A laser-diode-pumped 1.54-μm passive Q-switched erbium doped glass laser was reported. We utilize a laser diode with wavelength of 973nm to pump a 1-mm Er/Yb co-doped phosphate glass with the erbium and ytterbium con...A laser-diode-pumped 1.54-μm passive Q-switched erbium doped glass laser was reported. We utilize a laser diode with wavelength of 973nm to pump a 1-mm Er/Yb co-doped phosphate glass with the erbium and ytterbium concentrations of 1 wt.% and 21 wt.%, respectively. A Co^2＋ ：MgAl2O4 slab crystal was used as a passive Q- switcher. Q-switched pulses with repetition frequency of 800Hz, width of 7.4ns, peak power of 2.2kW and average power of 13.3 m W were obtained when absorbed pump power was 4 75 m W. A sandwich structure of the Q- switched microchip Er/Yb glass laser was demonstrated, which shows shorter pulse width of 6.8 ns. Dependences of pulse duration and repetition frequency on pump power were also investigated.展开更多
Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz wave...Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz waves to the tissue water,as a medium for biochemical reactions and a main endogenous marker for THz spectroscopy and imaging.Tissues of the brain have an exceptionally high content of water.This factor,along with the features of the structural organization and biochemistry of neuronal and glial tissues,makes the brain an exciting subject to study in the THz range.In this paper,progress and prospects of THz technology in neurodiagnostics are overviewed,including diagnosis of neurodegenerative disease,myelin deficit,tumors of the central nervous system(with an emphasis on brain gliomas),and traumatic brain injuries.Fundamental and applied challenges in study of the THz-wave–brain tissue interactions and development of the THz biomedical tools and systems for neurodiagnostics are discussed.展开更多
The equation was presented for the spontaneous emission rate Anano of the two-level optical centers in the subwavelength eilipsoi- dal nanocrystals embedded in a dielectric medium. An important result was that the rat...The equation was presented for the spontaneous emission rate Anano of the two-level optical centers in the subwavelength eilipsoi- dal nanocrystals embedded in a dielectric medium. An important result was that the ratio Anano/Abulk could be estimated without recourse to a particular local-field model. On the ground of this equation the expression was derived for linestrength of electric-dipole transition in trivalent rare-earth ions. The applicability of the Judd-Ofelt equation for nanoparticles was discussed.展开更多
Polycrystalline diamond（PCD） films 100 mm in diameter are grown by 915 MHz microwave plasma chemical vapor deposition（MPCVD） at different process parameters,and their thermal conductivity（TC） is evaluated by a l...Polycrystalline diamond（PCD） films 100 mm in diameter are grown by 915 MHz microwave plasma chemical vapor deposition（MPCVD） at different process parameters,and their thermal conductivity（TC） is evaluated by a laser flash technique（LFT） in the temperature range of230-380 K.The phase purity and quality of the films are assessed by micro-Raman spectroscopy based on the diamond Raman peak width and the amorphous carbon（a-C） presence in the spectra.Decreasing and increasing dependencies for TC with temperature are found for high and low quality samples,respectively.TC,as high as 1950 ± 230 W m-1 K-1 at room temperature,is measured for the most perfect material.A linear correlation between the TC at room temperature and the fraction of the diamond component in the Raman spectrum for the films is established.展开更多
Dispersoid hardening is a key factor in increasing the recrystallization resistance and mechanical strength of non-heat treatable aluminum-based alloys.Mn and Zr are the main elements that form dispersoids in commerci...Dispersoid hardening is a key factor in increasing the recrystallization resistance and mechanical strength of non-heat treatable aluminum-based alloys.Mn and Zr are the main elements that form dispersoids in commercial Al-based alloys.In this work,the annealing-induced precipitation behavior,the grain structure,and the mechanical properties of Al-3.0 Mg-1.1 Mn and Al-3.0 Mg-1.1 Mn-0.25 Zr alloys were studied.The microstructure and the mechanical properties were significantly affected by annealing regimes after casting for both alloys.The research demonstrated a possibility to form high-density distributed quasicrystalline-structured I-phase precipitates with a mean size of 29 nm during low-temperature annealing of as-cast alloys.Fine manganese-bearing precipitates of I-phase increased recrystallization resistance and significantly enhanced the mechanical strength of the alloys studied.The estimated strengthening effect owing to I-phase precipitation was 150 MPa.Due to the formation of L1_(2)-structured Al3Zr dispersoids with a mean size of 5.7 nm,additional alloying with Zr increased yield strength by about 90 MPa.The L1_(2)-phase strengthening effect was estimated through the dislocation bypass looping and shearing mechanisms.展开更多
