Temperature-sensitive Properties Research Articles

Effect of energy transfer and local crystal field perturbation on the thermometric sensitivity of Ga-Tb-Eu ternary emission system

A series of optical thermometers based on Eu 3+ /Tb 3+ doped Y 3 Ga 5 O 12 with self-excited GaO 6 group phosphors were designed through controllable energy transfer and local crystal field perturbation simulated using the density-functional theory approach and related structures. Color-tunable properties of the phosphors could be achieved through controllable energy transfer. In addition, the thermometers exhibited superb temperature sensitive properties. Over the entire temperature range (298.15–598.15 K), maximum values of the absolute sensitivity and relative sensitivity are 0.028 K −1 and 7.03 %K −1 , respectively. Meanwhile, the thermometer has outstanding resolution (ΔT = 0.0043 K) and repeatability (98.37%).

Structure, up-conversion luminescence and optical temperature sensitive properties of glass ceramics containing Ca5(PO4)3F with double luminescence centers

In this study, CaF 2 –ZnO–P 2 O 5 –CaO–SiO 2 system glass ceramics containing Ca 5 (PO 4 ) 3 F nanocrystals were prepared via melting and crystallization, and their structure, up-conversion luminescence properties and energy transfer were investigated. Owing to the different temperature dependences of the three emitting bands at 523, 547 and 659 nm, dual-mode temperature measurement can be realized according to the employed fluorescence intensity ratio technology. Using thermal-coupled energy levels, the maximum relative sensitivity ( S r-max ) and absolute sensitivity ( S a-max ) were found to be 1.71% K -1 and 0.69% K -1 , respectively. Moreover, the maximum relative sensitivity (S r-max ) and absolute sensitivity (Sa-max) were found to be 2.19% K -1 and 0.11% K -1 , respectively, based on the nonthermal coupled energy levels. This shows that fluoroapatite transparent glass ceramics have latent application prospects in the optical temperature measurement field.

Fluorinated carbon dots/carboxyl methyl cellulose sodium composite with a temperature-sensitive fluorescence/phosphorescence applicable for anti-counterfeiting marking

Carbon dots (CDs) have attracted extensive attention due to their excellent optical properties, especially in the tunable photoluminescence (PL) (including fluorescence, delayed fluorescence and phosphorescence) and high photostability. However, the thermal stimuli-responsive PL from CDs based materials is still rare reported so far. In this work, we report a facile, large-scale synthesis of a polymer nanocomposite containing fluorinated carbon dots (FCDs) by using a commercial, water-soluble polymer carboxyl methyl cellulose sodium (CMCNa) as a stabilizing matrix. The as-synthesized FCDs-CMCNa shows both solid-state fluorescence and room temperature phosphorescence (RTP). More interestingly, with temperature decreasing from 300 to 90 K, the FCDs-CMCNa presents a peculiar temperature-sensitive optical property that its fluorescence/phosphorescence intensity both increase with temperature decreasing to a turning point of 150 K and then decline gradually as temperature decreasing to 90 K. This peculiar temperature-sensitive optical property of FCDs-CMCNa can be applied in advanced anti-counterfeiting, information encryption and thermo-sensitive sensors.

Structural, spectroscopic and temperature characterizations of Dy3+-doped CsPbBr3 quantum dots in borogermanate glass-ceramics

Dy 3+ -doped borogermanate glass-ceramics with CsPbBr 3 quantum dots (QDs) were synthesized by the high-temperature melting and heat treatment methods. The structural, morphology, and luminescence temperature-sensitive properties of QDs in glass hosts were investigated using XRD, the high-resolution transmission electron microscopy (HR TEM), and temperature-dependent photoluminescence (PL) emission spectra, respectively. Strong green emission from CsPbBr 3 QDs was observed. The optimal concentration of Dy 3+ ions in borogermanate glasses was also determined. The activation energy (E a ) is estimated as 337.7 meV from the fitting curve of integrated PL emission intensity of CsPbBr 3 versus the reciprocal temperature. The relative sensitivity maximum value of the 0.4 mol% Dy 3+ -doped CsPbBr 3 QDs (CDy0.4) glasses reaches 2.39% K −1 at 298 K. The results indicate that CDy0.4 borogermanate glass-ceramics could be potentially used for high-sensitivity optical temperature sensing applications. • Dy 3+ -doped CsPbBr 3 quantum dots in borogermanate glasses have been fabricated. • The optical properties and microtopography of Dy 3+ -doped CsPbBr 3 QDs glasses is investigated. • The maximum relative sensitivity of 0.4 mol% Dy 3+ -doped CsPbBr 3 QDs glasses reaches 2.39% K −1 at 298 K.

