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To meet the future emissions goals, the energy systems need to be decarbonized. As much of the energy use originates from urban areas, their role will be of key importance in this context. One strategy for decarbonization is to use large-scale variable renewable electricity schemes, but these include several challenges, notably the issue of supply and demand mismatch. Therefore, a mix of technologies may be needed to achieve ambitious decarbonization targets in cities. The aim of this doctoral thesis is to develop solutions for city-level energy system transition. For this purpose, a dynamic energy system model for Helsinki city is used to ana-lyze a range of scenarios for a low-carbon future. Renewable energy, in particular wind power, was chosen here as the key supply technology. As northern cities are heat-dominated, the heat-ing sector was included in the analysis by using power-to-heat and heat pump schemes in par-allel to power production. To meet short peak heat demand conditions, separate bio-boilers were also considered. Such schemes provided deep decarbonization possibilities. In the Hel-sinki case, the use of fossil fuels could be reduced even up to 70% through the coupling of wind power with curtailment and heat pumps. Though the above type of sectoral coupling to heating helps to integrate large amounts of intermittent renewable power, the role of the exog-enous power market proved to be important for wind power integration. For Helsinki, for ex-ample, with a wind power capacity of 1500 MW corresponding to 62% of the annual electricity demand, 89% of the wind electricity could be used locally in the different sectors, but the rest needs to be coupled to the exogenous market due to the mismatch and plant limitations. In-corporationg demand-side measures, e.g., building energy efficiency, could save 6%-13% in the annual system costs. Other alternatives such as sustainable gas were also investigated. The results of this thesis indicate that there are severa

The fabrication of novel electronic devices requires new kinds of materials. The use of carbon nanotubes (CNTs) in various applications has already been demonstrated and therefore the CNTs are also important carbon materials in addition to graphene and fullerenes. Because the electronic properties of individual CNTs depend on their atomic structures, the individual CNTs are not possibly the best choice for building new electronics. Instead, the new devices could be made using thin films or networks of CNTs. The CNT thin films are transparent, flexible, and conduct electricity. Hence, the CNT thin films are expected to be utilised in a remarkable amount of applications including transistors, touch screens, and solar cells. However, a significant challenge related to the CNT thin films is making a film with both high conductivity and transparency simultaneously. Several methods to improve the conductivity of CNT networks have been studied experimentally. The goal of this thesis is to investigate a few methods to increase the conductivity of CNT networks by using density functional theory combined with the standard Green's function electron transport calculations. In particular, the conductance of junctions of CNTs is examined since the CNT junctions mainly determine the conductivity of the whole network. Two different approaches to improve the electrical conductivity of CNT networks are studied. The conductivity can be enhanced by depositing group 6 transition metal (TM) atoms on the CNT networks because the TM atoms are able to link the CNTs. The four-terminal electron transport calculations show that Cr, Mo, and W linker atoms enhance the conductances of the CNT junctions in a similar way. The increase in the conductance is related to the strong hybridisation between the carbon and TM atom orbitals. The second approach is based on functionalising the CNTs with molecules. The interaction of AuCl4 molecules with CNTs leads to a p-type doping effect. In addition, the d, Uusien elektronisten laitteiden valmistus vaatii uudenlaisia materiaaleja. Hiilinanoputkien käyttäminen useissa sovelluksissa on jo demonstroitu, ja siksi hiilinanoputket ovat myös tärkeitä hiilimateriaaleja grafeenin ja fulleriinien lisäksi. Koska yksittäisten hiilinanoputkien elektroniset ominaisuudet riippuvat hiilinanoputkien atomirakenteesta, yksittäiset hiilinanoputket eivät mahdollisesti ole paras valinta uuden elektroniikan rakentamista varten. Sen sijaan uusia laitteita voitaisiin valmistaa käyttäen hiilinanoputkiohutkalvoja tai -verkkoja. Hiilinanoputkiohutkalvot ovat läpinäkyviä, taipuisia ja johtavat sähköä. Siksi hiilinanoputkiohutkalvoja odotetaan hyödynnettävän merkittävässä määrässä sovelluksia mm. transistoreissa, kosketusnäytöissä ja aurinkokennoissa. Merkittävä hiilinanoputkiohutkalvoihin liittyvä haaste on kuitenkin valmistaa kalvo, jolla on samanaikaisesti sekä suuri johtavuus että läpinäkyvyys. Useita menetelmiä hiilinanoputkiverkkojen johtavuuden parantamiseen on tutkittu kokeellisesti. Tämän tutkielman tavoite on selvittää muutamaa menetelmää hiilinanoputkiverkkojen johtavuuden parantamista varten käyttäen tiheysfunktionaaliteoriaa yhdistettynä tavallisiin Greenin funktio -elektronikuljetuslaskuihin. Erityisesti hiilinanoputkiliitosten johtavuutta tutkitaan, koska hiilinanoputkiliitokset pääasiassa määrittävät koko verkon johtavuuden. Kahta erilaista lähestymistapaa hiilinanoputkiverkkojen sähkönjohtavuuden parantamiseksi tutkitaan. Johtavuutta voidaan kasvattaa pinnoittamalla hiilinanoputkiverkot ryhmän 6 transitiometalliatomeilla, koska transitiometalliatomit pystyvät yhdistämään hiilinanoputket. Neljän terminaalin elektronikuljetuslaskut osoittavat, että Cr-, Mo- ja W-linkkeriatomit voimistavat hiilinanoputkiliitosten johtavuutta samalla tavalla. Johtavuuden kasvu liittyy vahvaan hybridisaatioon hiili- ja transitiometalliatomien orbitaalien välillä. Toinen lähestymistapa perustuu hiilinanoputkien funktionalisoimiseen molekyyleillä. Vuorova

