With the universal test machine and temperature test chamber, the effect of pressure and temperature on the behavior of 1-3 and 1-3-2 piezocomposites prepared with PZT/epoxy in our lab has been investigated through el...With the universal test machine and temperature test chamber, the effect of pressure and temperature on the behavior of 1-3 and 1-3-2 piezocomposites prepared with PZT/epoxy in our lab has been investigated through electrical impedance and dielectric analysis. The permittivity, resonant frequency and dielectric loss of the composites have been measured under vertical stress and temperature, and the variety of the material properties under pressure and temperature could also be obtained. The pressure and temperature stability of the composites have been assessed through experiments. The data of these two types of composites indicated that the stability of 1-342 composite with pressure was better than that of 1-3 composite, and two composites have almost the same dielectric stability with temperature. However, 1-3-2 composite showed slower frequency variation than 1-3 composite.展开更多
A white emitting phosphor of YAl33(BO3)4:Ce+,Dy3+is synthesized by a solid state reaction,and its luminescent properties are investigated.Its phase formation is carried out with X-ray powder diffraction analysis,and t...A white emitting phosphor of YAl33(BO3)4:Ce+,Dy3+is synthesized by a solid state reaction,and its luminescent properties are investigated.Its phase formation is carried out with X-ray powder diffraction analysis,and there is no crystalline phase other than YAl3(BO3)4.YAl3(BO3)4:Ce3+can produce 422 nm blue emission under 367 nm excitation.The emission spectrum of YAl33(BO3)4:Dy+shows several emission peaks under 350 nm excitation,and the peaks locate at485 nm,575 nm and 668 nm,respectively.Emission intensities of Ce3+and Dy3+in YAl3(BO3)4 are influenced by their concentrations,and the concentration quenching effect is observed.Energy transfer from Ce3+to Dy3+in YAl3(BO3)4 is validated and proved to be a resonant type via a quadrupole-quadrupole interaction,and the emission color can be tuned from blue to white by tuning the ratio of Ce3+/Dy3+.Moreover,the critical distance(Rc)of Ce3+to Dy3+in YAl3(BO3)4 is calculated to be 1.904 nm.展开更多
Blue emitting phosphor SrZn_2(PO_4)_2:Eu^(2+) is synthesized by a high temperature solid state method,and the luminescent properties are investigated.At the 330 nm radiation excitation,SrZn_2(PO_4)_2:Eu^(2+) presents ...Blue emitting phosphor SrZn_2(PO_4)_2:Eu^(2+) is synthesized by a high temperature solid state method,and the luminescent properties are investigated.At the 330 nm radiation excitation,SrZn_2(PO_4)_2:Eu^(2+) presents an emission band at 416 nm,which is assigned to the 4f^65d^1→4f^7 transition of Eu^(2+) ion.The concentration quenching effect of Eu^(2+) in SrZn_2(PO_4)_2has been validated and proved to be a resonant type via a dipole-dipole interaction.The critical distance(R_c) of Eu^(2+) in SrZn_2(PO_4)_2 is calculated to be 3.244 nm.The Commission International de I'Eclairage(CIE) chromaticity coordinates of SrZn_2(PO_4)_2:Eu^(2+) locate at the blue region,such as(0.150,0.072).The results indicate that the SrZn_2(PO_4)_2:Eu^(2+)phosphor may have potential applications in white light emitting diodes(LEDs).展开更多
A series of Ce^(3+),Eu^(2+) and Ce^(3+)-Eu^(2+) doped Ca_9Al(PO_4)_7 phosphors are synthesized by a high temperature solid-state method.Under 291 nm excitation,Ca_9Al(PO_4)_7:Ce^(3+) has one emission band at 356 nm,wh...A series of Ce^(3+),Eu^(2+) and Ce^(3+)-Eu^(2+) doped Ca_9Al(PO_4)_7 phosphors are synthesized by a high temperature solid-state method.Under 291 nm excitation,Ca_9Al(PO_4)_7:Ce^(3+) has one emission band at 356 nm,which is attributed to4f°5d^1→4f^1 transition of Ce^(3+).Under 305 nm excitation,Ca_9Al(PO_4)_7:Eu^(2+) presents one emission band at 445 nm,which is assigned to 4f^65d^1→4f^7 transition of Eu^(2+).Energy transfer from Ce^(3+) to Eu^(2+) in Ca_9Al(PO_4)_7 is validated and proved to be a resonant type via a quadrupole-quadrupole interaction.Critical distance(R_c) of Ce^(3+) to Eu^(2+) in Ca_9Al(PO_4)_7 is calculated to be 1.264 nm.Moreover,the emission intensity of Ca_9Al(PO_4)_7:Ce^(3+),Eu^(2+) can be tuned by properly adjusting the relative doping composition of Ce^(3+)/Eu^(2+).展开更多
