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Measuring the solubility of a crystalline active pharmaceutical ingredient (API) in a polymer-rich system is challenging due to the high viscosity of the polymer which kinetically impedes reaching the solubility equilibrium. In this study, a rheological approach of determining the solubilizing temperature of a crystalline API in a polymeric carrier has been developed. To validate the method, a model physical mixture of crystalline posaconazole and copovidone with a relatively low API load (25 wt%) was utilized. First, a comparison between conventional differential scanning calorimetry (DSC) and a rheological temperature ramp was conducted to illustrate that the rheological method could capture the melting point depression behavior similarly to the more well-known DSC technique. Second, to further understand the dissolution process of the crystalline posaconazole into the copovidone carrier and precisely measure the solubilizing temperature, a series of isothermal rheological time sweeps were carried out at various temperatures selected based on the rheological temperature sweep. Because the dissolved API molecule imparted a plasticizing effect to the polymeric carrier, the complex viscosity of the API-polymer system decreased gradually over time and correlated well to an exponential decay function. Moreover, dependent on the applied temperature, the API-polymer system eventually accomplished distinct equilibrium states (complex viscosities) within different time frames. The obtained time constants at different temperatures were fitted to the Arrhenius equation, allowing the determination of the activation energy of the mixing process. The results indicated that once the processing temperature exceeded a critical point below the melting point of the crystalline API, the API-polymer solubilization process switched from a surface dominated dispersive mechanism to a molecular-level solubilization mode, manifested by the significantly increased activation energy. To the best of our knowledge, the currently developed rheological approach was the first successful measurement of the solubilizing temperature of a crystalline drug in a polymer-rich system.

Skyrmion imaging and electrical detection via topological Hall (TH) effect are two primary techniques for probing magnetic skyrmions, which hold promise for next-generation magnetic storage. However, these two kinds of complementary techniques have rarely been employed to investigate the same samples. We report the observation of nanoscale skyrmions in SrIrO3/SrRuO3 (SIO/SRO) bilayers in a wide temperature range from 10 to 100 K. The SIO/SRO bilayers exhibit a remarkable TH effect, which is up to 200% larger than the anomalous Hall (AH) effect at 5 K, and zero-field TH effect at 90 K. Using variable-temperature, high-field magnetic force microscopy (MFM), we imaged skyrmions as small as 10 nm, which emerge in the same field ranges as the TH effect. These results reveal a rich space for skyrmion exploration and tunability in oxide heterostructures.

The dynamic responses of large-span space structures are significantly associated with some higher structural frequency modes. A proper finite element model with accurate modal damping ratios is a key factor in obtaining precise structural seismic responses in numerical analyses. The complex damping model is often used in frequency domain structural analyses because of its characteristics of constant modal damping ratio with frequency and frequency-independent energy dissipation. Based on the five-parameter integer-order derivative method, a user subroutine of ABAQUS is developed to estimate the complex damping model in time-domain dynamic analyses. A shaking table test of a scaled and simplified single-layer reticulated dome is first conducted to validate the user subroutine. Detailed test data, including the identified natural frequencies and modal damping ratios, free vibration curves, and representative maximum responses, are summarized and compared with the corresponding finite element results using the complex damping model and a Rayleigh damping model. The comparisons indicate that the results of the complex damping model can yield a better estimation of the test data. Finally, the effect of the complex damping on the seismic responses of a single-layer reticulated dome is systematically studied by comparing the structural frequency properties and dynamic characteristic responses with those of Rayleigh damping. The results show that the complex damping model provides smaller structural modal damping ratio variation, lower ultimate seismic loading, and severer structural plastic developments.

The parameter server system (Parameter Server, PS) is the most widely used distributed machine learning system. Its core module is the communication module, which mainly includes three parts: communication content, communication frequency, and communication pace. The communication scheme of the existing PS system will have problems such as waste of computing power resources and a large proportion of communication overhead. This paper hopes to design and implement a distributed set that saves computing power and has a smaller communication overhead based on the communication module of the original PS system. This article mainly innovates in following aspects: First, through the analysis and experiment of Bulk Synchronous Parallel (BSP) communication pace, based on the superiority of BSP algorithm level, it overcomes the waste of computing power of BSP at the system level, and designs and implements a new set of Communication pace, the new communication pace under the same training task can save more computing power and achieve higher model accuracy. Secondly, this article combines the quantization compression technology with the parameter server system, and uses the quantization technology to compress and decompress the communication content in the parameter server system, so that the volume of the communication content during the operation of the parameter server system is significantly reduced, thereby reducing the communication overhead and improving Speedup ratio of the system. Finally, based on the analysis and experiment of the change trend of the model accuracy rate, this paper designs and implements a dynamic communication frequency adjustment scheme based on the change trend of the model accuracy rate, which reduces the overall communication frequency during the operation of the parameter server system and reduces the parameter server. Experiments show that the system designed in this paper is superior to the existing mainstream solutions in terms of communication pace, communication content, and communication frequency.

Author(s): Cogulu, E; Statuto, NN; Cheng, Y; Yang, F; Chopdekar, RV; Ohldag, H; Kent, AD | Abstract: We report the direct observation of switching of the Neel vector of antiferromagnetic (AFM) domains in response to electrical pulses in micron-scale Pt/α-Fe2O3 Hall bars using photoemission electron microscopy. Current pulses lead to reversible and repeatable switching with the current direction determining the final state, consistent with Hall effect experiments that probe only the spatially averaged response. Current pulses also produce irreversible changes in domain structure, in and even outside the current path. In both cases only a fraction of the domains switch in response to pulses. Furthermore, the analysis of images taken with different x-ray polarizations shows that the AFM Neel order has an out-of-plane component in equilibrium that is important to consider in analyzing the switching data. These results show that - in addition to effects associated with spin-orbit torques from the Pt layer, which can produce reversible switching - changes in AFM order can be induced by purely thermal effects.

