scholarly journals Boehm Titration Revisited (Part I): Practical Aspects for Achieving a High Precision in Quantifying Oxygen-Containing Surface Groups on Carbon Materials

2018 ◽  
Vol 4 (2) ◽  
pp. 21 ◽  
Author(s):  
◽  
◽  
◽  
Keyword(s):  
High Precision ◽  
Carbon Materials ◽  
Surface Groups ◽  
Boehm Titration

On the Characterization of Chemical Surface Groups of Carbon Materials

2002 ◽  
Vol 248 (1) ◽  
pp. 116-122 ◽  
Author(s):  
M. Domingo-García ◽  
F.J. López Garzón ◽  
M.J. Pérez-Mendoza
Keyword(s):  
Carbon Materials ◽  
Surface Groups ◽  
Chemical Surface

scholarly journals Carbon materials obtained by carbonization of electrochemically gelled alginates and chitosan for supercapacitors

Tehnika ◽  
2020 ◽  
Vol 75 (6) ◽  
pp. 545-552
Author(s):  
Olivera Lužanin ◽  
Aleksandra Janošević-Ležaić ◽  
Nemanja Gavrilov
Keyword(s):  
Double Layer ◽  
Acidic Medium ◽  
Carbon Materials ◽  
Specific Capacity ◽  
Surface Groups ◽  
Dominant Form ◽  
Maximum Value ◽  
Double Layer Capacity ◽  
Capacitance Characteristics ◽  
Ph Dependent

The aim of this work is to investigate the capacitive characteristics of carbon-based materials obtained by carbonization of electrochemically synthesized gels based on alginate (CA-i, CA-3i, CA-3n), chitosan (CH-i), as well as their composites (CHA-i) using cyclic voltammetry at different polarization rates. The capacitance characteristics of the examined materials were tested in 6M KOH and 0.5M H2SO4, The specific capacities of the tested materials, in an acidic medium, at a polarization rate of 2 mV / s, decrease according to the following sequence: C-A-i> C-HA-i> C-A-3i> C-A-3n> C-H-i, where the maximum value of the specific capacity is 362 F / g. Also, based on the obtained results, a large decrease in capacity was observed, accompanied by an increase in the speed of polarization of the working electrode. The capacitance properties were successfully separated using the Trasatti and Dunn methods, and the results of both methods are largely consistent. It has been shown that the dominant form of energy storage through Faraday reactions, ie the share of pseudocapacitance, is large in all materials. The highest share of double-layer capacity in acidic medium was recorded in C-H-i, while in the base medium the largest share of double-layer capacity was present in material C-A-3n, due to the fact that electrochemical activity of surface groups (oxygen and / or nitrogen) is pH-dependent.

Automatic measurement of SAED patterns from asbestos minerals

1988 ◽  
Vol 46 ◽  
pp. 846-847
Author(s):  
J. C. Russ ◽  
T. Taguchi ◽  
P. M. Peters ◽  
E. Chatfield ◽  
J. C. Russ ◽  
...  
Keyword(s):  
Diffraction Pattern ◽  
High Precision ◽  
Diffraction Data ◽  
Automatic Measurement ◽  
Automatic Method ◽  
Important Method ◽  
X Ray ◽  
Integrated Intensity ◽  
Asbestiform Minerals ◽  
True Center

Conventional SAD patterns as obtained in the TEM present difficulties for identification of materials such as asbestiform minerals, although diffraction data is considered to be an important method for making this purpose. The preferred orientation of the fibers and the spotty patterns that are obtained do not readily lend themselves to measurement of the integrated intensity values for each d-spacing, and even the d-spacings may be hard to determine precisely because the true center location for the broken rings requires estimation. We have implemented an automatic method for diffraction pattern measurement to overcome these problems. It automatically locates the center of patterns with high precision, measures the radius of each ring of spots in the pattern, and integrates the density of spots in that ring. The resulting spectrum of intensity vs. radius is then used just as a conventional X-ray diffractometer scan would be, to locate peaks and produce a list of d,I values suitable for search/match comparison to known or expected phases.