The Jamesian style of poise and exquisiteness, and his notion of structural balance and his superb craftsmanship, is bril-liantly exemplified by The Portrait of a Lady, a work to be appreciated endlessly. This paper s...The Jamesian style of poise and exquisiteness, and his notion of structural balance and his superb craftsmanship, is bril-liantly exemplified by The Portrait of a Lady, a work to be appreciated endlessly. This paper studies the artistic genius of HenryJames, as it attains a great height in this early masterpiece.展开更多
A novel white-bluish emitting phosphor of (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ is synthesized by the solid state reaction. (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ can be effectively excited by 370 nm ultraviolet (UV) light, and ex...A novel white-bluish emitting phosphor of (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ is synthesized by the solid state reaction. (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ can be effectively excited by 370 nm ultraviolet (UV) light, and exhibits two emission bands at 430 nm and 522 nm which are attributed to the d-f transitions of the Eu2+ ions in two different cation sites in the host lattices. And the chromaticity coordinate of (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ phosphor is (0.29, 0.25).展开更多
For enhancing the emission intensity and broadening the excitation region of Ba3Eu（PO4）3 （BEP）, Sm3＋ is doped as sensitizer in this paper. BEP：Sm3＋ can produce an obvious red emission at near ultraviolet （n-UV...For enhancing the emission intensity and broadening the excitation region of Ba3Eu（PO4）3 （BEP）, Sm3＋ is doped as sensitizer in this paper. BEP：Sm3＋ can produce an obvious red emission at near ultraviolet （n-UV） radiation. An effec- tive energy transfer from Sm3＋ to Eu3＋ is proved. The commission international de I＇Eclairage （CIE） chromaticity co- ordinates of BEP：Sm3＋ locate at red region. When the environment temperature is 150 ℃, the emission intensity of BEP：0.10Sm3＋ is decreased to 76% of the initial one at room temperaatre, and the activation energy is calculated to be 0.164 eV, which can prove the good thermal stability of BEP：Sm3＋. The results indicate that BEP：Sm3＋ may have po- tential applications in white light emitting diodes （LEDs）.展开更多
A series of Sr3Y(PO4)3:Eu2+ samples are synthesized by the high temperature solid-state method. Sr3Y(PO4)3:Eu2+shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm ar...A series of Sr3Y(PO4)3:Eu2+ samples are synthesized by the high temperature solid-state method. Sr3Y(PO4)3:Eu2+shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm are assigned to the nine-coordination Eu2+ and six-coordination Eu2+, respectively. The effects of Eu2+ doping content on the emission intensity and color are observed, and the concentration quenching effect is also observed. For two different Eu2+ luminescence centers, the quenching mechanisms are dipole-dipole interaction and quadrupole-quadrupole interaction, respectively. And the critical distance of energy transfer is calculated by concentration quenching and turns out to be about 3.67 nm. The results above show that the asymmetrical emission band of Sr3Y(PO4)3:Eu2+ comes from two different Eu2+ luminescence centers in the lattice.展开更多
A series of Tb3+ doped Na Y(Mo O4)2 are synthesized by a solid-state reaction at 550 °C for 4 h, and their luminescent properties are investigated. The phase formation is carried out with X-ray powder diffraction...A series of Tb3+ doped Na Y(Mo O4)2 are synthesized by a solid-state reaction at 550 °C for 4 h, and their luminescent properties are investigated. The phase formation is carried out with X-ray powder diffraction analysis, and there is no other crystalline phase except Na Y(Mo O4)2. Na Y(Mo O4)2:Tb3+ can produce the green emission under 290 nm radiation excitation, and the luminescence emission peak at 545 nm corresponds to the 5D4→7F5 transition of Tb3+. The emission intensity of Tb3+ in Na Y(Mo O4)2 is enhanced with the increase of Tb3+ concentration, and there is no concentration quenching effect. The phenomena are proved by the decay curves of Tb3+. Moreover, the Commission International de I'Eclairage(CIE) chromaticity coordinates of Na Y(Mo O4)2:Tb3+ locate in the green region.展开更多
In this paper, the author explores the significance of reading material to the reading class in terms of the teachers＇ teaching achievement and the improvement in students＇ reading skills. Some common problems with ...In this paper, the author explores the significance of reading material to the reading class in terms of the teachers＇ teaching achievement and the improvement in students＇ reading skills. Some common problems with reading material are presented and some suggestions are provided on how teachers should do with the reading material.展开更多
