Programmable Devices Research Articles

Leaf-inspired multiresponsive MXene-based actuator for programmable smart devices.

Natural leaves, with elaborate architectures and functional components, harvest and convert solar energy into chemical fuels that can be converted into energy based on photosynthesis. The energy produced leads to work done that inspired many autonomous systems such as light-triggered motion. On the basis of this nature-inspired phenomenon, we report an unprecedented bilayer-structured actuator based on MXene (Ti3C2T x )-cellulose composites (MXCC) and polycarbonate membrane, which mimic not only the sophisticated leaf structure but also the energy-harvesting and conversion capabilities. The bilayer actuator features multiresponsiveness, low-power actuation, fast actuation speed, large-shape deformation, programmable adaptability, robust stability, and low-cost facile fabrication, which are highly desirable for modern soft actuator systems. We believe that these adaptive soft systems are attractive in a wide range of revolutionary technologies such as soft robots, smart switch, information encryption, infrared dynamic display, camouflage, and temperature regulation, as well as human-machine interface such as haptics.

Effects of electron donating and accepting moieties on electrical memory behaviors of polymers

In this study, three different series of vinyl copolymers bearing electron donating and accepting moieties in various compositions and their homopolymers were synthesized by reversible addition-fragmentation chain transfer polymerizations. They all were soluble in conventional organic solvents and gave good quality nanoscale films via conventional coating and drying processes. They were thermally stable up to 242 °C or higher temperatures. Their optical and electrochemical properties as well as electron densities and mass densities were measured. The nanoscale film morphologies were further examined by synchrotron grazing incidence X-ray scattering analysis; they were confirmed as amorphous or structurally-featureless films. All polymers exhibited various electrical properties depending on the polymers and film thicknesses. In particular, only p-type digital memory characteristics were observed within certain film thickness windows, regardless of electron-donating polymers, electron-accepting polymers, and their copolymers. Moreover, all polymers revealed high memory performances with low switching-ON voltages, high ON/OFF current ratios and high reliabilities even in air ambient conditions. The memory behaviors followed a combination of hopping conduction and trap-limited space charge limited conduction in the OFF-state and hopping conduction in the ON-state. However, the film thickness window showing digital memory characteristics was significantly dependent upon the compositions of electron donating and accepting moieties. Higher fraction of electron-donating moieties provided wider film thickness window for digital memory. For this aspect, the electron-accepting polymers could gain great benefits by incorporating electron-donating moieties, whereas the electron-donating polymers could attain only negative impacts via the addition of electron-accepting moieties. Overall, all polymers of this study are suitable for the low-cost mass production of high-performance programmable memory devices.

Development of Remote Instrumentation and Control for Laboratory Experiments using Handheld Devices

The unprecedented growth in Internet technologies has created revolutionary changes in the use of collaborative learning tools with remote experimentation. These tools enhance the experiential learning aspects of engineering education. Laboratory experiments are integral part of science and engineering education. Automation is changing the nature of these laboratories, and the focus of the system designer is on the availability of various interfacing tools to access the laboratory hardware remotely with the integration of computer supported learning environment.Work on laboratory experiments and project works requires access to expensive hardware equipments. The high cost of these instruments along with time consuming development process of experimentation in the educational process creates a significant bottleneck. There is a need for the development of remote laboratory using which the users can access the laboratory instruments and the programmable devices remotely on their smart phones/tablets to perform the laboratory experiments. This implementation avails laboratory facility for complete twenty four hours a day and will increase the productivity of the laboratory hardware and measuring instruments.This paper presents the detailed architecture and the implementation details of remote laboratory by which user can perform laboratory experiments remotely. Develop mobile based remote laboratory where user can access remote laboratory on his smart phone or tablet to perform the experiments. Software application is developed on Android platform for the implementation.

Photothermal and Moisture Actuator Made with Graphene Oxide and Sodium Alginate for Remotely Controllable and Programmable Intelligent Devices.

