scholarly journals Optimal Hot-Dipped Tinning Process Routine for the Fabrication of Solderable Sn Coatings on Circuit Lead Frames

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1191
Author(s):  
Ting Yin ◽  
Nan Xiang ◽  
Guangxin Wang ◽  
Baohong Tian ◽  
Wanting Sun ◽  
...  
Keyword(s):  
Copper Substrate ◽  
Electronic Industry ◽  
Different Types ◽  
Cu Substrates ◽  
Dipping Temperature ◽  
Modification Technique ◽  
Cost Efficient ◽  
Materials Used ◽  
Alkaline Cleaning ◽  
Dipping Time

Previous studies merely focus on the hot dipping properties of lead frame materials used in electronic industry. Yet, the environmentally friendly and cost-efficient traits of hot-dipped tinning process make it a possible promising surface modification technique compared with electroplating. As a result, the optimal hot-dipped tinning process routine is proposed in this paper. The hot-dipped tinning process of four different types of copper foils (C11000, C19400, C19210, and C70250), pretreatment parameters, mechanical properties of Cu substrates, thickness of IMC (intermetallic compound) layers and coatings, and microstructure of coatings were investigated to determine the copper substrate suitable for hot-dipped tinning and the optimized tinning procedures. The results indicate that a proper increase in alloying elements (e.g., Cu-Fe-P series alloys) towards Cu substrate leads to a decrease in hot dipping performance. The proper process routine is determined as alkaline cleaning→water scrubbing→accelerant solvent dipping→drying→hot-dipped tinning→cooling. The appropriate dipping temperature range is 260 to 280 °C, which assists to maintain acceptable micro hardness (i.e., maintaining at least 95% of the original hardness). The optimal dipping time should be set as 6–10 s. The proposed hot-dipped tinning process routine may present a guideline for the fabrication of tin coating in electronic industry.

scholarly journals Biopolymeric Materials Used as Nonviral Vectors: A Review

2021 ◽  
Vol 2 (1) ◽  
pp. 100-109
Author(s):  
Jailson de Araújo Santos ◽  
Daniel Barbosa Liarte ◽  
Alessandra Braga Ribeiro ◽  
Marcia dos Santos Rizzo ◽  
Marcília Pinheiro da Costa ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Web Of Science ◽  
Gene Transfection ◽  
Genetic Material ◽  
Nonviral Vectors ◽  
Cationic Polymers ◽  
Genetic Trait ◽  
Low Diversity ◽  
Different Types ◽  
Materials Used

Bacterial transformation and gene transfection can be understood as being the results of introducing specific genetic material into cells, resulting in gene expression, and adding a new genetic trait to the host cell. Many studies have been carried out to investigate different types of lipids and cationic polymers as promising nonviral vectors for DNA transfer. The present study aimed to carry out a systematic review on the use of biopolymeric materials as nonviral vectors. The methodology was carried out based on searches of scientific articles and applications for patents published or deposited from 2006 to 2020 in different databases for patents (EPO, USPTO, and INPI) and articles (Scopus, Web of Science, and Scielo). The results showed that there are some deposits of patents regarding the use of chitosan as a gene carrier. The 16 analyzed articles allowed us to infer that the use of biopolymers as nonviral vectors is limited due to the low diversity of biopolymers used for these purposes. It was also observed that the use of different materials as nonviral vectors is based on chemical structure modifications of the material, mainly by the addition of cationic groups. Thus, the use of biopolymers as nonviral vectors is still limited to only a few polysaccharide types, emphasizing the need for further studies involving the use of different biopolymers in processes of gene transfer.

Location Depending Textures of the Human Dental Enamel

2010 ◽  
Vol 160 ◽  
pp. 281-286 ◽  
Author(s):  
Lars Raue ◽  
Helmut Klein
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Dental Enamel ◽  
Polymeric Materials ◽  
Incisor Tooth ◽  
Worst Case ◽  
Dental Fillings ◽  
Anisotropic Mechanical Properties ◽  
Different Types ◽  
Materials Used

Dental enamel is the most highly mineralised and hardest biological tissue in human body [1]. Dental enamel is made of hydroxylapatite (HAP) - Ca5(PO4)3(OH), which is hexagonal (6/m). The lattice parameters are a = b = 0.9418 nm und c = 0.6875 nm [1]. Although HAP is a very hard mineral, it can be dissolved easily in a process which is known as enamel demineralization by lactic acid produced by bacteria. Also the direct consumption of acid (e.g. citric, lactic or phosphoric acid in soft drinks) can harm the dental enamel in a similar way. These processes can damage the dental enamel. It will be dissolved completely and a cavity occurs. The cavity must then be cleaned and filled. It exists a lot of dental fillings, like gold, amalgam, ceramics or polymeric materials. After filling other dangers can occur: The mechanical properties of the materials used to fill cavities can differ strongly from the ones of the dental enamel itself. In the worst case, the filling of a tooth can damage the enamel of the opposite tooth by chewing if the interaction of enamel and filling is not equivalent, so that the harder fillings can abrade the softer enamel of the healthy tooth at the opposite side. This could be avoided if the anisotropic mechanical properties of dental enamel would be known in detail, hence then another filling could be searched or fabricated as an equivalent opponent for the dental enamel with equal properties. To find such a material, one has to characterise the properties of dental enamel first in detail for the different types of teeth (incisor, canine, premolar and molar). This is here exemplary done for a human incisor tooth by texture analysis with the program MAUD from 2D synchrotron transmission images [2,3,4].