Improving LCC Series-Based Wireless Power Transfer System Output Power at High Temperature

Adding a core to a coupling coil can improve transmission efficiency. However, the added core causes the self-inductance of the coupling coil to increase at a high temperature due to the temperature-sensitive property of the core material’s permeability. The self-inductance increases, causing the resonance frequency to shift down, thereby decreasing the output power. The 3 dB bandwidth of the system can learn of the correspondence between the output power and the resonance frequency. In order to make sure that the output power does not excessively decrease at a high temperature, this study employs a simulation for the LCC-S-based wireless power transfer system. Adding a minor resistance to shift down the lower cutoff frequency ensures that the resonance frequency yielded by the temperature rise can be higher than the lower cutoff frequency, making the output power higher than half of the maximum. Then, an adjustment on the compensation capacitances on the resonant circuit elevates the output power more. The outcomes are consistent with the prediction. Adding the core to the coupling coil improves transmission efficiency; increasing the bandwidth of the system excessively decreases the output power decline at a high temperature for the temperature-sensitive core material permeability.

Laser Power Determination Using Light-to-Heat Conversion Rate of Nanoplasmonic Substrates for Neural Stimulation.

Since neurons have temperature sensitive properties, gold nanorod (GNR)-mediated photothermal stimulation has been developed as a neuromodulation application. As an in vitro photothermal platform, GNR-layer was integrated with substrates to effectively apply heat stimulation to the cultured neurons. However, identifying optimal laser power for a targeted temperature on the substrate requires the consideration of thermal properties of the GNR-coated substrates. In this report, we suggest a simple numerical method to determine incident laser power on the substrates for a targeted temperature.

Temperature-sensitive properties of occluded hydration centers in direct hexagonal (HI) mesophases

Temperature-induced structural transformations of a direct hexagonal mesophase were investigated by SAXS, rheology, DSC, and NMR. The investigated mesophase region consists of two distinct direct hexagonal structures. The primary structure, detected at lower water content (33.0–39.0 wt%, 25 °C), is oriented as a bidiscontinuous assembly; it is composed of "occluded hydration centers" (OHCs) and direct surfactant-oil aggregates. The secondary structure, detected at higher water content (39.5–42.5 wt% water, 25 °C), is composed of an unbound water continuous phase and direct surfactant-oil aggregates.The OHCs within the bidiscontinuous mesophase were found to enhance the mesophase's order (correlation length (ξ)) and storage modulus (G′). The content of the unbound water occluded within the OHCs is temperature dependent, due to the ethoxylates’ water binding properties. At temperatures below 18 °C, the water in the bidiscontinuous mesophase (<39.0 wt% water) remains bound, resulting in a decreased mesophase order (correlation length (ξ)) and storage modulus (G′). Elevated temperatures increase the unbound water content, causing the unbound water domains to swell. Above the critical swelling point, the unbound water domains interlink to form a continuous phase, reducing the systems’ range order (ξ) and the storage modulus (G′).Better understanding the temperature dependence of the direct hexagonal mesophase enables mapping of the critical factors affecting the controlled delivery vehicles for non-bioavailable drugs.

