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As the skin is the largest body organ and critically serves as a barrier, it is frequently exposed and could be physiologically affected by radiofrequency electromagnetic field (RF-EMF) exposure. In this study, we found that 1760 MHz RF-EMF (4.0 W/kg specific absorption rate for 2 h/day during 4 days) exposure could induce intracellular reactive oxygen species (ROS) production in HaCaT human keratinocytes using 2′,7′-dichlorofluorescin diacetate fluorescent probe analysis. However, cell growth and viability were unaffected by RF-EMF exposure. Since oxidative stress in the skin greatly influences the skin-aging process, we analyzed the skin senescence-related factors activated by ROS generation. Matrix metalloproteinases 1, 3, and 7 (MMP1, MMP3, and MMP7), the main skin wrinkle-related proteins, were significantly increased in HaCaT cells after RF-EMF exposure. Additionally, the gelatinolytic activities of secreted MMP2 and MMP9 were also increased by RF-EMF exposure. FoxO3a (Ser318/321) and ERK1/2 (Thr 202/Tyr 204) phosphorylation levels were significantly increased by RF-EMF exposure. However, Bcl2 and Bax expression levels were not significantly changed, indicating that the apoptotic pathway was not activated in keratinocytes following RF-EMF exposure. In summary, our findings show that exposure to 1760 MHz RF-EMF induces ROS generation, leading to MMP activation and FoxO3a and ERK1/2 phosphorylation. These data suggest that RF-EMF exposure induces cellular senescence of skin cells through ROS induction in HaCaT human keratinocytes.

Self-assembly of two-dimensional MXene sheets is used in various fields to create multiscale structures due to their electrical, mechanical, and chemical properties. In principle, MXene nanosheets are assembled by molecular interactions, including hydrogen bonds, electrostatic interactions, and van der Waals forces. This study describes how MXene colloid nanosheets can form self-supporting MXene hydrogels. Three-dimensional network structures of MXene gels are strengthened by reinforced electrostatic interactions between nanosheets. Stable gel networks are beneficial for fabricating highly aligned fibers because MXene gel can endure structural deformation. During wet spinning of highly concentrated MXene colloids in a coagulation bath, MXene sheets can be transformed into perfectly aligned fibers under a mechanical drawing force. Oriented MXene fibers exhibit a 1.5-fold increase in electrical conductivity (12 504 S cm-1) and Young's modulus (122 GPa) compared with other fibers. The oriented MXene fibers are expected to have widespread applications, including electrical wiring and signal transmission.

Background To investigate the surgical outcomes of implantable collamer lens (ICL) implantation in eyes with residual myopia after primary laser vision correction (LVC) surgeries. Methods This study included patients who underwent ICL implantation and had a history of LVC surgery, including photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK). Visual acuity and refractive error were assessed pre and 3-months postoperatively and the efficacy and safety indices calculated accordingly. Results A total of 30 eyes of 17 patients were included in this study. At 3 months, the mean logMAR uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalent were − 0.03 ± 0.11 (include logMAR), − 0.04 ± 0.09 (include logMAR), and − 0.06 ± 0.33 diopters (D), respectively. The 3-month Snellen UDVA was better than 20/20 for 83% of eyes, and 97% of eyes showed an unchanged or improved CDVA after surgery. The mean efficacy and safety indices were 1.11 ± 0.22 and 1.13 ± 0.20, respectively. Further, 93 and 100% of eyes were within ±0.5 and ± 1.0 D of the attempted spherical equivalent refraction, respectively. Conclusions ICL implantation in eyes with myopic regression after previous LVC surgery showed safe, effective, and predictable outcomes. Trial registration retrospectively registered.

Inspired by the role of cellular structures, which give three-dimensional robustness to graphene structures, a new type of graphene cantilever with mechanical resilience is introduced. Here, NH4SCN...

Crystalline silica nanoparticles exhibit superior physical properties to amorphous phase when incorporated in nanocomposites. In this paper, we introduce the crystalline silica nanoparticles–embedded nanocomposites (CSN–nanocomposite) as a high-performance insulation material, and discuss their improved macro/microscopic properties according to the CSN contents. Monodisperse CSN particles (50 nm in size) are produced via facile and cost-effective top-down grinding methods, and their surfaces are modified with organic ligands to endure homogeneous dispersion and chemical crosslinking with epoxy matrix. With the aid of optimal hybridization of the CSN and the matrix, the CSN–nanocomposite exhibits high optical transparency, enhanced mechanical strength, increased thermal conductivity, and improved electrical insulating property.

