A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100...A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.展开更多
We report the observation of bubble generation and migration in a germanate g/ass during irradiation by a femtosecond laser of high repetition rate. Bubbles are formed around the focal area of the laser beam, and thei...We report the observation of bubble generation and migration in a germanate g/ass during irradiation by a femtosecond laser of high repetition rate. Bubbles are formed around the focal area of the laser beam, and their movement indicates the presence of thermal gravity convection in the glass melt, which is beyond the existing theoretical model about temperature l^eld of focal area. Inside the bubbles, oxygen molecules are observed by the con focal Raman micro-spectroscopy. The generation of molecular oxygen and bubbles is explained in terms of the spatial separation of Ge and 0 ions and micro-explosion inside the glass melt.展开更多
Two kinds of germanate glasses singly doped with the ion concentration of 2.0mol.%Tm3＋ and 2.0mol.%Ho3＋, respectively, were prepared.According to McCumber theory, the absorption and stimulated emission cross-section...Two kinds of germanate glasses singly doped with the ion concentration of 2.0mol.%Tm3＋ and 2.0mol.%Ho3＋, respectively, were prepared.According to McCumber theory, the absorption and stimulated emission cross-sections corresponding to the 3H6←→3F4 transitions of Tm3＋（at 1.8 μm） and the 5I8←→5I7 transitions of Ho3＋（at 2.0 μm） were obtained, and respective gain cross-section spectra were also computed as a function of population inversion according to absorption and emission cross-sections and the ion concentrations.For Tm3＋-doped germanate glasses, the maximum of the absorption, emission, and gain cross-sections reached a value higher than those reported for fluorozirconate, fluoride, and oxyfluoride glasses.For Ho3＋-doped germanate glasses, the maximum of absorption, emission, and gain cross-sections reached a value higher than that reported for fluorozircoaluminate glasses.Hence, these Tm3＋-doped and Ho3＋-doped germanate glasses exhibited an advantage for application in mid-infrared lasers at about 1.8 and 2.0 μm wavelength.展开更多
A layered zirconogermanate, （H2DETA）[ZrGe3O8F2]（1）, was hydro（solvo）thermally synthesized with diethylenetriamine（DETA） as template, and structurally determined by X-ray single-crystal diffraction. Compound 1 ...A layered zirconogermanate, （H2DETA）[ZrGe3O8F2]（1）, was hydro（solvo）thermally synthesized with diethylenetriamine（DETA） as template, and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallized in the monoclinic space group P21/c with data of unit cell： a=0.7644（2） nm, b=1.1235（2） nm, c=1.6860（3） nm, V=1.4479（5） nm^3,/a（Mo Ka）=6.931 mm^-1, Z=4, R1=0.0402 for 3236 reflections with Fo〉2σ（Fo）. The structure of compound I was formed by alternatively packing the inorganic layer of ZrGe3O8F2 and H2DETA templated molecules along （001） direction. It was worth pointing out that the odd bifurcated 7MR nets were surrounded by odd 3MR. The protonated and disordered H2DETA cations not only balanced the superfluous charges of framework but also stabilized the structure of compound 1 by the hydrogen bond between -NH3 group and oxygen on the framework. Furthermore, IR and TG were utilized to characterize the structure and thermal stability, respectively.展开更多
Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion ...Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion in doped samples,formations of Ge-related non-bridging oxygen hole center and Ge-related electron center defects after g-ray irradiation are inhibited.Thereby,Nb_(2)O_(5)dopant can enhance radiation resistance of BGG glass,and 1.0%Nb2O5 concentration is the best.展开更多
A novel gallium germanate (83/2 Na2O . 1/2 Ga2O3 . 24 GeO2) was synthsized by a sol-gel method and hydrothermal crystallization. The germanate was characterized with scanning electron microscopy, electronic energy spe...A novel gallium germanate (83/2 Na2O . 1/2 Ga2O3 . 24 GeO2) was synthsized by a sol-gel method and hydrothermal crystallization. The germanate was characterized with scanning electron microscopy, electronic energy spectrum, inductively couple plasma-emission spectrum and powder X-ray diffraction. The properties of crystal appearance, size, thermal stability and melting point were studied as well as some influence factors on synthesis process.展开更多
