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Highly monodisperse colloidal InAs quantum dots (QDs) with superior optoelectronic properties are promising candidates for various applications, including infrared photodetectors and photovoltaics. Recently, a synthetic process involving continuous injection has been introduced to synthesize uniformly sized InAs QDs. Still, synthetic efforts to increase the particle size of over 5 nm often suffer from growth suppression. Secondary nucleation or interparticle ripening during the growth accompanies the inhomogeneity in size as well. In this study, we propose a growth model for the continuous synthetic processing of colloidal InAs QDs based on molecular diffusion. The experimentally validated model demonstrates how precursor solution injection reduces monomer flux, limiting particle growth during synthesis. As predicted by our model, we control the diffusion dynamics by tuning reaction volume, precursor concentration, and injection rate of precursor. Through diffusion-dynamics-control in the continuous process, we synthesize the InAs QDs with a size over 9.0-nm (1Smax of 1600 nm) with a narrow size distribution (12.2%). Diffusion-dynamics-controlled synthesis presented in this study effectively manages the monomer flux and thus overcome monomer-reactivity-originating size limit of nanocrystal growth in solution., Monodisperse colloidal InAs quantum dots have been envisioned as Pb-free materials for various infrared applications. Here, the authors provide a growth model based on monomer diffusion dynamics, enabling extended spectral coverage of InAs quantum dots beyond 1Smax of 1600 nm.

We prepared a highly active and stable cathode catalyst for a solid oxide electrolysis cell (SOEC), decorated with in situ exsolved Fe nanoparticles (NPs) socketed on La1.2Sr0.8Mn0.4Fe0.6O4−α (R.P.LSMF), toward the CO2 electrolysis reaction to produce CO selectively. This catalyst was derived from the perovskite structure of La0.6Sr0.4Mn0.2Fe0.8O3−δ (LSMF) by simple annealing in a H2 atmosphere and showed high current densities of 2.04, 1.43, and 0.884 A cm−2 at 850, 800, and 750 °C, respectively, at a voltage of 1.5 V with corresponding total polarization resistance values of 0.205, 0.326, and 0.587 Ω cm2, respectively, at an open circuit voltage. The highly improved performance should be ascribed to the in situ exsolved Fe NPs anchored on Ruddlesden–Popper oxide and to the increased contents of oxygen vacancies in R.P.LSMF. More importantly, this active catalyst also exhibited a stable voltage profile for 100 h operation at an constant current density of 1.8 A cm−2, suggesting that the catalyst Fe–R.P.LSMF proposed in this study is a highly promising candidate for use in an efficient SOEC cathode for CO2 electrolysis processes.

We report a highly improved cathode catalyst by doping fluorine anions in oxygen sites of Ruddlesden-Popper material for CO2 electrolysis to produce CO in solid oxide electrolysis cells (SOECs). Th...

The application of electrocatalysts with high activity to a practical water electrolysis cell is a crucial challenge for the production of pure hydrogen and commercialization of the water electrolyzer. Herein, a nanosized Cu0.5Co2.5O4 catalyst synthesized by co-precipitation by adjusting pH is applied to the anion exchange membrane water electrolysis (AEMWE) cell as an anode, which is demonstrated to have higher efficiency and stability than noble metal-based anodes. The composition (Cu/Co) and morphology of Cu0.5Co2.5O4 change as the pH increases and then nanoparticles are formed at pH 11, where oxygen vacancies are formed by the etching of Cu. In the density functional theory study, the electronic structure of Co modified by Cu in the Co3O4 lattice leads to an optimal adsorption strength, resulting in a free energy diagram in which the potential of Cu0.5Co2.5O4 (1.756 V vs. reversible hydrogen electrode, RHE) is more thermodynamically favorable than that of Co3O4 (1.951 V vs. RHE). The Cu0.5Co2.5O4 catalyst has a recorded overpotential of 285 mV at 10 mA cm−2 in 1 M KOH. Furthermore, the AEMWE cell using Cu0.5Co2.5O4 as an anode exhibited a current density of 1.3 A cm−2 at 1.8 V, which is the highest performance among the reported papers and maintains around 80% energy conversion efficiency for 100 hours.

