The Suizhou meteorite is a heavily shocked and melted vein-containing L6 chondrite.It contains a minor amount of diopside with a(Ca_(0.419)Mg_(0.466)Fe_(0.088))SiO_(3)composition,and a shock-metamorphosed diopside gra...The Suizhou meteorite is a heavily shocked and melted vein-containing L6 chondrite.It contains a minor amount of diopside with a(Ca_(0.419)Mg_(0.466)Fe_(0.088))SiO_(3)composition,and a shock-metamorphosed diopside grain associated with ringwoodite and lingunite was found in a melt vein of this meteorite.Our electron microprobe,transmission electron microscopic and Raman spectroscopic analyses revealed four silicate phases with different compositions and structures inside this shock-metamorphosed diopside grain,termed phase A,B,C and D in this paper.Phase A is identified as orthorhombic(Ca_(0.663)-Mg_(0.314))SiO_(3)-perovskite which is closely associated with phase B,the vitrified(Mg_(0.642)Ca_(0.290)Fe_(0.098))SiO_(3)perovskite.Phase D is assigned to be(Mg_(0.578)Ca_(0.414))SiO_(3)majorite which is associated with phase C,the vetrified Carich Mg-perovskite with a(Mg_(0.853)Ca_(0.167))SiO_(3)composition.Based on high-pressure and high-temperature experiments,the diopside grain in the melt vein of the Suizhou meteorite would have experienced a P–T regime of 20–24GPa and 1800–>2000℃.Such P–T conditions are high enough for the decomposition of the diopside and the formation of four different silicate phases.The orthorhombic(Ca_(0.663)Mg_(0.314))SiO_(3)perovskite found in the Suizhou L6 chondrite might be considered as the third lower-mantle silicate mineral after bridgmanite and davemaoite after the detailed analyses of its crystal structure and physical properties being completed.展开更多
Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission sp...Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.展开更多
A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distorti...A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distortion method, and their response time and exponential gain coefficient were tested by two-beam coupling experiment. Besides, the effective carrier concentration has been calculated. The results showed that the absorption edges of reduced and oxidized crystals are respectively shifted to violet and Einstein compared with those of the growth state crystal. From oxidation state to growth state to reduction state of the samples, the photo scattering resistance ability and response time decrease while the exponential gain coefficient and concentration of effective carriers increase. The reduction treatment was necessary for the Mg：In：Fe：LiNbO3 crystals to enhance their photorefractive properties.展开更多
The ability of Li-rich LiNbO3:Mg(5mol%):Fe(0.lwt%)to resist photorefraction is found to be comparable to that of LiNbO3:Mg(5mol%),even though the photorefraction sensitive dopant Fe is added.The nuclear quadrupole spl...The ability of Li-rich LiNbO3:Mg(5mol%):Fe(0.lwt%)to resist photorefraction is found to be comparable to that of LiNbO3:Mg(5mol%),even though the photorefraction sensitive dopant Fe is added.The nuclear quadrupole splitting and isomer shift of 57Fe in Li-rich LiNbO3:Mg57Fe and LiNbO3:57Fe are quite different.The electron spin resonance spectra of the two kinds of crystals are significantly different,too.The enhanced resistance to photorefraction may be due to the change in occupation sites of Fe ions.展开更多
文摘The Suizhou meteorite is a heavily shocked and melted vein-containing L6 chondrite.It contains a minor amount of diopside with a(Ca_(0.419)Mg_(0.466)Fe_(0.088))SiO_(3)composition,and a shock-metamorphosed diopside grain associated with ringwoodite and lingunite was found in a melt vein of this meteorite.Our electron microprobe,transmission electron microscopic and Raman spectroscopic analyses revealed four silicate phases with different compositions and structures inside this shock-metamorphosed diopside grain,termed phase A,B,C and D in this paper.Phase A is identified as orthorhombic(Ca_(0.663)-Mg_(0.314))SiO_(3)-perovskite which is closely associated with phase B,the vitrified(Mg_(0.642)Ca_(0.290)Fe_(0.098))SiO_(3)perovskite.Phase D is assigned to be(Mg_(0.578)Ca_(0.414))SiO_(3)majorite which is associated with phase C,the vetrified Carich Mg-perovskite with a(Mg_(0.853)Ca_(0.167))SiO_(3)composition.Based on high-pressure and high-temperature experiments,the diopside grain in the melt vein of the Suizhou meteorite would have experienced a P–T regime of 20–24GPa and 1800–>2000℃.Such P–T conditions are high enough for the decomposition of the diopside and the formation of four different silicate phases.The orthorhombic(Ca_(0.663)Mg_(0.314))SiO_(3)perovskite found in the Suizhou L6 chondrite might be considered as the third lower-mantle silicate mineral after bridgmanite and davemaoite after the detailed analyses of its crystal structure and physical properties being completed.
