Chemistry Commons^™

Large Area Projection Sintering Of Semicrystalline Polymers And Part Analysis Of The Printed Specimens, Taranjot Kaur

USF Tampa Graduate Theses and Dissertations

As the requirements posed to products have increased in recent years. The trend towards individualized serial products steps up the need for respective manufacturing techniques to be more and more flexible. Conventional techniques of serial production, such as injection molding, are unable to fully meet the requirements of this trend. Additive manufacturing techniques generate components directly from a CAD data set while requiring no specific mold, producing minimal waste, and reaching satisfactory geometric accuracy. This is how, as opposed to conventional techniques, they comply with these increased demands to processing technology. Over the last two decades, the research community has …

Synthesis And Catalytic Behaviors Of Sub-10nm Platinum Group Metal Nanocatalysts, Zixin Wang

Theses and Dissertations

Nanoparticles of platinum group elements(Pd, Pt, Rh, Ir, Ru and Os) exhibit intriguing catalytic behaviors that are sensitively dependent upon their particle dimensions, chemical compositions, and surface structures. Platinum group elementbased nanomaterials have been widely utilized for catalyzing a series of important chemical reactions, producing over 90% of chemicals and fuels and accounting for 35% of the world's GDP globally. Reducing the overall particle sizes of the catalysts to the sub-10 nm size regime not only effectively mitigates the cost issues associated with the noble metal-based materials, but also remarkably modifies the surface atomic coordinations and the electronic band energies, …

Small Molecule Activation By Dirhenium Carbonyl Complexes, Meenal Kaushal

Theses and Dissertations

The background of small molecule activation is discussed in Chapter 1. Carbon-hydrogen (C-H) bond activation and carbon-carbon (C-C) bond formation using transition metal complexes are explained using examples from the literature. It also includes the previous work done by Dr. Adams’ lab on C-H bond activation and zwitterions in metal carbonyl complexes.

The reaction of Re₂(CO)₈(µ-C₆H₅)(µ-H) with vinyl acetate yielding three new products has been discussed in Chapter 2. One of the products Re₃(CO)₁₃(µ-η² -C₂H₃), 2.3 further reacts with I₂ resulting in …

Mechanisms And Impact Of Hypoxia Regulated Inhibins In Cancer, Ben Allen Horst

Theses and Dissertations

Inhibins are heterodimeric ligands within the TGFβ superfamily, comprised of an α-subunit (INHA) and a β-subunit (either INHBA or INHBB) with emergent roles in cancer. Inhibins are biomarkers of disease burden and prognosis in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Previously, we found inhibin promotes angiogenesis in ovarian cancer however no mechanism of regulation for inhibin expression in cancer has been established. Hypoxia, a driver of tumor growth and metastasis, regulates angiogenic pathways that are targets for vessel normalization and ovarian cancer management. …

Evaluation Of The Energetic Factors In Crystalline Pharmaceuticals Using Solid-State Density Functional Theory And Low-Frequency Vibrational Spectroscopy, Margaret P. Davis

Dissertations - ALL

Due to the importance of maintaining stable and effective pharmaceutical solid doses, it is critical to study the variety of solid forms that active pharmaceutical ingredients can adopt including polymorphs, hydrates, and cocrystals. In this work, low-frequency vibrational spectroscopies and rigorous quantum mechanical simulations are combined to provide a new technique for characterizing and investigating pharmaceutically relevant polymorphs, hydrates, and cocrystals as well as a series of model cocrystals. Low-frequency spectra in the sub-200 cm-1 range provide not only unique and characteristic spectra for all of the systems explored here but, along with X-ray structural parameters, they offer a way …

Materials Discovery By Flux Crystal Growth: Synthesis, Structure Determination, Magnetic, And Optical Properties Of Complex Oxides, Oxychlorides, And Oxyfluorides, Darren Andrew Carone

Theses and Dissertations

Exploratory crystal growth has proven to be a successful technique in the synthesis of new compounds with desired properties. This method is very versatile and has various iterations, but results described herein were obtained through flux growth at high temperatures utilizing mixed alkali halide salts. The tunability of these reactions with respect to reactant ratios, reaction temperature, heating/cooling rates, metal precursors, and choice of flux allow for the exploration of phase spaces between a combination of elements and observation of significantly different products and/or structure types from minor tweaks.

