-medical face masks (also known as ‘community’ masks) in public places to reduce the airborne spread of SARS-CoV-2. In this study, the filtration efficiency of various fabrics widely used in community masks was determined based on two main mask filtering properties: filtration efficiency (FE) and pressure drop (ΔP) according to the recommendations of the CEN Workshop Agreement (CWA) 17553:2020. The combination of FE and ΔP parameters must be considered in order to select suitable materials for public masks. The filtration efficiencies for various fabrics ranged from 6 to 100%. It was found that the composite materials have the highest FE equivalent to the requirements of a medical mask (FE > 95%), that is confirmed by high-quality parameters 16–30 kPa–1. The study found that fabrics of natural fibres (100% cotton) have a higher FE with Ag coating (18–40% before and 29–40% after coating) in the 0.54–1.50 μm particle size range.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42863627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0