The story The scarlet letter happened in the later seventeenth century by Hawthorn, when the Puritans had declined in morality. Hawthorne points out that the suffering and agony of the characters in The scarlet letter...The story The scarlet letter happened in the later seventeenth century by Hawthorn, when the Puritans had declined in morality. Hawthorne points out that the suffering and agony of the characters in The scarlet letter is due to an ill-conceived marriage. At the same time Hawthorne lightens the story in that he invents his own moral dimension of marriage and adultery and suggests that marriage should be based on the communion of the souls.展开更多
A series of Eu^(3+) or Tb^(3+) doped Ba_2Ca(BO_3)_2 phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. Ba_2Ca(BO_3)_2:Tb^(3+) can show an obvious gre...A series of Eu^(3+) or Tb^(3+) doped Ba_2Ca(BO_3)_2 phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. Ba_2Ca(BO_3)_2:Tb^(3+) can show an obvious green emission, and the peak locates at 551 nm, which corresponds to the 5D34→7F5 transition of Tb^(3+). Ba_2Ca(BO_3)_2:Eu+ can present the characteristic emission of Eu^(3+), and the peak locates at 600 nm, which is ascribed to the 5D70→F2 transition of Eu^(3+). In order to achieve the emission-tunable phosphors, the Eu^(3+)/Tb^(3+) co-doped Ba_2Ca(BO_3)_2 are synthesized. When tuning the Eu^(3+) or Tb^(3+) concentration, Ba_2Ca(BO_3)_2:Eu^(3+), Tb^(3+) can both show the tunable emission, which may be induced by the energy transfer from Tb^(3+) to Eu^(3+).展开更多
SrZn2(PO4)2:Sm3+ phosphor was synthesized by a high temperature solid-state reaction in atmosphere. SrZn2(PO4)2:Sm3+ phosphor is efficiently excited by ultraviolet(UV) and blue light, and the emission peaks are assign...SrZn2(PO4)2:Sm3+ phosphor was synthesized by a high temperature solid-state reaction in atmosphere. SrZn2(PO4)2:Sm3+ phosphor is efficiently excited by ultraviolet(UV) and blue light, and the emission peaks are assigned to the transitions of 4G5/2-6H5/2(563 nm), 4G5/2-6H7/2(597 nm and 605 nm) and 4G5/2-6H9/2(644 nm and 653 nm). The emission intensities of SrZn2(PO4)2:Sm3+ are influenced by Sm3+ concentration, and the concentration quenching effect of SrZn2(PO4)2:Sm3+ is also observed. When doping A+(A=Li, Na and K) ions, the emission intensity of SrZn2(PO4)2:Sm3+ can be obviously enhanced. The Commission Internationale de l'Eclairage(CIE) color coordinates of SrZn2(PO4)2:Sm3+ locate in the orange-red region. The results indicate that the phosphor has a potential application in white light emitting diodes(LEDs).展开更多
Under the background of the Internet Plus,the research on the online and offline integrated teaching mode is particularly important.Therefore,based on the teaching of Henan Police College and taking the college Englis...Under the background of the Internet Plus,the research on the online and offline integrated teaching mode is particularly important.Therefore,based on the teaching of Henan Police College and taking the college English course as an example,this paper investigates and analyzes the online teaching situation.The results show that there are significant differences between gender and grade in students’online English learning;the biggest difficulty for students in online English learning is the lack of learning materials like textbooks and the simultaneous use of multiple equipment in class;the biggest problem in the ideological and political integration of English course is that the way of ideological and political integration in English class lacks of variety.Through this research,it is hoped to help teachers in HNP college improve the online teaching mode,improve the online teaching quality,and promote the normalization of online and offline teaching mode.展开更多
Based on Winter's and Hoey's theories on discourse analysis, the Problem-Solution Pattern in cosmetic advertising from the perspective of text patterns and lexical signaling is discussed by analyzing thirty pi...Based on Winter's and Hoey's theories on discourse analysis, the Problem-Solution Pattern in cosmetic advertising from the perspective of text patterns and lexical signaling is discussed by analyzing thirty pieces of advertisements on cosmetic products. Findings suggest text patterns of cosmetic advertisements display in various forms and the components of Problem-Solution Pattern are signaled by lexical items as emotive vocabulary with positive or negative meanings and repetition of the brand names. Possible implications are offered for cosmetic advertising industry in writing effective advertisements both in English and Chinese.展开更多