A novel indium germanate (183/2Na 2O·1/2In 2O 3·28GeO 2) was synthesized by a sol gel and hydrothermal crystallization. The germanate was characterized with scanning electronic microscopy, electronic en...A novel indium germanate (183/2Na 2O·1/2In 2O 3·28GeO 2) was synthesized by a sol gel and hydrothermal crystallization. The germanate was characterized with scanning electronic microscopy, electronic energy spectrum, inductively couple plasma emission spectrum and powder X ray diffraction. The properties on its crystal appearance, size, thermal stability and melting point, and some influent factors on synthesis were studied.展开更多
Bismuth(Bi)-doped near-infared(NIR)glass that can cover the entire optical communication window(850,1310,and1550 nm)has become the subject of extensive research for developing photonic devices,particularly,tunable fib...Bismuth(Bi)-doped near-infared(NIR)glass that can cover the entire optical communication window(850,1310,and1550 nm)has become the subject of extensive research for developing photonic devices,particularly,tunable fiber lasers and ultrabroadband optical amplifiers.However,the realization of highly efficient NIR luminescence from Bi-doped glass is still full of challenges.Notably,due to the co-existence of multiple Bi NIR centers in the glass,the origin of newly generated Bi NIR emission peaks at~930 and~1520 nm is still controversial.Here,we report a new Bi-doped nitridated germanate glass with tunable ultrabroadband NIR emission(850–1700 nm)and high external quantum efficiency(EQE)of~50%.A series of studies,including spectral analysis,nuclear magnetic resonance(NMR),and others,provide powerful evidence for the mechanism of luminescence enhancement and tunability,and make reasonable inferences about the origin of the new emission bands at~930 and~1520 nm.We believe that the results discussed above would enrich our understanding about multiple Bi NIR emission behaviors and contribute to the design and fabrication of highly efficient Bi-doped ultrabroadband wavelength-tunable optical glass fiber amplifiers and lasers in the future.展开更多
Emission enhancement at 2.7 μm is observed in Er^3＋/Pr^3＋--codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-μm emission and upeonversion intensity indicate efficient ene...Emission enhancement at 2.7 μm is observed in Er^3＋/Pr^3＋--codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-μm emission and upeonversion intensity indicate efficient energy transfer between Er^3＋ and Pr^3＋; the energy transfer efficiency is as high as 77.4%. The mechanisms of energy transfer are discussed in detail. The calculated emission cross-section of Er^3＋/Pr^3＋- codoped germanate glass is 8.44× 10 ^-21 cm^2, which suggests that Er^3＋/Pr^3＋-codoped germanate glass can be used to achieve efficient 2.7-μm emission.展开更多
Bismuth （Bi）-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reac...Bismuth （Bi）-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reach. Current Bi-dopcd silica glass fibers have to be made by modified chemical vapor deposition at a temperature higher than 2000℃. This unavoidably leads to the tremendous loss of Bi by evaporation, since the temperature is several hundred degrees Celsius higher than the Bi boiling temperature, and, therefore, trace Bi （-50 ppm） resides within the final product of silica fiber. So, the gain of such fiber is usually extremely low. One of the solutions is to make the fibers at a temperature much lower than the boiling temperature of Bi. The challenge for this is to find a lower melting point glass, which can stabilize Bi in the near infrared emission center and, meanwhile, does not lose glass transparency during fiber fabrication. None of previously reported Bi-doped multicomponent glasses can meet the prerequisite. Here, we, after hundreds of trials on optimization over glass components, activator content, melting temperature, etc., find a novel Bi-doped gallogermanate glass, which shows good tolerance to thermal impact and can accommodate a higher content of Bi. Consequently, we successfully manu- facture the germanate fiber by a rod-in-tube technique at 850℃. The fiber exhibits similar luminescence to the bulk glass, and it shows saturated absorption at 808 nm rather than 980 nm as the incident power becomes higher than 4 W. Amplified spontaneous emissions are observed upon the pumps of either 980 or 1064 nm from ger- manate fiber.展开更多
