
Shug-June HwangNational United University · electro-optical engineering
Shug-June Hwang
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187
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Publications (187)
This study investigates the quantitative photomechanical actuation properties of bifunctional acrylate liquid crystal (LC242) doped with azo dye and graphene oxide (GO) nanocomposites under a 40 mW/cm² green laser. A photo-responsive liquid crystal polymer (LCP) was developed via UV curing, utilizing methyl red (MR) for its photoisomerism and GO fo...
Modern research has long focused on controlling and optimizing the dielectric, electro-optical and optical attributes of liquid crystals (LCs) to increase their technological value. Numerous approaches have been investigated for this reason in an effort to overcome various issues such as high response time, high driving voltage requirements, low di...
Paper-based microfluidic sensors for point-of-care applications represent an exceptional strategy for facilitating rapid sensing within clinical settings. Despite their considerable promise, the ongoing research objective lies in efficiently printing hydrophobic microfluidic channels (μPADs) onto hydrophilic paper while minimizing
expenditure. This...
Encapsulation of the cholesteric liquid crystal (CLC) into the core of poly(vinylpyrrolidone) (PVP) microfibers is accomplished via coaxial electrospinning technology and is applied to detect volatile organic compounds (VOCs). The impacts of various process parameters on the morphology of CLC fibers are deeply explored. The periodic arrangement of...
In this study, an optical sensor is developed, incorporating hydrogen-bonded photonic array dots containing poly(acrylic acid) (PAA) within a polymer cholesteric liquid crystal interpenetrating polymer network (PCLCIPN) framework, thereby effectively...
This study examines the influence of SnSe nanospheres (NSs) on the dielectric and electro-optical properties of liquid crystal (LC) blends. A notable Debye relaxation phenomenon has been observed within a few Hz to near kHz frequency regime. This phenomenon is ascribed to the accumulation of mobile charge carriers near the cell electrodes (electrod...
A new, to the best of our knowledge, in-fiber Mach–Zehnder interferometric sensor is proposed and experimentally demonstrated for detecting Cu²⁺ ions in an aqueous environment. The sensor is fabricated simply and cost-effectively by arc-fusing a short section of hollow optical fiber between two standard single-mode fibers and is functionalized by d...
A responsive hydrogen-bonded cholesteric liquid crystal polymer (CLCP) film with controlled porosity was fabricated as an optical sensor to distinguish between methanol and ethanol in alcohol solutions. To facilitate responding the alcohols, porosity was generated by removing the nonreactive liquid crystal agent, and the hydrogen bridges of CLCP we...
The liquid crystal (LC)-based sensor has received growing interest in recent years, due to the real-time detection of chemical reaction based on the stimuli-induced reorientation of LC molecules. In this work, a LC-based sensor for label-free identification of hydrogen peroxide (H2O2) solution is demonstrated. The biosensor is achieved mainly by us...
A relatively simple and cost-effective method to realise a novel long-period fibre grating (LPFG) based on blue phase liquid crystal (BPLC) composites was proposed and experimentally demonstrated by implementing photopolymerisation-induced phase separation (PIPS) through a binary photomask. The BPLC-polymer composite zones were obtained by a proces...
A simple, low-cost, and quickly reversible sensor based on polymer cholesteric liquid crystal film (PCLCF) for detecting organic vapour is proposed in this work. PCLCF exhibits an obvious red shift of the reflective colour in the early stages of acetone vapour diffusion and has the ability to quickly recover as vapour is released. The red shift in...
We demonstrated a relatively simple and effective method to fabricate a periodically isolated polymer wall of blue-phase liquid crystal Fresnel lens (BPLCFL) by employing a single-masking process of the ultraviolet (UV) irradiation, leading to excellent photopolymerisation-induced phase separation between blue -phase liquid crystal (BPLC) molecules...