Over the past few years, several nanofluidic channels have been constructed using ion-conductive materials. However, the design and fabrication of surface-charge-controllable nanochannels remain a scientific as well as a technological challenge. This study investigated the feasibility of graphene oxide (GO)-based fiber-type nanochannels for generating electrical energy by converting the salinity gradient. Owing to their large lateral size and the localized charged species on the edge, the low charge density of the GO fibers remains a critical bottleneck in their wider investigation. To address this critical issue, highly negatively charged and extremely small (2.42 ± 0.38 nm) graphene quantum dots (GQDs) were synthesized and intercalated through the interstitial network of GO sheets in fibers. With the application of GQDs, the charge density was significantly increased to 1.12 mC m−2 so that the ion conductance was enhanced to an average of 21 nS and the electrical energy generation was 0.25 W m−2. This study presents a facile and novel approach of enhancing ion selectivity and ion conductivity of graphene-fiber based miniaturized nanofluidic channels, proving their potential for osmotic energy generation and efficiency.

We report the development of a class-II-type hybrid coating (NS-EP hybrid) composed of surface-modified nanosilica (NS) as the filler and a thermo-curable epoxy polymer (EP) as the matrix. NS is synthesized using a hydrolytic sol-gel process; its hydroxyl surface is rendered cross-linkable using glycidyl ligands to ensure homogeneous dispersion and optimal hybridization with the EP matrix. The NS-EP hybrid shows high optical transparency, enhanced mechanical properties, and improved moisture barrier performance. Further, we discuss the physical properties of the hybrid with respect to the NS content. To study the applicability of the hybrid as a high-performance barrier material in practical applications, an actual OLED device is encapsulated using the hybrid.

We report the facile fabrication of transparent and high-performance moisture barrier material (SC nanocomposite) using surface-modified bentonite clay (SC) as nanofiller and glycidyl silane as a surface-modifier/binder via simple, cost-effective and mass-producible process. SC is synthesised using a base-catalysed sol-gel process; their hydroxyl surfaces are decorated with glycidyl ligands to endure the densely stacked structure and high clay content in the final nanocomposite. The SC nanocomposite barrier exhibits high optical transparency (>90), dense multi-stacked clay structure, and considerably enhanced moisture barrier performance. We discuss the fabrication and physical properties of the SC nanocomposite. To assess the applicability of the nanocomposite as a high-performance barrier material in practical applications, typical organic light-emitting devices are encapsulated, and their lifetime is evaluated.

The conversion of the electrokinetic energy arising from evaporation-induced water flow through nanoporous materials has great potential for renewable energy production. In this study, we prepare a nanocapillary membrane containing both nanopores and nanochannels based on an assembly of holey graphene oxide (HGO) nanosheets, which enables water molecules to permeate and simultaneously evaporate from the nanostructure. In particular, we find that the performance of our HGO membrane-based water evaporation-induced energy harvester (WEEH) can be significantly improved by ensuring (1) a high capillary flow of water through low-friction nanochannels and (2) a high rate of evaporation, which is achieved by the presence of large nanoscale pores with a broad size distribution. Our WEEH yields a maximum voltage of 0.44 V, current of 200 nA, and output energy density of 2.2 μWh cm−2. Furthermore, the use of multiple WEEHs allows for the generation of sufficient energy to charge a 1-F supercapacitor and power a light-emitting diode (2 V × 20 mA). Thus, our proposed nanocapillary, thin-membrane-based WEEH has great practical potential for energy generation, as well as other membrane-based technologies such as water purification.

We report on the synthesis of a silica nanoparticle-embedded epoxy nanohybrid (SNP-EP nanocomposite), that can be used as a robust transparent encapsulation material for various applications. The SNP-EP nanocomposite is composed of a thermo-curable, bisphenol A-type epoxy polymer as a matrix and monodispersed silica nanoparticle (SNP) as a reinforcement, which can create tortuous diffusion path for moisture penetrants. SNP is synthesized via a base-catalyzed hydrolytic sol-gel condensation, and the surface of the SNP is modified with glycidyl and phenyl ligands to endure stable dispersion and chemical cross-linking with epoxy matrix. The SNP-EP nanocomposite exhibits significantly enhanced water vapor transmission rate of 1.52 g/m 2 day and an optical transparency over 90% in the visible range with strong adhesion (5B). We introduce synthetic steps of the nanocomposite and discuss physical/chemical properties of the composite.

