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A magnetoelectric (ME) D-FF device in composite of Ni-Zn ferrite/PZT/ Ni-Zn ferrite symmetrical laminate with coil wound around it has been presented. Taking advantage of remnant magnetization effect and ME coupling mediated by strain controlled by bias magnetic field, non-volatile ME voltage of + 60.3 mV and − 59.4 mV can be clearly observed at the EMR of 58 kHz in absence of HDC. Moreover, two types of ME voltages between + 234.4 mV and − 233 mV are switched due to the magneto-mechanic strain variation, when HDC jumps from + 38 Oe to − 38 Oe, or vice versa. The functions of logic “tracking” and “holding”, On+1 = D1 or On+1 = On, are observed at running time. These findings provide great possibilities of the D-FF (counter) based on ME composite applied in proximity readers, to effectively avoid the issues of the high consumption due to using conventional D-FF/counter.

The purpose of this study was to identify the fractal dimension and their relationships with alkalinity properties of soils, and to evaluate the potential of fractal dimension as an indicator of alkalinity properties of soil. Six soils with an increasing salinity (electrical conductivity was 0.09, 0.18, 0.62, 0.78, 1.57 and 1.99 dS m−1, respectively) were selected from the western part of the Songnen Plain (China). Salt content, exchangeable sodium percentage, sodium adsorption ratio and other properties of the soils were determined and the soil particle-size distribution (0–2000 μm) was measured using a laser diffraction particle size analyser. Our results show that the overall fractal dimension of the selected soils ranged from 2.35 to 2.60. A linear regression analysis showed a significant negative correlation between fractal dimension and the amount of coarse sand and fine sand (r = − 0.5452, P P P P P 3− (P

A theory of the magnetoelectric effect in three-layer asymmetric structures composed of a piezoelectric layer and two magnetostriction layers with opposite magnetostriction signs is presented. The thickness ratio of the layers is obtained, at which this effect is maximum. It is shown that the sign of the magnetoelectric coefficient changes to opposite (with respect to the initial two-layer structure) with an increase in the third-layer thickness. It is established that the magnetoelectric coefficients of the structures with different arrangements of the layers with positive and negative magnetostriction have opposite signs.

This report is on the synthesis by electrospinning of multiferroic core-shell nanofibers of strontium hexaferrite and lead zirconate titanate or barium titanate and studies on magneto-electric (ME) coupling. Fibers with well-defined core–shell structures showed the order parameters in agreement with values for nanostructures. The strength of ME coupling measured by the magnetic field-induced polarization showed the fractional change in the remnant polarization as high as 21%. The ME voltage coefficient in H-assembled films showed the strong ME response for the zero magnetic bias field. Follow-up studies and potential avenues for enhancing the strength of ME coupling in the core–shell nanofibers are discussed.

Qinghai-Tibet plateau as an alpine and high-altitude area is frequently confronted with freeze-thaw stress. Recently, due to the change of global climate, the drought and salinization of soil in this area have become increasingly serious, together with low temperature, and constitute the main limiting factors for crop growth in this area. Physiological responses of blue barley to salinization (S), drought (D), and freeze-thaw (F) stress were studied. Through applying 100 mmol/L NaCl, 15% drought and freeze-thaw cycle (10, − 5, 10 °C) stress, the changes of relative water content (RWC), soluble protein, malondialdehyde (MDA), superoxide dismutase (SOD), and peroxidase (POD) in seedling leaves of 8 treatment groups (CK, S, D, DS, F, FD, FS, and FDS) were analyzed. The results showed that single stress, either NaCl, drought, or freeze-thaw, could lead to the decrease of RWC and the increase of not only the soluble protein and MDA content, but also the SOD and POD activity in leaves. During the freeze-thaw cycle, the soluble protein, MDA content, SOD, and POD activity of seedlings increased at first and gradually decreased, while RWC gradually decreased with the change of temperature. The research indicated that there were synergistic effects among the stresses of drought, NaCl, and freeze-thaw on the plant, and the compound stress could cause more serious effect on the plant compared with the single one.

Nanofibers of Y- or W-type hexagonal ferrites and core–shell fibers of hexagonal ferrites and ferroelectric lead zirconate titanate (PZT) or barium titanate (BTO) were synthesized by electrospinning. The fibers were found to be free of impurity phases, and the core–shell structure was confirmed by electron and scanning probe microscopy. The values of magnetization of pure hexagonal ferrite fibers compared well with bulk ferrite values. The coaxial fibers showed good ferroelectric polarization, with a maximum value of 0.85 μC/cm2 and 2.44 μC/cm2 for fibers with BTO core–Co2W shell and PZT core–Ni2Y shell structures, respectively. The magnetization, however, was much smaller than that for bulk hexaferrites. Magneto-electric (ME) coupling strength was characterized by measuring the ME voltage coefficient (MEVC) for magnetic field-assembled films of coaxial fibers. Among the fibers with Y-type, films with Zn2Y showed a higher MEVC than films with Ni2Y, and fibers with Co2W had a higher MEVC than that of those with Zn2W. The highest MEVC of 20.3 mV/cm Oe was measured for Co2W–PZT fibers. A very large ME response was measured in all of the films, even in the absence of an external magnetic bias field. The fibers studied here have the potential for use in magnetic sensors and high-frequency device applications.

A model for the low-frequency magnetoelectric (ME) effect that takes into consideration the bending deformation in a ferromagnetic and ferroelectric bilayer is presented. Past models, in general, ignored the influence of bending deformation. Based on the solution of the equations of the elastic theory and electrostatics, expressions for the ME voltage coefficients (MEVCs) and ME sensitivity coefficients (MESCs) in terms of the physical parameters of the materials and the geometric characteristic of the structure were obtained. Contributions from both bending and planar deformations were considered. The theory was applied to composites of PZT and Ni with negative magnetostriction, and Permendur, or Metglas, both with positive magnetostriction. Estimates of MEVCs and MESCs indicate that the contribution from bending deformation is significant but smaller than the contribution from planar deformations, leading to a reduction in the net ME coefficients in all the three bilayer systems.

