Lithuanian Journal of Physics最新文献_第6页

137Cs and 239,240Pu activity concentrations distribution in waterlogged and non-boggy soils of Lithuania 137Cs和239240Pu在立陶宛积水和非沼泽土壤中的活性浓度分布

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-04-24 DOI: 10.3952/physics.v62i1.4697

L. Kazakevičiūtė-Jakučiūnienė, N. Tarasiuk, E. Maceika, R. Druteikienė, M. Konstantinova, Z. Žukauskaitė, R. Gvozdaitė, Š. Buivydas

{"title":"137Cs and 239,240Pu activity concentrations distribution in waterlogged and non-boggy soils of Lithuania","authors":"L. Kazakevičiūtė-Jakučiūnienė, N. Tarasiuk, E. Maceika, R. Druteikienė, M. Konstantinova, Z. Žukauskaitė, R. Gvozdaitė, Š. Buivydas","doi":"10.3952/physics.v62i1.4697","DOIUrl":"https://doi.org/10.3952/physics.v62i1.4697","url":null,"abstract":"Vertical distributions of 239,240Pu and 137Cs activity concentrations in the waterlogged and non-boggy soil cores sampled in the vicinity of Vilnius City and in the Varėna District were analyzed. The radionuclides appeared in the soils mainly as a result of the fallout after the nuclear weapon testing in atmosphere in 1960s and due to the Chernobyl NPP accident in 1986. The deposited radionuclides on the surface of waterlogged soils on the shores of lakes experienced processes of translocation and accumulation, therefore their total activity in the column differs from the activity in non-boggy soils. The mobility of plutonium is the highest in waterlogged organic-rich soils. Clay in the waterlogged soil significantly limits the migration of radiocesium and does not affect noticeably the mobility of plutonium. Compared with radiocesium, the mobility of plutonium in non-boggy soils is somewhat limited. So, in waterlogged and non-boggy soils, the radionuclide mobilizing factors act in the opposite directions for radiocesium and plutonium. A clear correlation between the radionuclide activity and soil organic matter content was not observed. The investigation showed that radionuclide mobility can be determined by studying radionuclide physicochemical forms in the soil, vertical profiles of radiocesium to plutonium ratios, soil composition as well as its oxidation regime.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48436368","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

Investigation of a widely-tunable subnanosecond BBO-based optical parametric amplifier 宽可调谐亚纳秒bbo光参量放大器的研究

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-04-24 DOI: 10.3952/physics.v62i1.4695

G. Stanionytė, V. Tamulienė, R. Grigonis, J. Vengelis

引用次数: 0

Quantum Jaynes–Cummings model for a two-level system with effects of parametric time- dependences 具有参数时间依赖效应的两能级系统的量子Jaynes-Cummings模型

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-04-24 DOI: 10.3952/physics.v62i1.4694

M. Berrehail, N. Benchiheub, S. Menouar, J. Choi

引用次数: 0

The combined effects of ascorbic acid and bovine serum albumin on phototransformations of hematoporphyrin derivative in aquaeous medium: Absorption and EPR spectroscopy study 抗坏血酸和牛血清白蛋白对血卟啉衍生物在水介质中光转化的联合作用:吸收和EPR光谱研究

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-04-24 DOI: 10.3952/physics.v62i1.4698

A. Marsalka, A. Kalnaityte, T. Biekša, S. Bagdonas

{"title":"The combined effects of ascorbic acid and bovine serum albumin on phototransformations of hematoporphyrin derivative in aquaeous medium: Absorption and EPR spectroscopy study","authors":"A. Marsalka, A. Kalnaityte, T. Biekša, S. Bagdonas","doi":"10.3952/physics.v62i1.4698","DOIUrl":"https://doi.org/10.3952/physics.v62i1.4698","url":null,"abstract":"There is a constant interest to increase the efficacy of photosensitized therapy by combining it with other modalities in order to boost the oxidative stress in tumour tissues, and L-ascorbic acid (AscA) could serve as a potential candidate. The photoinduced transformations of a hematoporphyrin-type photosensitizer (HpDiA) were chosen as a model system to monitor the effects of AscA on oxygen-dependent photoreactions in aqueous model solutions of different pH. Additional data on the role of the ascorbate radical in photoreactions initiated by HpDiA, as well as on the mutual activity in samples containing bovine serum albumin (BSA), including participation in Type I reactions, were obtained performing electron paramagnetic resonance (EPR) spectroscopy measurements, done on the mixed aqueous solutions poured into capillary tubes of a carefully selected diameter, both in the dark and under illumination with a laser beam in the absence of additional trapping molecules. A strong interaction between BSA and porphyrins was determined as a main factor in the observed photoreactions, not only boosting the photooxidation and photoreduction pathways, but also leading to the enhanced photoactivity in combination with AscA, especially, in the acidic medium.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44674810","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

Interpretation of the anomalous groundwater chemistry and 234u/238u activity ratio disequilibrium in the northern part of the baltic region 波罗的海地区北部地下水化学异常和234u/238u活度比不平衡的解释

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-01-17 DOI: 10.3952/physics.v62i1.4645

