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The morphology and structure of sensing materials are extremely important to performances of gas sensor. Zinc oxide (ZnO) is a promising gas-sensing material, due to its morphology controllable fabrication. In this work, flower-like ZnO (FZnO) was synthesized on GaN by electrodeposition as sensing materials of ethanol gas sensor. FZnO consisting of ZnO nanosheets with thickness of 55 nm is in situ grown on GaN. When FZnO/GaN heterojunction is used as sensing materials for detection of ethanol, this material possesses a higher response than ZnO or ZnO composite at room temperature. In detail, the FZnO/GaN based gas sensor displays remarkable sensitivity (Ra/Rg = 26.9), when the sensor is exposed to ethanol at the concentration of 50 ppm at room temperature. Importantly, rapid response and recovery time is 12 and 9 s, respectively. Meanwhile, this sensor presents excellent selectivity and stability. In addition, detection limit of the sensor is 100 ppb. Enhancement of the sensing response is mainly attributed to the FZnO and conductivity of the GaN. These results indicate the potential applications of the as-prepared metal oxide semiconductor based GaN in the sensing field.

Zinc oxide nanorods (ZnO NRs) were grown on gallium nitride (GaN) substrates by electrodeposition. HRTEM and XRD analyses were performed to determine crystalline structure. Single crystal ZnO NRs with an average size of 240 nm were grown along the c-axis direction. The resulting H2S sensors based on ZnO NRs/GaN displayed excellent selectivity and response, particularly in the concentration range of 1–50 ppm of H2S. In the concentration of 50 ppm H2S, a sensing response time of 82 s and a recovery time as low as 48 s can be achieved at 240 °C. In addition to ZnO NRs forming porous network channels for gas diffusion in and out, the H2S-sensing performance of ZnO NRs/GaN heterojunctions could be attributed to the enhanced electron transport and the favorable charge transfer resulting from the excellent transport capability of GaN. The in-situ fabrication of sensing materials makes our sensors extremely attractive in the field of H2S detection.

In conventional magnetometry, exchange bias training (EBT) is mostly evaluated through the major magnetization hysteresis loops (MHLs). We here report a study of EBT by using the first-order reversal curves (FORCs) in the heterostructures of ${\mathrm{SrTiO}}_{3}(001)/{\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{FeO}}_{3}(\mathrm{LSFO})/{\mathrm{Ni}}_{79}{\mathrm{Fe}}_{21}(\mathrm{Py})/{\mathrm{PyO}}_{x}$. It was unraveled that the training effect occurs once after exceeding the left coercivity of the first MHL, while the magnetic coupling from the ultrathin native oxide (${\mathrm{PyO}}_{x}$) mainly contributes to an exchange springlike behavior. Besides for the first MHL, the FORCs corresponding to the second MHL and the quasiequilibrium stage were collected, respectively, which provide a detailed picture of how the magnetization reversal evolves in the training process.

The influence of Ho substitution for Tm atoms on the magnetic properties and magnetocaloric effect (MCE) of TmGa compound was systematically investigated according to magnetic measurements and neutron powder diffraction (NPD) experiments. The magnetic transitions of ${\mathrm{Tm}}_{1\ensuremath{-}x}{\mathrm{Ho}}_{x}\mathrm{Ga}$ compounds show different types by Ho substitution due to the variation of spin and orbital angular momentum quantum number and the complete magnetic diagram of ${\mathrm{Tm}}_{1\ensuremath{-}x}{\mathrm{Ho}}_{x}\mathrm{Ga}$ compounds was obtained. The spin reorientation (SR) transition of ${\mathrm{Tm}}_{0.1}{\mathrm{Ho}}_{0.9}\mathrm{Ga}$ compound was directly confirmed by variable-temperature NPD experiments. Results show that the magnetic moment orders along the $c$ axis at the temperatures between ${T}_{\mathrm{SR}}$ and ${T}_{\mathrm{C}}$ and it cants away from the $c$ axis towards the $ab$ plane upon cooling below ${T}_{\mathrm{SR}}$. Furthermore, Ho substitution plays a dominant role in MCE of ${\mathrm{Tm}}_{1\ensuremath{-}x}{\mathrm{Ho}}_{x}\mathrm{Ga}$ compounds. When $x=0.15$, the peak value of magnetic entropy change reaches the maximum value of 18.0 J/kg K under field change of 0--2 T. The refrigerant temperature span ($\ensuremath{\delta}{T}_{\mathrm{FWHM}}$) and refrigeration capacity of ${\mathrm{Tm}}_{0.85}{\mathrm{Ho}}_{0.15}\mathrm{Ga}$ compound show enhancement of 23.0 and 21.6%, correspondingly, compared with TmGa compound. The giant MCE of ${\mathrm{Tm}}_{0.85}{\mathrm{Ho}}_{0.15}\mathrm{Ga}$ compound results from the optimization of spin and total angular momentum quantum number by Ho substitution.