Here, we report on the synthesis of a silica nanoparticle (NP)-reinforced oligosiloxane nanohybrid material (SM-nanocomposite) and demonstrate its properties as a robust transparent hard coating material for various applications. The oligosiloxane (MMO) resin as a matrix was synthesized using methyl and methacryl silanes via a hydrolytic sol-gel condensation. The silica NPs with various sizes (12, 20 and 60 nm) as nanofillers were also synthesized through a hydrolytic sol-gel condensation, and the surface of NPs was organically modified with methyl and methacryl functions, which allowed stable dispersion and chemical cross-linking of the NPs with MMO matrix. In this work, we introduce synthetic steps of the nanocomposite and discuss the optical, morphological, thermal and mechanical properties of the composite.

Ti3C2Tx MXene is an emerging class of two-dimensional nanomaterials with exceptional electroconductivity and electrochemical properties, and is promising in the manufacturing of multifunctional macroscopic materials and nanomaterials. Herein, we develop a straightforward, continuously controlled, additive/binder-free method to fabricate pure MXene fibers via a large-scale wet-spinning assembly. Our MXene sheets (with an average lateral size of 5.11 μm2) are highly concentrated in water and do not form aggregates or undergo phase separation. Introducing ammonium ions during the coagulation process successfully assembles MXene sheets into flexible, meter-long fibers with very high electrical conductivity (7,713 S cm−1). The fabricated MXene fibers are comprehensively integrated by using them in electrical wires to switch on a light-emitting diode light and transmit electrical signals to earphones to demonstrate their application in electrical devices. Our wet-spinning strategy provides an approach for continuous mass production of MXene fibers for high-performance, next-generation, and wearable electronic devices., Large-scale production of fibers from two dimensional materials opens a pathway to promising applications. Here the authors report meter-long MXene fibers with high electrical conductivity that are fabricated via continuous wet spinning and demonstrated in electrical wires.

Here, we report on the synthesis of a silica nanoparticle (SNP)-embedded urethane acrylate (UA) nanohybrid material (SNP-UA) and demonstrate its performance as photo-patternable transparent hard coating for optical applications. The SNP (10–20 nm) were synthesized via a base-catalyzed sol-gel condensation and the surface of SNP was chemically modified with methyl and methacryl organic functions by simple and mild solution processes, which not only enabled complete dispersion of SNP in the UA matrix but also rendered chemically cross-linked hybrid network of the SNP-UA. As an UV-curable optical hard coating, the SNP-UA exhibited excellent optical transparency coupled with a tunability of refractive index, good anti-scratch performance, and photo-patternability.

With the rapid growth of wireless communication devices, the influences of electromagnetic fields (EMF) on human health are gathering increasing attention. Since the skin is the largest organ of the body and is located at the outermost layer, it is considered a major target for the health effects of EMF. Skin pigmentation represents one of the most frequent symptoms caused by various non-ionizing radiations, including ultraviolet radiation, blue light, infrared, and extremely low frequency (ELF). Here, we investigated the effects of EMFs with long-term evolution (LTE, 1.762 GHz) and 5G (28 GHz) bandwidth on skin pigmentation in vitro. Murine and Human melanoma cells (B16F10 and MNT-1) were exposed to either LTE or 5G for 4 h per day, which is considered the upper bound of average smartphone use time. It was shown that neither LTE nor 5G exposure induced significant effects on cell viability or pigmentation. The dendrites of MNT-1 were neither lengthened nor regressed after EMF exposure. Skin pigmentation effects of EMFs were further examined in the human keratinocyte cell line (MNT-1-HaCaT) co-culture system, which confirmed the absence of significant hyper-pigmentation effects of LTE and 5G EMFs. Lastly, MelanoDerm&trade, a 3D pigmented human epidermis model, was irradiated with LTE (1.762 GHz) or 5G (28 GHz), and image analysis and special staining were performed. No changes in the brightness of MelanoDerm&trade, tissues were observed in LTE- or 5G-exposed tissues, except for only minimal changes in the size of melanocytes. Collectively, these results imply that exposure to LTE and 5G EMFs may not affect melanin synthesis or skin pigmentation under normal smartphone use condition.

The ZrO2-sol was prepared with zirconium acetate and water below 60°C followed by the modification with 0, 0.5 and 5 mol of methyltrimethoxysilane(MTMS) via sol-gel method. The epoxy system was consisted of 1,1,1-(triglycidyl-oxyphenyl) methane, (3-4-epoxycyclohexane) methyl-3-4-epoxycyclohexyl carboxylate, methyl-2,3-norbornanedicarboxylic anhybride, ethyl triphenyl phosphonium iodide and N,N-dimethylacetamide (DMAc). The epoxy system and MTMS-modified ZrO2-sols were mixed to be solid contents of 90 : 10 weight percentages. ZrO2 particles synthesized from sol-gel method were amorphous phase in XRD patterns. FE-SEM images showed MTMS-modified ZrO2 particles were dispersed with excellent homogeneity in hybrid system. The FT-IR spectra of MTMS-modified ZrO2 particle identified the methyl and silica groups formed from MTMS on the surface of ZrO2 particle. It is considered that epoxy-ZrO2 hybrid materials have the potential to be used as the hybrid thin film due to their high refractive index and excellent hy...