A potential temperature sensing material: Studies of structure and temperature-sensitive photoluminescent properties of Nb5+, Sm3+ doped YTaO4

Non-contact luminescence temperature measurement technology shows a broad application prospect in medical, high-temperature environment and other fields, which has attracted people's attention for its high-precision, real-time response and so on. In this work, Nb5+, Sm3+ single-doped and co-doped YTaO4 phosphor was designed. YTaO4 with M-type and M′-type structures can be obtained by adjusting the synthesis conditions. The structure and composition of the samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Scanning electron microscopy (SEM). The photoluminescent properties of NbO43− group and Sm3+ ions in M-type and M′-type YTaO4 matrix were studied. Due to the different thermal responses of Nb5+ and Sm3+ ions, the fluorescence intensity ratio between them can be used as temperature detecting signal. In the range of 77–500 K, the maximum relative sensitivity of the YTaO4: Nb5+, Sm3+ reaches 1.15 %K−1 at 450 K, indicating that the Nb5+ and Sm3+ co-doped M-type YTaO4 phosphors can be used as optical temperature sensor. This research may provide guidance for the design of other rare earth doped luminescent materials for temperature detection.

Magnetized Bi-convective Nanofluid Flow and Entropy Production Using Temperature-sensitive Base Fluid Properties: A Unique Approach

The flow mechanism and entropy production of a bi-convective, magnetized, radiative nano-liquid flow for an inverted cone considering temperature-sensitive water properties is accomplished numerically. The functional nanomaterial comprises Copper, Alumina in the base liquid, water. The mathematical equations representing the system's physical characteristics are solved numerically by adopting a robust numerical approach for indulgencing non-similar solutions to understand numerous parameters' effect on temperature, velocity, salient gradients, and entropy production. The investigation summarizes that buoyancy force and injection heighten the velocity, and suction, particle percentage, radiation elevate the heat transfer. At the same time, the radiation and Brinkman number enhance the entropy generation. It is also detected from this investigation that the magnetic effect shows dual behaviour in entropy generation.

In-situ formed Cyclodextrin-functionalized graphene oxide / poly (N-isopropylacrylamide) nanocomposite hydrogel as an recovery adsorbent for phenol and microfluidic valve

Phenolic compounds are important industrial raw materials for various industrial applications, but phenol-containing wastewater creates significant environmental and biological hazards. To address these issues, a three-dimensional network graphene oxide-cyanoethyltriethoxysilane-β-cyclodextrin/poly (N-isopropylacrylamide) (GO-CTES-β-CD/PNIPAM) nanocomposite hydrogel as a phenol recovery adsorbent is prepared herein by in-situ polymerization. Double graft modification on the graphene oxide (GO) via the silane coupling agent 2-cyanoethyltriethoxysilane (CTES) and single (6-tetraethylenepentamine-6-deoxy)-β-cyclodextrin (NH-β-CD) compensated the loss of the active sites on both GO and N-isopropylacrylamide (NIPAM), and the hydrogel shows excellent mechanical properties as the chemical crosslinking and physical entanglement of the two components. Consequently, the composite hydrogel achieved an adsorption capacity of 131.64 mg·g−1 for the common environmental toxin 4-NP. After five repeated adsorption–desorption cycles, the hydrogel retained 74% of the initial 4-NP removal ratio. The adsorption results followed pseudo-first-order kinetics, corresponding to heterogeneous multilayer adsorption, which was regulated by a combination of surface adsorption and intra-particle diffusion mechanisms. In general, the nanocomposite hydrogel shows promising application in the field of recycling phenols from wastewater. Also, high photothermal conversion and temperature-sensitive properties are also demonstrated, which makes the hydrogel possessing great potential to be applied in smart microvalves.

Size-Dependent Catalytic Activity of PVA-Stabilized Palladium Nanoparticles in p-Nitrophenol Reduction: Using a Thermoresponsive Nanoreactor.