type:Journal Article, We report a recent study on photoluminescence (PL) properties of CdSe/ZnS/TOPO nanocrystals (NCs) in a planar full microcavity composed of top and bottom two metal (Ag) mirrors, and also in a similar structure but without top mirror, i.e. half-microcavity, respectively. Angular-dependencies of PL spectra and PL decay curves have been measured to investigate PL modifications due to light-matter coupling in the microcavities. Obtained results indicate that PL dynamics are drastically changed depending on the microcavity structures. In the full-microcavity, PL emission is directed at particular angles and its decay-time is shortened, both of which can be described in terms of so-called Purcell effect, i.e. the interaction between photon-modes and confined excitons in the NCs. As for the half-microcavity, anomalous PL band appears at low energy side of a main PL band associated with the confined excitons. The origin of the anomalous PL will be interpreted as due to the interaction between specific photon-modes in the half-microcavity structure and excitons associated with surface states., source:https://doi.org/10.1002/pssc.201000526

type:Journal Article, We describe our improved synthesis and optical properties of high quality type II CdTe/CdSe nanocrystals (NCs). Specifically, clear shell-thickness dependences have been observed in the absorption and photoluminescence (PL) spectra and PL decay profiles as well. The magnitude of the lowest absorption band decreases drastically with large redshift as the shell thickness increases. The origin will be discussed on the bases of the model where the spatial configuration of the lowest electron-hole pair in the NCs changes from that of type I to type II as the shell thickness increases. As for the PL lifetime of the lowest electron-hole excitations, substantial increase is observed with increasing shell thickness. This can also be understood by considering the spatial configuration; spatial overlap between electron and hole wavefunctions decreases with increasing shell thickness, thus the lifetime increases. As for the NCs with extremely thin shell (∼1 ML; 1 ML = 0.35 nm), the PL lifetime seems much longer than expected. This suggests that the thin shells seem imperfect and work rather a kind of trap sites than layers., source:https://doi.org/10.1002/pssc.200879878

type:Conference Paper, We report our recent trials examining the single-molecule three-dimensional (3D) detection of protein conformational dynamics at room temperature. Using molecular chaperones as model proteins and cadmium selenide (CdSe) semiconductor quantum dots (QDs) as nanometer-scale probes, we monitored the temporal evolution of ATP-induced conformation changes with a total internal reflection fluorescence (TIRF) microscopy imaging technique in buffer solutions. The two-dimensional (2D) degenerate nature of the emission dipoles of the QDs, due to the uniaxial wurtzite crystal structure, made it possible to capture the 3D orientation using a polarization modulation technique in real time. The temporal resolution was half the period of analyzer rotation. Although still insufficient, the obtained signals suggest possible 3D detection of specific motions, which supports the two-step conformational changes triggered by ATP attachment., 18th International Conference on Dynamical Processes in Excited States of Solids (DPC2013), August 4-9，2013, Fuzhou, China, source:https://doi.org/10.1016/j.jlumin.2014.01.059

type:Journal Article, We report on the dynamics of photoexcited carriers using picosecond luminescence measurements of GaAs/AlAs superlattices with a barrier width of 1.2 nm and a well width of 3.4 nm. The observed decay kinetics allow us to observe the tunneling-assisted radiative recombination of electrons and holes in different wells. Furthermore, introducing an enlarged well in the superlattice, we investigate the dynamics of photoexcited carriers sinking into the deeper well via vertical transport., source:http://www.aps.org, source:https://doi.org/10.1103/PhysRevB.34.9019

type:Journal Article, Photoluminescence (PL) decay time measurements at 77 and 300 K are reported from 6.1 nm GaAs single quantum well heterostructures (SQWH’s) confined by GaAs/AlAs short‐period superlattices (SPS’s) or ternary AlGaAs alloys with similar Al content, prepared by molecular beam epitaxy. The SQW PL intensity exhibits a single exponential decay with a time constant of 1.6 ns for SQWH’s confined by SPS’s and 0.3 ns for SQWH’s confined by AlGaAs alloys at 77 K. From comparison of the decay rates in both types of the sample, it is found that the radiative recombination efficiency is improved by a factor of about 6 in SPS confined SQWH’s. This higher efficiency is attributed to the improved heterointerfaces in addition to the enhanced radiative recombination rate due to the increased overlap of electron and hole wave functions in the narrow SQW., source:http://www.aip.org

type:Journal Article, The results of room-temperature fluorescence lifetime measurements are reported for the excitation of J aggregates (Js) of pseudoisocyanine chloride (PIC-Cl) prepared in potassium polyvinyl sulfate (PVS) polymer thin films, their aqueous solutions, and NaCl aqueous solutions. Variations of the microscopic morphologies of the aggregates were investigated. The results show that fluorescence decay features correlated to the morphology change. The observed fluorescence lifetime and quantum efficiency of PIC J aggregates (PIC-Js) in a NaCl aqueous solution were 310 ps and 28%, respectively. The lifetime of the fibril-shaped macroaggregates prepared in PVS thin films was below the instrumental time resolution of 5 ps, and the efficiency decreased to below 3%. The results indicate that PIC-Js prepared with PVS polymers have an increased nonradiative contribution to the excitation deactivation process. In particular, macro-Js with isolated fibril-shaped structures revealed nonradiative pathway(s) that are closely associated to the specific packaging morphology of the constituent meso-Js. The possibility of a destructive effect on the formation of cavity-polaritons is also discussed., source:https://doi.org/10.3390/ijms13055851

type:Journal Article, We have investigated reflection properties of light-matter strong coupling in a planar metal-mirror microcavity with highly concentrated PIC J-aggregates. Large vacuum Rabi-splitting ranging from 100 to 250 meV is obtained depending on the concentration of the J-aggregates. The factors for providing these large Rabi-splitting will be discussed based on its concentration dependence. We also present our recent study focused on microscopic reflection properties of the microcavity. We have improved microscope optics which enables us to measure local reflection spectra within 0.3-m-diameter area. Observation of incident-light-angle dependence becomes possible. We found existence of micrometer-scale inhomogeneity in the Rabi-splitting (e.g. ±10% in a region), which will be interpreted mainly by the spatial distribution of J’s in the active layer., source:https://doi.org/10.1016/j.phpro.2010.01.229