A series of Ce3＋, Tb3＋ or Ce3＋/Tb3＋ doped YA13（BO3）4 phosphors are synthesized by a high temperature solid-state reaction, and their luminescent properties are investigated. YA13（BO3）a：Ce3＋ shows a broad emi...A series of Ce3＋, Tb3＋ or Ce3＋/Tb3＋ doped YA13（BO3）4 phosphors are synthesized by a high temperature solid-state reaction, and their luminescent properties are investigated. YA13（BO3）a：Ce3＋ shows a broad emission band at 422 nm under the 367 nm radiation excitation. YA13（BO3）4：Tb3＋ can be efficiently excited by the ultraviolet （UV） light, and produces green emission. The emission intensity of YA13（BO3）4：Tb3＋ can be enhanced by adjusting Tb3＋ doped content, and reaches the maximum at 0.06 mol Tb3＋. When Ce3＋ is codoped, the emission intensity of Tb3＋ in YA13（BO3）4 can be enhanced, but the commission international del＇eclairage （CIE） chromaticity coordinates of YA13（BO3）4：Tb3＋ have almost no change. Moreover, the energy transfer from Ce3＋ to Tb3＋ in YA13（BO3）4 is studied.展开更多
Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By...Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By analyzing the Chinese way of flouting CP, the author explores the unique characteristics of CP in Chinese context.展开更多
Ethylene is the main factor controlling fruit ripening of pear(Pyrus ussuriensis).Ethylene production rate is negatively correlated with fruit shelf life;therefore,it is important to decrease the ethylene levels for o...Ethylene is the main factor controlling fruit ripening of pear(Pyrus ussuriensis).Ethylene production rate is negatively correlated with fruit shelf life;therefore,it is important to decrease the ethylene levels for optimal fruit storage.Here,we observed that blue light treatment could inhibit ethylene production and promote the expression of ELONGATED HYPOCOTYL 5(PuHY5),a basic leucine zipper domain(bZIP)transcription factor.The following studies showed that PuHY5 could bind to the promoter of ACC synthase 1(PuACS1),a rate-limiting enzyme in ethylene biosynthesis,and inhibit its expression.For pears in which Pu HY5 was silenced,the ethylene production and PuACS1 expression were much higher than those in the control fruit.These results demonstrated that blue light inhibited ethylene production through the induction of Pu HY5 in pear.Our finding provides a new method for prolonging fruit shelf life.展开更多
基金supported by the National Natural Science Foundation of China (No.60871038)the Beijing Natural Science Foundation (No.4092014)Foundation of PHR(IHLB)
文摘With the universal test machine and temperature test chamber, the effect of pressure and temperature on the behavior of 1-3 and 1-3-2 piezocomposites prepared with PZT/epoxy in our lab has been investigated through electrical impedance and dielectric analysis. The permittivity, resonant frequency and dielectric loss of the composites have been measured under vertical stress and temperature, and the variety of the material properties under pressure and temperature could also be obtained. The pressure and temperature stability of the composites have been assessed through experiments. The data of these two types of composites indicated that the stability of 1-342 composite with pressure was better than that of 1-3 composite, and two composites have almost the same dielectric stability with temperature. However, 1-3-2 composite showed slower frequency variation than 1-3 composite.
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province in China(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province in China(Nos.ZD2014036 and QN2014085)
文摘A white emitting phosphor of YAl33(BO3)4:Ce+,Dy3+is synthesized by a solid state reaction,and its luminescent properties are investigated.Its phase formation is carried out with X-ray powder diffraction analysis,and there is no crystalline phase other than YAl3(BO3)4.YAl3(BO3)4:Ce3+can produce 422 nm blue emission under 367 nm excitation.The emission spectrum of YAl33(BO3)4:Dy+shows several emission peaks under 350 nm excitation,and the peaks locate at485 nm,575 nm and 668 nm,respectively.Emission intensities of Ce3+and Dy3+in YAl3(BO3)4 are influenced by their concentrations,and the concentration quenching effect is observed.Energy transfer from Ce3+to Dy3+in YAl3(BO3)4 is validated and proved to be a resonant type via a quadrupole-quadrupole interaction,and the emission color can be tuned from blue to white by tuning the ratio of Ce3+/Dy3+.Moreover,the critical distance(Rc)of Ce3+to Dy3+in YAl3(BO3)4 is calculated to be 1.904 nm.