Most of the research presented in this dissertation describes results that …

Crystal Growth Of Inorganic Halides And Oxide-Halides For Scintillation Applications And Radiation Detection, Gyanendra B. Ayer

Theses and Dissertations

Scintillators, materials which emit light when struck by high energy X-rays and y- rays, are extensively used in various fields including medical imaging, computed tomography, high-energy physics, and more recently in homeland security for the prevention of nuclear and radiological terrorism. While comparing with the traditional scintillators, which have long-term instability, high synthetic cost, toxicity, and hygroscopicity issues, metal halides have been reported to exhibit effective excitonic radioluminescence and greatly contribute in the field of scintillating applications and radiation detection. Currently, the mixed-anion oxide-fluorides have emerged as a prospective new class of scintillators, in which the mixed oxide-fluoride environment …

Novel Synthetic Strategies Toward Polyolefin-Grafted Nanoparticles, Richard Tran Ly

Theses and Dissertations

Surface functionalization of nanoparticles has proven to be a powerful and versatile strategy in the development of various materials with advanced properties. Polymer brush composition can range from complex copolymers to more simplistic polyolefin, and by functionalizing nanoparticle surfaces, mobility of distinct particles can then be tuned and, therefore, control over dispersion in a polymer matrix can be achieved. Presented in this dissertation are new synthetic strategies for the preparation of polymer nanocomposites.

The first chapter covers a novel synthetic strategy for ethylene/propylene-like copolymers grafted to silica nanoparticles. This approach utilizes Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization to promote living …

Uv- And Visible-Light Photopatterning Of Molecular Gradients Using The Thiol–Yne Click Reaction, Mark Mitmoen, Ofer Kedem

Chemistry Faculty Research and Publications

The rational design of chemical coatings is used to control surface interactions with small molecules, biomolecules, nanoparticles, and liquids as well as optical and other properties. Specifically, micropatterned surface coatings have been used in a wide variety of applications, including biosensing, cell growth assays, multiplexed biomolecule interaction arrays, and responsive surfaces. Here, a maskless photopatterning process is studied, using the photocatalyzed thiol–yne “click” reaction to create both binary and gradient patterns on thiolated surfaces. Nearly defect-free patterns are produced by first coating glass surfaces with mercaptopropylsilatrane, a silanizing agent that forms smoother self-assembled monolayers than the commonly used 3-mercaptopropyltrimethoxysilane. Photopatterning …

Method Of Hybrid Control Based Of Dynamic Objects Of Neuro-Fuzzy Inference, Noilakhon Yakubova

Karakalpak Scientific Journal

The Results of interaction of the work is development of a method of control that allows simplifying, automating and unifying the process of design of the hybrid systems which are a basis of modern automation. To achieve a definite purpose, a method of control of a technical object based on the construction of an adaptive system of neuro-fuzzy inference is developed. The objects of the system of neuro-fuzzy inference are the classical and neuro-fuzzy models of control. Information exchange between models is provided by means of the developed hybrid control system. The result of the interaction of the two models …

Application Of A Synergetic Approach To The Problem Of Synthesizing An Intelligent Control System For Chemical Reactors, Komil Usmanov

Karakalpak Scientific Journal

The article deals with the synthesis of effective algorithms for controlling a chemical reactor and developed a intelligent synergistic controller for a class of indefinite nonlinear dynamic systems. A synergetic control scheme is proposed for solving the control problem for nonlinear systems. Non-linear systems with configurations and parameters that change over time require a completely non-linear model and adaptive control scheme for a practical operating environment. The synthesis of control laws is performed by the method of analytical design of aggregated controllers (ADAR).

Development Of The Implementation Of Iot Monitoring System Based On Node-Red Technology, Anvar Kabulov, Inomjon Yarashov, Salamat Mirzataev

Karakalpak Scientific Journal

This article describes how to design and implement a process for storing environmental information in a database using the Internet of Things. The problems that need to be solved with the help of this IoT system are the growing demand for forecasts in the world, the demand of the world market for a new sustainable method of implementing the digitization environment through the Internet of Things. The design was implemented using Arduino, Node-Red and sensors, selected when choosing a component based on the required parameters and sent to the database for monitoring and processing. A study of previous work and …

Theoretical Features Of Foreign Systems Of Preschool Education, Ayjamal Bazarbaeva

Karakalpak Scientific Journal

This article analyzes the features of preschool education systems in foreign countries. The positive experience and features of some systems are highlighted. Comparison of domestic and foreign systems of preschool education is carried out.