Functional materials with energy storage and conversion properties have been useful for actuating devices. Here, a new kind of torsional fiber-based actuator including graphene oxide (GO) and natural sodium alginate was prepared by traditional wet spinning and twisting methods, during which the fiber structure was reconstructed, and the mechanical energy was prestored. When the twisted GO/SA (graphene oxide/sodium alginate) fiber was stimulated by infrared light or moisture, the torsional structure of the fiber was activated instantaneously to generate rapid and reversible rotational motion, thus realizing the automatic release and re-storage process of rotational kinetic energy. In addition, the full revolutions of the twisted GO/SA fiber have no attenuation after 100 reversible rotations when stimulated by moisture, which proves the excellent rotational stability. Due to its excellent flexibility and wettability, the twisted GO/SA fiber can be woven into a network or prepared into a series of programmable intelligent devices, which is of great significance for future flexible intelligent electronic devices.

Strain regulation of two-dimensional transition metal dichalcogenides

As layered materials beyond graphene discovered after 2004, two-dimensional (2D) transition metal dichalcogenides (TMDs) are vital to fundamental research and practical applications, owing to their unique crystal structures and excellent properties, as well as diversity of the electronic band structures. 2D TMDs have played an important role in electronics, optoelectronics, energy storage and catalysis. To meet with the increasing requirements of programmable and function-integrated devices, property modulation could be concerned as one of the most essential strategies for 2D TMDs. In comparison with conventional external electrical field induction, strain regulation could be much more efficient. In detail, external induction through the electrical field leads to the electron delocalization along the field direction and then induces the transformation of band structures, but electrical field exhibits small modulation for monolayer TMDs. On the contrary, the strain regulation shows excellent tuning efficiency for continuous and reversible modulation. As a result, the strain regulation has become a commonly-used strategy for property tuning of 2D TMDs. On the basis of the lattice transformation, the strain regulation of 2D TMDs can lead to different overlapping of d and p orbits of metal and chalcogen atoms, and then affect the electronic structures of 2D TMDs. Therefore, it can be applied to electronics, optoelectronics, magnetic devices and piezoelectronics. The strategies of introducing strains to 2D TMDs are classified into lattice induction, local deformation, macroscopic regulation and so on. Lattice induction is attributable to the structural distortions and mismatches, including atomic defect induction and lattice mismatch induction. The former one demonstrates that the microenvironment affected by atomic vacancies and doping atoms can introduce strain to 2D TMDs. The latter one means that the lattice mismatches between two materials (between two different TMDs in a heterostructure or between a TMD and the substrate) can result in lattice distortion and then induce the strain. However, strain introduced through lattice induction is fixed and difficult to achieve the reversible modulation. Local deformation refers to the morphological transformation at the scale of several micrometers, which can be induced by the bubbles and wrinkles of 2D TMDs, external forces of tips, as well as patterned substrates. Generally, large but nonuniform strain can be introduced to 2D TMDs through the local deformation, which results in the funnel effects and then induces large property variation. Furthermore, macroscopic regulation introduces the strains to the lattices, including the deformation of flexible substrates (bend, tension and compression), external pressure (applied by the diamond anvil cell) and thermal expansion coefficient mismatch. Macroscopic regulation would be compatible with industrial manufacture to achieve strain regulation on an extremely large scale in the future. There are some other ways to achieve strain regulation such as the design of special stack structures and the induction of the external electrical field. After summarizing the methods of introducing strain to 2D TMDs, we presented the applications based on strain regulation, such as field effect transistors, flexible photodetectors and strain sensors. Finally, we pointed out the further development and challenges of strain regulation of 2D TMDs.

Specific ion effects directed noble metal aerogels: Versatile manipulation for electrocatalysis and beyond.

Noble metal foams (NMFs) are a new class of functional materials featuring properties of both noble metals and monolithic porous materials, providing impressive prospects in diverse fields. Among reported synthetic methods, the sol-gel approach manifests overwhelming advantages for versatile synthesis of nanostructured NMFs (i.e., noble metal aerogels) under mild conditions. However, limited gelation methods and elusive formation mechanisms retard structure/composition manipulation, hampering on-demand design for practical applications. Here, highly tunable NMFs are fabricated by activating specific ion effects, enabling various single/alloy aerogels with adjustable composition (Au, Ag, Pd, and Pt), ligament sizes (3.1 to 142.0 nm), and special morphologies. Their superior performance in programmable self-propulsion devices and electrocatalytic alcohol oxidation is also demonstrated. This study provides a conceptually new approach to fabricate and manipulate NMFs and an overall framework for understanding the gelation mechanism, paving the way for on-target design of NMFs and investigating structure-performance relationships for versatile applications.

