http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Anoop Kumar Srivastava,김종윤,여성구,정진영,최이준,SINGHVIJAY,이지훈 한국물리학회 2017 Current Applied Physics Vol.17 No.6
We investigated the dielectric dispersion property of a bent-core liquid crystal (BLC) with a large kink angle in the frequency range of 1.0 Hze5.5 MHz in a planar aligned cell. Single dielectric dispersion was observed in the smectic A, nematic, and isotropic phase of the planar aligned sample. The dielectric strengths, relaxation frequencies, distribution parameters, and dc conductivity were measured as a function of temperature. The dielectric strength of the observed relaxation mode was anomalously high (~70), whereas the relaxation frequency was low at ~500 Hz. The relaxation mode observed in the planar aligned cell was attributed to the fluctuations in the polarization direction due to the cooperative motion of the molecules.
Sunggu Yeo,Anoop Kumar Srivastava,Hyojin Lee,Ji-Hoon Lee,E-Joon Choi 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.2
We investigated the temperature dependences of the dielectric anisotropy, birefringence, order parameter, splay elastic constant, and rotational viscosity of rodlike nematic liquid crystals (RLCs) doped with hockey-stick-shaped liquid crystals (HLCs). Although the order parameter of the HLCRLC mixtures was similar to that of the pure RLC, the dielectric anisotropy and the birefringence of the mixtures were decreased or increased depending on the structure of the HLC molecule. In addition, the activation energies of the mixtures were different, which implies that the intramolecular structure of the HLC molecule had more influence on the electrooptical properties of the HLC-RLC binary mixtures than the inter-molecular interaction between the HLC and the RLC molecules.
전은정,이승희,Anoop Kumar Srivastava,김미영,정광운,최정민,이기동 한국정보디스플레이학회 2009 Journal of information display Vol.10 No.4
As the physical properties of nematic liquid crystals vary with respect to temperature, the performances of liquid crystal displays (LCDs) are highly dependent on temperature. Additionally, it is well known that the electro-optic characteristics of LCDs, such as transmittance and threshold voltage, also rely on the LCD switching modes. The temperature dependence of the electro-optic characteristics of the wide-viewing-angle LCD modes, such as in-plane switching (IPS), multidomain vertical alignment by patterned electrode (PVA), and fringe-field switching (FFS), have been studied, and the results showed that the FFS mode has lower temperature dependence compared to the IPS and PVA modes. Since the liquid crystal (LC) reorients in different ways in each mode, this result is associated with the temperature dependence of LC’s bend and twist elastic constants, and also with the position of the main reorientation, either in the middle or on the surface of the LC layer.
Sureshkumar, Palanivelu,Srivastava, Anoop Kumar,Jeong, Seok Jin,Kim, Miyoung,Jo, Eun Mi,Lee, Seung Hee,Lee, Young Hee American Scientific Publishers 2009 Journal of Nanoscience and Nanotechnology Vol.9 No.8
<P>An anomalous electrokinetic dispersion after contraction of carbon nanotube (CNT) cluster suspended in a vertically aligned nematic liquid crystal (LC) cell is demonstrated. CNT aggregates were firstly aligned toward the field line by dielectrophoretic (DEP) torque and secondly they were elongated above a certain threshold field due to interaction between the induced dipole moment of CNTs and external ac electric field. Below a certain breakdown field, the original morphology of the CNT aggregates was restored after the removal of the field where the elongation was fully reversible. Above breakdown electric field, CNT aggregates were ruptured and fragmented into small pieces and consequently CNTs were well dispersed in LC medium.</P>
Dang Phuc Toan,Srivastava Anoop Kumar,E-Joon Choi,Lee Ji-Hoon 한국물리학회 2021 Current Applied Physics Vol.23 No.-
We investigated dielectric properties of a hockey-stick-shaped liquid crystal (HLC). Two dielectric relaxation modes were observed at 0.91 kHz and 4.51 MHz. The low frequency relaxation modes in isotropic, smectic, and nematic phases are related to the motion of ions, collective tilt fluctuation, and rotation around the long molecular axis, respectively. Meanwhile, the high frequency relaxation modes in nematic and smectic phases was due to the rotation around the short axis of the molecules and hindered by the resistance of the ITO layers. We also examined the electrooptical response of the 5.0 wt% HLC-doped commercial nematic liquid crystal (LC) mixtures. The birefringence of the LC mixture was slightly increased, while the falling time and the rotational viscosity was decreased in the nematic phase.
Carbon Nanotube Effects on Electro-Optic Characteristics of Twisted Nematic Liquid Crystal Cells
Jo, Eun Mi,Srivastava, Anoop Kumar,Bae, Jung Jun,Kim, Miyoung,Lee, Myong-Hoon,Lee, Hee Kyu,Lee, Seung-Eun,Lee, Seung Hee,Lee, Young Hee Informa UK (TaylorFrancis) 2009 Molecular Crystals and Liquid Crystals Vol.498 No.1
이승희,하경수,채민아,Anoop Kumar Srivastava,이승은,정준호,Seung-Eun Lee 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.56 No.2
The light efficiency of the homogeneously aligned liquid crystal (LC) mode driven by fringe electric fields depends on the magnitude of the dielectric anisotropy when using a LC with positive dielectric anisotropy. However, this dependency is not observed when using a LC with negative dielectric anisotropy. This difference is mainly associated with the molecular reorientation especially in the tilt angle of the LC between the edges and the centers of the pixel electrodes in the voltage-on state. This paper explores the dependence of the light efficiency of the device on the magnitude of the dielectric anisotropy of the LC for both types of the LCs as functions of other cell parameters such as the rubbing angle and the cell gap.
Jeon, Eun-Jeong,Srivastava, Anoop Kumar,Kim, Mi-Young,Jeong, Kwang-Un,Choi, Jeong-Min,Lee, Gi-Dong,Lee, Seung-Hee The Korean Infomation Display Society 2009 Journal of information display Vol.10 No.4
As the physical properties of nematic liquid crystals vary with respect to temperature, the performances of liquid crystal displays (LCDs) are highly dependent on temperature. Additionally, it is well known that the electro-optic characteristics of LCDs, such as transmittance and threshold voltage, also rely on the LCD switching modes. The temperature dependence of the electro-optic characteristics of the wide-viewing-angle LCD modes, such as in-plane switching (IPS), multidomain vertical alignment by patterned electrode (PVA), and fringe-field switching (FFS), have been studied, and the results showed that the FFS mode has lower temperature dependence compared to the IPS and PVA modes. Since the liquid crystal (LC) reorients in different ways in each mode, this result is associated with the temperature dependence of LC's bend and twist elastic constants, and also with the position of the main reorientation, either in the middle or on the surface of the LC layer.