Amphotericin B (AmB), an effective polyene drug with broad spectrum antifungal activity, is used for serious fungal infections. Liposomal amphotericin B (LAmB) is a lipid dosage form, which has a significantly improved toxicity profile compared with conventional amphotericin B deoxycholate (DAmB). This study focused on verifying the gender differences in the acute toxicity of LAmB and further exploring its causes. Acute toxicity study of LAmB and DAmB were performed in rats, and toxicity responses and mortality of different sexes were observed and recorded. Concentrations of AmB in rat plasma and tissues were determined by a fully validated UPLC-MS/MS assay. The results demonstrated that LAmB showed significant gender differences in acute toxicity, with more severe toxic symptoms and higher mortality for female rats at different doses, but the same differences were not observed for DAmB under the same condition. To explore the cause of differences, toxicokinetic and tissue distribution studies were performed and the results showed that female animals had higher drug exposure, longer half-life and lower plasma clearance compared to male rats, and the drug was mostly distributed in the liver and kidneys, in which female rats displayed a significant higher concentration than that of male rats.

Reduced dimensionality offers a piece of crucial information in deciding the type of the quantum ground state in heavy fermion materials. Here we have examined the stoichiometric ${\mathrm{CeCo}}_{2}{\mathrm{Ga}}_{8}$ compound, which crystallizes in a quasi-one-dimensional crystal structure with Ga-Ce-Co chains along the $c$ axis. The low-temperature behavior of the magnetic susceptibility ($\ensuremath{\chi}\ensuremath{\sim}{T}^{\ensuremath{-}0.2}$), heat capacity (${C}_{p}/T\ensuremath{\sim}\ensuremath{-}lnT$), and resistivity ($\ensuremath{\rho}\ensuremath{\sim}{T}^{n}$ with $n\ensuremath{\sim}1$) strongly confirms the non-Fermi liquid ground state of ${\mathrm{CeCo}}_{2}{\mathrm{Ga}}_{8}$. We study the low-energy spin dynamics of the ${\mathrm{CeCo}}_{2}{\mathrm{Ga}}_{8}$ compound utilizing zero-field (ZF) and longitudinal-field muon spin relaxation ($\ensuremath{\mu}\mathrm{SR}$) measurements. ZF-$\ensuremath{\mu}\mathrm{SR}$ measurement reveals the absence of long-range magnetic ordering down to 70 mK. Interestingly, below 1 K the electronic relaxation rate rises sharply, suggesting the appearance of low-energy quantum spin fluctuations in ${\mathrm{CeCo}}_{2}{\mathrm{Ga}}_{8}$.

The e-skin based on lead zirconate titanate (PZT) exhibits excellent electrical sensing performance, and it is widely used in clinical trials owing to its prominent piezoelectric, ferroelectric and pyroelectric performance. However, the complicated fabrication procedure and fatigue during long-term use still limit its application. In this study, a flexible e-skin withstanding fatigue over extended periods of use (more than 10 000 cycles) was facilely constructed by combining polydimethylsiloxane (PDMS) with a highly crystalline PZT thin film. Note that the sensor was first fabricated using the micro-structured PZT thin film via a low-temperature pulsed laser deposition system (PLD) method, which could be easily combined with other processes. The sensor highlighted an ultra-high detection sensitivity (S, ∼5.82 kPa−1) and almost negligible hysteresis rate or degree of hysteresis (DH, ∼0.45%) in the pressure-sensing test. Moreover, the obtained sensor exhibited the lower limit of detection (LOD) of 30 Pa as well as a faster response (∼0.38 s) and release time (∼0.79 s). Importantly, due to the excellent performance of this sensor, various dynamic and static signals of the human body could be detected within the maximum range allowed under the septal fracture effect.

