Development Of Microtechnology Research Articles

Operando Spectroelectrochemical Imaging of Concentration Fields and Tafel Kinetics in Microfluidic Electrochemical Devices.

With the development of microtechnologies for energy conversion and storage, mass transfer and micromolar concentration variations need to be measured at the microscale. These advances need to be accompanied by novel imaging techniques with the capability of achieving high spatial resolution while detecting very small signal variations (less than 0.1%). Thus, in this study, a new microscopy technique is proposed based on a combination of electrochemical impedance spectroscopy (EIS) and visible imaging spectroscopy to measure the concentration fields at the micromolar scale in operando microfluidic fuel cells (MFCs). This technique exploits EIS modulation and Fourier analysis to reduce the noise during concentration field imaging. A mass transfer model in the periodic regime is derived to validate the measurements and to estimate the Tafel kinetics and mass diffusivities during potassium permanganate reduction from only one potential measurement. The proposed imaging method and mathematical framework presented in this study can be used to study binary electrochemical reactions without gas production.

Microneedle-based ocular drug delivery systems - recent advances and challenges.

Eye diseases and injuries constitute a significant clinical problem worldwide. Safe and effective delivery of drugs to the eye is challenging mostly due to the presence of ocular barriers and clearance mechanisms. In everyday practice, the traditional eye drops, gels and ointments are most often used. Unfortunately, they are usually not well tolerated by patients due to the need for frequent use as well as the discomfort during application. Therefore, novel drug delivery systems with improved biopharmaceutical properties are a subject of ongoing scientific investigations. Due to the developments in microtechnology, in recent years, there has been a remarkable advance in the development of microneedle-based systems as an alternative, non-invasive form for administering drugs to the eye. This review summarizes the latest achievements in the field of obtaining microneedle ocular patches. In the manuscript, the most important manufacturing technologies, microneedle classification, and the research studies related to ophthalmic application of microneedles are presented. Finally, the most important advantages and drawbacks, as well as potential challenges related to the unique anatomy and physiology of the eye are summarized and discussed.

Microtechnology in computer optics

The article briefly describes the development of microtechnology in the field of diffractive computer optics. The author presents the material based on the development of the laboratory of micro- and nanotechnology of Image Processing Systems Institute of the RAS. The creator and head of this laboratory was Doctor of Technics, Professor Alexey Volkov, a well-known expert in the field of electronic and vacuum technologies. The author analyzes the impact of scientific results of Professor A.V. Volkov on the development of diffractive optics.

Micro-optical Components for Bioimaging on Tissues, Cells and Subcellular Structures.

Bioimaging generally indicates imaging techniques that acquire biological information from living forms. Among different imaging techniques, optical microscopy plays a predominant role in observing tissues, cells and biomolecules. Along with the fast development of microtechnology, developing miniaturized and integrated optical imaging systems has become essential to provide new imaging solutions for point-of-care applications. In this review, we will introduce the basic micro-optical components and their fabrication technologies first, and further emphasize the development of integrated optical systems for in vitro and in vivo bioimaging, respectively. We will conclude by giving our perspectives on micro-optical components for bioimaging applications in the near future.

Microfluidic Cell Culture Platforms to Capture Hepatic Physiology and Complex Cellular Interactions.

Animal models such as rats and primates provide body-wide information for drug and metabolite responses, including organ-specific toxicity and any unforeseen side effects on other organs. Although effective in the drug-screening process, their translatability to humans is limited because of the lack of high concordance and correlation among enzymatic mechanisms, cellular mechanisms, and resulting toxicities. A significant mode of failure for safety prediction in drug screening is hepatotoxicity, resulting in ∼30% of all safety-related drug failures and withdrawals from the market. The liver is a multifunctional organ with diverse metabolic, secretory, and inflammatory response roles and is essential for maintaining key body functions. Conventional cell culture platforms (such as multiwell plate cultures) and metabolic enzyme systems (microsomes, cytochrome P450 enzymes) have been routinely used to assess drug pharmacokinetics and metabolism. However, current in vitro models often fail to recapitulate the complexity and dynamic nature of human tissues, imposing a heavy reliance on in vivo testing using preclinical species that have metabolic processes, disease mechanisms, and modes of toxicity distinct from humans. Recently, microphysiological systems (MPS) have gained attention as powerful tools with the potential to generate human-relevant information that can supplant and fill the gap of knowledge between preclinical animal models and simpler, conventional in vitro cell culture systems. Developments in microfabrication technologies for generating complex microfluidic systems, along with the ability to establish and maintain multicellular models to capture dynamic, human-relevant behavior, have provided new avenues to generate such physiologically relevant systems. These MPS platforms, when designed and developed with in vivo-derived design parameters, have the potential to capture key aspects and better mimic organ functionality. In this review, we discuss developments in microtechnologies for fabricating, establishing, and maintaining hepatic cell culture systems, with a specific focus on models that aim to capture in vivo physiology in vitro. By designing microscale systems to impart specific in vivo physiologic parameters, it is possible to create a dynamic system that can capture multiple aspects of the hepatic microenvironment, bringing us closer to a comprehensive in vitro testing platform for hepatic responses and toxicities.