The characteristics of organic-inorganic hybrid coatings that were prepared well from surfacemodified silicate sols were studied. The surface-modified silicate sols were fabricated in a two-step sol-gel process involving nano-silicates and silanes by varying the type of silane and the reaction time. The synthesized oraganosilane-treated silicate hybrid sols were confirmed using Fouriertransform infrared (FT-IR) spectroscopy. The viscosity of the sols increased with increasing number of alkoxy functional groups in the organoalkoxysilane and the transmittance of the sol solutions decreased with increasing reaction time. The thermal stability of the hybrid coatings increased with increasing amount of inorganic components. The surface roughness of the coatings depended highly on the homogeneity of the sol solutions. In addition, the contact angle of the hybrid coatings increased as the length of the alkyl chain decreased. Importantly, stabilized hybrid sols and coatings with well-controlled surface and thermal propreties were successfully fabricated by controlling the organoalkoxysilanes and the reaction time.

Five dogs presented with a history of pelvic limb lameness. On physical examination of the stifle joints, five dogs had pain, lameness, patellar luxation, or ligamentous instability. Craniocaudal and mediolateral radiographic projections revealed osteophytes or subchondral cystic lesions on the stifle joints. Based on a previously described Osteoarthrosis (OA) scoring technique, five dogs showed high OA scores. Combination of surgery and implantation of autologous adipose tissue derived mesenchymal stem cells (aAT-MSCs) or percutaneous injection of aAT-MSCs was determined with informed consent. 1 × 106 aAT-MSCs suspended in PBS was injected in the stifle joints. The follow-ups were completed 12 months after surgery. The follow-up information was based on physical examination by veterinarians. The lameness, pain on manipulation, and OA scores improved six or 12 months after implantation of aAT-MSCs. There was a radiographic evidence of decreased osteophytes and subchondral cystic lesions. These results suggest that implantation of aAT-MSCs can be considered an option for management of cases of OA in the stifle joints.

Here we report an unconventional approach for the single-step synthesis of monolithically integrated electronic devices based on multidimensional carbon structures. Integrated arrays of field-effect transistors and sensors composed of carbon nanotube channels and graphitic electrodes and interconnects were formed directly from the synthesis. These fully integrated, all-carbon devices are highly flexible and can be transferred onto both planar and nonplanar substrates, including papers, clothes, and fingernails. Furthermore, the sensor network can be interfaced with inherent life forms in nature for monitoring environmental conditions. Examples of significant applications are the integration of the devices to live plants or insects for real-time, wireless sensing of toxic gases.

Iron sulphate roasting and water leaching were investigated to extract lithium from lepidolite in this study. HSC modelling was used to simulate the process of roasting lepidolite with FeSO 4 ·7H 2 O and CaO. Based on HSC, three-dimensional models were derived to predict the effect of temperature, SO 4 /Li and Ca/F molar ratios on the production of S- and F-containing gases (SO 2 , SO 3 , HF) and Li species (Li 2 SO 4 , LiKSO 4 ) during roasting. It is believed that temperature and SO 2 /SO 3 gases controlled the extraction of lithium from lepidolite during roasting while more soluble Li sulphate species determined the recovery of lithium during leaching. Using optimum parameters selected from HSC, roasting tests were conducted to produce calcines for leaching. Optimum roasting conditions were experimentally determined as 850 °C, 1.5 h, and SO 4 /Li and Ca/F molar ratios of 3:1 and 1:1, respectively. Roasting in a closed environment led to more Li extracted than with an open system. Leaching the calcines obtained from the open and closed systems with a water/calcine mass ratio of 1:1 at room temperature for 1 h yielded leach liquors containing ~ 7.9 g/L Li and ~ 8.7 g/L Li, corresponding to ~ 85% and ~ 93% extractions of Li from lepidolite, respectively.

