Showing papers by "Samsung published in 2013"

Grains and grain boundaries in highly crystalline monolayer molybdenum disulphide

Abstract: Despite recent progress in the synthesis and characterization of molybdenum disulphide, little is yet known about its microstructure. Using refined chemical vapour deposition synthesis, high-quality crystals of monolayer molybdenum disulphide have now been grown. Single-crystal islands and polycrystals containing tilt and mirror twin grain boundaries are characterized, and the influence of the grain boundaries on the material properties of molybdenum disulphide is assessed.

Selective Gas Transport Through Few-Layered Graphene and Graphene Oxide Membranes

Abstract: Graphene is a distinct two-dimensional material that offers a wide range of opportunities for membrane applications because of ultimate thinness, flexibility, chemical stability, and mechanical strength. We demonstrate that few- and several-layered graphene and graphene oxide (GO) sheets can be engineered to exhibit the desired gas separation characteristics. Selective gas diffusion can be achieved by controlling gas flow channels and pores via different stacking methods. For layered (3- to 10-nanometer) GO membranes, tunable gas transport behavior was strongly dependent on the degree of interlocking within the GO stacking structure. High carbon dioxide/nitrogen selectivity was achieved by well-interlocked GO membranes in high relative humidity, which is most suitable for postcombustion carbon dioxide capture processes, including a humidified feed stream.

API design for machine learning software: experiences from the scikit-learn project

Abstract: Scikit-learn is an increasingly popular machine learning li- brary. Written in Python, it is designed to be simple and efficient, accessible to non-experts, and reusable in various contexts. In this paper, we present and discuss our design choices for the application programming interface (API) of the project. In particular, we describe the simple and elegant interface shared by all learning and processing units in the library and then discuss its advantages in terms of composition and reusability. The paper also comments on implementation details specific to the Python ecosystem and analyzes obstacles faced by users and developers of the library.

Flexible and Transparent MoS2 Field-Effect Transistors on Hexagonal Boron Nitride-Graphene Heterostructures

Abstract: Atomically thin forms of layered materials, such as conducting graphene, insulating hexagonal boron nitride (hBN), and semiconducting molybdenum disulfide (MoS2), have generated great interests recently due to the possibility of combining diverse atomic layers by mechanical “stacking” to create novel materials and devices. In this work, we demonstrate field-effect transistors (FETs) with MoS2 channels, hBN dielectric, and graphene gate electrodes. These devices show field-effect mobilities of up to 45 cm2/Vs and operating gate voltage below 10 V, with greatly reduced hysteresis. Taking advantage of the mechanical strength and flexibility of these materials, we demonstrate integration onto a polymer substrate to create flexible and transparent FETs that show unchanged performance up to 1.5% strain. These heterostructure devices consisting of ultrathin two-dimensional (2D) materials open up a new route toward high-performance flexible and transparent electronics.

Metallic anodes for next generation secondary batteries.

Abstract: Li–air(O2) and Li–S batteries have gained much attention recently and most relevant research has aimed to improve the electrochemical performance of air(O2) or sulfur cathode materials. However, many technical problems associated with the Li metal anode have yet to be overcome. This review mainly focuses on the electrochemical behaviors and technical issues related to metallic Li anode materials as well as other metallic anode materials such as alkali (Na) and alkaline earth (Mg) metals, including Zn and Al when these metal anodes were employed for various types of secondary batteries.

High-Performance, Transparent, and Stretchable Electrodes Using Graphene–Metal Nanowire Hybrid Structures

Abstract: Transparent electrodes that can remain electrically conductive and stable under large mechanical deformations are highly desirable for applications in flexible and wearable electronics. This paper describes a comprehensive study of the electrical, optical, and mechanical properties of hybrid nanostructures based on two-dimensional graphene and networks of one-dimensional metal nanowires, and their use as transparent and stretchable electrodes. Low sheet resistance (33 Ω/sq) with high transmittance (94% in visible range), robust stability against electric breakdown and oxidation, and superb flexibility (27% in bending strain) and stretchability (100% in tensile strain) are observed, and these multiple functionalities of the hybrid structures suggest a future promise for next generation electronics. The use of hybrid electrodes to fabricate oxide semiconductor transistors and single-pixel displays integrated on wearable soft contact lenses with in vivo tests are demonstrated.

