Determinants of regioselectivity of heterostructures in cation exchange reactions.

A cation exchange (CE) reaction offers a remarkable opportunity to create versatile metal sulfide nanocrystals (NCs) with arbitrary complexity in composition, structure, and functionality. The concept of regioselectivity has been discovered and developed to build the target heterostructures through CE reactions, yet a general principle of regioselectivity remains unclear. In this work, we establish connections between experimental results and theoretical insights to elucidate the determinants of regioselectivity using designed aliovalent CE reactions on a two-dimensional template.

On hyper-parameter selection for guaranteed convergence of RMSProp.

RMSProp is one of the most popular stochastic optimization algorithms in deep learning applications. However, recent work has pointed out that this method may not converge to the optimal solution even in simple convex settings. To this end, we propose a time-varying version of RMSProp to fix the non-convergence issues.

Template Selection Strategy for Synthesis of One-Dimensional CrSbSe Ferromagnetic Semiconductor Nanoribbons.

CrSbSe─the only experimentally validated one-dimensional (1D) ferromagnetic semiconductor─has recently attracted significant attention. However, all reported synthesis methods for CrSbSe nanocrystals are based on top-down methods. Here we report a template selection strategy for the bottom-up synthesis of CrSbSe nanoribbons.

Hypervolume Niche Dynamics and Global Invasion Risk of under Climate Change.

As a globally invasive quarantine pest, the cotton mealybug, , is spreading rapidly, posing serious threats against agricultural and forestry production and biosecurity. In recent years, the niche conservatism hypothesis has been widely debated, which is particularly evident in invasive biology research. Identifying the niche dynamics of , as well as assessing its global invasion risk, is of both theoretical and practical importance.

Strain-tunable magnetism and topological states in layered VBiTe.

Similar to the magnetic topological insulator of MnBiTe, recent studies have demonstrated that VBiTe is also an ideal candidate to explore many intriguing quantum states. Different from the strong interlayer antiferromagnetic (AFM) coupling in layered MnBiTe, based on first-principles calculations, we find that the energy difference between AFM and ferromagnetic (FM) orders in layered VBiTe is much smaller than that of MnBiTe. Specifically, it is found that the interlayer FM coupling can be readily achieved by applying strain.

Engineering topological states in a two-dimensional honeycomb lattice.

In this work, we use first-principles calculations to determine the interplay between spin-orbit coupling (SOC) and magnetism which can not only generate a quantum anomalous Hall state but can also result in topologically trivial states although some honeycomb systems host large band gaps. By employing tight-binding model analysis, we have summarized two types of topologically trivial states: one is due to the coexistence of quadratic non-Dirac and linear Dirac bands in the same spin channel that act together destructively in magnetic materials (such as, CrBr, CrCl, and VBr monolayers); the other one is caused by the destructive coupling effect between two different spin channels due to small magnetic spin splitting in heavy-metal-based materials, such as, BaTe(111)-supported plumbene. Further investigations reveal that topologically nontrivial states can be realized by removing the Dirac band dispersion of the magnetic monolayers for the former case (such as in alkali metal doped CrBr), while separating the two different spin channels from each other by enhancing the magnetic spin splitting for the latter case (such as in half-iodinated silicene).

Multidimensional climatic niche conservatism and invasion risk of .

The cotton mealybug , a globally invasive insect, is listed as a national quarantine pest in agriculture and forestry, which seriously threatens biological safety of China. Niche conservatism is a key assumption of species distribution model. An evaluation of the applicability of using ecological niche models to assess the invasion risk of cotton mealybug, and further optimizing model complexity, are of both theoretical and practical significance.

BiTe-intercalated MnBiTe: ideal candidate to explore intrinsic Chern insulator and high-temperature quantum anomalous Hall effect.

The recently discovered magnetic topological insulator of MnBiTe(MBT), has been demonstrated to realize the quantum anomalous Hall (QAH) effect, while the naturally antiferromagnetic (AFM) interlayer coupling in MBT results in that the QAH effect can only be realized in odd-layered systems and at low temperature. Using first-principles calculations, we find that intercalating BiTe(BT) layers into MBT by forming MBT/(BT)/MBT (= 1-6) heterostructures can induce magnetic phase transition from AFM to ferromagnetic (FM) interlayer coupling when⩾ 3. Specifically, MBT/(BT)/MBT and MBT/(BT)/MBT respectively host Curie temperaturesof 14 K and 11 K, which fits well the experimentally measuredof 12 K.

Iterative List Patterned Reed-Muller Projection Detection-Based Packetized Unsourced Massive Random Access.