Electric-field-controlled resonance tuning in tri-layer magnetoelectric laminate consisting of Ni–Zn ferrites (with/without Sm-doped) and PZT plates has been performed and systemically characterized. By applying the DC voltage on PZT plate, modulus of the sample will change in ferrite which is caused by mediated pre-stress from PZT plate, resulting in a resonance shifting without a sacrifice of MEVC decay. For the purpose of tuning range improvement, light doping of samarium was employed in spinel nickel–zinc ferrites to modify frequency responses properties. Experimental results showed that a nearly linear variation of resonance frequency with applied voltage varied from 0 to 6 kV/cm was obtained. Consequently, the resonance frequency can be precisely controlled by the pre-stress generated from DC electric field. In addition, the tunability of resonance frequency exhibits an approximately 3.68 times enhancement by samarium doping in the Ni–Zn ferrites. The pathway for resonance frequency tunable realization by applied DC voltage provides an accurate tuning method for the tunable resonator, which can be deployed extensively in signal generators, phase shifters and other electronic devices.

According to the principle of metal-enhanced fluorescence (MEF), a localized surface plasmon resonance (LSPR) based method was used to develop a highly sensitive fluorescent aptasensor for detecting adenosine triphosphate (ATP). In this work, a polyAn-based special nucleic acid aptamers modified on gold nanoparticle (AuNPs) were hybridized with the FAM-labeled single-stand oligonucleotides. It was found that a great enhancement of fluorescence intensity in the nanostructures could be programmable regulated by adjusting the number of base A. The experiments showed the maximum enhancement for the fluorophore occurs when the polyAn length reached to 9 nm and, there was a good linear relationship between the fluorescence intensity and concentrations of ATP in the range of 0.5–1 nM. The detection limit obtained was 0.2 nM. Compared with the detection performances of traditional strategies, the sensitivity of the method was increased by more than 7 times, which make it hold great potential in bioanalytical and biological studies.

Low-frequency/resonance magnetoelectric interactions and power conversion efficiency of magnetoelectric gyrators consisting of compositionally-graded nickel zinc ferrites and lead zirconate titanate with a coil wound around it were proposed and systematically characterized. Grading-induced differences of magnetic moment and remnant magnetization in ferrites with composition of Ni1−xZnxFe2O4 (0 ≤ x ≤ 0.3) can create the desired built-in field to decrease the required bias. The samples were characterized in terms of magnetostriction, low-frequency/resonance and power conversion efficiency with varieties of Zn concentrations, reversal sequence and volume ratio. A maximum PE of 62.9% was achieved in the composite of PZT-NiFe2O4-Ni0.9Zn0.1Fe2O4 at H = 10 Oe with volume ratio n = 0.5 under load RL = 700 Ω. With contribution of the desired built-in field, maximum PE of 60% under zero bias was also achieved in similar conditions. These favorable features open up the possibilities of ME gyrators with grading for promising applications in power electronics, converters and wireless energy harvesters without a sacrifice in device volume and modest rise in magnetomechanical efficiency.

This report is on the observation and theory of electric field E induced non-linear magnetoelectric (NLME) effects in single crystal platelets of ferrimagnetic M-type strontium aluminum hexagonal ferrite. Using microwave measurement techniques, it was found that a DC electric field along the hexagonal c-axis results in significant changes in the saturation magnetization and uniaxial magneto-crystalline anisotropy field and these changes are proportional to the square of the applied static electric field. The NLME effects were present with or without an external bias magnetic field. The E-induced variation in magnetic order parameters is attributed to weakening of magnetic exchange and spin–orbit interactions since conduction electrons in the ferrite are effectively excluded from both interactions while being in transit from one Fe ion to another. We present a phenomenological theory which considers magneto-bielectric effects characterized by a quadratic term in electric field E in the free energy density. The coefficients for the NLME coupling terms have been calculated from experimental data and they do show variations with the Al substitution level and the largest rates of change of the saturation magnetization and anisotropy constant change with the applied power were observed for x = 0.4. It was also clear from the study that strength of the NLME effect does not depend on the amount Al substitution, but critically depends on the electrical conductivity of the sample with the highest NLME coefficients estimated for the sample with the highest conductivity. Results of this work are of importance for a new family of electric field tunable, miniature, high frequency ferrite devices.

As a new display technology, electrowetting display (EWD) has many excellent display characteristics, such as paper-like, low power consumption, quick response and full color. These characteristics make EWD devices very suitable for portable devices. However, the gray-scale distortion caused by the contact angle hysteresis of EWDs seriously affects the accuracy of gray-scale display. To improve this phenomenon, the hysteresis curve of an EWD panel was studied according to the motion characteristics of advancing contact angle and receding contact angle of oil in a pixel. Then, a driving scheme for EWDs using alternating current (AC) voltage instead of direct current (DC) voltage was proposed in this paper. And the advantages and disadvantages of the driving scheme at different AC frequencies from 90 to 2,700 Hz were analyzed through experiments. According to the stability of aperture ratio in EWDs, a 470 Hz AC driving scheme was determined. Experimental results showed that the aperture ratio distortion of EWDs could be reduced from 35.82 to 5.97%, which significantly improved the display performance of pixel units.