Phase stability, electrochemical stability and ionic conductivity of the Li10±1MP2X12 (M = Ge, Si, Sn, Al or P, and X = O, S or Se) family of superionic conductors

Abstract: We present an investigation of the phase stability, electrochemical stability and Li+ conductivity of the Li10±1MP2X12 (M = Ge, Si, Sn, Al or P, and X = O, S or Se) family of superionic conductors using first principles calculations. The Li10GeP2S12 (LGPS) superionic conductor has the highest Li+ conductivity reported to date, with excellent electrochemical performance demonstrated in a Li-ion rechargeable battery. Our results show that isovalent cation substitutions of Ge4+ have a small effect on the relevant intrinsic properties, with Li10SiP2S12 and Li10SnP2S12 having similar phase stability, electrochemical stability and Li+ conductivity as LGPS. Aliovalent cation substitutions (M = Al or P) with compensating changes in the Li+ concentration also have a small effect on the Li+ conductivity in this structure. Anion substitutions, however, have a much larger effect on these properties. The oxygen-substituted Li10MP2O12 compounds are predicted not to be stable (with equilibrium decomposition energies >90 meV per atom) and have much lower Li+ conductivities than their sulfide counterparts. The selenium-substituted Li10MP2Se12 compounds, on the other hand, show a marginal improvement in conductivity, but at the expense of reduced electrochemical stability. We also studied the effect of lattice parameter changes on the Li+ conductivity and found the same asymmetry in behavior between increases and decreases in the lattice parameters, i.e., decreases in the lattice parameters lower the Li+ conductivity significantly, while increases in the lattice parameters increase the Li+ conductivity only marginally. Based on these results, we conclude that the size of the S2− is near optimal for Li+ conduction in this structural framework.

Method for transmitting and receiving data between memo layer and application and electronic device using the same

Abstract: A method for transmitting and receiving data between a memo layer and an application and an electronic device using the same are provided. The method includes executing an application and displaying the executed application on a touch screen, detecting a gesture on the touch screen during execution of the application, displaying a memo layer overlapped on the application according to the detected gesture, the memo layer including a handwriting input area for displaying data to be provided to the application and a display area for displaying data received from the application, receiving a handwriting image in the handwriting input area of the memo layer, recognizing the received handwriting image and comparing the recognized handwriting image with preset data, and displaying a feedback received from the application in the display area of the memo layer according to a comparison result.

Analytical Modeling of Uplink Cellular Networks

Abstract: Cellular uplink analysis has typically been undertaken by either a simple approach that lumps all interference into a single deterministic or random parameter in a Wyner-type model, or via complex system level simulations that often do not provide insight into why various trends are observed. This paper proposes a novel middle way using point processes that is both accurate and also results in easy-to-evaluate integral expressions based on the Laplace transform of the interference. We assume mobiles and base stations are randomly placed in the network with each mobile pairing up to its closest base station. Compared to related recent work on downlink analysis, the proposed uplink model differs in two key features. First, dependence is considered between user and base station point processes to make sure each base station serves a single mobile in the given resource block. Second, per-mobile power control is included, which further couples the transmission of mobiles due to location-dependent channel inversion. Nevertheless, we succeed in deriving the coverage (equivalently outage) probability of a typical link in the network. This model can be used to address a wide variety of system design questions in the future. In this paper we focus on the implications for power control and show that partial channel inversion should be used at low signal-to-interference-plus-noise ratio (SINR), while full power transmission is optimal at higher SINR.

Organic light-emitting display device and method of manufacturing the same

Abstract: An organic light-emitting display device includes a thin film transistor (TFT) including an active layer, a gate electrode, a source electrode, and a drain electrode, the thin film transistor includes at least one of a switching TFT and a driving TFT A pixel electrode is connected to one of the source electrode or the drain electrode An auxiliary electrode is spaced apart from the TFT and the pixel electrode An intermediate layer is disposed on at least a portion of the pixel electrode and on at least a portion of the auxiliary electrode A first electrode is disposed on at least a portion of the intermediate layer and on at least a portion of the auxiliary electrode A second electrode, which directly contacts an upper surface of the auxiliary electrode, is disposed on the first electrode A contact hole exposes at least a portion of the auxiliary electrode

Basic principles of STT-MRAM cell operation in memory arrays

Abstract: For reliable operation, individual cells of an STT-MRAM memory array must meet specific requirements on their performance. In this work we review some of these requirements and discuss the fundamental physical principles of STT-MRAM operation, covering the range from device level to chip array performance, and methodology for its development.