We report a resonant elastic x-ray scattering study of a thin-film sample of ${\mathrm{Sr}}_{2}{\mathrm{CrReO}}_{6}$, which has one of the highest ferrimagnetic transition temperatures among ordered double perovskites. We found resonantly enhanced magnetic Bragg peaks at $\mathbf{Q}=$ (odd, odd, odd) at both the rhenium ${L}_{2}$ and ${L}_{3}$ edges, which coincide with the structural Bragg peaks of ${\mathrm{Sr}}_{2}{\mathrm{CrReO}}_{6}$. By analyzing the widths of these Bragg peaks, we extracted very different structural and magnetic correlation lengths. The former is about 15 nm, while the latter is constrained by the instrumental resolution to be at least 90 nm. We argue that a finite structural correlation length is consistent with the existence of antiphase nanodomains in our sample. On the other hand, a much larger magnetic correlation length indicates that the magnetic correlation extends far beyond the boundaries of individual domains and is consistent with strong antiferromagnetic coupling between different antiphase domains. Last, from the azimuthal dependence of the magnetic intensity, we show that the magnetic moments lie perpendicular to the $c$ axis, which explains the earlier bulk magnetization data.

The characteristics of passive responses and fixed band gaps of phononic crystals (PnCs) limit their possible applications. For overcoming this shortcoming, a class of tunable PnCs comprised multiple scatterers and soft periodic porous elastomeric matrices are designed to manipulate the band structures and directionality of wave propagation through the applied deformation. During deformation, some tunable factors such as the coupling effect of scatterer and hole in the matrix, geometric and material nonlinearities, and the rearrangement of scatterer are activated by deformation to tune the dynamic responses of PnCs. The roles of these tunable factors in the manipulation of dynamic responses of PnCs are investigated in detail. The numerical results indicate that the tunability of the dynamic characteristic of PnCs is the result of the comprehensive function of these tunable factors mentioned earlier. The strong coupling effect between the hole in the matrix and the scatterer contributes to the formation of band gaps. The geometric nonlinearity of matrix and rearrangement of scatterer induced by deformation can simultaneously tune the band gaps and the directionality of wave propagation. However, the matrix’s material nonlinearity only adjusts the band gaps of PnCs and does not affect the directionality of wave propagation in them. The research extends our understanding of the formation mechanism of band gaps of PnCs and provides an excellent opportunity for the design of the optimized tunable PnCs and acoustic metamaterials (AMMs).

Layered structures are widely used in optics to control wave reflection and propagation at interfaces but their thickness relative to the wavelength hinders their application in the radio-frequency regime. Here, we design and experimentally demonstrate cascaded metasurfaces with deeply subwavelength thickness that provide both antireflection and wavefront manipulation. We describe the systematic synthesis of the metasurface layers from a prescribed scattering response and demonstrate designs capable of providing near-perfect microwave transmission through glass as well as antireflection focusing of wireless signals from air into water.

Ferrimagnetic insulators capped with a heavy metal are becoming an increasingly interesting materials system in spintronics due to their unique ability for electrical manipulation and detection of magnetic states and spin textures via spin-orbit torques. The ability to engineer magnetic anisotropy is a powerful tool for tuning the recently discovered phenomena in these bilayers such as electrical switching or the stabilization of topological magnetic textures. We observe large shifts in the magnetic anisotropy in ${\mathrm{Tm}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ and ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ thin films due to heavy-metal capping layers, which strongly depends on the orientation of the substrate and therefore the orientation of the epitaxial films. This work suggests large Rashba spin-orbit coupling at the metal/ferrimagnetic-insulator interface, which can be engineered in spintronic devices that utilize spin-orbit torques for electrical control of the magnetization in magnetic insulators.

Nonlocal spin transport using lateral structures is attractive for spintronic devices. Typically, a spin current is generated by a ferromagnetic (FM) or a heavy metal (HM) electrode in a nonlocal structure, which can be detected by another FM or HM electrode. Here, we report a new nonlocal spin injection scheme using uniform-mode ferromagnetic resonance (FMR) spin pumping in Pt/Y

The fixed band gap characteristic of passive phononic crystals (PCs) is possible to limit their applications in engineering. To overcome this shortcoming, inspired by the tunable mechanism of the spider silks, a new class of tunable PCs comprising periodic scatterers and periodic elastomeric matrix are proposed to effectively tune the band gaps and directionality of propagating waves. The orientation and arrangement of hard scatterers are controlled by the deformation of the periodic elastomeric matrix to enhance the tunability of their dynamic responses. According to this idea, PCs with differently shaped and arranged cylindroid scatterers are designed. Through introducing the multiple scatterers into the periodic elastomeric matrix, the scattering coupling effect between them is enhanced. The simulation results indicate that the orientation and arrangement of the scatterers could be altered continuously during deformation. During deformation, the number, position, and width of band gaps can be effectively tuned due to the geometric nonlinearity of the matrix and the rearrangement of multiple scatterers. The transmissibility of finite-sized structures without damping decreases significantly in the frequency ranges of band gaps. However, introducing the damping into the matrix material significantly enhances the ability to suppress elastic wave propagation but makes it difficult to identify the band gaps from the transmittance spectrum. The directionality of wave propagation can be also effectively tuned. In the low-frequency range, such as the first two phase constant surfaces, the phase and group velocity profiles and the anisotropy indexes are calculated and the results indicate that the deformation makes the wave propagation more isotropic. The schemes presented in this paper provide an effective approach to tune the band gaps of the solid/solid PCs and open avenues for the design of tunable PCs.

