数字金融对商业银行信用风险的影响研究

数字金融的快速发展,给传统金融机构带来了深刻的变革,传统商业银行的各项业务都受到了数字金融的冲击,分析数字金融发展对商业银行信用风险的影响有其现实意义。本文以38家上市商业银行为样本,研究区间为2011-2020年,采用双向固定效应模型进行实证分析,并进一步进行了稳健性检验和异质性分析。研究结果发现,数字金融的发展增加了商业银行的信用风险。此外,数字金融发展对不同商业银行信用风险影响存在差异,城市商业银行受到数字金融冲击最为显著。

Modular Soft Robotic Crawlers Based on Fluidic Prestressed Composite Actuators

Soft robotic crawlers have limited payload capacity and crawling speed.This study proposes a high-performance inchworm-like modular robotic crawler based on fluidic prestressed composite(FPC)actuators.The FPC actuator is precurved and a pneumatic source is used to flatten it,requiring no energy cost to maintain the equilibrium curved shape.Pressurizing and depressurizing the actuators generate alternating stretching and bending motions of the actuators,achieving the crawling motion of the robotic crawler.Multi-modal locomotion(crawling,turning,and pipe climbing)is achieved by modular reconfiguration and gait design.An analytical kinematic model is proposed to characterize the quasi-static curvature and step size of a single-module crawler.Multiple configurations of robotic crawlers are fabricated to demonstrate the crawling ability of the proposed design.A set of systematic experiments are set up and conducted to understand how crawler responses vary as a function of FPC prestrains,input pressures,and actuation frequencies.As per the experiments,the maximum carrying load ratio(carrying load divided by robot weight)is found to be 22.32,and the highest crawling velocity is 3.02 body length(BL)per second(392 mm/s).Multi-modal capabilities are demonstrated by reconfiguring three soft crawlers,including a matrix crawler robot crawling in amphibious environments,and an inching crawler turning at an angular velocity of 2/s,as well as earthworm-like crawling robots climbing a 20 inclination slope and pipe.

Stretchable and durable HD-sEMG electrodes for accurate recognition of swallowing activities on complex epidermal surfaces

Surface electromyography(sEMG)is widely used in monitoring human health.Nonetheless,it is challenging to capture high-fidelity sEMG recordings in regions with intricate curved surfaces such as the larynx,because regular sEMG electrodes have stiff structures.In this study,we developed a stretchable,high-density sEMG electrode array via layerby-layer printing and lamination.The electrode offered a series of excellent human‒machine interface features,including conformal adhesion to the skin,high electron-to-ion conductivity(and thus lower contact impedance),prolonged environmental adaptability to resist water evaporation,and epidermal biocompatibility.This made the electrode more appropriate than commercial electrodes for long-term wearable,high-fidelity sEMG recording devices at complicated skin interfaces.Systematic in vivo studies were used to investigate its ability to classify swallowing activities,which was accomplished with high accuracy by decoding the sEMG signals from the chin via integration with an ear-mounted wearable system and machine learning algorithms.The results demonstrated the clinical feasibility of the system for noninvasive and comfortable recognition of swallowing motions for comfortable dysphagia rehabilitation.

Fine-Grained Bulk NiTi Shape Memory Alloy Fabricated by Rapid Solidifcation Process and Its Mechanical Properties and Damping Performance

A near-equiatomic NiTi shape memory alloy was fabricated by rapid solidification process through vacuum arc melting followed by vacuum suction casting in water-cooled thick copper mold. The rapidly solidified （or suction cast） NiTi alloy shows much finer grains and homogenous microstructure, in particular a uniform distribution of various fine precipitates, compared to the conventional cast one. The resultant alloy also exhibits the homogenous Ni distribution in the matrix of the alloy, allowing the martensitic transformation to take place throughout the NiTi alloy matrix simultaneously and resulting in sharper transformation peaks compared to the conventional cast alloy. Moreover, the suction cast NiTJ alloy shows a significant improvement over the conventional cast one, in terms of possessing higher deformation recovery rates and displaying the increased compressive strength and damping capacity by 4% and 20%, respectively.