Effects of Ti Electrode on the Electrical Properties of Filament within Al2O3 Based Antifuse

Metal-insulator-metal antifuse is a kind of one-time programmable device that exhibits a great difference in impedance before and after programming, and it is widely used in the area of nonvolatile memories or programmable array logic devices for radiation-hardened space environment, such as PROM (programmable read-only memory), and FPGA (field programmable gate arrays). In this work, we fabricated a novel antifuse device with an ALD Al2O3 dielectric layer sandwiched between a Tungsten (W) bottom electrode and a top Ti electrode. The MIM stack exhibits a via-hole structure. An Al2O3 film was deposited by atomic layer deposition (ALD), The bottom metal (W) was deposited by chemical vapor deposition (CVD), and a 4000 Å oxide layer was subsequently deposited by plasma enhanced chemical vapor deposition (PECVD). Then, a 0.5 µm via was etched through the oxide, which defined the antifuse area. Afterwards, Al2O3 film was deposited, followed by physical vapor deposition (PVD) of Ti film as the top metal electrode. The Al2O3 dielectric was 7-nm thick, and the device area was 0.5 µm by 0.5 µm. In this paper, we investigated the filament properties after the antifuse is broken down. Extremly low on-state resistance is achieved by taking advantage of current overshoot in our original structure. After the antifuse breaks down, its resistance decreases to approximately 20 Ω. The filament properties are found to be independent on the breakdown polarities, as shown in Fig.1. While the filament properties show strong polarity dependency. If a positive voltage sweep from 0 to 1 V is applied to the top Ti electrode, the resistance would further decrease; if the sweep voltage is negative, the resistance would increase. We have studied the temperature dependency of I-V curves of initial formed filament and find the current decreases with temperature increase, exhibiting a metallic nature. The further decreased resistance filament shows the same temperature dependency, whereas the increased resistance filament after negative sweep voltage shows positive temperature coefficient, indicating a semiconducting characteristic. The negative voltage causes a filament transition from metallic-like nature to semiconducting-like characteristic which is found to be dominated by the oxygen vacancies density at the Ti/Al2O3 interface. A mechanism of the filament formation and transition is proposed that the filament is composed of a metal part (a mixture of metal and insulator reactions) and oxygen vacancy part. The properties of the filament formed in the Al2O3 based antifuse were demonstrated by studying the temperature dependence of the current-voltage characteristics. Fig. 2(a) shows the temperature dependence of I-V curves of the initial formed filament ranges from 25℃ to 125℃. The current reduces with the increasing temperature, indicating a metallic nature of the filament. The log(I)-log(V) curve in the inset of Fig. 2(a) is a straight line with a slope nearly equals to 1, also demonstrating the Ohmic characteristics. The temperature dependence of I-V curves of the filament after negative sweep is also analyzed, as is shown in Fig. 2(b). For the complete temperature range, the current can be fitted using equation , where Reff is the effective resistance of the filament, and the exponent α is close to unity indicating that the conduction is nearly Ohmic. It can be observed that the current increases with the increasing temperature, and the Reff drops from 348 Ω to 326 Ω with the temperature going up from 25℃ to 125℃. Which demonstrates that the reset filament exhibiting semiconducting-like behavior. The process of the filament formation and the filament resistance transition is illustrated in Fig. 3(a-e). (a) Pristine state. (b) The formation of initial oxygen vacancy filament. (c) The initial formed filament causes an abrupt increase of leakage current, leading to the electrochemical reaction driven by large Joule heating and formed mixture metal filament near the bottom W electrode. (d) When a positive voltage is applied to Ti electrode, it would further enhance electrochemical reactions and result in further growth of the filament. (e) When a negative voltage is applied to Ti electrode, some oxygen ions move back to the filament and recombine with oxygen vacancies resulting in rupture of vacancy part filament. The detailed filament transition mechanism would be displayed in the full paper. Figure 1