Local strain-dependent spin-polarized electronic structure of a two-dimensional (2D) magnetic layer is an exciting property for practical applications. For example, it holds the promise for advanced ultrathin spintronic nanodevices with customized electronic and magnetic properties by local strain engineering. Here, we demonstrate that the spin-polarized electronic structure of a 2D manganese gallium nitride (MnGaN-2D) magnetic monolayer is sensitive to intrinsic local lattice strain, as proven by first-principles calculations and indicated by scanning tunneling spectroscopy measurements. Atomic resolution images reveal a highly non-Gaussian lattice spacing/strain distribution, while the spectroscopy reveals variations in the electronic density of states. Simulations of the MnGaN-2D monolayer based on first-principles calculations, including both isotropic and anisotropic strains, confirm a highly strain-dependent manganese partial density of states. Spin-orbit coupling is included which indicates either out-of-plane perpendicular magnetic anisotropy (PMA) or in-plane magnetic anisotropy, dependent on the type of strain whether compressive or tensile, suggesting that MnGaN-2D is magnetoelastic. The MnGaN-2D PMA is further supported by superconducting quantum interference device magnetometry measurements which reveal a high spin polarization of $\ensuremath{\sim}79$% at room temperature.

Topological magnetic textures such as skyrmions are being extensively studied for their potential application in spintronic devices. Recently, low-damping ferrimagnetic insulators (FMI) such as Tm3...

This study investigated the effect of binder level on the physicochemical changes and tabletability of acetaminophen (APAP)-hydroxypropyl cellulose (HPC) granulated using twin-screw melt granulation. Even at 5% HPC level, the tablet tensile strength achieved up to 3.5 MPa. A minimum of 10% HPC was required for the process robustness. However, 20% HPC led to tabletability loss, attributable to the high mechanical strength of APAP granules. The over-granulated APAP granules had thick connected HPC scaffold and low porosity. Consequently, these granules were so strong that they underwent a lower degree of fracture under compression and higher elastic recovery during decompression. HPC was enriched on the surface of APAP extrudates at all HPC levels. Amorphous APAP was also observed on the extrudate surface at 20% HPC level, and it recrystallized within 24 h storage. To achieve a robust process and optimal improvement in APAP tabletability, the preferred HPC level was 10 to 15%.

An investigation of underlying mechanisms of API-polymer interaction patterns has the potential to provide valuable insights for selecting appropriate formulations with superior physical stability and processability.In this study, copovidone was used as a polymeric carrier for several model compounds including clotrimazole, nifedipine, and posaconazole. The varied chemical structures conferred the ability for the model compounds to form distinct interactions with copovidone. Rheology and nuclear magnetic resonance (NMR) were combined to investigate the molecular pattern and relative strength of active pharmaceutical ingredient (API)-polymer interactions. In addition, the impact of the interactions on formulation processability via hot melt extrusion (HME) and physical stability were evaluated.The rheological response of an API-polymer system was found to be highly sensitive to API-polymer interaction, depending both on API chemistry and API-polymer miscibility. In the systems studied, dispersed API induced a stronger plasticizer effect on the polymer matrix compared to crystalline/aggregated API. Correspondingly, the processing torque via HME showed a proportional relationship with the maximum complex viscosity of the API-polymer system. In order to quantitatively evaluate the relative strength of the API-polymer interaction, homogeneously dispersed API-polymer amorphous samples were prepared by HME at an elevated temperature. DSC, XRD, and rheology were employed to confirm the amorphous integrity and homogeneity of the resultant extrudates. Subsequently, the homogeneously dispersed API-polymer amorphous dispersions were interrogated by rheology and NMR to provide a qualitative and quantitative assessment of the nature of the API-polymer interaction, both macroscopically and microscopically. Rheological master curves of frequency sweeps of the extrudates exhibited a strong dependence on the API chemistry and revealed a rank ordering of the relative strength of API-copovidone interactions, in the order of posaconazolenifedipineclotrimazole. NMR data provided the means to precisely map the API-polymer interaction pattern and identify the specific sites of interaction from a molecular perspective. Finally, the impact of API-polymer interactions on the physical stability of the resultant extrudates was studied.Qualitative and quantitative evaluation of the relative strength of the API-polymer interaction was successfully accomplished by utilizing combined rheology and NMR. Graphical Abstract.

Near-infrared (NIR) activatable upconversion nanoparticles (UCNPs) enable wireless-based phototherapies by converting deep-tissue-penetrating NIR to visible light. UCNPs are therefore ideal as wireless transducers for photodynamic therapy (PDT) of deep-sited tumors. However, the retention of unsequestered UCNPs in tissue with minimal options for removal limits their clinical translation. To address this shortcoming, biocompatible UCNPs implants are developed to deliver upconversion photonic properties in a flexible, optical guide design. To enhance its translatability, the UCNPs implant is constructed with an FDA-approved poly(ethylene glycol) diacrylate (PEGDA) core clad with fluorinated ethylene propylene (FEP). The emission spectrum of the UCNPs implant can be tuned to overlap with the absorption spectra of the clinically relevant photosensitizer, 5-aminolevulinic acid (5-ALA). The UCNPs implant can wirelessly transmit upconverted visible light till 8 cm in length and in a bendable manner even when implanted underneath the skin or scalp. With this system, it is demonstrated that NIR-based chronic PDT is achievable in an untethered and noninvasive manner in a mouse xenograft glioblastoma multiforme (GBM) model. It is postulated that such encapsulated UCNPs implants represent a translational shift for wireless deep-tissue phototherapy by enabling sequestration of UCNPs without compromising wireless deep-tissue light delivery. Ministry of Education (MOE) Nanyang Technological University This work was supported by National University of Singapore’s start up grants, R-183-000-413-733 and R-185-000-363-733; Singapore’s Ministry of Education grants (MOE 2016-T3-1-004, R-397-000-274-112, R-397-000-270-114); and a Lee Kong Chian School of Medicine, Nanyang Technological University start-up grant.

In this work, we present our novel approach to explore high-order harmonic generation from solids by introducing a two-color scheme that combines an 80 fs, 3.6 µm mid-infrared driving field with a 2 ps, 600 µm single-cycle terahertz dressing field.

