Temperature Synthesis Research Articles

Synthesis of temperature and salt resistance silicon dots for effective enhanced oil recovery in tight reservoir

The intensive development of tight reservoirs has positioned them as a strategic alternative to conventional oil and gas resources. Existing enhanced oil recovery (EOR) methods struggle to effectively exploring reservoir oil, resulting in low recovery rates. Novel and effective means of developing tight reservoirs are urgently needed. Nanomaterials have shown promising applications in improving water flooding efficiency, with in-depth research into mechanisms that lower injection pressure and increase water injection volumes. However, the extent of improvement remains limited. In this study, a silicon quantum dots (Si-QDs) material was synthesized via a hydrothermal synthesis method and used to prepare a nanofluid for the efficient recovery of tight reservoir. The Si-QDs, with an approximate diameter of 3 nm and a spherical structure, were surface functionalized with benzenesulfonic acid groups to enhance the performance. The developed nanofluid demonstrated stability without aggregation at 120 °C and a salinity of 60000 mg/L. Core flooding experiments have demonstrated the attractive EOR capabilities of Si-QDs, shedding light of the EOR mechanisms. Si-QDs effectively improve the wettability of rocks, enhancing the sweeping coefficient of injected fluids and expanding sweeping area. Within this sweeping region, Si-QDs efficiently stripping adsorbed oil from the matrix, thus increasing sweeping efficiency. Furthermore, Si-QDs could modify the state of pore-confined crude oil, breaking it down into smaller particles that are easier to displacement in subsequent stages. Si-QDs exhibit compelling EOR potential, positioning them as a promising approach for effectively developing tight oil reservoirs.

Исследование продуктов синтеза в механоактивированных смесях титанидов меди с углеродом

Metal matrix composites reinforced with dispersed carbide particles have an optimal combination of strength and wear resistance. The composites are used as structural materials, wear-resistant materials and coatings as well as functional materials. Copper matrix composites for electrical purposes are strengthened with particles of refractory compounds (carbides, borides, silicides). They are used to manufacture breaking electrical contacts which have increased resistance to erosion under the electric arc exposure. The highest arc erosion resistance is achieved by composites with a structure, in which submicron particles of refractory compounds are homogeneously distributed in the copper matrix. Powder technologies are used to obtain the copper matrix composites. A large number of publications concerns with the production of copper matrix composites strengthened by dispersed particles of titanium diboride. The composite powder was obtained by self-propagating high- temperature synthesis (SHS) occurring through mechanically activated mixtures of titanium, copper and carbon. The synthesis products were compacted by spark plasma sintering (SPS). In the present work, the microstructure, elemental and phase composition of the products of the synthesis reaction occurring through mechanically activated reactant powder mixtures of copper titanides with carbon (soot) subjected to additional heat treatment were studied using the methods of X-ray diffraction, optical and scanning electron microscopy. Copper matrix composites strengthened by carbide particles were obtained by copper reduction from intermetallic compounds (copper titanides) via reaction: TimCun+ C → TiC + Cu. The use of the copper titanides instead of titanium and copper powders eliminates the blocking of surface titanium-carbon reaction by copper during the mechanical activation of titanium-copper-carbon powder mixtures. This ensures a more complete conversion of titanium carbide in the synthesis reaction. It is established that the dispersion of the carbide phase in the structure of the synthesized ‘titanium carbide-copper binder’ composite depends on the elemental ratio of titanium and copper in the reaction mixtures. With an equiatomic content of titanium and copper the synthesis results in a matrix-type composite, in the structure of which submicron (less than 300 nm) carbide inclusions are homogeneously distributed throughout the copper binder. Unreacted copper and titanium in the titanide powders do not prevent the attainment of target phase composition of the synthesis products that include only titanium carbide and copper.