Digital instrument with configurable hardware and firmware for multi-channel time measures

A new digital instrument for timing of events is presented. It is based on a reconfigurable, high-performance, 16-channel time-to-digital converter implemented in a Xilinx 7 Series 28-nm field programmable gate array device. Each channel provides timestamps with a least significant bit of 2 ps that states the resolution, whereas instead the single-shot precision is below 12.5 ps rms with the possibility of multihit measures at the maximum rate of 20 MHz. The default width of the full-scale range is 157 µs that can be extended at users choosing up to 15 days by means of proper time tagging procedures made available. The instrument achieves performance in terms of precision, resolution, and full-scale range of measurement at the state-of-art of existing solutions. The novelty is that besides performance, the presented instrument is totally reconfigurable by the user both in the hardware and in the firmware parts. Moreover, novel techniques of event acquisition (e.g., level-zero trigger) are introduced. These further features are not present in any other instrument available nor in the literature or in commerce and constitute a difference with respect to all referenced instruments.

Joint Switch Upgrade and Controller Deployment in Hybrid Software-Defined Networks

To improve traffic management ability, Internet Service Providers (ISPs) are gradually upgrading legacy network devices to programmable devices that support Software-Defined Networking (SDN). The coexistence of legacy and SDN devices gives rise to a hybrid SDN. Existing hybrid SDNs do not consider the potential performance issues introduced by a centralized SDN controller: flow requests processed by a highly loaded controller may experience long tail processing delay; inappropriate multi-controller deployment could increase the propagation delay of flow requests. In this paper, we propose to jointly consider the deployment of SDN switches and their controllers for hybrid SDNs. We formulate the joint problem as an optimization problem that maximizes the number of flows that can be controlled and managed by the SDN and minimizes the propagation delay of flow requests between SDN controllers and switches under a given upgrade budget constraint. We show this problem is NP-hard. To efficiently solve the problem, we propose some techniques (e.g., strengthening the constraints and adding additional valid inequalities) to accelerate the global optimization solver for solving the problem for small networks and an efficient heuristic algorithm for solving it for large networks. The simulation results from real network topologies illustrate the effectiveness of the proposed techniques and show that our proposed heuristic algorithm uses a small number of controllers to manage a high amount of flows with good performance.

Design and Implementation of Autonomous and Non-Autonomous Time-Delay Chaotic System Based on Field Programmable Analog Array.

Time-delay chaotic systems can have hyperchaotic attractors with large numbers of positive Lyapunov exponents, and can generate highly stochastic and unpredictable time series with simple structures, which is very suitable as a secured chaotic source in chaotic secure communications. But time-delay chaotic systems are generally designed and implemented by using analog circuit design techniques. Analog implementations require a variety of electronic components and can be difficult and time consuming. At this stage, we can now solve this question by using FPAA (Field-Programmable Analog Array). FPAA is a programmable device for implementing multiple analog functions via dynamic reconfiguration. In this paper, we will introduce two FPAA-based design examples: An autonomous Ikeda system and a non-autonomous Duffing system, to show how a FPAA device is used to design programmable analog time-delay chaotic systems and analyze Shannon entropy and Lyapunov exponents of time series output by circuit and simulation systems.

Modified X–Y routing for mesh topology based NoC router on field programmable gate array

Network on chip (NoC) has been proposed as an enormously scalable solution to address communication problems in system on chip (SoC). The interconnections among multiple cores/multiple Intellectual Property modules on a chip have a major impact on communication and performance of the chip design in terms of area, throughput, latency and power. Hence, an efficient design of the NoC interconnect is of paramount importance. In this study, a novel idea of the NoC router using a single-side buffer in the input block and a programmable priority encoder in the scheduler is discussed and a 4 × 4 mesh topology based router design is implemented on a field programmable gate array device using these blocks. This gives an area optimisation of the router due to the use of a small buffer. Furthermore, a modified X–Y routing algorithm is discussed and implemented for the 8 × 8 mesh topology-based router. The result shows that the modified X–Y routing algorithm requires only two hops to reach any source destination pair resulting in latency optimisation of the NoC router. Thus, the router design with a single buffer and a modified X–Y routing algorithm provides the best solution for area and latency optimisation.