Electron spin resonance （ESR） in polycrystalline diamond films grown by dc arc-jet and microwave plasma chemical vapour deposition is studied. The films with nitrogen impurity concentration up to 8 × 10^18 cm^-...Electron spin resonance （ESR） in polycrystalline diamond films grown by dc arc-jet and microwave plasma chemical vapour deposition is studied. The films with nitrogen impurity concentration up to 8 × 10^18 cm^-3 are also characterized by Raman, cathodoluminescence and optical absorption spectra. The ESR signal from P1 centre with g-factor of 2.0024 （nitrogen impurity atom occupying C site in diamond lattice） is found to exhibit an inversion with increasing the microwave power in an H102 resonator. The spin inversion effect could be of interest for further consideration of N-doped diamonds as a medium for masers operated at room temperature.展开更多
We examine the effect of laser focusing on the effectiveness of a recently discussed scheme[M.F.Ciappina et al.,Phys.Rev.A 99,043405(2019)and M.F.Ciappina and S.V.Popruzhenko,Laser Phys.Lett.17,025301(2020)]for in sit...We examine the effect of laser focusing on the effectiveness of a recently discussed scheme[M.F.Ciappina et al.,Phys.Rev.A 99,043405(2019)and M.F.Ciappina and S.V.Popruzhenko,Laser Phys.Lett.17,025301(2020)]for in situ determination of ultrahigh intensities of electromagnetic radiation delivered by multi-petawatt laser facilities.Using two model intensity distributions in the focus of a laser beam,we show how the resulting yields of highly charged ions generated in the process of multiple sequential tunneling of electrons from atoms depend on the shapes of these distributions.Our findings lead to the conclusion that an accurate extraction of the peak laser intensity can be made either in the near-threshold regime,when the production of the highest charge state happens only in a small part of the laser focus close to the point where the intensity is maximal or through the determination of the points where the ion yields of close charges become equal.We show that for realistic parameters of the gas target,the number of ions generated in the central part of the focus in the threshold regime should be sufficient for a reliable measurement with highly sensitive time-of-flight detectors.Although the positions of the intersection points generally depend on the focal shape,they can be used to localize the peak intensity value in certain intervals.Finally,the slope of the intensity-dependent ion yields is shown to be robust with respect to both the focal spot size and the spatial distribution of the laser intensity in the focus.When these slopes can be measured,they will provide the most accurate determination of the peak intensity value within the considered tunnel ionization scheme.In addition to this analysis,we discuss the method in comparison with other recently proposed approaches for direct measurement of extreme laser intensities.展开更多
Rotary swaging(RS)of alloy Mg-1.03Zn-0.66Ca(ZX11)was shown to refine the average grain size to 4.5±1.2μm in a longitudinal section and 4.8±0.9μm in a transverse section.In addition,a small amount of Mg2Ca ...Rotary swaging(RS)of alloy Mg-1.03Zn-0.66Ca(ZX11)was shown to refine the average grain size to 4.5±1.2μm in a longitudinal section and 4.8±0.9μm in a transverse section.In addition,a small amount of Mg2Ca particles about 300nm in size and Mg6Zn3Ca2 particles with a size of about lOOnm was detected.This resulted in pronounced strengthening:the yield strength and the ultimate tensile strength rose to 210±8 MPa and 276±6 MPa,respectively,while the elongation hardly decreased(22.0±1.8% and 18.3±2.9% before and after RS).Furthermore,RS led to an increase in the fatigue limit of the alloy from 120 MPa to 135 MPa and did not impair its resistance to chemical corrosion.The studies in vitro showed that ZX11 induces hemolysis without inhibiting the viability of peripheral blood mononuclear cells and has a more pronounced cytotoxic effect on tumor cells in comparison with non-transformed cells.No significant difference of the latter effect between the initial and the deformed states was observed.展开更多
Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out.The content range for the formation of the two-phase structure MgSS(Mg solid solution)+LPSO(long-period stacking ordered)in alloys of the Mg-Zn-Y-Z...Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out.The content range for the formation of the two-phase structure MgSS(Mg solid solution)+LPSO(long-period stacking ordered)in alloys of the Mg-Zn-Y-Zr system was determined by thermodynamic calculations.The effect of heat treatment regimes on microstructure,mechanical,and corrosion properties was invest-igated.The fluidity,hot tearing tendency,and ignition temperature of the alloys were determined.The best combination of castability,mechanical,and corrosion properties was found for the Mg-2.4Zn-4Y-0.8Zr alloy.The alloys studied are superior to their industrial counterparts in terms of technological properties,while maintain high corrosion and mechanical properties.The increased level of pro-perties is achieved by a suitable heat treatment regime that provides a complete transformation of the 18R to 14H modification of the LPSO phase.展开更多
The local coordination structures around the doping Yb2＋ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vac...The local coordination structures around the doping Yb2＋ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vacancy in the local environment of the doping Yb2＋ were calculated to study the effect of the doping on the local coordination structures of Yb2＋. Using the calculated local structures, we obtained the crystal-field parameters for the Yb2＋ ions doped in sodium and potassium halides by a method based on the combination of the quantum-chemical calculations and the effective Hamiltonian method. The calculated crystal-field parameters were analyzed and compared with the fitted results.展开更多
The mono-module disk laser concept is an effective design for diode-pumped solid-state lasers, which allows the realization of lasers with super-high output power, having very good efficiency and also excellent beam q...The mono-module disk laser concept is an effective design for diode-pumped solid-state lasers, which allows the realization of lasers with super-high output power, having very good efficiency and also excellent beam quality. Since the first demonstration of the principle in 1964 the output power of mono-module disk has been increased to the level of few kW in continuous wave (CW) mode of operation. “Zig-Zag” disk laser geometry does not look like as a perspective one for further output parameters growing. The scaling laws for mono-module disk laser design show that the limits for CW mode of operation are far beyond 100 kW for output power and the energy can be higher than 100 J in pulsed mode of operation. Due to the efficient porous cooling technology and possibility of amplified spontaneous emission (ASE) suppression the operation of the mono-module disk laser geometry is possible in CW and pulse-periodical (P-P) modes at extremely high output power.展开更多
Multiwave laser medical device"Livadia"has been developed for bactericidal and therapeutic impact on the affected organism parts.This device is on the diode pumped solid-state laser and main wavelength radia...Multiwave laser medical device"Livadia"has been developed for bactericidal and therapeutic impact on the affected organism parts.This device is on the diode pumped solid-state laser and main wavelength radiation conversion 1064 nm into the second harmonic 532 nm and fourth harmonic 266 nm.It has been shown that UV radiation on the wavelength 266 nm on bronchia mucosa with various inflammation types improves regenerative processes in bronchia tissues which decreases treatment deadline.展开更多
The advent of the laser has placed stringent requirements on the fabrication, performance and quality of optical elements employed within systems for most practical applications. Their high power performance is genera...The advent of the laser has placed stringent requirements on the fabrication, performance and quality of optical elements employed within systems for most practical applications. Their high power performance is generally governed by three distinct steps, firstly the absorption of incident optical radiation (governed primarily by various absorption mechanisms);secondly, followed by a temperature increase and response governed primarily by thermal properties and finally the elements thermo-optical and thermomechanical response, e.g., distortion, stress birefringenous fracture, etc. All of which needs to be understood in the design as efficient, compact, reliable and useful for many applications high power systems, under a variety of operating conditions, pulsed and continuous wave, rep-rated or burst mode of varying duty cycles.展开更多
