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In this study, we synthesized lead-free 0.975(K 0.4 Na 0.6) 0.985 Li 0.015 (Nb 0.94 Sb 0.06)O 3 −0.025 (Bi 1− x Ho x) 0.5 Na 0.5 ZrO 3 (KNLNS−2.5Bi 1− x Ho x NZ) ceramics with excellent temperature stability and temperature-independent fatigue-free behavior. The doping with Ho3+ ions induced the phase transition from the coexisting orthorhombic (O) − tetragonal (T) crystal phase into pure T symmetry, increasing the T:O ratio. The large-signal piezoelectric constant, d 33 *, of the synthesized KNLNS−2.5Bi 1− x Ho x NZ ceramics is almost constant in the temperature range from 30 to 120 °C. In-situ dielectric permittivity measurement indicated that the O − T phase transition becomes more diffuse in the electrical field, contributing to improved thermal stability. Furthermore, the Ho-doped ceramics exhibited a fatigue-free behavior regardless of the temperature, rendering these materials promising for actuator applications. Besides, the Ho-modified ceramics showed excellent photoluminescence (PL) properties with strong green light emission upon 453 nm visible light excitation. Polarization- and temperature-induced PL quenching behaviors were observed. These changes may originate from the electric field- or temperature-induced phase transitions from the mixed O − T to pure T crystal symmetry. These excellent and reliable electrical and photoluminescent properties reflect the great potential of the synthesized ceramics for applications in multifunctional devices. [ABSTRACT FROM AUTHOR]

In this work, a scandium-doped aluminum nitride (ScAlN)-based piezoelectric breathing mode dual-ring resonator with high temperature stability is presented. The designed resonator consists of two identical rings and a coupling straight beam in between. A combination of highly doped silicon and composite structure using silicon oxide is implemented to improve the frequency-temperature stability of the resonator. The dual-ring resonator is fabricated based on a ScAlN-based thin-film piezoelectric-on‑silicon (TPoS) platform. The measurement results show that the fabricated dual-ring resonator has a loaded quality factor (Q l) of 6889 and an insertion loss of 13.898 dB at its resonant frequency of 16.766 MHz, corresponding to a motional resistance of 395 Ω , and an unloaded quality factor (Q un) of 8681. The resonator's Q un is almost constant within the pressure range of less than 300 Pa, indicating a good process tolerance in the vacuum packaging process. With the aid of the passive temperature compensation, the reported resonator exhibits an overall frequency variation of less than ±70 ppm over the entire temperature range of 20 °C to 105 °C, which agrees well with the predicted value obtained by finite element method (FEM) analysis. Moreover, Allan deviations of the resonator-based oscillator frequency are collected. [Display omitted] • A combination of highly doped silicon and composite structure using silicon oxide is implemented to improve the frequency-temperature stability of the resonator. • The reported resonator exhibits an overall frequency variation of less than ±70 ppm over the entire temperature range of 20 °C to 105 °C. • The resonator's unloaded quality factor (Q un) is almost constant within the pressure range of less than 300 Pa, indicating a good process tolerance in the vacuum packaging process. [ABSTRACT FROM AUTHOR]

In this work, the preparation of Li 3 (Mg 4-x Cu x)NbO 8 (0.01 ≤ x ≤ 0.04) was accomplished using the solid-state reaction method. Based on Rietveld refinement, microscopic morphology, and the complex chemical bonding theory, the influence of Cu2+ introduction on the microwave dielectric properties of Li 3 Mg 4 NbO 8 ceramics was investigated, revealing the relationship between crystal structure and dielectric properties. The ε r was affected by both the relative density and ionic polarizability. A moderate amount of Cu2+ (x = 0.02) substitution for Mg2+ increased the lattice energy, which could enhance the Q × f value. Additionally, the τ f value also moved towards near zero because of the improvement in Nb-O 6 octahedral distortion. Outstanding dielectric properties were achieved for Li 3 (Mg 3.98 Cu 0.02)NbO 8 ceramics at 1075 °C: ε r ∼13.59, Q × f ∼115,444 GHz, τ f ∼-11.19 ppm/°C. Compared to pure Li 3 Mg 4 NbO 8 ceramics, its Q × f value increased by 11.6%, and τ f increased by 68.9%. • The effects of Cu2+ introduction on Li 3 Mg 4 NbO 8 ceramics are analyzed. • The Li 3 (Mg 4-x Cu x)NbO 8 ceramics show improved Q × f and good temperature stability. • The correlations between crystal structure and properties are investigated. [ABSTRACT FROM AUTHOR]

The 0.65(Bi 0.5 Na 0.5)TiO 3 –0.35SrTiO 3 -based materials are essential for the development of pulse power capacitors. However, their low recoverable energy storage density and breakdown field strength have hindered further improvement. To address this, a high-entropy strategy based on multiscale regulation is proposed, which involves synergistically manipulating the activation energy and microstructure evolution in BNST-based ceramics through the introduction of Ba(Zr 0.2 Ti 0.2 Sn 0.2 Hf 0.2 Ta 0.2)O 3. The inclusion of high-insulating oxides can significantly raise the activation energy of the entire system. Furthermore, the high-entropy material can significantly increase the atomic disorder and lattice distortion, resulting in strong local polar fluctuations on several nanoscales and excellent energy storage characteristics. As a result, this approach yields an impressive W rec of ∼ 4.89 J/cm3 and a high efficiency of ∼92.1 % at 351 kV/cm, and the outstanding thermal endurance (20∼150 °C), frequency stability (5∼1000 Hz) and fatigue (100∼105 cycles). This study provides an effective strategy for achieving excellent comprehensive performances in high-entropy ceramics. [Display omitted] [ABSTRACT FROM AUTHOR]