Palladium nanoparticles (Pd NPs) of various average global diameters (2.1–7.1 nm) encapsulated with hydrophilic polymer polyvinyl alcohol (PVA) have been synthesized and used as catalysts for sodium borohydride assisted reduction of p-nitrophenol to p-aminophenol. The synthesized catalysts exhibit excellent and typical size-dependent catalytic activity in the green protocol. UV–visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were employed to characterize the prepared Pd NPs. The kinetics of this reaction was easily monitored by a UV–visible absorption spectrophotometer. The mechanism of the reaction is explained by the Langmuir–Hinshelwood model. The catalytic performance increases with decreasing size of the synthesized nanoparticles. The apparent rate constants (kapp × 103/s–1) of the catalytic reduction in the presence of Pd NPs of average diameters of 2.1, 3.35, 6.2, and 7.1 nm are determined as 8.57, 7.67, 6.16, and 5.04, respectively, at 298 K by using 2.91 mol % palladium nanocatalyst in each case. Moreover, the estimated activation energy of 22.2 kJ mol–1 obtained for Pd NPs with the smallest average diameter of 2.1 nm is very low as reported in the literature for the reduction. The influences of catalyst dose and concentration of p-nitrophenol on catalytic reduction are fully investigated. The catalyst with the largest diameter shows a temperature-sensitive property that might be due to the presence of a very low amount of rapped PVA used as stabilizer during the fabrication process. Thus, the synthetic protocol provides a unique fabrication process of a catalytically active thermoresponsive nanoreactor consisting of Pd NPs encapsulated into a PVA stabilizing agent.

Temperature sensitive properties and preparation of europium complexes with double ligands

Temperature sensitive paints (TSPs) are a class of rising materials for non-contact temperature measurement technology. Efficient complexes with remarkable luminescent properties play the core role in TSPs. Rare earth organic complexes are often used as probe molecules for TSPs because of their long fluorescence lifetime, narrow fluorescence emission peaks, high fluorescence intensity, and large Stokes shift. Herein, two europium-based complexes, Eu(PCCA)3 phen and Eu (PMCA)3 phen, were synthesized under hydrothermal conditions, using europium(III) oxide (Eu2 O3 ), p-chlorocinnamic acid (PCCA), p-methoxy cinnamic acid (PMCA) and 1,10-phenanthroline (phen) as raw materials. Two temperature sensitive paints (Eu(PCCA)3 phen/PMMA and Eu(PMCA)3 phen/PMMA) were obtained by the polymerization of methyl methacrylate (MMA) with different europium complexes. The structure, morphology, luminescent properties of the europium complexes and temperature quenching properties of the TSPs were characterized by infrared (IR) spectroscopy, scanning electron microscopy (SEM), and fluorescence spectroscopy. The fluorescence results show that both of the two TSPs have good temperature quenching performance in the range 20-100°C with high sensitivity 50-60°C and 80-90°C, respectively. Furthermore, the highest sensitivity of Eu(PCCA)3 phen/PMMA is greater than that of Eu(PMCA)3 phen/PMMA. This work can provide a universal way for preparing efficient TSPs in practical applications.

Interpreting temperature effects in soils using thermally-enhanced viscoplastic model

The goal of this work is to show that the thermomechanical behaviour of soils can be interpreted as rate processes that are controlled by temperature-dependent viscous properties. A simple thermally-enhanced viscoplastic model is proposed that combines critical state soil mechanics and overstress viscoplasticity, and includes the dependence of viscosity parameters on environmental temperatures in a way consistent with the well-established Arrhenius law of chemical reactions. This modelling approach is shown to be able to reproduce many well-observed patterns of the temperature effects on the volumetric and distortional characteristics of soils. The application of the thermally-enhanced viscoplastic model in boundary value problems is demonstrated by analysing one-dimensional consolidation of saturated soils subjected to coupled mechanical and thermal loading. The connection between temperature-sensitive viscous properties and experimentally observed transient acceleration of secondary consolidation in soils subjected to heating is highlighted.

Effect of Biowaste on the High- and Low-Temperature Rheological Properties of Asphalt Binders

