- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
State transition at electrohydrodynamic convection of twisted nematic liquid crystals
摘要： We study electrohydrodynamic convection (EHC) patterns in twisted nematic liquid crystal (TNCL) cells with an initial homeotropic alignment. In addition, we demonstrate switching characteristics due to the transition between the 90° and ?90? twisted states. The pattern formations are similar to those obtained in a parallel-aligned nontwisted liquid crystal cell. Calculations of the free energy in an initially, homeotropically aligned TNLC in an electric ?eld demonstrate that the energy barrier between the two states decreases with the increase of the electric ?eld. The mutual transition is caused by the ?uctuating ?ow at the dynamic scattering mode 2, where the energy barrier between the two states is reduced by applying a strong electric ?eld. These properties may be employed for the development of a redirectable dynamic lenticular lens, as an extended version of the dynamic lenticular lens using EHC. The transition between the two states caused by EHC is reversible, and the convection roll pattern of the Williams domain rotates by 90° at each transition.
关键词： state transition,homeotropic alignment,electrohydrodynamic convection,dynamic lenticular lens,twisted nematic liquid crystal
更新于2025-09-10 09:29:36
-
Vertically-aligned lead-free BCTZY nanofibers with enhanced electrical properties for flexible piezoelectric nanogenerators
摘要： Flexible lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3-0.2 mol%Y nano?bers (BCTZY NFs) were synthesized by electrospinning and their corresponding nanogenerators (NGs) with vertical alignments were fabricated. The low-temperature sintering properties of BCTZY NFs were investigated, to optimize their synthesis path and minimize the thermal energy consumption during the sintering process. The continuity, ?exibility, and stability of the BCTZ-based NFs were improved by adding Y3+. Moreover, the temperature-evolved Raman spectra displayed a high Curie temperature of 280 °C for BCTZY NFs, which was far higher than that of about 90 °C for BCTZ-based ceramic bulks, owing to the discontinuous physical property of NFs. The dielectric, ferroelectric, and piezoelectric properties of the vertically aligned BCTZY NFs/PDMS were estimated and compared with those of BCTZ NFs/PDMS composites, to verify the advantages of vertical alignments and the donor doping e?ect of Y3+. Vertically aligned BCTZY NF-based NGs showed an average VOC of 3.0 V and ISC of 85 nA by ?nger tapping, suggesting their potential applications in tiny energy harvesting.
关键词： Electrospinning,Lead-free BCTZY nano?bers,Vertical alignment,Piezoelectric nanogenerators
更新于2025-09-10 09:29:36
-
Band alignment of atomic layer deposited SiO <sub/>2</sub> on (010) (Al <sub/>0.14</sub> Ga <sub/>0.86</sub> ) <sub/>2</sub> O <sub/>3</sub>
摘要： The (AlxGa1?x)2O3/Ga2O3 system is attracting attention for heterostructure ?eld effect transistors. An important device design parameter is the choice of gate dielectric on the (AlxGa1?x)2O3 and its band alignment at the heterointerface. The valence band offset at the SiO2/(Al0.14Ga0.86)2O3 heterointerface was measured using x-ray photoelectron spectroscopy. The SiO2 was deposited by atomic layer deposition (ALD) onto single-crystal β-(Al0.14Ga0.86)2O3 grown by molecular beam epitaxy. The bandgap of the SiO2 was determined by re?ection electron energy loss spectroscopy as 8.7 eV, while high resolution XPS data of the O 1s peak and onset of elastic losses were used to establish the (Al0.14Ga0.86)2O3 bandgap as 5.0 eV. The valence band offset was determined to be 1.60 ± 0.40 eV (straddling gap, type I alignment) for ALD SiO2 on β-(Al0.14Ga0.86)2O3. The conduction band offset was 2.1 ± 0.08 eV, providing for a strong electron transport restriction.
关键词： x-ray photoelectron spectroscopy,(Al0.14Ga0.86)2O3,SiO2,atomic layer deposition,conduction band offset,band alignment,valence band offset
更新于2025-09-10 09:29:36
-
Roll-to-Roll (R2R) Production of Ultrasensitive, Flexible, and Transparent Pressure Sensors Based on Vertically Aligned Lead Zirconate Titanate and Graphene Nanoplatelets
摘要： Despite extensive advances in the use of piezoelectric materials in flexible electronics, they have numerous shortcomings, including low efficiency, limited flexibility, and lack of transparency. Additionally, the production of these materials is often limited to small batch processes which are difficult to scale up for mass production. A novel method to produce ultrasensitive, high performance, flexible, and transparent piezoelectric materials where both lead zirconate titanate nanoparticles, and graphene nanoplatelets are aligned together in polydimethylsiloxane under an AC electric field in the thickness (“Z”) direction, is reported here for the first time. The electric field alignment improves the piezoelectric response along with transparency and also reduces the amount of filler required to achieve outstanding piezoelectric properties. The resulting ultrasensitive piezoelectric film is able to sense the pressure of a bird feather (1.4 mg) dropped from a certain distance, whereas at the touch of a fingertip, it can generate up to 8.2 V signal. Moreover, the mass production compatibility of the system is also demonstrated by producing a 3 m long and 15 cm wide large-area sample via a novel 44′ long roll-to-roll manufacturing line which is designed and developed by the group.
关键词： piezoelectric pressure sensor,flexible and transparent sensors,electric field–induced alignment,roll-to-roll manufacturing,PZT and graphene nanoplatelets
更新于2025-09-10 09:29:36
-
39.1: <i>Invited Paper:</i> Novel Photo-Alignment Material for Ultra-High Definition VA LCDs
摘要： Ultra-high definition vertically photo-aligned LC-displays inherently suffer from lower backlight transmittance. We proved, experimentally and by simulation, that the transmittance is increased by lowering the pre-tilt angle. Novel material based on Rolic’s proprietary photo-alignment technology yielding low pre- tilt angles and high reliability is developed and qualified for mass production by CEC Panda.
