Light output measurements of the organic light-emitting devices

In this article we describe a novel light output measurements method of the organic light-emitting devices (OLEDs). This method not only provides the electroluminescence (EL) spectral response of the OLEDs, but also gives the spectral distribution of the radiant power (W), luminance (cd/m2),(cd/m2), luminous flux (lm), and photon emission of the measured light-emitting object. Also an accurate calculation method of the OLED EL external quantum efficiency is proposed. © 2000 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70764/2/RSINAK-71-5-2104-1.pd

High performance organic polymer light-emitting heterostructure devices

We report a high performance electroluminescence device based on bi-layer conjugated polymer structures consisting of a hole transporting (amine-fluorene) and an emissive (benzothiadiazole-fluorene) polymer layers prepared by the spin-coating technique on the glass substrate. Devices showed green emission with an electroluminescence peak located at around 545 nm and a full width at half maximum of about 80 nm. Our devices have also shown a high brightness ( ∼ 10 000(∼10000 cd/m2cd/m2 at 0.84 mA/mm2),mA/mm2), good emission efficiency ( ∼ 14.5(∼14.5 cd/A) and luminous efficiency (2.26 lm/W), a large external quantum efficiency (3.8%), and a reasonable forward-to-reverse bias current rectification ratio (>103(>103 at ±25±25 V). © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71009/2/APPLAB-74-16-2265-1.pd

Full‐Color Light‐Emitting Devices Based on π‐ and σ‐Conjugated Polymer Materials

Two kinds of full‐color light‐emitting devices have been fabricated using π‐ and σ‐conjugated polymers. One device is based on poly(bithiazole)'s, which have emission peaks ranging throughout visible region. The other device has a novel architecture in which ultraviolet‐light emitted by electroluminescent diode, based on an evaporated poly(dimethylsilane) layer, is converted by phosphors into visible light emission. The luminance of 0.2 cd/m 2 is obtained for a green light emitting device (injected current density of 0.8 mA/cm 2 and external quantum efficiency is calculated to be 0.0054%).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92062/1/1.1833847.pd

Under Seawater Capacitive Power Transfer for Maritime Charging Applications

Underwater capacitive power transfer (CPT) can provide an inexpensive and light electric charging solution with good misalignment tolerance for unmanned maritime vehicles. This paper investigates the effect of the changing of the frequency and the distance on the power transfer and overall efficiency of the underwater CPT system, considering the dielectric losses of the medium. It also proposes and validates a mathematical model for calculating the maximum available efficiency of the system. Using series compensations, the proposed CPT can transfer 48 W at 500 mm, 48 V input voltage, 516 kHz, and 54%

Insulin-like growth factor 1 prevents neuronal cell death and paraplegia in the rabbit model of spinal cord ischemia

AbstractObjective: Insulin-like growth factor 1 has been shown to be cytoprotective against ischemia-reperfusion injury in various organs. However, spinal cord protection by insulin-like growth factor 1 has not been tested. We have therefore examined the effect of insulin-like growth factor 1 on neuronal cell death and motor function after spinal cord ischemia. Methods: Japanese white rabbits were subjected to spinal cord ischemia by clamping the abdominal aorta for 15 minutes. Insulin-like growth factor 1 (0.3 mg/kg) at a dose equipotent to insulin (0.3 IU/kg) in lowering blood glucose level or the control (phosphate-buffered saline solution as a vehicle) was administered intravenously 30 minutes before the aortic clamp. Results: Hind-limb motor function had recovered normally 48 hours after the operation in all the rabbits (n = 8) treated with insulin-like growth factor 1. In contrast, all the control-treated (n = 8) and all but one of the insulin-treated (n = 6) rabbits had deteriorated to paraplegia by 48 hours after the operation. Histopathologic sections in the involved spinal cord segment showed that a significantly (P <.0001) greater number of motor neuron cells were preserved in the rabbits treated with insulin-like growth factor 1 (17.9 ± 4.8 per section) than in those treated with the control (8.0 ± 2.1). Although insulin was equipotent to insulin-like growth factor 1 in preserving the number of motor neuron cells (18.5 ± 2.7), the percentage of motor neuron cells positive for terminal deoxynucleotidyltransferase–mediated deoxyuridine triphosphate-biotin nick-end labeling were significantly (P <.01) smaller in the rabbits treated with insulin-like growth factor 1 (6.0 ± 4.6) compared with those treated with the control (54.6 ± 33.8) and insulin (26.2 ± 11.7). Immunohistochemical studies revealed that insulin-like growth factor 1 increased expression of the antiapoptotic Bcl-xL protein and inhibited expression of the proapoptotic Bax protein in motor neuron cells 24 and 48 hours after the operation. In contrast, expression of only Bax was increased after the operation in other groups of rabbits subjected to spinal cord ischemia. Conclusions: These results suggest that insulin-like growth factor 1, but not insulin with a conventional dose, protects motor neuron cells from ischemic spinal cord injury associated with differential regulation of Bcl-xL and Bax protein.J Thorac Cardiovasc Surg 2001;122:136-4

