Sensor for monitoring plasma parameters

A spectrally tunable VCSEL (vertical cavity surface-emitting laser) was used as part of sensing hardware for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3, 45, and 90% N2 in Ar) at pressure 0.5-70 Pa and inductive power of 100 and 300 W. The results were compared to rotational temperature derived from the N2 emission at the (0,0) transition of the C - B system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar* and N2*) that varied depending on conditions. A two-dimensional, two-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling the diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable tracking the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.Comment: Presented at the Photonics West conference, Lasers and Applications in Science and Technology, San Jose, CA, January 2004. This version gives a more detailed introduction on diode lasers as diagnostic tool for micro/nano-fabrication. A follow-up paper published in Plasma Sources Sci. Technol., v.13, 691-700 (2004) featured improvements in plasma simulatio

A comparison of Thellier-type and multispecimen paleointensity determinations on Pleistocene and historical lava flows from Lanzarote (Canary Islands, Spain)

Sixteen Miocene, Pleistocene, and historic lava flows have been sampled in Lanzarote (Canary Islands) for paleointensity analysis with both the Coe and multispecimen methods. Besides obtaining new data, the main goal of the study was the comparison of paleointensity results determined with two different techniques. Characteristic Remanent Magnetization (ChRM) directions were obtained in 15 flows, and 12 were chosen for paleointensity determination. In Thellier-type experiments, a selection of reliable paleointensity determinations (43 of 78 studied samples) was performed using sets of criteria of different stringency, trying to relate the quality of results to the strictness of the chosen criteria. Uncorrected and fraction and domain-state corrected multispecimen paleointensity results were obtained in all flows. Results with the Coe method on historical flows either agree with the expected values or show moderately lower ones, but multispecimen determinations display a large deviation from the expected result in one case. No relation can be detected between correct or anomalous results and paleointensity determination quality or rock-magnetic properties. However, results on historical flows suggest that agreement between both methods could be a good indicator of correct determinations. Comparison of results obtained with both methods on seven Pleistocene flows yields an excellent agreement in four and disagreements in three cases. Pleistocene determinations were only accepted if either results from both methods agreed or a result was based on a sufficiently large number (n>4) of individual Thellier-type determinations. In most Pleistocene flows, a VADM around 5 31022 Am2 was observed, although two flows displayed higher values around 931022 Am2.project CGL2012-32149 (Ministerio de Econom ıa y Competitividad, Spain), project 320/2011 (Ministerio de Medio Ambiente y Medio Rural y Marino, Spain) and the European Regional Development Fund (ERDF)

110 ЛЕТ М. А. СРЕСЕЛИ

On the 31 of July the University pays tribute to the memory of a famous scientist, surgeom and lecturer - Michail Andreevich Sresely. Since 1947 up to 1979 M.A. Sresely was in charge of the Operative Surgery Department and the vicerector of the 1st Leningrad Medical Institute (1950-1969 ys). His name is linked not only with the history of the Operative Surgery Department but with the history of the Institute as well. His scientific works deal with the problems of borerline forms of variability started by his scientific adviser-academician V.N. Sherkunenko. Besides, M.A. Sresely supervised doctoral dissertation (n=16) and master's theses (n = 32). For a long period of time he was a member of the Presidium of the Board of the All-union and Leningrad Anatomist's, thistologist's and Embryologist's Society. M.A. Sresely was awarded with the Order of the Patriotic war and the Order of the Red Banner. Professor M.A. Sresely is a symbol of a scientist, teacher and tutor.31 июля 2014 г. исполняется 110 лет со дня рождения известного ученого, Заслуженного деятеля науки РСФСР профессора М.А. Сресели. В статье освещены основные этапы деятельности в качестве заведующего кафедрой оперативной хирургии с 1947 по 1979 г. и проректора 1 ЛМИ им. акад. И.П. Павлова с 1950 по 1969 г. С его именем связана целая эпоха истории не только кафедры, но и института. Труды М.А. Сресели посвящены развитию учения о крайних формах изменчивости, созданного его учителем - академиком В.Н. Шевкуненко. Под его руководством защищены 16 докторских и 32 кандидатские диссертации. М.А. Сресели состоял членом Президиума Правления Всесоюзного и Ленинградского научных обществ АГЭ, избирался депутатом Петроградского районного совета народных депутатов. Он награжден орденами Отечественной войны Красного знамени. Профессор М.А. Сресели - пример ученого, педагога и воспитателя