The selective and efficient electrocatalytic transformation of carbon dioxide (CO2) to multicarbon alcohols (e.g., C2H5OH and C3H7OH) is a challenge in renewable and sustainable energy research. Herein, a series of hybrid catalysts consisting of Cu nanoparticles supported on N-doped porous carbon (Cu/NPC) were prepared. It was demonstrated that the selectivity for C2H5OH or C3H7OH could be tuned by introducing N-doped porous carbon materials as cocatalysts with different pyridinic N contents, which could in situ produce a reactive CO intermediate from CO2. By varying the pyridinic N content, highly selective production of multicarbon alcohols was achieved using the Cu/NPC hybrid catalysts with a high faradaic efficiency for one pot production of multicarbon alcohols up to 73.3% at −1.05 V (vs. RHE). The faradaic efficiency for C2H5OH and C3H7OH was 64.6% and 8.7%, respectively. The pyridinic N species were likely the CO-producing sites and together with Cu catalytic sites acted cooperatively to produce C2H5OH and C3H7OH via a two-site mechanism for efficient CO2 reduction to multicarbon alcohols. These findings provide novel guidance for the rational design of electrocatalysts and for tuning the catalytic activity and selectivity for multicarbon alcohol production from CO2.

We developed a new and efficient sulfur-tolerant catalyst for application as a solid oxide electrolysis cell (SOEC) cathode designed with in situ exsolved CoNi alloy nanoparticles anchored on a Ruddlesden–Popper (R.P.) support of La1.2Sr0.8Co0.4Mn0.6O4 and evaluated its catalytic activity for CO2 electrolysis to CO under a CO2 gas stream containing H2S species. This catalyst was prepared by in situ annealing of a perovskite derivative (La0.6Sr0.4Co0.5Ni0.2Mn0.3O3) in a 20% H2/N2 gas at 800 °C. The catalyst exhibited good reversibility of structural transitions during reduction and re-oxidation processes. A high current density of 703 mA cm−2 was achieved at 1.3 V and 850 °C with a maximum faradaic efficiency of 97.8%. In situ grown CoNi alloy nanoparticles and the high oxygen vacancy content in the R.P. support were responsible for its high catalytic activity and efficiency. Importantly, no sign of performance degradation was observed in galvanostatic tests over a period of 90 h operation under H2S-containing CO2 gas conditions. Moreover, the catalyst showed no noticeable structural changes even after exposure to 100 ppm H2S/N2, indicating that the catalyst developed in this study is highly active for CO2 electrolysis with a high tolerance against sulfur-poisoning species. Therefore, this Ruddlesden–Popper material with in situ exsolved CoNi alloy nanoparticles should be a promising cathode catalyst for practical application to H2S-containing CO2 gas streams that are effluents of power stations or steel making plants.

Converting CO2 into useful chemicals through an electrocatalytic process is an attractive solution to reduce CO2 in the atmosphere. However, the process suffers from high overpotential, low activity, or poor product selectivity. In this study, N,S dual-doped carbon nanoweb (NSCNW) materials were proposed as an efficient nonmetallic electrocatalyst for CO2 reduction. The NSCNW catalysts preferentially and rapidly converted CO2 into CO with a high Faradaic efficiency of 93.4 % and a partial current density of -5.93 mA cm-2 at a low overpotential of 490 mV. A small Tafel slope value (93 mV dec-1 ) was obtained, demonstrating a high rate for CO2 reduction. Moreover, the catalysts also exhibited a quite stable current-density profile during 20 h with a high CO Faradaic efficiency above 90 % throughout the electrolysis reaction. The high catalytic performance of the catalysts for CO2 reduction could be attributed to synergistic effects associated with the structural advantages of 3 D carbon nanoweb structures and effective S doping of the carbon materials with the highest ratio of thiophene-like S to oxidized S species.

We report a highly active Ruddlesden-Popper material with a mechanism of in situ exsolution of Co nanoparticles and its use as an effective catalyst for CO2 reduction to produce CO in a solid oxide electrolysis cell. This catalyst is simply prepared by transforming a perovskite of La0.6Sr0.4Co0.7Mn0.3O3 and revealed a good reversibility of structural transition between the Ruddlesden-Popper and the perovskite structure during reaction cycles. A very high current density of 630 mA/cm2 can be accomplished at a voltage of 1.3 V and temperature of 850 °C with a very high Faraday efficiency of 95% or larger. More importantly, no sign of degradation is indicated as observed by galvanostatic stability test, implying that this Ruddlesden-Popper structure is highly robust as the cathode catalyst for the CO2 electrolysis. In situ exsolved Co nanoparticles and high concentration of oxygen vacancies caused by the structural transition are responsible for its high stability and catalytic activity, as characterized by several physicochemical analyses.