Sediment yield in the Lower Jinsha River Basin, China: Controlling factors and spatiotemporal patterns

The spatiotemporal pattern of sediment yield is critical for the management of mega cascade reservoirs in the Lower Jinsha River Basin (LJRB), despite that the scarcity of information has limited our knowledge. This study used a stepwise statistical approach to determine the synergistic factors controlling sediment yield, and relevant models were established to provide predictions for ungauged areas in the mountainous basin. Existing observations for 18 catchments (102–104 km2) displayed an imbalanced distribution pattern of specific sediment yield (SSY = 83–1269 t km−2 a−1) in the LJRB, while 6 combinations of local characteristics were found to properly explain the variability (63–92%). The synthesis of temperature, slope proportion, and drainage area exhibited the most explanatory power, where the temperature factor appeared to exert the dominant effect on SSY. This study has effectively simplified the redundant factor dataset by multivariate and partial correlation methods, lowering the bar for modeling analysis. Predictions have been made to present full distribution patterns of sediment yield in the LJRB, characterized by high yields in the middle (cold and steep) and low yields at both ends (warm and flat). This enabled us to detect considerable ungauged areas with abundant sediment yields between cascade reservoirs Xiluodu and Baihetan. Regionalized SSY has decreased by 10–71% over the past 50 years, associating with the superior vegetation condition in response to rising temperatures. Moreover, 2050 projections via two extreme Shared Socioeconomic Pathways (SSP119 and SSP585) suggested that regionalized SSY would continue to decrease by 32–51% on average. The current assessment and future prediction of sediment yield in the LJRB should be useful for engineering purposes, and the proposed modeling approach can provide reference for upper lands and mountainous basins.

Investigation of use in 5-FU release: Synthesis of temperature and pH responsive P(NVCL-co-VIm)/PVP hydrogels

Investigation of use in 5-FU release: Synthesis of temperature and pH responsive P(NVCL-co-VIm)/PVP hydrogels

Synthesis of temperature- and humidity-induced dual stimulation film PU-PNIPAm n and its independent film formation as a smart window application.

Dynamic windows, which switch between transparent and opaque states as the temperature changes, can be applied in buildings to reduce building energy consumption. Poly(N-isopropylacrylamide) (PNIPAm) is the most studied thermochromic hydrogel for climate-resilient smart window applications. In addition to its poor mechanical properties and low reaction rate, the PNIPAm hydrogel must be sandwiched between two pieces of glass to form an interlayer in practical applications. Here, durable PU-PNIPAm n copolymers for smart windows were synthesized by reacting the synthesized poly-NIPAm diols with isocyanate (-NCO) monomer, which greatly improved the mechanical properties of the hydrogel and it was able to form a film alone. These temperature-sensitive films can switch between transparent (>80% transmittance) and opaque (<5% transmittance) states in less than 10 minutes, with no degradation in optical contrast, switching speed, or uniformity after at least 100 switching cycles.

Synthesis of temperature and pH responsive lignin-grafted sulfobetaine for efficiently recycling cellulase

Recycling cellulase can reduce the cost of lignocellulosic enzymatic hydrolysis. Here, a lignin-grafted sulfobetaine (LSB) was first synthesized by grafting sulfobetaine (SB) on enzymatic hydrolysis lignin (EHL). LSB had a sensitive response of pH and temperature. LSB dissolved under the conditions of lignocellulosic enzymatic hydrolysis (pH 5.0, 50 °C). After hydrolysis, LSB co-precipitated with cellulase when lowering pH of the hydrolysate to 4.0 and cooling to 25 °C. When 3.0 g/L LSB-100 was added to the hydrolysis system of corncob residue (CCR), 70 % of amount of cellulase was saved. LSB had a remarkable response and stronger cellulase recovery capacity. This was attributed that carboxylate radical in LSB was protonated, and positive and negative ions of SB associated to form salt at 25 °C. This work provides a new idea for reducing the cost for preparing fermentable sugars from lignocellulose, and increasing the added value of EHL.

