Controllable Shape Evolution of Cu2O Flowers and Their Morphologies-Dependent Selective CO Oxidation

Nano LIFE ◽  
2014 ◽  
Vol 04 (03) ◽  
pp. 1441004
Author(s):  
Daoli Zhao ◽  
Xuefei Guo ◽  
Yuchuan Zheng ◽  
Linlin Wang ◽  
Qing Yang

The flower-like Cu 2 O nanostructures were hydrothermally synthesized without using any template or surfactant. The influences of hydrothermal temperature, reaction time and reactants concentrations on the growth of nanostructures were investigated in detail. The samples were characterized by scanning electron microscope (SEM) and X-ray powder diffraction (XRD). Cu 2 O crystals with different shapes, i.e., flower-like (F-product) cubic box (CB-product) and cubic box with holes in each face (CBH-product), were synthesized by controlling the synthesis parameters and explored for CO catalytic oxidation. It was found that F-product showed higher catalytic than others.

2015 ◽  
Vol 723 ◽  
pp. 544-547
Author(s):  
Xiang Wei Cheng ◽  
Da Jin Xiong ◽  
Chao Huo

Using intermittent bubbling carbonation method to prepare nanoCaCO3, the effect of crystal orientation agents on the morphology of nanoCaCO3 was studied. The nanoCaCO3 was characterized by means of field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), Laser particle analyzer. The results showed that the different shapes nanoCaCO3 was synthesized by adding different crystal orientation agents to control the shape of the product. The as-prepared CaCO3 were pure calcite crystal and the average particle sizes were within the range of 25.7 to 60.9 nm.


2013 ◽  
Vol 28 (S2) ◽  
pp. S315-S326 ◽  
Author(s):  
Ravinder Singh Joshi ◽  
Harpreet Singh

In present investigation, effect of modulation and machining parameters on deformation level of the chips produced during modulation assisted machining (MAM) has been studied. It is shown that disruption in tool-chip contact during modulation assisted machining helps in the formation of discrete chips. Size and shape of the particles produced in MAM can be controlled by varying modulation and machining conditions. Particulates of different shapes and sizes ranging from 100 µm to 5 mm with an aspect ratio of ~10 were produced using MAM. The morphology of the particulates produced was characterized by scanning electron microscope (SEM). Deformation in chip particulates was investigated using X-Ray diffraction. The crystallite size and internal strain in particulates were evaluated using Scherrer and Williamson-Hall methods respectively. The crystallite size of the particulates was found to decrease with decrease in their size, whereas internal strain in particulates was observed to increase with decrease in their size. Furthermore, the length of particulates was observed to decrease with an increase in the ratio of frequency of modulation (fm) to frequency of workpiece rotation (fw). However, the corresponding change in microstrain and crystallite size was insignificant with change in this ratio.


2012 ◽  
Vol 159 ◽  
pp. 376-379 ◽  
Author(s):  
Xiao Ming Fu

β-Ni(OH)2 nanospheres and nanoflakes have been successfully synthesized with nickel nitrate as nickel source and stronger ammonia water as precipitant via the hydrothermal method. The phase and the morphologies of the samples have been characterized and analyzed by XRD (X-ray diffraction) and SEM (Scanning electron microscope), respectively. XRD analysis shows that the phase of the samples is β-Ni(OH)2. SEM analysis confirms that the low reaction temperature is propitious to the synthesis of β-Ni(OH)2 nanospheres. However, The high temperature is in favor of the synthesis of β-Ni(OH)2 nanosflakes.


2011 ◽  
Vol 236-238 ◽  
pp. 362-368
Author(s):  
Jin Hong Li ◽  
Zhen Qing Chi ◽  
Hui Fen Chen

NaY zeolite molecular sieves have been synthesized using diatomite as a main starting material via a hydrothermal method. In this approach, the mixture of diatomite and Na2CO3 in mass ratio of 1.0/1.46 was first calcined at temperature of 830 °C for about 1.5 h. The calcined materials were then dissolved in water to obtain a solution and the composition is 15.1 Na2O : 1 Al2O3 : 11.5 SiO2 : 832 H2O. The solution was used to synthesize NaY zeolite by the crystals seeds (27.76Na2O·1.00Al2O3·25.07SiO2·305.66H2O) via hydrothermal treatment. The hydrothermal temperature is 100 °C and the percentage of added crystal seeds is 10% (volume) relative to calcined materials. The obtained zeolite was identified by X-ray diffraction (XRD), and was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and nitrogen sorption analysis, which showed that a high yield of NaY type with a high crystalinity was obtained.