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province of China(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province of China(Nos.ZD2014036 and QN2014085)
文摘Blue emitting phosphor SrZn_2(PO_4)_2:Eu^(2+) is synthesized by a high temperature solid state method,and the luminescent properties are investigated.At the 330 nm radiation excitation,SrZn_2(PO_4)_2:Eu^(2+) presents an emission band at 416 nm,which is assigned to the 4f^65d^1→4f^7 transition of Eu^(2+) ion.The concentration quenching effect of Eu^(2+) in SrZn_2(PO_4)_2has been validated and proved to be a resonant type via a dipole-dipole interaction.The critical distance(R_c) of Eu^(2+) in SrZn_2(PO_4)_2 is calculated to be 3.244 nm.The Commission International de I'Eclairage(CIE) chromaticity coordinates of SrZn_2(PO_4)_2:Eu^(2+) locate at the blue region,such as(0.150,0.072).The results indicate that the SrZn_2(PO_4)_2:Eu^(2+)phosphor may have potential applications in white light emitting diodes(LEDs).
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation ofHebei Province in China(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province in China(Nos.ZD2014036 and QN2014085)
文摘A series of Ce^(3+),Eu^(2+) and Ce^(3+)-Eu^(2+) doped Ca_9Al(PO_4)_7 phosphors are synthesized by a high temperature solid-state method.Under 291 nm excitation,Ca_9Al(PO_4)_7:Ce^(3+) has one emission band at 356 nm,which is attributed to4f°5d^1→4f^1 transition of Ce^(3+).Under 305 nm excitation,Ca_9Al(PO_4)_7:Eu^(2+) presents one emission band at 445 nm,which is assigned to 4f^65d^1→4f^7 transition of Eu^(2+).Energy transfer from Ce^(3+) to Eu^(2+) in Ca_9Al(PO_4)_7 is validated and proved to be a resonant type via a quadrupole-quadrupole interaction.Critical distance(R_c) of Ce^(3+) to Eu^(2+) in Ca_9Al(PO_4)_7 is calculated to be 1.264 nm.Moreover,the emission intensity of Ca_9Al(PO_4)_7:Ce^(3+),Eu^(2+) can be tuned by properly adjusting the relative doping composition of Ce^(3+)/Eu^(2+).
文摘The Jamesian style of poise and exquisiteness, and his notion of structural balance and his superb craftsmanship, is bril-liantly exemplified by The Portrait of a Lady, a work to be appreciated endlessly. This paper studies the artistic genius of HenryJames, as it attains a great height in this early masterpiece.
基金the Natural Science Foundation of Hebei Province in China (No.D2012201115)
文摘A novel white-bluish emitting phosphor of (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ is synthesized by the solid state reaction. (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ can be effectively excited by 370 nm ultraviolet (UV) light, and exhibits two emission bands at 430 nm and 522 nm which are attributed to the d-f transitions of the Eu2+ ions in two different cation sites in the host lattices. And the chromaticity coordinate of (Ba0.49Sr0.49)2B2P2O10:0.02Eu2+ phosphor is (0.29, 0.25).
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province in China(Nos.A2014201035 and E2014201037)+1 种基金the Education Office Research Foundation of Hebei Province in China(Nos.ZD2014036 and QN2014085)the College Students Innovation and Entrepreneurship of Hebei University in China(Nos.2014041 and 2015063)
文摘For enhancing the emission intensity and broadening the excitation region of Ba3Eu（PO4）3 （BEP）, Sm3＋ is doped as sensitizer in this paper. BEP：Sm3＋ can produce an obvious red emission at near ultraviolet （n-UV） radiation. An effec- tive energy transfer from Sm3＋ to Eu3＋ is proved. The commission international de I＇Eclairage （CIE） chromaticity co- ordinates of BEP：Sm3＋ locate at red region. When the environment temperature is 150 ℃, the emission intensity of BEP：0.10Sm3＋ is decreased to 76% of the initial one at room temperaatre, and the activation energy is calculated to be 0.164 eV, which can prove the good thermal stability of BEP：Sm3＋. The results indicate that BEP：Sm3＋ may have po- tential applications in white light emitting diodes （LEDs）.