Antiferroelectric materials exhibit fantastic application potential in multifunctional devices due to their special structure and polarization/strain-electric field responses. However, it has long been challenging to realize multifunctionality in PbHfO 3 , one of the prototypical antiferroelectrics, due to its poor sinterability and structural complexity. To address these issues, we report an effective strategy to obtain fine and dense PbHfO 3 ceramics by the solid-state reaction method involving a liquid phase sintering mechanism. The crystal structure, microstructure, phase transitions, energy storage, and strain performance are systematically investigated. A high recoverable energy density W reco (7.29 J/cm3) and a large strain (0.51%) are achieved with a temperature-stable (25 ∼ 175 °C) feature. By combination of synchrotron and laboratorial X-ray diffraction, Raman spectroscopy, dielectric and impedance spectroscopy, and density-functional-theory calculations, the high and temperature-stable energy-storage and strain properties are determined to arise from the stable antiferroelectric nature of PbHfO 3 with a large polarization in a broad temperature range and its transformation to a ferroelectric phase with R 3 c symmetry under electric field. Furthermore, the ceramics present a negative temperature coefficient of resistance in a higher temperature range of 400 ∼ 600 °C. These performances grant PbHfO 3 antiferroelectric ceramics a huge potential for applications in high-density energy storage capacitors, large-displacement actuators, and temperature sensors and compensators over a broad temperature range. High performances of Pb (1+x) HfO 3 for multifunctional applications [Display omitted] [ABSTRACT FROM AUTHOR]

Ferroelectrics with a high dielectric constant are ideal materials for the fabrication of miniaturized and integrated electronic devices. However, the dielectric constant of ferroelectrics varies significantly with the change of temperature, which is detrimental to the working stability of electronic devices. This work demonstrates a new strategy to design a ferroelectric dielectric with a high temperature stability, that is, the design of a multilayer relaxor ferroelectric thin film with a composition gradient. As a result, the fabricated up-graded (Pb,La)(Zr0.65,Ti0.35)O3 multilayer thin film showed a superior temperature stability of the dielectric constant, with variation less than 7% in the temperature range from 30 °C to 200 °C, and more importantly, the variation was less than 2.5% in the temperature range from 75 °C to 200 °C. This work not only develops a dielectric material with superior temperature stability, but also demonstrates a promising method to enhance the temperature stability of ferroelectrics.

The Taiji-1 satellite is a pioneering space technology mission designed by the Chinese Academy of Science (CAS) to test key technologies required for gravitational wave detection in space. Temperature stability is a critical element because it can couple with the gravitational wave measurement. A dedicated thermal control with a three-level control method was used on the Taiji-1 satellite science module. The simulation analysis shows that the temperature stability control level of its scientific instrument temperature stability can reach ± 1.7 mK. Combined with the in-orbit temperature results, the temperature stability obtained by using the linear smoothing filter and the Kalman filter reached ± 1.1 and ± 0.5 mK, respectively, which were in good concerted with the simulation data, indicating that the thermal control level of Taiji-1satellite science module reached a high precision. [ABSTRACT FROM AUTHOR]

NBT-xBT@BT-BZN composite ceramic materials were prepared by wet solid-phase reaction method. The effects of NBT-xBT (x = 6, 7, 8, 9 mol%) on the phase structure, morphology and dielectric properties of NBT-xBT@BT-BZN composites were studied in detail. It is found that the introduction of BT into NBT leads to enhanced temperature stability in dielectric property. Samples with NBT-0.07BT shows good dielectric property, in which the temperature change rate of the dielectric constant at −55 °C–200 °C is −0.1% to −14.5%, meeting the requirements of X9R. These results indicate that the NBT-0.07BT@BT-BZN is a promising candidate for high temperature stable materials. [ABSTRACT FROM AUTHOR]

NBT-xBT@BT-BZN composite ceramic materials were prepared by wet solid-phase reaction method. The effects of NBT-xBT (x=6, 7, 8, 9 mol%) on the phase structure, morphology and dielectric properties of NBT-xBT@BT-BZN composites were studied in detail. It is found that the introduction of BT into NBT leads to enhanced temperature stability in dielectric property. Samples with NBT-0.07BT shows good dielectric property, in which the temperature change rate of the dielectric constant at -55 °C-200 °C is -0.1% to -14.5%, meeting the requirements of X9R. These results indicate that the NBT-0.07BT@BT-BZN is a promising candidate for high temperature stable materials. [ABSTRACT FROM AUTHOR]

NixFe3−xO4 ferrites (x = 0.6, 0.7, 0.8, 0.9, 1.0) were prepared by solid-phase reaction method. Structure and morphology were characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM). Magnetic properties were measured with B-H analyzer and magnetic properties measurement system (MPMS). NixFe3−xO4 ferrites with high Ni2+ content (x = 0.7 ~ 1.0) present pure cubic spinel phase and dense microstructure. Their saturation magnetization (Ms) and initial permeability (μi) decrease with x increasing. Temperature coefficient (αμ) and specific temperature coefficient (β) were calculated based on the permeability from -60 °C to 100 °C. The results show both of αμ and β decrease with x decreasing, indicating that proper reduction of Ni2+ content and increasing Fe2+ content help to improve the temperature stability of NixFe3-xO4. This improvement in temperature stability is attributed to the influence of Fe2+ in the ferrites on the magnetocrystalline anisotropy. [ABSTRACT FROM AUTHOR]

High performance colossal permittivity ceramic materials are indispensable for the development of electronic devices. In this work, Mg and Nb co-doping BaTiO 3 ceramics were prepared by solid-state reaction under reducing atmosphere. The polarization mechanism, dielectric properties and insulation mechanism were investigated. The defect dipoles ( [ M g T i ″ − V O • • ] × and [ M g T i ″ − 2 N b T i • ] ×) could be formed inside co-doping BaTiO 3 ceramics with various content of MgO, which is the source of colossal permittivity. Appropriate MgO content doping is favorable to enhance short-range hopping, thus improve grain resistance, grain boundary resistance and grain boundary activation energy. The 1.0 at% MgO modified BaTiO 3 -0.01Nb 2 O 5 ceramics possess excellent performance at room temperature with colossal dielectric constant (ԑ r = 4.5 × 104), low dielectric loss (tanδ<0.018), and high insulation resistivity (ρ v = 6.52 × 1011 Ω cm). Meanwhile, good temperature stability is obtained in 1.0 at% MgO modified BaTiO 3 -0.01Nb 2 O 5 ceramics, which satisfies the Electronic Industries Association (EIA) X8R (−55–150 °C, △ε r /ε 25 ≤ ±15%) specification. This study suggests that the defect-dipoles related polarization mechanism can be used to design the colossal permittivity BaTiO 3 -based ceramics. [ABSTRACT FROM AUTHOR]