Matching domain-wall configuration and spin-orbit torques for efficient domain-wall motion

Abstract: In our numerical study, we identify the best conditions for efficient domain-wall motion by spin-orbit torques originating from the spin Hall effect or Rashba effect. We demonstrate that the effect depends critically on the domain-wall configuration, the current injection scheme, and the symmetry of the spin-orbit torque. The best identified configuration corresponds to a N\'eel wall driven by the spin Hall effect in a narrow strip with perpendicular magnetic anisotropy. In this case, the domain-wall velocity can be a factor of 10 larger than that for the conventional current-in-plane spin-transfer torque.

Non-orthogonal Multiple Access in a Downlink Multiuser Beamforming System

Abstract: In this paper, we propose a non-orthogonal multiple access-based multiuser beamforming (NOMA-BF) system designed to enhance the sum capacity. In the proposed NOMA-BF system, a single BF vector is shared by two users, so that the number of supportable users can be increased. However, sharing a BF vector leads to interference from other beams as well as from the other user sharing the BF vector. Therefore, to reduce interference and improve the sum capacity, we additionally propose a clustering and power allocation algorithm. This clustering algorithm, which selects two users with high correlation and a large gain-difference between their channels, can reduce the interference from other beams and from the other user as well. Furthermore, power allocation ensures that each user's transmit power is allocated so as to maximize the sum capacity. Numerical results verify that the proposed NOMA-BF system improves the sum capacity, compared to the conventional multiuser BF system.

Randomized, Multicenter, Open-Label Study of Oxaliplatin Plus Fluorouracil/Leucovorin Versus Doxorubicin As Palliative Chemotherapy in Patients With Advanced Hepatocellular Carcinoma From Asia

Abstract: Purpose To determine whether FOLFOX4 (infusional fluorouracil, leucovorin, and oxaliplatin) administered as palliative chemotherapy to patients with advanced hepatocellular carcinoma (HCC) provides a survival benefit and efficacy versus doxorubicin. Patients and Methods This multicenter, open-label, randomized, phase III study in mainland China, Taiwan, Korea, and Thailand involved 371 patients age 18 to 75 years who had locally advanced or metastatic HCC and were ineligible for curative resection or local treatment. They were randomly assigned at a ratio of one to one to receive either FOLFOX4 (n = 184) or doxorubicin (n = 187). The primary end point was overall survival (OS); secondary end points included progression-free survival (PFS), response rate (RR) by RECIST (version 1.0), and safety. Results At the prespecified final analysis, median OS was 6.40 months with FOLFOX4 (95% CI, 5.30 to 7.03) and 4.97 months with doxorubicin (95% CI, 4.23 to 6.03; P = .07; hazard ratio [HR], 0.80; 95% CI, 0.63 to 1....

Restacking-Inhibited 3D Reduced Graphene Oxide for High Performance Supercapacitor Electrodes

Abstract: Graphene has received considerable attention in both scientific and technological areas due to its extraordinary material properties originating from the atomically single- or small number-layered structure. Nevertheless, in most scalable solution-based syntheses, graphene suffers from severe restacking between individual sheets and thus loses its material identity and advantages. In the present study, we have noticed the intercalated water molecules in the dried graphene oxide (GO) as a critical mediator to such restacking and thus eliminated the hydrogen bonding involving the intercalated water by treating GO with melamine resin (MR) monomers. Upon addition of MR monomers, porous restacking-inhibited GO sheets precipitated, leading to the carbonaceous composite with an exceptionally large surface area of 1040 m2/g after a thermal treatment. Utilizing such high surface area, the final graphene composite exhibited excellent electrochemical performance as a supercapacitor electrode material: specific capac...

Full-dimension MIMO (FD-MIMO) for next generation cellular technology

Abstract: This article considers a practical implementation of massive MIMO systems [1]. Although the best performance can be achieved when a large number of active antennas are placed only in the horizontal domain, BS form factor limitation often makes horizontal array placement infeasible. To cope with this limitation, this article introduces full-dimension MIMO (FD-MIMO) cellular wireless communication system, where active antennas are placed in a 2D grid at BSs. For analysis of the FD-MIMO systems, a 3D spatial channel model is introduced, on which system-level simulations are conducted. The simulation results show that the proposed FD-MIMO system with 32 antenna ports achieves 2-3.6 times cell average throughput gain and 1.5-5 times cell edge throughput gain compared to the 4G LTE system of two antenna ports at the BS.