With the rapid development of society and the economy, the demand for water resources is increasing. This, combined with the increasing competition for water resources between current and future generations, hinders the sustainable development of society. To alleviate prominent water resources problems, achieve sustainable utilization of water resources and the sustainable development of society and economy, a multi-objective optimal water resources allocation model is proposed, in which different water sources and different water departments are considered to achieve the maximum social and economic benefits of the study area on the premise of water resources sustainability. To meet the needs of future generations, the discount value is introduced to measure intergenerational equity. A case study from seven cities in the upper and middle reaches of the Huaihe River Basin is given to verify the practicality and viability of the model. The non-dominated sorting Genetic Algorithms-2(NSGA-2) was used to find optimal water resources allocation schemes in 2020 and 2050 under the condition of a hydrological drought year (inflow guarantee rate p = 75%). Compared with previous models, the intergenerational equity model considers the sustainability of water resources, has higher social and economic benefits, and ensures the fair distribution of water resources among generations. According to the results, under balanced weight, the water shortage ratio of the seven cities will decrease from 5.24% in 2050 to 1.58% in 2020, and the economic benefit will increase from 79.46(1010CNY) to 168.3(1010CNY), respectively. In addition, the discount value of economic benefit in 2050 is 80.23(1010CNY), which is still higher than that in 2020. This shows that the water resource allocation scheme can eliminate the disparity between supply and demand for water resources and achieve intergenerational equity. Therefore, the intergenerational equity model can alleviate the contradiction of water resources and realize intergenerational equity.

A Magneto-Electric (ME) gyrator with a superior power efficiency of 95 % has been achieved based on a two-phase solid-state ME laminate. This ME gyrator consists of a winding coil that generates a magnetic field as the first step to realize electromagnetic energy transfer. A magneto-electric composite, serving as the second step, then converts the power from magnetic to electric forms. The laminate consists of two iron-cobalt based amorphous alloy layers bonded to a lead zirconate titanate plate. It has a giant magneto-electric coefficient of around 2200 (V/cm)/Oe at its mechanical resonant frequency (≈ 44 kHz) in structure. Approaching methods based on maximum power transfer (MPT) efficiency theory and the equivalent loss factor (ELF) from the input port have been introduced to evaluate the power efficiency of the ME gyrator. The expected MPT efficiency is 96.5 % at a power volume density of 0.1 W/in3 (6.1 mWatt/cm3), and 93.2 % up to 20 W/in3 (1.22 W/cm3). The ELF explains that the magnetomechanical conversion efficiency is related to the volume of the magnetic phase which is the dominating term in the power efficiency.

We propose a new method for determining the magnetostriction characteristics of composite multiferroics by measuring the magnetoelectric (ME) response of the material structure. It is established that the integral characteristic of the ME effect coincides to within a constant factor with the magnetostriction curve. The results of an experimental investigation of the physical properties of volume composites based on lead zirconate titanate (PZT) and nickel ferrite spinel are presented. The field dependence of the ME voltage coefficient was used to determine magnetostriction curves of composite structures containing 10–70 wt % ferrospinel.

The growing importance of hydrogels in translational medicine has stimulated the development of top-down fabrication methods, yet often these methods lack the capabilities to generate the complex matrix architectures observed in biology. Here we show that temporally varying electrical signals can cue a self-assembling polysaccharide to controllably form a hydrogel with complex internal patterns. Evidence from theory and experiment indicate that internal structure emerges through a subtle interplay between the electrical current that triggers self-assembly and the electrical potential (or electric field) that recruits and appears to orient the polysaccharide chains at the growing gel front. These studies demonstrate that short sequences (minutes) of low-power (∼1 V) electrical inputs can provide the program to guide self-assembly that yields hydrogels with stable, complex, and spatially varying structure and properties.

A high-Q magnetoelectric (ME) gyrator consisting of a trilayer laminate of nickel-iron-based constant elasticity alloy (Ni–Fe–Cr) and lead zirconate titanate with a coil wound around it has been developed and systematically characterized. Highly efficient magneto-mechanical-electric conversion can be achieved by means of the combination contributions of high quality factors from individuals, and much energy can be transferred through the gyration device. Under an electromechanical resonance frequency of 54.04 kHz, experimental results show that maximum efficiency reaches as high as 88.5% under an extremely low input density of 3.31 µW/cm3 with an optimum load resistance of 9.6 kΩ and a magnetic bias of 66 Oe. Such a highly efficient ME gyrator with a high Q factor can be beneficial or degrade the design goals that are likely to be achievable for practical applications in compact power transfer electronic devices.

We present the first results for resolving methane (CH_{4}) line transition frequencies down to the kilohertz level for overlapping lines using comb-linked cavity ring-down spectroscopy, while most available laboratory measurements, having resolution at the megahertz level, cannot separate merged lines. To demonstrate the technique, Lamb-dip spectra and linear-absorption spectra were used to identify overlapped lines of vibration-rotation spectra in the R9 multiplet of the 2v_{3} band. Three new weak lines were found for the first time. The experimental methods are extensible to other important bands of CH_{4} and many other gas-phase molecules, and should provide a more detailed understanding of molecular structure and line parameters for future high-precision studies.

To precisely position the main energy dissipation sources in ferrite/piezoelectric ME-coil gyrators, the dynamic magneto-mechanical-electric conversion process was disentangled quantitatively by employing a non-contact optical measurement methodology. For the sample fabrication, successful crystallization as well as desired magnetic properties for sintered spinel ferrites was confirmed by XRD and SQUIDs measurements. Trapped magnetic energies in ferrites will convert into kinetic energies accompanying indispensable dissipations in this dynamic process, and the converted kinetic energies can be measured quantitatively in the form of vibrating velocity by focused laser beam. As a result, only ~71% of mechanical energies can be transferred successfully to next layer due to the influence of adhesive in tri-layer sample while the value is 57% for bi-layer one. Finally, comparative studies of low-frequency/resonance ME interactions and power conversion efficiency in tri-layer and bi-layer samples were measured, and an eventual maximum PE of 80.3% under optimum load of 3.5 kΩ was achieved. We infer from the results that the mechanical loss between layers is still a bottleneck to block the efficient energy transfer. These findings provide a deep analysis to reveal the dynamic energy transfer in ME-coil gyrators as well as a flexible pathway for ME gyrators design.

