A multiwalled carbon nanotube (MWCNT) field emitter is developed as the electron source for a microcolumn-based field-emission scanning electron microscope (SEM). A MWCNT is first attached onto a tungsten (W) support tip using the nanomanipulator in the SEM. Then, an electrical bias is applied between the MWCNT field emitter and W tip to improve the contact between them, which lowers the threshold voltage for field emission. An emission current stability test showed that the emission current is stable. The fabricated MWCNT emitter exhibits a high emission current of 12 μA and sample current of around 2 nA, even at a low tip bias of 350 V in the microcolumn. The tip bias is much lower, and the sample current is higher than the equivalent values reported for W tips. The authors acquired images of a 1000-mesh copper grid using the microcolumn-based SEM with a MWCNT field emitter as the source. Our results suggest that MWCNTs should be considered a promising candidate as an electron source for microcolumns.

No abstract

We have optimized the operation conditions of the laser for the patterning in the FM/M/FM multi-layer, which can be readily used for the fabrication of the micro thin-film inductor. A diode-pumped Nd : YAG laser was actively Q-switched in order to obtain a high power short pulse laser beam whose spatial mode was TEM 00 mode. The measured pulse width was about 200 ns, its peak power was 25 kW, and the used pulse repetition rate was set to be 5 kHz. The optimal energy of a laser pulse was found to be 5 mJ and the focused beam with diameter of 5 -10 µm was launched to the FM/M/FM multi-layer. Due to the high intensity of the laser beam, the major interaction between laser beam and the material is vaporization rather than melting. The pattern formed by this vaporization process was very clear and had a line width as narrow as 20 µm.

Numerical design of outer diameter remote field eddy current probe for the inspection of nuclear fuel rod AIP Conf. Proc. 557, 953 (2001); 10.1063/1.1373859State-of-the-art and recent developments of high-power gyrotron oscillators AIP Conf.The design of a cathode to operate in an oxygen-rich environment AIP Conf.

Medical devices, which enhance the quality of life, have experienced a gradual increase in demand. Various research groups have attempted to incorporate soft materials such as skin into wearable devices. We developed a stretchable substrate with high elasticity by forming a porous structure on polydimethylsiloxane (PDMS). To optimize the porous structure, we propose a manufacturing process that utilizes a high-pressure steam with different viscosities (400, 800, 2100, and 3000 cP) of an uncured PDMS solution. The proposed method simplifies the manufacturing of porous structures and is cost-effective compared to other technologies. Porous structures of various viscosities were formed, and their electrical and mechanical properties evaluated. Porous PDMS (3000 cP) was formed in a sponge-like three-dimensional porous structure, compared to PDMS formed by other viscosities. The elongation of porous PDMS (3000 cP) was increased by up to 30%, and the relative resistance changed to less than 1000 times with the maximum strain test. The relative resistance increased the initial resistance (R0) by approximately 10 times during the 1500-times repeated cycling tests with 30% strain. As a result, patch-type wearable devices based on soft materials can provide an innovative platform that can connect with the human skin for robotics applications and for continuous health monitoring.

The demand on the electron beam (e-beam) for the inspection of semiconductor devices or display panel is rapidly increasing since e-beam cannot only monitor the small structures but also has the potential of detecting electrical troubles or repairing the defects. However, the merit of e-beam is limited because of the high cost, low throughput, and the possible damage due to the high e-beam energy. A microcolumn is a strong candidate to solve these limitations as its size is extremely miniaturized (both column diameter and height can be reduced down to a few millimeters) and the output e-beam energy is as low as 100–1000 eV. In this work, the authors tried to test the inspection of defects by applying a low voltage microcolumn to liquid crystal display panel. In order to demonstrate the authors’ inspection method, they extracted a 7’’ thin film transistor-liquid crystal display (TFT-LCD) panel from the production line just after completing the pixel structures and used this panel as a test sample. On the selected panel, the authors intentionally made some defects such as open data or gate lines by cutting some points using a laser beam. They operated their microcolumn with a beam energy of 300 eV and obtained the scanning images of the panel while operating the panel with specific operation conditions. The operation parameters for the test TFT-LCD panel such as the voltages applied to the gate lines, data lines, and storage capacitors was fixed at two specific sets of values. Then, the image obtained by the secondary electron reflects the information on the electrical state of the pixels as well as the geometrical ones. By combining the two sets of data, the authors could explain the correlation between the irregular behavior in the image contrast and the open defects and the detailed results will be discussed.

The aim of this study was to remove 5-hydroxymethyl furfural (5-HMF) and furfural, known as fermentation inhibitors, in acid pretreated hydrolysates (APH) obtained from Scenedesmus obliquus using activated carbon. Microwave-assisted pretreatment was used to produce APH containing glucose, xylose, and fermentation inhibitors (5-HMF, furfural). The response surface methodology was applied to optimize key detoxification variables such as temperature (16.5–58.5 °C), time (0.5–5.5 h), and solid–liquid (S-L) ratio of activated carbon (0.6–7.4 w/v%). Three variables showed significant effects on the removal of fermentation inhibitors. The optimum detoxification conditions with the maximum removal of fermentation inhibitors and the minimum loss of sugars (glucose and xylose) were as follows: temperature of 36.6 °C, extraction time of 3.86 h, and S-L ratio of 3.3 w/v%. Under these conditions, removal of 5-HMF, furfural, and sugars were 71.6, 83.1, and 2.44%, respectively, which agreed closely with the predicted values. When the APH and detoxified APH were used for ethanol fermentation by S. cerevisiae, the ethanol produced was 38.5% and 84.5% of the theoretical yields, respectively, which confirmed that detoxification using activated carbon was effective in removing fermentation inhibitors and increasing fermentation yield without significant removal of fermentable sugars.

No abstract