Realization of skyrmion shift register.

The big data explosion demands novel data storage technology. Among many different approaches, solitonic racetrack memory devices hold great promise for accommodating nonvolatile and low-power functionalities. As representative topological solitons, magnetic skyrmions are envisioned as potential information carriers for efficient information processing. While their advantages as memory and logic elements have been vastly exploited from theoretical perspectives, the corresponding experimental efforts are rather limited. These challenges, which are key to versatile skyrmionic devices, will be studied in this work. Through patterning concaved surface topography with designed arrays of indentations on standard Si/SiO2 substrates, we demonstrate that the resultant non-flat energy landscape could lead to the formation of hexagonal and square skyrmion lattices in Ta/CoFeB/MgO multilayers. Based on these films, one-dimensional racetrack devices are subsequently fabricated, in which a long-distance deterministic shifting of skyrmions between neighboring indentations is achieved at room temperature. Through separating the word line and the bit line, a prototype shift register device, which can sequentially generate and precisely shift complex skyrmionic data strings, is presented. The deterministic writing and long-distance shifting of skyrmionic bits can find potential applications in transformative skyrmionic memory, logic as well as the in-memory computing devices.

Distinguishing artificial spin ice states using magnetoresistance effect for neuromorphic computing.

Artificial spin ice (ASI) consisting patterned array of nano-magnets with frustrated dipolar interactions offers an excellent platform to study frustrated physics using direct imaging methods. Moreover, ASI often hosts a large number of nearly degenerated and non-volatile spin states that can be used for multi-bit data storage and neuromorphic computing. The realization of the device potential of ASI, however, critically relies on the capability of transport characterization of ASI, which has not been demonstrated so far. Using a tri-axial ASI system as the model system, we demonstrate that transport measurements can be used to distinguish the different spin states of the ASI system. Specifically, by fabricating a tri-layer structure consisting a permalloy base layer, a Cu spacer layer and the tri-axial ASI layer, we clearly resolve different spin states in the tri-axial ASI system using lateral transport measurements. We have further demonstrated that the tri-axial ASI system has all necessary required properties for reservoir computing, including rich spin configurations to store input signals, nonlinear response to input signals, and fading memory effect. The successful transport characterization of ASI opens up the prospect for novel device applications of ASI in multi-bit data storage and neuromorphic computing.

Antiferromagnetic Inverse Spin Hall Effect.

The inverse spin Hall effect (ISHE) is one of the accessible and reliable methods to detect spin current. The magnetization-dependent inverse spin Hall effect has been observed in magnets, expanding the dimension for spin-to-charge conversion. However, antiferromagnetic Néel-vector-dependent ISHE, which has been long time highly pursued, is still elusive. Here, ISHE in Mn2 Au/[Co/Pd] heterostructures is investigated by terahertz emission and spin Seebeck effect measurements, where [Co/Pd] possesses perpendicular magnetic anisotropy for out-of-plane polarized spin current generation and Mn2 Au is a collinear antiferromagnet for the spin-to-charge conversion. The out-of-plane spin polarization (σz ) is rotated toward in-plane by the Néel vectors in Mn2 Au, then the spin current is converted into charge current at two staggered spin sublattices. The ISHE signal is much stronger when the converted charge current is parallel to the Néel vector compared with its orthogonal counterpart. The Néel vector and resultant ISHE signals, which is termed as antiferromagnetic inverse spin Hall effect, can be switched. The finding not only adds a new member to the Hall effect family, but also makes antiferromagnetic spintronics more flexible.

National Rare Diseases Registry System (NRDRS): China's first nation-wide rare diseases demographic analyses.

BACKGROUND: China has made tremendous progresses in serving the needs of its people living with rare diseases in the past decade, especially over the last 5 years. The Chinese government's systematic approach included a series of coordinated initiatives, amongst these are: forming the Rare Disease Expert Committee (2016), funding the "Rare Diseases Cohort Study" (2016-2020), and publishing its first "Rare Disease Catalog" (2018). Herein, we present the National Rare Diseases Registry System (NRDRS)-China's first national rare diseases registry, and the analysis of cases registered in the first 5 years ending Dec 31, 2020. RESULTS: The total 62,590 cases covered 166 disease/disease types, forming 183 disease cohorts. The data from nearly 22% of them (13,947 cases) is also linked to valuable biological samples. The average age of definitive diagnosis was 30.88 years; 36.07% of cases were under 18 years of age. Regional distribution analysis showed 60% of cases were from the more developed, wealthier East and North China, suggesting the local availability of quality care and patients' financial status were key access factors. Finally, 82.04% of cases were registered from the five clinical departments: Neurology, Endocrine, Hematology, Cardiovascular, and Nephrology, suggesting that either these are most affected by rare diseases, or that there were disease non-specific ascertainment factors. CONCLUSIONS: The preliminary analysis of the first 5-year's data provides unique and valuable insight on rare disease distribution in China, and higlights the directions for enhancing equity, scale and utility.

Effect of tannin addition on chromatic characteristics, sensory qualities and antioxidant activities of red wines.