Mechanism Of Sila- And Germafluorenes For Biological Applications, Shelby Jarrett

Dissertations

2,7-disubstituted silafluorenes and germafluorenes, originally designed for OLED applications, are a class of fluorescent dyes that have gained recent interest as probes for bioimaging and as biosensors to monitor cellular dynamics and interactions. Desirable biological probes absorb in the visible region, have high extinction coefficients, high quantum yield and excellent photostability. Here, their spectral properties are investigated under aqueous conditions for relevant biological applications. These molecules display intense blue fluorescence in the solid state and in solution, have high extinction coefficients, and exhibit appreciable solubility in aqueous solution. To better understand potential applications, the mechanism of fluorescence was investigated. It …

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

Carbon Monoxide Oxidation On Model Planar Titania Supported Platinum Nanoparticles Catalyst, Jovine Emmanuel, Brian Hayden

Tanzania Journal of Science

A high-throughput (parallel) thermographic screening methodology was developed to enable the measurements of the particle size and support influence on heterogeneous catalysts. A high throughput screening chip has been used to establish the catalytic activity of titania supported platinum nanoparticles catalyst for CO oxidation reaction. The catalytic activity of Pt nanoparticles between 1.3 to 7.8 nm has been investigated for CO conversion at a pressure of 0.11 and 1.1 mbar with O2:CO ratio of 1:1 at 80 °C and 0.6, 1.1 and 2.4 mbar at O2:CO ratio of 1:1 at 240 °C. At these experimental conditions, there was an increase …

Co-Microencapsulation Of Ruellia Tuberosa L. And Cosmos Caudatus K. Extracts For Pharmaceutical Applications, Choirin Annisa, Sasangka Prasetyawan, Anna Safitri

Makara Journal of Science

This study aims to co-microencapsulate the Ruellia tuberosa L. and Cosmos caudatus K. extracts, with chitosan–sodium tripolyphosphate (Na-TPP) as coating material. α-Amylase inhibition and antioxidant assays were conducted to determine the potential of microcapsules used as antidiabetic agents. The microcapsules were manufactured under the influences of pH, Na-TPP concentration, and stirring time. The optimum microencapsulation conditions were selected based on the highest encapsulation efficiency. The optimum microencapsulation conditions were a pH of 4, Na-TPP concentration of 0.15% (w/v), and stirring time of 60 min. The microcapsules exhibited an IC₅₀ (inhibitory concentration) value of 223.64 ± 0.81 µg/mL and an …

Preparation Of Zn/Al-Chitosan Composite For The Selective Adsorption Of Methylene Blue Dye In Water, Risfidian Mohadi, Patimah Mega Syah Bahar Nur Siregar, Neza Rahayu Palapa, Aldes Lesbani

Makara Journal of Science

Layered double hydroxide (LDHs) are widely used adsorbents for methylene blue removal. However, LDHs have a perishable structure that cannot be used repeatedly. Modifying LDHs with chitosan produces a strong material with a large surface area for methylene blue adsorption. Adsorption conditions were optimized by determining the adsorption isotherms and the adsorbent regeneration process. Results showed that the adsorption process was balanced in 90 min with maximum adsorption capacities of 86.207 mg/g, 35.336 mg/g, and 98.039 mg/g for Zn/Al, chitosan, and Zn/Al-chitosan, respectively. The adsorption in this study followed the Freundlich isotherm model. Regeneration analysis of the adsorbent showed that …

Characterization Of Clay And Granite Dust Blends As Novel Materials For Energy Storage And Diffuser In Constructing Flat-Plate Solar Collector, Tajudeen Kolawole Ajiboye, Mustapha Olawale Fabiyi, Ndagi Mustapha, Sulaiman Abdulkareem

Tanzania Journal of Science

Sun is the main source of solar energy, and the energy it releases to the Earth’s surface in one hour is more than what the whole planet consumes in a year. This present work is about characterizing novel material that can be used as energy storage and diffuser in constructing flat plate solar collector. Materials used are clay and granite dust obtained from Okelele and Kulende Quarry sites, both in Ilorin, Kwara State, Nigeria. The materials were sun-dried; the clay crushed before the two materials were sieved into different particle sizes. They were thereafter blended into different ratios and then …

New Simple And Robust Method For Determination Of Polarity Of Deep Eutectic Solvents (Dess) By Means Of Contact Angle Measurement, Łukasz Cichocki, Dorota Warmińska, Justyna Łuczak, Grzegorz Boczkaj, Andrzej Przyjazny