Design Considerations of Capacitive Power Transfer Systems

Capacitive power transfer (CPT) is a near-field wireless power transfer (WPT) technology that has attracted attention in different charging applications. By utilizing electric fields, CPT gives charging systems advantages in terms of cost, weight, flexibility, and mobility. This paper surveys a number of empirical published works in a period between 2015 and 2023. Additionally, it discusses theoretical and practical design considerations of a CPT system to understand and improve the technology and its applications. The paper studies the one- and two-port measuring approaches using vector network analyzers to determine the coupling parameters and compares the measurements to the simulated values using COMSOL Multiphysics ©. The two-port approach gives more accurate results than the one-port approach. The paper designs and tests a 13.56MHz CPT system using the two-port measurement results. The system transfers 100W at 87.4% efficiency and 30mm separation distance. Lastly, the paper discusses the design limitations and challenges of the CPT systems, aiming to emphasize the design obstacles that can drive the advancement of the CPT systems for wireless charging applications

Potential role of vacuolar H+–adenosine triphosphatase in neointimal formation in cultured human saphenous vein

AbstractObjective: Vacuolar H+–adenosine triphosphatase plays a pivotal role in pH regulation and molecular transport across the vacuolar membranes and is involved in cell proliferation and transformation. In the present study, possible involvement of vacuolar H+–adenosine triphosphatase in neointimal formation was investigated in an organ culture model of human saphenous vein. Methods and results: Cultured saphenous vein segments developed neointimal formation and marked thickening of the media within 14 days. Neointimal formation and medial thickening were completely inhibited by 10 nmol/L bafilomycin A1, a selective inhibitor of vacuolar H+-adenosine triphosphatase, although structurally related macrolide antibiotics FK-506 and erythromycin were without an effect. The neointimal cells were positive for α-smooth muscle actin and vimentin but negative for desmin, indicative of myofibroblasts. The emergence of myofibroblasts was inhibited, and endothelial cells were preserved in the saphenous vein segments treated with bafilomycin A1. Uptake of bromodeoxyuridine, a proliferation marker, by myofibroblasts was abrogated in the saphenous vein segments treated with 10 nmol/L bafilomycin A1. Detection of apoptotic cells by terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling concomitant with identification of desmin-expressing smooth muscle cells demonstrated that neointimal myofibroblasts, but not medial smooth muscle cells, that expressed desmin underwent apoptosis by treatment with bafilomycin A1. Conclusions: These results suggest that vacuolar H+–adenosine triphosphatase may be involved in myofibroblast growth that contributes to neointimal formation and medial thickening in cultured human saphenous vein. Increased sensitivity of myofibroblasts, but not endothelial cells, and differentiated smooth muscle cells to bafilomycin A1 may have potential therapeutic implications in the treatment for vein graft disease. (J Thorac Cardiovasc Surg 2000;119:998-1007

Study of Contact Resistance on Organic Thin-Film Transistor with Surface Treatments

In organic thin-film transistors (OTFT), the fabrication processes such as surface treatment method, substrate temperature and deposition rate give significant effects on TFT device performance. We have investigated the variation of electrical performance on DNTT-based OTFT devices influenced by the fabrication processes. The DNTT films deposited on HMDS-treated SiO_2 substrates at the substrate temperature of 60℃, resulting in high OTFT performance with mobility greater than 0.56cm^2/(V・s) and I_<on>/I_<off> greater than of 10^6. In addition, the prominent decrease of contact resistance to almost a one-tenth or less is observed from influence of surface treatment process