ИМПУЛЬСНЫЙ СТАБИЛИЗАТОР НАПРЯЖЕНИЯ С ЦИФРОВЫМ УПРАВЛЕНИЕМ ДЛЯ АВТОНОМНОЙ СИСТЕМЫ ЭЛЕКТРОПИТАНИЯ

Актуальность. Результативность геофизических, геологоразведочных, метеорологических работ и работ по мониторингу окружающей среды во многом определяется системами электропитания испытательной и исследовательской аппаратуры. Специфика таких работ зачастую подразумевает использование полевых автономных систем. Первичными источниками энергии в таких системах, как правило, являются возобновляемые источники энергии, например солнечные батареи, ветро- или гидроэлектроустановки, а вторичными источниками энергии – аккумуляторные батареи. Источники энергии объединяются в систему электропитания посредством импульсных преобразователей энергии, которые выполняют функции по передаче энергии от её источников к потребителям, стабилизации напряжения на выходных шинах, предназначенных для питания потребителей и по повышению энергетической эффективности первичных источников энергии за счёт обеспечения их работы в режиме генерации максимальной мощности. Потребителем электроэнергии таких систем электропитания является сложная и разнородная аппаратура, часто имеющая импульсный характер энергопотребления, что приводит к значительным отклонениям напряжения на выходных шинах системы электропитания от стабильного уровня и, как следствие, к взаимному влиянию отдельных потребителей, приводящему к сбоям в их работе. Таким образом, импульсные преобразователи энергии должны обладать как способностью обеспечения работы первичных источников энергии в режиме генерации максимальной мощности, так и способностью обеспечивать режим стабилизации напряжения на выходных шинах. В режиме генерации максимальной мощности устройство управления импульсным преобразователем обеспечивает перевод и удержание рабочей точки на мощностной характеристике первичного источника в окрестности максимума мощности. В таком устройстве управления реализуется достаточно сложный алгоритм экстремального регулирования и на современном уровне развития техники устройство управления выполняется на основе программируемого цифрового устройства. Решение вопросов по применению этого же программируемого цифрового устройства и для цели управления импульсным преобразователем в режиме стабилизации напряжения на выходных шинах является актуальной задачей, поскольку позволит уменьшить количество элементов в устройстве управления преобразователем, что снизит его собственное энергопотребление и повысит надёжность функционирования. Цель работы: решение теоретических и практических задач по обеспечению цифрового управления импульсным преобразователем в режиме стабилизации выходного напряжения с обеспечением малой длительности переходных процессов, вызванных приращениями тока нагрузки и астатизма выходного напряжения. Методы: теория импульсных систем автоматического управления, математическое моделирование процессов в импульсных стабилизаторах напряжения и физическое макетирование. Результаты. Проведен анализ особенностей автономных систем электропитания, синтезирован закон управления и разработана модель импульсного стабилизатора напряжения. Предложен метод и найдены способы управления импульсными стабилизаторами напряжения, которые обеспечивают малую длительность переходных процессов и астатизм выходного напряжения. Разработаны алгоритмы микропрограммного управления, реализующие найденные способы управления. Разработана архитектура и встроенное программное обеспечение для микропроцессорной системы управления стабилизатором. Изготовлен однокристальный вычислительный модуль устройства управления на базе программируемой интегральной схемы. Разработан и изготовлен макет импульсного стабилизатора с цифровым управлением на основе однокристального вычислительного модуля. Результаты экспериментального исследования макета подтверждают эффективность разработанного устройства управления, а именно достижение минимальной конечной длительности переходных процессов, вызванных ступенчатым изменением тока нагрузки, близкой к двум периодам преобразования и астатизма выходного напряжения. Показано, что применение импульсного стабилизатора, использующего полностью цифровой контур управления и реализуемого при помощи высокоскоростных микропроцессорных средств, имеет значительные преимущества по сравнению с аналоговыми вариантами.