6061铝颗粒层增强7075铝基复合材料的微观结构及阻尼性能

采用热轧法制备出具有颗粒层状结构的6061p/7075铝基复合材料以改善7075铝合金的阻尼性能。通过OM、SEM、EDS和XRD分析6061p/7075层状铝基复合材料的微观组织,分别采用万能力学试验机和动态热机械分析仪分析其力学性能和阻尼行为。研究表明,6061铝颗粒层存在大量的颗粒间界面和微小孔隙,6061铝颗粒层与7075铝基体之间界面结合良好,没有发生界面反应;6061p/7075层状铝基复合材料最大抗拉强度为370.5 MPa,比7075铝基体提高了30%;6061p/7075层状铝基复合材料和基体材料的内耗值分别随着温度和应变量的升高而增大,复合材料的阻尼性能明显优于7075铝基体,在360℃时,复合材料的内耗值高达0.117,比7075铝基体提高了149%;6061p/7075层状铝基复合材料和基体材料的储能模量分别随着温度和应变量的升高而降低,在30℃时,复合材料的储能模量为38601 MPa,比7075铝基体高16%。

A mass-customizable dermal patch with discrete colorimetric indicators for personalized sweat rate quantification

In this paper,we present a disposable,colorimetric,user-friendly and mass-customizable dermal patch for chronological collection and discrete real-time in situ measurement of sweat secretion over a small area of skin.The patch consists of a laminated filter paper patterned into radially arranged channels/fingers with water-activated dyes at their tips.As channels are filled during perspiration,their tips change color once fully saturated,providing easily identifiable levels of water loss which in turn can be mapped to personal dehydration levels.The patch can be manufactured at low cost in a variety of sizes to allow hydration monitoring for individuals participating in activities under different conditions(intensity,temperature,humidity,etc.).Furthermore,we describe an analytical model that enables mass customization of such a flexible wearable system accommodating a broad range of sweat rates and volumes to generate patch designs that are personalized to an individual’s sweat rate,desired time of usage,and the temporal resolution of the required feedback.As a proof-of-concept demonstration,we characterized laser-fabricated patches that cover(7 cm×5 cm)area of skin having various wicking materials,thicknesses(180–540μm),and pore sizes(3–11μm).Tests were conducted at various flow rates simulating different sweating intensities in the range of 1.5–15 mg/cm^(2)/min.Experimental results for the case of a half-marathon runner targeting 90 min of usage and sweating at a rate of 1.5 mg/cm2/min indicated measurement accuracy of 98.3%when the patch is completely filled.

Integrated sensing and delivery of oxygen for next- generation smart wound dressings

Chronic wounds affect over 6.5 million Americans and are notoriously difficult to treat.Suboptimal oxygenation of the wound bed is one of the most critical and treatable wound management factors,but existing oxygenation systems do not enable concurrent measurement and delivery of oxygen in a convenient wearable platform.Thus,we developed a low-cost alternative for continuous O 2 delivery and sensing comprising of an inexpensive,paper-based,biocompatible,flexible platform for locally generating and measuring oxygen in a wound region.The platform takes advantage of recent developments in the fabrication of flexible microsystems including the incorporation of paper as a substrate and the use of a scalable manufacturing technology,inkjet printing.Here,we demonstrate the functionality of the oxygenation patch,capable of increasing oxygen concentration in a gel substrate by 13%(5ppm)in 1h.The platform is able to sense oxygen in a range of 5–26 ppm.In vivo studies demonstrate the biocompatibility of the patch and its ability to double or triple the oxygen level in the wound bed to clinically relevant levels.

Deep brain stimulation for the treatment of cerebral palsy: A review

Deep brain stimulation(DBS)has been used as a safe and effective neuromodulation technique for treatment of various diseases.A large number of patients suffering from movement disorders such as dyskinesia may benefit from DBS.Cerebral palsy(CP)is a group of permanent disorders mainly involving motor impairment,and medical interventions are usually unsatisfactory or temporarily active,especially for dyskinetic CP.DBS may be another approach to the treatment of CP.In this review we discuss the targets for DBS and the mechanisms of action for the treatment of CP,and focus on presurgical assessment,efficacy for dystonia and other symptoms,safety,and risks.