Crystalline Structure Determination of Anisotropic Dimethyl Terephthalate Crystallites by Micro-Raman Spectroscopy

2000 ◽  
Vol 15 (6) ◽  
pp. 1397-1403 ◽  
Author(s):  
R. Rodrĺguez ◽  
S. Pacheco ◽  
S. Vargas ◽  
S. Jiménez ◽  
V. M. Castaño
Keyword(s):  
Molecular Orientation ◽  
Symmetry Axis ◽  
Laser Light ◽  
Incident Laser ◽  
Crystal Axis ◽  
Micro Raman Spectroscopy ◽  
Dimethyl Terephthalate ◽  
Novel Approach ◽  
Tilting Angle

A novel approach to determine the molecular orientation of dimethyl terephthalate molecules with respect to the direction of the crystal axis is reported. This determination was achieved by changing the crystal orientation with respect to the incident laser light of a micro-Raman spectrometer. Raman spectra were obtained at different incidence angles of the laser beam with respect to the crystal symmetry axis. The intensities of some specific bands were analyzed as a function of the tilting angle. With this information the molecular orientation with respect to the crystal axis was determined making use of a simple mechanical model.

The Use of TMAH to Etch Silicon and Expose Metal Bridging Failures

2000 ◽  
Author(s):  
Mark Morris ◽  
James Mohr ◽  
Esteban Ortiz ◽  
Steven Englebretson
Keyword(s):  
Failure Mechanism ◽  
Schottky Diodes ◽  
Tetramethylammonium Hydroxide ◽  
Novel Approach ◽  
Failure Location ◽  
Metal Etching ◽  
Plastic Mold

Abstract Determination of metal bridging failures on plastic encapsulated devices is difficult due to the metal etching effects that occur while removing many of the plastic mold compounds. Typically, the acids used to remove the encapsulation are corrosive to the metals that are found within the device. Thus, decapsulation can result in removal of the failure mechanism. Mechanical techniques are often not successful due to damage that results in destruction of the die and failure mechanism. This paper discusses a novel approach to these types of failures using a silicon etch and a backside evaluation. The desirable characteristics of the technique would be to remove the silicon and leave typical device metals unaffected. It would also be preferable that the device passivation and oxides not be etched so that the failure location is not disturbed. The use of Tetramethylammonium Hydroxide (TMAH), was found to fit these prerequisites. The technique was tested on clip attached Schottky diodes that exhibited resistive shorting. The use of the TMAH technique was successful at exposing thin solder bridges that extruded over the edge of the die resulting in failure.

Preservation for diverse users: digital preservation and the “Designated Community” at the Ontario Jewish Archives

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nathan Moles
Keyword(s):  
Digital Preservation ◽  
Reference Points ◽  
Digital Information ◽  
User Group ◽  
Content Type ◽  
Open Archival Information System ◽  
Novel Approach ◽  
Core Components ◽  
Unique Approach

PurposeConventional approaches to digital preservation posit that archives should define a Designated Community, or future user group, for whom they preserve digital information. Archivists can then use their knowledge of these users as a reference to help them deliver digital information that is intelligible and usable. However, this approach is challenging for archives with mandates to serve wide and diverse audiences; these archives risk undermining their efforts by focusing on the interests of a narrow user group.Design/methodology/approachA unique approach to this challenge was developed in the context of a project to build a digital preservation program at the Ontario Jewish Archives (OJA). It draws from previous research on this topic and is based on a combination of practical and theoretical considerations.FindingsThe approach described here replaces the reference of a Designated Community with three core components: a re-articulation of the Open Archival Information System (OAIS) mandatory responsibilities; the identification of three distinct tiers of access for digital records; and the implementation of an access portal that allows digital records to be accessed and rendered online. Together with supplemental shifts in reference points, they provide an alternative to the concept of a Designated Community in the determination of preservation requirements, the identification of significant properties, the creation of Representation Information and in the evaluation of success.Originality/valueThis article contributes a novel approach to the ongoing conversation about the Designated Community in digital preservation, its application and its limitations in an archival context.

scholarly journals Fabrication of Carbohydrate Chips Based on Polydopamine for Real-Time Determination of Carbohydrate–Lectin Interactions by QCM Biosensor

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1275 ◽  
Author(s):  
Kun Shang ◽  
Siyu Song ◽  
Yaping Cheng ◽  
Lili Guo ◽  
Yuxin Pei ◽  
...  
Keyword(s):  
Real Time ◽  
Con A ◽  
Quartz Crystals ◽  
Ulex Europaeus ◽  
Novel Approach ◽  
Ulex Europaeus Agglutinin I ◽  
Flow Through ◽  
Time Determination ◽  
Kinetics Of

A novel approach for preparing carbohydrate chips based on polydopamine (PDA) surface to study carbohydrate–lectin interactions by quartz crystal microbalance (QCM) biosensor instrument has been developed. The amino-carbohydrates were immobilized on PDA-coated quartz crystals via Schiff base reaction and/or Michael addition reaction. The resulting carbohydrate-chips were applied to QCM biosensor instrument with flow-through system for real-time detection of lectin–carbohydrate interactions. A series of plant lectins, including wheat germ agglutinin (WGA), concanavalin A (Con A), Ulex europaeus agglutinin I (UEA-I), soybean agglutinin (SBA), and peanut agglutinin (PNA), were evaluated for the binding to different kinds of carbohydrate chips. Clearly, the results show that the predicted lectin selectively binds to the carbohydrates, which demonstrates the applicability of the approach. Furthermore, the kinetics of the interactions between Con A and mannose, WGA and N-Acetylglucosamine were studied, respectively. This study provides an efficient approach to preparing carbohydrate chips based on PDA for the lectin–carbohydrate interactions study.

Laser fluorescence determination of lead in geological samples when vaporized by pulsed laser light

1992 ◽  
Vol 56 (3) ◽  
pp. 235-238 ◽  
Author(s):  
O. N. Ezhov ◽  
B. R. Kano ◽  
S. V. Oshemkov ◽  
A. A. Petrov
Keyword(s):  
Laser Light ◽  
Pulsed Laser ◽  
Laser Fluorescence ◽  
Geological Samples ◽  
Fluorescence Determination
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