The 1–3 piezoelectric composites are an important type of artificial functional materials for ultrasonic transducers. Currently, there are increasingly strong demands to replace the lead-containing materials. Excellent 1–3 0.96(K 0.48 Na 0.52) (Nb 0.96 Sb 0.04)O 3 −0.03BaZrO 3 −0.01(Bi 0.50 Na 0.50)ZrO 3 ceramic/epoxy (abbreviated hereafter as KNNS-0.03BZ-0.01BNZ/epoxy) piezoelectric composites were prepared by a modified dice-and-fill technique. Compared to the monolithic KNNS-0.03BZ-0.01BNZ ceramic, the developed composites possess much larger electromechanical coupling coefficient k t of 0.54–0.67 and piezoelectric voltage coefficient g 33 of 64–91 × 10−3 Vm/N. In addition, these composites also possess other favorable properties such as low values of acoustic impedance Z of 6.9–13.4 Mrayl, dielectric coefficient ε 33 of 130–400 and mechanical quality factor Q m of 1.3–4. More importantly, k t is weakly temperature-dependence in the common usage temperature range between −30 °C and 100 °C. The result indicates that the 1–3 KNNS-0.03BZ-0.01BNZ/epoxy piezoelectric composites have a great potential for high-frequency ultrasonic transducers. [ABSTRACT FROM AUTHOR]

The spread of multidrug-resistant bacteria poses a significant threat to human health. Plasma activated liquids (PAL) could be a promising alternative for microbial decontamination, where different PAL can possess diverse antimicrobial efficacies and cytotoxic profiles, depending on the range and concentration of their reactive chemical species. In this research, the biological activity of plasma activated water (PAW) on different biological targets including both microbiological and mammalian cells was investigated in vitro. The aim was to further an understanding of the specific role of distinct plasma reactive species, which is required to tailor plasma activated liquids for use in applications where high antimicrobial activity is required without adversely affecting the biology of eukaryotic cells. PAW was generated by glow and spark discharges, which provide selective generation of hydrogen peroxide, nitrite and nitrate in the liquid. The PAW made by either spark or glow discharges showed similar antimicrobial efficacy and stability of activity, despite the very different reactive oxygen species (ROS) and reactive nitrogen species profiles (RNS). However, different trends were observed for cytotoxic activities and effects on enzyme function, which were translated through the selective chemical species generation. These findings indicate very distinct mechanisms of action which may be exploited when tailoring plasma activated liquids to various applications. A remarkable stability to heat and pressure was noted for PAW generated with this set up, which broadens the application potential. These features also suggest that post plasma modifications and post generation stability can be harnessed as a further means of modulating the chemistry, activity and mode of delivery of plasma functionalised liquids. Overall, these results further understanding on how PAL generation may be tuned to provide candidate disinfectant agents for biomedical application or for bio-decontamination in diverse areas. [ABSTRACT FROM AUTHOR]

Grape molasses is a traditional sweet with high nutritional value. One factor limiting the production and storage of grape molasse halva Gazi is related to the thermal sensitivity of its texture properties and decreasing its quality during storage at ambient temperature. Therefore, this study aimed to improve the texture properties of the newly formulated halva during storage at different temperatures. Different levels of gums (0.5 %, 1 % & 1.5 %) including alginate, carrageenan, xanthan, and their blends (0.5 %-0.5 %) were used as additives in the formulation of halva to improve its texture during 48 h storage at 25 °C and 40 °C. The texture analysis tests were then performed to evaluate the firmness and fracturability of the halva. The results showed that the combination of gums, as well as using xanthan gum alone, produced an appropriate and soft texture in comparison to the control halva (0 % gum). However, the halva containing carrageenan-alginate blends showed the softest texture. The samples containing 0.5 and 1 % of alginate and xanthan as well as xanthan-alginate blend and xanthan-carrageenan blend had the best texture properties during storage at 40 °C.

A CMOS-compatible carrier-injection plasmonic micro-ring modulator (CIPMRM) is proposed and theoretically analyzed. It has a compacted footprint of 43.4 μm2 (R = 2 μm), a data rate of 45 Gbps, an insertion loss of −8 dB, a static extinction ratio of 22 dB, and an energy consumption of 4.5 pJ/bit when 2.5 V peak-to-peak voltage is applied. Moreover, it works well when temperature varies around 60 K. A method of tuning the resonant wavelength based on the carrier concentration is proposed here because the device is reliable when the linewidth varies within ±5%. CIPMRM provides a way to overcome the shortcomings of temperature and process sensitivity, which are characteristics of the photonic micro-ring modulator. It can be used in optoelectronic integration for its small size and stable performance.