In this paper, we present HealCam, an energy-efficient and privacy-preserving human vital signs (e.g., respiration cycles) monitoring system on camera-enabled smart devices. HealCam incorporates the related theories of compressive sensing in its system to reduce the sampling rate while preserving data privacy. HealCam saves significant cost on video processing via low-rate and non-uniform random sampling. It also provides a privacy-preserved data collection and enquiry service via lightweight compressive encryption and decryption scheme. According to our evaluations on real datasets, HealCam achieves high accuracy on respiration cycles reconstruction with extremely low average frame rate, i.e., 1 FPS, via non-uniform random sampling compared with traditional uniform sampling strategy. Then we implement HealCam on smartphones to evaluate its resource consumption. The results show that, HealCam is 23.6 times more energy efficient and 26.7 times faster than the original approach on video processing. Its data encryption component is 172 times faster while consumes only 1.01% energy compared with the corresponding state-of-the-art.

This paper presents a new method to improve the insulation defect classification rate of DC cross linked polyethylene (XLPE) cables. A partial discharge (PD) test platform is built in the laboratory and four DC cable defect models are designed. The PD signal is collected by a high frequency current transducer (HFCT) and the q-At-n image is constructed. The contourlet transform is performed on the PD image, and the Tsallis entropy feature of each subband coefficient is calculated. The error-correcting output codes (ECOC) classifier is optimized by the adaptive cuckoo search (ACS) algorithm optimization sparse random (SR) coding matrix to realize the defect classification. The experimental data show that the ACS-SR-ECOC classifier in this paper has shown promising performance in the classification of each defect and the Gaussian noise model. Compared with to four kinds of traditional ECOC classifiers, the proposed method has higher overall classification accuracy, which provides a new approach for the defect type identification of PD image in the DC cable.

A new method to extract the features of direct current (DC) cross linked polyethylene (XLPE) cable partial discharge (PD) image based on non-subsampled contourlet transform (NSCT) is proposed in this paper. Four types of PD images are obtained from the artificially designed cable insulation defects. The features include Shannon entropy, Renyi entropy, Euclidean distance, and Mahalanobis distance of the optimized subband coefficients by NSCT. The optimized subband coefficients are selected by the immune algorithm optimized affinity propagation clustering method. The back propagating neural network, k-nearest neighbor, support vector machine and decision tree algorithms are used to classify the extracted features. The experimental results show that the proposed method can be applied to the feature extraction of PD signals in DC XLPE cables. Compared with the wavelet method, the recognition rate of the method is improved by more than 16.80% under the same classifier. It is found that the type of defect within insulation can be classified efficiently with the features extracted by the proposed method with a reasonable degree of accuracy.

Multilayer structures have found extensive applications in personal protection engineering, which are considered effective materials in mitigating shock loads. In this paper, the effect of layer thickness and layout on the shock mitigation performance of multilayer structures is evaluated experimentally, and the mitigation mechanism is analyzed. The tested structures are designed into three groups, composing of four protection materials, including ultra-high molecular weight polyethylene composite (PE), wooden laminated composite (Wood), polyurea (PU), and expanded polyethylene foam (Foam). In the experiment, a pressure test platform is developed to measure the transmitted shock pressure pulse after passing through the structure, and the tested structure supported by the platform is subjected to the shock loads generated by a shock tube facility. Experimental results indicate that the transmitted pressure amplitude can be considerably reduced by increasing the thickness of the Foam layer. Besides, with the same thickness, when the Foam layers are staggered and arranged within the structure, the transmitted pressure amplitude is much higher than that of when they are entirely arranged as the back layer within the structure. Further, a new energy transmission model is proposed to reveal the shock mitigation mechanism, which considers that the output energy transmitted into the target is generated jointly by the input energy from the shock loads and the energy transmission efficiency of the structure. The specific energy values are quantitively calculated through numerical simulation. Results indicate that for different layer layouts of designed structures, the energy transmission efficiency changes little, but the input energy varies a lot. Arranging the Foam layers as the back layer within the structure can reduce their compressed deformation under shock loads, which contributes to much less input energy and better mitigation performance.

Shape-morphing magnetic soft materials, composed of magnetic particles in a soft polymer matrix, can transform shape reversibly, remotely, and rapidly, finding diverse applications in actuators, soft robotics, and biomedical devices. To achieve on-demand and sophisticated shape morphing, the manufacture of structures with complex geometry and magnetization distribution is highly desired. Here, a magnetic dynamic polymer (MDP) composite composed of hard-magnetic microparticles in a dynamic polymer network with thermally responsive reversible linkages, which permits functionalities including targeted welding for magnetic-assisted assembly, magnetization reprogramming, and permanent structural reconfiguration, is reported. These functions not only provide highly desirable structural and material programmability and reprogrammability but also enable the manufacturing of functional soft architected materials such as 3D kirigami with complex magnetization distribution. The welding of magnetic-assisted modular assembly can be further combined with magnetization reprogramming and permanent reshaping capabilities for programmable and reconfigurable architectures and morphing structures. The reported MDP are anticipated to provide a new paradigm for the design and manufacture of future multifunctional assemblies and reconfigurable morphing architectures and devices.

Single phase e -Mn4N thin and ultrathin films are grown on MgO(001) using molecular beam epitaxy. Reflection high-energy electron diffraction and out-of-plane X-ray diffraction measurements are taken for each sample in order to determine the in- and out-of-plane strain for each sample. Vibrating sample magnetometry and superconducting quantum interference device measurements, which are performed on the thin and ultrathin films respectively, are used to plot the magnetization of each sample versus both in- and out-of-plane H → -fields and to determine the magnitude of perpendicular magnetic anisotropy in these films. Three significant components of perpendicular magnetic anisotropy are observed in these films and are attributed to sample strain (1 component) and shape (2 components). Among these components, the most significant component 0.8 – 4.9 Merg cm 3 is identified as a second term of shape anisotropy, which possesses a negative linear relationship with sample thickness over the range from 9 nm to 310 nm. Atomic (magnetic) force microscopy measurements show the presence of a surface localized magnetic polarization (22–82 % ), which increases with decreasing thickness, when the net magnetizations of the films are zero. The second term of shape anisotropy as well as the surface localized polarization, which each depend on sample thickness, are each regarded as a consequence of Ising domains overlapping out-of-plane in these films.

