Development of triode type RF plasma enhanced CVD equipment for low temperature growth of carbon nanotube

Triode-type radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) equipment has been developed in order to grow well-aligned carbon nanotubes on Si and glass substrates at 550 °C. The CVD equipment employs a grid electrode in addition to the cathode and anode electrodes. The grid electrode allows the growth of a well-aligned carbon nanotube with an inside and an outside diameter of 7 and 17 nm, respectively. Moreover, the patterning growth of the well-aligned CNT on a glass substrate was also demonstrated.     

Extraction and purification of Polyhydroxyalkanoates (PHAs): application of Thermoseparating aqueous two-phase extraction

Being biodegradable, non-toxic and renewable as well as having similar or better properties than commercial plastics, polyhydroxyalkanoates (PHAs) can be a potential game changer in the polymer industry. Although viewed as a sustainable alternative to petrochemicals due to its biodegradability, PHAs are plagued with low commercial value due to their high production and recovery costs. Having the benefits of providing a mild environment for bioseparation, being environment-friendly and scalable, together with it its distinctive thermoseparating properties and ease of recyclability, thermoseparating-based aqueous two-phase extraction (ATPE) has provided the eco-friendly and economical solution to the PHA dilemma. ATPE-influencing factors such as types of thermoseparating polymer, concentration of phase-forming components, pH, and effect of centrifugation were investigated. Under the condition of 14 wt/wt% of EOPO 3900 concentration, 14 wt/wt% of ammonium sulfate concentration and pH 6 without the needs for extra centrifugation steps, a recovery yield and a purification factor of up to 72.2% and 1.61 fold can be achieved with the copolymers which can be recycled and reused twice. Thermoseparating ATPE has thus been proven to be a powerful primary purification tool for PHAs.     

Determination of Oxidation of Methyl Ricinoleates

Ricinoleate esters have desirable properties as biolubricants, but their oxidative stability has been questioned. To systematically study the stability of ricinoleate ester and its derivative, methyl esters of castor oil were prepared and methyl ricinoleate was isolated by solvent partitioning. Methyl 12‐acetyl ricinoleate was synthesized from the methyl ricinoleate by interesterification with excess methyl acetate and was then purified by solvent partitioning. The rates of oxidation of methyl linoleate, methyl oleate and the two ricinoleate esters were measured by oxidation of lipid dispersed on glass beads under three temperatures (40–80 °C). The relative amounts of the unoxidized methyl esters were determined periodically by gas chromatography, and the peroxide value of the oils was also determined. The oxidation rates were determined as the peroxide value increase rate, as well as the ester disappearance rate, and the stability of the various esters was compared. Overall, methyl ricinoleate was much more oxidatively stable than methyl oleate at mildly elevated temperatures, and the acetylation of the hydroxyl group on the 12th carbon decreased the stability.     

知“竹”常乐——2010台北花博“台湾园”设计

“台湾园”位于2010年台北国际花卉博览会寰宇庭园区,是当代的台湾风景园林师第一次有机会以台湾为主题思考,来诠释具台湾精神的庭园.整体设计融入台湾人民热情好客的处世精神与敬天畏地的生活态度,并目同时以“现代样貌”的景观表情,展示都市生活美学对于“人文”及“生态”议题的思考.作品完成后得到景观设计专业与一般民众的一致认可...     

Auto-flocculation through cultivation of Chlorella vulgaris in seafood wastewater discharge: Influence of culture conditions on microalgae growth and nutrient removal

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Decrease in equivalent series resistance of electric double-layer capacitor by addition of carbon nanotube into the activated carbon electrode

An electric double layer capacitor (EDLC) was fabricated with the addition of carbon nanotubes (CNTs) to the polarizable electrodes to act as a conducting material. This EDLC showed a low equivalent series resistance of 2.5 Ω. This value was lower than that of an EDLC fabricated with the addition of acetylene black, which is widely used in commercial EDLCs.     

Dynamic response of an elastic fence under wind action

Abstract

The along‐wind response of a surface‐mounted elastic fence under the action of wind was investigated numerically. In the computations, two sets of equations, one for the simulation of the unsteady turbulent flow and the other for the calculation of the dynamic motion of the fence, were solved alternatively. The resulting time‐series tip response of the fence as well as the flow fields were analyzed to examine the dynamic behaviors of the two.

Results show that the flow is unsteady and is dominated by two frequencies: one relates to the shear layer vortices and the other one is subject to vortex shedding. The resulting unsteady wind load causes the fence to vibrate. The tip deflection of the fence is periodic and is symmetric to an equilibrium position, corresponding to the average load. Although the along‐wind aerodynamic effect is not significant, the fluctuating quantities of the tip deflection, velocity and acceleration are enhanced as the fundamental frequency of the fence is near the vortex or shedding frequency of the flow due to the occurrence of resonance. In addition, when the fence is rather soft, a higher mode response can be excited, leading to significant increases in the variations of the tip velocity and acceleration.     

Hysteresis in Conjugated Polymer Thin Film Transistors Generated by Chain Relaxation

The hysteresis phenomenon in a polymer thin film transistor (PTFT) with either poly(3‐hexylthiophene), poly(3‐dodecylthiophene), or poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylene vinylene] is investigated over a wide range of temperatures, and found to be generated by the delay in main chain ring distortion with an applied electric field. In the temperature range for side chain relaxation, main chain motion induced by side chain motion already starts such that polarization of the main chain by the applied electric field is permitted but in a limited extent and is not in phase with the variation in electric field. In the main chain relaxation temperature range, the extent of segmental motion increases, which leads to the main chain being more realignable by the applied electric field and thus a reduced hysteresis. After main chain relaxation is complete, the ring can distort more freely and chain segments are able to realign in phase with the applied electric field, which leads to a leveling off of the hysteresis. This investigation shows for first time that the chain relaxation in conjugated polymers is the origin of the hysteresis in PTFT devices.