Natural Sciences Publications

The paper presents a new method for evaluating the polarity and hydrophobicity of deep eutectic solvents (DESs) based on the measurement of the DES contact angle on glass. DESs consisting of benzoic acid derivatives and quaternary ammonium chlorides–tetrabutylammonium chloride (TBAC) and benzyldimethylhexadecylammonium chloride (16-BAC)—in selected molar ratios were chosen for the study. To investigate the DESs polarity, an optical goniometer and an ET(30)" role="presentation" style="box-sizing: border-box; max-height: none; display: inline; line-height: normal; font-size: 13.2px; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; color: rgb(34, 34, 34); font-family: Arial, …

Introduction Of Development And Application Technology Of Organic Additives For Acid Copper Electroplating, Hao-Bin Zou, Chao-Li Tan, Wei Xiong, Dao-Lin Xi, Bin-Yun Liu

Journal of Electrochemistry

Acid copper electroplating is one of the key technologies in buildup multilayer PCB (BUM-PCB) manufacture process and the most important technique to achieve electrical interconnection between any layer and high-density interconnection in a substrate. This article introduces the research focus of organic additives used in acid copper electroplating, and developing different kinds of micro-via filling copper electroplating technique applied in various scenarios, and some other technical problems from applications. First of all, according to the chronopotentiometric (CP) experiment results, the levelers with different polymeric molecular structures exhibited various responses of cupric deposition potential along with their increased concentrations, which is …

Study On The Effect Of Additives In The Electrodeposition Of Sn-Ag-Cu Ternary Alloy Solder, Hua Miao, Ming-Rui Li, Wen-Zhong Zou, Guo-Yun Zhou, Shou-Xu Wang, Xiao-Jing Ye, Kai Zhu

Journal of Electrochemistry

Sn-Ag-Cu ternary alloy is the most ideal substitute for Sn-Pb alloy at present, and can be prepared by electrodeposition with high production efficiency, simple equipment, easy maintenance and excellent coating performance. The coordination system of the electroplating solution was investigated through the Hull cell experiment. The type of brighteners used in the plating solution and the ratio of the two brighteners were determined through the microscopic morphologic characterization, electrochemical corrosion test and cathodic polarization curve test. In addition, the dispersant and stabilizer were studied by observing the microscopic morphology and measuring the concentration change of Sn²⁺ ions in the …

Application Of Numerical Simulation Method In Periodic Pulse Reverse Electroplating Through Hole, Yuan-Hang Zhang, Mao-Zhong An, Pei-Xia Yang, Jin-Qiu Zhang

Journal of Electrochemistry

The upgrade of the fifth generation (5G) communication technology increases the number of communication backplane layers and the aspect ratio of through holes on the board, making it more difficult to use traditional direct current deposition for interconnection. Direct current electrodeposition is more prone to uneven coating in the hole, resulting in poor contact between the coating and components, and open circuit. This has a serious impact on the stability of printed circuit board. The periodic pulse reverse plating method can significantly improve the uniformity of high aspect ratio through-hole plating and improve the production quality of through-hole plating through …

Optimization Of Pulse Plating Additives And Plating Parameters For High Aspect Ratio Through Holes, Kai Yang, Ji-Da Chen, Shi-Jin Chen, Wei-Lian Xu, Mao-Gui Guo, Jin-Chao Liao, Zeng-Kun Wu

Journal of Electrochemistry

As an important component in electronic products, printed circuit board (PCB) plays a supporting and interconnecting role for the electronic components in it. With the development of communication technology, electronic products are developing in the direction of “thin, light and small”, and high density interconnection (HDI) comes into being. Due to the high-density interconnection characteristics of HDI boards, the thickness of the board is increasing. At the same time, in order to reserve space for the laying of fine lines on the subsequent board surface, the diameter of the through holes on the board is also decreasing, so the depth-diameter …

An Investigation On The Interface Corrosion Behaviors Of Cobalt Interconnects In Chemical Mechanical Polishing Slurry, Kai-Xuan Qin, Peng-Fei Chang, Yu-Lin Huang, Ming Li, Tao Hang