Partial discharge (PD) detection has been widely applied to high voltage cable systems for several decades. In this paper, three kinds of insulation defects in XLPE cables are designed and tested at step-wise DC voltage. The PD developing progress of each defect cable is divided into two stages based on the severity degree of PDs. Based on the compressed sensing (CS) theory, a novel method used for recognizing PD patterns at DC voltage is proposed. Firstly, both the statistical features of PD repetition rate and the norm characteristics of time domain features are extracted to create a high-dimensional feature space. Then each test sample from the feature space is sparsely represented as linear combinations of training samples, and the sufficiently sparse one is obtained via 1-norm minimization. Finally, the PD pattern can be recognized by minimizing the residuals between the test sample and the recovered one. The experimental data is analyzed by the proposed method, and the results show that the patterns of both PD source and PD stage are recognized precisely, when the combination solution of features and the 1-norm minimization algorithm are determined appropriately.

Implanted medical devices often transmit wireless signals to communicate with external equipment, but the efficiency of signal transmission is limited by internal reflection at the surface of the body. This work presents an approach to greatly enhance transmission, through the design of diffractive patterns capable of converting evanescent waves on the body's surface into waves propagating into the surrounding space. When printed on clothing and worn on the body, these patterns can increase the wireless signal's strength by nearly an order of magnitude, which may pave the way for longer-lasting and more functional bioelectronics.

Shape-programmable soft materials that exhibit integrated multifunctional shape manipulations, including reprogrammable, untethered, fast, and reversible shape transformation and locking, are highly desirable for a plethora of applications, including soft robotics, morphing structures, and biomedical devices. Despite recent progress, it remains challenging to achieve multiple shape manipulations in one material system. Here, a novel magnetic shape memory polymer composite is reported to achieve this. The composite consists of two types of magnetic particles in an amorphous shape memory polymer matrix. The matrix softens via magnetic inductive heating of low-coercivity particles, and high-remanence particles with reprogrammable magnetization profiles drive the rapid and reversible shape change under actuation magnetic fields. Once cooled, the actuated shape can be locked. Additionally, varying the particle loadings for heating enables sequential actuation. The integrated multifunctional shape manipulations are further exploited for applications including soft magnetic grippers with large grabbing force, reconfigurable antennas, and sequential logic for computing.

Magnetic-responsive composites that consist of a soft matrix embedded with hard-magnetic particles have recently been demonstrated as robust soft active materials for fast-transforming actuation. However, the deformation of the functional components commonly attains only a single actuation mode under external stimuli, which limits their capability of achieving tunable properties. To greatly enhance the versatility of soft active materials, we exploit a new class of programmable magnetic-responsive composites incorporated with a multifunctional joint design that allows asymmetric multimodal actuation under an external stimulation. We demonstrate that the proposed asymmetric multimodal actuation enables a plethora of novel applications ranging from the basic one-dimensional/two-dimensional (2D) active structures with asymmetric shape-shifting to biomimetic crawling robots, swimming robots with efficient dynamic performance, and 2D metamaterials with tunable properties. This new asymmetric multimodal actuation mechanism will open up new avenues for the design of next-generation multifunctional soft robots, biomedical devices, and acoustic metamaterials.

Molecular interactions between the active pharmaceutical ingredient and polymer have potentially substantial impacts on the physical stability of amorphous solid dispersions (ASDs), presumably by manipulating molecular mobility and miscibility. However, structural details for understanding the nature of the molecular contacts and mechanistic roles in various physicochemical and thermodynamic events often remain unclear. This study provides a spectroscopic characterization of posaconazole (POSA) formulations, a second-generation triazole antifungal drug (Noxafil, Merck & Co., Inc., Kenilworth, NJ, USA), at molecular resolution. One- and two-dimensional (2D) solid-state NMR (ssNMR) techniques including spectral editing, heteronuclear 1H-13C, 19F-13C, 15N-13C, and 19F-1H polarization transfer, and spin correlation and ultrafast magic angle spinning, together with the isotopic labeling strategy, were utilized to uncover molecular details in POSA ASDs in a site-specific manner. Active groups in triazole and difluorophenyl rings exhibited rich but distinct categories of interactions with two polymers, hypromellose acetate succinate and hypromellose phthalate, including intermolecular O-H···O═C and O-H···F-C hydrogen bonding, π-π aromatic packing, and electrostatic interaction. Interestingly, the chlorine-to-fluorine substituent in POSA, one of the major structural differences from itraconazole that could facilitate binding to the biological target, offers an additional contact with the polymer. These findings exhibit 2D ssNMR as a sensitive technique for probing sub-nanometer structures of pharmaceutical materials and provide a structural basis for optimizing the type and strength of drug-polymer interactions in the design of amorphous formulations.

The out-of-plane angular (${\ensuremath{\theta}}_{\mathrm{H}}$) dependence of the inverse spin Hall effect (ISHE) voltage (${V}_{\mathrm{ISHE}}$) generated by spin pumping has been investigated in ${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$ (YIG)/NiO/Pt trilayers. A simple sinusoidal angular dependence of ${V}_{\mathrm{ISHE}}$ has been viewed as a signature of spin pumping. Surprisingly, we observe an extensive plateau in the ${V}_{\mathrm{ISHE}}$ vs ${\ensuremath{\theta}}_{\mathrm{H}}$ plots with a pronounced peak feature at ${\ensuremath{\theta}}_{\mathrm{H}}\ensuremath{\sim}{45}^{\ensuremath{\circ}}$ to ${60}^{\ensuremath{\circ}}$ when the measurement temperature is close to the N\'eel temperature $({T}_{\mathrm{N}})$ of NiO. This phenomenon can be understood as arising from the competition between the exchange coupling at the YIG/NiO interface, the easy-plane and in-plane easy-axis anisotropies of NiO, and the effect of the applied magnetic field. While insulating antiferromagnetic films can efficiently transmit spin currents and show promise for integration in spintronic devices, the underlying physics of spin ordering and dynamics is richer than currently understood.