The growth of aquaculture has increased the production of oysters. However, the increased oyster shell volume has created serious environmental and recycling problems for the society. In order to study the sustainable utilization of waste oyster shells, asphalt binder of waste oyster shell powder was prepared by using modified asphalt material with waste oyster shells. The microstructure of oyster shell powder was analyzed by scanning electron microscopy experiments. The chemical composition of the asphalt binder was observed by Fourier transform infrared spectroscopy tests. The physical properties of the asphalt binder, including softness, high-temperature performance, and plastic deformation capacity, were initially evaluated through three indicators’ tests on asphalt. A preliminary performance evaluation of the asphalt binder was performed. The high-temperature stability of asphalt binders was evaluated using dynamic shear rheometry. The rutting resistance of the material was evaluated by temperature sweep tests, and the shear deformation resistance of the material was evaluated by frequency sweep tests. Multiple stress creep recovery tests determine the material’s ability to resist permanent deformation. The low-temperature rheological properties were evaluated by bending beam rheology tests. The study found that the waste oyster shell powder is a biomass with a porous irregular petal shape. No new characteristic absorption peaks are formed by mixing with asphalt. And, it can improve the viscosity, thermal stability, and temperature-sensitive properties of the material. It significantly improved the high-temperature rheological performance, rutting coefficient, and recovery elasticity of the material. However, it has little effect on low-temperature rheological performance. This study provides a solid foundation for the effective use of biowaste in engineering materials.

Lactobionic acid-modified chitosan thermosensitive hydrogels that lift lesions and promote repair in endoscopic submucosal dissection

To develop a biomaterial to lift the lesion and promote wound healing in endoscopic submucosal dissection (ESD), we used lactobionic acid (LA) to improve the water solubility of chitosan (CS) and prepared a new three-phase hydrogel system with lactobionic acid-modified chitosan/chitosan/β-glycerophosphate (CSLA/CS/GP). The results indicated that the hydrogel retains temperature-sensitive properties, and CSLA obviously improved the low-temperature fluidity of the hydrogel precursor solution, enabling injection of the hydrogel by endoscopic needle. The mechanical strength and bio-adhesion of the hydrogels were also improved by the addition of CSLA and the hydrogels could be maintained in acidic environment for a few days and exhibit greater protection of cells. The CSLA/CS/GP hydrogels show good cytocompatibility. The heights of cushions elevated by CSLA/CS/GP hydrogels remained ∼ 60 % 2 h post-injection in porcine stomach models. Given the unique characteristics of these materials, the CSLA/CS/GP thermo-sensitive hydrogel is a promising intraoperative biomaterial in ESD.

Tunable upconversion luminescence and enhanced temperature sensitive properties from Bi2Ti2O7:Yb3+/Er3+ nanofibers

Tunable upconversion luminescence and enhanced temperature sensitive properties from Bi2Ti2O7:Yb3+/Er3+ nanofibers

Injectable self-healing anti-inflammatory europium oxide-based dressing with high angiogenesis for improving wound healing and skin regeneration

Lanthanide-based nanomaterials have shown the promising applications in bioimaging and therapy due to their unique optical, magnetic and catalytic properties. However, the effect and promising application of lanthanide-based nanomaterials in wound healing and skin regeneration was rarely reported. Herein, we develop an injectable self-healing anti-inflammatory angiogenic europium oxide nanorods (Eu2O3 NRs) reinforced nanocomposites (FHAE) dressing and demonstrate the important role of Eu2O3 NRs in enhancing wound healing and skin regeneration. The FHAE dressing showed the temperature-sensitive, injectable, and self-healing properties, as well as the excellent cytocompatibility and blood compatibility. The in vivo mouse skin defect model experiments exhibited that FHAE dressing could significantly accelerate the wound healing and promote the skin appendage tissue regeneration through inhibiting inflammatory factors (TNF-α, IL-6) and enhancing the angiogenesis (α-SMA and CD31). This study suggests that Eu2O3-based biomaterials probably have promising applications in tissue engineering and regenerative medicine.

Tuning the photonic properties of graphene oxide suspensions with nanostructured additives.

Photonic materials that can selectively reflect light across the visible spectrum are valuable for applications in optical devices, sensors, and decoration. Although two-dimensional (2D) colloids that stack into layers with spacing of hundreds of nanometers are able to selectively diffract light, controlling their separation in solution has proven challenging. In this work, we investigate the role of additives to control the photonic properties of hybrid colloidal suspensions of graphene oxide (GO). We discovered that low concentrations of colloidal additives like cellulose nanocrystals (CNCs) and clay nanoparticles (hectorite) added to GO suspensions lead to dramatic color changes. These hybrid colloidal suspensions demonstrate tunable structural colors and temperature-sensitive properties that likely originate from the entropically driven ejection of guests between the sheets, and from the interactions between colloidal electrical double layers and additional counterions. On the other hand, blending polymeric or molecular additives with GO suspensions either deteriorates or does not impact the photonic properties. These results are helpful to understand the interaction between GO suspensions and additives over different length scales, and open a path to advancing photonic materials based on hybrid colloidal suspensions.