New approach to the problem of laser jet engine (LJE) creation is based on the use of shock waves (SW) resonance association mechanism, generated by the optical pulsating discharge (OPD). For the creation OPD is propo...New approach to the problem of laser jet engine (LJE) creation is based on the use of shock waves (SW) resonance association mechanism, generated by the optical pulsating discharge (OPD). For the creation OPD is proposed to use powerful pulse - periodic (P-P) laser radiation with duration of pulses ~ 100 - 150 ns and high pulse repetition frequency ~ 50 - 100 kHz. OPD is formed with the help of matrix of reflectors (MR). This is allowed: several times to increase the effectiveness of laser emission use for purposes of LJE creation, to avoid strong impact loads on the apparatus, to exclude the thermal action of laser plasma on the reflector, to decrease the laser emission screening by plasma, to remove the problem of the resonance oscillations appearance into the object moved with the help of laser. In our article the estimations of possible LJE thrust levels under the conditions of the proposed mechanism of reactive motion are given. Also, the new approaches to the creation of the high power high repetition rate laser systems for the “Impulsar” program are examined.展开更多
At present time the development of new methods of the single-wire long distance energy transfer is of great interest of science. These works are the prolongation and development of Tesla studies in the beginning of XX...At present time the development of new methods of the single-wire long distance energy transfer is of great interest of science. These works are the prolongation and development of Tesla studies in the beginning of XX century. In particular, not so long ago highly effective energy transfer between two resonant circuits, connected by very thin wire (100 mkm) with more than kilometer length had been demonstrated. In these experiments Tesla type transformers with the output voltage about several ten kilovolts and output power up to 10 kW were used [1]. An effective replacement of wire by laser-plasma channel in that configuration of experiment would be the obvious improvement of demonstrated technology.展开更多
There are many appearances in the literature of reliable observations of studying so-called “jets” and “sprites” - the discharges in the gigantic natural capacitor “Ionosphere-Earth” [1]. The volume of such a di...There are many appearances in the literature of reliable observations of studying so-called “jets” and “sprites” - the discharges in the gigantic natural capacitor “Ionosphere-Earth” [1]. The volume of such a discharge is approximately 5-10 thousand cubic kilometers and usually it appears above the surface of ocean. There are the cases also of above mentioned discharges on the ground. The value of the energy transferred to the earth can comprise to several terajoule. Events are accompanied by the emission of the waves of ultra-low frequency. Their study has the significant interest from many points of view. The essence of the observed irregular phenomena consists of the electromechanical conversion of the energy excesses of natural electricity into mechanical and thermal energy of cyclones, typhoons and other natural cataclysms. The ionosphere can retain only the specific quantity of energy. Otherwise, it discards the surpluses of electricity through the atmosphere or transforms them into the energy of storms, in that number and inside the Earth. By using the part of the natural electricity for useful purposes it is possible to govern the weather of planet. Causing the artificial breakdowns of the ionosphere it could be possible to arrange the discharge of the controlled aqueous sediments at the necessary points of the globe. It could be possible as well to attempt to regulate the climate of planet and to decrease the amplitudes of the magnetic storms, earthquakes and hurricanes.展开更多
The adequate method of antibiotic choice is reported using the laserfluorescence analysis of blood plasma with the laboratory diagnostic device"Spectrolux-MB".The method is based on the ability of micro-orga...The adequate method of antibiotic choice is reported using the laserfluorescence analysis of blood plasma with the laboratory diagnostic device"Spectrolux-MB".The method is based on the ability of micro-organisms and products of their vital functions(metabolism)tofluoresce under laser radiation.The method offluorescence analysis has great prospects in urgent surgery and other medicine brunches due to its high information content,low cost(compared to other methods of express-diagnostics)and high speed of information acquisition.展开更多
基金Supported by the Program for the New Century Excellent Talents, Excellent Young Teachers in Universities and Scientific Research Foundation for Returned 0verseas Chinese Scholars by M0E and the Natural Science Foundation of Tianjin City 05YFGPGX05100.