In this paper, we consider a slot-controlled coded compressed sensing protocol for unsourced massive random access (URA) that concatenates a shared patterned Reed-Muller (PRM) inner codebook to an outer error-correction code. Due to the limitations of the geometry-based decoding algorithm in single-sequence settings and due to the message interference that may result in decreased decoding performance under multi-sequence circumstances, a list PRM projection algorithm and an iterative list PRM projection algorithm are proposed to supplant the signal detector associated with the inner PRM sequences in this paper. In detail, we first propose an enhanced path-saving algorithm, called list PRM projection detection, for use in single-user scenarios that maintains multiple candidates during the first few layers so as to remedy the risk of spreading errors.

Patterned Reed-Muller Sequences with Outer A-Channel Codes and Projective Decoding for Slot-Controlled Unsourced Random Access.

We propose a novel slot-pattern-control based coded compressed sensing for unsourced random access with an outer A-channel code capable of correcting errors. Specifically, an RM extension code called patterned Reed-Muller (PRM) code is proposed. We demonstrate the high spectral efficiency due to its enormous sequence space and prove the geometry property in the complex domain that enhances the reliability and efficiency of detection.

Growth of single-crystal black phosphorus and its alloy films through sustained feedstock release.

Black phosphorus (BP), a fascinating semiconductor with high mobility and a tunable direct bandgap, has emerged as a candidate beyond traditional silicon-based devices for next-generation electronics and optoelectronics. The ability to grow large-scale, high-quality BP films is a prerequisite for scalable integrated applications but has thus far remained a challenge due to unmanageable nucleation events. Here we develop a sustained feedstock release strategy to achieve subcentimetre-size single-crystal BP films by facilitating the lateral growth mode under a low nucleation rate.

Synthesis of Indolizines TfO-Mediated Cascade Reaction of Pyridyl-enaminones with Thiophenols/Thioalcohols.

A cost-effective, highly regioselective and metal-free version for the synthesis of indolizine derivatives by means of TfO-mediated cascade reaction of pyridyl-enaminones and thiophenols/thioalcohols under mild reaction conditions has been reported. Diverse electron-rich indolizine derivatives could be obtained in up to 94% yield the selective 1,4-addition of vinyl iminium triflate tandem cyclization/aromatization, which allowed the simultaneous construction of C-N and C-S/and one example of C-Se bonds.

Emergent, Non-Aging, Extendable, and Rechargeable Exchange Bias in 2D Fe GeTe Homostructures Induced by Moderate Pressuring.

As a crucial concept in magnetism and spintronics, exchange bias (ExB) measures the asymmetry in the hysteresis loop of a pinned ferromagnet (FM)/antiferromagnet (AFM) interface. Previous studies are mainly focused on FM/AFM heterostructures composed of conventional bulk materials, whose complex interfaces prohibit precise control and full understanding of the phenomenon. Here, the enabling power of 2D magnets is exploited to demonstrate the emergence, non-aging, extendability, and rechargeability of ExB in van der Waals Fe GeTe homostructures, upon moderate pressuring.

A generic dual d-band model for interlayer ferromagnetic coupling in a transition-metal doped MnBiTe family of materials.

Realization of ferromagnetic (FM) interlayer coupling in magnetic topological insulators (TIs) of the MnBiTe family of materials (MBTs) may pave the way for realizing the high-temperature quantum anomalous Hall effect (high- QAHE). Here we propose a generic dual d-band (DDB) model to elucidate the energy difference (Δ = - ) between the AFM and FM coupling in transition-metal (TM)-doped MBTs, where the valence of TMs splits into d-t and d-e sub-bands. Remarkably, the DDB shows that Δ is universally determined by the relative position of the dopant (X) and Mn d-e/ bands, .

Periodic analysis on gas path fault diagnosis of gas turbines.

The gas path fault diagnosis is considered widely to ensure the economy, safety and practicability of gas turbines. Traditional gas path diagnosis methods are vulnerable to various uncertainties, resulting in a deviation between the diagnostic results and the real states, which brings huge potential safety hazard to industrial production. Periodic analysis can suppress the uncertainty interference and extract accurately the features of performance parameters to improve the accuracy of health evaluation.

Inverse association between body mass index and all-cause mortality in rural chinese adults: 15-year follow-up of the Anqing cohort study.

Objective: To investigate the association between body mass index (BMI) and all-cause mortality in a Chinese rural population.

Design: Prospective cohort study.

Setting: This study was conducted from 2003 to 2018 in Anqing, Anhui Province, China.

One-Pot Synthesis Enables Magnetic Coupled CrTe/MnTe/CrTe Integrated Heterojunction Nanorods.