Design of High-Reliability Micro Safety and Arming Devices for a Small Caliber Projectile.

With the development of micro technology, the fuse for small-caliber projectiles tends to be miniaturized and intelligent, the traditional fuse no longer meets the requirements. In this paper, we demonstrate a micro safety and arming (S & A) device with small volume and high reliability in small caliber projectile platforms. The working principle of S & A devices is that a centrifugal insurance mechanism could deform under a centrifugal load and thus cause fuse safety arming. The centrifugal insurance mechanism is designed theoretically, verified by simulation and experimental methods. The experimental results show that, when the rotary speed is over 36,000 rpm, the fuse was armed safely. In addition, the experimental, simulation, and theoretical results are basically consistent, and indicate that the centrifugal insurance mechanism meets the expected criteria.

Player-Tracking Technology: Half-Full or Half-Empty Glass?

With the ongoing development of microtechnology, player tracking has become one of the most important components of load monitoring in team sports. The 3 main objectives of player tracking are better understanding of practice (provide an objective, a posteriori evaluation of external load and locomotor demands of any given session or match), optimization of training-load patterns at the team level, and decision making on individual players' training programs to improve performance and prevent injuries (eg, top-up training vs unloading sequences, return to play progression). This paper discusses the basics of a simple tracking approach and the need to integrate multiple systems. The limitations of some of the most used variables in the field (including metabolic-power measures) are debated, and innovative and potentially new powerful variables are presented. The foundations of a successful player-monitoring system are probably laid on the pitch first, in the way practitioners collect their own tracking data, given the limitations of each variable, and how they report and use all this information, rather than in the technology and the variables per se. Overall, the decision to use any tracking technology or new variable should always be considered with a cost/benefit approach (ie, cost, ease of use, portability, manpower/ability to affect the training program).

Développement de microcapteurs chimiques à effet de champ pour la détection enzymatique

The development of microtechnologies has resulted in new applications for the chemical, biochemical and biological analysis in liquid phase. This paper presents the main transduction principles of the chemical field effect transistor (ChemFET) for the pH measurement, and then describes the different studies realized for the enzymatic detection of biochemical species.

Non-linear stochastic optimal control of acceleration parametrically excited systems

Acceleration parametrical excitations have not been taken into account due to the lack of physical significance in macroscopic structures. The explosive development of microtechnology and nanotechnology, however, motivates the investigation of the acceleration parametrically excited systems. The adsorption and desorption effects dramatically change the mass of nano-sized structures, which significantly reduces the precision of nanoscale sensors or can be reasonably utilised to detect molecular mass. This manuscript proposes a non-linear stochastic optimal control strategy for stochastic systems with acceleration parametric excitation based on stochastic averaging of energy envelope and stochastic dynamic programming principle. System acceleration is approximately expressed as a function of system displacement in a short time range under the conditions of light damping and weak excitations, and the acceleration parametrically excited system is shown to be equivalent to a constructed system with an additional displacement parametric excitation term. Then, the controlled system is converted into a partially averaged Itô equation with respect to the total system energy through stochastic averaging of energy envelope, and the optimal control strategy for the averaged system is derived from solving the associated dynamic programming equation. Numerical results for a controlled Duffing oscillator indicate the efficacy of the proposed control strategy.

A novel photon detector made of silicon and carbon nanotubes

The use of silicon and the development of micro-technology made possible the transition from macro- to micro-detection systems and of very large-scale integration systems for microelectronics. The most powerful micro-detector recently developed is the Silicon PhotoMultiplier (SiPM) that allows a pixel dimension of microns in a hundred-pixel array. The use of nanotechnology opens now a new field of applications in which materials are “built” chemically up to the desired dimensions. This process allows the realization of complex structures that have finely pixelled sub-micron dimensions and that are cheap, light, and easy to produce. Between the materials suitable for nanotechnology, carbon nanotubes (CNT) play a main role because of their facility of being produced and their unique mechanical and electrical properties. They can be grown chemically in a very easy and cheap way, assembled in the desired geometry and directly connected to readout electronics devices. In addition, they can be coupled to silicon substrates to obtain mixed micro–nano structures with intermediate electronic properties. The first radiation detector using CNTs grown through a chemical vapour deposition (CVD) process has been realized using a sapphire substrate. This device, sensitive to the radiation in the range from 220 to more than 850 nm, exhibits a relevant increase in the photocurrent toward UV wavelengths both with continuous light and with pulsed radiation. This opens the door to the realization of a new kind of low-cost radiation detector with sub-micron spatial resolution and high sensitivity in the UV radiation region. In order to avoid the large dark current observed, a new detector has been realized using an p-doped silicon substrate. Electrical and optical properties of this novel detector have been intensively studied as well as the coupling between nanotubes and silicon. The strong matching found between the two different materials suggests the possibility of realizing a single photon detector with high quantum efficiency in the UV wavelength region.