Ambroxol hydrochloride(2-amino-3,5-dibromo-N-methylbenzylamine hydrochloride)has been used as a mucolytic agent in the treatment of respiratory diseases since the late 1970s.Its effects on mucus membranes such as mucu...Ambroxol hydrochloride(2-amino-3,5-dibromo-N-methylbenzylamine hydrochloride)has been used as a mucolytic agent in the treatment of respiratory diseases since the late 1970s.Its effects on mucus membranes such as mucus disruption,increased mucus production,and low toxicity profile were addressed in its original German patent in 1966.These first described properties have kept Ambroxol available worldwide and over the counter in the pharmaceutical market to this day.展开更多
“Europe has missed this development opportunity because we are short of a long-term vision.”MORE than 40 exhibitors from 15 major vehicle brands around the world,representing the latest cutting-edge technologies and...“Europe has missed this development opportunity because we are short of a long-term vision.”MORE than 40 exhibitors from 15 major vehicle brands around the world,representing the latest cutting-edge technologies and models,gathered at the seventh China International Import Expo(CIIE),which was held in Shanghai from November 5 to 10.展开更多
In this exclusive interview,Michael Schumann,chairman of the Board of the German Federal Association for Economic Development and Foreign Trade,discusses Sino-German trade relations and the“out-of-proportion”debate ...In this exclusive interview,Michael Schumann,chairman of the Board of the German Federal Association for Economic Development and Foreign Trade,discusses Sino-German trade relations and the“out-of-proportion”debate on Xinjiang.展开更多
The research paper explores belongingness and identity in post-WWII German literature through the lens of iconic scholars,including Wolf,Şenocak,and Grass.The three authors are central and prominent figures in buildin...The research paper explores belongingness and identity in post-WWII German literature through the lens of iconic scholars,including Wolf,Şenocak,and Grass.The three authors are central and prominent figures in building German literature in the aftermath of the war.National divisions in Germany,rebuilding destroyed communities,and guilt struggles marked this literature.German authors utilized literature during the war to question and comprehend fractures,structures,and the comprehensive identity of a nation with issues of guilt,war,splitting,differences,and divisions.By comprehensively linking Wolf and Grass’authorships to modern debates on multiculturism and migration,we derive fundamental insights and ideas into their applicability to issues affecting our world today.Some of the contemporary issues are immigration,civil wars,and trauma affecting people.Authors like Grass had a significant role to play during post-WWII in Germany,like dealing with and handling migrant and refugee experiences,returning of soldiers,the Holocaust,and the hardships of life.展开更多
The rapid evolution of the political,economic,and social landscape has generated increased interest in understanding the contextual application of management styles and behaviours toward employees.In this context,orga...The rapid evolution of the political,economic,and social landscape has generated increased interest in understanding the contextual application of management styles and behaviours toward employees.In this context,organizations must comprehend and assess employee satisfaction to enhance productivity and realize their strategic and economic goals.Therefore,this study aims to investigate the prevailing and significant management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.To achieve the research objective,the study will employ a qualitative method to explore management behaviours toward employees.Data were collected through interviews with randomly selected managers from different companies and departments.The study aims to uncover discrepancies or variations in employee expectations regarding management behaviour.The findings will provide a better understanding of the most prevalent and significant management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.The results will be valuable to management in adopting suitable leadership styles and improving employee satisfaction,leading to increased productivity and organizational performance.The research will contribute to the existing body of knowledge in the field of management and human resource management by providing insights into the impact of management behaviours on employees.It will also offer recommendations to management on how to enhance employee satisfaction and job commitment,leading to improved organizational performance.In conclusion,this study will investigate the prevailing management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.展开更多