Cobalt-Activated Transfer-Free Synthesis of the Graphene on Si(100) by Anode Layer Ion Source

In this research, the graphene was grown directly on the Si(100) surface at 600 °C temperature using an anode layer ion source. The sacrificial catalytic cobalt interlayer assisted hydrocarbon ion beam synthesis was applied. Overall, two synthesis process modifications with a single-step graphene growth at elevated temperature and two-step synthesis, including graphite-like carbon growth on a catalytic Co film and subsequent annealing at elevated temperature, were applied. The growth of the graphene was confirmed by Raman scattering spectroscopy and X-ray photoelectron spectroscopy. The atomic force microscopy and scanning electron microscopy were used to study samples’ surface morphology. The temperature, hydrocarbon ion beam energy, and catalytic Co film thickness effects on the structure and thickness of the graphene were investigated. The graphene growth on Si(100) by two-step synthesis was beneficial due to the continuous and homogeneous graphene film formation. The observed results were explained by peculiarities of the thermally, ion beam, and catalytic metal activated hydrocarbon species dissociation. The changes of the cobalt grain size, Co film roughness, and dewetting were taken into account.

Manufacturing and Processing of Carbon Nanotubes for H2 Storage

In pursuit of manufacturing of carbon nanotubes (CNTs) in good yield at lower temperatures, a mixture of d-block elements such as Iron, Nickel, and Cobalt was expected to be advantageous because of the high yield and low temperature (at 220 - 250° C) synthesis. The physical state and aggregation of these catalyst particles in the reaction medium have been found to play an interesting role in obtaining CNTs at better yield. Carbon nanotubes have been successfully produced by an uncomplicated two-step solvothermal method between sodium and dichlorobenzene via Ni/Fe/Co as catalyst precursor. The dependence of yield of CNTs on the catalyst system was determined via different ratios of catalysts and at various other experimental conditions such as different heating temperatures, different durations of heating. The X-ray powder diffraction study has indicated the graphite kind of the products. Microscopic characterizations (SEM and TEM) implied us the diameters of carbon nanotubes are 10-14 nm. Raman spectroscopy shows the presence of graphitized carbon in carbon nanotubes. Significant influence by the heating temperature and heating duration has been observed on the product yield.

Synthesis and characterization of temperature stable low-loss (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 (0 ≤ x ≤ 0.1) ceramics for microwave applications

In the present work, we prepared (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 (0 ≤ x ≤ 0.1) solid-solutions via traditional solid-state reaction process and investigated their structural, optical, electrical, dielectric, and shielding properties. We report that these (1−x)Mg(Ti0.95Sn0.05)O3–(x)BaTiO3 compounds experienced structural phase transitions, wherein the tetragonal-structured BaTiO3 (space group P4mm) got transformed to monoclinic-structured Ba4Ti11O26 (space group C12/m1), and triclinic-structured Ba2Ti9O20 (space group P1). Interestingly, the Mg(Ti0.95Sn0.05)O3 showed no structural phase transition and was crystallized in its purest form without secondary phase formation. Additionally, the prepared compositions showed ten Raman active modes, and the relative density of all the samples exceeded 93.5%. The optical bandgap (Egap) values and DC conductivities of the samples were in the range of 3.82 eV–3.92 eV and 9.03 × 10−10 Sm−1–2.55 × 10−9 Sm−1, respectively. The composition 0.925 Mg(Ti0.95Sn0.05)O3–0.075BaTiO3 exhibited the best dielectric properties having relative permittivity (ɛr) of 19.69, loss tangent (tan δ) of 5.1 × 10−3, and temperature coefficient of resonant frequency (τf) of -8.5 ppm/°C at 1 MHz. In the Ku-band (12.4–18 GHz), this composition showed ɛr in the range of 14.62–15.49 and tan δ in the range of 2.85 × 10−2–5.89 × 10−2. An investigation of shielding properties in the Ku-band revealed that the prepared samples delivered average shielding effectiveness in the range of 5.98–6.65 dB. The prepared materials are proposed for microwave applications.

Low temperature and pressureless synthesis of MgAlON: qualitative analysis and formation evolution

Abstract By calculating the Gibbs free energy of a magnesium aluminium oxynitride (MgAlON) system, pure MgAlON was obtained by pressureless sintering at 1 570 °C in a nitrogen atmosphere using Al, Al2O3, and MgO as raw materials. The formation mechanism of MgAlON and phase evolution of the Al-Al2O3-MgO-N2 system were investigated. The aluminium was melted at approximately 660 °C and formed AlN in the range 740- 1 250 °C. The reaction of AlN, Al2O3, and MgO started to form a primary crystalline MgAlON phase at 950 °C, and as the temperature increased, the minerals continuously dissolved in the primary crystalline phase.