A dielectric AC magnetic sensor in layered ferrites/piezoelectric composites was fabricated and developed, whereby its high magnetodielectric (MDE) effects, the typical magnetic-sensing parameters, were systematically characterized at zero bias. Polycrystalline ferrites were synthesized by the solid-state sintering technique with a composition of Ni0.7Zn0.3Tb0.02Fe1.98O4, and the desired spinel structure and soft magnetic properties were confirmed by x-ray diffraction and VSM, respectively. The field-induced charge order insulating state in piezoelectric ceramics accounts for the suppressed permittivity, which enables the possibility of a highly sensitive magnetic sensor at zero bias field. Experimental results exhibit that a small variation in H as low as 100 mOe can be clearly distinguished with a favorable nonlinearity of 2.24%. Meanwhile, the output stability of the presented sensor under 2h of constant and continuous excitation was tested within a favorable fluctuating tolerance range of 6.14-6.28 nF, and the estimated uncertainty of ∼0.063 038 nF was verified by statistical analysis. The presented ferrite/piezoelectric magnetic sensors exhibiting a high MDE response without the requirement for an external magnetic bias are of importance for use in bio-magnetic field detection due to metrics of miniaturization, high sensitivity, and favorable stabilities.

Epitaxial Ni films with various thicknesses were grown on (0 0 1)-oriented 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN–PT) substrates. Electric field tuning (E-tuning) of ferromagnetic resonance field (Hr) was utilized to investigate the magnetic response of Ni films along different film directions. Butterfly-like Hr vs E curves are shown when magnetic field is applied along film edge. While the combination of both loop-like and butterfly-like Hr vs E curves are observed for Ni film with thicknesses of 180 nm and 240 nm, and merely loop-like curves can be seen for film thicknesses of 330 nm and 510 nm, as magnetic field is applied along film diagonal. These interesting phenomena are assumed to be related to ferroelectric and ferroelastic domain switching in PMN-PT, film strain status, as well as magnetic anisotropy in Ni film. This work demonstrates the feasibility of control of anisotropic magnetic response via electric field in multiferroic heterostructure.

A compact, efficient, and passive magnetoelectric (ME) gyrator consisting of a toroidal ferrite/piezoelectric composite and coil was developed, and its non-reciprocal V–I/I–V and bidirectional impedance conversion properties were systemically characterized. When a maximum V/I coefficient of 115 V/A over RL > 10 kΩ was obtained for the direct ME effect configuration, the output power reaches its maximum of 2.59 μW for optimum RL = 65 Ω at a constant input density of 48.4 μW/cm3, and when an inverse I/V coefficient was obtained, the output power reaches its maximum at 1.4 mA/V and 0.83 μW under optimum RL = 260 Ω and a constant input of 32.3 μW/cm3. Correspondingly, resistance-controlled capacitive/inductance tunabilities of 31 pF/Ω and 0.37 μH/Ω were achieved. Compared to traditional rectangular ME gyrators, the toroidal one has desired electromagnetic interference (EMI) tolerances due to its lower shape-induced anisotropy, near-zero demagnetization effects, and closed magnetic circuit. These findings provided more flexibility of the device design for efficient and compact power electronics deployed in circumstances where the lower EMI at higher frequencies was required.

In regards to the list of authors on this article[1], the names should appear as follows: Y. Liu, P. Zhou, J. Fu, M. Iyengar, N. Liu, P. Du, Y. Xiong, V. Moiseienko, W. Zhang, J. Zhang, Z. Ma, Y. Qi, V. Novosad, T. Zhou, D. Filippov, T. Zhang, M. R. Page and G. Srinivasan

This paper presented a passive current sensor in an electric power grid. The sensor consists of an iron–nickel-based ferromagnetic invariant elastic alloy (FIEA) beam with high quality factor ( $Q$ -factor), piezoelectric ceramic Pb(Zr,Ti)O3 (PZT8), and a Permalloy yoke. The beam bends in the magnetic field of a current-carrying wire as a result of the magnetostriction of the FIEA, and the PZT8 produces a voltage proportional to the electric current in the wire. The electric current sensitivity is potentially improved due to the high $Q$ -factor of the FIEA/PZT8 beam and the concentration effect of the Permalloy yoke. Experimental data are taken to evaluate the feasibility of the current sensor. At the power frequency of 50 Hz, the sensor shows the linear sensitivities of 300.5, 177.9, 119.2, and 88.8 mV/A from 0.2 to 5 A when the separating distances are 6, 10, 15, and 20 mm, respectively. The performances indicate that the proposed device is promising for power-frequency current sensing applications.

The magnetoelectric (ME) effect has been successfully demonstrated in the potential device applications of energy harvesters, magnetic sensors, current sensors, microwave and millimeter-wave multiferroic devices, miniature antennas, and even medical applications. To further investigate the role of ME effect in rotational parameters detection, this paper presents an ME rotational parameter sensor consisting of a magnetostrictive/piezoelectric laminated composite (MPLC) and a multi-pole magnetic ring. The relationship between the proposed sensor’s output signal and the rotational parameters has been analyzed. The output frequency is directly proportional to the rotational speed, and the waveform has a good sin property. In a word, based on the proposed sensor, the rotational speed can be measured by determining the frequency of the output signal, and the rotational position can be detected by the phase discrimination. As the MPLC has the characteristics of high sensitivity and quick response, the starting and stopping times and the eccentricity of rotating pieces can also be measured by the proposed ME rotational parameter sensor.