Silica–titania nanohybrid materials were synthesized using functionalized organosilanes and organically chelated titanium alkoxide in a simple sol–gel process. The synthesized silica–titania nanohybrid materials exhibited good solution processability and homogeneous dispersion without any phase separation regardless of the ratio of the mixture of the two components. The silica–titania nanohybrid materials exhibited good photoinitiator solubility and effective photocurability with a high degree of degree under ultraviolet (UV) exposure. Because of their high photocurability and solution processability, the silica–titania nanohybrid materials were readily converted into silica–titania nanohybrid films and were used for direct photopatterning without requiring the developing process used in the photomask method. In particular, the refractive indices of the silica–titania nanohybrid materials could be decreased by decreasing the content of chelated titanium alkoxide in the materials. Moreover, the silica–titania nanohybrid films exhibited high transmittance in the visible wavelength range, and their surface roughnesses were very smooth, exhibiting values

Nanostructures of single crystallites of spinel LiMn2O4 (LMO) were prepared by the simple pyrolysis of aqueous solution of LiNO3 and Mn(NO3)2 in a confined space such as either droplets or mesopores. When the mixed nitrate solution was spray pyrolyzed at temperatures below 700 °C, 1-μm LMO spheres were obtained consisting of ~20-nm single crystallites randomly packed. Such LMO phase, once obtained, would sustain for further heat-treatment. Next, new spraying solution was prepared by adding the precursor for mesoporous silica (MPS) to the nitrates solution. By spray pyrolyzing such solution, LMO was impregnated inside pores of the MPS being structured. The silica could be removed by subsequent NaOH treatment to leave spherical LMO mesophase. The nitrates was also able to soak into the existing MPS having cylindrical pores and form short isolated LMO chains in the mesopores by the subsequent heating. After the same NaOH treatment, the LMO phase turned into bundles of very ‘long’, and often straight, chains, consisting of 8-nm LMO nanoparticles. This will be elucidated through further study.

Containing 10.2 Mt Li, Salar de Uyuni is known to be the richest resource of Li in the world. A high Mg/Li mass ratio of 21.2:1 of the Uyuni salar brine used in this study is a significant factor hindering the effective lithium recovery. Stabcal modelling was first conducted to study the conditions and chemical speciation of various species involved in the selective precipitation of Mg and Ca oxalate. Along with the addition of oxalic acid, the effect of pH was then studied in order to determine optimal conditions to selectively remove Ca and achieve high Mg yield subsequently. At an Oxalate/Ca molar ratio of 6.82:1 and pH 95% Mg was obtained (precipitate containing mostly Mg oxalate) together with the K and Li losses of up to 35% from the original brine. Washing would remove Li, K contaminants and the co-precipitated sodium sulphate and oxalate . Their absence from the final precipitate was confirmed by XRD analysis. The high purity (99.5% grade) Mg precipitate obtained could be used as a precursor for MgO production.

Key factors controlling the extraction of lithium from a lepidolite concentrate (2.55% Li) using a two-stage process based on roasting with Na2SO4 and water leaching were determined in this study. HSC software was used to predict lepidolite decomposition characteristics and products yielded from roasting. From this simulation roasting was conducted at 850–1000 °C with different sodium sulphate additions (set at sodium sulphate-lithium molar ratios of 1:1 to 3:1) in 0.5–2 h to yield several calcines for leaching. Stabcal modelling was applied to investigate the stability of various Li species formed during water leaching. From the simulation it was identified that LiKSO4, as one of the main Li-containing products formed in the calcine, has a low solubility and therefore controls the release of Li into water during leaching. The low solubility of LiKSO4 at 25 °C indicated by Stabcal was confirmed during leaching at different water–calcine mass ratios from 5:1 to 15:1. Leaching under these conditions only yields liquors containing

A hydrometallurgical process was developed to recover lithium from a brine collected from Salar de Uyuni, Bolivia, which contains saturated levels of Na, Cl and sulphate, low Li (0.7–0.9 g/L Li) and high Mg (15–18 g/L Mg). Unlike other commercial salar brines currently being processed, the high levels of magnesium and sulphate in Uyuni brine would create difficulties during processing if conventional techniques were used. A two-stage precipitation was therefore first adopted in the process using lime to remove Mg and sulphate as Mg(OH) 2 and gypsum (CaSO 4 .2H 2 O). Boron (at 0.8 g/L in the raw brine), a valuable metal yet deleterious impurity in lithium products, could also be mostly recovered from the brine by adsorption at a pH lower than pH11.3 in this first stage. The residual Mg and Ca (including that added from lime) which were subsequently precipitated as Ca–Mg oxalate could be roasted to make dolime (CaO ∙ MgO) for re-use in the first stage of precipitation. Evaporation of the treated brine up to 30 folds would produce 20 g/L Li liquors. The salt produced during evaporation was a mixture of NaCl and KCl, containing acceptable levels of sulphate, Mg, Ca, etc. The final precipitation of lithium at 80–90 °C produced a high purity (99.55%) and well crystalline lithium carbonate.

