Critical issues in the characterization of polymers for medical application

The discovery of graphene and its analog, such as MoS2, has boosted research. The thermal transport in 2D materials gains much of the interest, especially when graphene has high thermal conductivity. However, the thermal properties of 2D materials obtained from experiments have large discrepancies. For example, the thermal conductivity of single layer suspended graphene obtained by experiments spans over a large range: 1100–5000 W/m·K. Apart from the different graphene quality in experiments, the thermal characterization methods play an important role in the observed large deviation of experimental data. Here we provide a critical review of the widely used thermal characterization techniques: the optothermal Raman technique and the micro-bridge method. The critical issues in the two methods are carefully revised and discussed in great depth. Furthermore, improvements in Raman-based techniques to investigate the energy transport in 2D materials are discussed.

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Preliminary morphological and anatomical study of Orthosiphon stamineus

Indian Journal of Pharmaceutical and Biological Research ◽

10.30750/ijpbr.1.4.1 ◽

2013 ◽

Vol 1 (04) ◽

pp. 01-06 ◽

Cited By ~ 1

Author(s):

Manaf Almatar ◽

Zaidah Rahmat ◽

Faezah Mohd Salleh

Keyword(s):

Medicinal Plant ◽

Cross Sections ◽

Morphological Study ◽

Developmental Stages ◽

Anatomical Study ◽

Medical Application ◽

Orthosiphon Stamineus ◽

Phenolics Compounds ◽

Wide Usage

This study focuses on the characterization of morphological and anatomical traits of Orthosiphon stamineus which belongs to the Lamiaceae family. Orthosiphon stamineus, better known as “Misai Kucing” or “cats whiskers” by the locals, contained active phenolics compounds such as flavanoids. Despite its wide usage as a medicinal plant, information regarding Orthosiphon stamineus specific developmental stages is relatively scarce. Furthermore, to date, no anatomical data of this plant is available. Therefore, this study aims to systematically identify the developmental stages and its anatomy which may provide more insight to its medical application. The result showed some distinct morphological and anatomical characteristics. In the morphological study, it was observed that Orthosiphon stamineus is a herbal shrub with well-developed creeping rootstock. The leaves are simple, green, and arranged in opposite pairs. The stem is approximately 28 cm in height at the stage (12 days). The flowers have long wispy stamens shaped with pale purple color. In anatomical study, the cross sections of the stem for tow stage (32) and (62) days of this plant were examined. All the detailed systematic study of this plant has not worked earlier.

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A Novel Approach to the Measurement and Characterization of Losses due to Surface Roughness in High Speed Transmission Lines

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/cicmt-2011-wp23 ◽

2011 ◽

Vol 2011 (CICMT) ◽

pp. 000241-000245

Author(s):

Femi Akinwale ◽

A. Ege Engin

Keyword(s):

Surface Roughness ◽

Transmission Lines ◽

High Speed ◽

Data Transfer ◽

Signal Propagation ◽

High Frequencies ◽

Novel Approach ◽

Critical Issues ◽

5 Ghz

An accurate measurement technique is required to fully characterize the losses observed at high frequencies in transmission lines. Evaluation of losses seen at high frequencies is necessary to meet the high-speed data transfer rates that future applications will demand. Conductor properties and losses are two critical issues in signal path characterization. The nature of conductor losses is not well understood at high speeds. Classical models used for predicting the effects of surface roughness on signal propagation are known to breakdown around 5 GHz. Novel methods are sought to quantify the effects beyond 5 GHz. In this paper, a simple methodology to extract conductor loss is derived and validated based on a stripline configuration of two different widths. The proposed methodology is applicable to surface roughness loss characterization of both organic and ceramic packaging materials.