Two tetravalent uranium silicate and germanate M_(2)U^(Ⅳ)T_(3)O_(9)(M=K,Cs;T=Si,Ge)crystals were crystalized under inert gas by molten salt flux growth method.K_(2)USi_(3)O_(9)(1)crystallizes in the monoclinic space ...Two tetravalent uranium silicate and germanate M_(2)U^(Ⅳ)T_(3)O_(9)(M=K,Cs;T=Si,Ge)crystals were crystalized under inert gas by molten salt flux growth method.K_(2)USi_(3)O_(9)(1)crystallizes in the monoclinic space group P1_(21)/n1 with lattice parameters a=7.1076?,b=10.4776?,c=12.2957?,γ=120°and V=915.67?^(3).Cs_(2)UGe_(3)O_(9)(2)crystallizes in a hexagonal space group P-6 with lattice constants of a=7.5138?,b=7.5138?,c=11.0114?,γ=120°and V=538.38?^(3).Bond valence calculations indicate tetravalent uranium in both structures,which contain three-membered single-ring T_(3)O_(9)^(6-) trimers.K_(2)USi_(3)O_(9) is the first uranium silicate that contains the Si_(3)O_(9)^(6-) trimers.展开更多
The germanate glass ceramics is a potential candidate material for infrared （IR） dome and window applications. The crystallization mechanism of 20BaO-10Ga2O3-70GeO2 glass was investigated by differential thermal ana...The germanate glass ceramics is a potential candidate material for infrared （IR） dome and window applications. The crystallization mechanism of 20BaO-10Ga2O3-70GeO2 glass was investigated by differential thermal analysis （DTA）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Two different types of phase evolution were found in the early stage of crystallization： （1） the further growth of the microcrystal formed during the slow cooling of glass melt and （2） the glass-in-glass phase separation. The controlled crystatlization was obtained by two-step heat treatment. obtained, with expected thermal and mechanical The middle infrared （MIR）-transparent glass ceramics were improvements.展开更多
We report a ring cavity passively harmonic mode-locked fiber laser using a newly developed thulium- bismuth co-doped fiber （TBF） as a gain medium in conjunction with a carbon nanotube （CNT）-based saturable absorbe...We report a ring cavity passively harmonic mode-locked fiber laser using a newly developed thulium- bismuth co-doped fiber （TBF） as a gain medium in conjunction with a carbon nanotube （CNT）-based saturable absorber. The TBF laser generates a third harmonic mode-locked soliton pulse train with a high repetition rate of 50 MHz and a pulse duration of 1.86 ps. The laser operates at 1 901.6 nm with an average power of 6.6 mW, corresponding to a pulse energy of 0.132 nJ, at a 1 552 nm pump power of 723.3 roW.展开更多
Immediate Past President of International Council of Ophthalmology(ICO);Academician and former Secretary General of Academia Ophthalmologica Internationalis(AOI);Former Chairman of the Scientific Program of the World ...Immediate Past President of International Council of Ophthalmology(ICO);Academician and former Secretary General of Academia Ophthalmologica Internationalis(AOI);Former Chairman of the Scientific Program of the World Congress of Ophthalmology(WOC);Member of the German Academy of Sciences,former President of German Society of Ophthalmology(DOG);Former Executive Vice President of University of Leipzig and Director of the Eye Hospital;Member of the Club Jules Gonin Executive Committee(2000-2006)。展开更多
There is well-documented evidence for an ongoing decline in flying insect biomass.The author briefly summarizes the 26-years of Malaise trap data(Hallmann et al.2017) from German nature reserves.An additional 10-year ...There is well-documented evidence for an ongoing decline in flying insect biomass.The author briefly summarizes the 26-years of Malaise trap data(Hallmann et al.2017) from German nature reserves.An additional 10-year sweep-net study published by Seibold et al.(2019) found an even greater decline in insects on German forests and grasslands.Additional studies are cited that involve a variety of sampling methods and target butterflies,moths,aphids and other insects.Some studies go back to 1968.The results show declines of 28 to 46 percent.展开更多