Chemical modification of the polymer of intrinsic microporosity PIM-1 for enhanced hydrogen storage

A detailed investigation has been carried out of the pre-polymerisation modification of the polymer of intrinsic microporosity PIM-1 by the addition of two methyl (Me) groups to its spirobisindane unit to create a new chemically modified PIM-1 analogue, termed MePIM. Our work explores the effects of this modification on the porosity of PIM-1 and hence on its gas sorption properties. MePIM was successfully synthesised using either low (338 K) or high (423 K) temperature syntheses. It was observed that introduction of methyl groups to the spirobisindane part of PIM-1 generates additional microporous spaces, which significantly increases both surface area and hydrogen storage capacity. The BET surface area (N2 at 77 K) was increased by ~ 12.5%, resulting in a ~ 25% increase of hydrogen adsorption after modification. MePIM also maintains the advantages of good processability and thermal stability. This work provides new insights on a facile polymer modification that enables enhanced gas sorption properties.

Temperature effect on the PpIX production during the use of topical precursors.

Decreasing incubation time, as well as enhanced PpIX production, are present challenges for topical photodynamic therapy (PDT). There are reports concerning the existence of a strong relationship between site temperature and porphyrin synthesis in biological tissue, that suggest temperature increase in the tissue can improve the formation of PpIX. The main objective of this study is to determine whether the temperature change of the tissue favors the production of PpIX. Creams containing aminolevulinic acid (ALA) and methyl aminolevulinate (MAL) were topically administered for 30 min on healthy skin of rats' back and the formation of PpIX was evaluated for 180 min. The animals were divided into 5 groups: cooling tissue to 20 °C or heating tissue to 40 °C (either before or after incubation of the cream) and control group (unchanged temperature). The tissue temperature was evaluated by thermography. The influence of temperature was evaluated both concerning cream penetration and the production of PpIX. It was found that both ALA and MAL led to an increase of about 20% PpIX production when the tissue was warmed before incubation of the cream, suggesting that the penetration improved. When the thermal change was promoted after incubation of the cream, the production of PpIX decreased both by heating and cooling, probably related to enzyme modification. The results found in this study suggest that the increase of tissue temperature before the cream incubation can improve the clinical protocols of topical PDT using ALA or MAL, improving the efficiency of the procedure by increasing the production of PpIX and allowing the decrease of the incubation period.

Synthesis of temperature and light sensitive mixed polymer brushes via combination of surface-initiated PET–ATRP and interface-mediated RAFT polymerization for cell sheet application

In this study, a series of temperature and light sensitive mixed polymer brushes consisting of poly(2-(2-methoxyethoxy) ethyl methacrylate) [poly(MEO2MA)] and poly(N-[4-[(4-nitrophenyl) azo] phenyl] acrylamide) [poly(NPAPAA)] units were grown on silicon wafer via the combination of surface-initiated photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP) and interface-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. This process was realized in five consecutive steps: (i) coupling of previously synthesized (3-aminopropyl) triethoxysilane-2-bromoisobutyryl bromide (APTES-BIBB) and (3-aminopropyl) triethoxysilane-t-butoxycarbonyl (APTES-t-BOC) mixtures to the Si-OH surface under self-assembly monolayer conditions (ii) synthesis of poly(MEO2MA) units via surface-initiated PET-ATRP (iii) replacement of terminal-Br atoms at poly(MEO2MA) units with biocompatible maleimide molecules (iv) removal of the t-BOC group from APTES-t-BOC and bonding of the RAFT agent to the APTES, and (v) synthesis of poly(NPAPAA) units via the interface-mediated RAFT polymerization. The surface compositions of APTES-BIBB and APTES-t-BOC molecules were determined by the water contact angle data analyzed with the Israelachvili-Gee model and by the X-ray photoelectron spectroscopy measurements. The grafting density (σ, chains nm−2) and the average distance between grafting points (D, nm) of the mixed polymer brushes are about 0.56 chains nm−2 and 1.52 nm, respectively, indicating high grafting density. The lower critical solution temperatures (LCSTs), trans-cis and cis-trans transition times were in the range of 24.6–29.2 °C, 10–25 min and 8–20 min, respectively, depending on the surface composition of the polymer brushes. Cell culture studies revealed successful cell detachment either via the temperature reduction or UV irradiation methods. The cell recovery ratios were recorded as 99.05 ± 0.45% and 83.95% ± 0.58%, respectively. These experimental findings provided basic information at the molecular level in the preparation of temperature and light- sensitive bioactive surfaces for cell sheet preparation and detachment state.