The temperature stability of electron transfer to the artificial electron acceptor 2,6-dichlorophenolindophenol in preparations of native photosystem II and photosystem II without the calcium cation in an oxygen-evolving complex was studied. The thermal stability of the processes of oxygen evolution and electron transfer from the oxygen-evolving complex to 2,6-dichlorophenolindophenol in photosystem II were significantly different: the reduction of 2,6-dichlorophenolindophenol was more resistant to temperature than oxygen evolution. The reaction of 2,6-dichlorophenolindophenol reduction in the Ca2+-depleted preparations of photosystem II was less resistant to heating than in the preparations of native photosystem II. The thermal inactivation of the photosystem II in the Ca2+-depleted membrane preparations was inhibited by cytochrome c at a concentration of 50 cytochrome c molecules per a photosystem II reaction center. The activity of this preparation (the rate of the 2,6-dichlorophenolindophenol reduction) increased by 19%, approaching the activity of the native photosystem II. The protective effect of cytochrome c appears to be determined by its protein nature, rather than its redox activity, since an equal protective effect was observed upon the addition of albumin at a similar concentration. Almost complete inactivation of the 2,6-dichlorophenolindophenol reduction reaction in the native and Ca2+-depleted preparations of photosystem II was observed at the same temperature (50°C). According to the EPR data, photosystem II in the Ca2+-depleted preparation after incubation at this temperature lacked a manganese cluster, while a peripheral protein of 33 kDa was present. [ABSTRACT FROM AUTHOR]

High capacity for the dielectric capacitors are necessary for practical applications. Additionally, dielectric capacitors should have some degree of temperature and frequency stability to allow them to adapt to environmental changes. To fulfil these requirements, Na 0.425 Bi 0.425 Ca 0.15 TiO 3 - x Dy (x = 0, 2, 5, and 10 at‰) (NBCT- x Dy) energy storage ceramics were produced using a traditional solid-state synthesis method. NBCT-5Dy achieved an excellent energy storage density of 2.35 J/cm3 and a good efficiency of 78.32% at 210 kV/cm. In addition, the sample was tested at 150 kV/cm under variable temperature and frequency conditions, showed a stable energy storage density of ~1.3 J/cm3 and maintains excellent efficiency at 30–150 °C and 0.2–200 Hz. Furthermore, the dielectric constant of the sample was measured at 0–40 kV/cm, and exhibited less than 2% change over this range. These results confirmed that the sample had excellent energy storage density and good stability. In the pulse discharge performance test, a high power density (46.31 MW/cm3 at 150 kV/cm) was obtained, indicating that this material has great application prospects in the pulse capacitor field in the future. [ABSTRACT FROM AUTHOR]

(Bi 1/2 Na 1/2)TiO 3 -based materials have received much attention due to large electro-strain and high piezoelectric constant (d 33), but the tough issue is that the existence of inherent depolarization temperature (T d) limits the temperature stability and application temperature range. Previously, reports about the formation of BNT/oxide (i.e., ZnO, Al 2 O 3) composites thought that T d can be deferred to a higher temperature and then thermal depolarization improves. However, the deferred T d of BNT/oxide composites is limited, accompanied by a low d 33. Here, we design the {[Bi 0.5 (Na 0.8 K 0.2) 0.5 ] 1- x Pb x }TiO 3 ceramics, leading to a big shift of T d from 77 ℃ to 390 ℃. Large d 33 (140 pC/N) and high T d (∼263 ℃) can be simultaneously achieved for the sample with Pb=0.05, and T d could be further deferred higher (390 ℃) for Pb=0.20. The off-centre displacement of Pb induced by Pb-O hybridization in the PbO 12 polyhedron and ferroelectric order stabilized by the addition of Pb can provide the driving force to strengthen the ferroelectric order, and then promote the thermal stability. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric (FE) materials have received increasing attention owing to their great potentials for energy-storage applications, especially for the ones with high energy-storage density, efficiency and thermal stability simultaneously. A novel lead-free [(Na 0.5 K 0.5) 0.97-x Li 0.03 ](Nb 0.94-x Sb 0.06)O 3 - x Bi(Zn 1/2 Zr 1/2)O 3 (NKLNS- x BZZ) ceramics was developed by a solid-state reaction method. The addition of BZZ has induced obvious dielectric relaxation behavior, as well as improved thermal stability of dielectric response. Furthermore, 0.4 wt.% La 2 O 3 was added into the NKLNS-0.06BZZ ceramic, leading to an increased breakdown strength as a result of the reduction of grain size, improvement of bulk resistivity and decrease of dielectric loss. A large recoverable energy-storage density (∼4.85 J/cm3) and a high efficiency (∼88.2 %) as well as an excellent thermal stability (±12 %, 25–140 °C) were simultaneously obtained, together with a fast discharge rate (t 0.9 ∼112 ns). These results suggest that La 2 O 3 doped NKLNS-0.06BZZ ceramic could become an attractive dielectric material for temperature-stable energy-storage capacitors. [ABSTRACT FROM AUTHOR]

Love wave sensors have attracted significant interest due to their high sensitivity and low attenuation. Love mode acoustic dispersion relation, highest normalized mass sensitivity, optimum normalized waveguide layer thickness, and temperature coefficients of frequency (TCF) were theoretically studied for the carbon fiber epoxy composites (CFEC)/Mn:0.24PIN-0.46PMN-0.30PT structure sensor. The highest normalized mass sensitivity exhibits a decreasing trend as the temperature increases from 25 °C to 55 °C. TCF can be improved by increasing the normalized layer thickness (h/λ); however, the temperature dependence of normalized mass sensitivity decreases. For the carbon fibers (CFs) in the CFEC waveguide along the propagation direction of Love wave, the device has a relatively small TCF of −10.92 ppm/°C at h/λ = 0.4001, where the normalized mass sensitivity is approximately 1.5 times that of a typical fused quartz/ST-quartz configuration device. The theoretical results imply that good temperature stability and high measurement precision were obtained from the device in the system CFEC/Mn:0.24PIN-0.46PMN-0.30PT with the CFs in the CFEC along the propagation direction of Love wave (x-axis). The ideal waveguide material requires a small elastic constant c 44 ; however, the ideal piezoelectric substrate requires large elastic constants c 44 E and c 66 E . [ABSTRACT FROM AUTHOR]

The formation of a morphotropic phase boundary (MPB) in piezoelectric ceramics is one of the most important techniques to enhance their dielectric and piezoelectric properties. In this work, a rhombohedral (R) and tetragonal (T) phase boundary has been designed and clarified using the lead‒free 0.92(Na0.5K0.5)NbO3–(0.08–x)(Bi0.5Li0.5)TiO3–xBaZrO3 ternary system. The R-T phase coexistence region is identified in the ceramics with 0.06 ≤ x ≤ 0.07. We successfully demonstrated that the crystal's relatively enhanced d33 and its excellent temperature stability are originated from phase transition behaviors that were confirmed by the temperature‒dependent dielectric properties and X−ray diffraction (XRD) patterns. [ABSTRACT FROM AUTHOR]