Some examples of current diffusion bonding applications

AbstractIn recent years a renaissance of diffusion bonding can be observed. Beside applications in the aerospace industry more and more industrial users take advantage of the solid state joining process. The progressive development of micro technologies results from the systematic miniaturization efforts for electrical, optical and mechanical components. A major role for this is taken by the application of scale effects. Today, micro structured‐components are already deployed in telecommunication, mechanical engineering, medicine‐ and biotechnology.During this continuous top‐down process the performance of a component should at least be equal or rather enhanced as compared to the conventional processed part. Increasing computational power needs a safely controlled and managed heat generation and distribution in any of such components.This is not only important for electronic devices, but also for tools used for micro injection molding. With the combination of machining or laser cutting and subsequent diffusion bonding it is possible to freely design and manufacture the required parts with an inside structure. In this paper an enhanced process chain for production of parts by a lamination technology, which is capable to solve scale restrictions, is presented as well as application examples and process specific features, Fig. 1.

Miniaturisation of analytical steps: necessity and snobbism

Automation and miniaturization were two widespread trends implicitly included in the research priorities of most scientific fields in the last few decades of the twentieth century. One result of the latter trend was the development of microtechnology, which has by now been superseded by nanotechnology by virtue of the advantages of small devices over macroscale systems. Analytical chemistry has also taken advantage of these trends in general and of nanotechnology in particular. The advantages thus gained include accurate spatial control over reagents and samples, increased throughput, automatability—which is absolutely mandatory, the ability to handle picoliter volumes of undiluted reactants—which saves reagents and sample, compatibility with a wide range of detection systems, the availability of a variety of materials for manufacturing at relatively low cost, design flexibility, the ability to perform multiple tasks (e.g. for the simultaneous development of several sample-preparation steps such as dissolution, extraction, or preconcentration) and improvements derived from the reduced dimensions used (e.g. in nanochromatography or chip-based separations). The development of portable miniaturized devices has facilitated the decentralization of analyses, a primary goal for this century, by enabling real time, in situ, on-line, in-vivo monitoring of processes without the need for skilled operators or special equipment [1]. There is no doubt that miniaturization and nanotechnology have contributed enormously to the emergence and development of new research areas which have brought about true revolutions, particularly in bioanalysis.

Prospects for microtechnology and nanotechnology in bioengineering of replacement microvessels.

Due to its anticipated curative potential, therapeutic angiogenesis recently became a major preoccupation for the biomedical research community. Most of the related work reported to date employs either biochemical or genetic tools. To identify opportunities for application of the current developments in microtechnology and nanotechnology to the field of therapeutic angiogenesis. Survey of recent English-language literature on microvascular tissue engineering in the context of therapeutic angiogenesis. We include our results regarding the role played by microtopographical cues in the progression of angiogenesis, such as those produced during processing of the extracellular matrix by chronic inflammatory cells. While notable accomplishments have been identified in the field of tissue engineering of larger vessels, reports on purposeful assembly of microvascular structures with the ability to be transferred in vivo by implantation are still scarce. Under these circumstances, we suggest the development of a new class of implantable biomedical microdevices, that is, "angiogenesis assist devices" (or "angiochips"), and we indicate some of their conceivable applications.

Overview : Recent Topics on Micro Visualization in Japan

Micro technology is one of the key technologies in advanced engineering of various fields. Analysis of micro scale thermal and fluid dynamics is also important factor in the development of micro technology, such as flow around micro machine, micro-fluidic, micro heat exchanging system, micro chemical and biomedical analysis system, and so on. Though the micro scale visualization is accompanied by some difficulties caused by the scale effect, it is effective in order to understand phenomena in micro scale flow. Recent topics on the method of micro flow visualization and applications in Japan are summarized.