Flexible piezoresistive sensors with high sensitivity and repeatability are highly desirable for monitoring human activity and human–machine interactions. However, it is still a great challenge to fabricate high-performance sensors due to the limits of multifunctional sensing platforms. In this work, hierarchical framework-structured PVDF/PU/MWCNT (PPM) aerogels fabricated by a facile thermo-assembly method were suggested as sensitive sensing platform to detect pressure and strain. The pressure-sensing platform based on optimized PPM aerogels exhibited high sensitivity of 62.4 kPa−1 and fast response of 35 ms, which enabled the detection of minute static pressure of 3 Pa. The sensing platform was also able to detect wide-range compression from 0.5% to 90% and dynamic piezoresistive response behaviour from 1 Hz to 3 kHz, showing excellent repeatability over 50 000 compression cycles and ultrahigh strain sensitivity of 156.4, which was the highest reported gauge factor. Moreover, the sensing platform with ultrahigh sensitivity and excellent repeatability enabled the monitoring of human activities, human health, human–machine interactions and non-contact actions such as music intensity. The facile fabrication and versatile capabilities of the sensing platform make it a promising candidate for wearable sensors.

A composite prepared from zinc oxide and graphene oxide nanoribbons (ZnO/GONR) is demonstrated to enable improved room temperature (RT) detection of nitrogen dioxide (NO2). Low-cost hydrothermal synthesis is used to construct the composite. The properties of the resistive sensor, including the sensitivity, response and recovery times, repeatability and selectivity, were investigated in the NO2 concentration range from 1 to 50 ppm at RT. The sensor, typically operated at a voltage of 5 V, exhibits a low detection limit of 1 ppm, a fast response–recovery time, and excellent repeatability which outperforms that of pure ZnO sensors. The sensing mechanism is explained in terms of a redox reaction between NO2 and oxygen anions on the surface of the ZnO/GONR composite.

High-efficiency and environment-friendly magnetic refrigeration, as a replacement to conventional gas compression, has drawn increasing attention. In this article, polycrystalline TmCoSi and TmCuSi compounds were successfully synthesized and giant low field magnetocaloric effect (MCE) was investigated. Under field change of 0–1 T, (-ΔSM)max of 12.0 J/kg K and 8.7 J/kg K and (ΔTad)max of 6.2 K and 3.7 K were obtained at low temperatures for TmCoSi and TmCuSi compounds, respectively. It could be considered as one of the best low-temperature MCE materials compared with reported ErMn2Si2 compound showing (-ΔSM)max and (ΔTad)max of 14.7 J/kg K and 2.5 K respectively. Furthermore, a low-field and reversible giant MCE around the boiling point of liquid helium with the negligible thermal and magnetic hysteresis indicates that TmCuSi and TmCoSi compounds could be potential candidates of magnetic refrigeration for liquid helium temperature region.

A composite prepared from zinc oxide and graphene oxide nanoribbons (ZnO/GONR) is demonstrated to enable improved room temperature (RT) detection of nitrogen dioxide (NO

We report an investigation of Raman spectroscopy of the mixed-phase ${\mathrm{BiFeO}}_{3}$ film grown onto ${\mathrm{LaAlO}}_{3}$(001) by ${90}^{\ensuremath{\circ}}$ off-axis magnetron sputtering. The polarized Raman spectra unveil different sets of phonon vibrations, which can be assigned to the modes of the tetragonal($T$)-like polymorph, the rhombohedral($R$)-like polymorph, and the bridging phase (${S}_{\mathrm{tilt}}^{\ensuremath{'}}$ and ${T}_{\mathrm{tilt}}^{\ensuremath{'}}$) in between. Furthermore, the unpolarized Raman scattering as function of temperature unravels multiple anomalies in the phonon behavior of the $T$-like phase not only at its multiferroic transition ($\ensuremath{\sim}370\phantom{\rule{0.16em}{0ex}}\mathrm{K}$) but also at the Polomska transition ($\ensuremath{\sim}450\phantom{\rule{0.16em}{0ex}}\mathrm{K}$) and the antiferromagnetic transition of the $R$-like phase ($\ensuremath{\sim}640\phantom{\rule{0.16em}{0ex}}\mathrm{K}$). The unusual phonon behavior indicates the presence of spin-phonon coupling and also long-ranged strain coupling between the $T$-like and $R$-like polymorphs, which provides new insights into hybrid systems at the morphotropic phase boundaries.

A heterojunction of ZnO/porous GaN (ZnO/PGAN) was fabricated and directly applied to a diode-type humidity sensor. ZnO disks were loaded onto PGAN using a spraying process. The structure and surface morphology of the ZnO/PGAN were characterized using X-ray diffraction and scanning electron microscopy. The heterojunction displayed an excellent diode nature, which was investigated using photoluminescence spectra and I–V characteristics. The excellent transport capability of ZnO/PGAN contributes to enhanced electron transfer, and hence results in high sensitivity and quick response/recovery properties under different relative humidity (RH) levels. In the range of 12–96% RH, a fast sensing response time as low as 7 s and a recovery time of 13 s can be achieved. The simple design of a ZnO/PGAN based humidity sensor highlights its potential in various applications.