A Cu–Co–P electrocatalyst for hydrogen evolution reaction (HER) was designed with a dendritic and porous foam structure. Fabricated by one-step electrodeposition with binary alloy on a hydrogen bub...

Anthocyanins, water-soluble flavonoids that produce red-to-blue pigment in plants, have antioxidant properties and have been developed as a functional food to fight obesity. In randomized controlled trials (RCTs), a systematic review with meta-analysis (SR-MA) was used to investigate these anti-obesity effects. Using search engines (PubMed, EMBASE, Cochrane-library, and CINAHL) and keywords (anthocyanins, BMI, WC, WHR, and inflammatory biomarkers), 11 out of 642 RCTs (28.3–500 mg/day of anthocyanins for 4 to 24 weeks) were included. The results showed a significant reduction in body mass index (BMI) (MD = −0.36, 95% CI = −0.58 to −0.13), but body weight (BW) and waist circumference (WC) did not change. Anthocyanins decreased BMI in the non-obese (non-OB) group in five RCTs (BMI ≤ 25; MD = −0.40 kg/m2; 95% CI = −0.64 to −0.16;) but did not affect BMI in the obese (OB) group. A subgroup analysis of six RCTs showed that fewer than 300 mg/day reduced BMI (MD = −0.37; 95% CI = −0.06 to −0.14), but ≥300 mg/day did not. A treatment duration of four weeks for four RCTs was sufficient to decrease the BMI (MD = −0.41; 95% CI = −0.66 to −0.16) as opposed to a longer treatment (6–8 or ≥12 weeks). An analysis of the effect of anthocyanins on the BMI showed a significant fall among those from the Middle East compared to those from Asia, Europe, South America, or Oceania. In conclusion, the anthocyanin supplementation of 300 mg/day or less for four weeks was sufficient to reduce the BMI and BW compared to the higher-dose and longer-treatment RCTs. However, further studies might be conducted regarding the dose- or period-dependent responses on various obese biomarkers.

A systematic review and meta-analysis of randomized controlled trials (RCTs) was carried out to assess L-carnitine supplements’ influence on the biomarkers of metabolic syndrome (MetSyn). PubMed, EMBASE, Cochrane library, and CINAHL were used to collect RCT studies published prior to February 2020. RCT studies were included if they had at least one of the following biomarker outcome measurements: waist circumference (WC), blood pressure (BP), fasting blood sugar (FBS), triglyceride (TG), or high density lipoprotein-cholesterol (HDLc). Nine of twenty studies with adequate methodological quality were included in this meta-analysis. The dose of L-carnitine supplementation administered varied between 0.75 and 3 g/day for durations of 8–24 weeks. L-carnitine supplementation significantly reduced WC and systolic BP (SBP), with no significant effects on FBS, TG, and HDLc. We found that L-carnitine supplementation at a dose of more than 1 g/d significantly reduced FBS and TG and increased HDLc. In conclusion, L-carnitine supplementation is correlated with a significant reduction of WC and BP. A dose of 1–3 g/d could improve the biomarkers of MetSyn by reducing FBS and TG and increasing HDLc.

Converting CO2 into valuable chemicals using electrocatalysis is an attractive approach for sustainable energy storage and artificial carbon cycle. In this study, atomically dispersed Ir species (Ad-Ir) that are supported on three-dimensional (3D) porous carbon networks are proposed as electrocatalysts for highly efficient CO2 conversion. The resulting catalysts can preferentially and rapidly produce CO with a high Faradaic efficiency of 95.6 % and a very high turnover frequency (TOF) value of 33,365 h−1. Furthermore, it shows no obvious decay in both FE for CO and current density over 20 h of continuous operation. Based on detailed experimental studies and density functional theory (DFT) calculations, such outstanding catalytic performance for CO2 conversion to CO production can be attributed to the structural advantages of 3D network of porous carbon and atomically dispersed Ir species on the 3D carbon support.

In this study, a highly efficient Pd catalyst supported on a conducting polymer-carbon composite was prepared for electro-oxidations of ethanol and formic acid. A polypyrrole-carbon composite was synthesized and modified by doping camphor sulfonic acid (CSA) during the polymerization step of pyrrole at room temperature. The resulting CSA-doped polypyrrole-carbon composite (PPyCC) showed significantly increased specific surface area and enhanced electrical conductivity compared with a polypyrrole-carbon composite without doping (PPyC). From the electrochemical tests, it was observed that the Pd-supported on CSA-doped polypyrrole-carbon composite (Pd/PPyCC) exhibited much larger electrochemical surface area (ECSA), enhanced catalytic activity and high durability towards the oxidations of ethanol and formic acid. The results indicate that the camphor sulfonic acid serving as both dopant and surfactant could improve the electrical conductivity and morphology of support material with enhanced interaction between Pd nanoparticles and support material.