Journal of Electrochemistry

Cobalt is widely regarded as the most promising interconnect material for 10 nm node and beyond. The development of a chemical mechanical planarization (CMP) slurry suitable for cobalt interconnect is a critical component for the application of cobalt interconnect. During CMP process of the interconnect layer, the achievement of high-quality surface after planarization is greatly challenged by the metal corrosion in CMP slurry. In this contribution, the corrosion behavior of cobalt in a slurry with potassium persulfate (KPS) as an oxidizer, glycine as a complexing agent, and benzotriazole (BTA) as an inhibitor was investigated. Static erosion rates (SER) of cobalt …

Research Progresses Of Cobalt Interconnect And Superfilling By Electroplating In Chips, Li-Jun Wei, Zi-Han Zhou, Yun-Wen Wu, Ming Li, Su Wang

Journal of Electrochemistry

Copper interconnect using dual damascene technology has always been the main means for metallization in the back end of line process. However, with the size effect becoming more and more obvious due to feature size reduction, copper interconnect can no longer meet the demand for high circuit speed in Post-Moore era. Following copper interconnection, cobalt interconnection in chips attracts much attention as an interconnect technology by the next generation, which has been introduced in 7 nm node of integrated circuit manufacturing and below. The electron mean free path of cobalt (~10 nm) is much shorter than copper’s (39 nm), thus …

Electrochemical Sers Study Of Benzotriazole And 3-Mercapto-1-Propanesulfonate In Acidic Solution On Copper Electrode, Yin-Fei Shen, Yan-Li Chen, Sheng-Xu Wang, Ye Zhu, Wen-Chang Wang, Min-Xian Wu, Zhi-Dong Chen

Journal of Electrochemistry

Since the development of acid copper plating technology, the role of additives is indispensable. In addition to the main salt copper sulfate and supporting electrolyte sulfuric acid, suppressors, accelerators, levelers and chlorine ions (Cl^-) are also required to be added into the plating solution. Appropriate additive system can have a significant impact on the coating or the plating solution, which can help improve the quality of the coating and increase the brightness of the coating. Through electrochemical measurement, vibrational spectroscopy, scanning probe microscopy, molecular dynamics simulation and other methods, researches have a deeper understanding in the adsorption configuration …

Development Status Of Copper Electroplating Filling Technology In Through Glass Via For 3d Interconnections, Zhi-Jing Ji, Hui-Qin Ling, Pei-Lin Wu, Rui-Yi Yu, Da-Quan Yu, Ming Li

Journal of Electrochemistry

With the slow development of Moore's Law, the high density and miniaturization of microelectronic devices put forward higher requirements for advanced packaging technology. As a key technology in 2.5D/3D packaging, interposer technology has been extensively studied. According to different interposer materials, it is mainly divided into organic interposer, silicon interposer and glass interposer. Compared with the through silicon via (TSV) interconnection, the through glass via (TGV) interposer has received extensive attention in the 2.5D/3D advanced packaging field for its advantages of excellent high-frequency electrical characteristics, simple process, low cost, and adjustable coefficient of thermal expansion (CTE). However, the thermal conductivity …

Influences Of Suppressing Additive Malachite Green On Superconformal Cobalt Filling And Nucleation, Xiao-Chuan Ma, Ya-Qiang Li, Pei-Xia Yang, Jin-Qiu Zhang, Mao-Zhong An

Journal of Electrochemistry

As the semiconductor integrated circuits evolve into 7 nm technology and beyond, the resistance of the Cu filling at back-end-of-line interconnects no longer linearly scales with dimension. The metal Co with lower mean free path can be used to replace Cu for reducing the line resistance caused by the scattering on the outer surface and grain boundary in the smaller and smaller size. In this study, CoSO₄ was used as the main salt, boric acid as a buffer and malachite green (MG) as an inhibitor for further research. According to the electrochemical cyclic voltammetric (CV) curves by using a …

Study On Low Voltage Electrodeposition Of Diamond-Like Carbon Film, Li Wang, Min-Xian Wu, Jun Li, Yan-Li Chen, Wen-Chang Wang, Zhi-Dong Chen

Journal of Electrochemistry

Diamond-like carbon (DLC) films are receiving a lot of attention from the scientific community, thanks to the promise of DLC films for applications in microelectronics and optoelectronics. Usually, electrodeposition is the preferred common technique because of low cost, large deposition area and simplicity of the setup. However, when carbon films are electrodeposited on a stainless steel, high cell voltages (≥1000 V) are required owing to the low electric conductivity of the organic solvents. This work has developed a new electrolyte system that could achieve carbon deposition on a stainless steel under a low applied cell voltage. The DLC films were …