A non-resonant magnetoelectric (ME) energy converter is presented for scavenging power-frequency magnetic field energy from two-wire power cords. The device is composed of a Terfenol-D/Pb(Mg1/3Nb2/3)O3-PbTiO3(PMNT)/Terfenol-D ME transducer, a NdFeB manget, and E-shaped magnetic yokes. The ME transducer, the magnet, and the magnetic yokes constitute a magnetic circuit, and the bias magnetic field of the ME transducer can be tuned by adjusting the contact area between the magnet and the magnetic yokes to obtain optimal power output. Meanwhile, the power-frequency magnetic field of the power cord is concentrated to the ME transducer by the magnetic yokes, which can potentially improve the power output of the device. Experiments were undertaken to evaluate the potential of energy scavenging from nearby power cords. When coupled to an appliance power cord carrying a current of 16 A, the device generated a rms voltage of 2.46 V and a maximum power of $6.05 \times 10^{\mathrm {-6}}$ W with a matching load resistance of $\sim 1~\text{M}\Omega $ . At a duration of 205 ms, the device can supply power for a temperature-humidity wireless sensor through an up-conversion management circuit with the power consumption of 90 mW at transmitting and 18 mW at receiving.

We introduce an imaging technique, the reciprocity gap (RG) method, for target detection for the borehole geo-radar. The RG method is based on the linear sampling method which has been studied extensively in the mathematical community recently. Based on the RG method, we propose a modified reciprocity gap (MRG) method. As the RG method, the MRG method makes no particular assumptions of buried targets. The technique is fast since it only involves the solution of ill-posed linear integral equations. Moreover, the MRG uses an approximate homogeneous background, Green’s function, when the background medium is inhomogeneous (or unknown) in the measurement domain. Synthetic examples are given to show the performance of the RG method and the MRG method.

A three-dimensional vibration energy harvester employing a magneto-electric (ME) transducer was developed for wireless sensor networks. It uses a magnetic levitation unit to convert ambient vibration in arbitrary directions into the motion of a central suspended magnet. The ME transducer generates output power in response to magnetic field variations. Experiments verify the feasibility of the device. For a vertical acceleration of 0.8 g, the harvester has a bandwidth of 1.9 Hz and a maximum power of 514.5 μW. The average output power varies with the angle between the acceleration and the horizontal plane. The average output power varies from 386.1 to 495.4 μW when the exciting angle increases from 30° to 60°.

Pressure induced conformational and phase transformations of 1,4-dioxane has been investigated up to 37.6 GPa using Raman spectra. Three solid high pressure phases are identified during compression by the observation of markedly different Raman patterns as well as different pressure dependences of characteristic Raman modes. At 1.3 GPa, the liquid 1,4-dioxane finally transforms to solid phase I. Subsequent increasing pressure to 11.4 GPa, the second solid phase presents marked as solid phase II. Above 33.8 GPa, another high pressure structure, solid phase III, is identified. In addition, the influence of high pressure on conformational behavior of 1,4-dioxane has also been discussed. The results show the chair conformer exists in all state of 1,4-dioxane, no matter liquid or solid phase. But 1,4 twist-boat conformation only presents in solid phase I and phase III, while 2,5 twist-boat conformation just exists in solid phase II. Moreover, the formation of hydrogen bond-like C–H⋯O interactions and its response to the extreme condition are also confirmed. Finally, the phase transitions under high pressure are reversible.

The mechanical properties of the cellular nucleus are extensively studied as they play a critical role in important processes, such as cell migration, gene transcription, and stem cell differentiation. While the mechanical properties of the isolated nucleus have been tested, there is a lack of measurements about the mechanical behavior of the nucleus within intact cells and specifically about the interplay of internal nuclear components with the intracellular microenvironment, because current testing methods are based on contact and only allow studying the nucleus after isolation from a cell or disruption of cytoskeleton. Here, all-optical Brillouin microscopy and 3D chemomechanical modeling are used to investigate the regulation of nuclear mechanics in physiological conditions. It is observed that the nuclear modulus can be modulated by epigenetic regulation targeting internal nuclear nanostructures such as lamin A/C and chromatin. It is also found that nuclear modulus is strongly regulated by cytoskeletal behavior through a robust mechanism conserved in different culturing conditions. Given the active role of cytoskeletal modulation in nearly all cell functions, this work will enable to reveal highly relevant mechanisms of nuclear mechanical regulations in physiological and pathological conditions.

Assessing the biomechanical properties of the crystalline lens can provide crucial information for diagnosing disease and guiding precision therapeutic interventions. Existing noninvasive methods have been limited to global measurements. Here, we demonstrate the quantitative assessment of the elasticity of crystalline lens with a multimodal optical elastography technique, which combines dynamic wave-based optical coherence elastography (OCE) and Brillouin microscopy to overcome the drawbacks of individual modalities. OCE can provide direct measurements of tissue elasticity rapidly and quantitatively, but it is a challenge to image transparent samples such as the lens because this technique relies on backscattered light. On the other hand, Brillouin microscopy can map the longitudinal modulus with micro-scale resolution in transparent samples. However, the relationship between Brillouin-deduced modulus and Young’s modulus is not straightforward and sample dependent. By combining these two techniques, we can calibrate Brillouin measurements with OCE, based on the same sample, allowing us to completely map the Young’s modulus of the crystalline lens. The combined system was first validated with tissue-mimicking gelatin phantoms of varying elasticities (N = 9). The OCE data was used to calibrate the Brillouin shift measurements and subsequently map the Young’s modulus of the phantoms. After validation, OCE and Brillouin measurements were performed on ex-vivo porcine lenses (N = 6), and the Young’s modulus of the lenses was spatially mapped. The results show a strong correlation between Young’s moduli measured by OCE and longitudinal moduli measured by Brillouin microscopy. The correlation coefficient R was 0.98 for the phantoms and 0.94 for the lenses, respectively. The mean Young’s modulus of the anterior and posterior lens was 1.98 ± 0.74 kPa and 2.93 ± 1.13 kPa, respectively, and the Young’s modulus of the lens nucleus was 11.90 ± 2.94 kPa. The results presented in this manuscript open a new way for truly quantitative biomechanical mapping of optically transparent (or low scattering) tissues in 3D.

