Angular Structure of Diffraction Processes

We discuss the general rules for the behavior of angular distributions in inelastic diffraction dissociation and differences in the angular structure of elastic and inelastic diffraction processes.     

软X射线激光全息术及其计算机模拟仿真

软Ｘ射线激光全息术采用短波长Ｘ射线激光光源，从而可获得空间分辨率很高的三维全息图，但目前它还存在许多问题。用计算机来模拟仿真提供了一种有力手段。本文采用方块、英文字母、汉字等作样品，对无透镜傅利叶变换软Ｘ射线激光全息术作了模拟仿真，其结果和可见光全息实验及理论都相符合。     

The effect of soft modes on solitons in a linear lattice

Solitons are simulated in an anharmonic linear lattice that is susceptible to a soft mode instability. The soft mode characteristic is introduced in the system by the addition of a term (−Au _n ² ) in the potential between the neighbouring atoms and the evolution of the system is studied as the soft mode parameterA varies from zero to the square of the limiting optical frequency. It is shown that the displacement pattern of the system shows three regions. First there is a region in which the relative displacements of the atoms show large amplitude oscillations. This is followed successively by a domain in which the relative displacements of the atoms are negligible and then by the soliton itself. In the soft mode region, the displacements of the atoms preceding the soliton decrease drastically in a linear fashion first, parabolically next and later become steady. It further exhibits a kind of devil’s stair cases.     

Bioinspired Self-healing Soft Electronics

Inspired by nature, various self-healing materials that can recover their physical properties after external damage have been developed. Recently, self-healing materials have been widely used in electronic devices for improving durability and protecting the devices from failure during operation. Moreover, self-healing materials can integrate many other intriguing properties of biological systems, such as stretchability, mechanical toughness, adhesion, and structural coloration, providing additional fascinating experiences. All of these inspirations have attracted extensive research on bioinspired self-healing soft electronics. This review presents a detailed discussion on bioinspired self-healing soft electronics. Firstly, two main healing mechanisms are introduced. Then, four categories of self-healing materials in soft electronics, including insulators, semiconductors, electronic conductors, and ionic conductors, are reviewed, and their functions, working principles, and applications are summarized. Finally, human-inspired self-healing materials and animal-inspired self-healing materials as well as their applications, such as organic field-effect transistors (OFETs), pressure sensors, strain sensors, chemical sensors, triboelectric nanogenerators (TENGs), and soft actuators, are introduced. This cutting-edge and promising field is believed to stimulate more excellent cross-discipline works in material science, flexible electronics, and novel sensors, accelerating the development of applications in human motion monitoring, environmental sensing, information transmission, etc.     

High Linearity,Low Hysteresis Ti3C2Tx MXene/AgNW/Liquid Metal Self-Healing Strain Sensor Modulated by Dynamic Disulfide and Hydrogen Bonds

Flexible wearable strain sensors have received extensive attention in human–computer interaction, soft robotics, and human health monitoring. Despite significant efforts in developing stretchable electronic materials and structures, developing flexible strain sensors with stable interfaces and low hysteresis remains a challenge. Herein, Ti₃C₂T_x MXene/AgNWs/liquid metal strain sensors (MAL strain sensor) with self-healing function are developed by exploiting the strong interactions between Ti₃C₂T_x MXene/AgNWs/LM and the disulfide and hydrogen bonds inside the self-healing poly(dimethylsiloxane) elastomers. AgNWs lap the Ti₃C₂T_x MXene sheets, and the LM acts as a bridge to increase the lap between Ti₃C₂T_x MXene and AgNWs, thereby improving the interface interaction between them and reducing hysteresis. The MAL strain sensor can simultaneously achieve high sensitivity (gauge factor for up to 3.22), high linearity (R² = 0.98157), a wide range of detection (e.g., 1%–300%), a fast response time (145 ms), excellent repeatability, and stability.In addition, the MAL strain sensor before and after self-healing is combined with a small fish and an electrothermally driven soft robot, respectively, allowing real-time monitoring of the swinging tail of the small fish and the crawling of the soft robot by resistance changes.     

Extended Antibonding States and Phonon Localization Induce Ultralow Thermal Conductivity in Low Dimensional Metal Halide

Thermal conductivity, which measures the ease at which heat passes through a crystalline solid, is controlled by the nature of the chemical bonding and periodicity in the solid. This necessitates an in-depth understanding of the crystal structure and chemical bonding to tailor materials with notable lattice thermal conductivity (κ_L). Herein, the nature of chemical bonding and its influence on the thermal transport properties (2–523 K) of all-inorganic halide perovskite Cs₃Bi₂I₉ are studied. The κ_L exhibits an ultralow value of ≈0.20  W m⁻¹K⁻¹ in 30–523 K temperature range. The antibonding states just below the Fermi level in the electronic structure arising from the interaction between bismuth 6s and iodine 5p orbitals, weakens the bond and causes soft elasticity in Cs₃Bi₂I₉. First-principles density functional theory (DFT) calculations reveal highly localized soft optical phonon modes originating from Cs-rattling and dynamic double octahedral distortion of 0D [Bi₂I₉]³⁻ in Cs₃Bi₂I₉. These low energy nearly flat optical phonons strongly interact with transverse acoustic modes creating an ultrashort phonon lifetime of ≈1 ps. While the presence of extended antibonding states gives rise to soft anharmonic lattice; Cs rattling provides sharp localized optical phonon modes, which altogether result in strong lattice anharmonicity and ultralow κ_L.     