The ladder-like polysilsesquioxanes containing both the bio-mimicking adhesive polycatechol and polyethylene oxide (CA-PEO-LPSQ) were synthesized as an organic-inorganic hybrid material and applied as a surface modifier for the preparation of a compatible polyethylene (PE) separator in high performing lithium ion batteries (LIBs). The dip-coating of CA-PEO-LPSQ onto PE (PE-M) separator was optimized at different alkaline pH values. The PE-M separator contained an inorganic ladder-like polysilsesquioxane-based backbone chain with organic moieties PEO and catechol acting as functional groups for enhancing the surface wettability, lithium ion conductivity, and thermal and electrochemical stability. The LIBs fabricated using PE-M as the separator, LiCoO2 as the cathode, and Li metal foil as the anode showed excellent capacity retention of 96% and 82% after the first cycle and 300th cycle at 0.5C rate, respectively, when compared to bare a PE separator exhibiting 95% and 15%, respectively.

A highly stable electrode material of Ruddlesden–Popper structure, La1.2Sr0.8Mn0.4Fe0.6O4 (RPLSMF), is prepared from La0.6Sr0.4Mn0.2Fe0.8O3 (LSMF) perovskite by in situ annealing in flowing H2 at the operation temperature of solid oxide fuel cells. The crystallinity, morphology, and oxidation states of each element and electrochemical properties of RPLSMF are characterized. Doping Mn into the B-site of RPLSMF improves the phase stability of the structure in H2 to prevent formation of La2O3. The XPS results also suggest that improved phase stability promotes formation of Fe2+/3+ pairs that facilitate fuel oxidation by redox coupling. Additionally, during phase transition to RPLSMF, metallic Fe nanoparticles form, which enlarge H2 chemisorption and oxidation sites. Consequently, RPLSMF exhibits outstanding and stable electrochemical activity with a maximum power density of 0.72 W cm−2 at 1073 K when used as an anode material in LSGM electrolyte-supported cells. As the phase transition between the RPLSMF and LSMF is reversible under a redox environment, RPLSMF/GDC is applied as an electrode in the symmetrical cell of RPLSMF-GDC/LSGM/LSMF-GDC. It exhibits a substantial power density of 0.64 W cm−2 with a total polarization resistance of 0.51 Ω cm2.

A replacement technique has been regarded as a promising strategy for both CH4 exploitation from gas hydrates and CO2 sequestration into deep-ocean reservoirs. Most research has been focused on replacement reactions that occur in sI hydrates due to their prevalence in natural gas hydrates. However, sII hydrates in nature have been also discovered in some regions, and the replacement mechanism in sII hydrates significantly differs from that in sI hydrates. In this study, we have intensively investigated the replacement reaction of sII (C3H8 + CH4) hydrate by externally injecting CO2/N2 (50:50) gas mixture with a primary focus on powder X-ray diffraction, Raman spectroscopy, NMR spectroscopy, and gas chromatography analyses. In particular, it was firstly confirmed that there was no structural transformation during the replacement of C3H8 + CH4 hydrate with CO2/N2 gas injection, indicating that sII hydrate decomposition followed by sI hydrate formation did not occur. Furthermore, the cage-specific replacement pattern of the C3H8 + CH4 hydrate revealed that CH4 replacement with N2 in the small cages of sII was more significant than C3H8 replacement with CO2 in the large cages of sII. The total extent of the replacement for the C3H8 + CH4 hydrate was cross-checked by NMR and GC analyses and found to be approximately 54%. Compared to the replacement for CH4 hydrate with CO2/N2 gas, the lower extent of the replacement for the C3H8 + CH4 hydrate with CO2/N2 gas was attributable to the persistent presence of C3H8 in the large cages and the lower content of N2 in the feed gas. The structural sustainability and cage-specific replacement observed in the C3H8 + CH4 hydrate with external CO2/N2 gas will have significant implications for suggesting target gas hydrate reservoirs and understanding the precise nature of guest exchange in gas hydrates for both safe natural gas production and long-term CO2 sequestration.

