激光全息-散斑法分析腰椎内固定装置的稳定性

介绍了激光全息散斑法用于人体腰椎损伤后．内固定装置稳定性生物力学实验。分析了对椎间盘表面位移和变形的测量。对标本制备、加载装置、光路系统、实验方案设计及实验过程均进行了介绍。激光全息-散斑法具有精度高、全场、非接触测量的特点，实验结果表明，在模型模拟腰椎生理运动的大变形过程中，能够测得模型在不同运动位置时椎间盘表面发生的微小三维位移．并由位移求出椎间盘的变形．从而为不同内固定方式的稳定性对比分析提供依据。     

Wavelength-tunable and single-frequency semiconductor lasers forphotonic communications networks

The present status of wavelength-tunable and single-frequency devices needed for the broadband integrated services digital network (BISDN) of the future is reviewed. The various systems applications and requirements and, in turn, the device parameters that are relevant to those requirements are described. The basic material and structural parameters of the lasers are discussed, and the fundamental operational principles are explained. Various single-frequency, high-speed, and tunable laser structures are reviewed, and their characteristics are presented     

经皮激光椎间盘汽化减压术联合复方倍他米松对66例腰椎间盘突出症的疗效观察

目的:观察经皮激光椎间盘汽化减压术联合复方倍他米松椎间孔注射对腰椎间盘突出症的临床疗效。方法:将66例腰椎间盘突出症患者随机分成观察组和对照组,各33例。观察组给予经皮激光椎间盘汽化减压术联合复方倍他米松椎间孔注射,对照组给予复方倍他米松注射液骶管注射。两组均采取每周治疗1次。分别于治疗3次后、治疗3月后采用临床疾病诊断依据治疗好转标准及视觉模拟评分法(VAS)评分比较两组的临床疗效。结果:治疗3次后观察组有效率为96.97%;对照组有效率为72.72%,两组比较差异有统计学意义(P0.05);治疗3月后观察组有效率为93.94%;对照组有效率为69.70%,两组比较差异有统计学意义(P0.05)。结论:经皮激光椎间盘汽化减压术联合复方倍他米松椎间孔注射能加速腰腿疼痛症状的改善,可提高腰椎间盘突出症的临床疗效。     

红外线照射配合腰椎牵引联用康复护理对腰椎间盘突出症患者的疗效影响

目的:探讨红外线照射配合腰椎牵引并康复护理对腰椎间盘突出症的疗效影响。方法:选取2010年1月至2013年12月我科收治的腰椎间盘突出患者90例,随机分为观察组45例和对照组45例,其中对照组患者给予腰椎牵引治疗,观察组患者经腰椎牵引理疗后配合红外线照射并联合康复护理,观察两组患者疼痛症状好转情况。结果:观察组总有效率91.11%明显高于对照组77.78%,差异有统计学意义(P0.05)。结论:红外线照射配合腰椎牵引并康复护理能发挥协同作用,较单纯腰椎牵引疗法更为显著。     

Strain-Isolating Materials and Interfacial Physics for Soft Wearable Bioelectronics and Wireless,Motion Artifact-Controlled Health Monitoring

Recent developments of micro-sensors and flexible electronics allow for the manufacturing of health monitoring devices, including electrocardiogram (ECG) detection systems for inpatient monitoring and ambulatory health diagnosis, by mounting the device on the chest. Although some commercial devices in reported articles show examples of a portable recording of ECG, they lose valuable data due to significant motion artifacts. Here, a new class of strain-isolating materials, hybrid interfacial physics, and soft material packaging for a strain-isolated, wearable soft bioelectronic system (SIS) is reported. The fundamental mechanism of sensor-embedded strain isolation is defined through a combination of analytical and computational studies and validated by dynamic experiments. Comprehensive research of hard-soft material integration and isolation mechanics provides critical design features to minimize motion artifacts that can occur during both mild and excessive daily activities. A wireless, fully integrated SIS that incorporates a breathable, perforated membrane can measure real-time, continuous physiological data, including high-quality ECG, heart rate, respiratory rate, and activities. In vivo demonstration with multiple subjects and simultaneous comparison with commercial devices captures the SIS's outstanding performance, offering real-world, continuous monitoring of the critical physiological signals with no data loss over eight consecutive hours in daily life, even with exaggerated body movements.     