Formation of buckling resistance in a transfemoral prosthesis

Introduction. The principles of construction of the knee joint in the transfemoral prosthesis are considered. The design of the knee joint in the transfemoral prosthesis with an original mechanism for ensuring buckling resistance in the prosthesis is proposed. Goal. Create an artificial knee joint, which provides a reliable mechanism of strut stability during walking by quickly blocking the flexion-extension of the artificial knee joint in the prosthetics for high amputations of the lower extremities when resting on the prosthesis. Materials and methods. One of the main problems that exist in the development of knee joints in a femoral prosthesis is the presence in the design of the module of a mechanism that ensures its blocking from bending when walking at the moment of support of the prosthesis in the transfer phase of a healthy limb. In the knee joints of various companies, this issue is solved in different ways. For example, some simple singleaxis knee joints are designed to lock when the disabled person is in a standing position. Walking is carried out without flexion in the knee joint. To unlock, pull the cable (transition to a sitting position). In some single-axis hinges, a locking function is applied using the weight of a disabled person. In the phase of support on a full foot, the hinge closes due to the weight load on it and opens by transferring weight to the toe. In more complex multi-axis module designs, there is a so-called geometric lock. The closure in the stance phase occurs due to the correct arrangement of the axes relative to each other. The opening occurs in the transfer phase. The object of the study. The mechanisms of the knee joint, which provide a handicapped person's resistance to buckling while walking on a transfemoral prosthesis. The subject of the study. The design of the knee joint, which provides self-braking due to a coupling with a split disc. Results. The study made it possible to substantiate the practical possibility of creating a knee joint of prosthetics for high amputation with a braking device made in the form of a split disc clutch. Discussion. Currently, there are various designs of knee joint that have mechanisms of buckling. When considering modern knee joint of well-known manufacturers, the main ways of ensuring buckling resistance are determined. The polycentric knee module of the company "Ossur" implements the principle of knee locking due to the displacement of the instantaneous axis when the knee is extended, thereby providing buckling resistance. In the Ottobock knee joint, the knee axis is automatically closed under the influence of human weight. Domestic manufacturers of knee modules are ORTHOS (Novosibirsk) and Metiz. Also, the scientific and production corporation "Precision Instrument Engineering Systems" (NPC SPP, part of Roscosmos) announced the production of the knee module "Aktiv-2". Due to the restriction of imports of foreign products, state prosthetic and orthopedic enterprises are interested in the development and production of domestic prosthetic and orthopedic products, including artificial knee joints of various designs. Conclusions. The principles of constructing the design of the knee joint of the above knee prosthesis have been formed

Paleointensity Results From Pliocene Lavas of the Lesser Caucasus Obtained Using the Multispecimen Parallel Differential pTRM Method: A Comparison With Thellier- Thellier and IZZI Data