Recently, oxygen vacancy engineering represents a new direction for rational design of high-performance catalysts for electrochemical CO2 reduction (CO2RR). In this work, a series of amorphous MnOx catalysts with different concentrations of oxygen vacancies, namely, low (a-MnOx-L), pristine (a-MnOx-P), and high oxygen vacancy (a-MnOx-H), have been prepared by simple plasma treatments. The resultant a-MnOx-H catalyst with a larger amount of oxygen vacancy on the catalyst surface is able to preferentially convert CO2 to CO with a high Faradaic efficiency of 94.8% and a partial current density of 10.4 mA cm−2 even at a relatively lower overpotential of 510 mV. On the basis of detailed experimental results and theoretical density functional theory (DFT) calculations, the enhancement of CO production is attributable to the abundant oxygen vacancies formed in the amorphous MnOx which should favor CO2 adsorption/activation and promote charge transfer with the catalyst for efficient CO2 reduction.

Coke-resistant Ni catalyst supports are evaluated for steam reforming (SR) n-dodecane, the alkane used as a surrogate for diesel fuel in this study. Reactions are conducted at 800 °C for 5 h, with a molar steam-to-carbon ratio of 3.0 and a gas hourly space velocity of 20000 h−1. Thermally stable, coke-resistant supports loaded with 15 wt% Ni are prepared using the following potassium oxides: K2Ti2O5 (KTI), K4Zr5O12 (KZR), KNbO3 (KNB), KTaO3 (KTA), and K2WO4 (KW). Ni/KZR and Ni/KW show the best catalytic performance in the SR reaction due to their moderate-to-strong acidities and lack of porosity, which are necessary features for hydrocarbon cracking. Unfortunately, these catalysts are poorly stable under the defined operating conditions. KNB is the most suitable support due to its excellent thermal stability and coke-resistance; however, it lacks acidity. The acidity of KNB is enhanced by impregnation with ZrO2, which transforms it into an acidic oxide (ZR-KNB). ZR-KNB features high thermal stability and high coke-resistance during the SR of n-dodecane under the applied test conditions. The Ni/ZR-KNB catalyst delivers excellent SR performance with respect to both n-dodecane conversion and hydrogen selectivity.

Metal-free catalysts have gained substantial attention as a promising candidate to replace the expensive platinum (Pt) catalysts for the oxygen reduction reaction (ORR) which is a key process in low temperature fuel cells. Development of highly efficient and mass-producible N-doped carbon catalysts, however, remains to be a great challenge. In this study, N-doped porous carbon (NPC) materials were synthesized via a simple, cost-effective and scalable method for mass production by using the D-gluconic acid sodium salt, pyrrole, Triton X-100 and KOH. The resulting NPC possessed a multidirectional porous carbon network (SBET: 1026.6 m2 g−1, Vt: 1.046 cm3 g−1) with hierarchical porosity and plenty of graphitic N species (49.1%). Electrochemical tests showed that the NPC itself was highly active for the ORR under alkaline and acidic conditions via a four electron pathway for the complete reduction of O2 in water. More importantly, this NPC catalyst demonstrated better performance than commercial Pt/C catalysts in terms of long-term durability and methanol tolerance under both conditions.

A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g−1 at a scan rate of 5 mV s−1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg−1 at power density of 495 W kg−1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future.

Herein, we show that DNA nanostructures have great potential as templates for the synthesis of shape-controlled metal nanostructures. In specific, branch-shaped gold nanostructures, which show broad absorption in near the infrared region and have high efficacy in photothermal cancer cell treatment, have been successfully synthesized by using X-shaped and Y-shaped DNA as templates.

4-methylmorpholine (4-mMPL), a nitrogen-containing heterocyclic compound, is an organic base which acts as a proton acceptor. In this study, we characterized structure H (sH) clathrate hydrates with 4-mMPL by measuring the hydrate-phase equilibria and a series of microscopic analyzes (powder X-ray diffraction, solid-state 13C NMR and Raman spectroscopy). 4-mMPL was found to have lower dissociation temperature at a given pressure compared to that of pure CH4 hydrate, simultaneously with a co-guest in sH hydrates (hexagonal P6/mmm). Such a change of thermodynamic stability is attributed to an oxygen atom in the molecular structure of 4-mMPL, which prevents hydrogen-bonding among water molecules. The ratio of the molecular diameter to cage diameter is 0.87, implying that the guest molecules can fit into cavities without distortion. The thermodynamic and chemical characteristics of 4-mMPL can be extended to other guest species in order to explain molecular behaviors related to inherent mechanisms of hydrate stability and host-guest interactions.

