Multifunctional applications

1. Thanks to the development of microprocessor electronics, digital systems can be found everywhere in industry from biomedical engineering to fashion computer design. New, computer-assisted technologies have given birth to interdisciplinary sciences such as computational biology, neural robotics, artificial intelligence and combinatorial drug production. With a very high signal-to-noise ratio and negligible error coefficient, digital systems have massively replaced old analog devices. Still, those systems do not have the information capacity of natural biologic sensors, which are entirely analog. Analog systems are capable of processing a large quantity of information at a much higher speed than the digital ones.

2. Biological sensors, operating at the complex nature-animal interface, process gigantic volumes of information in real time. Biological sensors have also a remarkable capability to operate as multifunctional devices. The sensors located in the tips of our fingers are not only touching receptors, they are pressure sensors, shape-memory devices, temperature sensors, and liquid-viscosity sensors as well. The human eye is not just a photographic camera but a complex system for image processing, color detection, light-intensity calibration, and motion detection. These sensors transform mechanical, thermal, and optical energies into electrical signals sent to the brain, which provides feedback information to the sensors through sophisticated pattern recognition procedures. Without the brain's feedback and pattern recognition capabilities, sensors alone would not be able to achieve high resolution, sensitivity, and selectivity.

3. Sensors rarely operate in a simple environment where only one parameter changes. Most physical and chemical sensors operate in complex environments where various parameters change simultaneously. The most critical problem is cross-sensitivity. A typical example is chemical sensors. Some electrochemical gas sensors have very high sensitivity in a pure gas environment but perform poorly in a gas mixture. Many multidisciplinary groups are attempting to develop advanced sensors with multifunction operations, similar to biological ones.

4. Advanced sensors for detecting simultaneously various parameters such as temperature, pressure, radiation, gas and vapor concentration, odor, acceleration, inertia, electric and magnetic fields, and more must provide not only high signal-to-noise ratio in a wide dynamic range but also good cross-sensitivity. In general, the sensors consist of two elements: a detector and a platform that communicates with the detector through an active interface with variable electrical, mechanical, optical, or chemical impedance. The platform must be able to generate output electrical signals carrying the information provided by the detector.

5. Because today's silicon micromachining technology is highly sophisticated, MEMS employing silicon offer many advantages in the design of multifunctional sensors. Silicon, an ideal electronic material and also a high-performance mechanical material, can be micromachined by using chemical and electrochemical etch techniques. All classic technologies used in microelectronics manufacturing, including photolithography, diffusion, oxidation, ion implantation, and metal coating, can be applied in silicon micromachining.. A typical micromachining technique is based on SOI silicon wafers and wafer bonding. The process flow is based on wafer bonding of SOI wafers and can be used to manufacture various integrated resonant devices and systems for adaptive optics. MEMS technologies offer the potential for complimentary multifunctional devices by integrating various systems and principles.

V. Say whether the following statements are true or false.

	Digital systems were changed by analog devices.
	Natural biologic sensors possess the same information capacity as digital systems.
	Biological sensors unable to process large volumes of information in real time.
	Biological sensors can be named as multifunctional devices.
	The problem of cross-sensitivity isn’t considered to be acute nowadays.
	There are three main parts of the sensors: a detector, a platform and environments.
	Germanium is widely used in multifunctional micro-electromechanical sensor systems.

VI. Read paragraph 1 of the text and answer the questions.

	Where are digital systems used nowadays?
	Why have old analog systems been changed by digital systems?
	What systems have the highest information capacity?

VII. Read paragraph 2 and say what capabilities biological sensors have.

VIII. Look through paragraphs 2 and 3 and find English equivalents of the following words and word combinations: обрабатывают гигантские объёмы информации, замечательная способность, расположенные, также, сложный, обработка изображения, определение, мозг, сложные процедуры, распознавание, одновременно, чистая, пытаются, подобный.

IX. Read the first sentence of paragraph 4 and mark pauses. Divide it into sense groups, find out the means of connection between the words in each group.

X. Translate paragraphs 4 and 5 into Russian.

XI. Make an outline of the text.

XII. Speak about different kinds of sensors and their distinctive features.

Part B

I. Define the meaning of the “x” word.

approximation: approximately = приближение: х

density: dense = плотность: х

loss: lossless = потеря: х

frequency: frequent = частота: х

indicate: indicator = показывать: х

oscillate: oscillation = колебаться: х

modify: modification = модифицировать: х

dependence: depend = зависимость: х

determine: determination = определять: х

II. Find in the list the following parts of speech: a) nouns; b) adjectives;

c) adverbs; d) verbs.

Resonator, mechanical, perturbation, electrical, originate, medium, occur;

different, conductivity, chemical, performance, depend, various, frequently, external, lower, decrease, accuracy, measurement, substantially, generation.

III. Complete the sentences with the following words:

higher accuracy, to be based, to have been used, to be deposited, to be loaded, electrical perturbations, solid.

	The most common sensor platform ….. on piezoelectric devices.
	Different kinds of resonators …. in the design of multifunctional physical and chemical sensors.
	Frequency may be measured with … that any other parameter.
	Thin-film coatings … on the resonator.
	If the resonator … with a thin film, the boundary conditions will be modified.
	… can occur in metal films.
	Various loading effects in liquid and … media damp the oscillations of the resonator.

IV. Read the text and say which paragraph contains the information about the influence of different kinds of perturbations in solid and fluid media on the sensor performance.