There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Molecular self-assembly is the spontaneous association of molecules under equilibrium conditions into stable, structurally well-defined aggregates joined by noncovalent bonds. Molecular self-assembly is ubiquitous in biological systems and underlies the formation of a wide variety of complex biological structures. Understanding self-assembly and the associated noncovalent interactions that connect complementary interacting molecular surfaces in biological aggregates is a central concern in structural biochemistry. Self-assembly is also emerging as a new strategy in chemical synthesis, with the potential of generating nonbiological structures with dimensions of 1 to 10(2) nanometers (with molecular weights of 10(4) to 10(10) daltons). Structures in the upper part of this range of sizes are presently inaccessible through chemical synthesis, and the ability to prepare them would open a route to structures comparable in size (and perhaps complementary in function) to those that can be prepared by microlithography and other techniques of microfabrication.

Molecular self-assembly and nanochemistry: A chemical strategy for the synthesis of nanostructures

Zinc oxide can be called a multifunctional material thanks to its unique physical and chemical properties. The first part of this paper presents the most important methods of preparation of ZnO divided into metallurgical and chemical methods. The mechanochemical process, controlled precipitation, sol-gel method, solvothermal and hydrothermal method, method using emulsion and microemulsion enviroment and other methods of obtaining zinc oxide were classified as chemical methods. In the next part of this review, the modification methods of ZnO were characterized. The modification with organic (carboxylic acid, silanes) and inroganic (metal oxides) compounds, and polymer matrices were mainly described. Finally, we present possible applications in various branches of industry: rubber, pharmaceutical, cosmetics, textile, electronic and electrotechnology, photocatalysis were introduced. This review provides useful information for specialist dealings with zinc oxide.

Zinc Oxide-From Synthesis to Application: A Review.

Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption

Fiber‐Based Wearable Electronics: A Review of Materials, Fabrication, Devices, and Applications

High quality vertically aligned ZnO nanorods (NRs) were grown by low-temperature aqueous chemical technique on 4H-n-SiC substrates. Schottky light-emitting diodes (LEDs) were fabricated. The current-voltage (I–V) characteristics of Schottky diodes reveal good rectifying behavior. Optical properties of the ZnO nanorods (NRs) were probed by cathodoluminescence (CL) measurements at room temperature complemented with electroluminescence (EL). The room-temperature CL spectra of the ZnO NRs exhibit near band edge (NBE) emission as well as strong deep level emission (DLE) centered at 690 nm. At room temperature the CL spectra intensity of the DLE was enhanced with the increase of the electron beam penetration depth due to the increase of defect concentration at the interface and due to the conversion of self-absorbed UV emission. We observed a variation in the DLE along the nanorod depth. This indicates a relatively lower structural quality near the interface between ZnO NRs and n-SiC substrate. The room-temperature CL spectra of SiC show very weak emission, which confirms that most of the DLE is originating from the ZnO NRs, and SiC has a minute contribution to the emission.

Study of Au/ZnO nanorods Schottky light-emitting diodes grown by low-temperature aqueous chemical method

The study of the optical properties of zinc oxide (ZnO) nanorods and its composite nanostructures is an appealing issue in order to have highly efficient optoelectronic devices in the future. Zinc oxide, copper oxide (CuO) and their composite nanostructures were grown by the hydrothermal growth technique. The structural properties of the grown ZnO, CuO and their composite NSs were investigated by scanning electron microscopy and X-ray diffraction techniques. UV-visible spectroscopy, Cathodoluminescence and photoluminescence techniques were used for the study of optical properties of the as synthesized nanomaterials. X-ray photoelectron spectroscopy was used to measure the valence band offset of the CuO/ZnO composite nanostructures. Cathodoluminescence study of pure ZnO nanorods showed more insight for lateral luminescence compared to the top surface of the nanorods which opened a novel investigation in the area of optical properties of ZnO nanomaterial. While the room temperature cathodoluminescence spectra of CuO/ZnO composite nanostructures have demonstrated excellent luminescence in the UV region compared to the cathodoluminescence spectra observed at 4 K. The measured values for valence band offset and conduction band offset are found to be 2.83 eV and 0.73 eV, respectively for the prepared CuO/ZnO composite nanostructures. It was observed that CuO/ZnO composite nanostructures have type-II band alignment. The conclusion from both the cathodoluminescence and the photoluminescence studies showed that the luminescence in the visible region is only originated from the ZnO nanomaterial and that the CuO absorbs this visible emission as it covers the ZnO. This provides evidence suggesting that the use of CuO/ZnO in the fabrication of LEDs in the visible range is not appropriate.

Synthesis of CuO/ZnO Composite Nanostructures, Their Optical Characterization and Valence Band Offset Determination by X-Ray Photoelectron Spectroscopy

High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M=Ag, Cd and Ni) heterojunction based ultraviolet photodiodes

In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10−6 M to 10−3 M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

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Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties.

Single crystalline hexagonal wurtzite zinc oxide nanowires were grown on conductive commercial textile fabric as piezoelectric material. Aqueous chemical growth (ACG) method was used for the synthe ...

Omer Nur

Papers

Study of Au/ZnO nanorods Schottky light-emitting diodes grown by low-temperature aqueous chemical method

Synthesis of CuO/ZnO Composite Nanostructures, Their Optical Characterization and Valence Band Offset Determination by X-Ray Photoelectron Spectroscopy

High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M=Ag, Cd and Ni) heterojunction based ultraviolet photodiodes

Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties.

Analysis of direct and converse piezoelectric responses from zinc oxide nanowires grown on a conductive fabric