2011 ◽  
Vol 197-198 ◽  
pp. 1057-1063
Author(s):  
Xiao Hua Liu ◽  
Hai Xin Bai ◽  
Lin Zhou

A novel porous CaO microsphere catalyst was synthesized by calcining spherical CaCO3 precursor which was prepared easily by mixing CaCl2 with Na2CO3. After characterized by scanning electron microscope and X-ray diffraction analysis, the synthesized CaO was studied on Studies on the catalyzing transesterification of soybean oil with methanol for biodiesel. The effects of calcining temperature, reaction time and temperature, amounts of catalyst and methanol on the catalytic activity of CaO microsphere had been evaluated by catalyzing transesterification of soybean oil with methanol for biodiesel. It expressed excellent catalytic activity with a transesterification yield of more than 98% at 65 °C in one hour with 3 wt% of CaO microsphere calcined at 800 °C.


Author(s):  
W. Brünger

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


Arena Tekstil ◽  
2013 ◽  
Vol 28 (1) ◽  
Author(s):  
Maya Komalasari ◽  
Bambang Sunendar

Partikel nano TiO2 berbasis air dengan pH basa telah berhasil disintesis dengan menggunakan metode sol-gel dan diimobilisasi pada kain kapas dengan menggunakan kitosan sebagai zat pengikat silang. Sintesis dilakukan  dengan prekursor TiCl4 pada konsentrasi 0,3 M, 0,5 M dan 1 M, dan menggunakan templat kanji dengan proses kalsinasi pada suhu 500˚C selama 2 jam. Partikel nano TiO2 diaplikasikan ke kain kapas dengan metoda pad-dry-cure dan menggunakan kitosan sebagai crosslinking agent. Berdasarkan hasil Scanning Electron Microscope (SEM),diketahui bahwa morfologi partikel TiO2 berbentuk spherical dengan ukuran nano (kurang dari 100 nm). Karakterisasi X-Ray Diffraction (XRD) menunjukkan adanya tiga tipe struktur kristal utama, yaitu (100), (101) dan (102) dengan fasa kristal yang terbentuk adalah anatase dan rutile. Pada karakterisasi menggunakan SEM terhadap serbuk dari TiO2 yang telah diaplikasikan ke permukaan kain kapas, terlihat adanya imobilisasi partikel nano TiO2 melalui ikatan hidrogen silang dengan kitosan pada kain kapas. Hasil analisa tersebut kemudian dikonfirmasi dengan FTIR (Fourier Transform Infra Red) yang hasilnya memperlihatkan puncak serapan pada bilangan gelombang 3495 cm-1, 2546 cm-1, dan 511 cm-1,  yang masing-masing diasumsikan sebagai adanya vibrasi gugus fungsi O-H, N-H dan Ti-O-Ti. Hasil SEM menunjukkan pula bahwa kristal nano yang terbentuk diantaranya adalah fasa rutile , yang berdasarkan literatur terbukti dapatberfungsi sebagai anti UV.


Author(s):  
Y. N. Hua ◽  
Z. R. Guo ◽  
L. H. An ◽  
Shailesh Redkar

Abstract In this paper, some low yield cases in Flat ROM device (0.45 and 0.6 µm) were investigated. To find killer defects and particle contamination, KLA, bitmap and emission microscopy techniques were used in fault isolation. Reactive ion etching (RIE) and chemical delayering, 155 Wright Etch, BN+ Etch and scanning electron microscope (SEM) were used for identification and inspection of defects. In addition, energy-dispersive X-ray microanalysis (EDX) was used to determine the composition of the particle or contamination. During failure analysis, seven kinds of killer defects and three killer particles were found in Flat ROM devices. The possible root causes, mechanisms and elimination solutions of these killer defects/particles were also discussed.


Sign in / Sign up

Export Citation Format

Share Document