We use time-domain terahertz spectroscopy to measure the low energy conductivity and magnons in RuCl$_3$ under external magnetic field. At zero field, an oscillation with a frequency of 0.62 THz is clearly observed in time-domain spectrum below T$_N$, which is identified as a magnon excitation in the magnetic order state. The magnon excitation is not affected by the external magnetic field $\textbf{H}_{DC}$ when it is applied along the c-axis, but is clearly suppressed when $\textbf{H}_{DC}$ is applied within ab plane. More interestingly, when the magnetic component of THz wave $\textbf{h}(t)$ is perpendicular to the applied in-plane magnetic field, we observe another coherent oscillation at slightly higher energy scale at the field above 2 T, which is eventually suppressed for $H_{DC}>$5 T. The measurement seems to indicate that the in-plane magnetic field can lift the degeneracy of two branches of low energy magnons at $\Gamma$ point. The low energy optical conductivity calculated from the measured transmission spectrum is dominated by a broad continuum contribution, which is not affected by changing either temperature or external magnetic field. The continuum is likely to be related to the fractional spin excitation due to dominated Kitaev interaction in the material., Comment: 6 pages

Magnetic properties and magnetocaloric effect (MCE) of HoCu0.33Ge2 and ErCu0.25Ge2 compounds have been investigated. The compounds were determined to be antiferromagnetic with the Neel temperatures T-N = 9 K and 3.9 K, respectively. The critical transition magnetic fields for the metamagnetic transition from antiferromagnetic to ferromagnetic state below T-N were determined to be 10 kOe for HoCu0.33Ge2 at 5 K and 6 kOe for ErCu0.25Ge2 at 2 K. Large MCE with the maximal values of magnetic entropy changes (Delta S-M) as -10.2 J/kg K at 10.5 K were found in HoCu0.33Ge2 for field changes of 0-70 kOe and -10.5 J/kg K at 5.5 K in ErCu0.25Ge2 for field changes of 0-50 kOe, respectively. The large Delta S-M around T-N as well as no hysteresis loss made RCuxGe2 competitive candidates as low temperature magnetic refrigerant. (C) 2015 Elsevier B.V. All rights reserved.

The magnetic properties and magnetocaloric effect of Cu doping on HoNiAl (HoNi 1 − x Cu x Al) have been investigated. Two transitions occurred for samples with x = 0 and x = 0.1 induced by the combination and competition between antiferromagnetic (AFM) and ferromagnetic (FM) orderings. Simple AFM orderings were found in samples with x = 0.2 to x = 0.7 while FM orderings were found in samples with x = 0.8–1. The magnetocaloric effect (MCE) was investigated in selected samples with x = 0.3 and 0.8. Large magnetic entropy changes (Δ S M ) as −29.2 J/kg K at 9 K and −19.7 J/kg K at 9 K with corresponding refrigerant capacity (RC) of 299 J/kg, 309 J/kg for a field change of 0–50 kOe were observed. The large Δ S M and RC without hysteresis loss indicated these materials attractive candidates for magnetic refrigeration in low temperature range.

Magnetic properties and magnetocaloric effect (MCE) of the CeSi compound are investigated. The compound is determined to be antiferromagnet with the Neel temperature T-N = 6.1 K. A metamagnetic transition from antiferromagnetic (AFM) to ferromagnetic (FM) state occurs at 2 K under an applied magnetic field of 4 kOe. Field variation generates a large MCE and no magnetic hysteresis loss is observed. The maximum values of magnetic entropy change (Delta S) are found to be -7.2 J/kg K and -13.7 J/kg K for the field changes of 0-20 kOe and 0-50 kOe, respectively. The large Delta S with no hysteresis loss as well as low price of crude materials make CeSi a competitive candidate for low temperature magnetic refrigerant. In addition, the unusual magnetism in CeSi can be attributed to the appearance of a quartet ground state. (C) 2013 Elsevier B.V. All rights reserved.

The effects of mechanical alloying on the solubility in a Ag-Gd solid solution have been investigated. The study shows that the solubility of Gd in Ag can be extended to about 5 at. % Gd by mechanical alloying from the equilibrium solubility of less than 0.95 at. % Gd. ${\mathrm{Ag}}_{85}$${\mathrm{Gd}}_{15}$ prepared by mechanical alloying exhibits a spin-glass-type transition at \ensuremath{\sim}5 K. A Curie-Weiss behavior at higher temperatures and x-ray patterns of the material indicate that Gd atoms are either dissolved in the Ag matrix or in the form of small clusters of diameters of a few nanometers.