Terahertz (THz) spectroscopy with high sensitivity is essential for biological application considering the strong absorption and scattering effects therein. As the most commonly used THz detector, the photoconductive antenna’s (PCA) response greatly relies on the properties of the substrate’s material. THz detection properties of the PCAs fabricated on low-temperature-grown GaAs (LT-GaAs) and ErAs:GaAs superlattices were compared at the sub-THz band. The detection efficiency of the PCAs with regard to incident laser power was characterized. In addition, using the PCAs as detectors, the signal-to-noise ratio (SNR) and dynamic range (DR) of a terahertz time-domain spectroscopy were quantified. The result indicates that the PCA detector with LT-GaAs has higher efficiency than the one with ErAs:GaAs. Consequently, the corresponding THz spectrometer has better SNR and DR. This result is contrary to the previous report, in which enhanced detection efficiency was observed with ErAs:GaAs-based PCA, which is probably due to the different structures of ErAs:GaAs superlattices used in the experiment.

A methodology of rotating the applied static magnetic field on Ni0.8Zn0.2Fe2O4 (NZFO)/PZT-8 magnetoelectric laminate, was introduced to realize 180° phase reversal with constant amplitude, which is invariably required for phase-based communication system, engineering technology and microelectronic devices. Through further decoding the phase information existed in magnetoelectric coefficient, we found that the undistorted 180° phase reversal can be achieved once the applied field was reversed. Moreover, piezomagnetic response can essentially track the magnetoelectric response under optimum bias with the variations of rotation angle, and then the origins can be well explained. Experimental results show that the maximum resonance ME voltage coefficient of +51.72 V/cm Oe and −51.93 V/cm Oe were obtained in angle of θ = 0° and 180°, respectively. These results provide great possibilities for practical applications in ME phase shifters and inverters.

Quantifying the temporal and spatial patterns of temperature sensitivity (Q10) of soil respiration (Rs) as well as its controlling factors is critical to reveal the response the soil ecological processes to global warming and improve carbon budget estimations at a regional scale. The seasonal and annual variations in the temperature response of Rs were assessed during the two growing seasons in 2011 and 2012 in four different vegetation sites in a meadow steppe of the Songnen Plain, China. The Q10 values across all sites exhibited significant seasonal variations with a minimum value (1.81–2.34) occurring during summer and a peak value (3.82–4.54) occurring in either spring or autumn. The mean seasonal Q10 values showed no significant differences among the four different vegetation types. On the annual scale, however, the Chloris virgata site had significantly higher annual Q10 values (3.67–4.22) than the other three community sites in 2011 and 2012 and over the two years (2.01–3.67), indicating that the response of the Rs to climate warming may vary with vegetation type. The soil temperature and moisture had interactive effects on the variations of Q10 values. Soil temperature was the dominant factor influencing Q10 values, while soil moisture was an additional contributor to the variations of Q10. Due to the significant temporal and spatial variations in soil respiration response to temperature, acclimation of Rs to temperature variation should be taken into account in forecasting future terrestrial carbon cycle and its feedback to global warming.

The terahertz (THz) radiation properties of a photoconductive antenna (PCA) fabricated on a GaAs-on-sapphire (GoS) substrate are reported at sub-THz band. The GaAs layer with a thickness of approximately 1 µm was directly deposited on a sapphire wafer by means of molecular beam epitaxy. A butterfly-shaped antenna structure was then fabricated on the GoS substrate by photolithography, and the device was tested as the emitter of an in-house built THz time-domain spectrometer. The performance of this antenna was compared with a commercial one, which had an identical antenna structure but was fabricated on low-temperature-grown GaAs (LT-GaAs). The results showed that the GoS-based PCA radiated an enhanced THz field, which could be as much as 1.9 times that of the LT-GaAs-based PCA, indicating that GoS could be a promising photoconductive material. In addition, the optical transparency of the sapphire substrate allows the device to be illuminated from the backside, which is crucial for THz near-field imaging applications where the sample is usually in close proximity to the front surface of the PCA device.The terahertz (THz) radiation properties of a photoconductive antenna (PCA) fabricated on a GaAs-on-sapphire (GoS) substrate are reported at sub-THz band. The GaAs layer with a thickness of approximately 1 µm was directly deposited on a sapphire wafer by means of molecular beam epitaxy. A butterfly-shaped antenna structure was then fabricated on the GoS substrate by photolithography, and the device was tested as the emitter of an in-house built THz time-domain spectrometer. The performance of this antenna was compared with a commercial one, which had an identical antenna structure but was fabricated on low-temperature-grown GaAs (LT-GaAs). The results showed that the GoS-based PCA radiated an enhanced THz field, which could be as much as 1.9 times that of the LT-GaAs-based PCA, indicating that GoS could be a promising photoconductive material. In addition, the optical transparency of the sapphire substrate allows the device to be illuminated from the backside, which is crucial for THz near-field imaging a...

Saturation cavity ring-down spectroscopy (SCRDS) is a powerful Doppler-free spectroscopy means for measuring absolute frequencies of transitions at the ultra-low uncertainties. We report in this paper a simple way to implement it by temperature scanning the cavity length, which circumvents the need for a complex optical cavity-length stabilization system based upon a piezoelectric actuator (PZT). To demonstrate this approach, the absolute frequencies of the two transitions, R6F1 of the 2v3 and Q9A1 of the 2v2 + v3 bands, of 12CH4, are determined to be 182 185 269.362(20) MHz and 182 187 617.543(39) MHz. The accuracy of measurements is improved by about 3-4 orders of magnitude when compared to those obtained with conventional spectroscopic methods.