type:Journal Article, We report the synthesis, characterization, and photoluminescence (PL) properties of colloidal I-III-VI2 CuInS2 and CuInS2/ZnS nanocrystals (NCs). Absorption shoulder and PL bands of the NCs are located at higher energy than those of band gap energy of bulk crystals due to a quantum-confinement effect. The PL band has a relatively large Stokes-shift, broad linewidth, and long decay-time, which suggests that the PL originates from a recombination of confined-excitions associated with donor(s) and/or acceptor(s). We found that quantum yield of the PL depends strongly on the photon-energy of excitation light and that it is up to 40-50% in resonant excitation at the energy positions corresponding to the absorption shoulder. Detailed properties and possible dynamics will be described. We also present preliminary results of PL properties focused on single NCs. There exist highluminescent NCs exhibiting so-called PL blinking as similar with II-VI NCs, while the others are dark NCs. 73.21.La, 78.47.jd, 78.67.Bf, 78.67.Hc

The purpose of the study. To determine whether it is possible to use passive acoustic thermometry to measure the core temperature of human body regions. Materials and methods. Thermal acoustic radiation was measured by a multichannel acoustic thermograph with a threshold sensitivity of 0.3°С at an integration time of 10 s. A portable computer infrared thermograph with a sensitivity of 0.1°С was used to measure the superficial temperature. Results. Measurements of thermal acoustic radiation of the right hypochondrium of the study subject were carried out to obtain an integral temperature of the liver after intake of sugar. At the same time, blood glucose concentrations were measured. The glucose level increased from 4 to 8 mmol/l within an hour and a half; then it began to decline. The acoustic radiation temperature increased by 2°С with a half an hour delay after the increase in the glucose level. Model calculation showed that the liver temperature increased from 37 to 38°С. Conclusion. It was shown that passive acoustic thermometry can be used to measure the core temperature of different regions of the human body. The proposed method may be useful in the emergency medicine., Цель исследования. Установить возможность использования пассивной акустической термометрии для измерения глубинной температуры участков тела человека. Материалы и методы. Тепловое акустическое излучение измеряли многоканальным акустотермографом с пороговой чувствительностью 0,3°С при времени интегрирования 10 с. Для измерения поверхностной температуры использовали портативный компьютерный инфракрасный термограф с чувствительностью 0,1°С. Результаты исследования. Измерения теплового акустического излучения правого подреберья испытуемого провели, чтобы получить интегральную температуру печени после приема испытуемым сахара. Одновременно проводили измерения концентрации глюкозы в крови. В течение полутора часов содержание глюкозы выросло от 4 до 8 ммоль/л, после чего начало снижаться. С задержкой в полчаса после увеличения концентрации глюкозы измеряемая акустояркостная температура увеличилась на 2°С. Модельный расчет показал, что температура печени при этом увеличилась с 37 до 38°С. Заключение. Показали, что пассивную акустическую термометрию можно использовать для измерения глубинной температуры участков тела человека. Предложенный метод может быть востребован в медицине критических состояний.

type:Journal Article, Transient luminous events above thunderstorms such as sprites, halos, and elves require large electric fields in the lower ionosphere. Yet very few in situ measurements in this region have been successfully accomplished, since it is typically too low in altitude for rockets and satellites and too high for balloons. In this article, we present some rare examples of lightning‐driven electric field changes obtained at 75–130 km altitude during a sounding rocket flight from Wallops Island, Virginia, in 1995. We summarize these electric field changes and present a few detailed case studies. Our measurements are compared directly to a 2D numerical model of lightning‐driven electromagnetic fields in the middle and upper atmosphere. We find that the in situ electric field changes are smaller than predicted by the model, and the amplitudes of these fields are insufficient for elve production when extrapolated to a 100 kA peak current stroke. This disagreement could be due to lightning‐induced ionospheric conductivity enhancement, or it might be evidence of flaws in the electromagnetic pulse mechanism for elves.

type:Journal Article, In this work, lipase from Candida rugosa was immobilized onto chitosan/graphene oxide beads. This was to provide an enzyme-immobilizing carrier with excellent enzyme immobilization activity for an enzyme group requiring hydrophilicity on the immobilizing carrier. In addition, this work involved a process for the preparation of an enzymatically active product insoluble in a reaction medium consisting of lauric acid and oleyl alcohol as reactants and hexane as a solvent. This product enabled the stability of the enzyme under the working conditions and allowed the enzyme to be readily isolated from the support. In particular, this meant that an enzymatic reaction could be stopped by the simple mechanical separation of the “insoluble” enzyme from the reaction medium. Chitosan was incorporated with graphene oxide because the latter was able to enhance the physical strength of the chitosan beads by its superior mechanical integrity and low thermal conductivity. The X-ray diffraction pattern showed that the graphene oxide was successfully embedded within the structure of the chitosan. Further, the lipase incorporation on the beads was confirmed by a thermo-gravimetric analysis. The lipase immobilization on the beads involved the functionalization with coupling agents, N-hydroxysulfosuccinimide sodium (NHS) and 1-ethyl-(3-dimethylaminopropyl) carbodiimide (EDC), and it possessed a high enzyme activity of 64 U. The overall esterification conversion of the prepared product was 78% at 60°C, and it attained conversions of 98% and 88% with commercially available lipozyme and novozyme, respectively, under similar experimental conditions.