A colorimetric sensor array was developed to characterize and quantify the taste of white wines. A charge-coupled device (CCD) camera captured images of the sensor array from 23 different white wine samples, and the change in the R, G, B color components from the control were analyzed by principal component analysis. Additionally, high performance liquid chromatography (HPLC) was used to analyze the chemical components of each wine sample responsible for its taste. A two-dimensional score plot was created with 23 data points. It revealed clusters created from the same type of grape, and trends of sweetness, sourness, and astringency were mapped. An artificial neural network model was developed to predict the degree of sweetness, sourness, and astringency of the white wines. The coefficients of determination (R-2) for the HPLC results and the sweetness, sourness, and astringency were 0.96, 0.95, and 0.83, respectively. This research could provide a simple and low-cost but sensitive taste prediction system, and, by helping consumer selection, will be able to have a positive effect on the wine industry.

Guest–host hydrogen bonding strongly affects the physical properties of clathrate hydrate, such as the thermodynamic stability, water dynamics, and dielectric properties, but attempts to quantify the effects of hydrogen bonding on these properties are rare thus far. As a preliminary work, this study investigates methane clathrate hydrates with three diazine isomers, pyrazine, pyrimidine, and pyridazine, which expect nearly the same van der Waals volumes due to their similar molecular shapes and sizes, and their guest–host hydrogen-bonding behaviors. The crystal structures of all three binary diazine + CH4 hydrate phases were identified as a cubic Fd3m structure, including diazine molecules in the 51264 cavity, commonly termed as structure II hydrate, by a high-resolution powder diffraction pattern analysis. The phase equilibrium curves of their clathrate hydrates were obtained by the P–T trajectory of the hydrate formation and dissociation process, and the thermodynamic stability trend was well-explained...

Optical trapping of nanometer-sized lipid vesicles has been challenging due to the low refractive index contrast of the thin lipid bilayer to the aqueous medium. Using an "optical bottle", a recently developed technique to measure interactions of nanoparticles trapped by an infrared laser, we report, for the first time, quantitative measurements of the trapping energy of charged lipid vesicles. We found that the trapping energy increases with the relative amount of anionic lipids (DOPG) to neutral lipids (DOPC) in vesicles. Moreover, as monovalent salt is added into the exterior solution of vesicles, the trapping energy rapidly approaches zero, and this decrease in trapping energy strongly depends on the amount of anionic lipids in vesicles. A simple model with our experimental observations explains that the trapping energy of charged lipid vesicles is highly correlated with the surface charge density and electric double layer. In addition, we demonstrated selective trapping of a binary mixture of vesicles in different mole fractions of charged lipids, a strategy that has potential implications on charge selective vesicle sorting for engineering applications.

The unexpected formation of gas hydrates during production and transportation processes in petroleum industries is known as a serious problem. To deal with this problem, the oil and gas industry has been searching for hydrate inhibitors that have great performance and cost effectiveness. Recently, ionic liquids (ILs) have been suggested as novel hydrate inhibitors that are able to act in both thermodynamic and kinetic ways (so-called dual-function inhibitors). In this paper, we suggest a non-ionic liquid compound, morpholine, as a dual-function inhibitor by measuring hydrate-phase equilibria and a series of microscopic analyses [powder X-ray diffraction, solid-state 13C nuclear magnetic resonance (NMR), and Raman spectroscopy]. Moreover, the formation kinetics of gas hydrates in the presence of morpholine was found to be better than two comparators, 1-ethyl-3-methylimidazolium tetrafluoroborate and polyvinylpyrrolidone. Such inhibition effects of morpholine are thought to be mainly attributed to the nucle...

The physical properties of semi-clathrate hydrates formed with tetra- n -butylammonium fluoride (TBAF) and tetra- n -butylammonium bromide (TBAB) in the temperature range of 83–263 K were studied using terahertz time-domain spectroscopy (THz-TDS). From our measurements, the semi-clathrate hydrate of TBAF shows the general trend of slightly higher refractive indices than the TBAB semi-clathrate hydrate. Furthermore, significant differences in the absorption coefficients and dielectric constants between the TBAF and TBAB semi-clathrate hydrates are discovered. These originate from fundamental structural/compositional differences between the hydrates which are related to their gas storage capacities.