Tannin addition as an enological practice has been widely used in the winemaking process because of their ability of improving the aroma and sensory characteristics and stabilizing of color of red wine. In this study, hydrolysable, condensed tannins and their mixtures in different ratios were added into two Merlot wines to investigate their effect on the wine overall quality. The contents of 15 phenolic compounds were detected by HPLC-DAD, CIELAB color parameters were measured using a chromatic aberration meter, sensory evaluation was accomplished using the assessment standards established by the American Wine Association, and antioxidant activities were analyzed using DPPH and ABTS radical tests. The results indicated that adding tannins affected phenolic composition, contents and color of wine. The specific effects varied by tannins. Furthermore, tannin addition, especially the mixed tannins, improved the sensory qualities and antioxidant activities greatly. The mixed tannins added with a ratio of 1 : 1 between hydrolyzable and condensed tannins exhibited a better effect on both sensory qualities and antioxidant activities, and it could be recommended as an ideal tannin addition for wine quality improvement.

Prediction of Attractive Level Crossing via a Dissipative Mode.

The new field of spin cavitronics focuses on the interaction between the magnon excitation of a magnetic element and the electromagnetic wave in a microwave cavity. In the strong interaction regime, such an interaction usually gives rise to the level anticrossing for the magnonic and the electromagnetic mode. Recently, the attractive level crossing has been observed, and it is explained by a non-Hermitian model Hamiltonian. However, the mechanism of such attractive coupling is still unclear. We reveal the secret by using a simple model with two harmonic oscillators coupled to a third oscillator with large dissipation. We further identify this dissipative third party as the invisible cavity mode with large leakage in cavity-magnon experiments. This understanding enables one to design dissipative coupling in all sorts of coupled systems.

A semisynthetic approach for the simultaneous reaction of grape seed polymeric procyanidins with catechin and epicatechin to obtain oligomeric procyanidins in large scale.

Polymeric procyanidins (PPCs) were the major constituents of procyanidins, while they have poor bioactivity. To better utilize PPCs, a semisynthetic approach for converting PPCs to oligomeric procyanidins (OPCs) was proposed. Grape seed PPCs were simultaneously reacted with catechin (C) and epicatechin (EC) under acid condition. Combining response surface methodology (RSM) and single-factor experiments, an optimized semisynthetic condition was confirmed with the ratio of PPCs with C and EC of 1:1:1, temperature of 40 °C, reaction time of 20 min and 0.1 M methanolic HCl. High-speed counter-current chromatography (HSCCC) was adopted to obtain three fractions from semisynthetic products and preparative-HPLC was used to isolate individual procyanidins. Thirteen B-type procyanidins including monomers, dimers and trimers were got with high yield of 0.8-17.8 mg from 200 mg semisynthetic products and high purity over 91%. The developed semisynthesis combined with separation method was efficient to obtain individual OPCs in preparative scale.

Unexpected Intermediate State Photoinduced in the Metal-Insulator Transition of Submicrometer Phase-Separated Manganites.

At ultrafast timescales, the initial and final states of a first-order metal-insulator transition often coexist forming clusters of the two phases. Here, we report an unexpected third long-lived intermediate state emerging at the photoinduced first-order metal-insulator transition of La_{0.325}Pr_{0.3}Ca_{0.375}MnO_{3}, known to display submicrometer length-scale phase separation. Using magnetic force microscopy and time-dependent magneto-optical Kerr effect, we determined that the third state is a nanoscale mixture of the competing ferromagnetic metallic and charge-ordered insulating phases, with its own physical properties. This discovery bridges the two different families of colossal magnetoresistant manganites known experimentally and shows for the first time that the associated states predicted by theory can coexist in a single sample.

Antiferromagnetic domain wall as spin wave polarizer and retarder.

As a collective quasiparticle excitation of the magnetic order in magnetic materials, spin wave, or magnon when quantized, can propagate in both conducting and insulating materials. Like the manipulation of its optical counterpart, the ability to manipulate spin wave polarization is not only important but also fundamental for magnonics. With only one type of magnetic lattice, ferromagnets can only accommodate the right-handed circularly polarized spin wave modes, which leaves no freedom for polarization manipulation. In contrast, antiferromagnets, with two opposite magnetic sublattices, have both left and right-circular polarizations, and all linear and elliptical polarizations. Here we demonstrate theoretically and confirm by micromagnetic simulations that, in the presence of Dzyaloshinskii-Moriya interaction, an antiferromagnetic domain wall acts naturally as a spin wave polarizer or a spin wave retarder (waveplate). Our findings provide extremely simple yet flexible routes toward magnonic information processing by harnessing the polarization degree of freedom of spin wave.Spin waves are promising candidates as carriers for energy-efficient information processing, but they have not yet been fully explored application wise. Here the authors theoretically demonstrate that antiferromagnetic domain walls are naturally spin wave polarizers and retarders, two key components of magnonic devices.

Emerging single-phase state in small manganite nanodisks.