A study on the behavior of boron extraction by TMPD(2,2,4-trimethyl-1,3-pentanediol) was carried out to find the optimumconditions for the boron extraction from brine. In case of boron extraction from 0.736 g/L boron-containing brine, typical opti-mum extractive conditions would be confirmed to be 0.75 mol/L of extractant concentration at 3.0 pH of brine with 1 of phaseratio and 20 min. of shaking time at 298 K respectively. And 1 mol/L sodium hydroxide of stripping agent was shown above99 % of boron extraction and stripping efficiencies. Also, extraction equilibrium equation were obtained through experimentsas follows : log D = 1.7 log [TMPD] O + constant at pH < 6 Keywords : brine, boron, solvent extraction, diol-type extractant, 2,2,4-trimethyl-1,3-pentanediol 1. 서론 최근 녹색에너지 산업 발전과 함께 급증하는 2차전지용 리튬 수요에 대응하기 위하여 새로운 리튬 자원으로서 고농도 리튬의 염수뿐만 아니라 저농도 리튬 염수로부터 경제적인 고순도 탄산리튬 제조공정 등 다양한 공정기술이 개발 중에 있다 1) . 이러한 리튬 자원의 다양화와 함께 공정의 경제성을 극대화하기 위해서는 리튬 이외에도 염수 중 존재하는 기타 유가원소인 칼슘, 마그네슘, 나트륨, 칼륨, 보론 등에 관한 자원화 기술도 필수적으로 요구되고 있는 실정이다.염수 중 보론은 리튬과 함께 공존하는 수용성 불순이온으로서 2차전지용 리튬 화합물의 규격상 엄격히 규제되고 있는 물질로, 탄산리튬 내 함량이 수 ppm 수준으로 제어되어야 한다. 이러한 보론은 일부 국가에만 부존

Pharmaceutical industry makes extensive use of Raneynickel catalyst for various organic drug intermediates/end products. Spent catalysts contain environmentally critical and economically valuable metals. In the present study, a simple hydrometallurgical process using dilute sulfuric acid leaching was described for the recovery of nickel from spent Raneynickel catalyst. Recovery of nickel varied with acid concentration and time, whereas temperature had negligible effect. Increase of S/L ratio to 30% (w/v) showed marginal effect on nickel (90%) recovery, whereas Al recovery decreased drastically to approximately 20%. Under the optimum conditions of leaching viz: 12 vol.% H(2)SO(4), 30 degrees C, 20% solid to liquid (S/L) ratio and 120 min reaction time, it was possible to recover 98.6% Ni along with 39.2% Al. Leach liquor [pH 0.7] containing 85.0 g/L Ni and 3.25 g/L Al was adjusted to pH 5.4 with 30 wt.% alkali for quantitative aluminum removal. Nickel loss was about 2% during this Al removal step. Nickel from the purified leach liquor was recovered as nickel carbonate by adding required amount of Na(2)CO(3). The purity of NiCO(3) product was found to be 100% with a Ni content of 48.6%. Na(2)SO(4) was recovered as a by-product with a purity of 99%. Complete process is presented.

Nickel oxide particles were prepared by spray pyrolysis of aqueous solution of NiCl2·6H2O. In the reactor the salt droplets were first converted to hollow particles by drying and then they were collapsed by oxidation to reduce their size. Each oxide particle was composed of many small nuclei with voids among them due to extremely low rate of sintering. The particle size decreased with the temperature as the sintering and crystallization proceeded. The size as well as the crystallinity of the particles increased with the initial salt concentration. When the salt droplets were pre- liminarily dried in diffusion dryer before entering the reactor, the collapse of the particles was considerably reduced, resulting in lower hollowness and higher sphericity. Numerical simulation on the drying of the droplets provided insight on the initial stage of spray pyrolysis.

Photocurable inorganic–organic hybrid materials were prepared from colloidal-silica nanoparticles synthesized through the sol–gel process and using acryl resin. The synthesized colloidal-silica nanoparticles had uniform diameters of around 20 nm and were organically modified, using methyl and methacryl functional silanes, for efficient hybridization with acryl resin. The organically modified and stabilized colloidal-silica nanoparticles could be homogeneously hybridized with acryl resin without phase separation. The successfully fabricated hybrid materials exhibit efficient photocurability and simple film formation due to the photopolymerization of the organically modified colloidal-silica nanoparticles and acryl resin upon UV exposure as well as an excellent optical transmission of above 90% in the visible region and an enhanced surface smoothness of around 1 nm RMS roughness. They likewise exhibit improved thermal and mechanical characteristics, much better than those of acryl resin. Lastly and most importantly, these photocurable hybrid materials fabricated through the synergistic combination of colloidal-silica nanoparticles with acryl resin are candidates for optical and electrical applications.