Electrical detection of topological magnetic textures such as skyrmions is currently limited to conducting materials. While magnetic insulators offer key advantages for skyrmion technologies with high speed and low loss, they have not yet been explored electrically. Here, we report a prominent topological Hall effect in Pt/Tm$_3$Fe$_5$O$_{12}$ bilayers, where the pristine Tm$_3$Fe$_5$O$_{12}$ epitaxial films down to 1.25 unit cell thickness allow for tuning of topological Hall stability over a broad range from 200 to 465 K through atomic-scale thickness control. Although Tm$_3$Fe$_5$O$_{12}$ is insulating, we demonstrate the detection of topological magnetic textures through a novel phenomenon: 'spin-Hall topological Hall effect' (SH-THE), where the interfacial spin-orbit torques allow spin-Hall-effect generated spins in Pt to experience the unique topology of the underlying skyrmions in Tm$_3$Fe$_5$O$_{12}$. This novel electrical detection phenomenon paves a new path for utilizing a large family of magnetic insulators in future skyrmion technologies.

Process-induced phase transformations (PIPTs) of active pharmaceutical ingredients (APIs) can alter APIs’ physicochemical properties and impact performance of pharmaceutical drug products. In this study, we investigated compression-induced amorphization of crystalline posaconazole (POSA), where the impact of mechanical stresses and excipients on amorphization were explored. 19F solid-state NMR (ssNMR) was utilized to detect and quantify amorphous content in the compressed tablets, and finite element analysis (FEA) was conducted to understand stress distributions in the compression process. Both applied macroscopic axial stress and shear stress were found to be important to amorphization of crystalline POSA. Punch velocity, an important compression process parameter, had negligible effect on amorphization up to 100 mm/s. Two diluents, microcrystalline cellulose (MCC) and dibasic calcium phosphate anhydrous (DCPA), and one lubricant, magnesium stearate (MgSt), were evaluated for their impact on amorphizatio...

Noncollinear antiferromagnet Mn3Sn has attracted wide interest as it is a candidate for Weyl semimetal. Here, we report the observation of topological Hall like signals in Mn3Sn/Pt bilayers grown on Al2O3(0001). X-ray diffraction and scanning transmission electron microscopy results confirm the high epitaxial quality of the c-axis-oriented Mn3Sn films. The detected topological Hall resistivity shows a broad temperature range from 210 to 365 K by tuning the thickness of Mn3Sn from 3 to 15 nm. Compared with previously reported topological Hall effects in Mn3Sn at temperatures below 50 K, the observed high-temperature topological Hall signal is likely due to the stabilization of topological spin textures enabled by the strong spin–orbit coupling of the Pt overlayer and the Dzyaloshinskii–Moriya interaction at the Mn3Sn/Pt interface.

Ferromagnetic resonance force microscopy (FMRFM) is a powerful scanned probe technique that uses sub-micrometer-scale, spatially localized standing spin wave modes (LMs) to perform local ferromagnetic resonance (FMR) measurements. Here, we show the spatially resolved imaging of Gilbert damping in a ferromagnetic material (FM) using FMRFM. Typically damping is measured from the FMR linewidth. We demonstrate an approach to image the spatial variation of Gilbert damping utilizing the LM resonance peak height to measure the LM resonance cone angle. This approach enables determination of damping through field-swept FMRFM at a single excitation frequency. The extreme force sensitivity of ∼2 fN at room temperature can resolve changes of Gilbert damping as small as ∼ 2 × 10 − 4 at 2 GHz, corresponding to ∼0.16 Oe in FMR linewidth resolution. This high sensitivity, high spatial resolution, and single frequency imaging of Gilbert damping creates the opportunity to study spin interactions at the interface between an insulating FM and a small volume of nonmagnetic material such as atomically thin two-dimensional materials.

Electrical and electronic experiment teaching is an indispensable and important part of engineering teaching. Oscilloscope is an indispensable experimental instrument in the teaching of these experiments, which is used to measure the electrical signals in the experimental process for analysis and processing. In this paper, a dual-channel virtual oscilloscope was designed based on the PC 16-bit sound card, which could correctly collect electronic signals within ±1V. Through LabVIEW graphical programming and multi-threading technology, these functions such as waveform display, channel selection control, parameter measurement and display, waveform storage and playback were realized. The innovation of this design is that it could automatically generate experimental report, simplifying the tedious operations such as drawing waveforms and filling parameters, finally quickly getting illustrated experimental report. From the test results, it can meet the requirements of daily experimental teaching, and it is of great significance to improve the quality of electrical and electronic experimental teaching.

The production of amorphous solid dispersions via hot melt extrusion (HME) relies on elevated temperature and prolonged residence time, which can result in potential degradation and decomposition of thermally sensitive components. Herein, the rheological properties of a physical mixture of polymer and an active pharmaceutical ingredient (API) were utilized to guide the selection of appropriate HME processing temperature. In the currently studied copovidone–nifedipine system, a critical temperature, which is substantially lower (∼13 °C) than the melting point of crystalline API, was captured during a temperature ramp examination and regarded as the critical point at which the API could molecularly dissolve into the polymer. Based on the identification of this critical point, various solid dispersions were prepared by HME processing below, at, and above the critical temperature (both below and above the melting temperature (Tm) of crystalline API). In addition, the resultant extrudates along with two contro...

The ordered double perovskites Sr2CrOsO6 and Ca2CrOsO6 have been synthesized and characterized with neutron powder diffraction, electrical transport measurements, and high field magnetization experiments. As reported previously Sr2CrOsO6 crystallizes with R 3 ¯ symmetry due to a−a−a− octahedral tilting. A decrease in the tolerance factor leads to a−a−b+ octahedral tilting and P21/n space group symmetry for Ca2CrOsO6. Both materials are found to be ferrimagnetic insulators with saturation magnetizations near 0.2 μB. Sr2CrOsO6 orders at 660 K while Ca2CrOsO6 orders at 490 K. Variable temperature magnetization measurements suggest that the magnetization of the Cr3+ and Os3+ sublattices have different temperature dependences in Sr2CrOsO6. This leads to a non-monotonic temperature evolution of the magnetic moment. Similar behavior is not seen in Ca2CrOsO6. Both compounds have similar levels of Os/Cr antisite disorder, with order parameters of η=80.2(4)% for Sr2CrOsO6 and η=76.2(5)% for Ca2CrOsO6, where η=2θ−1 and θ is the occupancy of the osmium ion on the osmium-rich Wyckoff site.