Ferrite-ferroelectric core-shell nanoparticles were prepared by deoxyribonucleic acid (DNA) assisted self-assembly and the strained mediated magneto-electric (ME) interactions between the ferroic phases were studied. The nanoparticle type and size were varied and the DNA linker sequence was also varied. Two kinds of particles, one with 600 nm barium titanate (BTO) core and 200 nm nickel ferrite (NFO) shell and another with 200 nm BTO core and 50 nm nickel cobalt ferrite (NCFO) shell were prepared. The particles were linked by three different oligomeric DNA containing 19, 18 or 30 base pairs. The core-shell structure was evident from electron microscopy and scanning microwave microscopy images. Films and disks of the core-shell particles were assembled in a magnetic field and used for measurements of low frequency ME voltage coefficient (MEVC) and magnet-dielectric effect. The MEVC data on films indicate that particles assembled with DNA with 30 base pairs exhibit the strongest ME coupling suggesting a more fully integrated heterogenous nanocomposite and the weakest interaction for DNA with 18 base pairs. These results indicate that the longer linker region in DNA is the key factor for forming better composites. This result may be due to the irregular shape of the nanoparticles. Longer DNA strands would be able to bridge better generating more linkages. Shorter strands would not able to bridge the irregularly shaped particles as well and therefore result in linkages and less heterogeneity in the composites.

The 2v3 R6 manifold of methane is important for remote sensing. The positions of 96 lines in this manifold were determined by both Lamb-dip spectroscopy and linear absorption spectroscopy using a cavity ring-down spectrometer.

Ferromagnetic–ferroelectric nanocomposites are of interest for realizing strong strain-mediated coupling between electric and magnetic subsystems due to a high surface area-to-volume ratio. This report is on the synthesis of nickel ferrite (NFO)–barium titanate (BTO) core–shell nanofibers, magnetic field assisted assembly into superstructures, and studies on magneto-electric (ME) interactions. Electrospinning techniques were used to prepare coaxial fibers of 0.5–1.5 micron in diameter. The core–shell structure of annealed fibers was confirmed by electron microscopy and scanning probe microscopy. The fibers were assembled into discs and films in a uniform magnetic field or in a field gradient. Studies on ME coupling in the assembled films and discs were done by magnetic field (H)-induced polarization, magneto–dielectric effects at low frequencies and at 16–24 GHz, and low-frequency ME voltage coefficients (MEVC). We measured ~2–7% change in remnant polarization and in the permittivity for H = 7 kOe, and a MEVC of 0.4 mV/cm Oe at 30 Hz. A model has been developed for low-frequency ME effects in an assembly of fibers and takes into account dipole–dipole interactions between the fibers and fiber discontinuity. Theoretical estimates for the low-frequency MEVC have been compared with the data. These results indicate strong ME coupling in superstructures of the core–shell fibers.

An autonomous current-sensing system consisting of a SmFe 2 /PZT/SmFe 2 self-biased magnetoelectric (ME) composite and a Fe 73.5 Cu 1 Nb 3 Si 13 . 5 B 9 nanocrystalline flux concentrator for weak current detection at the power-line frequency is presented and characterized. Giant magnetostrictive material of SmFe2 plate with large anisotropic constant provides a huge internal anisotropic field to bias the ME sensors in a closed magnetic loop. Consequently, the additional magnetomotive force induced by the internal field as well as the corresponding increased effective permeability contributes to the sensitivity improvement. Experimental results demonstrate that the presented sensor has a higher sensitivity of 152 mV/A at 50Hz with a slight nonlinearity of ∼0.01%FS and matches well with the predicted value. This presented current-sensing device exhibits approximately 2.3 times higher sensitivity than that of conventional ME composite with PZT and Terfenol-D plates serving as the key sensitive component. These results provide a significant advancement toward promising application of the tri-layer self-biased ME laminate for power-line electric cords monitoring.

Nucleus is the largest and usually stiffest organelle in a eukaryotic cell. Thus its mechanical properties is tightly related to various cell functions and activities. In this work, we developed a label-free flow cytometry platform to characterize the nuclear mechanics with the help of Brillouin microscopy, which is an all-optical technique so that can measure the stiffness of the nucleus in a non-contact, non-invasive and label-free manner. We demonstrate that Brillouin flow cytometry is able to detect physiologically-relevant changes in nuclear stiffness with enough sensitivity.

This report is on the observation and theory for strong mechanical strain mediated magneto-electric (ME) coupling in composites of lead zirconate titanate (PZT) and self-biased Y- or W-type hexagonal ferrites. Polycrystalline Y-type (Ni1−xZnx)2 Y, and W-type (Co1−xZnx)2 W, hexagonal ferrites for x = 0–0.4 prepared by ceramic processing techniques showed a large remanent magnetization due to uniaxial or in-plane magneto-crystalline anisotropy. The strength of ME coupling in symmetric trilayer composites of the ferrites and PZT was measured by the ME voltage coefficient (MEVC) at low-frequencies and at longitudinal electromechanical resonance. The bias magnetic field H-dependence of MEVC at low-frequencies in the composites with (Ni, Zn) Y showed hysteresis with its value under self-bias 90% or more of the value for the optimum bias field. In the case of composites with W-type ferrites, the MEVC under zero-external bias was 60%–80% of its value for the optimum bias field. Both types of composites when subjected to an ac magnetic field at the EMR frequency showed an order of magnitude enhancement in the MEVC compared to low-frequencies and the peak value at EMR for zero-bias was 90% of its value under the optimum bias. A model has been developed for the large ME response under the self-bias provided by the remanent magnetization and estimated values of MEVC are in good agreement with the data. The hexaferrite-ferroelectric composites showing ME response without the need for an external magnetic bias are of importance for use as sensors and sensor arrays of magnetic fields.