type:Journal Article, We present a study of strong exciton-photon coupling and its dependence on incident light polarization in a metal-metal mirror microcavity containing PIC J-aggregates. Rabi-splitting energies between upper and lower polariton branches are estimated as 94 meV and 69 meV for s- and p-polarized incident light, respectively. These large values are due to large oscillator strength of Frenkel excitons in the PIC J-aggregates and strong confinement of light attributed to the metallic microcavity as well. As for the effective thickness of the active layer for s-polarized light, a good agreement is obtained between Lfiteff = 201 nm deduced from the experimental data and Lcalceff = 207 nm calculated from the summation of the measured thickness of active layer with the estimated penetration depths into silver mirrors. We also discuss the difference in the polarization dependences of Rabi-splitting energy, quantitatively. It is concluded that the polarization dependence is mainly due to an alignment of the J-aggregates in the active layer and is not affected so much by anisotropy of the penetration depths into the silver mirrors., source:https://doi.org/10.1002/pssc.200879879

We present measurements of the charge-exchange reaction rate between neutral sodium (Na) and ionized calcium (Ca+) in a hybrid atom-ion trap, which is comprised of a Na magneto-optical trap concentric with a linear Paul trap. Once the Na and Ca+ are co-trapped, the reaction rate is measured by continuously quenching the reaction product Na+ from the ion trap, and then destructively measuring the decay of the remaining ion population. The reactants’ electronic state and temperature are experimentally controlled, allowing us to determine the four individual reaction- rates between Na[S or P] and Ca+[S or D] at different collision energies. With the exception of the largest reaction-rate channel (Na[S] + Ca+[D]), our rates agree with classical Langevin rate limit. We have also found evidence of reactant collision-energy thresholds associated with two of the four entrance-channels.

Purpose. The first portions of the emerging є- paramagnetic and а '- ferromagnetic martensite under uniaxial compression plastic deformation moderately unstable austenite chromium-nickel X12CrNi15-16 steel experimentally fix. Methodology. Dependence of the magnetic susceptibility of the steel from the degree of deformation K and amount of а '- martensite deformation sensitive magnetometric method is found. This method influence of the magnetization of paramagnetic austenite into account. Neglecting the magnetization of paramagnetic austenite leads to significant errors in determining the very low number of а- phase, for example, the error is more than 1000 % when the content of а -phase 0.005 %, 80 % - at 0.1 %, and only in the presence of 2.5 ... 3.0 % error reaches about 3 %. Findings. In X14CrNi17-18 steel (stable austenite) during plastic deformation by compression (K = 0...67 %) the paramagnetic susceptibility increased by 4 % revealed. In this steel transformation у ^ а ' is not found. In X12CrNi15-16 steel with unstable austenite moderately depending on the degree of deformation three regions of phase transformations found. The first region of deformation: while increasing the plastic deformation (K = 0 ... 26 %) increase in the magnetic state of the austenite у ^ у ' and increase the paramagnetic susceptibility of austenite by 8 % to maximum value z ' / aX takes place. The second region: with increasing deformation (K = 26.5 ... 44 %) in the paramagnetic austenite matrix formed the first portions of the paramagnetic є- and ferromagnetic а ’ martensite deformation (у/тх ^ є + у' + а '). In this region, the amount of deformation occurring а'-martensite Ра = 0.01 ... 0.025 % is found. The third region: with increasing deformation (K = 49 ... 70 %) is transformed paramagnetic phase є and у' to maximum paramagnetic state у 'max austenite (є + у '^ у 'max, у 'max а ' ). Further accumulation of the amount of а -martensite (Ра = 0.03 ... 0.11 %) takes place. Origina, Цель. Экспериментально зафиксировать первые порции зарождающихся парамагнитного є- и ферромагнитного а - мартенситов при одноосной пластической деформации сжатием умеренно нестабильного аустенита хромоникелевой стали 12Х15Н16. Методика. Для нахождения зависимости магнитной восприимчивости аустенизированной исследуемой стали от степени деформации К и определения весьма низких содержаний зарождающегося а - мартенсита деформации использовался чувствительный магнитометрический метод, учитывающий влияние намагниченности парамагнитного аустенита. Неучет намагниченности парамагнитного аустенита приводит к значительным погрешностям определения весьма низкого количества а-фазы, например, ошибка составляет более 1000 % при содержании а-фазы 0.005 %, 80 % - при 0.1 % и лишь при наличии 2.5 ... 3.0 % ошибка достигает ~3 %. Результаты. Установлено, что в стали 14Х17Н18 со стабильным аустенитом при пластической деформации сжатием (К= 0 .6 7 %) парамагнитная восприимчивость увеличилась на 4 % и при этом не обнаружено у-^а' превращение. В стали 12Х15Н16 с умеренно нестабильным аустенитом выявлено в зависимости от степени относительной деформации К три области: 1 - в процессе увеличения пластической деформации (К = 0 .2 6 %) возрастает магнитное состояние аустенита у -^ у ', которое описывается увеличением парамагнитной восприимчивости аустенита на 8 % до постоянного максимального значения %max ; 2 - при последующем увеличении деформации (К= 26.5 ... 44 %) в полученной парамагнитной аустенитной матрице зарождаются первые порции парамагнитного є- и ферромагнитного а-мартенситов деформации (у'max ^ є + у' + а '), в этой области количество возникающего o'-мартенсита зафиксировано Ра = 0.01 ... 0.025 %; 3 - при дальнейшей деформации (К= 4 9 .7 0 %) происходит превращение парамагнитных фаз єи у в исходное максимальное парамагнитное состояние у' max аустенита (є+ у '^ у ' max, у/тах ^ а ') и дальнейшее накопление количества а - мартенсита (Ра = 0.03 ... 0.11 %). Научная новизна. Предложен, Мета. Експериментально зафіксувати перші порції парамагнітного є- і феромагнітного а - мартенситів, які зароджуються при одновісній пластичній деформації стисненням помірно нестабільного аустеніту хромонікелевої сталі 12Х15Н16. Методика. Для знаходження залежності магнітної сприйнятливості аустенізованої досліджуваної сталі від ступеня деформації К і визначення дуже низьких вмістів а - мартенситу деформації, який зароджується, використовувався чутливий магнітометричний метод, що враховує вплив намагніченості парамагнітного аустеніту. Неврахування намагніченості парамагнітного аустеніту призводить до значних похибок визначення низької кількості а-фази, наприклад, похибка складає більше 1000 % при вмісті а-фази 0.005 %, 80 % - при 0.1 % і лише за наявності 2.5 ... 3.0 % похибка досягає ~ 3 %. Результати. Встановлено, що в сталі 14Х17Н18 зі стабільним аустенітом при пластичній деформації стисненням (К= 0...67 %) парамагнітна сприйнятливість збільшилась на 4 % і при цьому не виявлено у ^ а ' перетворення. У сталі 12Х15Н16 з помірно нестабільним аустенітом виявлено залежно від ступеня відносної деформації К три області: 1 - в процесі збільшення пластичної деформації (К = 0 ... 26%) зростає магнітний стан аустеніту у - ^ у \ який описується збільшенням парамагнітної сприйнятливості аустеніту на 8 % до постійного максимального значення ; 2 - при подальшому збільшенні деформації (К =26.5 ...44 %) в отриманій парамагнітній аустенітній матриці зароджуються перші порції парамагнітного є- і феромагнітного а'- мартенситів деформації (у/шах^ £ + у /+ а /), у цій області зафіксовано кількість а'-мартенситу Р а = 0.01 ... 0.025% що виникає; 3 - при подальшій деформації (К= 49...70 %) відбувається перетворення парамагнітних фаз є і у' у вихідний максимальний парамагнітний стан у/шах аустеніту (є +у'-^у/шах, у/тах ^ а ') і подальше накопичення кількості а '- мартенситу (Ра = 0.03 ... 0.11%). Наукова новизна. Запропоновано фізичну модель зародження перших порцій є- і а '- мартенситів