Here, B‐site doped 0.725BiFe0.98M0.02O3‐0.275BaTiO3 (M = Fe, Sc, Ga, and Al) + 0.8 mol% MnO2 (abbreviated as BF, BS, BG, and BA) (BFM‐BT) ceramics were designed and prepared to modulate octahedral distortions. According to bond‐valence calculations based on XRD Rietveld refinement data, B‐site doped BFM‐BT ceramics tended to have a higher distortion as the radius of the doping ion decreases, and obtained a great improvement of ferroelectric and piezoelectric performances. B‐site‐doped BFM‐BT ceramics significantly inhibited the formation of impurities, leading to better ferroelectric and piezoelectric performances. The BFM‐BT ceramics exhibited high Curie temperature of 519‐530℃ and good temperature stability for piezoelectric performances. The d33 values of BF, BS, and BA ceramics remained the room temperature value ranging from room temperature to 470℃. Meanwhile the content of impure phases, oxygen vacancies and valence of Fe3+ to Fe2+ decreased with the decreasing radii of B‐site doping ions. [ABSTRACT FROM AUTHOR]

The temperature stability of bentonite greases based on petroleum (I-40A) and synthetic (PAO-10) oils with the addition of PTFE, molybdenum disulfide, and boron nitride were evaluated. It was found that bentonite lubricants prepared on the basis of industrial oil I-40A have a higher lubricating ability than compared greases based on polyalphaolefine oil PAO-10. [ABSTRACT FROM AUTHOR]

The experimental data on the ion-plasma (13.56 MHz) magnetron sputtering of composite targets of the system W-B are presented. Application of this method allows one to obtain deposited alloys in the entire concentration range of compositions. The as-deposited films show the formation of an amorphous solid state. The decomposition of an amorphous state is accompanied by precipitation of an intermediate metastable, nanocrystalline W-phase with FCC-structure. By applying magnetron sputtering, we have obtained an amorphous state in pure W-films at room temperature. The thermal stability, electrical and mechanical properties of metastable states in W-B films are studied. The study shows that the amorphous state in the WB5 alloy is characterized by abnormally high temperature stability and microhardness. The ion-plasma sputtering method has demonstrated its effectiveness in the case of tungsten films, showing the possibility of obtaining metastable phases in them. At the same time, the obtained values of microhardness in the amorphous alloy turned out to be lower than the predicted maximum theoretical values due to the peculiarities of the location of atoms in the alloy. [ABSTRACT FROM AUTHOR]

Background: Physiologic-based cord clamping (PBCC) involves deferring umbilical cord clamping until after lung aeration. It is unclear if infant is at risk of becoming hypothermic during PBCC.Objectives: To test if PBCC would maintain core temperature more effectively than immediate cord clamping (ICC).Design: At 0.93 gestation, fetal lambs were surgically exteriorized and instrumented from pregnant ewes under general anesthesia. Prior to the start of the experiment, lambs were thoroughly dried, placed on hot water bottles, and core temperature was continuously monitored using a rectal thermometer. PBCC lambs (n = 21), received intermittent positive pressure ventilation (iPPV) for ≥5 min prior to umbilical cord clamping. In ICC lambs (n = 23), iPPV commenced within 60 s after umbilical cord clamping. iPPV was provided with heated/humidified gas. Lambs were moved under a radiant warmer after umbilical cord clamping. Additional warmth was provided using a plastic overlay, hairdryer, and extra water bottles, as needed. Two-way mixed and repeated measures one-way ANOVAs were used to compare temperature changes between and within a single group, respectively, over time.Results: Basal fetal parameters including core temperature were similar between groups. ICC lambs had a significant reduction in temperature compared to PBCC lambs (p < 0.001), evident by 1 min (p = 0.002). ICC lambs decreased temperature by 0.51°C (± 0.42) and 0.79°C (± 0.55) at 5 and 10 min respectively (p < 0.001). In PBCC lambs, temperature did not significantly change before or after umbilical cord clamping (p = 0.4 and p = 0.3, respectively).Conclusions: PBCC stabilized core temperature at delivery better than ICC in term lambs. Hypothermia may not be a significant risk during PBCC.

The on-site measurement of transient voltages is of great significance in analyzing the fault cause of power systems and optimizing the insulation coordination of power equipment. Conventional voltage transformers normally have a narrow bandwidth and are unable to accurately measure various transient voltages in power systems. In this paper, a wideband parallel resistive–capacitive voltage divider is developed, which can be used for online monitoring of transient voltages in a 220 kV power grid. The structures of the high-voltage and low-voltage arms were designed. The internal electric field distribution of the high-voltage arm was analyzed. The influence factors and improvement techniques of the upper frequency limit were studied. The parameters of the elements of the divider were determined. The voltage withstand performances and scale factors under lightning impulses and AC and DC voltages, the temperature stabilities of scale factors and the step response and bandwidth of the developed voltage divider were tested. The results show that the deviations of the scale factors under various voltage waveforms and different temperatures ranging from −20 to 40 °C are within 3%. The withstand voltage meets the relevant requirements specified in IEC60071-1-2011. The step response 10~90% rise time is approximately 29 ns, and the 3 dB bandwidth covers the range of DC to 10 MHz.

The maximum operation temperature of the vanadium solution in vanadium flow batteries is typically limited to 40 °C to prevent the damaging thermal precipitation of V2O5. Therefore, the operation of batteries at high ambient temperatures is an important aspect to tackle for stationary storage. In the present work, a comprehensive study of the high temperature stability of redox solutions for vanadium flow batteries was performed. In particular, focus was placed on a comparison between batch and in operando precipitation experiments. It was found that, despite being a widely used method in the literature, caution should be taken when assessing the precipitation through capacity fade due to the large influence of external oxidation and cycling parameters, plausibly leading to an incorrect interpretation of the results. The in operando experiments consistently show a precipitation temperature almost 10–20 °C higher than in the batch tests at a 100% state of charge for the same time lapse.