Microfluidic devices have been extensively developed as methods for microscale materials fabrication. It has also been adopted for polymeric microsphere fabrication and in situ drug encapsulation. Here, we employed multi-inlet microfluidic channels for DNA hydrogel microsphere formation and in situ protein encapsulation. The release of encapsulated proteins from DNA hydrogels showed different profiles accordingly with the size of microspheres.

Diethylamine and n-propylamine, known as semiclathrate hydrate formers, are found to show structural transition when a help gas, CH4, was introduced. The diethylamine·8.67H2O semiclathrate hydrates (orthorhombic Pbcn) were changed to sH type (hexagonal P6/mmm) true clathrate hydrates, while the n-propylamine·6.5H2O semiclathrate hydrates (monoclinic P21/n) turned into sII clathrate hydrates (cubic Fd3m). Irregularly distorted voids in the semiclathrate hydrate phases were transformed to conventional ones after changing their structures to gas hydrate phases. The different shape of large voids in the semiclathrate hydrates changed to the typical shape of sH or sII large voids, and pentagonal dodecahedra were formed so as to capture CH4 molecules. Transition pattern and molecular behavior from semiclathrate hydrate to true clathrate hydrates were analyzed with PXRD, NMR, and Raman methods. In addition, the liquid mixture−CH4 hydrates−CH4 vapor (L−H−V) thermodynamic equilibrium conditions were measured.

The coupling reaction between 5-bromo-3-phenylbenzo[c]isoxazole and diphenylamine followed by further condensation with a mono-, di- or ter-acetyl aromatic compound in the presence of diphenyl phosphate at 145 o C gave a novel asymmetric diarylquinolines, oligoquinolines with diphenylamine endgroups, and a first generation quinoline dendrimer in 41-82% isolated yield. The electrochemical and photophysical properties of the oligoquinolines were characterized by cyclic voltammograms (CVs) and spectroscopy. All the quinolines emit bright sky blue light due to charge transfer from quinoline group to diphenly amine with very high quantum efficiency (> 90%). Organic light-emitting diodes (OLEDs) were fabricated using these quinolines as emitting materials. Among different device architectures explored, OLEDs with a structure of ITO/PEDOT (40 nm)/TAPC (15 nm)/D-A quinoline (40 nm)/TPBI (30 nm)/LiF (1 nm)/Al using TAPC as an electron blocking layer and TPBI as a hole blocking layer gave the best performance. A high external quantum efficiency in the range of 1.2-2.3% were achieved in all the quinolines with the best performance in BBQA(5). Our results indicate diarylamino-substituted oligoquinoline and dendrimer are promising materials for OLEDs applications.

We suggest two types of new amine-type sII formers: pyrrolidine and piperidine. These guest compounds fail to form clathrate hydrate structures with host water, but instead have to combine with light gaseous guest molecules (methane) for enclathration. First, two binary clathrate hydrates of (pyrrolidine + methane) and (piperidine + methane) were synthesized at various amine concentrations. 13C NMR and Raman analysis were done to identify the clathrate hydrate structure and guest distribution over sII-S and sII-L cages. XRD was also used to find the exact structure and corresponding cell parameters. At a dilute pyrrolidine concentration of less than 5.56 mol%, the tuning phenomenon is observed such that methane molecules surprisingly occupy sII-L cages. At the critical guest concentration of about 0.1 mol%, the cage occupancy ratio reaches the maximum of approximately 0.5. At very dilute guest concentration below 0.1 mol%, the methane molecules fail to occupy large cages on account of their rarefied distribution in the network. Direct-release experiments were performed to determine the actual guest compositions in the clathrate hydrate phases. Finally, we measured the clathrate hydrate phase equilibria of (pyrrolidine + methane) and (piperidine + methane).

Hexamethyleneimine, 1-methylpiperidine, 2-methylpiperidine, 3-methylpiperidine, and 4-methylpiperidine as isomers of C6H13N were revealed as new sH clathrate hydrate forming molecules. They show fu...

We present a novel method, an optical bottle, that uses a focused laser beam to trap and a second laser to analyze optically confined multiple nanoparticles. A theoretical framework based on the mechanical equilibrium of the optical radiation pressure produced by the focused laser beam and the osmotic pressure produced by the enriched particle concentration in the optical trap is developed for analyzing the ensemble behavior of the optically confined nanoparticles. Experiments were conducted for fluorescently labeled polystyrene nanospheres and unilamellar phospholipid vesicles to determine the optical trapping energy of individual particles as well as the osmotic compressibility of the colloids. The new method is not limited by the particle concentration and is relatively easy to implement.