文摘A laser-diode-pumped 1.54-μm passive Q-switched erbium doped glass laser was reported. We utilize a laser diode with wavelength of 973nm to pump a 1-mm Er/Yb co-doped phosphate glass with the erbium and ytterbium concentrations of 1 wt.% and 21 wt.%, respectively. A Co^2＋ ：MgAl2O4 slab crystal was used as a passive Q- switcher. Q-switched pulses with repetition frequency of 800Hz, width of 7.4ns, peak power of 2.2kW and average power of 13.3 m W were obtained when absorbed pump power was 4 75 m W. A sandwich structure of the Q- switched microchip Er/Yb glass laser was demonstrated, which shows shorter pulse width of 6.8 ns. Dependences of pulse duration and repetition frequency on pump power were also investigated.
基金The work was supported by the Russian Science Foundation,Project#22-22-00596.
文摘Terahertz(THz)technology offers novel opportunities in biology and medicine,thanks to the unique features of THzwave interactions with tissues and cells.Among them,we particularly notice strong sensitivity of THz waves to the tissue water,as a medium for biochemical reactions and a main endogenous marker for THz spectroscopy and imaging.Tissues of the brain have an exceptionally high content of water.This factor,along with the features of the structural organization and biochemistry of neuronal and glial tissues,makes the brain an exciting subject to study in the THz range.In this paper,progress and prospects of THz technology in neurodiagnostics are overviewed,including diagnosis of neurodegenerative disease,myelin deficit,tumors of the central nervous system(with an emphasis on brain gliomas),and traumatic brain injuries.Fundamental and applied challenges in study of the THz-wave–brain tissue interactions and development of the THz biomedical tools and systems for neurodiagnostics are discussed.
基金supported in part by the Russian Foundation for Basic Research (08-02-01058-a)the US Civilian Research and Development Foundation for the New Independent States of the Former Soviet Union (CRDF) (RUP2-1517-MO-06)
文摘The equation was presented for the spontaneous emission rate Anano of the two-level optical centers in the subwavelength eilipsoi- dal nanocrystals embedded in a dielectric medium. An important result was that the ratio Anano/Abulk could be estimated without recourse to a particular local-field model. On the ground of this equation the expression was derived for linestrength of electric-dipole transition in trivalent rare-earth ions. The applicability of the Judd-Ofelt equation for nanoparticles was discussed.
基金supported by the Russian Ministry of Education and Science(RMES),Agreement No.14.613.21.0021,unique ID No.RFMEFI61314X0021the Department ofScience & Technology(DST),India,grant No.GAP0246 under the joint RMES-DST Research Collaboration Agreement 'Development of large size polycrystalline CVD diamond material for optical windows and support rods in high power microwave tubes'
文摘Polycrystalline diamond（PCD） films 100 mm in diameter are grown by 915 MHz microwave plasma chemical vapor deposition（MPCVD） at different process parameters,and their thermal conductivity（TC） is evaluated by a laser flash technique（LFT） in the temperature range of230-380 K.The phase purity and quality of the films are assessed by micro-Raman spectroscopy based on the diamond Raman peak width and the amorphous carbon（a-C） presence in the spectra.Decreasing and increasing dependencies for TC with temperature are found for high and low quality samples,respectively.TC,as high as 1950 ± 230 W m-1 K-1 at room temperature,is measured for the most perfect material.A linear correlation between the TC at room temperature and the fraction of the diamond component in the Raman spectrum for the films is established.
基金funded by RFBF grant#20-03-00778the financial support of the Ministry of Education and Science of the Russian Federation in the framework of Increase Competitiveness Program of NUST MISIS for the part of the grain structure analysis。
文摘Dispersoid hardening is a key factor in increasing the recrystallization resistance and mechanical strength of non-heat treatable aluminum-based alloys.Mn and Zr are the main elements that form dispersoids in commercial Al-based alloys.In this work,the annealing-induced precipitation behavior,the grain structure,and the mechanical properties of Al-3.0 Mg-1.1 Mn and Al-3.0 Mg-1.1 Mn-0.25 Zr alloys were studied.The microstructure and the mechanical properties were significantly affected by annealing regimes after casting for both alloys.The research demonstrated a possibility to form high-density distributed quasicrystalline-structured I-phase precipitates with a mean size of 29 nm during low-temperature annealing of as-cast alloys.Fine manganese-bearing precipitates of I-phase increased recrystallization resistance and significantly enhanced the mechanical strength of the alloys studied.The estimated strengthening effect owing to I-phase precipitation was 150 MPa.Due to the formation of L1_(2)-structured Al3Zr dispersoids with a mean size of 5.7 nm,additional alloying with Zr increased yield strength by about 90 MPa.The L1_(2)-phase strengthening effect was estimated through the dislocation bypass looping and shearing mechanisms.