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Synthesis and Characterization of Doped and Undoped Nano-Columnar DLC Coating

Jurnal Teknologi ◽

10.11113/jt.v62.1176 ◽

2013 ◽

Vol 62 (1) ◽

Author(s):

Jin Hoe Foo

Keyword(s):

Amorphous Carbon ◽

Mechanical Response ◽

Medical Application ◽

Columnar Structure ◽

High Wear Resistance ◽

Nano Structure ◽

Force Microscopy ◽

Dlc Coating ◽

Atomic Force

Amorphous carbon (a-C:H/a-C) or Diamond-like carbon (DLC), has a very high potential diverse engineering and medical application for high wear resistance and tribological performance. Naturally grown columnar DLC films is chemically modified by post-treatment via electron beam irradiation (EB-irradiation), through precise observation and characterization by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and Raman spectroscopy. This nano-columnar a-C:H film has a unique nano-structure and mechanical properties. This nano-columnar structure is composed of graphitic inter-columnar network with amorphous carbon columns. Metallic doping into the inter-columns reflects positively on mechanical response by chemical modification with physical hardening.

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Photo-Assisted Corona-Charge Characterization of Wide Bandgap Interfaces with Deep Traps Invisible in Standard C-V

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1004.601 ◽

2020 ◽

Vol 1004 ◽

pp. 601-607

Author(s):

Alexandre Savtchouk ◽

Marshall Wilson ◽

John D’Amico ◽

Carlos Almeida ◽

Andrew Hoff ◽

...

Keyword(s):

Wide Bandgap ◽

Device Fabrication ◽

Effective Control ◽

Time Saving ◽

Non Invasive ◽

Deep Traps ◽

Critical Issues ◽

Photo Ionization ◽

Corona Charge

Wide bandgap semiconductor technology has been generating a great deal of attention due to its fundamental advantages in high power electronics. Understanding and effective control of interfacial properties belong to a group of critical issues requiring progress. In this work, we report progress in wide bandgap interface characterization, achieved using photo-ionization of deep traps under a non-equilibrium condition created by corona-charge bias in deep depletion. This characterization capability is demonstrated on oxidized n-type epitaxial SiC with deep interfacial traps invisible in standard C-V. These traps, initially present at high density, are shown to be reduced by half after a wet anneal. The photo-ionization technique is incorporated in commercially available non-contact C-V (CnCV) metrology [1,2] providing a non-invasive, cost and time saving metrology that benefits development research as well as device fabrication.

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Shape Memory Alloys and Polymers for MEMS/NEMS Applications: Review on Recent Findings and Challenges in Design, Preparation, and Characterization

Metals ◽

10.3390/met11030415 ◽

2021 ◽

Vol 11 (3) ◽

pp. 415

Author(s):

Ivo Stachiv ◽

Eduardo Alarcon ◽

Miroslav Lamac

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

High Energy ◽

High Energy Density ◽

Future Research ◽

Multilayered Structures ◽

Critical Issues ◽

Future Research Directions ◽

Tunable Metamaterial

Rapid progress in material science and nanotechnology has led to the development of the shape memory alloys (SMA) and the shape memory polymers (SMP) based functional multilayered structures that, due to their capability to achieve the properties not feasible by most natural materials, have attracted a significant attention from the scientific community. These shape memory materials can sustain large deformations, which can be recovered once the appropriate value of an external stimulus is applied. Moreover, the SMAs and SMPs can be reprogrammed to meet several desired functional properties. As a result, SMAs and SMPs multilayered structures benefit from the unprecedented physical and material properties such as the shape memory effect, superelasticity, large displacement actuation, changeable mechanical properties, and the high energy density. They hold promises in the design of advanced functional micro- and nano-electro-mechanical systems (MEMS/NEMS). In this review, we discuss the recent understanding and progress in the fields of the SMAs and SMPs. Particular attention will be given to the existing challenges, critical issues, limitations, and achievements in the preparation and characterization of the SMPs and NiTi-based SMAs thin films, and their heterostructures for MEMS/NEMS applications including both experimental and computational approaches. Examples of the recent MEMS/NEMS devices utilizing the unique properties of SMAs and SMPs such as micropumps, microsensors or tunable metamaterial resonators are highlighted. In addition, we also introduce the prospective future research directions in the fields of SMAs and SMPs for the nanotechnology applications.

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