文摘在 Fe∶Li Nb O3 中掺进 3 mol%和 6mol% Mg O,生长了 Mg∶Fe∶L i Nb O3 晶体 .测试了 Mg∶Fe∶Li Nb O3 晶体抗光致散射能力、衍射效率、响应时间和光电导 .推导响应时间与光电导之间的关系 .在 Fe∶Li Nb O3 晶体中掺进 6mol%的 Mg2 + ,它的抗光致散射能力比Fe∶L i Nb O3 晶体提高一个数量级 ,响应速度比 Fe∶Li Nb O3
基金Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. DL12AB03)the National Natural Science Founda-tion of China (Grant No. 60777006)
文摘Mg：Ru：Fe：LiN-bO3 crystals with various concentrations of MgO （in mole） and fixed content of RuO2 and Fe203 （in mass） are grown with the Czochralski method from the congruent melt. Their infrared transmission spectra are mea- sured and discussed to investigate the defect structure. With the increase of Mg2＋ concentration the blue nonvolatile holographic storage capability is enhanced. The nonvolatile holographic storage properties of dual-wavelength recording of Mg（7 mol%）：Ru：Fe：LiNbO3 nonvolatile diffraction efficiency, response time, and nonvolatile sensitivity reach 59.8%, 70 s, and 1.04 cm/J, respectively. Comparing Mg（7 mol%）：Ru：Fe：LiNbO3 with Ru：Fe：LiNbO3 crystal, the response time is shortened apparently. The nonvolatile diffraction efficiency and sensitivity are raised largely. The mechanism in blue photorefractive nonvolatile holographic storage is discussed.
基金This work was supported by the Harbin Science and Technic Project (No. 2005AA5CG058)
文摘A series of Mg：In：Fe：LiNbO3 crystals were grown by Czochralski technique; their absorption spectra and photo scattering resistance ability after oxidation or reduction treatment were measured by light spot distortion method, and their response time and exponential gain coefficient were tested by two-beam coupling experiment. Besides, the effective carrier concentration has been calculated. The results showed that the absorption edges of reduced and oxidized crystals are respectively shifted to violet and Einstein compared with those of the growth state crystal. From oxidation state to growth state to reduction state of the samples, the photo scattering resistance ability and response time decrease while the exponential gain coefficient and concentration of effective carriers increase. The reduction treatment was necessary for the Mg：In：Fe：LiNbO3 crystals to enhance their photorefractive properties.
基金Project supported by the National Natural Science Fund of China.
文摘The ability of Li-rich LiNbO3:Mg(5mol%):Fe(0.lwt%)to resist photorefraction is found to be comparable to that of LiNbO3:Mg(5mol%),even though the photorefraction sensitive dopant Fe is added.The nuclear quadrupole splitting and isomer shift of 57Fe in Li-rich LiNbO3:Mg57Fe and LiNbO3:57Fe are quite different.The electron spin resonance spectra of the two kinds of crystals are significantly different,too.The enhanced resistance to photorefraction may be due to the change in occupation sites of Fe ions.