Synthesis of Temperature and Light Sensitive Copolymers with Controlled Aggregation during Phase Transitions

AbstractTwo thermosensitive copolymers of acrylates (PMP/PEP) and a thermo/light sensitive copolymer of acrylate with acrylamide (PMABz) are synthesized via a ring‐opening reaction and subsequent radical polymerization using a facile one‐pot method. The lower critical solution temperature (LCST) of PMP and PEP shows a dependence on the content of the structural unit and can be easily tuned to 18–35 °C by mercaptoethanol‐mediated control of the molecular weight. The isomerization of PMABz can be reversibly induced by alternating irradiation at 365 nm to produce the cis form and at 254 nm to produce the trans form. The LCST of cis‐PMABz (40.3 °C) is significantly higher than that of trans‐PMABz (37.8 °C) because of its higher hydrophilicity. Furthermore, the particle size of aggregated PMABz can be controlled from 665 nm (for the cis form) to 996 nm (for the trans form) during the heating run. After quenching the PMABz solution, PMABz particles have repeating patterns, such as leaf veins or hollow containers, indicating their potential applicability.

Synthesis and effect of temperature on morphological and photoluminescence properties of TiO2 nanoparticles

Sol–gel preparation of pure anatase TiO2 calcined at different temperatures has rarely been reported. The current study reports the relative investigation for the elaboration of TiO2 nanoparticles by sol–gel technique. SEM has been considered for the TiO2 samples before as well as for the following calcinations. The XRD pattern illustrated the purity of TiO2 particle materials and the average crystal size of our sample was calculated. The consequences have been discussed in the light of difference of morphological structures of diverse samples of nanomaterials. The optical reflectance of TiO2 nanoparticles demonstrated that all materials have an elevated reflectance (∼ 93%) in the 380–790 nm spectrum. Together for this, the Eg of the elaborated TiO2 samples has been considered from the spectrophotometric examination, which is quite considerable with the reported consequences. The photoluminescence (PL) spectra show that the sample has yellow strong emission.

High Temperature and High Pressure Synthesis and Magnetic Properties of Arsenic-Based Filled Skutterudite Compounds

We have succeeded in synthesizing new arsenic-based filled skutterudite compounds CaFe4As12and BaOs4As12under high pressure. These compounds have lattice constants of 8.3288 and 8.5809 Å, respectively. The magnetic properties of CaFe4As12and BaOs4As12have been studied by means of electrical resistivity, magnetic susceptibility and magnetization measurements. The electrical resistivity and magnetic measurements indicate that CaFe4As12is a nearly ferromagnetic metal with spin fluctuations of Fe 3delectrons and BaOs4As12is a new superconductor with a transition temperature around 3 K.

Synthesis of NENU metal-organic framework-graphene oxide nanocomposites and their pollutant removal ability from water using ultrasound

The cleaner production of metal-organic framework nanocomposite includes room/low temperature synthesis and the use of harmless solvents. In this paper, metal-organic framework (NENU: Northeast Normal University) - graphene oxide (GO) nanocomposites (NENU/GO) with different amounts of GO (0.005, 0.01, 0.015, 0.02 and 0.03 g denoted as NENU/0.005GO, NENU/0.01GO, NENU/0.015GO, NENU/0.02GO and NENU/0.03GO, respectively) were synthesized at room temperature using ethanol as a harmless solvent. The pollutant (dye) removal ability of the materials from water was studied in details. The GO nanosheet was prepared from graphite. The synthesized nanomaterials were characterized using Brunauer–Emmett–Teller, X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and zeta potential. Dye removal at 5, 10 and 20 mg/L of dye concentration was 87, 84 and 59%, respectively. The pollutant adsorption capacity of the NENU, NENU/0.005GO, NENU/0.01GO, NENU/0.015GO, NENU/0.02GO and NENU/0.03GO was 125, 130, 151, 170, 183 and 243 mg/g, respectively. The pollutant uptake data confirmed the Freundlich isotherm and pseudo-second order kinetics.