We report structural, surface, and magnetic investigations of ferromagnetic Ga-rich MnGa thin and ultra-thin films grown on semiconducting GaN(0001) using molecular beam epitaxy. The Mn:Ga composition ratio is varied from ≈1 (stoichiometric) to ≈0.42 (very Ga-rich) for different samples. We find that the L10 MnGa phase is preserved down to a Mn:Ga ratio of ≈0.81. As the Ga concentration increases, we observe the coexistence of more Ga-rich phases, namely Mn3Ga5 and Mn2Ga5. Room temperature scanning tunneling microscopy imaging reveals highly epitaxial films, with atomically smooth and highly reconstructed surfaces. Magnetic characterizations show how the magnetic properties evolve with changing composition and that giant perpendicular magnetic anisotropy is induced by reducing the size of our films.

This study aims to assess several model solid dispersions by using dynamic oscillatory rheology, solid-state NMR and other solid phase characterization techniques, and correlate their viscoelastic responses with processing methods and microstructures. A model active pharmaceutical ingredient (API), clotrimazole, was compounded with copovidone to form solid dispersions via various techniques with different mixing capabilities. Physicochemical characterizations of the resulting solid dispersions demonstrated that simple physical mixing led to a poorly mixed blend manifested by existence of large API crystalline content and heterogeneous distribution. Cryogenic milling significantly improved mixing of two components as a result of reduced particle size and increased contact surface area, but produced limited amorphous content. In contrast, hot melt extrusion (HME) processing resulted in a homogenous amorphous solid dispersion because of its inherent mixing efficiency. Storage modulus and viscosities versus frequency of different solid dispersions indicated that the incorporation of API into the polymer matrix resulted in a plasticizing effect which reduced the viscosity. The crystalline/aggregated forms of API also exhibited more elastic response than its amorphous/dispersed counterpart. Temperature ramps of the physical mixture with high API concentration captured a critical temperature, at which a bump was observed in damping factor. This bump was attributed to the dissolution of crystalline API into the polymer. In addition, heating-cooling cycles of various solid dispersions suggested that cryomilling and HME processing could form a homogeneous solid dispersion at low API content, whereas high drug concentration led to a relatively unstable dispersion due to supersaturation of API in the polymer.

Acoustic metamaterials have subwavelength characteristics and hence they can be used for the low-frequency noise and vibration control. Usually, acoustic metamaterials have constant material properties and their dynamic responses are difficult to tune once manufactured, resulting in a fixed and narrow working band and limiting the number of possible applications. In this paper, by mean of elastomeric matrix with a square array of circular holes and resonating elements (including elastomeric coating and resonating mass), we design a new kind of tunable acoustic metamaterials with resonating elements embedded into the elastomeric matrix. Under equibiaxial compression, the deformation induced geometry and material nonlinearities of the elastomeric matrix and coating are intentionally exploited to tune the dynamic responses of acoustic metamaterials. We numerically investigate the stress–strain curves of the elastomeric matrix and coating, and the evolution of band gaps during deformation. Furthermore, the transmissions of the finite-sized acoustic metamaterial structures in the undeformed and deformed configurations are calculated to verify the tunability of the band structures. The numerical results indicate the locally resonant and Bragg scattering band gaps can be simultaneously controlled by deformation. The primitive low-frequency locally resonant band gap at 0.197 ∼ 0.226 is shifted and widened to 0.168 ∼ 0.364 in the deformed configuration and the width of band gap is increased 7.76 times, which provide a useful guideline for the low-frequency noise and vibration control.

We studied exchange bias and exchange spring effects in magnetic bilayer thin films of Fe and CrN grown by molecular beam epitaxy. First, the relationships between exchange bias, coercivity, and blocking temperature and the Fe and CrN layers thicknesses are studied. Second, the exchange spring effect is observed and studied in all samples. The exchange spring breaks free at critical applied field strengths while creating planar domain walls at lower applied fields. First-principles calculations are performed to understand the magnetic interactions between the Fe and CrN layers at their interfaces. The calculations are key to understanding the experimental observations.

Since ancient Greece, handshaking has been commonly practiced between two people as a friendly gesture to express trust and respect, or form a mutual agreement. In this paper, we show that such physical contact can be used to bootstrap secure cyber contact between the smart devices worn by users. The key observation is that during handshaking, although belonged to two different users, the two hands involved in the shaking events are often rigidly connected, and therefore exhibit very similar motion patterns. We propose a novel Shake-n-Shack system, which harvests motion data during user handshaking from the wrist worn smart devices such as smartwatches or fitness bands, and exploits the matching motion patterns to generate symmetric keys on both parties. The generated keys can be then used to establish a secure communication channel for exchanging data between devices. This provides a much more natural and user-friendly alternative for many applications, e.g. exchanging/sharing contact details, friending on social networks, or even making payments, since it doesn't involve extra bespoke hardware, nor require the users to perform pre-defined gestures. We implement the proposed Shake-n-Shack system on off-the-shelf smartwatches, and extensive evaluation shows that it can reliably generate 128-bit symmetric keys just after around 1s of handshaking (with success rate >99%), and is resilient to real-time mimicking attacks: in our experiments the Equal Error Rate (EER) is only 1.6% on average. We also show that the proposed Shake-n-Shack system can be extremely lightweight, and is able to run in-situ on the resource-constrained smartwatches without incurring excessive resource consumption., To appear in PerCom'18

Integrating wireless technologies with implanted devices could enable important capabilities for medicine. However, existing wireless systems suffer from low efficiency of energy transmission from the human body owing to the mismatch between the dielectric properties of the body and that of freespace. We present an approach to enhance wireless transmission from the body by modifying the air-tissue interface with an electromagnetic grating. The grating enables the radiation of wave components otherwise trapped by total internal reflection into the far-field and increases the total power radiated into free-space space. We show in simulations that the grating can enhance transmission by a factor of 3 and propose methods for implementing such a device in a clinical setting.