基金Supported by the National High-Technology Research and Development Program of China under Grant Nos 2013AA031502 and 2014AA041902the National Natural Science Foundation of China under Grant Nos 11174085,51132004,and 51302086+3 种基金the Natural Science Foundation of Guangdong Province under Grant Nos S2011030001349 and S20120011380the China National Funds for Distinguished Young Scientists under Grant No 61325024the Science and Technology Project of Guangdong Province under Grant No 2013B090500028the ’Cross and Cooperative’ Science and Technology Innovation Team Project of Chinese Academy of Sciences under Grant No 2012-119
文摘A compact linearly polarized, low-noise, narrow-linewidth, single-frequency fiber laser at 1950nm is demonstrated. This compact fiber laser is based on a 21-mm-long homemade Tm3＋-doped germanate glass fiber. Over 100-mW stable continuous-wave single transverse and longitudinal mode lasing at 195Ohm are achieved. The measured relative intensity noise is less than -135dB/Hz at frequencies over 5 MHz. The signal-to-noise ratio of the laser is larger than 72dB, and the laser linewidth is less than 6kHz, while the obtained linear polarization extinction ratio is higher than 22 dB.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51132004 and 61475047the National Basic Research Program of China under Grant No 2011CB808100+2 种基金the Natural Science Foundation of Guangdong Province under Grant No S2011030001349the Fundamental Research Funds for the Central Universities under Grant No 2013ZM0001the Open Fund of the State Key Laboratory of High Field Laser Physics of Shanghai Institute of Optics and Fine Mechanics
文摘We report the observation of bubble generation and migration in a germanate g/ass during irradiation by a femtosecond laser of high repetition rate. Bubbles are formed around the focal area of the laser beam, and their movement indicates the presence of thermal gravity convection in the glass melt, which is beyond the existing theoretical model about temperature l^eld of focal area. Inside the bubbles, oxygen molecules are observed by the con focal Raman micro-spectroscopy. The generation of molecular oxygen and bubbles is explained in terms of the spatial separation of Ge and 0 ions and micro-explosion inside the glass melt.
基金supported by the National Natural Science Foundation of China (Grant 60777030)the Open Foundation of the Key Laboratory of Ningbo City (2007A22010) K.C.Wong Magna Fund in Ningbo University
文摘Two kinds of germanate glasses singly doped with the ion concentration of 2.0mol.%Tm3＋ and 2.0mol.%Ho3＋, respectively, were prepared.According to McCumber theory, the absorption and stimulated emission cross-sections corresponding to the 3H6←→3F4 transitions of Tm3＋（at 1.8 μm） and the 5I8←→5I7 transitions of Ho3＋（at 2.0 μm） were obtained, and respective gain cross-section spectra were also computed as a function of population inversion according to absorption and emission cross-sections and the ion concentrations.For Tm3＋-doped germanate glasses, the maximum of the absorption, emission, and gain cross-sections reached a value higher than those reported for fluorozirconate, fluoride, and oxyfluoride glasses.For Ho3＋-doped germanate glasses, the maximum of absorption, emission, and gain cross-sections reached a value higher than that reported for fluorozircoaluminate glasses.Hence, these Tm3＋-doped and Ho3＋-doped germanate glasses exhibited an advantage for application in mid-infrared lasers at about 1.8 and 2.0 μm wavelength.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars(No.20071108)the National Natural Science Foundation of China(No.20701023)
文摘A layered zirconogermanate, （H2DETA）[ZrGe3O8F2]（1）, was hydro（solvo）thermally synthesized with diethylenetriamine（DETA） as template, and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallized in the monoclinic space group P21/c with data of unit cell： a=0.7644（2） nm, b=1.1235（2） nm, c=1.6860（3） nm, V=1.4479（5） nm^3,/a（Mo Ka）=6.931 mm^-1, Z=4, R1=0.0402 for 3236 reflections with Fo〉2σ（Fo）. The structure of compound I was formed by alternatively packing the inorganic layer of ZrGe3O8F2 and H2DETA templated molecules along （001） direction. It was worth pointing out that the odd bifurcated 7MR nets were surrounded by odd 3MR. The protonated and disordered H2DETA cations not only balanced the superfluous charges of framework but also stabilized the structure of compound 1 by the hydrogen bond between -NH3 group and oxygen on the framework. Furthermore, IR and TG were utilized to characterize the structure and thermal stability, respectively.