We report paleointensity results obtained with the multispecimen method (MSP) over the Pliocene sequence of Apnia (Georgia) which records a polarity reversal. Paleointensity determinations with the multispecimen technique were performed on 12 flows with the original (MSP-DB) and the domain-state corrected (MSP-DSC) protocol. Eight MSP-DSC determinations passed the proposed quality criteria. To obtain highly reliable data through the agreement between intensity values from different methods, MSP results were combined with paleointensities from a previous study with Thellier-type methods and especially strict selection criteria (RCRIT) on same flows (Sánchez-Moreno et al., 2020). Application of this multimethod procedure resulted in three new paleointensities including both MSP and Thellier-type results and an additional one obtained with two different Thellier-type methods, yielding one paleointensity of 36.9 µT in the normal-polarity, and three paleointensities between 19.2 and 24.1 µT in the reverse-polarity section. Additionally, Thellier-type data have been reinterpreted in this study with more flexible criteria (TTP) and the results combined with the MSP data. As a result, four flows yield paleointensities including MSP and Thellier-type determinations and seven include paleointensities obtained with two different Thellier-type methods. Results range from 37.2 and 44.3 μT in the normal-polarity and from 12.5 to 24.6 μT in the reverse-polarity section. Comparison of results from the four flows yielding multimethod determinations applying RCRIT criteria with those from the same flows under TTP criteria yields no significant difference in paleointensity values and their experimental uncertainty. Thus, application of a multimethod approach supports the possibility of using TTP criteria.Project PID2019-105796/10.13039/501100011033 (Agencia Estatal de Investigación, Spain), project BU066U16 (Junta de Castilla y León, Spain) and pre-doctoral grant BES-2013-064060 (MINECO, Spain). MCR acknowledges funding from the Fulbright Commission and the Spanish Ministry of Science, Innovation and Universities for a research stay at Hawaii University at Manoa. AG is grateful to the financial support given by DGAPA-PAPIIT IN101717. At Montpellier laboratory, the FUReMAG rapid furnace construction was supported by the French National Agency for Research (ANR-12-BS06-0015)

Prospects in Analytical Atomic Spectrometry

Tendencies in five main branches of atomic spectrometry (absorption, emission, mass, fluorescence and ionization spectrometry) are considered. The first three techniques are the most widespread and universal, with the best sensitivity attributed to atomic mass spectrometry. In the direct elemental analysis of solid samples, the leading roles are now conquered by laser-induced breakdown and laser ablation mass spectrometry, and the related techniques with transfer of the laser ablation products into inductively-coupled plasma. Advances in design of diode lasers and optical parametric oscillators promote developments in fluorescence and ionization spectrometry and also in absorption techniques where uses of optical cavities for increased effective absorption pathlength are expected to expand. Prospects for analytical instrumentation are seen in higher productivity, portability, miniaturization, incorporation of advanced software, automated sample preparation and transition to the multifunctional modular architecture. Steady progress and growth in applications of plasma- and laser-based methods are observed. An interest towards the absolute (standardless) analysis has revived, particularly in the emission spectrometry.Comment: Proofread copy with an added full reference list of 279 citations. A pdf version of the final published review may be requested from Alexander Bol'shakov <[email protected]

Unexpected changes in the oxic/anoxic interface in the Black Sea

THE Black Sea is the largest anoxic marine basin in the world today1. Below the layer of oxygenated surface water, hydrogen sulphide builds up to concentrations as high as 425 μM in the deep water down to a maximum depth of 2,200 m (ref. 2). The hydrographic regime is characterized by low-salinity surface water of river origin overlying high-salinity deep water of Mediterranean origin1,3. A steep pycnocline, centred at about 50 m is the primary physical barrier to mixing and is the origin of the stability of the anoxic (oxygen/hydrogen sulphide) interface. Here we report new observations, however, that indicate dramatic changes in the oceanographic characteristics of the anoxic interface of the Black Sea over decadal or shorter timescales. The anoxic, sulphide-containing interface has moved up in the water column since the last US cruises in 1969 and 1975. In addition, a suboxic zone overlays the sulphide-containing deep water. The expected overlap of oxygen and sulphide was not present. We believe that these observations result from horizontal mixing or flushing events that inject denser, saltier water into the relevant part of the water column. It is possible that man-made reduction in freshwater inflow into the Black Sea could cause these changes, although natural variability cannot be discounted. © 1989 Nature Publishing Group