A simple method for fabricating polarisation-independent blue-phase liquid crystal phase grating is demonstrated by implementing photopolymerisation-induced phase separation through a binary photomask. The dynamic focusing property of the proposed liquid crystal grating is independent of the polarisation state of incident light. The efficiency of v...
A simple method for fabricating a polarisation independent blue-phase liquid crystal Fresnel lens (BPLCFL) is demonstrated by utilising the photo-polymerisation-induced phase separation. The BPLC/polymer binary Fresnel zones is obtained well by periodic UV illumination with phase separation of the BPLC molecules and UV-curable pre-polymer mixture....
All-fiber curvature sensors based on a liquid crystal-filled fiber Mach–Zehnder interferometer (LCF-MZI) are proposed and experimentally demonstrated for high performance measurements of very small curvatures from 0 to 0.0667 m⁻¹, which is usually hard to be precisely monitored by well-known methods. Such a curvature sensor can be easily fabricated...
In this work, we report an easily visualized liquid crystal (LC)-based structure to study the biological molecules interactions between Bovine serum albumin (BSA) and BSA antibody. The antibody concentration can be detected from 1ug to 10ng based on the proposed LC-based biosensor.
In this study, we propose a simple but very effective method that enables fabrication of all fiber liquid crystal interferometer as a high sensitive refractive index (RI) sensor. Experimental results show that the maximum RI sensitivity of the proposed sensor is 261.3 nm/RIU (refractive index unit).
We propose a novel and simple method for constructing a switchable polarization-independent Fresnel lens using blue phase liquid crystal (BPLC)/polymer composite films, the maximum diffraction efficiency reaches 36 % regardless of the polarization state of incident light, which approaches the theoretical limit ∼41 %.
We demonstrate a high sensitivity all-fiber Mach–Zehnder interferometer (MZI) based on radial-aligned liquid crystal (LC) in a hollow optical fiber (HOF). The transmission spectrum of the liquid crystal-filled fiber MZI (LCF-MZI) was measured at different temperatures, and the thermal-induced wavelength shift of the interference spectrum probed. Th...
A controllable multi-wavelength laser from a dye-doped cholesteric liquid crystal (DDCLC) cell is demonstrated by incorporating self-assembled polyhedral oligomeric silsesquioxane (POSS) nanoparticles (NPs). Multi-wavelength lasing emission is achieved by formation of multiple planar domains; this formation is dominantly influenced by the vertical...
We demonstrated a simple and cost-effective method to fabricate all fiber Mach–Zehnder interferometer (MZI) based on cascading a short section of liquid crystal (LC)-filled hollow-optic fiber (HOF) between two single mode fibers by using automatically splicing technique. The transmission spectra of the proposed MZI with different LC-infiltrated len...
The nanoparticle-induced vertical alignment (NIVA) of the nematic liquid crystals (LC) is applied to achieve an adaptive flat LC microlens with hybrid-aligned nematic (HAN) mode by dropping polyhedral oligomeric silsesquioxane (POSS) nanoparticle solution on a homogeneous alignment layer. The vertical alignment induced by the POSS nanoparticles res...
An electrically controllable liquid crystal (LC) microlens with polymer crater, which is simply prepared by droplet evaporation, has been previously proposed as a focusing device possessing excellent characteristics in optical performance, especially for the capability of tunable focal lengths. As the alignment layer on the crater surface cannot be...
A simple and low-cost technique is proposed to construct a tunable liquid crystal (LC) microlens with a crater polymer structure, which is prepared using micro-drop technology and 2-step UV polymerization. The dimensions and the geometric profile of the restructured polymer surface significantly depend on the volume of the micro droplet, and the UV...
In this work, the micro-drop technology was applied to fabricate tunable LC microlens, which was composed of LC and UV curable polymers. The formed mechanism was significantly dependent on the dropped liquid volume, UV dose, and precuring time. The crater morphology of the microlens can be controlled by changing these parameters. The focal length o...