Purpose. To improve durability and trouble-free operation of electric furnaces it is required to ensure reliable operation of their most important element - heater. As a material for heating elements heat-resistant steels and alloys shall be used. Extensive application among them find Fe-Cr-Al alloys. To increase durability of the heaters it is required to improve surface quality of the heaters and, consequently, technological and service properties. Methodology. The article describes the main factors which affect the process of formation of dense oxide films, analyzed defects that are observed on the surface of the wire, used for manufacture of heating elements of electric resistance furnaces. It shows that ensuring formation of dense and adherent scale of protective oxide films such as spinels FeO-(AhO3, &2O3) on metal surface, plays an important role in improvement of corrosion resistance. Findings. During the study of the surface layer of wires Х15Ю5, Х20Н80 it was found that on the surface of the metal there were defects formed during the factory production of the wires. The article presents a comparative analysis of the surface of steel wire 03Х23Ю5Т before vapor-plasma discharge treatment and after the treatment which lasted for 30 seconds and 6 minutes. Originality. Researchers have extensively studied the effect of reactive alloying elements Ca, Ce, La, Y, on the properties of protective oxide films: adhesive capasity of the oxide layer, its plasticity and growth rate. However, the relation between quality of the surface of the wire for the heaters and technological, operational properties has not been established. Practical significance. Service life of a furnace before the overhaul is directly connected with the service life of heating elements. Consequently, increasing the service life of the heater is an important issue, both from technical and economical points of view. Necessity for use of joint integrated modification with additional vapor-plasma, Цель. Для повышения долговечности и безотказной работы электрических печей сопротивления требуется обеспечить надежную работу его наиболее важного элемента - нагревателя. В качестве материала для элементов сопротивления используются жаростойкие стали и сплавы, широкое применение среди них находят железохромалюминиевые сплавы: фехрали и хромали. Для повышения срока службы нагревателей необходимо повышение качества поверхности нагревателей и, следовательно, технологических и служебных свойств. Методика. В статье рассмотрены основные факторы, влияющие на процесс образования плотных окисных пленок, проанализированы дефекты, которые наблюдаются на поверхности проволоки, применяемой для изготовления нагревательных элементов электрических печей сопротивления. Показано, что обеспечение образования плотного, прочно сцепленного слоя защитных окисных пленок типа шпинелей FeO-(AhO3, СГ2О3) на поверхности металла, играет большую роль в повышении коррозионной стойкости. Результаты. При исследовании поверхностного слоя проволоки марок Х15Ю5, Х20Н80 установлено, что на поверхности металла присутствуют дефекты, образовавшиеся в процессе производства проволоки в заводских условиях. В статье проводится сравнительный анализ поверхности проволоки из стали 03Х23Ю5Т до обработки пароплазменным разрядом и после обработки в течение 30 секунд и 6 минут. Научная новизна. Исследователями широко изучалось влияние реактивных легирующих элементов Ca, Ce, La, Y, на свойства защитных оксидных пленок: адгезионную способность оксидного слоя, его пластичность и скорость роста. Однако взаимосвязь между качеством поверхности проволоки для нагревателей и технологическими, эксплуатационными свойства не была установлена. Практическая значимость. Срок службы печи до капитального ремонта напрямую связан со сроком службы нагревательных элементов, следовательно, увеличение срока службы нагревателя является важной задачей, как с технической, так и с экономической точки зрения. Выявлена и обоснована необходимост, Мета. Для підвищення довговічності і безвідмовної роботи електричних печей опору потрібно забезпечити надійну роботу його найбільш важливого елемента - нагрівача. В якості матеріалу для елементів опору використовуються жаростійкі сталі і сплави, широке застосування серед них знаходять залізохромалюмінієві сплави: фехралі і хромалі. Для підвищення терміну служби нагрівачів необхідно підвищення якості поверхні нагрівачів і, отже, технологічних і службових властивостей. Методика. У статті розглянуті основні фактори, що впливають на процес утворення щільних окисних плівок, проаналізовано дефекти, які спостерігаються на поверхні дроту, що застосовується для виготовлення нагрівальних елементів електричних печей опору. Показано, що забезпечення утворення щільного, міцно зчепленого шару захисних окисних плівок типу шпінелей FeO-(AhO3, &2O3) на поверхні металу, грає велику роль у підвищенні корозійної стійкості. Результати. При дослідженні поверхневого шару дроту марок Х15Ю5, Х20Н80 встановлено, що на поверхні металу присутні дефекти, що утворилися в процесі виробництва дроту в заводських умовах. У статті проводиться порівняльний аналіз поверхні дроту зі сталі 03Х23Ю5Т до обробки пароплазмовим розрядом і після обробки протягом 30 секунд і 6 хвилин. Наукова новизна. Науковцями широко вивчався вплив реактивних легуючих елементів Ca, Ce, La, Y, на властивості захисних оксидних плівок: адгезійну здатність оксидного шару, його пластичність і швидкість росту. Однак взаємозв'язок між якістю поверхні дроту для нагрівачів і технологічними, експлуатаційними властивостями не був встановлений. Практична значимість. Термін служби печі до капітального ремонту безпосередньо пов'язаний з терміном служби нагрівальних елементів, отже, збільшення терміну служби нагрівача є важливим завданням, як з технічної, так і з економічної точки зору. Виявлено та обґрунтовано необхідність використання спільного комплексне модифікування з додатковою обробкою ППР для підвищення технологічних та експлуат