Silicon avalanche photodetector (APD) plays a very important role in near-infrared light detection due to its linear controllable gain and attractive manufacturing cost. In this paper, a silicon APD with punch-through structure is designed and fabricated by standard 0.5 μm complementary metal oxide semiconductor (CMOS) technology. The proposed structure eliminates the requirements for wafer-thinning and the double-side metallization process by most commercial Si APD products. The fabricated device shows very low level dark current of several tens Picoamperes and ultra-high multiplication gain of ~4600 at near-infrared wavelength. The ultra-low extracted temperature coefficient of the breakdown voltage is 0.077 V/K. The high performance provides a promising solution for near-infrared weak light detection.

Polyethersulfone (PES) and hollow glass microspheres (HGB) were used as fillers to modify the epoxy resin, and its effect on the mechanical and thermal properties of the epoxy polymer phase was studied. The research found that when epoxy polymer phase was prepared with 1 Owt% PES or HGB loadings, the shear strength increased from 39 MPa to 52 MPa? the thermal expansion coefficient decreased from 8.8 X 1 ()_r)/K to 5.8 X 10_5/K? and the mechanical and thermal properties of the material were significantly improved. Using PZT-4 as the piezoelectric phase? a 1 -3 type piezoelectric composite material with a PES and HGB filling content of 10% by weight was prepared by a cutting and filling method. The influence of temperature on resonance frequency /s and electromechanical coupling coefficient kt was measured by impedance analyzer. The results show that the /s of 1-3 piezoelectric composites was 885 kHz and kt was ().65. The change rate of /s and kt of the material within the range of 15-5() °C was less than 1% which showed good temperature stability. [ABSTRACT FROM AUTHOR]

In this study, (1- x)(0.66Bi 0.5 Na 0.5 TiO 3 –0.34Bi 0.2 Sr 0.7 TiO 3)– x K 0.5 Nd 0.5 TiO 3 (BNBST– x KNT) ceramics were designed and synthesized, and they present significantly enhanced dielectric temperature stability and energy storage properties. The BNBST–0.06KNT composition exhibits a remarkable dielectric stability, as reflected in its stable dielectric constant (△ ԑ / ԑ 150 °C < ±15%) over a broad temperature range (25–401 °C). BNBST–0.02KNT achieves a high energy storage density W rec = 1.2 J/cm3 under 110 kV/cm with an energy storage efficiency η of 76.9%, and the improved energy storage property originates from the improved breakdown field strength and decreased hysteresis behavior. The electrical conductivity and relaxation behaviors of BNBST– x KNT were also analyzed via impedance spectroscopy. [ABSTRACT FROM AUTHOR]

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Based on the transverse electro-optic effect of lithium niobate crystal, combined with polarizers and Faraday rotator, this paper presents a collinear closed-loop fiber optic current transformer with spatial non-reciprocity modulation method, and the feasibility of the scheme is verified by both the theoretical and experimental evidences. The detection scheme avoids the limitation of the transition time of the sensing fiber coil on the phase modulation frequency, improves the sensitivity and stability of the system, and reduces the volume and cost of fiber optic current transformer. The sawtooth wave modulation scheme is adopted to realize phase bias modulation and feedback modulation through phase shift of sawtooth wave to achieve closed-loop detection effect, which enhances the signal to noise ratio and simplifies demodulation mode. The experimental results show that the current ratio errors measured at room temperature range from 1% to 120% of rated current meet the requirements of national standard GB/T 20840.8-2007 and reach the accuracy level of 0.2S. The temperature stability of the current transformer is also tested, and the ratio error measured at the rated current does not exceed ±0.2% in the range of -30 °C to 50 °C. [ABSTRACT FROM AUTHOR]

Lead-free (1- x)Ba(Ti 0.8 Zr 0.2)O 3 - x (Ba 0.7 Ca 0.3)TiO 3 (BZT-BCT) possesses comparable piezoelectric constant with lead zirconate titanate (PZT), but its poor temperature electric performances stability and low Curie temperature limit its application. Here we designed composition graded BZT-BCT films with improved temperature stability of piezoelectric, ferroelectric, and dielectric performances over a wide temperature range, and the d 33 reaches 21 pm/V with hysteresis loop even at 180 °C, which is far above the Curie temperature of BZT-BCT ceramic and BZT-0.5BCT film. The excellent temperature stability is ascribed to the lattice distortion and strain gradient in the grains caused by ions diffusion, and could suppress phase transition. This work could bring forward a feasible design for dielectric/piezoelectric/ferroelectric devices operating in harsh temperature environment. [ABSTRACT FROM AUTHOR]

Featured Application: The circulating cooling water machine proposed in this paper is conductive to the thermal management of equipment and facilities in the field of precision manufacturing and measurement. It has already been applied to our lithography development project. An enhanced circulating cooling water (CCW) machine is developed to simultaneously achieve high temperature stability and dynamic performance of CCW temperature control. Dynamic thermal filtering based on an auto-updatable thermal capacity medium is proposed to reduce the temperature fluctuation of the CCW. Agile thermal control is presented to realize a quick response and high resolution of temperature control, through thermal inertia minimization and bidirectional regulation of heating/cooling power. Experimental results indicate that a temperature stability of ±3 mK (peak to peak value) and a settling time of 128 s, corresponding to a 1 K step set value, are achieved. It can therefore be concluded that the developed machine can satisfy the challenging requirements of precision manufacturing. [ABSTRACT FROM AUTHOR]