The surface energy of a conventional homeotropic polyimide (PI) alignment layer was altered via ultraviolet (UV) light irradiation, and the pretilt angle of the PI was changed along with the surface energy. The surface energy can be controlled by either UV exposure time or irradiation intensity. A switchable liquid crystal Fresnel lens (LCFL) was c...
Taiwan has the highest prevalence and 4 th highest incidence of end-stage renal disease in the world. The cost of dialysis occupies heavy medical expenses of the National Health Insurance. Among many reasons contributing to this condition, the high prevalence and low awareness of chronic kidney disease (CKD) may be one of the most important factors...
A label-free detection of surfactants at interfaces between aqueous phases and liquid crystals (LC) is proposed. The micro-grating structure was applied to monitor the influence of different concentration of surfactants solution on the orientational response of the LC molecules.
A label-free detection of surfactants at interfaces between aqueous phases and liquid crystals (LC) is proposed. The micro-grating structure was applied to monitor the influence of different concentration of surfactants solution on the orientational response of the LC molecules.
A switchable liquid crystal (LC) Fresnel lens was demonstrated by the UV-modified alignment layer for producing an alternation of hybrid-aligned and vertically-aligned LC zones. A polarization-independent Fresnel lens can be obtained by circular rubbing, and a high diffraction efficiency of ∼23% is reached with a low driving voltage of 1.2 V.
We investigate the stability in the memory state of the silica nanoparticle doped hybrid aligned nematic (SN-HAN) cell. The mixed polyimide (PI)-coated planar substrate provides the SN-HAN cell with a stable memory state. The mixed PI comprises the homogeneous PI and small amounts of the homeotropic PI (H-PI). The tiny H-PI dopant decreases the sur...
We investigate the stability of the memory state of the silica-nanoparticle-doped hybrid aligned nematic (SN-HAN) cell. The memory stability of the cell is attributed to the employed planar substrate, which is coated with a homogeneous polyimide (H-PI) film. A H-PI film with a low H-PI solid concentration gives the cell high memory stability. This...
We investigate the stability of the memory state of the silica-nanoparticle-doped hybrid aligned nematic (SN-HAN) cell. The memory stability of the cell is attributed to the employed planar substrate, which is coated with a homogeneous polyimide (H-PI) film. A H-PI film with a low H-PI solid concentration gives the cell high memory stability. This...
A simple method to make a switchable liquid crystal (LC) Fresnel lens with high diffraction efficiency and a low driving voltage was proposed based on the photo-induced surface modification of the vertical alignment layer. UV illumination alters the pretilt angle of alignment layers, a Fresnel zone-distribution hybrid alignment in the homeotropic L...
A broadband cholesteric liquid crystal (CLC) device with a multi-domain structure is demonstrated by using an aggregation of polyhedral oligomeric silsesquioxane (POSS) nanoparticles in the CLC layer. The aggregation pattern of the self-assembled POSS nanoparticles depends on the concentration of POSS doped in the mixture of POSS/CLC and the coolin...
The pretilt angles of liquid crystal molecules can be controlled by using conventional polyimide (PI) alignment material doped with different concentrations of Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticles, which have been observed to spontaneously induce vertical alignment. The addition of POSS in the homogenous PI changes the surface...
The pretilt angles θp of liquid crystal molecules can be controlled by using conventional polyimide alignment (PI) material doped with different concentrations of Polyhedral Oligomeric Silsequioxanes (POSS) nanoparticle. The addition of POSS in the homogenous PI changes the surface energy of the PI and generates the variable θp. Experimental result...
A simple method to make a switchable liquid crystal Fresnel lens with high diffraction efficiency and a low driving voltage was proposed by photo-induced surface modification of vertical alignment layer. Remarkable diffraction efficiency close to the theoretical limit was detected and demonstrated to depend sensitively on the applied voltage.