In complex oxides systems such as manganites, electronic phase separation (EPS), a consequence of strong electronic correlations, dictates the exotic electrical and magnetic properties of these materials. A fundamental yet unresolved issue is how EPS responds to spatial confinement; will EPS just scale with size of an object, or will the one of the phases be pinned? Understanding this behavior is critical for future oxides electronics and spintronics because scaling down of the system is unavoidable for these applications. In this work, we use La0.325Pr0.3Ca0.375MnO3 (LPCMO) single crystalline disks to study the effect of spatial confinement on EPS. The EPS state featuring coexistence of ferromagnetic metallic and charge order insulating phases appears to be the low-temperature ground state in bulk, thin films, and large disks, a previously unidentified ground state (i.e., a single ferromagnetic phase state emerges in smaller disks). The critical size is between 500 nm and 800 nm, which is similar to the characteristic length scale of EPS in the LPCMO system. The ability to create a pure ferromagnetic phase in manganite nanodisks is highly desirable for spintronic applications.

Synthesis and growth mechanism of selenium nanowire bundles via a polymer-controlled chemical route.

This article describes a polymer-controlled chemical method for synthesis of trigonal selenium (t-Se) nanowire bundles in the presence of poly(vinyl alcohol) (PVA) at 100 degrees C. Electron microscope images show that Se nanowires have diameters of 30-50 nm and lengths of up to a few tens of micrometers. TEM images display the direct evidence for the growth process of single-crystalline Se nanowire bundles, which suggested that Se nanowire bundles were directly converted from the initial amorphous Se micro-particles in the presence of PVA. UV-Vis absorbance of t-Se nanowire bundles revealed that the bandgap and absorbance peaks displayed larger blue shifts relative to those of bulk t-Se.

Large-scale hydrothermal synthesis of SnS2 nanobelts.

SnS2 nanobelts were successfully synthesized through a controllable solution-phase hydrothermal method on a large scale. The nanobelts have a very high yield, which is more than 95%, with widths ranging from 100 to 200 nanometers, lengths up to several micrometers and thicknesses ca. 10 nanometers. X-ray diffraction patterns, electronic diffraction, X-ray photoelectron spectra, field emission scanning electron microscopy images, transmission electron microscopy images and high-resolution transmission electron microscopy investigated the phase structures, compositions, and morphologies of SnS2 nanobelts. Dodecanethiol played important roles in the process of SnS2 nanobelts formation and growth. The formation mechanism of SnS2 nanobelts was investigated and discussed on the basis of the experimental results.

Ni11As8 single-crystalline nanosheets via hydrothermal redox route.

Ni11As8 crystallites 23-nm thick and 250-700-nm wide in lateral dimension were prepared in alkaline hydrothermal condition. Transmission electron microscope (TEM) images and selected area electron diffraction (SAED) analyses showed that the as-prepared Ni11As8 was single-crystalline nanosheets of [331] orientation. The Ni11As8 exhibited an optical absorption onset of 3.00 eV in the visible spectral regime. Its magnetic measurement indicated a weak magnetic hysteresis and unsaturation magnetization with a magnetic susceptibility of 1.37 x 10(-4) cm3/g (at 15 kOe) at room temperature, the origin of which was discussed and assigned to the effect of surface species containing Ni ions. The extended Hückel tight-binding calculation revealed that bulk Ni11As8 has a 3d-localized narrow band below Fermi level and complicated band structure with small band gap in the first Brillouin zone, which supply clues to explain the observed optical and magnetic properties. The formation mechanism of Ni11As8 was studied and attributed to an alkaline hydrothermal redox route on the basis of the Marsh reaction.

Hydrothermal growth and optical properties of doughnut-shaped ZnO microparticles.

Doughnut-shaped ZnO microparticles have been grown through a hydrothermal reaction in citrate solution at 120 degrees C. FESEM reveals that these microparticles consist of regular arranged nanoplates, and there is a concave on the surface of each microparticle. The existence of citrate is vital to the formation of the complex microparticles. Room temperature photoluminescence measurements show strong UV band emission. The yellow and green emissions related to the structure defects can be barely observed, indicating the high crystalline perfection of these microparticles.

Hydrothermal route to InAs semiconductor nanocrystals.

Spherical InAs nanocrystals of 30-50 nm were hydrothermally synthesized at 120 degrees C, which showed a 100 meV-blueshift of band gap absorption and phonon confinement of optical vibration mode. The study of hydrothermal formation mechanism indicated that crystalline InAs could be obtained in an extended pH range (approximately -0.15 to 14).

Large-scale synthesis of carbon nanotubes by an ethanol thermal reduction process.

The bamboo-shaped carbon nanotubes were synthesized on a large scale through an ethanol thermal reduction process, in which ethanol was used as the carbon source and magnesium was used as the reductant. The toxic or corrosive reagents have been completely avoided. Furthermore, Y-junction carbon nanotubes obtained from our experiment can be used as the building blocks of nanoelectronics. Because of the simplicity and high yield of this route, it may potentially be applied on the scale of industrial production.