Programmable paper-based microfluidics device with prefabricated patterns for prototyping of µPADs

In this paper, a new programmable structure of paper-based analytical devices and its programming method are represented to be used for the purpose of rapid prototyping without involving the fabrication process. The proposed ready-to-program structure is prefabricated by the screen-printing method before rendering it to the end user. The users can prototype the device rapidly for their specific applications simply by programming the prefabricated device. The proposed programmable device is composed of three different layers patterned on the filter paper substrate including a hydrophobic barrier layer, a path-blocking layer and a heater network layer. The device programming procedure is totally electrical and it is implemented by applying proper DC voltages to several predetermined heater lines. This procedure is applicable manually or automatically using a programmer setup connected to a personal computer (PC). Therefore, the user can configure the device by selecting appropriate heater lines in a simple firmware through the PC. The proposed programmable structure is implemented in four different µPAD patterns for different applications. Biochemical assays of glucose, total protein and albumin are performed on the programmable devices to verify their applicability for bioassays.

Nanodomain Engineering for Programmable Ferroelectric Devices.

We introduce a concept of programmable ferroelectric devices composed of two-dimensional (2D) and ferroelectric (FE) materials. It enables precise modulation of the in-plane conductivity of a 2D channel material through nanoengineering FE domains with out-of-plane polarization. The functionality of these new devices has been demonstrated using field-effect transistors (FETs) fabricated with monolayer molybdenum disulfide (MoS2) channels on the Pb(Zr,Ti)O3 substrates. Using piezoresponse force microscopy (PFM), we show that local switching of FE polarization by a conductive probe can be used to tune the conductivity of the MoS2 channel. Specifically, patterning of the nanoscale domains with downward polarization creates conductive paths in a resistive MoS2 channel so that the conductivity of an FET is determined by the number and length of the paths connecting source and drain electrodes. In addition to the device programmability, we demonstrate the device ON/OFF cyclic endurance by successive writing and erasing of conductive paths in a MoS2 channel. These findings may inspire the development of advanced energy-efficient programmable synaptic devices based on a combination of 2D and FE materials.

Quantitative Analysis of Multistage Switching Networks for Embedded Programmable Devices

This paper analyzes the properties of a class of congestion-free multistage switching networks (MSSNs) are butterfly-based and suitable for embedded programmable devices, which require sustaining static multicast connectivity. These MSSNs are fully synthesizable and enable the design of programmable IPs with typical size in the order of 1 KLUT, coupling flexibility with fast turn-around time. The non-blocking property for static connection of this class of MSSN is discussed. Our analysis shows pros and cons of adopting radix-2 or radix-4 MSSN structures, as well as the impact of bypass-paths to make the network fully hierarchical and locality-aware thanks also to a dedicated programming strategy. Implementation experiments carried out on STM CMOS 65 nm technology show the availability of various area-speed trade-offs, resulting in a range of ≃2× in frequency and a range of ≃ 4 × in area. Depending on the specific application-field, an optimal interconnect definition is thus achieved without compromising the routability properties. In this respect, the paper proposes a simplified application-driven model for evaluation of the best MSSN, including bypass-adoption and radix selection.

Design Automation for Dilution of a Fluid Using Programmable Microfluidic Device--Based Biochips

Microfluidic lab-on-a-chip has emerged as a new technology for implementing biochemical protocols on small-sized portable devices targeting low-cost medical diagnostics. Among various efforts of fabrication of such chips, a relatively new technology is a programmable microfluidic device (PMD) for implementation of flow-based lab-on-a-chip. A PMD chip is suitable for automation due to its symmetric nature. In order to implement a bioprotocol on such a reconfigurable device, it is crucial to automate a sample preparation on-chip as well. In this article, we propose a dilution PMD algorithm (namely DPMD ) and its architectural mapping scheme (namely generalized architectural mapping algorithm ( GAMA )) for addressing fluidic cells of such a device to perform dilution of a reagent fluid on-chip. We used an optimization function that first minimizes the number of mixing steps and then reduces the waste generation and further reagent requirement. Simulation results show that the proposed DPMD scheme is comparative to the existing state-of-the-art dilution algorithm. The proposed design automation using the architectural mapping scheme reduces the required chip area and, hence, minimizes the valve switching that, in turn, increases the life span of the PMD-chip.