A Biomimetic Artificial Disc with Improved Mechanical Properties Compared to Biological Intervertebral Discs

Patients with serious spinal disc disorders will benefit from a novel artificial disc system that is suitable for clinical use in replacement arthroplasty. The disc is composed of a biomimetic three‐dimensional (3D) fabric with a triaxial fiber alignment that has superior mechanical properties when compared to conventional implants. This disc improves on the constitutional imperfections of biological intervertebral discs by eliminating the risk of rupture and delamination. The fabric bonds firmly to disc bodies, and functions in combination with bioactive bioresorbable pins and scaffolds as a stand‐alone system that maintains the position of the disc and promotes bone growth at the interface. The disc has high biocompatibility and can maintain biomimetic “J‐shaped” stress–strain behavior for up to sixty‐three million alternating stresses, which is the equivalent of natural biological movements for a period of more than 30 years. This technology exemplifies how, in the best biomaterials, biological flexibility may occasionally overcome artificial rigidity.     

Improvement on the dynamical performance of a power bipolar static induction transistor with a buried gate structure

The failure of a bipolar static induction transistor(BSIT) often occurs in the transient process between the conducting-state and the blocking-state,so a profound understanding of the physical mechanism of the switching process is of significance for designing and fabricating perfect devices.The dynamical characteristics of the transient process between conducting-state and blocking-state BSITs are represented in detail in this paper.The influences of material,structural and technological parameters on the dynamical performances of BSITs are discussed. The mechanism underlying the transient conversion process is analyzed in depth.The technological approaches are developed to improve the dynamical characteristics of BSITs.     

Thermomechanically Triggered Reversible Multi-Transformability of a Single Material System by Energy Swapping and Shape Memory Effects

Thermally triggered active metamaterials with shape memory polymers (SMPs) show greater potential for structural applications with reconfigurability than other programmable structures owing to their temporally stiff condition with shape locking. However, most SMP-based active metamaterials have not shown complex transformation, such as multi-modal and asymmetric deformations, because of the lack of an adaptable strategy with reasonable mechanics models. Moreover, conventional SMP has a critical drawback – irreversible transformability, limiting its reconfigurability for active metamaterials. Herein, a thermomechanical tool that allows a single material system to transform with reversible, multi-modal, and asymmetric deformations is constructed and demonstrated. Using transformation aids (TAs), a localized pre-stress and a temperature-dependent reverse stiffness effect to exchange energy with a lattice is conceived. The deformation of a single SMP system whose energy is swapped from TAs by localized pre-stress and reverse stiffness can transform into reversible, multi-modal, and asymmetric deformations with shape-locking. The methods can be used for reconfigurable structures, tuning symmetry, and chirality, especially for active acoustic metamaterials, deployable devices, and biomedical devices. The mechanics-inspired design approach of local deformation of TA and the interaction with the temperature-dependent stiffness drop of the lattice open an avenue to the robust design of thermally triggered active metamaterials.     

A Practical Traffic Scheduling Scheme for Differentiated Services of Healthcare Systems on Wireless Sensor Networks

Wireless sensor networks have recently been extensively researched due to the flexibility and cost savings they provide. One of the most promising applications of sensor networks is human health monitoring: wireless sensors are placed on the human body to form a wireless body network where the sensor node can continuously monitor real-time physiological parameters or human activities (motion detection). However, along with the flexibility, many problems arise due to a number of factors, including the bad quality of transmission media and the scarcity of resources. Moreover, sensor networks have different characteristics such as a variety of devices, different generated data, etc. From a quality of service (QoS) point of view, the healthcare domain can be seen as a real-time application demand to consider application requirements. Healthcare domains principally have stringent delay and loss requirements. Thus, considering different capabilities and ensuring time data delivery become necessary. Because wireless body area networks (WBAN) deal with human life, any delayed or lost data can endanger the user’s life. This paper proposes a differentiated traffic and scheduling scheme for WBAN. It is based on patients’ data classification and prioritization according to their current status and diseases. Through queue scheduling and path choice issues, the urgent data are delivered on time to provide a QoS guarantee for WBAN. Finally, it is shown that the proposed scheme is efficient for timely data transfer in WBAN.     