Magnetic heterostructures offer great promise in spintronic devices due to their unique magnetic properties, such as exchange bias effect, topological superconductivity, and magneto-resistance. Although various magnetic heterostructures including core/shell, multilayer, and van der Waals systems have been fabricated recently, the construction of perfect heterointerfaces usually rely on complicated and high-cost fabrication methods such as molecular-beam epitaxy; surprisingly, few one-dimensional (1D) bimagnetic heterojunctions, which provide multidegrees of freedom to modulate magnetic properties via magnetic anisotropy and interface coupling, have been fabricated to date. Here we report a one-pot solution-based method for the synthesis of ferromagnetic/antiferromagnetic/ferromagnetic heterojunction nanorods with excellent heterointerfaces in the case of CrTe/MnTe/CrTe.

Selective Substrate-Orbital-Filtering Effect to Realize the Large-Gap Quantum Spin Hall Effect.

Although Pb harbors a strong spin-orbit coupling effect, pristine plumbene (the last group-IV cousin of graphene) hosts topologically trivial states. Based on first-principles calculations, we demonstrate that epitaxial growth of plumbene on the BaTe(111) surface converts the trivial Pb lattice into a quantum spin Hall (QSH) phase with a large gap of ∼0.3 eV via a substrate-orbital-filtering effect.

Cigarette smoking and all-cause mortality in rural Chinese male adults: 15-year follow-up of the Anqing cohort study.

Background: According to the Global Burden of Disease Study 2017, smoking is one of the leading four risk factors contributing to deaths in China. We aimed to evaluate the associations of smoking with all-cause mortality in a Chinese rural population.

Methods: Male participants over age 45 (n = 5367) from a large familial aggregation study in rural China, were included in the current analyses.

Convergence of the RMSProp deep learning method with penalty for nonconvex optimization.

A norm version of the RMSProp algorithm with penalty (termed RMSPropW) is introduced into the deep learning framework and its convergence is addressed both analytically and numerically. For rigour, we consider the general nonconvex setting and prove the boundedness and convergence of the RMSPropW method in both deterministic and stochastic cases. This equips us with strict upper bounds on both the moving average squared norm of the gradient and the norm of weight parameters throughout the learning process, owing to the penalty term within the proposed cost function.

Binary and Ternary Colloidal Cu-Sn-Te Nanocrystals for Thermoelectric Thin Films.

Recent advances in copper chalcogenide-based nanocrystals (NCs), copper sulfide, and copper selenide derived nanostructures, have drawn considerable attention. However, reports of crystal phase and shape engineering of binary or ternary copper telluride NCs remain rare. Here, a colloidal hot-injection approach for producing binary copper/tin telluride, and ternary copper tin telluride NCs with controllable compositions, crystal structures, and morphologies is reported.

Microengineered Flexural Post Rings for Effective Blood Sample Fencing and High-Throughput Measurement of Clot Retraction Force.

During blood clotting, clot retraction alters its mechanical properties and critically affects hemostasis. Despite that, existing clot retraction assays hold limitations such as large footprint and low throughput. In this work, we report the design of flexural post rings for a miniaturized assay of clot retraction force (CRF) with high throughput.

High-temperature and multichannel quantum anomalous Hall effect in pristine and alkali-metal-doped CrBr monolayers.

The realization of the high-temperature and multichannel quantum anomalous Hall effect (QAHE) has been a central research area in the development of low-power-consumption electronics and quantum computing. Recently discovered two-dimensional (2D) ferromagnetic (FM) materials provide unprecedented opportunities for the exploration of the high-temperature QAHE. Based on first-principles approaches, we first reveal that a FM CrBr monolayer harbors topologically nontrivial conduction bands with a high Chern number of C = 2.

Solution Synthesis of Layered van der Waals (vdW) Ferromagnetic CrGeTe Nanosheets from a Non-vdW CrTeTemplate.

CrGeTe has recently emerged as a new class of two-dimensional (2D) materials due to its intrinsic long-range ferromagnetic order. However, almost all the reported synthesis methods for CrGeTe nanosheets are based on the conventional mechanical exfoliation from single-crystalline CrGeTe, which is prepared by the complicated self-flux technique. Here we report a solution-processed synthesis of CrGeTe nanosheets from a non-van der Waals (vdW) CrTe template.

Possible realization of the high-temperature and multichannel quantum anomalous Hall effect in graphene/CrBr heterostructures under pressure.

The recent studies of magno-assisted tunnelling in ferromagnetic van der Waals heterostructures formed by graphene and ultrathin CrBr films (D. Ghazaryan et al., Nat.