PEG-interpenetrated genipin-crosslinked dual-sensitive hydrogel/nanostructured lipid carrier compound formulation for topical drug administration

PEG-interpenetrated dual-sensitive hydrogels that load nano lipid carrier (NLC) were researched and developed for topical drug administration. Natural antioxidant α-lipoic acid (ALA) was selected as our model drug. The α-lipoic acid (ALA) nano lipid carrier was successfully prepared by hot melt emulsification and ultrasonic dispersion method, and the physicochemical properties of the nano lipid carrier were investigated, including morphology, particle distribution, polydispersity coefficient, zeta potential and encapsulation efficiency. Carboxymethyl chitosan and poloxamer 407 contributed to pH- and temperature-sensitive properties in the hydrogel, respectively. Natural non-toxic cross-linking agent genipin reacted with carboxymethyl chitosan to form the hydrogel. Poly ethylene glycol (PEG), a polymer compound with good water solubility and biocompatibility, interpenetrated the hydrogel and influenced the mechanical strength and drug release behaviour. FI-IR test verified the successful synthesis of the hydrogel. The rheological parameters indicated that the mechanical strength of the hydrogel was positively correlated with the amount of PEG, and the in vitro dissolution profiles demonstrated that the increasement of PEG could accelerate the drug release rate. The compatibility of the drug delivery system was verified with cells and mice model. Topical delivery of ALA in solution, NLC and NLC-gel was investigated in-vitro.

Human Mesenchymal Stem Cell Sheets Improve Uterine Incision Repair in a Rodent Hysterotomy Model.

The study aimed to assess the feasibility of creating and transplanting human umbilical cord mesenchymal stem cell sheets applied to a rat model of hysterotomy, and additionally to determine benefits of human umbilical cord mesenchymal stem cell sheet transplantation in reducing uterine fibrosis and scarring. Human umbilical cord mesenchymal stem cell sheets are generated by culturing human umbilical cord mesenchymal stem cells on thermo-responsive cell culture plates. The temperature-sensitive property of these culture dishes facilitates normal cell culture in a thin contiguous layer and allows for reliable recovery of intact stem cell sheets without use of destructive proteolytic enzymes.We developed a rat hysterotomy model using nude rats. The rat uterus has two distinct horns: one horn provided a control/untreated scarring site, while the second horn was the cell sheet transplantation site.On day 14 following surgery, complete uteri were harvested and subjected to histologic evaluations of all hysterotomy sites. The stem cell sheet culture process yielded human umbilical cord mesenchymal stem cell sheets with surface area of approximately 1 cm2.Mean myometrial thickness in the cell sheet-transplanted group was 274 μm compared with 191 μm in the control group (p = 0.02). Mean fibrotic surface area in the human umbilical cord mesenchymal stem cell sheet-transplanted group was 95,861 μm2 compared with 129,185 μm2 in the control group. Compared with control horn sites, cell sheet-transplanted horns exhibited significantly smaller fibrotic-to-normal myometrium ratios (0.18 vs. 0.27, respectively, p = 0.029). Mean number of fibroblasts in cell sheet-transplanted horns was significantly smaller than the control horns (483 vs. 716/mm2, respectively, p = 0.001). Human umbilical cord mesenchymal stem cell sheet transplantation is feasible in a rat model of hysterotomy. Furthermore, use of stem cell sheets reduces fibroblast infiltration and uterine scar fibrotic tissue formation during hysterotomy healing, potentially mitigating risks of uterine scar formation. · Stem cell sheet transplanted to hysterotomy promotes myometrial regeneration and reduced fibrotic tissue formation.. · This study demonstrates the feasibility of using human umbilical cord mesenchymal stem cell sheets..