Purpose. The aim of this study is to develop and to test management system TCT, which allows to get the required parameters of the diffusion layer - saturating concentration of the element C and the gradient of its distribution, as well as the thickness of the layer B to products of critical appointment. Methodology. As the material for research is selected the steel of the type 14ХГСН2МА which was influenced bu carburizing in solid carburizer at 1300 K. In order to study the kinetics of diffusion saturation (cementation) was used differential dilatometer. Findings. The laws of change of the linear dimensions of the sample tube differential dilatometer during the entire cycle of carburizing steel 14ХГСН2МА. The use of standard hollow instead of a solid, greatly improving the accuracy of fixing the beginning of diffusion saturation, which can be explained by more rapid heating of the hollow standard. This shown that the constructed dilatometric curves allow to identify and prevent saturation directly in the process of such undesirable processes as decarburization and sudden cessation of diffusion saturation with insufficient activity saturating the atmosphere. After reaching the temperature of carburizing steel 14ХГСН2МА (1300 K) there was an increase over time elongated tubular sample. These results confirmed the theoretical calculations of the length of the tubular sample based on the data dependence of the lattice parameter of austenite on the content of carbon in it. Also, using the results of chemical analysis and metallographic analysis supersaturation prototypes carbon steel 14ХГСН2МА and ways saturation mode to obtain the required parameters of cemented layer. Originality. For the first time to monitor and control the process suggested the use of steel TCT differential dilatometer. We give the design features, the operating principle of the device and its proper use as an example of carburizing steel 14ХГСН2МА. Practical value. It is shown that by using diffe, Цель. Целью данной работы была разработка и испытание системы управления ХТО, которая позволяет гарантированно получать необходимые параметры диффузионного слоя - концентрацию насыщающего элемента С и градиент его распределения, а также толщину слоя B для изделий ответственного назначения. Методика. Материалом для исследований выбрана сталь марки 14ХГСН2МА, которую подвергали цементации в твёрдом карбюризаторе при температуре 1300 К. Для исследования кинетики диффузионного насыщения (цементации) был использован дифференциальный дилатометр. Результаты. Установлены закономерности изменения линейных размеров трубчатого образца дифференциального дилатометра в процессе всего периода цементации стали 14ХГСН2МА. Использование пустотелого эталона вместо сплошного позволило значительно повысить точность фиксации начала процесса диффузионного насыщения, что можно объяснить более ускоренным прогревом пустотелого эталона. В работе показано, что построенные дилатометричекие кривые дают возможность определить и предотвратить непосредственно в процессе насыщения такие нежелательные процессы, как обезуглероживание и внезапное прекращение диффузионного насыщения при недостаточной активности насыщающей атмосферы. После выхода на температуру цементации стали 14ХГСН2МА (1300 К) наблюдалось удлинение трубчатого образца. Указанные результаты подтверждены теоретическими расчетами длины трубчатого образца на основании данных зависимости параметра решетки аустенита от содержания в нём углерода. Также, с помощью результатов метоллографического и химического анализа установлено пересыщение опытных образцов стали 14ХГСН2МА углеродом и предложены режимы насыщения для получения требуемых параметров цементированного слоя. Научная новизна. Впервые для контроля и управления процесса ХТО стали предложено использование дифференциального дилатометра. В работе указаны особенности конструкции, принцип работы прибора и правила его эксплуатации на примере цементации стали 14ХГСН2МА. Практическая значимост, Мета. Метою даної роботи була розробка та випробування системи керування ХТО, яка дозволяє гарантовано отримувати необхідні параметри дифузійного шару - концентрацію насичуваного елементу С і градієнт його розподілу, а також товщину шару B для виробів відповідального призначення. Методика. Матеріалом для досліджень вибрана сталь марки 14ХГСН2МА, яку піддавали цементації у твердому карбюризаторі при температурі 1300 К. Для дослідження кінетики дифузійного насичення (цементації) був використаний диференційний дилатометр. Результати Встановлено закономірності зміни лінійних розмірів трубчастого зразка диференційного дилатометру в процесі всього періоду цементації сталі 14ХГСН2МА. Використання пустотілого еталону замість суцільного дозволило значно підвищити точність фіксації початку процесу дифузійного насичення, що можна пояснити більш прискореним перегріванням пустотілого еталону. У роботі показано, що побудовані дилатометричні криві дають можливість визначити і запобігти безпосередньо в процесі насичення таким небажаним процесам, як зневуглецювання і раптове припинення дифузійного насичення при недостатній активності насичуючої атмосфери. Після виходу на температуру цементації сталі 14ХГСН2МА (1300 К) спостерігалося видовження трубчастого зразка. Зазначені результати підтверджені теоретичними розрахунками довжини трубчастого зразка на підставі даних залежності параметра гратки аустеніту від вмісту в ньому вуглецю. Також, за допомогою результатів металографічного та хімічного аналізу встановлено пересичення дослідних зразків сталі 14ХГСН2МА вуглецем та запропоновано режими насичення для отримання необхідних параметрів цементованого шару. Наукова новизна. Вперше для контролю та керування процесу ХТО сталі запропоновано використання диференціального дилатометру. У роботі вказані особливості конструкції, принцип роботи приладу та правила його експлуатації на прикладі цементації сталі 14ХГСН2МА. Практична значимість. Показано, що за допомогою диференційного дилатометру і