In this paper, a novel method was proposed to fabricate a pure liquid crystal (LC) structure using the thermal annealing process, which successfully expel the residual monomers from the LC volume and considerably enhance optical properties of the polymer-wall LC devices. Using a series of experiments, the impact of annealing process on the purity o...
The nanoparticles-induced vertical alignment technique was applied to generate variable liquid-crystal pretilt angles based on doping different concentrations of polyhedral oligomeric silsesquioxane (POSS) nanoparticles in the planar-aligned liquid crystal cells. Competition between the homogeneously aligned polyimide layer and POSS-induced spontan...
The nanoparticles-induced vertical alignment (NIVA) of the nematic liquid crystals (LC) was proposed to make a tunable liquid-crystal flat microlens with hybrid-aligned nematic (HAN) mode, which was fabricated using micro drop technology. The minute amount of nanoparticle solution was dropped on the selective area, which was surrounded by homogeneo...
Polyhedral oligomeric silsesquioxane (POSS) nanoparticle has been applied on the indium tin oxide (ITO) glass substrate as the alignment layer of homeotropic liquid crystal devices (LCD). The characteristics of POSS nanoparticle alignment film fabricated by different methods, spin coating, melting, melting and rubbing, were systematically investiga...
We have found that nanoparticles of polyhedral oligomeric silsesquioxane (POSS) can induce vertical alignment in nematic liquid crystal (LC) cells as long as the doped weight percentage of POSS in the LC cells is higher than ~1%. Such nanoparticle-induced vertical alignment (NIVA) is a very suitable technique for application in the low-temperature...
The thermal annealing process was proposed to purify the pixel regions of a liquid crystal (LC) cell with polymer walls. This technique, based on thermal‐induced phase separation, successfully evicts the residual monomers from the LC volume and significantly improves electro‐optical properties of the polymer‐wall LC devices. The influence of the an...
Aromatic polyurea-based waveguides were fabricated by the evaporation and deposition of a diamino monomer and a diisocyanate monomer onto an indium tin oxide (ITO) glass substrate in a vacuum chamber. The nonlinear I–V behaviors of the polyurea film were characterized in situ during poling. Fourier transform infrared spectroscopy and the heterodyne...
Cyclic olefin copolymer (COC) substrate surface was modified by plasma treatment under oxygen atmosphere. The surface properties were evaluated by contact angle measurement, atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS). It was found that the surface acquired oxygen containing polar functional groups such as C–O, C=O, whi...
A total of 461 patients at the Veterans General Hospital, Taipei who had received blood transfusions since March 1981 were followed prospectively with serum biochemistry tests and viral hepatitis markers before and after the blood transfusions, periodically for at least 6 months. Sixty-three (13.7%) patients developed post-transfusion hepatitis (PT...
A phase‐sensitive measurement technique is proposed to characterise polymer wall formation in a nematic liquid crystal cell. The impact of photopolymerisable monomer concentration and curing time on the electro‐optical properties of polymer‐wall LC cells was studied. The experimental results indicate that optimum curing conditions for constructing...
A common-path heterodyne interferometer is proposed to determine the surface anchoring energy of a homogeneously aligned nematic liquid crystal (LC). This technique measures, with high sensitivity, the phase retardation of a nematic LC cell as a function of the applied voltage. According to the measured voltage-dependent phase retardation of the LC...
Cyclic olefin copolymer (COC) was used as flexible polymer substrate for the next-generation flat-panel displays (FPD). Surface roughness and optical properties of different thermally treated flexible polymer substrates were observed with an atomic force microscope (AFM) and a visible spectrometer, respectively. In addition, in this study, we found...
A novel flexible polymer was used for the new generation display panel, which was prepared by thermal annealing treatments. Atomic force microscope (AFM) and visible spectroscopy were employed to measure the surface roughness and the optical transparency of the substrates. Mechanical cycles bending were carried on the flexible substrates in this st...