基金Supported by the National Natural Science Foundation of China under Grant Nos 50372007 and 50572007, Russian Fund for Basic Research under Grant Nos 06-02-39031 and 07-03-00956, and Belarus Republic Foundation for Basic Research under Grant No F05-281.
文摘Electron spin resonance （ESR） in polycrystalline diamond films grown by dc arc-jet and microwave plasma chemical vapour deposition is studied. The films with nitrogen impurity concentration up to 8 × 10^18 cm^-3 are also characterized by Raman, cathodoluminescence and optical absorption spectra. The ESR signal from P1 centre with g-factor of 2.0024 （nitrogen impurity atom occupying C site in diamond lattice） is found to exhibit an inversion with increasing the microwave power in an H102 resonator. The spin inversion effect could be of interest for further consideration of N-doped diamonds as a medium for masers operated at room temperature.
基金support from the Russian Foundation for Basic Research via Grant No.19-02-00643.M.F.C.acknowledges the Spanish Ministry MINECO and State Research Agency AEI(FIDEUA PID2019-106901GB-I00/10.13039/501100011033,SEVERO OCHOA No.SEV-2015-0522,FPI)European Social Fund,Fundacio Cellex,Fundacio Mir-Puig,Generalitat de Catalunya(AGAUR Grant No.2017 SGR 1341,CERCA program,QuantumCATU16-011424,co-funded by ERDFOperational Program of Catalonia 2014-2020)+2 种基金MINECO-EU QUANTERA MAQS(funded by The State Research Agency(AEI)PCI2019-111828-2/10.13039/501100011033)the National Science Centre,Poland-Symfonia Grant No.2016/20/W/ST4/00314the project Advanced Research Using High Intensity Laser Produced Photons and Particles(Grant No.CZ.02.1.01/0.0/0.0/16_019/0000789)through the European Regional Development Fund(ADONIS).
文摘We examine the effect of laser focusing on the effectiveness of a recently discussed scheme[M.F.Ciappina et al.,Phys.Rev.A 99,043405(2019)and M.F.Ciappina and S.V.Popruzhenko,Laser Phys.Lett.17,025301(2020)]for in situ determination of ultrahigh intensities of electromagnetic radiation delivered by multi-petawatt laser facilities.Using two model intensity distributions in the focus of a laser beam,we show how the resulting yields of highly charged ions generated in the process of multiple sequential tunneling of electrons from atoms depend on the shapes of these distributions.Our findings lead to the conclusion that an accurate extraction of the peak laser intensity can be made either in the near-threshold regime,when the production of the highest charge state happens only in a small part of the laser focus close to the point where the intensity is maximal or through the determination of the points where the ion yields of close charges become equal.We show that for realistic parameters of the gas target,the number of ions generated in the central part of the focus in the threshold regime should be sufficient for a reliable measurement with highly sensitive time-of-flight detectors.Although the positions of the intersection points generally depend on the focal shape,they can be used to localize the peak intensity value in certain intervals.Finally,the slope of the intensity-dependent ion yields is shown to be robust with respect to both the focal spot size and the spatial distribution of the laser intensity in the focus.When these slopes can be measured,they will provide the most accurate determination of the peak intensity value within the considered tunnel ionization scheme.In addition to this analysis,we discuss the method in comparison with other recently proposed approaches for direct measurement of extreme laser intensities.