Method and apparatus for performing synchronization in device-to-device network

Abstract: A method and an apparatus for performing synchronization by a first device in a Device-to-Device (D2D) network are provided. The method includes detecting a synchronization signal from at least one second device during one period, determining a phase adjustment value depending on a number of synchronization signals, which have been detected from the at least one second device during the one period, adjusting a phase value of a first device using the phase adjustment value, and transmitting a synchronization signal if the phase value of the first device reaches a predetermined specific value.

API design for machine learning software: experiences from the scikit-learn project

Abstract: Scikit-learn is an increasingly popular machine learning li- brary. Written in Python, it is designed to be simple and efficient, accessible to non-experts, and reusable in various contexts. In this paper, we present and discuss our design choices for the application programming interface (API) of the project. In particular, we describe the simple and elegant interface shared by all learning and processing units in the library and then discuss its advantages in terms of composition and reusability. The paper also comments on implementation details specific to the Python ecosystem and analyzes obstacles faced by users and developers of the library.

Light emitting device, light emitting system having the same, and fabricating method of the light emitting device and the light emitting system

Abstract: A semiconductor device includes a first light emitting chip, the first light emitting chip having a first semiconductor layer, a second semiconductor layer, and a first active layer disposed therebetween, a second light emitting chip disposed on the first light emitting chip, the second light emitting chip having a third semiconductor layer, a fourth semiconductor layer, and a second active layer disposed therebetween, and a conductive layer disposed between the first semiconductor layer and the fourth semiconductor layer, the first semiconductor layer and the fourth semiconductor layer having different conductivity types.

Foldable display device

Abstract: A foldable display device includes a flexible display panel, a case supporting the flexible display panel, a bonding member fixing the flexible display panel to the case. The case includes a hinge portion, and supports respectively coupled to the hinge portion at opposing sides of the hinge portion. The flexible display panel includes a bendable area corresponding to the hinge portion, and planar areas respectively at opposing sides of the bendable area and corresponding to the supports of the case. The bonding member is between a support of the case and the corresponding planar area of the flexible display panel, and is displaceable with respect to the support along one of a thickness direction and a width direction of the flexible display panel when the flexible display panel is folded.

Wearable electronic device

Abstract: In one embodiment, a device includes a device body that includes a touch-sensitive display and a processor. The device also includes a band coupled to the device body and an optical sensor in or on the band. The optical sensor faces outward from the band and captures images. The processor communicates with the optical sensor to process captured images.

In situ observation of filamentary conducting channels in an asymmetric Ta2O5−x/TaO2−x bilayer structure

Abstract: Electrically induced resistive switching in metal insulator-metal structures is a subject of increasing scientific interest because it is one of the alternatives that satisfies current requirements for universal non-volatile memories. However, the origin of the switching mechanism is still controversial. Here we report the fabrication of a resistive switching device inside a transmission electron microscope, made from a Pt/SiO₂/a-Ta₂O5-x/a-TaO2-x/Pt structure, which clearly shows reversible bipolar resistive switching behaviour. The current-voltage measurements simultaneously confirm each of the resistance states (set, reset and breakdown). In situ scanning transmission electron microscope experiments verify, at the atomic scale, that the switching effects occur by the formation and annihilation of conducting channels between a top Pt electrode and a TaO2-x base layer, which consist of nanoscale TaO1-x filaments. Information on the structure and dimensions of conductive channels observed in situ offers great potential for designing resistive switching devices with the high endurance and large scalability.

A Novel Layer Jamming Mechanism With Tunable Stiffness Capability for Minimally Invasive Surgery

Abstract: This paper presents a novel “layer jamming” mechanism that can achieve variable stiffness. The layer jamming mechanism exploits the friction present between layers of thin material, which can be controlled by a confining pressure. Due to the mechanism's hollow geometry, compact size, and light weight, it is well suited for various minimally invasive surgery applications, where stiffness change is required. This paper describes the concept, the mathematical model, and a tubular snake-like manipulator prototype. Various characteristics of layer jamming, such as stiffness and yield strength, are studied both theoretically and experimentally.