We previously reported 2 hemodialysis (HD) patients with recurrent infections and selective immunoglobulin A deficiency (IgAD). We further demonstrated that serum IgA levels were lower and the prevalence of IgAD was higher in uremic patients. The exact mechanisms of IgAD in uremic patients largely remained unclear. In some patients, it was caused b...
— The high-sensitivity pretilt-angle measurement of liquid-crystal displays, based on the modified crystal-rotation configuration and the use of a common-path heterodyne interferometer, is proposed. In this technique, environmental disturbance and surface reflection are eliminated to a large extend, thus providing advantages for both constructing a...
Parathyroid cells synthesize and release endothelin-1 (ET-1). ET-1 displays an in vitro inhibitory effect on basal parathyroid hormone (PTH) secretion and also counteracts PTH hypersecretion stimulated by low calcium. Such effects are further demonstrated in vivo, independent of the changes in calcitonin. We propose that ET-1 may regulate the patho...
A powerful method for the phase retardation measurement of a reflective liquid crystal cell is presented. The proposed method is based on the heterodyne interferometer theory for probing cell parameters. Due to common-path optical arrangement, a fast measurement with high accuracy and sensitivity was possible. Both theoretical analysis and experime...
Indium tin oxide (ITO) thin films were deposited on cyclic olefin copolymer substrate at room temperature by an inverse target sputtering system. The crystal structure and the surface morphology of the deposited ITO films were examined by X-ray diffraction and atomic force microscopy, separately. The electrical properties of the conductive films we...
In this study, the surfaces of the multi-walled carbon nanotubes (MWNTs) were treated by acrylic acid. The acid-treated MWNTs were functionalized and were characterized by Infrared spectroscopy. The MWNTs were opened at their ends by ultrasonic treating and UV irradiating. Different adding amounts of the opened MWNTs were filled to the epoxy resin,...
A simple and novel optical heterodyne interferometer based on phase measurement was developed to measure liquid crystal cell parameters. Due to a common-path configuration utilized in this method, the Fabry-Perot effect and surface reflection could be eliminated in measurement, and a highly accurate measurement was expected. Based on the experiment...
New polymeric waveguide films were fabricated by electric field poling procedures and the electric and optical properties of the poled films were examined with polarized infrared spectroscopy and m-line spectroscopy. The lowering of the amide band intensity in the infrared spectra shows direct evidence of the poling treatments. The optimum poling t...
In this study, we developed a novel flexible organic light emitting diodes (OLEDs) substrate by simple annealing treatment on the cyclic olefin copolymer (COC). After proper thermal treatment the optical transparency of the flexible plastic substrate increased. This could evidently be observed by visible spectra. In addition, some of the infrared a...
A novel cyclo olefin copolymer (COC) waveguide film was fabricated and characterized. The optical properties as well as the absorption spectrum of this polymer film were observed using a prism coupler and by Fourier transformation infra-red (FTIR) spectroscopy. Atomic force microscopy (AFM) was also used to monitor the morphology of the waveguide f...
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and
Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early
dhildhood mortality and growth failure data and their association with maternal
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and
Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early
dhildhood mortality and growth failure data and their association with maternal
The electro-optic (E-O) properties of the slab polymer waveguide induced by electric poling have been studied experimentally. The thin film waveguide was prepared by a synthesized polymer polypelargonamide and poled by applying voltage between the electrodes. I–V curves and E-O characteristics of the polymer films were in-situ measured during polin...
The birefrigent performance of a poled polymer polyamide 7 (PA-7) guiding layer induced by dipole realignment was examined by the dichroic-Fourier transformation infrared spectroscopy (FTIR) method and with Attenuated total reflection (ATR) spectroscopy techniques. In this study an efficient discrete Fourier transform domain (DFT) technique was use...
The possible association between the risk of death from renal failure NO and the levels of calcium in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Characteristics for all eligible RF-related deaths (2469 cases) among Taiwan residents from 1991 through 2000 were compared with those of people who...