The electrical insulation properties and the tracking and erosion resistances of high-temperature vulcanized silicone rubber were investigated as to the concentration of alumina trihydrate (ATH) therein for the fabrication of silicone rubber with optimum ATH content. Controlling the ATH concentration has been found to be an important factor in the enhancement of the tracking and erosion resistances of silicone rubber. In addition, the silicone rubber showed constant electrical resistivity and dielectric breakdown voltage without any decrease due to the interfacial problems with the addition of ATH to the silicone rubber. Therefore, this fabricated silicone rubber that contains an optimum ATH concentration can be applied to outdoor high-voltage insulators.

We fabricated sub-wavelength periodic structures by thermal nano-imprinting using our original functionally modified inorganic–organic hybrid materials. The fabricated structures exhibited excellent uniformity and surface smoothness over a large imprinted area. In addition, optical transmittance is more than 90% within visible wavelength regions after heat treatment for 2 h at 300 °C. These nano-imprinted periodic structures showed high thermal durability without any structural changes after heating for 2 h at 200 °C, which is superior to commercially available organic imprinting materials. These nano-imprinted sub-wavelength periodic structures using our original inorganic–organic hybrid materials offer great potential for several applications in microphotonic and nanophotonic devices.

The combination of bioceramics with biopolymers are playing major role in the construction of artificial bone. Hydroxyapatite (HA) has been extensively studied as a material in bone repair and replacement in last two decades. In the present study, we have prepared the hydroxyapatite-fucoidan (HA-Fucoidan) nanocomposites by in situ chemical method and biologically characterized them for bone graft substitute. Biological results inferred that mineralization effect of HA-F nanocomposites shows significant enhancement compared to HA in adipose derived stem cell (ADSC). It may be due to the addition of fucoidan in the nanocomposites. The important gene expression such as osteocalcin, osteopontin, collagen and runx-2 were checked using ADSC with HA and HA-fucoidan nanocomposites and the results show that the enhancements were found at 7th day. Furthermore, we have performed in vivo study of HA-fucoidan nanocomposites with rabbit model and a slight amount of bone formation was observed in HA-fucoidan nanocomposites. Herewith, we suggest that HA-fucoidan nanocomposites will be good biomaterials for bone repair/replacement in future.

Solventless silica-acryl hybrid materials composed of organically modified silica nanoparticles and acryl monomers were fabricated using a simple sol-gel process and solvent evaporation. The homogeneously dispersed silica-acryl hybrid materials can be formed into films through a simple solution-coating process and UV curing. The silica-acryl hybrid materials exhibited good photocurability with -90% conversion upon UV exposure and a high transmittance of above 95% in the visible wavelength region regardless of the silica nanoparticle content. In particular, the silica-acryl hybrid materials exhibited increased mechanical hardness and thermal stability directly proportional to the content of silica nanoparticles and exhibited a good surface roughness of -1 nm. Therefore, these silica-acryl hybrid materials are good candidates for coating applications in electronic, electro-optic, and energy devices.

Photosensitivity, as evident in permanent changes in refractive index and volume upon light exposure, is observed in a germanium-doped methacrylate hybrid material (hybrimer) and found to depend on the wavelength of the UV light. Exposure to short-wavelength UV illumination (220–260 nm) results in very high photosensitivity with changes in refractive index (Δn ≈ 0.0164) and film thickness (Δt ≈ –40 %) that are mainly a result of photopolymerization and Ge-related densification. In contrast, the hybrimer is hardly photosensitive to light in the long UV-wavelength range (350–390 nm). Direct photopatterning of a single circle on the hybrimer film creates a concave lens-like topography upon illumination with UV light of short wavelength and a convex lens-like one upon illumination with UV light of long wavelength.

Nickel oxide particles were prepared by spray pyrolysis of aqueous solutions of NiSO4·6H2O and Ni(NO3)2·6H2O. In spray pyrolysis reactor hollow salt particles initially formed were collapsed by decomposition to reduce their size. For NiSO4·6H2O less hollowness of the primitive particles and its higher decomposition temperature made the oxide particles highly spherical with very smooth surface. On the other hand the particles prepared from Ni(NO3)2·6H2O were so hollow and fragile with rough surface since they were formed on the liquid pool of the salt melt. The particle size decreased with the furnace set temperature while increased with the initial salt concentration. Single oxide particle was composed of many small nuclei without sintering whose size varied with the rate of decomposition. The crystallinity of the particles increased with both temperature and the initial salt concentration. Preliminary drying in diffusion dryer fixed the size of the oxide particles from NiSO4·6H2O at that of the primitive particles, independent of the temperature. However, by the preliminary drying the particles from Ni(NO3)2·6H2O became more hollow and fragile, whose sizes decreased with the temperature.