R. Mokrik, V. Samalavičius

{"title":"Interpretation of the anomalous groundwater chemistry and 234u/238u activity ratio disequilibrium in the northern part of the baltic region","authors":"R. Mokrik, V. Samalavičius","doi":"10.3952/physics.v62i1.4645","DOIUrl":"https://doi.org/10.3952/physics.v62i1.4645","url":null,"abstract":"The anomalous isotope-hydrogeochemistry phenomena in the groundwater of Estonian Cambrian-Vendian (Ediacaran) and Ordovician-Cambrian aquifer systems were formed in the Late-Middle Pleistocene. In the periglacial environment, in northern and northwestern Estonia, these aquifer systems with fracture porose crystalline basement are connected to hydraulically joint unit characterized by high radioactivity groundwater. A significant alteration of groundwater occurred by series of isotope and chemistry facies fractionation. In this study, uranium isotopes activity ratio (234U/238U), 4He content, isotope-hydrogeochemistry and adjusted 14C ages are coupled for a new prospect of the estimation of northern Baltic Basin groundwater evolution. Analyzing radiocarbon and 4He groundwater residence time results and uranium isotope activity ratio distribution suggests a prolonged periglacial environment in which groundwater evolved. Stable isotope ratios of δ18O and δ2H correlation and hydrochemical composition changes support the cryogenic origin of groundwater. Pleistocene glaciations cyclically affect groundwater in multiple ways: permafrost isotope-geochemistry partitioning; periodically changing reversed flow directions of recharge and discharge areas; oscillations of the sea, river system, and periglacial lakes level, surface and sub-permafrost water mixing via taliks and fractured basement rocks. These processes lead to forming the sequence of isotope-hydrogeochemistry types and specific zoning; in general, two separate groundwater fractions – brackish in the lower part and freshened above. An extensive groundwater exploitation on the northern coast sites influenced a sharp dysfunction in the groundwater body, destabilizing the natural equilibrium state formed in the Holocene and Pleistocene.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":"1 1","pages":""},"PeriodicalIF":0.6,"publicationDate":"2022-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70032707","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

Autoencoder-aided analysis of low-dimensional Hilbert spaces 低维希尔伯特空间的自编码器辅助分析

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-01-03 DOI: 10.3952/physics.v61i4.4639

G. Žlabys, M. Račiūnas, E. Anisimovas

引用次数: 0

Numerical model of end-pumped Yb:YAG double-pass laser amplifier experimentally validated at 129 W output power 实验验证了端泵浦Yb:YAG双通激光放大器在129w输出功率下的数值模型

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-01-03 DOI: 10.3952/physics.v61i4.4641

L. Veselis, R. Burokas, A. Michailovas

引用次数: 0

Synthesis and characterization of iridium-doped multi-walled carbon nanotubes 铱掺杂多壁碳纳米管的合成与表征

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2022-01-03 DOI: 10.3952/physics.v61i4.4643

E. Jakubovskij, A. Selskis, I. Ignatjev, G. Stalnionis, V. Šablinskas

引用次数: 0

Optical properties of powder and ceramics of aluminium oxynitride obtained by self-propagating high-temperature synthesis 自蔓延高温合成氧氮化铝粉末和陶瓷的光学性能

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2021-10-11 DOI: 10.3952/physics.v61i3.4516

T. Akopdzhanyan, A. A. Kondakov, S. Rupasov, A. Kozlova, V. Pankratov

引用次数: 1

Efficiency calibration of high-purity germanium detector using Monte Carlo simulations including coincidence-summing corrections: volume source case 使用蒙特卡罗模拟包括重合求和校正的高纯度锗探测器的效率校准：体积源情况

IF 0.6 4区物理与天体物理

Lithuanian Journal of Physics Pub Date : 2021-04-12 DOI: 10.3952/PHYSICS.V61I1.4408

M. Konstantinova, D. Germanas, A. Gudelis, A. Plukis

{"title":"Efficiency calibration of high-purity germanium detector using Monte Carlo simulations including coincidence-summing corrections: volume source case","authors":"M. Konstantinova, D. Germanas, A. Gudelis, A. Plukis","doi":"10.3952/PHYSICS.V61I1.4408","DOIUrl":"https://doi.org/10.3952/PHYSICS.V61I1.4408","url":null,"abstract":"The gamma-ray spectrometry by the instrumentality of Ge detectors is used for the detection of low activity environmental samples of different geometry (soil samples, air filters with aerosols, milk powder, etc.). Such measurements require separate calibration of the detector. The high purity germanium (HPGe) gamma-ray spectrometer of GC2520 series was used for experiments. For the efficiency calibration, three cylindrical containers filled with different 60Co water solution levels were used, and the gamma-ray coincidence summing was modelled using MCNP6. The dimensions of the pure germanium crystal, provided by Canberra, were used for the simulations. The true coincidence summing takes place when two or more gamma quanta, which are emitted in a cascade from an excited nucleus, are detected within the resolving time of the detector. However, there is often a mismatch between the simulated and experimental efficiencies. The experimentally obtained and modelled spectra were compared: a good consistency of experimental and modelled results allows investigating the volume sources. During the simulation it was found that the factors affecting the accuracy of modelling are the thickness of the dead layer, crystal dimensions and the thickness of the Al detector cap. The analysis allows measuring the radionuclides activity concentration of samples placed in the containers with different filling heights having only standard shape calibration sources. The obtained accuracy is sufficient to fulfil criteria of 5–10% for such type of simulation to be applied for measurements of real samples in standard BURK-60 containers of various sample filling heights.","PeriodicalId":18144,"journal":{"name":"Lithuanian Journal of Physics","volume":" ","pages":""},"PeriodicalIF":0.6,"publicationDate":"2021-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49458663","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