High power piezoelectric ceramics 0.04Bi(Ni 1/2 Ti 1/2)O 3 - x Pb(Mn 1/3 Nb 2/3)O 3 -(0.96- x)Pb(Zr y Ti 1- y)O 3 (BNT- x PMnN-PZ y T) with various contents of PMnN from 0 to 12 mol% (keep y = 0.50) and Zr/Ti ratio gradually increasing from 48/52 to 52/48 (keep x = 0.06) were prepared by solid-state method. X-ray diffraction (XRD) results show a single phase of polycrystalline perovskite and indicate that the phase structure transforms from tetragonal phase to rhombohedral with x and y increasing. The optimal comprehensive properties of BNT- x PMnN-PZ y T ceramic, d 33 (355 pC/N), k p (0.58), ε r (1512), tanδ (0.40%), T c (336 °C) and Q m (2010), are obtained at x = 0.06 and y = 0.50, which are apparently superior to typical or commercial Pb(Zr,Ti)O 3 (PZT) based power ceramics. Within the range from room temperature to 200 °C, the variation of electric-field induced strains is less than 8.3%, indicating its good temperature stability. The maximum vibration velocity of the ceramic at temperature rise of 20 °C is measured to be 0.92 m/s, which is about 2 times higher than that of commercial hard PZT ceramics, suggesting the BNT- x PMnN-PZ y T ceramic is a competitive and potential candidate for power piezoelectric transduction and actuation applications. [ABSTRACT FROM AUTHOR]

The Demand for circulating cooling water (CCW) with high temperature stability and a quick response to temperature control is essential for precision engineering, so a dynamic thermal filtering method is proposed in this paper. Some CCW is bypassed, blocked, and used as a thermal capacity medium, and the temperature fluctuation of CCW is significantly reduced by heat exchanging with the medium. The temperature of the medium dynamically follows the set value of the CCW temperature by real time updating, and so realizes a quick CCW temperature control response. The attenuation ratio of temperature fluctuation was derived, theoretically validating the effectiveness of the method. The experimental results indicate that a CCW temperature fluctuation attenuation ratio of tens of dB (−3.47 dB, −6.91 dB, −10.97 dB and −15.28 dB corresponding to temperature fluctuation frequencies of 0.01 Hz, 0.025 Hz, 0.053 Hz and 0.105 Hz, respectively) is achieved by the proposed method. The updating time of thermal capacity medium is 82 s, which means that the temperature fluctuation attenuation remains functionally valid when the set value of CCW changes. The proposed method is low cost in operation and provides an effective approach to satisfy the challenging demand for CCW with high stability and a good dynamic temperature control performance. [ABSTRACT FROM AUTHOR]

Ferroelectric (1-x)Sr 0.875 Pb 0.125 TiO 3 -xBi(Mg 0.5 Zr 0.5)O 3 ((1-x)SPT-xBMZ, x = 0-0.2) ceramics with high discharge efficiency and power density were synthesized via a conventional solid-state sintering method. The prepared (1-x)SPT-xBMZ ceramics were detected as a pure perovskite structure and a dense microstructure, and a typical relaxor behavior and an excellent temperature stability were also observed. Although there is no direct correlation between the degree of diffuseness and the maximum polarization, the high degree of diffuseness can reduce the remanent polarization and significantly improve energy storage and release characteristics of ferroelectric ceramics. Based on a polarization electric-field loop measurement, a recoverable energy storage density of 0.762 J/cm3 and a very high efficiency of 96.34% are achieved when x = 0.2 under 150 kV/cm. The energy storage properties of 0.8SPT-0.2BMZ ceramic exhibit good temperature stability (25−130 °C) and frequency stability (2−80 Hz). In a practical charge-discharge circuit testing, a short discharge pulse-period about 94 ns, a high discharge energy density of 1.7 J/cm3 and an ultra-high-power density of 62.8 MW/cm3 are obtained for the 0.8SPT-0.2BMZ ceramic at 240 kV/cm. The results indicate that the 0.8SPT-0.2BMZ ceramic is a promising dielectric material for high-power pulse capacitors. [ABSTRACT FROM AUTHOR]

BiScO 3 -PbTiO 3 ceramics are attractive for high-temperature piezoelectric applications while their high dielectric loss has to be substantially reduced. In this paper, a ternary perovskite system of x Bi(Mn 1/2 Zr 1/2)O 3 -(1- x - y)BiScO 3 - y PbTiO 3 (abbreviated as x BMZ-BS- y PT) with x = 0.02, 0.04 and y = 0.62–0.67 were fabricated by conventional solid-phase method, and their ceramics were systematically studied with regards to phase structure, microstructure, dielectric and piezoelectric properties. X-ray diffraction results indicate a gradual change from rhombohedral to tetragonal phase with increasing PT composition. Morphotropic phase boundary (MPB) is revealed for the system with x = 0.02, y = 0.64, at which ultralow dielectric loss factor (0.58 %), almost unchanged Curie temperature (449 °C), high electromechanical properties (d 33 = 360 pC/N, k p = 0.53), and stable strain output below 200 °C are observed. With such excellent piezoelectric properties and high-temperature stability, BMZ modified BS-PT ceramics are promising candidates for power electromechanical devices, especially operating in high-temperature environments. [ABSTRACT FROM AUTHOR]

A capacitive type MEMS switch with electrostatic control is presented. A movable electrode is made in the form of a beam fixed at both ends. A metal electrode with a floating potential which allows increasing the ratio of the capacities in the on and off states by more than an order of magnitude compared to the classical design is considered a feature of the device. The operating characteristics of the switch are calculated by the finite element method. Aluminum was chosen as the material of the beam and hafnium dioxide serves as the insulator. The design provides an ultrahigh capacitance ratio of up to 7400. The tripping voltage ranges from 7.5 to 58.0 V, depending on the selected geometry. Its speed is at the microsecond level. The disadvantage of the switch lies in the significant deformation of the beam with temperature. Ways to overcome it are proposed. [ABSTRACT FROM AUTHOR]