Impact of multi-dimensional vibration trajectories on quality and failure modes in ultrasonic bonding

2019 ◽  
Vol 2019 (1) ◽  
pp. 000509-000514
Author(s):  
Reinhard Schemmel ◽  
Florian Eacock ◽  
Collin Dymel ◽  
Tobias Hemsel ◽  
Matthias Hunstig ◽  
...  
Keyword(s):  
Cross Sections ◽  
Failure Modes ◽  
Copper Substrate ◽  
Industrial Process ◽  
Acoustic Microscopy ◽  
Ultrasonic Power ◽  
Bond Quality ◽  
Ultrasonic Bonding ◽  
Different Types ◽  
Electrical Connections

Abstract Ultrasonic joining is a common industrial process. To build electrical connections in the electronics industry, uni-axial and torsional ultrasonic vibration have been used to join different types of workpieces for decades. Many influencing factors like ultrasonic power, bond normal force, bond duration and frequency are known to have a high impact on bond quality and reliability. Multi-dimensional bonding has been investigated in the past to increase ultrasonic power and consequently bond strength. This contribution is focused on the comparison of circular, multi-frequency planar and uniaxial vibration trajectories used for ultrasonic bonding of copper pins on copper substrate. Bond quality was analyzed by shear tests, scanning acoustic microscopy and interface cross-sections.

scholarly journals Nano-Structured Optical Fibers Made of Glass-Ceramics, and Phase Separated and Metallic Particle-Containing Glasses

Fibers ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 105 ◽  
Author(s):  
Alexander Veber ◽  
Zhuorui Lu ◽  
Manuel Vermillac ◽  
Franck Pigeonneau ◽  
Wilfried Blanc ◽  
...  
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Metallic Nanoparticles ◽  
Glass Ceramics ◽  
Optical Quality ◽  
High Optical Quality ◽  
Characterization Methods ◽  
Different Types ◽  
Fabrication And Characterization ◽  
Materials Used

For years, scientists have been looking for different techniques to make glasses perfect: fully amorphous and ideally homogeneous. Meanwhile, recent advances in the development of particle-containing glasses (PCG), defined in this paper as glass-ceramics, glasses doped with metallic nanoparticles, and phase-separated glasses show that these “imperfect” glasses can result in better optical materials if particles of desired chemistry, size, and shape are present in the glass. It has been shown that PCGs can be used for the fabrication of nanostructured fibers—a novel class of media for fiber optics. These unique optical fibers are able to outperform their traditional glass counterparts in terms of available emission spectral range, quantum efficiency, non-linear properties, fabricated sensors sensitivity, and other parameters. Being rather special, nanostructured fibers require new, unconventional solutions on the materials used, fabrication, and characterization techniques, limiting the use of these novel materials. This work overviews practical aspects and progress in the fabrication and characterization methods of the particle-containing glasses with particular attention to nanostructured fibers made of these materials. A review of the recent achievements shows that current technologies allow producing high-optical quality PCG-fibers of different types, and the unique optical properties of these nanostructured fibers make them prospective for applications in lasers, optical communications, medicine, lighting, and other areas of science and industry.

scholarly journals INNOVATION OF THE TRADITIONAL SANDSTONE CRAFT PRODUCTS IN THE GLOBALIZATION ERA AT NORTH SINGAPADU VILLAGE GIANYAR

2017 ◽  
pp. 1
Author(s):  
I Ketut Muka Pendet ◽  
I Ketut Ardhana ◽  
I Nyoman Suarka ◽  
I Gede Arya Sugiartha
Keyword(s):  
Cultural Change ◽  
Formal Education ◽  
Local Identity ◽  
Way Of Life ◽  
Different Types ◽  
Aesthetic Style ◽  
New Ideas ◽  
Materials Used ◽  
Modern Technologies