基金supported by China National Funds for Guangdong Key Research and Development Program(Grant No.2018B090904001)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(Grant No.2017BT01X137)+2 种基金Key Laboratory of Laser Device Technology Foundation of China Ordnance Industry Group Co.(Grant No.KLLDT202010)the Key R&D Program of Guangzhou(Grant No.202007020003)the National Natural Science Foundation of China(Grant No.52002131)。
文摘Effects of Nb_(2)O_(5)dopant on the radiation response of barium gallo-germanate(BGG)glass are studied mainly by electron paramagnetic resonance and absorption spectroscopy.Owing to the Nb^(5+)$Nb^(3+)interconversion in doped samples,formations of Ge-related non-bridging oxygen hole center and Ge-related electron center defects after g-ray irradiation are inhibited.Thereby,Nb_(2)O_(5)dopant can enhance radiation resistance of BGG glass,and 1.0%Nb2O5 concentration is the best.
文摘A novel gallium germanate (83/2 Na2O . 1/2 Ga2O3 . 24 GeO2) was synthsized by a sol-gel method and hydrothermal crystallization. The germanate was characterized with scanning electron microscopy, electronic energy spectrum, inductively couple plasma-emission spectrum and powder X-ray diffraction. The properties of crystal appearance, size, thermal stability and melting point were studied as well as some influence factors on synthesis process.
文摘A novel indium germanate (183/2Na 2O·1/2In 2O 3·28GeO 2) was synthesized by a sol gel and hydrothermal crystallization. The germanate was characterized with scanning electronic microscopy, electronic energy spectrum, inductively couple plasma emission spectrum and powder X ray diffraction. The properties on its crystal appearance, size, thermal stability and melting point, and some influent factors on synthesis were studied.
基金supported by the National Key R&D Program of China(No.2021YFB2800500)the Research Program of Zhejiang Lab(No.113014-AC2101)+1 种基金the National Natural Science Foundation of China(Nos.51872095,U20A20211,and 62105297)the Zhejiang Provincial Natural Science Foundation(Nos.LQ22A040011 and LZ23F050002)。
文摘Bismuth(Bi)-doped near-infared(NIR)glass that can cover the entire optical communication window(850,1310,and1550 nm)has become the subject of extensive research for developing photonic devices,particularly,tunable fiber lasers and ultrabroadband optical amplifiers.However,the realization of highly efficient NIR luminescence from Bi-doped glass is still full of challenges.Notably,due to the co-existence of multiple Bi NIR centers in the glass,the origin of newly generated Bi NIR emission peaks at~930 and~1520 nm is still controversial.Here,we report a new Bi-doped nitridated germanate glass with tunable ultrabroadband NIR emission(850–1700 nm)and high external quantum efficiency(EQE)of~50%.A series of studies,including spectral analysis,nuclear magnetic resonance(NMR),and others,provide powerful evidence for the mechanism of luminescence enhancement and tunability,and make reasonable inferences about the origin of the new emission bands at~930 and~1520 nm.We believe that the results discussed above would enrich our understanding about multiple Bi NIR emission behaviors and contribute to the design and fabrication of highly efficient Bi-doped ultrabroadband wavelength-tunable optical glass fiber amplifiers and lasers in the future.
基金supported by the National Natural Science Foundation of China(Nos.51172252 and 61177083)
文摘Emission enhancement at 2.7 μm is observed in Er^3＋/Pr^3＋--codoped germanate glasses when pumped by a 980-nm laser diode. Significant reductions in 1.5-μm emission and upeonversion intensity indicate efficient energy transfer between Er^3＋ and Pr^3＋; the energy transfer efficiency is as high as 77.4%. The mechanisms of energy transfer are discussed in detail. The calculated emission cross-section of Er^3＋/Pr^3＋- codoped germanate glass is 8.44× 10 ^-21 cm^2, which suggests that Er^3＋/Pr^3＋-codoped germanate glass can be used to achieve efficient 2.7-μm emission.