An intrinsic issue of large-array beamforming and signal processing in random-inhomogeneous environments is known to be considerable degradation of signal coherence in space domain. Such a scenario arises in many applications, and array operations in underwater sound channels with emphasis on long-range sound propagation is one of the most typical cases. Another key issue is here the multimode propagation of the desired signal (and, generally, noise interference) so the spatial spectrum of the received field consists of numerous harmonics even for a single point source. In this paper, our focus is to demonstrate numerically the multimode signal coherence degradation at the large-array input, both for horizontal and vertical arrays in an underwater channel, and to predict the coherence effects on the output performance, array beampattern and gain included. The vertical array operation is emphasized to be the most interesting problem here due to the specific features of ambient noise in real oceanic channels. An essential conclusion concerns the fact that not only the signal coherence but signal localization in mode domain as is compared with the ambient noise affect together the array output performance.

In this paper we show experimental data of antibody adsorption isotherms onto polystyrene surfaces. These values corroborate the important role played by both the electrostatic and the hydrophobic interactions in protein adsorption processes. To do that, we have worked with a well-known protein (IgG) and its F(ab')2 fragment. Both macromolecules differ in isoelectric points and molecular weights. The first factor allows us to study the influence of the electrostatic forces that come into play if the adsorption isotherms are carried out at different pHs in low ionic strength media. In addition, we have used four different colloidal polymer particles (latex) in order to analyze the importance of the hydrophobic driving force for protein adsorption. Our results clearly indicate that: (i) the most hydrophobic latex adsorbs the maximum amounts of both antibody molecules, and (ii) the highest affinity shown by antibodies for sorbent surfaces is found when both have opposite sign of charge, that is, under favourable electrostatic interaction conditions. On the other hand, when adsorbing IgG and F(ab')2 as a function of pH at low ionic strength media, a maximum amount of adsorbed antibodies is observed near the isoelectric point of the protein-latex complex. Finally, we have also quantified the adsorption affinity using a thermodynamic equation that allows us to calculate the standard free energy for the transfer of one mole of protein from bulk water to the surface.

Surfactants are essential in the isolation of integral membrane biomolecules from biological membranes of different microorganisms. Our objective is the isolation of the major outer membrane protein (MOMP) of Chlamydia trachomatis, to use it in the preferential and specific detection of immunoglobulins. We have improved a method using an alkylglycoside surfactant, n-Octyl-b-D-thioglucoside (OTG), which is a non-ionic detergent used in membrane solubilization due to its "weak" action preserving the biological and functional properties of solubilized biomolecules. Different solubilization conditions, such as surfactant and salt concentrations, temperature and the presence of additive (di-thiothreitol (DTT)), were tested. To know the influence of the parameters previously indicated on the micellar properties and the solubilizing ability of the surfactant, we have studied the micellization process of OTG under several conditions by using static fluorescence measurements. MOMP was isolated by a simplified method consisting of a two-step extraction using OTG and DTT with an optimization of the experimental conditions. In this way, MOMP turns out to be separated from other biomolecules (i.e., lipopolysaccharides) in order to avoid immunological cross-reactions among the different chlamydial species. Furthermore, gel electrophoresis experiments showed monomeric MOMP without multi-aggregation, even after removing DTT and OTG molecules by dialysis of the OTG-DTT soluble fraction. The isolated protein (MOMP) is used to coat microplate wells to develop immunoenzymatic assays (ELISA). The preliminary immunological study shows the detection of specific IgG of Chlamydia trachomatis, with adequate values of the immunological parameters: sensibility and specificity. Moreover, these results show the role of surfactant molecules in the binding process of proteins to solid-liquid interface.

The Calcium Oxalate crystallization is of special interest because of its wide-spread occurrence in biomineralization processes [I-51. The formation of renal stones involves very often the precipitation of calcium oxalates. Calcium oxalate inonohydrate (COM) and calcium oxalate dihydrate (COD) are the crystalline fomls of calcium oxalate (CaOx) most commonly found in kidney stones [S]. Although thermodynamically unstable with respect to the monohydrate the COD is more commonly seen in urine [6].

Method of electromagnetic scanning tomography and holography of subsurface objects based on the solution of inverse scattering problem for the pseudopulse synthesized by multifrequency measurements of the scattered field is studied. Results of its applications to diagnostics of various subsurface inhomogeneities are demonstrated.

In the article the results of numerical and experimental studies of ultra-wideband dipole radiator and optimized CPW-to-CPS transformer (balun) are presented. Such dipole is used in GPR scanning system based on the Agilent E5071B VNA, and is located in direct proximity to object surface. Different theoretical models were developed to optimize and analyze the 50 to 100 Ohms balun with passband 1-7 GHz. The special attention was paid to matching antennas open with properties of the media under test. All numerical results were performed using CST Microwave Studio software.