基金Funding support of investigations of microstructure,mechanical properties,corrosion resistance,biocompatibility and cytotoxicity was provided by the Russian Science Foundation(project#18-45-06010)Part of this work relating to studies of fatigue behavior was carried out within the governmental task#075-00947-20-00.
文摘Rotary swaging(RS)of alloy Mg-1.03Zn-0.66Ca(ZX11)was shown to refine the average grain size to 4.5±1.2μm in a longitudinal section and 4.8±0.9μm in a transverse section.In addition,a small amount of Mg2Ca particles about 300nm in size and Mg6Zn3Ca2 particles with a size of about lOOnm was detected.This resulted in pronounced strengthening:the yield strength and the ultimate tensile strength rose to 210±8 MPa and 276±6 MPa,respectively,while the elongation hardly decreased(22.0±1.8% and 18.3±2.9% before and after RS).Furthermore,RS led to an increase in the fatigue limit of the alloy from 120 MPa to 135 MPa and did not impair its resistance to chemical corrosion.The studies in vitro showed that ZX11 induces hemolysis without inhibiting the viability of peripheral blood mononuclear cells and has a more pronounced cytotoxic effect on tumor cells in comparison with non-transformed cells.No significant difference of the latter effect between the initial and the deformed states was observed.
基金the Ministry of Science and Higher Education of the Russian Federation for financial support under the Megagrant(No.075-15-2022-1133)by the Strategic Academic Leadership Program“Priority 2030”(No.K2-2022-001)For the sample preparation and TEM investigation,the authors thank the Collective Use Equipment Center“Material Science and Metallurgy”for the equipment modernization program represented by the Ministry of Higher Education and Science of Russian Federation(No.075-15-2021-696).
文摘Complex studies of new Mg-Zn-Y-Zr system alloys have been carried out.The content range for the formation of the two-phase structure MgSS(Mg solid solution)+LPSO(long-period stacking ordered)in alloys of the Mg-Zn-Y-Zr system was determined by thermodynamic calculations.The effect of heat treatment regimes on microstructure,mechanical,and corrosion properties was invest-igated.The fluidity,hot tearing tendency,and ignition temperature of the alloys were determined.The best combination of castability,mechanical,and corrosion properties was found for the Mg-2.4Zn-4Y-0.8Zr alloy.The alloys studied are superior to their industrial counterparts in terms of technological properties,while maintain high corrosion and mechanical properties.The increased level of pro-perties is achieved by a suitable heat treatment regime that provides a complete transformation of the 18R to 14H modification of the LPSO phase.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11074315, 11074245, 90922022, and 11111120060)the Russian Foundation for Basic Research (Grant No. 11-02-91152)the European Social Fund (Grant No. MTT50)
文摘The local coordination structures around the doping Yb2＋ ions in sodium and potassium halides were calculated by using the first-principles supercell model. Both the cases with and without the charge compensation vacancy in the local environment of the doping Yb2＋ were calculated to study the effect of the doping on the local coordination structures of Yb2＋. Using the calculated local structures, we obtained the crystal-field parameters for the Yb2＋ ions doped in sodium and potassium halides by a method based on the combination of the quantum-chemical calculations and the effective Hamiltonian method. The calculated crystal-field parameters were analyzed and compared with the fitted results.
文摘The mono-module disk laser concept is an effective design for diode-pumped solid-state lasers, which allows the realization of lasers with super-high output power, having very good efficiency and also excellent beam quality. Since the first demonstration of the principle in 1964 the output power of mono-module disk has been increased to the level of few kW in continuous wave (CW) mode of operation. “Zig-Zag” disk laser geometry does not look like as a perspective one for further output parameters growing. The scaling laws for mono-module disk laser design show that the limits for CW mode of operation are far beyond 100 kW for output power and the energy can be higher than 100 J in pulsed mode of operation. Due to the efficient porous cooling technology and possibility of amplified spontaneous emission (ASE) suppression the operation of the mono-module disk laser geometry is possible in CW and pulse-periodical (P-P) modes at extremely high output power.
基金This work was supported by Advanced Energy Technologies Ltd.