On effects of non-systematic reflections on weak-beam images of partial dislocations

1991 ◽  
Vol 49 ◽  
pp. 688-689
Author(s):  
K. Z. Botros ◽  
S. S. Sheinin
Keyword(s):  
High Precision ◽  
Stacking Fault ◽  
Important Application ◽  
Stacking Fault Energy ◽  
Sharp Peak ◽  
Weak Beam ◽  
Partial Dislocations ◽  
Deviation Parameter ◽  
Beam Diffraction

The main features of weak beam images of dislocations were first described by Cockayne et al. using calculations of intensity profiles based on the kinematical and two beam dynamical theories. The feature of weak beam images which is of particular interest in this investigation is that intensity profiles exhibit a sharp peak located at a position very close to the position of the dislocation in the crystal. This property of weak beam images of dislocations has an important application in the determination of stacking fault energy of crystals. This can easily be done since the separation of the partial dislocations bounding a stacking fault ribbon can be measured with high precision, assuming of course that the weak beam relationship between the positions of the image and the dislocation is valid. In order to carry out measurements such as these in practice the specimen must be tilted to "good" weak beam diffraction conditions, which implies utilizing high values of the deviation parameter Sg.

Digital differential hysteresis iimage processing displays what the microscope acquires but the eye can't see

1995 ◽  
Vol 53 ◽  
pp. 642-643
Author(s):  
Klaus-Ruediger Peters
Keyword(s):  
Image Processing ◽  
Visual System ◽  
High Precision ◽  
Image Data ◽  
Processing Technology ◽  
Output Data ◽  
Contrast Resolution ◽  
Pixel Intensity ◽  
Data Reading ◽  
Hysteresis Properties

Differential hysteresis processing is a new image processing technology that provides a tool for the display of image data information at any level of differential contrast resolution. This includes the maximum contrast resolution of the acquisition system which may be 1,000-times higher than that of the visual system (16 bit versus 6 bit). All microscopes acquire high precision contrasts at a level of <0.01-25% of the acquisition range in 16-bit - 8-bit data, but these contrasts are mostly invisible or only partially visible even in conventionally enhanced images. The processing principle of the differential hysteresis tool is based on hysteresis properties of intensity variations within an image.Differential hysteresis image processing moves a cursor of selected intensity range (hysteresis range) along lines through the image data reading each successive pixel intensity. The midpoint of the cursor provides the output data. If the intensity value of the following pixel falls outside of the actual cursor endpoint values, then the cursor follows the data either with its top or with its bottom, but if the pixels' intensity value falls within the cursor range, then the cursor maintains its intensity value.

Three-dimensional distribution of ribulose-1, 5-bisphosphate carboxylase/oxygemase during the early development of proplastids in dark-grown Euglena cells transferred to an inorganic medium

1990 ◽  
Vol 48 (3) ◽  
pp. 906-907
Author(s):  
Tomoko Ehara ◽  
Shuji Sumida ◽  
Tetsuaki Osafune ◽  
Eiji Hase
Keyword(s):  
Cell Suspension ◽  
Euglena Gracilis ◽  
Carbon Materials ◽  
Three Dimensional ◽  
Peripheral Region ◽  
Plastid Development ◽  
Bisphosphate Carboxylase ◽  
Inorganic Medium ◽  
Ribulose 1 ◽  
Dimensional Distribution

As shown previously, Euglena cells grown in Hutner’s medium in the dark without agitation accumulate wax as well as paramylum, and contain proplastids showing no internal structure except for a single prothylakoid existing close to the envelope. When the cells are transferred to an inorganic medium containing ammonium salt and the cell suspension is aerated in the dark, the wax was oxidatively metabolized, providing carbon materials and energy 23 for some dark processes of plastid development. Under these conditions, pyrenoid-like structures (called “pro-pyrenoids”) are formed at the sites adjacent to the prolamel larbodies (PLB) localized in the peripheral region of the proplastid. The single prothylakoid becomes paired with a newly formed prothylakoid, and a part of the paired prothylakoids is extended, with foldings, in to the “propyrenoid”. In this study, we observed a concentration of RuBisCO in the “propyrenoid” of Euglena gracilis strain Z using immunoelectron microscopy.

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