It is well known that the statistical effects of long-range signal propagation in random channels generally lead to considerable degradation of both the signal coherence and the array output. In random-inhomogeneous underwater sound channels, these effects are of a primary importance if a large horizontal array is used for high-resolution operation in spatial domain. The key physical effect in such a scenario is known to be the range-dependent cross-modal coherence loss caused by multiple sound scattering by random channel inhomogeneities, both volume and windy surface ones. In this pa-per, we demonstrate numerically how and why the horizontal array output dramatically degrades if the received signal consists of a large number of partially-correlated normal modes. From the point of view of general statistical antenna theory, the results present-ed are considered to be a further development, with application to the multimode transmission channels.

type:Journal Article, Exact expressions of the Pauli exclusion operator Q in the nuclear matter calculationare presented in detail. Exact formulae are also given for the calculations of thesingle-particle-potential energy and the binding energy per nucleon with the exactQ operator. Numerical calculations of the G matrix in the lowest-order Bruecknertheory are carried out to check the reliability of the standard angle-average approximationfor the Q operator by employing the Bonn B and C NN potentials. It isobserved that the exact treatment of the operator Q brings about non-negligibleand attractive contributions to the binding energy., source:http://www.sciencedirect.com/science/journal/03759474

type:Journal Article, We report electrohydrodynamic instability in nematic liquid crystals found in Hele-Shaw cells. Due to the present cell geometry, the convective structures could be directly visualized as surface or bulk flows. An unexpected structure is observed, which is completely different from the well-known patterns in the standard cells. By using the voltage-frequency jump method, the stability of a convective structure in Hele-Shaw cells is discussed in terms of the Busse diagram., source:https://doi.org/10.1103/PhysRevE.68.042702, source:http://www.aps.org

type:Journal Article, A kind of electrohydrodynamic instability, the prewavy instability, in nematic liquid crystals is reported. The characteristic of the instability was optically investigated and discussed in comparison with some similar instabilities. Obviously the instability partially shows an isotropic feature around the nematic-isotropic transition temperature. Owing to the characteristic properties of the flow and the spatial periodicity, it should be distinguished from a previously proposed isotropic instability., source:https://doi.org/10.1103/PhysRevE.66.031705, source:http://www.aps.org

type:Journal Article, It is important to investigate condensation energy density of superconducting material, since it determines its pinning property. According to the heavy-ion irradiation, the columnar defects are introduced to the superconductor which act as the strong pinning centers, and the critical current density is enhanced by the new pinning centers. Since the number density and the size of the columnar defects can be observed, the condensation energy density is estimated by using the pinning summation theory. In the present study, we prepared Ba(Fe0.93Co0.07)2As2 (Ba-122) pnictide superconductors by self-flux method. 200 MeV Au ions were irradiated into the specimens along c-axis and the matching field was 2 T. After the irradiation, the critical current density was 6 times larger than that before the irradiation. The estimated condensation energy density is in the order of 104 J/m3 and is slightly smaller than those of cuprate superconductors. The temperature dependence is similar to that of YBa2Cu3Ox oxide superconductors, since the anisotropy parameter is small in Ba-122. Therefore, it is expected to use Ba-122 at high temperatures near the critical temperature., Superconductivity Centennial Conference 2011 - EUCAS–ISEC–ICMC, Sep 18 - 23, 2011, Hague, Netherlands, source:https://doi.org/10.1016/j.phpro.2012.06.269

type:Journal Article, Direct evidence for two different types of normal rolls and of zigzag rolls in homeotropically aligned nematic liquid crystals in a magnetic field is reported. The conventional normal rolls have the reflection symmetry in the xy plane. The instability, however, breaks the reflection symmetry y→-y on the director and then the abnormal rolls are expected to be observed. We have investigated the instability experimentally and discussed it in terms of the recent numerical results by Plaut et al. [Phys. Rev. Lett. 79, 2367 (1997)]. Due to the new instability, the abnormal zigzag rolls are also found below the Lifshitz frequency., source:http://link.aps.org/abstract/PRE/v58/p7355, source:http://www.aps.org

type:Journal Article, In this review paper, we report the characteristics of the critical current density in FeAs based superconductors which is newly discovered by Hosono group of Tokyo Institute of Technology on 2008. Since the many specimens in present stage are not single crystals, there are two kinds of critical current density observed in the specimens which are so-called local and global critical current densities. Therefore, it is necessary to evaluate both kinds of critical current densities. The history effect in which the global critical current density shows different values in increasing and decreasing magnetic field is also observed when the specimens have the local and the global critical current densities. The wire which critical current is 180 A is successfully developed with using the knowledge of abovementioned characteristics of two kinds of critical current densities and the history effect., source:https://doi.org/10.9714/psac.2012.14.2.001

type:Journal Article, We present our recent study of polarization modulating fluorescence imaging microscopy on single CdSe colloidal quantum dots (QDs) and quantum rods (QRs) adsorbed on silica glass substrates at room temperatures. Simple optical setup is introduced to provide detection of emission profiles projected on to the sample plane as well as detection of rotating excitation polarization effect. While most studies so far in structural changes in biological or amorphous systems rely on extrinsic fluorophores with linear transition dipoles, those with twofold degenerate dipoles are noteworthy due to the intrinsic advantage for 3D orientation information. Performance of modulations is also evaluated in combination with tetramethylrodamine moieties as typical linear emitters. CdSe QDs with aspect ratio of 1.3 actually reveal plane-polarized emission at room temperature and, based on maximum-likelihood analysis, are exceptionally highly oriented on silica glass substrates., source:https://doi.org/10.1016/j.phpro.2010.01.228

type:Journal Article, Versatile novel implementations in microspectroscopy are developed, which can provide angle-resolved optical spectroscopy at local sample areas almost in diffraction limit. By selecting focus position of light flux incident within the back focal plane of the objective lens radially from the position of the optical axis of the microscope with employing off-centered pinhole, we can obtain parallel beam with oblique incidence and its angle tuning at the sample surface. In this paper, we describe our specific optical setup and its practical working principle in detail. We report, as a demonstration of its performance, our latest studies on optical properties of cavity polariton states in the so-called quantum microcavity structures, which contain molecular J-aggregates of pseudoisocyanine (PIC) dye as active working materials. By using the microscope technique, we obtain a fair amount of improvement in the linewidth observation of cavity polariton spectra., source:https://doi.org/10.1155/2011/523017