The stability of hydrate frameworks is influenced by guest molecules capable of hydrogen bonding with surrounding water molecules. Four remarkable features from the ammonium fluoride incorporation into a crystalline hydrate matrix provide important information on the thermodynamic stability, formation kinetics, structural characteristics, and molecular behavior in clathrate hydrate systems.

The chemical behavior of major inorganic ions in the streams of the Mankyung River area (South Korea) was investigated. Mixing with effluent from the Jeonju STP (a municipal sewage treatment plant in Jeonju City) was the most important process in regulating the water chemistry of the streams. The effluent was chemically distinct relative to the stream waters in inorganic composition. Behavior of various ions was evaluated by comparing their concentrations with the concentration of chloride, a conservative chemical species. It was revealed that concentrations of chloride and sulfate, the total concentration of major cations, and electrical conductivity in the stream were controlled only by mixing, indicating their conservative behavior similar to chloride. Alkalinity and concentration of nitrate, however, were regulated by various reactions such as mixing, photosynthesis, respiration, and decomposition of organic matter. Streamflows were estimated by observing chemical composition of the effluent and those of up/downstream waters. Estimated flows based on the conservative chemical parameters were nearly the same as those directly measured using an area–velocity method, indicating the validity of the chemistry-based method.

The structures and the guest-host distributions of iso-propylamine (i-PA) and n-propylamine (n-PA) hydrates with hydrogen as a secondary guest were identified by powder X-ray diffraction and Raman spectroscopic analysis. The structure of 11.1 mol% i-PA + H2 hydrate was identified to be hexagonal (space group P63/mmc) with a few unindexed diffraction peaks, while 5.6 mol% i-PA + H2 hydrate had a cubic structure (space group Fd3¯m). Similarly, the structure of 13.3 mol% n-PA + H2 hydrate was found to be monoclinic (space group P2(1)/n), while 5.6 mol% n-PA + H2 hydrate had a cubic structure (space group Fd3¯m). The 'tuning' phenomenon, multiple occupancy of hydrogen in the large cage at the pressure and temperature regions outside of pure hydrogen hydrate stability, was observed in the i-PA + H2 hydrate only when the amine concentration was lower than the stoichiometric value of structure II hydrate. The three-phase (H-L(w)-V) equilibria for alkylamine + H2 + water mixtures were also measured to investigate their thermodynamic stability.

Herein, we suggest a new approach to an electric double-layer capacitor (EDLC) that is based on a proton-conducting ionic clathrate hydrate (ICH). The ice-like structures of clathrate hydrates, which are comprised of host water molecules and guest ions, make them suitable for applications in EDLC electrolytes, owing to their high proton conductivities and thermal stabilities. The carbon materials in the ICH Me4NOH⋅5 H2O show a high specific capacitance, reversible charge-discharge behavior, and a long cycle life. The ionic-hydrate complex provides the following advantages in comparison with conventional aqueous and polymer electrolytes: 1) The ICH does not cause leakage problems under normal EDLC operating conditions. 2) The hydrate material can be utilized itself, without requiring any pre-treatments or activation for proton conduction, thus shortening the preparation procedure of the EDLC. 3) The crystallization of the ICH makes it possible to tailor practical EDLC dimensions because of its fluidity as a liquid hydrate. 4) The hydrate solid electrolyte exhibits more-favorable electrochemical stability than aqueous and polymer electrolytes. Therefore, ICH materials are expected to find practical applications in versatile energy devices that incorporate electrochemical systems.

The metal complex of [Co(NH 3 ) 6 ] 3+ is introduced to C 2 H 6 hydrate to confirm its possible inclusion in hydrogen-bonded water cages and the occurrence of metastable structure. The 13 C NMR spectra of C 2 H 6 +([Co(NH 3 ) 6 ]Cl 3 + 6NaOH in D 2 O) hydrate confirmed a new peak at 6.5 ppm matching with C 2 H 6 in sII-L cages. The retarded appearance of metastable sII phase is due to brine rejection of the cobalt complex occurring during solution freezing. The anions of OH and F were found to be incorporated in the host water cage framework, providing proton-deficient sites. The ionic conductivity of the frozen [Co(NH 3 ) 6 ] 3+ solution increased up to 20-fold after ethane hydrate formation, implying the incorporation of F ― into the host lattice. A notable finding of this work is that the metastability occurs only when the cobalt complex is in the presence of anions such as OH ― and F ― .