文摘Multiwave laser medical device"Livadia"has been developed for bactericidal and therapeutic impact on the affected organism parts.This device is on the diode pumped solid-state laser and main wavelength radiation conversion 1064 nm into the second harmonic 532 nm and fourth harmonic 266 nm.It has been shown that UV radiation on the wavelength 266 nm on bronchia mucosa with various inflammation types improves regenerative processes in bronchia tissues which decreases treatment deadline.
文摘The advent of the laser has placed stringent requirements on the fabrication, performance and quality of optical elements employed within systems for most practical applications. Their high power performance is generally governed by three distinct steps, firstly the absorption of incident optical radiation (governed primarily by various absorption mechanisms);secondly, followed by a temperature increase and response governed primarily by thermal properties and finally the elements thermo-optical and thermomechanical response, e.g., distortion, stress birefringenous fracture, etc. All of which needs to be understood in the design as efficient, compact, reliable and useful for many applications high power systems, under a variety of operating conditions, pulsed and continuous wave, rep-rated or burst mode of varying duty cycles.
文摘New approach to the problem of laser jet engine (LJE) creation is based on the use of shock waves (SW) resonance association mechanism, generated by the optical pulsating discharge (OPD). For the creation OPD is proposed to use powerful pulse - periodic (P-P) laser radiation with duration of pulses ~ 100 - 150 ns and high pulse repetition frequency ~ 50 - 100 kHz. OPD is formed with the help of matrix of reflectors (MR). This is allowed: several times to increase the effectiveness of laser emission use for purposes of LJE creation, to avoid strong impact loads on the apparatus, to exclude the thermal action of laser plasma on the reflector, to decrease the laser emission screening by plasma, to remove the problem of the resonance oscillations appearance into the object moved with the help of laser. In our article the estimations of possible LJE thrust levels under the conditions of the proposed mechanism of reactive motion are given. Also, the new approaches to the creation of the high power high repetition rate laser systems for the “Impulsar” program are examined.
文摘At present time the development of new methods of the single-wire long distance energy transfer is of great interest of science. These works are the prolongation and development of Tesla studies in the beginning of XX century. In particular, not so long ago highly effective energy transfer between two resonant circuits, connected by very thin wire (100 mkm) with more than kilometer length had been demonstrated. In these experiments Tesla type transformers with the output voltage about several ten kilovolts and output power up to 10 kW were used [1]. An effective replacement of wire by laser-plasma channel in that configuration of experiment would be the obvious improvement of demonstrated technology.
文摘There are many appearances in the literature of reliable observations of studying so-called “jets” and “sprites” - the discharges in the gigantic natural capacitor “Ionosphere-Earth” [1]. The volume of such a discharge is approximately 5-10 thousand cubic kilometers and usually it appears above the surface of ocean. There are the cases also of above mentioned discharges on the ground. The value of the energy transferred to the earth can comprise to several terajoule. Events are accompanied by the emission of the waves of ultra-low frequency. Their study has the significant interest from many points of view. The essence of the observed irregular phenomena consists of the electromechanical conversion of the energy excesses of natural electricity into mechanical and thermal energy of cyclones, typhoons and other natural cataclysms. The ionosphere can retain only the specific quantity of energy. Otherwise, it discards the surpluses of electricity through the atmosphere or transforms them into the energy of storms, in that number and inside the Earth. By using the part of the natural electricity for useful purposes it is possible to govern the weather of planet. Causing the artificial breakdowns of the ionosphere it could be possible to arrange the discharge of the controlled aqueous sediments at the necessary points of the globe. It could be possible as well to attempt to regulate the climate of planet and to decrease the amplitudes of the magnetic storms, earthquakes and hurricanes.
文摘The adequate method of antibiotic choice is reported using the laserfluorescence analysis of blood plasma with the laboratory diagnostic device"Spectrolux-MB".The method is based on the ability of micro-organisms and products of their vital functions(metabolism)tofluoresce under laser radiation.The method offluorescence analysis has great prospects in urgent surgery and other medicine brunches due to its high information content,low cost(compared to other methods of express-diagnostics)and high speed of information acquisition.