Thermal stability of capacitors with both superior recoverable energy density (W rec) and efficiency (η) have recently attracted great research interest for application in the pulse power systems. Here, high-quality lead-free relaxor-ferroelectric (RFE) (1-x)Bi 0.5 Na 0.5 TiO 3 -x(Na 0.73 Bi 0.09)NbO 3 [(1-x)BNT–xNBN, x = 0.10–0.18 ] ceramics are fabricated through solid-state reaction method. The NBN substitution of NBT ceramics could improve effecitively breakdown strength (BDS), energy storage performances, and the thermal stability. Especially, excellent recoverable energy density (W rec ~ 2.41 J/cm3) and efficiency (η ~ 81.6%) could be achieved synchronously in 0.84BNT–0.14NBN ceramic. Moreover, the good thermal stability (20 °C ~ 140 °C), frequency stability (1–1000 Hz), and fatigue endurance (104 cycles) are also obtained in the composition of x = 0.14 ceramic. Particularly, corresponding ceramic shows high current density (~ 817 A/cm2), discharge energy density (~ 0.729 J/cm3), extremely short discharge rate (< 50 ns), and power density (~ 49 MW/cm3) from 20 to 140 °C. This research provides a creative method for preparing high-performance capacitors in high-temperature applications. [ABSTRACT FROM AUTHOR]

High‐temperature capacitors have become an important research topic recently as commercially available capacitors cannot fulfill the new requirements from industry. In this work, a new ceramic ternary system (1 − x)[0.9Na0.5Bi0.5TiO3‐0.1BiAlO3]‐xNaNbO3 is introduced, and the effects of NaNbO3 concentration on macroscopic phase structure, locally disordered structure, dielectric properties, conduction properties, and energy storage properties are studied. At the optimum composition of x = 0.30, an ultrawide temperature range (−90 and 320 °C) covering both stable permittivity (Δε′/ε′25°C ≤ ± 15%) and low dielectric loss (tan δ ≤ 0.02) can be obtained. Additionally, this material has a high RC constant of 2.8 s and a high energy storage efficiency of 88% under the electric field of 60 kV cm−1 at room temperature. Therefore, this work provides a very promising candidate for dielectrics used in multilayer ceramic capacitors (MLCC) in an ultrawide operating temperature range. [ABSTRACT FROM AUTHOR]

(K0.48Na0.48Li0.04)(Nb0.8Ta0.2)O3 (KNN-LT) ceramics were prepared by the traditional solid-state reaction method. The combined effects of Li and Ta additions resulted in a decrease in the orthorhombic-tetragonal (TO-T) and Curie temperature (Tc). The piezoelectric and electromechanical properties were found to be d33 ∼ 165 pC/N, kt ∼ 0.438, kp ∼ 0.363 at the sintering temperature 1178 ˚C. It has a wide temperature range for ferroelectric properties and energy storage density and possess a good temperature stability. [ABSTRACT FROM AUTHOR]

Phenylacetone monooxygenase (EC 1.14.13.92, PAMO) catalyzes oxidation of ketones with molecular oxygen and NADPH with the formation of esters. PAMO is a promising enzyme for biotechnological processes. In this work, we generated genetic constructs coding for PAMO from Thermobifida fusca, containing N- or C-terminal His6-tags (PAMO N and PAMO C, respectively), as well as PAMO L with the His6-tag attached to the enzyme C-terminus via a 19-a.a. spacer. All PAMO variants were expressed as catalytically active proteins in Escherichia coli BL21(DE3) cells; however, the expression level of PAMO N was 3 to 5 times higher than for the other two enzymes. The catalytic constants (kcat) of PAMO C and PAMO L were similar to that published for PAMO L produced in a different expression system; the catalytic constant for PAMO N was slightly lower (by 15%). The values of Michaelis constants with NADPH for all PAMO variants were in agreement within the published data for PAMO L (within the experimental error); however, the KM for benzylacetone was several times higher. Thermal inactivation studies and differential scanning calorimetry demonstrated that the thermal stability of PAMO N was 3 to 4 times higher compared to that of the enzymes with the C-terminal His6-tag. [ABSTRACT FROM AUTHOR]

Materials with negative permittivity need to be used at different temperatures, while the negative permittivity behavior affected by large fluctuations in temperature has seldom been studied. In this work, La 0.5 Sr 0.5 MnO 3 ceramics were prepared by a sol-gel auto-combustion method and subsequent sintering. The negative permittivity behavior, electrical conductivity and reactance of La 0.5 Sr 0.5 MnO 3 ceramics were systematically studied at various temperatures. The fluctuation in negative permittivity is less than 2.6 % and the dielectric loss (tan δ) is less than 0.2 in the temperature range of 50–600 °C. Based on the key governing properties being achieved, the present work experimentally demonstrates that La 0.5 Sr 0.5 MnO 3 ceramics, as single-phase oxides, can be used as a feasible alternative metamaterial in a wide temperature range. [ABSTRACT FROM AUTHOR]

High strain and good temperature stability are contradictory properties in (K, Na)NbO3 (KNN)‐based materials. Herein, good temperature stability with high strain is obtained in a multiphase coexistent [ie, orthorhombic‐tetragonal (O‐T) and rhombohedral‐orthorhombic‐tetragonal (R‐O‐T)] KNN. A second‐order transition‐like characteristic should contribute to the temperature stability, in which an intrinsic lattice structure forms a bridge between them. The observed second‐order transition‐like characteristic is due to the reduced discrepancy among different lattice symmetries and a broadened temperature region for the phase transition. These integrated factors can slow the latent heat in a first‐order transition and extend it over a wide temperature region, thereby exhibiting second‐order transition‐like behavior. Correspondingly, the abrupt increase in strain near the phase transition temperature significantly slows. In addition, the appearance of pure tetragonal symmetry (P4mm) is deferred to a much higher temperature than TO‐T, in which the strain will inevitably decrease. As a result, good temperature stability with a high strain response can be realized in multiphase coexistent KNN materials, including d33*=448 pm/V, ‐27.5%≤fluctuation≤4.2% for O‐T, and d33*=446 pm/V, ‐17.5%≤fluctuation≤7.6% for R‐O‐T, over the whole temperature range 25 °C‐190 °C. [ABSTRACT FROM AUTHOR]