In the context of the theory of multiple intelligences, this article focuses on the relationship between music intelligence and other intelligences such as power grids and electrical appliances, discusses the role of music education in smart overall development, and briefly analyzes how music education integrates with other subject teaching and cooperative teaching of interdisciplinary.

Spin currents are generated within the bulk of magnetic materials due to heat flow, an effect called intrinsic spin-Seebeck. This bulk bosonic spin current consists of a diffusing thermal magnon cloud, parametrized by the magnon chemical potential ($\mu_{m}$), with a diffusion length of several microns in yttrium iron garnet (YIG). Transient opto-thermal measurements of the spin-Seebeck effect (SSE) as a function of temperature reveal the time evolution of $\mu_{m}$ due to intrinsic SSE in YIG. The interface SSE develops at times < 2 ns while the intrinsic SSE signal continues to evolve at times > 500 $\mu$s, dominating the temperature dependence of SSE in bulk YIG. Time-dependent SSE data are fit to a multi-temperature model of coupled spin/heat transport using finite element method (FEM), where the magnon spin lifetime ($\tau$) and magnon-phonon thermalization time ($\tau_{mp}$) are used as fit parameters. From 300 K to 4 K, $\tau_{mp}$ varies from 1 to 10 ns, whereas $\tau$ varies from 2 to 60 $\mu$s with the spin lifetime peaking at 90 K. At low temperature, a reduction in $\tau$ is observed consistent with impurity relaxation reported in ferromagnetic resonance measurements. These results demonstrate that the thermal magnon cloud in YIG contains extremely low frequency magnons (~10 GHz) providing spectral insight to the microscopic scattering processes involved in magnon spin/heat diffusion., Comment: 35 pages and 17 figures

An emerging class of targeted therapy relies on light as a spatially and temporally precise stimulus. Photodynamic therapy (PDT) is a clinical example in which optical illumination selectively activates light-sensitive drugs, termed photosensitizers, destroying malignant cells without the side effects associated with systemic treatments such as chemotherapy. Effective clinical application of PDT and other light-based therapies, however, is hindered by challenges in light delivery across biological tissue, which is optically opaque. To target deep regions, current clinical PDT uses optical fibers, but their incompatibility with chronic implantation allows only a single dose of light to be delivered per surgery. Here we report a wireless photonic approach to PDT using a miniaturized (30 mg, 15 mm3) implantable device and wireless powering system for light delivery. We demonstrate the therapeutic efficacy of this approach by activating photosensitizers (chlorin e6) through thick (>3 cm) tissues inaccessible by direct illumination, and by delivering multiple controlled doses of light to suppress tumor growth in vivo in animal cancer models. This versatility in light delivery overcomes key clinical limitations in PDT, and may afford further opportunities for light-based therapies.

Temperature-dependent spin Seebeck effect data on Pt|yttrium iron garnet (YIG) (${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$)|gallium gadolinium garnet ($\mathrm{G}{\mathrm{d}}_{3}\mathrm{G}{\mathrm{a}}_{5}{\mathrm{O}}_{12}$) are reported for YIG films of various thicknesses. The effect is reported as a spin Seebeck resistivity (SSR), the inverse spin-Hall field divided by the heat flux, to circumvent uncertainties about temperature gradients inside the films. The SSR is a nonmonotonic function of YIG thickness. A diffusive model for magnon transport demonstrates how these data give evidence for the existence of two distinct length scales in thermal spin transport, a spin-diffusion length, and a magnon energy relaxation length.

High-harmonic generation from gases produces attosecond bursts and enables high-harmonic spectroscopy to explore electron dynamics in atoms and molecules. Recently, high-harmonic generation from solids has been reported, resulting in novel phenomena and unique control of the emission, absent in gas-phase media. Here we investigate high harmonics from semiconductors with controllable induced photo-carrier densities, as well as the driving wavelengths. We demonstrate that the dominant generation mechanism can be identified by monitoring the variation of the harmonic spectra with the carrier density. Moreover, the harmonic spectral dependence on the driving wavelength is reported and a different dependence from the well-known one in gas-phase media is observed. Our study provides distinct control of the harmonic process from semiconductors, sheds light on the underlying mechanism and helps optimize the harmonic properties for future solid-state attosecond light sources., The properties of high harmonic generation from solids are not fully understood. Here, Wang et al. control the photo-carriers injected in a semiconductor to distinguish interband and intraband contributions to different high harmonics, and investigate the wavelength dependence of the harmonics.

Low-damping magnetic materials have been widely used in microwave and spintronic applications because of their low energy loss and high sensitivity. While the Gilbert damping constant can reach 10−4 to 10−5 in some insulating ferromagnets, metallic ferromagnets generally have larger damping due to magnon scattering by conduction electrons. Meanwhile, low-damping metallic ferromagnets are desired for charge-based spintronic devices. Here, we report the growth of Co25Fe75 epitaxial films with excellent crystalline quality evident by the clear Laue oscillations and exceptionally narrow rocking curve in the X-ray diffraction scans as well as from scanning transmission electron microscopy. Remarkably, the Co25Fe75 epitaxial films exhibit a damping constant, Owing to their conductivity, low-damping metallic ferromagnets are preferred to insulating ferromagnets in charge-based spintronic devices, but are not yet well developed. Here the authors achieve low magnetic damping in CoFe epitaxial films which is comparable to conventional insulating ferromagnetic YIG films.

Low-loss magnetization dynamics and strong magnetoelastic coupling are generally mutually exclusive properties due to opposing dependencies on spin-orbit interactions. So far, the lack of low-damping, magnetostrictive ferrite films has hindered the development of power-efficient magnetoelectric and acoustic spintronic devices. Here, magnetically soft epitaxial spinel NiZnAl-ferrite thin films with an unusually low Gilbert damping parameter (