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province of China(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province of China(Nos.ZD2014036 and QN2014085)
文摘A series of Sr3Y(PO4)3:Eu2+ samples are synthesized by the high temperature solid-state method. Sr3Y(PO4)3:Eu2+shows an asymmetrical emission band under excitation of 350 nm. The emission peaks at 426 nm and 497 nm are assigned to the nine-coordination Eu2+ and six-coordination Eu2+, respectively. The effects of Eu2+ doping content on the emission intensity and color are observed, and the concentration quenching effect is also observed. For two different Eu2+ luminescence centers, the quenching mechanisms are dipole-dipole interaction and quadrupole-quadrupole interaction, respectively. And the critical distance of energy transfer is calculated by concentration quenching and turns out to be about 3.67 nm. The results above show that the asymmetrical emission band of Sr3Y(PO4)3:Eu2+ comes from two different Eu2+ luminescence centers in the lattice.
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province(Nos.ZD2014036 and QN2014085)
文摘A series of Tb3+ doped Na Y(Mo O4)2 are synthesized by a solid-state reaction at 550 °C for 4 h, and their luminescent properties are investigated. The phase formation is carried out with X-ray powder diffraction analysis, and there is no other crystalline phase except Na Y(Mo O4)2. Na Y(Mo O4)2:Tb3+ can produce the green emission under 290 nm radiation excitation, and the luminescence emission peak at 545 nm corresponds to the 5D4→7F5 transition of Tb3+. The emission intensity of Tb3+ in Na Y(Mo O4)2 is enhanced with the increase of Tb3+ concentration, and there is no concentration quenching effect. The phenomena are proved by the decay curves of Tb3+. Moreover, the Commission International de I'Eclairage(CIE) chromaticity coordinates of Na Y(Mo O4)2:Tb3+ locate in the green region.
文摘In this paper, the author explores the significance of reading material to the reading class in terms of the teachers＇ teaching achievement and the improvement in students＇ reading skills. Some common problems with reading material are presented and some suggestions are provided on how teachers should do with the reading material.
文摘The story The scarlet letter happened in the later seventeenth century by Hawthorn, when the Puritans had declined in morality. Hawthorne points out that the suffering and agony of the characters in The scarlet letter is due to an ill-conceived marriage. At the same time Hawthorne lightens the story in that he invents his own moral dimension of marriage and adultery and suggests that marriage should be based on the communion of the souls.
基金supported by the China Postdoctoral Science Foundation(No.2015M581311)the College Students Innovation and Entrepreneurship of Hebei University in China(Nos.2014041 and 2015063)
文摘A series of Eu^(3+) or Tb^(3+) doped Ba_2Ca(BO_3)_2 phosphors were synthesized by a high temperature solid state method, and the luminescence properties are investigated. Ba_2Ca(BO_3)_2:Tb^(3+) can show an obvious green emission, and the peak locates at 551 nm, which corresponds to the 5D34→7F5 transition of Tb^(3+). Ba_2Ca(BO_3)_2:Eu+ can present the characteristic emission of Eu^(3+), and the peak locates at 600 nm, which is ascribed to the 5D70→F2 transition of Eu^(3+). In order to achieve the emission-tunable phosphors, the Eu^(3+)/Tb^(3+) co-doped Ba_2Ca(BO_3)_2 are synthesized. When tuning the Eu^(3+) or Tb^(3+) concentration, Ba_2Ca(BO_3)_2:Eu^(3+), Tb^(3+) can both show the tunable emission, which may be induced by the energy transfer from Tb^(3+) to Eu^(3+).
