다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Fujishima and Honda (1972) demonstrated the potential of titanium dioxide (TiO2) semiconductor materials to split water into hydrogen and oxygen in a photo-electrochemical cell. Their work triggered the development of semiconductor photocatalysis for a wide range of environmental and energy applications. One of the most significant scientific and commercial advances to date has been the development of visible light active (VLA) TiO2 photocatalytic materials. In this review, a background on TiO2 structure, properties and electronic properties in photocatalysis is presented. The development of different strategies to modify TiO2 for the utilization of visible light, including non metal and/or metal doping, dye sensitization and coupling semiconductors are discussed. Emphasis is given to the origin of visible light absorption and the reactive oxygen species generated, deduced by physicochemical and photoelectrochemical methods. Various applications of VLA TiO2, in terms of environmental remediation and in particular water treatment, disinfection and air purification, are illustrated. Comprehensive studies on the photocatalytic degradation of contaminants of emerging concern, including endocrine disrupting compounds, pharmaceuticals, pesticides, cyanotoxins and volatile organic compounds, with VLA TiO2 are discussed and compared to conventional UV-activated TiO2 nanomaterials. Recent advances in bacterial disinfection using VLA TiO2 are also reviewed. Issues concerning test protocols for real visible light activity and photocatalytic efficiencies with different light sources have been highlighted.

/pdf/a-review-on-the-visible-light-active-titanium-dioxide-2qg81s4yao.pdf

A review on the visible light active titanium dioxide photocatalysts for environmental applications

The science and technology of ultracapacitors are reviewed for a number of electrode materials, including carbon, mixed metal oxides, and conducting polymers. More work has been done using microporous carbons than with the other materials and most of the commercially available devices use carbon electrodes and an organic electrolytes. The energy density of these devices is 3¯5 Wh/kg with a power density of 300¯500 W/kg for high efficiency (90¯95%) charge/discharges. Projections of future developments using carbon indicate that energy densities of 10 Wh/kg or higher are likely with power densities of 1¯2 kW/kg. A key problem in the fabrication of these advanced devices is the bonding of the thin electrodes to a current collector such the contact resistance is less than 0.1 cm2. Special attention is given in the paper to comparing the power density characteristics of ultracapacitors and batteries. The comparisons should be made at the same charge/discharge efficiency.

Ultracapacitors: Why, How, and Where is the Technology

This review paper encompasses a detailed study of semiconductor metal oxide (SMO) gas sensors. It provides for a detailed comparison of SMO gas sensors with other gas sensors, especially for ammonia gas sensing. Different parameters which affect the performance (sensitivity, selectivity and stability) of SMO gas sensors are discussed here under. This paper also gives an insight about the dopant or impurity induced variations in the SMO materials used for gas sensing. It is concluded that dopants enhance the properties of SMOs for gas sensing applications by changing their microstructure and morphology, activation energy, electronic structure or band gap of the metal oxides. In some cases, dopants create defects in SMOs by generating oxygen vacancy or by forming solid solutions. These defects enhance the gas sensing properties. Different nanostructures (nanowires, nanotubes, heterojunctions), other than nanopowders have also been studied in this review. At the end, examples of SMOs are given to illustrate the potential use of different SMO materials for gas sensing.

Semiconductor metal oxide gas sensors: A review

In this work, electrospun polyaniline (PANI) micro/nano dots on quartz crystal microbalance (QCM) sensor were used to sense the humidity at room temperature. A QCM humidity sensor is made by coating a low-cost commercial quartz crystal resonator with Polyaniline (PANI), which is one of the most promising polymers for sensing applications due to its relatively high stability. The electrospinning technique is used to coat the PANI nanometer-scale thin film to the electrode of quartz crystal. From experimental results, it was found that PANI coating on the QCM electrode is an effective way to improve humidity-sensing characteristic of QCM sensor. The PANI coated sensor has good response to the humidity with short response and recovery times. The experimental results show that the humidity sensitivity of PANI coated QCM sensor considerably depends on the thickness of PANI layer coated on the sensor electrode.