Electrically Programmable Terahertz Diatomic Metamolecules for Chiral Optical Control

Optical chirality is central to many industrial photonic technologies including enantiomer identification, ellipsometry-based tomography, and spin multiplexing in optical communications. However, a substantial chiral response requires a three-dimensional constituent, thereby making the morphology highly complex to realize structural reconfiguration. Moreover, an active reconfiguration demands intense dosage of external stimuli that pose a major limitation for on-chip integration. Here, we report a low bias, electrically programmable synthetic chiral paradigm with a remarkable reconfiguration among levorotatory, dextrorotatory, achiral, and racemic conformations. The switchable optical activity induced by the chiral conformations enables a transmission-type duplex spatial light modulator for terahertz single pixel imaging. The prototype delivers a new strategy towards reconfigurable stereoselective photonic applications and opens up avenues for on-chip programmable chiral devices with tremendous applications in biology, medicine, chemistry, and photonics.

Nanoscale Film Morphology and n‐Type Digital Memory Characteristics of π‐Conjugated Donor–Acceptor Alternating Copolymer Based on Thiophene and Thiadiazole Units

Various molecular weight π-conjugated donor-acceptor polymers based on thiadiazole and thiophene units are investigated with respect to nanoscale film morphology and digital memory performance. Interestingly, all polymers reveal excellent n-type digital permanent memory characteristics, which are governed by the combination of Ohmic and trap-limited space charge limited conductions via a hopping process using thiadiazole and thiophene units as charge traps and stepping stones. The digital memory performance is significantly influenced by the film morphology details that vary with the polymer molecular weight as well as the film thickness. A higher population of face-on structure formation, as well as higher molecular weight, provides a wider film thickness window of digital memory operation. Overall, π-conjugated PBTDzTV polymers are suitable for the production of high-performance, programmable n-type permanent memory devices with very low power consumption.

Synergy-Based FES for Post-Stroke Rehabilitation of Upper-Limb Motor Functions.

Functional electrical stimulation (FES) is capable of activating muscles that are under-recruited in neurological diseases, such as stroke. Therefore, FES provides a promising technology for assisting upper-limb motor functions in rehabilitation following stroke. However, the full benefits of FES may be limited due to lack of a systematic approach to formulate the pattern of stimulation. Our preliminary work demonstrated that it is feasible to use muscle synergy to guide the generation of FES patterns.In this paper, we present a methodology of formulating FES patterns based on muscle synergies of a normal subject using a programmable multi-channel FES device. The effectiveness of the synergy-based FES was tested in two sets of experiments. In experiment one, the instantaneous effects of FES to improve movement kinematics were tested in three patients post ischemic stroke. Patients performed frontal reaching and lateral reaching tasks, which involved coordinated movements in the elbow and shoulder joints. The FES pattern was adjusted in amplitude and time profile for each subject in each task. In experiment two, a 5-day session of intervention using synergy-based FES was delivered to another three patients, in which patients performed task-oriented training in the same reaching movements in one-hour-per-day dose. The outcome of the short-term intervention was measured by changes in Fugl-Meyer scores and movement kinematics. Results on instantaneous effects showed that FES assistance was effective to increase the peak hand velocity in both or one of the tasks. In short-term intervention, evaluations prior to and post intervention showed improvements in both Fugl-Meyer scores and movement kinematics. The muscle synergy of patients also tended to evolve towards that of the normal subject. These results provide promising evidence of benefits using synergy-based FES for upper-limb rehabilitation following stroke. This is the first step towards a clinical protocol of applying FES as therapeutic intervention in stroke rehabilitation.

Solar energy manager with PSOC5LP

In this document is presented the process of analyzing, designing and implementing of a solar energy manager controlled by programmable device CY8C5888LTI-LP097 PSoC 5LP. That makes possible the power measurement of generation, conversion and storage in the photovoltaic system, to take decisions about power supplying mode from the solar panels or the electrical network. Also to have a portable monitor with a tactile screen –connected via Bluetooth– it shows variables like: power consumed, generated and battery bank storage. This system sends data via Wi-Fi for the creation of a register in ThingSpeak data base. The energy manager accompanied by user and consumer control allows the power supply of diary basic devices in home by using a solar resource.