基金supported by the National Key Research and Development Plan(No.2017YFF0104504)the National Natural Science Foundation of China(Nos.51672085 and 51322208)+2 种基金the Program for Innovative Research Team in University of Ministry of Education of China(No.IRT_17R38)the Key Program of Guangzhou Scientific Research Special Project(No.201607020009)the Fundamental Research Funds for the Central Universities
文摘Bismuth （Bi）-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reach. Current Bi-dopcd silica glass fibers have to be made by modified chemical vapor deposition at a temperature higher than 2000℃. This unavoidably leads to the tremendous loss of Bi by evaporation, since the temperature is several hundred degrees Celsius higher than the Bi boiling temperature, and, therefore, trace Bi （-50 ppm） resides within the final product of silica fiber. So, the gain of such fiber is usually extremely low. One of the solutions is to make the fibers at a temperature much lower than the boiling temperature of Bi. The challenge for this is to find a lower melting point glass, which can stabilize Bi in the near infrared emission center and, meanwhile, does not lose glass transparency during fiber fabrication. None of previously reported Bi-doped multicomponent glasses can meet the prerequisite. Here, we, after hundreds of trials on optimization over glass components, activator content, melting temperature, etc., find a novel Bi-doped gallogermanate glass, which shows good tolerance to thermal impact and can accommodate a higher content of Bi. Consequently, we successfully manu- facture the germanate fiber by a rod-in-tube technique at 850℃. The fiber exhibits similar luminescence to the bulk glass, and it shows saturated absorption at 808 nm rather than 980 nm as the incident power becomes higher than 4 W. Amplified spontaneous emissions are observed upon the pumps of either 980 or 1064 nm from ger- manate fiber.
基金partly funded by the Clinician-Scientist grant(No.472-0-0)by the medical faculty of the University of Tübingen(to SCV).
文摘Ambroxol hydrochloride(2-amino-3,5-dibromo-N-methylbenzylamine hydrochloride)has been used as a mucolytic agent in the treatment of respiratory diseases since the late 1970s.Its effects on mucus membranes such as mucus disruption,increased mucus production,and low toxicity profile were addressed in its original German patent in 1966.These first described properties have kept Ambroxol available worldwide and over the counter in the pharmaceutical market to this day.
文摘“Europe has missed this development opportunity because we are short of a long-term vision.”MORE than 40 exhibitors from 15 major vehicle brands around the world,representing the latest cutting-edge technologies and models,gathered at the seventh China International Import Expo(CIIE),which was held in Shanghai from November 5 to 10.
文摘In this exclusive interview,Michael Schumann,chairman of the Board of the German Federal Association for Economic Development and Foreign Trade,discusses Sino-German trade relations and the“out-of-proportion”debate on Xinjiang.
文摘The research paper explores belongingness and identity in post-WWII German literature through the lens of iconic scholars,including Wolf,Şenocak,and Grass.The three authors are central and prominent figures in building German literature in the aftermath of the war.National divisions in Germany,rebuilding destroyed communities,and guilt struggles marked this literature.German authors utilized literature during the war to question and comprehend fractures,structures,and the comprehensive identity of a nation with issues of guilt,war,splitting,differences,and divisions.By comprehensively linking Wolf and Grass’authorships to modern debates on multiculturism and migration,we derive fundamental insights and ideas into their applicability to issues affecting our world today.Some of the contemporary issues are immigration,civil wars,and trauma affecting people.Authors like Grass had a significant role to play during post-WWII in Germany,like dealing with and handling migrant and refugee experiences,returning of soldiers,the Holocaust,and the hardships of life.
文摘The rapid evolution of the political,economic,and social landscape has generated increased interest in understanding the contextual application of management styles and behaviours toward employees.In this context,organizations must comprehend and assess employee satisfaction to enhance productivity and realize their strategic and economic goals.Therefore,this study aims to investigate the prevailing and significant management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.To achieve the research objective,the study will employ a qualitative method to explore management behaviours toward employees.Data were collected through interviews with randomly selected managers from different companies and departments.The study aims to uncover discrepancies or variations in employee expectations regarding management behaviour.The findings will provide a better understanding of the most prevalent and significant management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.The results will be valuable to management in adopting suitable leadership styles and improving employee satisfaction,leading to increased productivity and organizational performance.The research will contribute to the existing body of knowledge in the field of management and human resource management by providing insights into the impact of management behaviours on employees.It will also offer recommendations to management on how to enhance employee satisfaction and job commitment,leading to improved organizational performance.In conclusion,this study will investigate the prevailing management behaviours toward employees in large German companies and their impact on employee satisfaction and job commitment.