Reliability assessment for development of microtechnologies

In recent years, developments in the micro electronics industry have focused on semiconductors and semiconductor processes. However, microcircuit assembly technologies have lagged chip development. This has spurred research in interconnection and packaging creating many new technologies and enhancing integration. These new microelectronic technologies are enabling micro systems, and resulting in products, from portable work stations to advanced automotive electronics. This evolution of technology has also created the need to reexamine how we achieve a reliable system. Clearly, in highly competitive marketplaces, reliability is a key element in achieving successful products. To achieve a reliable product in a cost effective manner, “upstream problem solving” must be employed which focuses on root cause of failure. This paper provides an overview of the reliability assessment process needed to achieve effective microsystem development. A case study of reliability in a complex multi-chip module is presented which includes an assessment of the stochastic nature of via fatigue by applying Monte Carlo simulations.

Use of atomic force microscopy for surface roughness determination of ball bearings

Abstract Since the development of microtechnology and nanotechnology, new analytical methods have been developed, and, among them, atomic force microscopy has been especially used for the characterization of the surface topography of a very wide range of materials on a submicrometer scale. A great advantage of this method is not only the possibility of imaging surfaces with unprecedented resolution but it also can perform quantitative evaluation of selected surface features, including statistical analysis of the corrugations, which permits the roughness parameters to be determined. Such measurements of the surface roughness were performed on small ball bearings and the results showed that the roughness data can be very different, even under the “grade 3”, i.e. the lowest surface roughness value given in the AFBMA standard.

Heat Transfer Regimes in Microstructures

Submicron dimensions are the hallmark of integrated electronic circuits, photovoltaic cells, sensors, and actuators. The design of these devices requires heat transfer analysis. Often it is not known to the designer whether a given microstructure can be analyzed using macroscale heat transfer theory, i.e., a method not considering the size dependence of a transport property such as thermal conductivity. This study develops regime maps showing the boundary between the macroscale and microscale heat transfer regimes. The maps relate the geometric dimension separating the two regimes to temperature for conduction in solids, to temperature, pressure, and Reynolds number for convection in gases, and to the temperature of the emitting medium for radiative transfer. The material purity and defect structure strongly influence the regime boundaries. Microstructures pertaining to a given technology are marked on these maps to determine whether macroscale heat transfer theory is applicable. By marking regions on the maps for the expected future development of microtechnologies, research needs in microscale heat transfer can be anticipated.

The Social Basis of the Microelectronics Revolution.

Part 1 The dominant social constituency of a technological process methodological aspects structure of the book. Part 2 The social basis of the United States research and development system from the Second World War to the present: the role of the military the aftermath of the Second World War crisis and loss of confidence the resurgence of the power complex contradictory trends the case against the military burden. Part 3 The social shaping of United States microtechnology from the Second World War to the mid 1970s: the legacy of the Second World War the government-military-led development of the post-war period 1945-mid 1960s - industrial control, computer systems, semiconductors the decline of government-military influence. Part 4 The current development of microtechnology: re-strengthening the links between corporate capital, government, the military and science the renewed influence of the military on the current development of microtechnology - the VHSIC and Sematech programmes, the strategic computing plan (SCP), the ICAM and man tech programmes, the strategic defense initiative (SDI) conflicting views about the wisdom of the renewed military drive. Part 5 The current development of microtechnology II: convergence of technologies and capital in the electronics industry - AT and T and IBM on a collision course, convergence of capital electronics competition on a global scale, evolution of United States, European and Japanese electronics markets, current trends in the global battle for control of electronics markets, global alliances in the battle for control of the electronics infrastructure. Part 6 Foundations of the future I: dissecting the dominant social constituency of the United States microtechnology, the science constituent, the capital constituent, the government and military constituents some conceptualizations of the United States social complex of power the power complex as dominant social constituency of microtechnology. Part 7 Foundations of the Future II: the present constituency of power - the path ahead searching for a new social constituency.

Kinaesthesia in Music and its Implications for Developments in Microtechnology

This paper takes the view that kinaesthesia, processes involving neuro muscular sensation, should be the central and unifying component in any psychological model for music learning. It maintains that engagement in music activities, which consciously encourages the processes of kinaesthesia, helps to bring about the closer association of thinking and feeling. The paper develops the notion that this form of musical ‘knowing’, which is based on the interrelationships between muscular, perceptual and cognitive awareness, is the essential ingredient of musically sensitive and imaginative behaviour. Having established these principles, the paper explores those recent developments in music microtechnology which appear to support and develop these processes.

An Assessment of the Benefits of Micro Technology in Music Therapy

This article aims to summarise the main facilities made available to the music therapist by developments in micro technology, and to assess their benefits. All issues discussed relate to the author's own personal experience of using such equipment in working with handicapped adults. The survey covers computer hardware and software developments, from specially developed computer input devices to facilities made available by MIDI (Musical Instrument Digital Interface).