Tunable All-optical Wavelength Conversion of a Femtosecond Pulse Based on Cascaded (2) SHG + DFG Interactions

Yuping Chen,Feng Lu,Wenjie Lu,Xianfeng Chen 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.3

Based on cascaded second harmonic generation and difference-frequency generation interactions and employing a type-I quasi-phase-matching technique in MgO-doped periodically poled lithium niobate, we realized wavelength conversion of a 70-femtosecond pulse without pulse broadening at the group-velocity-matching wavelength. Due to the 25 nm bandwidth of second harmonic generation obtained in a 20-mm-long crystal, we convert a 70-fs pulse centered at 1.56 μm by using a continuous-wave signal at 1.60 μm. No obvious distortion or broadening of the converted pulse was observed. Based on cascaded second harmonic generation and difference-frequency generation interactions and employing a type-I quasi-phase-matching technique in MgO-doped periodically poled lithium niobate, we realized wavelength conversion of a 70-femtosecond pulse without pulse broadening at the group-velocity-matching wavelength. Due to the 25 nm bandwidth of second harmonic generation obtained in a 20-mm-long crystal, we convert a 70-fs pulse centered at 1.56 μm by using a continuous-wave signal at 1.60 μm. No obvious distortion or broadening of the converted pulse was observed.

Electro-Optics and Its Applications in Domain-Inverted Optical Superlattice

Lijun Chen,Xianfeng Chen,Jianhong hi,Yuping Chen,Yuxing Xia 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.2

We demonstrate an electro-optic ˇSolc-type wavelength filter in periodically poled lithium niobate (PPLN). ˇSolc-type transmission spectrum is observed experimentally in a PPLN with four periods from 20.2 μm to 20.8 μm. Modulation of transmission power of the filter can be realized by applying electric fields along Y -axis of PPLN. It is observed that the wavelength can also be tuned by temperature. Furthermore, we report on a theoretical analysis for the narrowband multiplewavelength filter in aperiodic optical superlattice (AOS). The sequences of the opposite domains in AOS are optimized to realize the prescribed multiple-wavelength filtering by using a simulatedannealing (SA) algorithm. The influences of domain errors, as well as the working temperature, on the performance of the filters are also studied.

Molecular dynamics study on mechanical properties of C-S-H composites

Xianfeng Wang,Peng Wei,Rui Han,Wei Xie,Taoran Li,Dawang Li,Yonggang Peng,Zhen Chen,Feng Xing 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.S1

In this paper, the mechanical properties of calcium silicate hydrate gel (C-S-H) are investigated with molecular dynamics (MD)simulations, in which the Tobermorite 9Å, Tobermorite 11Å, Tobermorite 14Å and Jennite crystals are treated as fundamentalmodels of the C-S-H nanostructure. The initial structures of the crystal models are firstly preprocessed and optimized, andthen are simulated in the canonical (NVT) ensemble conditions. The orthotropic elastic constants of the C-S-H nanostructureare determined and used to derive the bulk and shear moduli via the Voigt-Reuss-Hill method. The self-consistent, Mori-Tanaka, and Voigt methods are employed to compute the mechanical properties of various mixtures of C-S-H composites withdifferent porosities. The simulated results are found to be in a reasonable agreement with those obtained from nanoindentationtests, while the result obtained from the Mori-Tanaka method appears to be the closest to the experimental one. It could also be observed that the mechanical properties of C-S-H vary within a certain range as the porosity and proportionsof the components change.

Novel Nucleotide Variations, Haplotypes Structure and Associations with Growth Related Traits of Goat AT Motif-Binding Factor (ATBF1) Gene

Xiaoyan Zhang,Xianfeng Wu,Wenchao Jia,Chuanying Pan,Xiangcheng Li,Chuzhao Lei,Hong Chen,Xianyong Lan 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.10

The AT motif-binding factor (ATBF1) not only interacts with protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) to suppress STAT3 signaling regulating embryo early development and cell differentiation, but is required for early activation of the pituitary specific transcription factor 1 (Pit1) gene (also known as POU1F1) critically affecting mammalian growth and development. The goal of this study was to detect novel nucleotide variations and haplotypes structure of the ATBF1 gene, as well as to test their associations with growth-related traits in goats. Herein, a total of seven novel single nucleotide polymorphisms (SNPs) (SNP 1-7) within this gene were found in two well-known Chinese native goat breeds. Haplotypes structure analysis demonstrated that there were four haplotypes in Hainan black goat while seventeen haplotypes in Xinong Saanen dairy goat, and both breeds only shared one haplotype (hap1). Association testing revealed that the SNP2, SNP5, SNP6, and SNP7 loci were also found to significantly associate with growth-related traits in goats, respectively. Moreover, one diplotype in Xinong Saanen dairy goats significantly linked to growth related traits. These preliminary findings not only would extend the spectrum of genetic variations of the goat ATBF1 gene, but also would contribute to implementing marker-assisted selection in genetics and breeding in goats.