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province in China(Nos.A2014201035 and E2014201037)the Education Office Research Foundation of Hebei Province in China(Nos.ZD2014036 and QN2014085)
文摘SrZn2(PO4)2:Sm3+ phosphor was synthesized by a high temperature solid-state reaction in atmosphere. SrZn2(PO4)2:Sm3+ phosphor is efficiently excited by ultraviolet(UV) and blue light, and the emission peaks are assigned to the transitions of 4G5/2-6H5/2(563 nm), 4G5/2-6H7/2(597 nm and 605 nm) and 4G5/2-6H9/2(644 nm and 653 nm). The emission intensities of SrZn2(PO4)2:Sm3+ are influenced by Sm3+ concentration, and the concentration quenching effect of SrZn2(PO4)2:Sm3+ is also observed. When doping A+(A=Li, Na and K) ions, the emission intensity of SrZn2(PO4)2:Sm3+ can be obviously enhanced. The Commission Internationale de l'Eclairage(CIE) color coordinates of SrZn2(PO4)2:Sm3+ locate in the orange-red region. The results indicate that the phosphor has a potential application in white light emitting diodes(LEDs).
文摘Under the background of the Internet Plus,the research on the online and offline integrated teaching mode is particularly important.Therefore,based on the teaching of Henan Police College and taking the college English course as an example,this paper investigates and analyzes the online teaching situation.The results show that there are significant differences between gender and grade in students’online English learning;the biggest difficulty for students in online English learning is the lack of learning materials like textbooks and the simultaneous use of multiple equipment in class;the biggest problem in the ideological and political integration of English course is that the way of ideological and political integration in English class lacks of variety.Through this research,it is hoped to help teachers in HNP college improve the online teaching mode,improve the online teaching quality,and promote the normalization of online and offline teaching mode.
文摘Based on Winter's and Hoey's theories on discourse analysis, the Problem-Solution Pattern in cosmetic advertising from the perspective of text patterns and lexical signaling is discussed by analyzing thirty pieces of advertisements on cosmetic products. Findings suggest text patterns of cosmetic advertisements display in various forms and the components of Problem-Solution Pattern are signaled by lexical items as emotive vocabulary with positive or negative meanings and repetition of the brand names. Possible implications are offered for cosmetic advertising industry in writing effective advertisements both in English and Chinese.
基金This work has been supported by the Natural Science Foundation of Hebei Province in China （Nos.D2012201115 and A2011201010）, the Guide Project of University Science ＆ Technology Research in Hebei Province in China （No.Z2011266）, the Scientific Research Project of Hebei Province Education Department （No.20052021）, and the Guide Project of Bureau of Science and Technology of Baoding in Hebei Province in China （No. 12ZR057）.
文摘A series of Ce3＋, Tb3＋ or Ce3＋/Tb3＋ doped YA13（BO3）4 phosphors are synthesized by a high temperature solid-state reaction, and their luminescent properties are investigated. YA13（BO3）a：Ce3＋ shows a broad emission band at 422 nm under the 367 nm radiation excitation. YA13（BO3）4：Tb3＋ can be efficiently excited by the ultraviolet （UV） light, and produces green emission. The emission intensity of YA13（BO3）4：Tb3＋ can be enhanced by adjusting Tb3＋ doped content, and reaches the maximum at 0.06 mol Tb3＋. When Ce3＋ is codoped, the emission intensity of Tb3＋ in YA13（BO3）4 can be enhanced, but the commission international del＇eclairage （CIE） chromaticity coordinates of YA13（BO3）4：Tb3＋ have almost no change. Moreover, the energy transfer from Ce3＋ to Tb3＋ in YA13（BO3）4 is studied.
文摘Some examples of flouting Cooperative Principle (CP) in Chinese people's greeting, requesting, and accepting compliment are presented and the cultural reasons for these violations are explained in this article. By analyzing the Chinese way of flouting CP, the author explores the unique characteristics of CP in Chinese context.
基金supported by the National Natural Science Foundation of China(Grant Nos.32125034 and 31801834)。
文摘Ethylene is the main factor controlling fruit ripening of pear(Pyrus ussuriensis).Ethylene production rate is negatively correlated with fruit shelf life;therefore,it is important to decrease the ethylene levels for optimal fruit storage.Here,we observed that blue light treatment could inhibit ethylene production and promote the expression of ELONGATED HYPOCOTYL 5(PuHY5),a basic leucine zipper domain(bZIP)transcription factor.The following studies showed that PuHY5 could bind to the promoter of ACC synthase 1(PuACS1),a rate-limiting enzyme in ethylene biosynthesis,and inhibit its expression.For pears in which Pu HY5 was silenced,the ethylene production and PuACS1 expression were much higher than those in the control fruit.These results demonstrated that blue light inhibited ethylene production through the induction of Pu HY5 in pear.Our finding provides a new method for prolonging fruit shelf life.