关键词： Pre-tilt,Photo-alignment,LCMO,LCD,Transmittance
更新于2025-09-10 09:29:36
-
39.4: <i>Invited Paper:</i> Self-alignment of liquid crystal for multi-domain liquid-crystal display
摘要： By introducing photopolymerizable amphiphile organic monomers(PAOM) into nematic liquid crystals (NLC) with controlled amount of UV-curable reactive mesogen (RM), a multi-domain vertical-alignment LC device was successfully demonstrated. The device, possessing a vertically aligned LC director in four different azimuthal directions, exhibited a fast response time, wide-viewing-angle characteristics and high voltage holding ratio(VHR), in the absence of conventional polyimides vertical-alignment layers. The formation of automatic and robust vertical alignment layer was analyzed by using scanning electron microscopy(SEM).
关键词： Amphiphile organic monomers,vertical-alignment layers
更新于2025-09-10 09:29:36
-
[IEEE 2018 25th IEEE International Conference on Image Processing (ICIP) - Athens, Greece (2018.10.7-2018.10.10)] 2018 25th IEEE International Conference on Image Processing (ICIP) - Face Alignment by Combining Residual Features in Cascaded Hourglass Network
摘要： Fully Convolutional Networks (FCN) are popular in face alignment thanks to its capacity to retain accurate spatial information. In this work we study the effect of kernel functions of FCN for face alignment. We claim that neither the cross entropy nor the pixel-wise L2 losses can reflect the alignment error accurately if we generate the ground truth probability matrix with kernel functions. Based on this analysis, firstly, we develop a Cascaded Hourglass Network (CHN) as our baseline, and then regress the residual face shape via features obtained from the middle layer of the network, which are called Residual Features (RF). The proposed RF-CHN method obtains Normalized Mean Error (NME) of 6.84, which gives an error reduction of 0.21 compared to the current state-of-the-art on the challenging 300-W database.
关键词： Residual Features,Fully Convolutional Network,Face Alignment
更新于2025-09-10 09:29:36
-
Nano pattern transfer on acrylic polymers with UV irradiation for liquid crystal alignment
摘要： Ultra-violet nanoimprint lithography was utilized to transfer a one-dimensional nano pattern onto a hydrophilic ultra-violet cured polymer surface for use in liquid crystal displays. A master mold with the one-dimensional nano pattern was initially constructed using laser interference lithography, which is a fast and maskless process that can be employed over a large area. The UV cured polymer showed a hydrophilic characteristic, and was used as a homogeneous alignment layer. The nano-patterned ultra-violet polymer successfully aligned the liquid crystal molecules without defects. Additionally, the liquid crystal cell was characterized by high thermal stability due to the high thermal endurance of UV cured polymer. Therefore, the proposed ultra-violet nanoimprint lithography technique is beneficial for advanced liquid crystal devices with high brightness and resolution with numerous switching components that require a high thermal cost.
关键词： liquid crystal alignment,hydrophilic UV-cured polymer,thermal stability,Ultra-violet nanoimprint lithography
更新于2025-09-10 09:29:36
-
Formation of uniaxial strained Ge via control of dislocation alignment in Si/Ge heterostructures
摘要： Uniaxially strained Ge/SiGe heterostructures are fabricated by selective ion implantation technique, where dislocation alignments are highly controlled by the local defect introduction. Firstly, ion-implantation-defects are selectively induced into a Ge substrate, followed by the growth of a SiGe buffer layer. As a result, the SiGe on the implanted region is largely strain-relaxed due to the defects acting as dislocation sources. In contrast, it is demonstrated that anisotropic strain relaxation takes place in the SiGe on the unimplanted region, leading to the uniaxial strained SiGe. A strained Ge layer is pseudomorphically grown on the SiGe buffer and the same strain states are observed for the Ge layer. It is found that mis?t dislocations generated at the interface between the SiGe layer and the Ge substrate are aligned along only one direction. These one-directional dislocations are an origin of the uniaxial strain relaxation. Moreover, effects of ion-implantation stripe-pattern widths on the strain states are investigated. With the implanted line width increasing, the anisotropy of the strain in the unimplanted region is enhanced. From these results, it can be said that this technique opens a route to engineer dislocation alignments and anisotropic strain in semiconductor hetero structures toward high performance novel devices.
关键词： dislocation alignment,uniaxial strained Ge,Si/Ge heterostructures,selective ion implantation,anisotropic strain relaxation
更新于2025-09-10 09:29:36
-
Tuning the band alignment of p-type graphene-AsSb Schottky contact by electric field
摘要： By combining the electronic structures of graphene and monolayer AsSb via van der Waals force interaction, the intrinsic p-type Schottky contact can be obtained. Here, a series of theoretic calculations are performed to survey the effects of interlayer coupling and the band realignment of graphene-AsSb heterointerface. It reveals that intrinsic p-type Schottky barriers of 0.184 and 0.381 eV are formed for the two types of configurations. Besides, the intrinsic electronic properties of graphene and AsSb are roughly preserved. When the external electric field is applied, the Schottky barrier can be effectively tuned up by changing the external electric field intensity and further convert the p-type contact into the n-type contact. A variation of the Schottky barriers indicates a partial Fermi level pinning at the interfaces of AsSb. It results from the low density of interfacial states between graphene and AsSb. The barrier height of AsSb and the corresponding contact type can be flexibly tuned, which is of great importance in the design of novel transistors based two-dimensional materials and they provide meaningful guidelines.
关键词： AsSb,electric field,graphene,band alignment,Schottky contact
更新于2025-09-09 09:28:46