Variation of resistance and susceptibility in wheat cultivars to different populations of Rhopalosiphum padi (Hemiptera: Aphididae) in China

Meng Zhang,Xianfeng Qiao,Xiong Peng,Maohua Chen 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

The bird cherry-oat aphid, Rhopalosiphumpadi (L.) (Hemiptera: Aphididae), is an important pest insect ofwheat, Triticum aestivum (L.), in China. The susceptibility and resistance of wheat cultivars to different populations of R. padi have been rarely reported. In the current study, eight R. padi populations were collected from different provinces of China, the resistance or susceptibility of six wheat cultivars (Emai 596, Emai 18, Emai 251, Zhengmai 98, Xanthus and 35A9B) to these eight populations was tested by the ratio of aphid abundance according the standard method previously reported. The results showed that R. padi populations from Lanzhou of Gansu Province and Taian of Shandong Province showed similar pattern of aphid-host reactions among the six wheat cultivars. Populations from Nanyang of Henan Province and Baicheng of Jilin Province shared a different pattern of reaction. The respective populations from Xianyang of Shaaxi Privince, Beibei of Chongqing Province, Hongtong of Shanxi Province and Baoding of Hebei Province showed unique resistance/susceptible patterns of aphid-host reactions from other populations. The variability in the response to wheat cultivars to R. padi indicated the existence of biotypic variation in populations. The weight of adult aphid survivors of different populations varied on six wheat cultivars, but did not correspond well to the susceptibility and resistance of wheat cultivars. Our findings are important for the sustainable control of R. padi in different wheat growing regions of China.

Observation of Second Harmonic Generation in Magnetic Fluid Film With an Applied Magnetic Field

Yao Kou,Xianfeng Chen 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Experimental Investigations on VIV of Bridge Deck Sections: A Case Study

Zeng-shun Chen,Si-meng Liu,Xianfeng Yu,Cun-ming Ma,Lei Liu 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.7

In this paper, the Vortex Induced Vibrations (VIVs) of bridge deck sections of the Hong Kong-Zhuhai-Macao Bridge were investigated experimentally. Aeroelastic tests for the bridge deck of two scale ratios (1:20 model and 1:50 model) under different wind attack angles, wind speeds, and damping ratios were performed. Accessory and windbreak effects on the VIVs of the bridge deck were also carried out. The experimental results show that the accessory and windbreak tend to enlarge the VIVs of the bridge deck. Furthermore, the most unfavorable wind attack angle is 5o. At this attack angle and low damping ratios, the VIVs of the bridge deck are significant and much larger than the allowable value. In addition, the VIVs of the bridge deck decrease with increasing the damping ratios (Particularly, at large damping ratios, the VIVs were well suppressed). This study provides a guideline for the designs of long span flexible bridges on suppressing the VIVs of the bridges.

Fabrication and Characterization of Copper-Exchanged BK7 Waveguides

Lei Huang,Xianfeng Chen,Yong Yang,Yuxing Xia 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

In this paper, we report fabrication of a copper-exchanged optical planar waveguide in BK7 glass by using ion exchange with ZnCl$_2$+Cu$_2$Cl$_2$ as ion source. The measured loss of the fabricated waveguides was as low as about 0.36 db/cm. The waveguides can hold 2 -- 4 modes with 5- to 30-minute exchange and 1 mode with 2- or 3-minute exchanges. The effective refractive index of each mode was determined by using the m-line test system at a wavelength of 0.65 $\mu$m. In addition, the cubic spline function interpolation method was employed to recover the gradient refractive index profiles of the copper-containing waveguides. The study on the annealing process for copper-exchanged waveguide is also discussed

Pulse Compression by Difference-Frequency Generation with Engineered Aperiodic Optical Superlattic

Y. Kong,Xianfeng Chen,P. Li,Y. Xia 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.II

We theoretically propose a procedure for designing quasi-phase-matching (QPM) gratings for compressing ultrashort optical pulses during difference-frequency generation. The grating consists of blocks of crystal with the same block length and the direction of spontaneous polarization of each block is determined by an optimal algorithm through which the sign of the nonlinear coefficient of each block is optimized to make the phase response of the grating the same for different wavelengths of the output idler waves so that the generated idler pulse from the end of the crystal will be compressed during difference-frequency generation. Pumped by a cw (or a quasi-cw) laser, the generated idler pulse is compressed beyond its Fourier-transform limit in the simulations

Novel Nucleotide Variations, Haplotypes Structure and Associations with Growth Related Traits of Goat AT Motif-Binding Factor (ATBF1) Gene

Zhang, Xiaoyan,Wu, Xianfeng,Jia, Wenchao,Pan, Chuanying,Li, Xiangcheng,Lei, Chuzhao,Chen, Hong,Lan, Xianyong Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.10

The AT motif-binding factor (ATBF1) not only interacts with protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) to suppress STAT3 signaling regulating embryo early development and cell differentiation, but is required for early activation of the pituitary specific transcription factor 1 (Pit1) gene (also known as POU1F1) critically affecting mammalian growth and development. The goal of this study was to detect novel nucleotide variations and haplotypes structure of the ATBF1 gene, as well as to test their associations with growth-related traits in goats. Herein, a total of seven novel single nucleotide polymorphisms (SNPs) (SNP 1-7) within this gene were found in two well-known Chinese native goat breeds. Haplotypes structure analysis demonstrated that there were four haplotypes in Hainan black goat while seventeen haplotypes in Xinong Saanen dairy goat, and both breeds only shared one haplotype (hap1). Association testing revealed that the SNP2, SNP5, SNP6, and SNP7 loci were also found to significantly associate with growth-related traits in goats, respectively. Moreover, one diplotype in Xinong Saanen dairy goats significantly linked to growth related traits. These preliminary findings not only would extend the spectrum of genetic variations of the goat ATBF1 gene, but also would contribute to implementing marker-assisted selection in genetics and breeding in goats.