A two-dimensional simulation of organic transistors

In this paper, we analyze the operation of organic thin-film transistors (TFT's) using two-dimensional (2-B) numerical simulation to: (1) validate the use of simple MOSFET theory to describe the above-threshold behavior; (2) clarify the subthreshold characteristics, and short-channel effects; and (3) illustrate the operation of organic bilayer devices. Our analysis clarifies a number of issues that can help in device design. We also point out differences between the material parameters used in Si-MOSFET and organic FET simulation, and discuss the circumstances under which a semiconductor device simulator can be used for the simulation of organic transistors     

Active Reconfigurable Tristable Square‐Twist Origami

Origami structures offer valuable applications in many fields, ranging from metamaterials to robotics. The multistable characteristics of origami structures have been pursued for acquiring unique reconfigurable features. For achieving this goal, an unusual polymeric tristable origami structure is demonstrated using a classic square‐twist origami configuration. By manipulating both material properties and geometric parameters of the heteropolymer structures, a design principle for tailoring the multistable configuration in the square‐twist origami is established based on variation of the structural potential energy. Under thermal triggering, the stiffness of the deformable structure is dramatically reduced, which causes an increase in the structural degree of freedom, allowing for self‐deployment via release of the prestored energy in the elastic twisted hinges. Utilizing such unique features and design principles, a prototype of frequency reconfigurable origami antenna of five diverse operating modes and a programmable multiple‐input multiple‐output communication system is subsequently designed and assembled, aiming to substantially promote the channel capacity and communication reliability. The findings and results firmly provide a remarkable design principle and strategy for advancing active origami structures and devices in shape‐morphing systems.     

A Modeling Framework for Jamming Structures

Jamming is a structural phenomenon that provides tunable mechanical behavior. A jamming structure typically consists of a collection of elements with low effective stiffness and damping. When a pressure gradient, such as vacuum, is applied, kinematic and frictional coupling increase, resulting in dramatically altered mechanical properties. Engineers have used jamming to build devices from tunable-stiffness grippers to tunable-damping landing gear. This study presents a rigorous framework that systematically guides the design of jamming structures for target applications. The force-deflection behavior of major types of jamming structures (i.e., grain, fiber, and layer) in fundamental loading conditions (e.g., tension, shear, and bending) is compared. High-performing pairs (e.g., grains in compression, layers in shear, and bending) are identified. Parameters that go into designing, fabricating, and actuating a jamming structure (e.g., scale, material, geometry, and actuator) are described, along with their effects on functional metrics. Two key methods to expand on the design space of jamming structures are introduced: using structural design to achieve effective tunable-impedance behavior in specific loading directions, and creating hybrid jamming structures to utilize the advantages of different types of jamming. Collectively, this study elaborates and extends the jamming design space, providing a conceptual modeling framework for jamming-based structures.     

Comparison of drain structures in n-channel MOSFET's

Practical limitations in channel lengths for n-channel MOSFET'S under 5-V operation are discussed for conventional arsenic-drain, phosphorus-drain, phosphorus-arsenic double diffused drain (DDD), and lightly doped drain (LDD) structures. Process parameter dependence of device characteristics and optimal process conditions are also evaluated for each drain structure. It is clarified that the minimum usable channel length is about 0.7-µm, which is realized by the DDD and LDD devices. In these devices, the hot-carrier-induced device degradation is no longer a major restriction on minimum channel length, but the short-channel effect and the parasitic bipolar breakdown are dominant restrictions. The phosphorus drain with a shallow junction formed by rapid thermal annealing can expand the arsenic drain limitation.     