Quartz Crystal Microbalance humidity sensor using electrospun PANI micro/nano dots

In this work, a new humidity sensor is developed by employing piezoresistive microcantilever with inkjet printed PEDOT/PSS sensing layers. 200 µm long, 50 µm wide and 3.75 µm thick microcantilever is designed and fabricated by PolyMUMP, which is a commercial Multi-User MEMS Process. The polysilicon piezoresistive layer in the microcantilever acts as a transduction component that will change its resistance when there is bending of microcantilever due adsorbed water molecules on PEDOT/PSS sensing layers. PEDOT/PSS layers are directly patterned on microcantilever by a commercial Dimatrix material inkjet printer. The resistances of microcantilever sensors are monitored as a function of humidity, which is simultaneously measured by a commercial humidity sensor. The resistance value is found to decrease with the humidity and the calibration curve of resistance change is linearly proportional to the percent of relative humidity in range from 20.3–66.3 %RH with high sensitivity. The results show that the piezoresistive microcantilever sensor with inkjet printed PEDOT/PSS sensing layers is a promising candidate for humidity sensing.

Humidity sensor based on piezoresistive microcantilever with inkjet printed PEDOT/PSS sensing layers

This work presents a new method for mass fabrication of a new microfluidic device with integrated graphene-based electrochemical electrodes by the screen printing technique for in-channel amperometric detection Graphene-based working and counter electrodes were fabricated by screen printing graphene paste on a glass substrate, followed by screen printing of a silver/silver chloride (Ag/AgCl) reference electrode The screen-printed substrate was then bonded to a prefabricated polydimethylsiloxane (PDMS) sheet containing microchannels via oxygen plasma treatment The developed microfluidic device was then applied for glutathione analysis in pharmaceutical products The method offers effective and fast glutathione detection with good analytical features including a wide dynamic range (10–500 μM) and a low detection limit (3 μM) In addition, the screen printed graphene electrode (SPGE) exhibits a good stability in a microfluidic flow system and good repeatability for amperometric detection The method has numerous advantages including low fabrication cost, high sensitivity, high throughput and satisfactory reproducibility Thus, it holds great promise for advanced analytical applications

Screen-printed graphene-based electrochemical sensors for a microfluidic device

In this work, the fabrication and performance of flexible alternating current electroluminescent (AC-EL) devices for ammonia (NH3) detection at room temperature are presented for the first time. The AC-EL gas sensor was fabricated by the screen-printing of a ZnS:Cu,Cl phosphor and PEDOT:PSS sensing layers. The effects of parameters including applied voltage, excitation frequency and waveform on light emission and luminance intensity of the AC-EL gas sensor were systematically investigated. From gas-sensing characterization, the AC-EL gas sensor exhibited very high selectivity and a linear response to NH3 in the concentration range of 100–1000 ppm at room temperature. A sensing mechanism of the EL gas sensor was proposed based on the resistance change of the PEDOT:PSS sensing layer via a charge-transfer process.

/pdf/flexible-alternating-current-electroluminescent-ammonia-gas-4asik1t5j5.pdf

Flexible alternating current electroluminescent ammonia gas sensor

Lenslet integrated Micro-Electro-Mechanical Deformable Micromirrors (LMEM-DMs) are electrostatic micromirror arrays fabricated through a commercial surface micromachining process and integrated with polymer or glass microlenses. The electronics resins (Photo-BCB) which are photo-sensitive polymers were used to fabricate polymer microlens arrays. A 4 X 4 element photo-BCB Cyclotene microlens array was fabricated on a thin quartz substrate. Self-aligned soldering flip-chip assembly is applied to integrate microlens arrays directly over the micromirrors. The lens/mirror gap is controlled using the final height of solder balls, and the lateral alignment is achieved by the solder self-aligning mechanism. The LMEM-DM is attractive due to its low cost and the low drive voltages. The use of a lenslet to focus the incoming laser beam onto the reflective surface of a micromirror substantially increases overall optical fill factor of the micromirror array. The LMEM-DM provides superior aberration correction with low residual diffraction effects. For mirror deflections much smaller than the lenslet focal length, the LMEM-DM behaves as a phase-only modulating optical element. The LMEM-DM thus serves as a rugged, compact optical element for beam steering, beam shaping, and aberration correction applications.

Adisorn Tuantranont

Papers

Quartz Crystal Microbalance humidity sensor using electrospun PANI micro/nano dots

Humidity sensor based on piezoresistive microcantilever with inkjet printed PEDOT/PSS sensing layers

Screen-printed graphene-based electrochemical sensors for a microfluidic device

Flexible alternating current electroluminescent ammonia gas sensor

Self-aligned assembly of microlens arrays with micromirrors