Magnetoelectric (ME) gyrators consisting of system of Sm-doped NiZn ferrites (Ni1-xZnxSm0.02Fe1.98O4, 0.2≤x≤0.5) and piezoelectric ceramics [Pb(Zr, Ti)O3] with coil wound around have been developed. Distinct hysteresis behaviors were observed in off-resonance ME couplings and power conversion efficiency (PE) characterizations, resulting in a non-zero ME response and anticipating a higher remanent PE at zero bias. Consequently, light samarium doping facilitates the enhancement of PE, which reaches its maximum of 81.5% under optimum bias and self-biasing value of 58.5% under zero bias in the composite of Ni0.8Zn0.2Sm0.02Fe1.98O4/PZT trilayer respectively, exhibiting approximately 2.2 times higher than the counterpart without any samarium doping. These findings provide great possibilities of ME gyrators for miniaturized devices deployed in power electronics, converters and wireless energy harvesters without a sacrifice in magneto-mechanical efficiency.

We propose a new simple approximate solution to the two-state rate equation model for analyzing decay signals of saturation cavity ring-down spectrometry in the adiabatic and low-saturation regime. It helps obtain baseline-immune Doppler-free spectra for hyperfine transitions and linear absorption coefficients of a gas in the saturation regime. To demonstrate it, a baseline-immune Lamb dip spectrum of the R1A2 transitions in the 2v2 + v3 band of methane was recorded. The line position was determined to be 6 076.108 457 7(11) cm−1, the relative uncertainty being 1.8 × 10−10.

A tunable magnetoelectric inductor composed of a symmetrical trilayer of Ga-doped NiZn ferrite and PZT in a solenoid has been developed. Under the influence of external electric/magnetic fields, the permeability variation arising from magnetostriction and piezoelectric strain in the composite results in a bidirectional tuning of the inductance L with a maximum tunability of 571% at a lower magnetic field. The largest variation in L occurs for frequencies centered around longitudinal acoustic resonance. The dual and large tunability of L is of importance for applications in compact and power-efficient integrated circuits.

A model is developed for magnetoelectric (ME) interactions in coaxial nanofibers of hexagonal ferrites and ferroelectrics. Multiferroic nanocomposites with hexagonal ferrites are of interest for achieving strong ME coupling under zero external magnetic bias due to their high uniaxial or planar anisotropy fields. In this work we considered the ME coupling in core–shell fibers of lead zirconate titanate (PZT) and ferrimagnetic W- and Y-type hexagonal ferrites with high magnetostriction and piezomagnetic coupling. Modeling of the direct-ME effects, i.e. sample response to an applied magnetic field, is done in terms of the ME voltage coefficients (MEVCs) at low frequencies and at electromechanical resonance (EMR). The converse-ME effect, response of the fibers to an applied DC electric field, is considered at ferromagnetic resonance (FMR). Expressions have been obtained for MEVCs at low frequency and EMR, and for the converse-ME coefficient at FMR. The theory predicts strongest direct-ME coupling in fibers of Ni2Y-PZT and the weakest coupling in Zn2Y-PZT. The MEVC at EMR is one to two orders of magnitude higher than at low frequency and the peak MEVC remains the same for fibers of ferrite core-PZT shell as for PZT core-ferrite shell. The converse-ME effect is expected to be the strongest for fibers of Co2W-PZT and weakest in Ni2Y-PZT. The model has been extended to include an assembled array of core–shell fibers and weakening of the ME coupling is predicted in such arrays due to magnetic and electric dipole–dipole interactions. The theory presented here is of importance for self-biased sensors of low frequency and RF magnetic fields.

Hydrogen sulfide (H2S), as a typical atmospheric pollutant, is neurotoxic and flammable even at a very low concentration. In this study, we design stable H2S sensors based on ZnO-carbon nanofibers. Nanofibers with 30.34 wt% carbon are prepared by a facial electrospinning route followed by an annealing treatment. The resulting H2S sensors show excellent selectivity and response compared to the pure ZnO nanofiber H2S sensors, particularly the response in the range of 102-50 ppm of H2S. Besides, they exhibited a nearly constant response of approximately 40-20 ppm of H2S over 60 days. The superior performance of these H2S sensors can be attributed to the protection of carbon, which ensures the high stability of ZnO, and oxygen vacancies that improve the response and selectivity of H2S. The good performance of ZnO-carbon H2S sensors suggests that composites with oxygen vacancies prepared by a facial electrospinning route may provide a new research strategy in the field of gas sensors, photocatalysts, and semiconductor devices.

This report is on a new class of magnetostatically tunable magneto-impedance and magneto-capacitance devices based on a composite of ferromagnetic Metglas and ferroelectric lead zirconate titanate (PZT). Layered magneto-electric (ME) composites with annealed Metglas and PZT were studied in a longitudinal in-plane magnetic field-transverse electric field (L-T) mode. It was found that the degree of tunability was dependent on the annealing temperature of Metglas. An impedance tunability (ΔZ/Z0) of ≥400% was obtained at the electromechanical resonance (EMR) frequency (fr) for a sample with Metglas layers annealed at Ta = 500oC. This tunability is a factor of two higher than for composites with Metglas annealed at 350oC. The tunability of the capacitance, (ΔC/C0), was found to be 290% and -135k% at resonance and antiresonance, respectively, for Ta = 500oC. These results provide clear evidence for improvement in static magnetic field tunability of impedance and capacitance of ME composites with the use of annealed Metglas and are of importance for their potential use in tunable electronic applications.