Highly Stretchable and Strain-Insensitive Liquid Metal based Elastic Kirigami Electrodes (LM-eKE) (Adv. Funct. Mater. 30/2023)

Kirigami, a traditional paper-cutting art, is a promising method for creating mechanically robust circuitry for unconventional devices capable of extreme stretchability through structural deformation. In this study, this design approach is expanded upon by introducing Liquid Metal based Elastic Kirigami Electrodes (LM-eKE) in which kirigami-patterned soft elastomers are coated with eutectic gallium-indium (EGaIn) alloy. Overcoming the mechanical and electrical limitations of previous efforts with paper-like kirigami, the all soft LM-eKE can be stretched to 820% strain while the electrical resistance only increases by 33%. This is enabled by the fluidic properties of the EGaIn coating, which maintains high electrical conductivity even as the elastic substrate undergoes extreme deformation. Applying the LM-eKE to human knee joints and fingers, the resistance change during physical activities is under 1.7%, thereby allowing for stable electrical operation of wearable health monitoring devices for tracking electroencephalogram (EEG) signals and other physiological activity.     

腰椎间盘突出症患者下肢体表红外热象区域分布

本研究针对腰椎间盘突出症患者临床症状客观评价缺少指标的情况，总结６８例腰椎间盘突出症患者的下肢体表红外热象情况，提出和进一步明确：（１）体表红外热图对神经根受损节段的定位诊断意义并不肯定；（２）体表红外热图可心同时反映神经要及腰椎结构力学紊乱的状况；（３）健患侧温差程序及患侧冷区分布大小与神经根刺激体征严重程度成正比。     

Experimental study and modeling of band-to-band tunneling leakage current in thin-oxide MOSFETs

The band-to-band tunneling current in MOS transistors is studied by measuring and simulating the leakage characteristics of devices with an oxide thickness in the range 100–250 Å and different source-drain junctions. In case of conventional As implanted junctions a simple physically based expression for the tunneling leakage current as a function of applied voltage and oxide thickness with empirically matched parameters is derived. A 2-D process and device simulation approach has been used for analysis and reduction of the band-to-band tunneling leakage in conventional DDD and GGO transistors.     

A large-signal SOI MOSFET model including dynamic self-heatingbased on small-signal model parameters

A new technique for a large-signal SOI MOSFET model with self-heating is proposed, based on thermal and electrical parameters extracted by fitting a small-signal model to measured s-parameters. A thermal derivative approach is developed to calculate the thermal resistance when the isothermal dc drain conductance is extracted from small-signal fitting. The thermal resistance is used to convert the measured dc current-voltage (I-V) characteristics containing the self-heating effects to the isothermal I-V characteristics needed for the large-signal model. Large-signal pulse and sinusoidal input signals are used to verify the model by measurement, and shown to reproduce the observed large-signal behavior of the devices with great accuracy, especially when two or more thermal time constants are used     

Finite-element analysis for lumbar interbody fusion under axial loading

A parametric study was conducted to evaluate axial stiffness of the interbody fusion, compressive stress, and bulging in the endplate due to changes in the spacer position with/without fusion bone using an anatomically accurate and validated L2-L3 finite-element model exercised under physiological axial compression. The results show that the spacer plays an important role in initial stability for fusion, and high compressive force is predicted at the ventral endplate for the models with the spacer and fusion bone together. By varying the positioning of the spacer anteriorly along anteroposterior axis, no significant change in terms of axial stiffness, compressive stress, and bulging of the endplate are predicted for the implant model. The findings suggest that varying the spacer position in surgical situations does not affect the mechanical behavior of the lumbar spine after interbody fusion.     

Effect of the Electrode Material on the Electrical-Switching Characteristics of Nonvolatile Memory Devices Based on Poly($o$-anthranilic acid) Thin Films

We investigated the effect of the electrode material on the electrical-switching characteristics (i.e., electrical-switching behavior, switching voltage, and on/off current ratio) of a nonvolatile resistive-memory device based on an active poly($o$-anthranilic acid) thin film. The switching characteristics of the active polymer layer were found to depend strongly on the bottom-electrode (BE) material. Depending on which material was used, the devices exhibited two different switching behaviors, namely, a polarity-dependent and a polarity-independent one. The polarity-independent switching behavior was particularly observed in devices fabricated with an aluminum BE, which can be attributed to the formation of a native oxide layer on this substrate.      

有机材料在光限制中的应用

对光限制器件的特性进行了简单的评述,并对由自散焦过程产生光限制的机理进行了分析.采用z-扫描方法对有机材料分散红一的非线性折射过程和光限制特性进行了实验研究.对其结果进行了分析讨论,这种分析对于以自作用效应产生最佳光限制效应是十分有用的.