Nickel particles were prepared by spray pyrolysis of aqueous solutions of NiCl2·6H2O with reducing gas. Wet pyrolysis lowered the onset and the finishing temperatures of the individual chemical transformations by at least 100°C to contribute high conversion to nickel and its completion of sintering. Densification by increasing the furnace set temperature outweighed the adverse effects of the dry sintering and short residence time of the precursor particles. The initial salt concentration increased the size of the nickel particles with their densification, resulting from the enhanced rate of nickel nucleation.

Fluorinated inorganic-organic hybrid materials (HYBRIMER) were successfully prepared from fluoroalkylsilanes (FASs) containing fluoro-alkyl functions and methacryloxypropyltrimethoxysilane (MPTMS) through a sol-gel process. The influence of concentration and fluoro-alkyl chain lengths of FASs on the physical characteristics of the fluorinated HYBRIMER films was examined. Larger fluorine contents lowered the refractive index within a range, which was closely dependent on the fluoro-alkyl chain lengths of FASs. Thermo-optic coefficients (TOC) were negative values, and the values grew with increasing fluorine contents and fluoro-alkyl chain lengths. Also, the thermal stability is enhanced by addition of fluorine in the HYBRIMER.

Organically modified germanosilicate (ORMOGSIL) glasses prepared by a sol-gel method showed a large refractive index change on ultraviolet exposure. The large photoinduced refractive index change in the ORMOGSIL glasses is mainly due to the structural densification caused by ultraviolet irradiation. The shifts in frequency of the Raman bands measured at room temperature reveal structural densification by reduction of the average intertetrahedral bonding angle θ in the ORMOGSIL glasses. Surface relief patterns by photoinduced densification were directly inscribed on the ORMOGSIL glasses.

TiO2-SiO2 composite nanoparticles with different intraparticle structures were prepared by varying modes of reactant mixing in equimolar vapor-phase hydrolysis of TTIP and TEOS. They included the structures of core-shell, either titania core surrounded by silica shell (abbreviated by T-S) or vice versa (S-T), and of mixed type, one oxide dispersed in the other (T/S). Design of mixing junction between TTIP and H2O was very critical due to high hydrolysis rate of TTIP. That of TEOS was, however, so low that atomic silicon percentage of the particles was always less than 50%. The percentage increased with the temperature of reactor and the free surface of titania. Thus, due to the availability of the surface, the highest and the smallest silicon contents were obtained in the T/S and the S-T particles, respectively. In case of the former, as the temperature increased to 950°C, the silicon content reached 50% and, moreover, silica-rich particles appeared originating from homogeneous nucleation of the component. Average size of primary particles, irrespective of the structures, decreased with the content of silicon. In addition to the silicon effect, the gap in the sizes of the T-S and the S-T particles was further promoted, ultimately by the difference in the hydrolysis rates of the two alkoxides. The difference also caused radial gradient of composition even inside each primary T/S particle. Structural identity of shell component was affected by the existence of core component for both the T-S and the S-T particles.

Various TiO2/SiO2 composite nanoparticles were prepared by vapor phase hydrolysis of Titanium Tetraisopropoxide (TTIP) and Tetraethylorthosilicate (TEOS) in a tubular reactor heated by electrical furnace by changing the methods of reactant mixing, the molar ratio of the precursors and the set temperature of the furnace. These variables affected the average size and the bulk composition of the particles as well as their morphological and crystalline structures. The morphological structures of the particles were reconfirmed as T-S, S-T and T/S as in the previous study. Various correlations were obtained between the molar ratio of the precursors, and the size, the composition and the TiO2 main peak intensity of the particles as a parameter of the mode of reactant mixing. In general, it was found that high content of silicon constituent showed translucent envelopes surrounding primary particles, which increased the dispersion diameter of the particles, reduced the thermal stability, retarded the anatase-to-rutile transformation and the initial photocatalytic degradation of phenol in an aqueous solution.

Hybrid materials composed of organically modified silica nanoparticles and oligosiloxanes exhibited homogeneous dispersion without any phase separation or aggregation and good solution processability. These hybrid materials exhibited good solubility of photoinitiator and high transmittance of above 90% in visible wavelength ranges. In particular, the materials showed high photocurability, with degrees of conversion under UV exposure above 90%. With high photosensitivity, the hybrid materials were used for direct photopatterning without the developing process used in the photomask method. The various optical surface structures on a micrometer scale were easily fabricated in the hybrid films upon UV exposure, and the samples exhibited good root-mean-square (RMS) roughness of around 1 nm. (C)2012 Optical Society of America