Preparation and catalytic study of novel highly porous metal-carbon nanocomposites based on bimetallic Co-Ru nanoparticles

Novel method involving simultaneous formation of highly-porous carbon support and bimetallic Co-Ru nanoparticles was proposed. Joint solution of polyacrylonitrile and metal compounds in dimethylformamide was employed as a precursor of metal-carbon nanocomposites. Applying of infrared heating on the precursor allowed to reduce fabrication time of the nanocomposites significantly. The evolution of Co-Ru solid solution depended on synthesis temperature was studied. The specific surface area of metal-carbon nanocomposites dependence on temperature synthesis was shown as well. It was found that IR annealing of the precursor at 700-800 °C led to carbon matrix formation with specific surface area of about 1300 m2/g. The carbon-supported bimetallic Co-Ru nanoparticles obtained at 800 °C were tested as catalysts in hydrogen production via ethanol steam reforming. The high yield of hydrogen was recorded, whereas by-product yield was relatively low.

Synthesis of temperature, pH, light and dual-redox quintuple-stimuli-responsive shell-crosslinked polymeric nanoparticles for controlled release

Herein, we prepared a novel quintuple-stimuli-responsive shell-crosslinked (SCL) nanocontainer in respond to temperature, pH, light, and oxidation or reduction species. The well-defined amphiphilic diblock copolymer poly(2-methacryloyloxyethyl ferrocenecarboxylate)-(5-propargylether-2-nitrobenzyl bromoisobutyrate)-poly(dimethylaminoethyl methacrylate) (PMAEFc-ONB-PDMAEMA) was synthesized via atom transfer radical polymerization (ATRP) and click chemistry. The diblock copolymer self-assembled into spherical micelles with a uniform size in aqueous media as non-crosslinked (NCL) micelles, and then the micelles were crosslinked by N,N′-bis(bromoacetyl) cystamine (BBAC) through quaternization reaction between the nitrogen of DMAEMA and the bromine of BBAC to receive the SCL micelles which shrunk at higher temperature, swelled at acidic pH or a low concentration of hydrogen peroxide (H2O2), decrosslinked by a small amount of DL-dithiothreitol (DTT), and were disrupted with DTT and UV light. The multi-stimuli-sensitive properties of the SCL micelles were characterized in detail by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence spectra, and UV–Vis spectra. Owing to the protective effect of the crosslinked network, light response behaviors of the NCL and SCL micelles were different. In contrast to the single stimulus, the combined stimuli could trigger and regulate the release of hydrophobic drug model more effectively and precisely from the SCL micelles. The obtained multi-stimuli-responsive nanocontainers may lead to a new generation of controlled release in the fields of nanotechnology and biotechnology.

Synthesis and characterizations of ultra-low sintering temperature BaTiO3/BaO–ZnO–Bi2O3–B2O3 glass ceramic composite

Novel ultra-low temperature co-fired ceramic composites consisting of BaTiO3 and BaO–ZnO–Bi2O3–B2O3 (BZBB) glass were successfully produced under 500 °C, and their sintering behavior, phase composition, microstructure and dielectric properties as functions of sintering temperature were investigated. The XRD and SEM results showed that there was no reaction between the glass and the ceramic but the Bi24B2O39 was formed in all samples during sintering process. This indicates that the BZBB glass not only acts as sintering aids but also involves in crystal phase formation. The composites with 60–90 wt% of BZBB glass frit could be densified at a sintering temperature of 450 °C for 30 min, and exhibited widely adjustable dielectric constant (35–133) and acceptable dielectric loss (<0.012). In addition, the composites showed good compatibility with Ag electrode, which suggests their suitability for various dielectric applications with ultra-low sintering temperature.