Nowadays the process through which the sandstone craft products are produced at North Singapadu Village has changed. The appearance of different types of popular sandstone craft products reflecting the local identity produced by the young craftsmen at North Singapadu Village shows this. Such products are different from the traditional sandstone craft ones in terms of form and aesthetic style. Globalization, ideology and technology have basically led to the change. The sandstone industry has become highly innovative. This present study uses the qualitative and interpretative method and the theories used are the theory of acculturation, the theory of deconstruction, and the theory of postmodern aesthetics.              The conclusion of the present study is that the form and process of innovation initially resulted from new ideas and concepts and the craftsmen’s paradigm. The main things which have been responsible for changing the traditional way of life into the modern way of life are formal education, tourism and modern technologies. Those who are positively and negatively affected by globalization are not only the capital owners and craftsmen but the villagers and consumers as well. The sandstone craft products at North Singapadu Village contain the meaning of creativity, the economic meaning, the commodificative meaning and the meaning of cultural change. The finding of the study shows that the craftsmen at North Singapadu Village have ignored the traditional concepts, the technique of producing the products, and the materials used. However, the sandstone craft products at North Singapadu Village do not get extinct but remain to exist and both domestic and foreign consumers are interested in them.

Development of the New Generation Materials for the Soft Pipe Lining Rehabilitation

2005 ◽  
Author(s):  
Hsin Her Yu ◽  
Min-Hsun Cheng ◽  
Rong-Yuan Jou ◽  
Kuang-Chyi Lee ◽  
Chien-Chang Lin
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resins ◽  
Potable Water ◽  
Raw Materials ◽  
Trade Mark ◽  
Power Cables ◽  
Different Types ◽  
Materials Used ◽  
New Generation ◽  
Optimum Sample

With increasing global urbanization and industrialization, many more pipelines for gas, potable water, sewer, oil, and power cables have been installed underground, underwater, in buildings and in factories. Maintenance of such pipelines is crucial. However, it is often difficult and has become a growing problem these days. The PALTEM-HL (Trade mark and stands for Pipeline Automatic Lining SysTEM, Hose Lining Method), a pipeline relining system, was developed as an effective and inexpensive solution for this problem. In this project, we try to develop a new resins and the adhesives system to replace the raw materials used in the PALTEM-HL system. Anionic harder combined two different types of epoxy resins were investigated in this study. After curing, the mechanical properties and glass transition temperature of the mixture were examined and the optimum sample preparation prescription was also found. FTIR (Fourier Transform Infrared Spectroscopy) and DSC (Differential Scanning Calorimeter) were employed to monitor the curing process of the mixtures. The mechanical properties of the mixture were also measured by Instron and micro Vickers.

A Study on the Electrical Properties of ZnO Based Transparent TFTs

2006 ◽  
Vol 514-516 ◽  
pp. 68-72 ◽  
Author(s):  
Pedro Barquinha ◽  
Elvira Fortunato ◽  
Alexandra Gonçalves ◽  
Ana Pimentel ◽  
António Marques ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Electrical Characterization ◽  
Channel Mobility ◽  
Grain Sizes ◽  
Different Types ◽  
Effective Saturation ◽  
Materials Used ◽  
Silicon Based ◽  
Nanocrystalline Zinc Oxide ◽  
Output Conductance

The purpose of this work is to present in-depth electrical characterization on transparent TFTs, using zinc oxide produced at room temperature as the semiconductor material. Some of the studied aspects were the relation between the output conductance in the post-pinch-off regime and width-to-length ratios, the gate leakage current, the semiconductor/insulator interface traps density and its relation with threshold voltage. The main point of the analysis was focused on channel mobility. Values extracted using different methodologies, like effective, saturation and average mobility, are presented and discussed regarding their significance and validity. The evolution of the different types of mobility with the applied gate voltage was investigated and the obtained results are somehow in disagreement with the typical behavior found on classical silicon based MOSFETs, which is mainly attributed to the completely different structures of the semiconductor materials used in the two situations: while in MOSFETS we have monocrystalline silicon, our transparent TFTs use poly/nanocrystalline zinc oxide with grain sizes of about 10 nm.

Historical Persian Recipes for Paper Dyes

2016 ◽  
Vol 37 (1) ◽  
Author(s):  
Mandana Barkeshli
Keyword(s):  
Nineteenth Century ◽  
Historical Sources ◽  
Different Types ◽  
Application Techniques ◽  
Materials Used ◽  
Historical References

AbstractDuring the Taimurid (1370–1507 A.D.) and Safawid 1501–1736 A.D.) to Qajar periods (1785–1925 A.D.), Iranian masters introduced a number of paper dyes in order to prepare a suitable support for their calligraphies and paintings. This paper will discuss the different types of dyes and application techniques as described in Persian historical sources. Eighteen manuscripts from the thirteenth to the nineteenth century were selected and studied in detail; recipes were translated and categorized according to colour, materials and techniques in order to be able to draw comparisons. Studying these historical references not only adds a new dimension to the identification of materials used in manuscripts and miniature paintings of the period under study, but also can help to preserve the colours by providing a better understanding of their composition, manufacture and use.

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