Modeling precision treatment of breast cancer

Abstract: Background: First-generation molecular profiles for human breast cancers have enabled the identification of features that can predict therapeutic response; however, little is known about how the various data types can best be combined to yield optimal predictors. Collections of breast cancer cell lines mirror many aspects of breast cancer molecular pathobiology, and measurements of their omic and biological therapeutic responses are well-suited for development of strategies to identify the most predictive molecular feature sets. Results: We used least squares-support vector machines and random forest algorithms to identify molecular features associated with responses of a collection of 70 breast cancer cell lines to 90 experimental or approved therapeutic agents. The datasets analyzed included measurements of copy number aberrations, mutations, gene and isoform expression, promoter methylation and protein expression. Transcriptional subtype contributed strongly to response predictors for 25% of compounds, and adding other molecular data types improved prediction for 65%. No single molecular dataset consistently out-performed the others, suggesting that therapeutic response is mediated at multiple levels in the genome. Response predictors were developed and applied to TCGA data, and were found to be present in subsets of those patient samples. Conclusions: These results suggest that matching patients to treatments based on transcriptional subtype will improve response rates, and inclusion of additional features from other profiling data types may provide additional benefit. Further, we suggest a systems biology strategy for guiding clinical trials so that patient cohorts most likely to respond to new therapies may be more efficiently identified.

Method and apparatus for transmitting and receiving data using plurality of carriers in mobile communication system

Abstract: The present invention relates to a method and apparatus for performing a discontinuous reception (DRX) operation while transceiving data using a plurality of carriers in a mobile communication system. The communication method for a terminal according to one embodiment of the present invention comprises the steps of: receiving a control message, including setting information of a secondary serving cell (SCell) to be added and discontinuous reception setting information, from a primary serving cell (PCell); and applying, if the control message includes an indicator indicating that the first base station to which the SCell to be added belongs and the second base station to which the PCell belongs are different from each other, the DRX setting information to the serving cell of a first base station. According to one embodiment of the present invention, a discontinuous reception (DRX) operation is applied upon the occurrence of inter-base-station carrier aggregation, thus reducing the consumption of a battery.

Jalangi: a selective record-replay and dynamic analysis framework for JavaScript

Abstract: JavaScript is widely used for writing client-side web applications and is getting increasingly popular for writing mobile applications. However, unlike C, C++, and Java, there are not that many tools available for analysis and testing of JavaScript applications. In this paper, we present a simple yet powerful framework, called Jalangi, for writing heavy-weight dynamic analyses. Our framework incorporates two key techniques: 1) selective record-replay, a technique which enables to record and to faithfully replay a user-selected part of the program, and 2) shadow values and shadow execution, which enables easy implementation of heavy-weight dynamic analyses. Our implementation makes no special assumption about JavaScript, which makes it applicable to real-world JavaScript programs running on multiple platforms. We have implemented concolic testing, an analysis to track origins of nulls and undefined, a simple form of taint analysis, an analysis to detect likely type inconsistencies, and an object allocation profiler in Jalangi. Our evaluation of Jalangi on the SunSpider benchmark suite and on five web applications shows that Jalangi has an average slowdown of 26X during recording and 30X slowdown during replay and analysis. The slowdowns are comparable with slowdowns reported for similar tools, such as PIN and Valgrind for x86 binaries. We believe that the techniques proposed in this paper are applicable to other dynamic languages.

Highly Efficient, Color-Pure, Color-Stable Blue Quantum Dot Light-Emitting Devices

Abstract: For colloidal quantum dot light-emitting diodes (QD-LEDs), blue emissive device has always been inferior to green and red counterparts with respect to device efficiency, primarily because blue QDs possess inherently unfavorable energy levels relative to green and red ones, rendering hole injection to blue QDs from neighboring hole transport layer (HTL) inefficient. Herein, unprecedented synthesis of blue CdZnS/ZnS core/shell QDs that exhibit an exceptional photoluminescence (PL) quantum yield of 98%, extraordinarily large size of 11.5 nm with a shell thickness of 2.6 nm, and high stability against a repeated purification process is reported. All-solution-processed, multilayered blue QD-LEDs, consisting of an HTL of poly(9-vinlycarbazole), emissive layer of CdZnS/ZnS QDs, and electron transport layer of ZnO nanoparticles, are fabricated. Our best device displays not only a maximum luminance of 2624 cd/m2, luminous efficiency of 2.2 cd/A, and external quantum efficiency of 7.1%, but also no red-shift and br...

Synthesis of chemically bonded graphene/carbon nanotube composites and their application in large volumetric capacitance supercapacitors.

Abstract: Chemically bonded graphene/carbon nanotube composites as flexible supercapacitor electrode materials are synthesized by amide bonding. Carbon nanotubes attached along the edges and onto the surface of graphene act as spacers to increase the electrolyte-accessible surface area. Our lamellar structure electrodes demonstrate the largest volumetric capacitance (165 F cm(-3) ) ever shown by carbon-based electrodes.