基金supported by the National Science Fund for Young Scholars(No.22106165)the National Science Fund for Distinguished Young Scholars(No.21925603)+1 种基金the Major Program of the National Natural Science Foundation of China(No.21790373)the National Natural Science Foundation of China(No.U20B2020)。
文摘Two tetravalent uranium silicate and germanate M_(2)U^(Ⅳ)T_(3)O_(9)(M=K,Cs;T=Si,Ge)crystals were crystalized under inert gas by molten salt flux growth method.K_(2)USi_(3)O_(9)(1)crystallizes in the monoclinic space group P1_(21)/n1 with lattice parameters a=7.1076?,b=10.4776?,c=12.2957?,γ=120°and V=915.67?^(3).Cs_(2)UGe_(3)O_(9)(2)crystallizes in a hexagonal space group P-6 with lattice constants of a=7.5138?,b=7.5138?,c=11.0114?,γ=120°and V=538.38?^(3).Bond valence calculations indicate tetravalent uranium in both structures,which contain three-membered single-ring T_(3)O_(9)^(6-) trimers.K_(2)USi_(3)O_(9) is the first uranium silicate that contains the Si_(3)O_(9)^(6-) trimers.
基金supports from Shanghai Pujiang Program and the Hundred of Talents Pragram of Chinese Academy of Sciences are gratefully acknowledged
文摘The germanate glass ceramics is a potential candidate material for infrared （IR） dome and window applications. The crystallization mechanism of 20BaO-10Ga2O3-70GeO2 glass was investigated by differential thermal analysis （DTA）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. Two different types of phase evolution were found in the early stage of crystallization： （1） the further growth of the microcrystal formed during the slow cooling of glass melt and （2） the glass-in-glass phase separation. The controlled crystatlization was obtained by two-step heat treatment. obtained, with expected thermal and mechanical The middle infrared （MIR）-transparent glass ceramics were improvements.
基金supported by Ministry of Higher Education (MOHE) under the Exploratory Research GrantScheme (ERGS) (No. ER012-2012A)the University of Malaya under a Pangurusan Penyelidikan Pascasiswazah (PPP) Grant (No. PV030/2012A)
文摘We report a ring cavity passively harmonic mode-locked fiber laser using a newly developed thulium- bismuth co-doped fiber （TBF） as a gain medium in conjunction with a carbon nanotube （CNT）-based saturable absorber. The TBF laser generates a third harmonic mode-locked soliton pulse train with a high repetition rate of 50 MHz and a pulse duration of 1.86 ps. The laser operates at 1 901.6 nm with an average power of 6.6 mW, corresponding to a pulse energy of 0.132 nJ, at a 1 552 nm pump power of 723.3 roW.
文摘Immediate Past President of International Council of Ophthalmology(ICO);Academician and former Secretary General of Academia Ophthalmologica Internationalis(AOI);Former Chairman of the Scientific Program of the World Congress of Ophthalmology(WOC);Member of the German Academy of Sciences,former President of German Society of Ophthalmology(DOG);Former Executive Vice President of University of Leipzig and Director of the Eye Hospital;Member of the Club Jules Gonin Executive Committee(2000-2006)。
文摘There is well-documented evidence for an ongoing decline in flying insect biomass.The author briefly summarizes the 26-years of Malaise trap data(Hallmann et al.2017) from German nature reserves.An additional 10-year sweep-net study published by Seibold et al.(2019) found an even greater decline in insects on German forests and grasslands.Additional studies are cited that involve a variety of sampling methods and target butterflies,moths,aphids and other insects.Some studies go back to 1968.The results show declines of 28 to 46 percent.