Spiral-Shape Fast-Moving Soft Robots

Soft robots typically exhibit limited agility due to inherent properties of soft materials. The structural design of soft robots is one of the key elements to improve their mobility. Inspired by the Archimedean spiral geometry in nature, here, a fast-moving spiral-shaped soft robot made of a piezoelectric composite with an amorphous piezoelectric vinylidene fluoride film and a layer of copper tape is presented. The soft robot demonstrates a forward locomotion speed of 76 body length per second under the first-order resonance frequency and a backward locomotion speed of 11.26 body length per second at the third-order resonance frequency. Moreover, the multitasking capabilities of the soft robot in slope climbing, step jumping, load carrying, and steering are demonstrated. The soft robot can escape from a relatively confined space without external control and human intervention. An untethered robot with a battery and a flexible circuit (a payload of 1.665 g and a total weight of 1.815 g) can move at an absolute speed of 20 mm s⁻¹ (1 body length per second). This study opens a new generic design paradigm for next-generation fast-moving soft robots that are applicable for multifunctionality at small scales.     

Strain-Invariant,Highly Water Stable All-Organic Soft Conductors Based on Ultralight Multi-Layered Foam-Like Framework Structures

Soft and flexible conductors are essential for the development of soft robots, wearable electronics, electronic tissue, and implants. However, conventional soft conductors are inherently characterized by a large change in conductance upon mechanical deformation or under alternating environmental conditions, e.g., humidity, drastically limiting their application potential. This work demonstrates a novel concept for the development of strain-invariant, highly elastic and highly water stable all-organic soft conductors, overcoming the limitations of previous strain-invariant soft conductors. For the first time, thin film deposition technologies are combined in a three-dimensional fashion, resulting in micro- and nano-engineered, multi-layered (<50 nm), ultra-lightweight (< 15 mg cm⁻³) foam-like framework structures based on Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and Polytetrafluoroethylene (PTFE), characterized by a highly strain-invariant conductivity (≈184 S/m) between 80% compressive and 25% tensile strain. Both the initial electrical and mechanical properties are retained during long-term cycling, even after 2000 cycles at 50% compression. Furthermore, the PTFE thin film renders the framework structure highly hydrophobic, resulting in stable electrical properties, even when immersed in water for a month. Such innovative multi-scaled and multi-layered functional materials are of interest for a broad range of applications in soft electronics, energy storage and conversion, sensing, water and air purification, as well as biomedicine.     

SFGDO: Smart flower gradient descent optimization enabled generative adversarial network for recognition of Tamil handwritten character

The Tamil language is complicated to identify, and thus more efforts are devised in the literary works. The objective is to develop a model called the Smart Flower Gradient Descent optimization-based Generative Adversarial Network (SFGDO-based GAN) for recognising Tamil handwriting. The dataset is first used to acquire the input image. The undesired noises are then pre-processed using a bilateral filter, and the binarization procedure is carried out using gradient-based thresholding. The necessary characteristics are then extracted for further categorization of Tamil characters, including character length, character width, statistical features, Local Binary Pattern (LBP), Convolutional Neural Network (CNN), density features, and Histogram of Oriented Gradients (HOG) features. Finally, utilising the proposed SFGDO enabled GAN, Tamil handwritten characters are recognised. The proposed Smart Flower Gradient Descent optimization (SFGDO) algorithm is developed by integrating Smart Flower Optimization Algorithm SFOA) and Gradient Descent Optimization (GDO).     

A Versatile Ionomer-Based Soft Actuator with Multi-Stimulus Responses,Self-Sustainable Locomotion,and Photoelectric Conversion

The prospects of endowing artificial robotics or devices with increasingly complex and emergent life-like behaviors have attracted growing interest in the soft functional materials that mimic the versatile motions of living creatures in the iridescent nature. However, despite the flourishing achievements so far, soft actuators capable of sensitive multi-stimulus responses and self-sustainable movements, have been extensively pursued to reduce control complexity yet remains a challenging target. Here, through material-structural synergistic design incorporating stress-mismatching structure, high pseudo-negative coefficient of thermal expansion of perfluoro-sulfonic acid ionomer, comprehensive converting properties of carbon nanotube, and anisotropic large thermal expansion of PE polymer, an ionomer-based bilayer actuator is proposed, presenting high-performance actuation of various forms and nice stability, responsive to light (including sunlight without focusing, LED light), low voltage, mild heating, and humidity/solvent change. With a built-in structural feedback loop, the actuation performances are further explored to realize intelligent systems, including: 1) self-sustainable locomotion under sunlight irradiation with adjustable photophobic and phototropic direction as well as adaption to different topographies and loading conditions, 2) self-sustainable oscillation and solar-electric generating, and 3) bionic floristic reaction according to environmental change. These diversified actuation modes allow promising following-up designs for bio-hybrid soft robotics fueled by and harmonized with natural environments.