Evaporative characteristics of sessile nanofluid droplet on micro‐structured heated surface

Micro‐structure patterned substrates attract our attention due to the special and programmable wettabilities. The interaction between the liquid and micro/nano structures gives rise to controllable spreading and thus evaporation. For exploration of the application versatility, the introduction of nanoparticles in liquid droplet results in interaction among particles, liquid and microstructures. In addition, temperature of the substrates strongly affects the spreading of the contact line and the evaporative property. The evaporation of sessile droplets of nanofluids on a micro‐grooved solid surface is investigated in terms of liquid and surface properties. The patterned nickel surface used in the experiments is designed and fabricated with circular and rectangular shaped pillars whose size ratios between interval and pillars is fixed at 5. The behavior is firstly compared between nanofluid and pure liquid on substrates at room temperature. For pure water droplet, the drying time is relatively longer due to the receding of contact line which slows down the liquid evaporation. Higher concentrations of nanoparticles tend to increase the total evaporation time. With varying concentrations of graphite at nano scale from 0.02% to 0.18% with an interval at 0.04% in water droplets and the heating temperature from 22 to 85°C, the wetting and evaporation of the sessile droplets are systematically studied with discussion on the impact parameters and the resulted liquid dynamics as well as the stain. The interaction among the phases together with the heating strongly affects the internal circulation inside the droplet, the evaporative rate and the pattern of particles deposition.     

Efficient approximately 2 microm Tm3+ -doped tellurite fiber laser

Laser emission in the range of 1.88-1.99 micrim from a Tm3+ -doped tellurite fiber is demonstrated when pumped with a diode-pumped Er3+/Yb3+-doped silica fiber laser operating at 1.57-1.61 microm. This pump source excites the Tm3+ ions directly into the F43 upper laser level and yields an output power of 280 mW with a slope efficiency of 76% in a 99%-12% laser cavity arrangement and a 32 cm long fiber. This result is very close to the Stokes efficiency limit of approximately 80%. This is, to the authors' knowledge, the first demonstration of high efficiency lasing in a tellurite fiber at wavelengths longer than 1.56 microm.     

Tm(3+)/Ho(3+) codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm(3+)/Ho(3+) codoped tellurite fiber is reported. An Yb(3+)/Er(3+)-doped silica fiber laser operating at 1.6 microm was used as an in-band pump source, exciting the Tm(3+) ions into the (3)F(4) level. Energy is then nonradiatively transferred to the upper laser level, the (5)I(7) state of Ho(3+). The laser transition is from the (5)I(7) level to the (5)I(8) level, and the resulting emission is at 2.1 microm. For continuous wave operation, the slope efficiency was 62% and the threshold 0.1 W; the maximum output demonstrated was 0.16 W. Mechanical Q switching resulted in a pulse of 0.65 microJ energy and 160 ns duration at a repetition rate of 19.4 kHz.     

Quantitative ultra‐high‐performance liquid chromatography–tandem mass spectrometry for determination of dexmedetomidine in pediatric plasma samples: Correlation with genetic polymorphisms

Dexmedetomidine is an important sedative agent administered as premedication to achieve procedural sedation in children. To describe the correlation between the genetic state and the concentration of dexmedetomidine, it is necessary to develop a specific, time‐saving and economical method for detection of dexmedetomidine in plasma samples. In this work, an ultra‐high‐performance liquid chromatography (UHPLC)–tandem mass spectrometry method has been established and validated for detection of dexmedetomidine in plasma from pediatric population. After a simple liquid–liquid extraction with an organic solution, the analytes were separated on an ACQUITY BEH C₁₈ column (2.1 mm × 50 mm, 1.7 μm particle size) by gradient elution with the mobile phase of acetonitrile and 1‰ aqueous formic acid (flow rate 0.3 mL min^?1). Mass spectrometry measurements were performed under the positive selected reaction monitoring and the mass transitions monitored were m/z 201.3 → 95.1, 204.2 → 98.0 for dexmedetomidine and deuterated medetomidine (internal standard), respectively. Validation of the method based on China Food and Drug Administration guidelines showed acceptable selectivity. The UHPLC method employed a stable isotope‐labeled internal standard, showed good specificity and was successfully used to detect dexmedetomidine in plasma samples from 260 pediatric patients. A subsequent application of this method to a pharmacogenetic study was also described. Importantly, this is the first study to report the correlation between CYP2A6 rs835309 activity and concentration of dexmedetomidine.     

To reconstruct a square and a square hole with approximate dimensions

Using unit cell of smaller edge lengths to calculate the initial phases can reduce the size of the initial image.     

Highly efficient alkene epoxidation and aziridination catalyzed by iron(II) salt + 4,4',4'-trichloro-2,2':6',2'-terpyridine/4,4'-dichloro-4'-O-PEG-OCH3-2,2':6',2'-terpyridine

"Iron(II) salt + 4,4',4'-trichloro-2,2':6',2'-terpyridine" is an effective catalyst for epoxidation and aziridination of alkenes and intramolecular amidation of sulfamate esters. The epoxidation of allylic-substituted cycloalkenes achieved excellent diastereoselectivities up to 90%. ESI-MS results supported the formation of iron-oxo and -imido intermediates. Derivitization of Cl 3terpy to O-PEG-OCH 3-Cl 2terpy renders the terpyridine unit to be recyclable, and the "iron(II) salt + 4,4'-dichloro-4'- O-PEG-OCH 3-2,2':6',2'-terpyridine" protocol can be reused without a significant loss of catalytic activity in the alkene epoxidation.     

Conductivity and FTIR studies on PEO-LiX [X: CF3SO3(-), SO4(2-)] polymer electrolytes

Polymer electrolytes based on poly(ethylene oxide)-lithium triflate (PEO-LiCF3SO3) and poly(ethylene oxide)-lithium sulphate (PEO-Li2S4) were prepared by using solution casting method. Measurements of conductivity and dielectric were carried out on these films as a function of frequency at various temperatures. It was observed that PEO-LiCF3SO3 polymer electrolytes have higher conductivity. The interaction between PEO and Li salts were studied by Fourier transform infrared (FTIR).     

SmartBuild-a truly plug-n-play modular microfluidic system

In this Technical Note, for the first time, a truly "plug-n-play" modular microfluidic system (SmartBuild Plug-n-Play Modular Microfluidic System) is presented for designing and building integrated modular microfluidic systems for biological and chemical applications. The modular microfluidic system can be built by connecting multiple microfluidic components together to form a larger integrated system. The SmartBuild System comprises of a motherboard with interconnect channels/grooves, fitting components, microchannel inserts with different configurations and microchips/modules with different functionalities. Also, heaters, micropumps and valving systems can be designed and used in the system. Examples of an integrated mixing system and reaction systems are presented here to demonstrate the versatility of the SmartBuild System.     

Composite Nafion membrane embedded with hybrid nanofillers for promoting direct methanol fuel cell performance

A special type of hybrid nano-particles was incorporated into the Nafion^® matrix to form a composite membrane. These nano-particles possessed a core–shell structure consisting of silica core (<10 nm) and a densely grafted oligomeric ionmer layer, which was synthesized via atom transfer radical polymerization (ATRP) on the particles’ surface. Besides considerable improvement in the proton conductivity of the membrane, the presence of these hybrid nano-particles in the Nafion^® matrix also repressed its methanol permeability by almost four times. The composite membrane also demonstrated superior performance when tested in a single cell membrane-electrolyte assembly (MEA) under direct methanol fuel cell (DMFC) operating condition. It was found that the composite membrane enabled a power density output that was 1.5 times greater than that of pristine Nafion^®.