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Passive devices

The optical power A oscillates between tlie guides depending upon tlie propagation distance. Clearly, by controlling z, (3 and k, a wide variety of passive devices (beam splitters, combiners, attenuators, and interferometers) can be readily constmcted. [Pg.2868]

Dielectric Film Deposition. Dielectric films are found in all VLSI circuits to provide insulation between conducting layers, as diffusion and ion implantation (qv) masks, for diffusion from doped oxides, to cap doped films to prevent outdiffusion, and for passivating devices as a measure of protection against external contamination, moisture, and scratches. Properties that define the nature and function of dielectric films are the dielectric constant, the process temperature, and specific fabrication characteristics such as step coverage, gap-filling capabihties, density stress, contamination, thickness uniformity, deposition rate, and moisture resistance (2). Several processes are used to deposit dielectric films including atmospheric pressure CVD (APCVD), low pressure CVD (LPCVD), or plasma-enhanced CVD (PECVD) (see Plasma technology). [Pg.347]

Fundamental tothis strategy isaprocedurefordassificationofdevicesintooneoffour categories classes I, Ila, I Ib or 111. Manufacturers must classify their devices according to criteria and rules set out in Annex IX to the directive, as amended. As a first step, the manufacturermustclearlydefinetheintendeduseofthedeviceintermsof (i) degree of invasiveness (ii) mode of action, whether active or passive device (iii) the duration of contact with the patient and (iv) impact on the body, local versus systemic effect. [Pg.172]

Many of these steps include CVD, and CVD is now a major process in the fabrication of monolithic integrated circuits (IC), custom and semi-custom ASIC s, active discrete devices, transistors, diodes, passive devices and networks, hybrid IC s, opto-elec-tronic devices, energy-conversion devices, and microwave devices. [Pg.346]

Resistors, which are passive devices limiting the flow of electrical current in proportion to the applied voltage and usually made of tantalum, nichrome, titanium, or tungsten. [Pg.348]

LOPA is a semi-quantitative tool for analyzing and assessing risk. This method includes simplified methods to characterize the consequences and estimate the frequencies. Various layers of protection are added to a process, for example, to lower the frequency of the undesired consequences. The protection layers may include inherently safer concepts the basic process control system safety instrumented functions passive devices, such as dikes or blast walls active devices, such as relief valves and human intervention. This concept of layers of protection is illustrated in Figure 11-16. The combined effects of the protection layers and the consequences are then compared against some risk tolerance criteria. [Pg.500]

However optical applications of PS are not restricted to passive devices, ft has been shown that electroluminescent solid-state devices based on silicon are feasible. [Pg.225]

The incorporation of Cr" + ions in crystals is presently an active research subject, due to the possibility of realizing new broadly tunable solid state lasers in the infrared, which will operate at room temperature. Moreover, the spectroscopic properties of this ion are particularly useful in the development of saturable absorbers for Q-switching passive devices. At the present time, Cr + YAG is the most common material employed as a passive Q-switch in Nd YAG lasers. This is because the ions provide an adequate absorption cross section at the Nd + laser wavelength (1.06 /um), together with the good chemical, thermal, and mechanical properties of YAG crystals, which are required for stable operation. [Pg.219]

It is intrinsically safe - the sensors are essentially passive devices. [Pg.260]

Most of the devices used by PSpice can include temperature effects in the model. Most of the semiconductor models provided by Oread include temperature dependence. By default, the passive devices such as resistors, capacitors, and inductors do not include temperature dependence. To make these items include temperature effects, you will need to create models that include temperature effects. The temperature dependence of resistors is discussed in Section 4.G.I. In this section, we will show only how the I-V characteristic of a 1N5401 diode is affected by temperature. The D1N5401 diode model already includes temperature effects so we will not need to modify the model. We will use the standard resistor, which does not include temperature effects. We will continue with the circuit of Section 4.B ... [Pg.203]

Philip West (4) reviewed the status of passive monitors for toxins such as chlorine, S02, vinyl chloride, alkyl lead, benzene, H2S and HCN. Dr. West predicts a bright future for passive monitors. He points out the disadvantages of active monitors and the merits of passive devices. In my opinion, we need more information on precision and accuracy in sophisticated validation studies before we let our hopes rise too high. [Pg.19]

Class I products are passive devices that do not enter the patient s body or contact only the skin. [Pg.166]

Devices requiring the patient s inspiration effort to aerosolize the powder aliquot are called passive devices because they do not provide an internal energy source. Active devices may provide different kinds... [Pg.242]

No active devices are currently marketed, and examples of successful developments are fewer than for passive devices. There are some promising device developments in the late stage but also examples of concepts that failed in development. Also, some less expensive developments are currently being pursued, intended for the local therapy of lung diseases. [Pg.253]

What can be expected in the near and middle future for inhaled powder delivery There certainly will be some more new passive devices to reach the market and the patient, but it seems that a lot of purely mechanical design ideas have been implemented already in the newest generation of multiple-dose DPIs. Most important are audible and visible feedback features that help to improve delivery efficiency and patient compliance. Future improvements also seem possible in reducing dependency of the particle dispersion on actuation flow rate and internal device resistance. The next or over-next generation of multiple-dose devices also may incorporate lean, inexpensive, but rugged electronics... [Pg.264]

It should also be mentioned that the parallelization of reactors raises other problems such as the maldistribution of the reactants to the single units. While here usually passive devices such as flow restrictors are effectively applied, more severe problems are encountered if the process temperature should be controlled actively. One solution is to heat the whole micro reactor (assuming isothermal conditions due to large heat transfer coefficients) at a constant temperature controlled by the temperature of the flow at the reactor exit [13]. [Pg.609]

Catalytic converters were first installed in U.S. cars in 1976.20 21 They were passive devices in that they were simply placed in the exhaust with no communication with the engine or its control strategy. It catalyzed the oxidation of the unburned hydrocarbons (CyHn) and carbon monoxide (CO) emitted during the incomplete combustion of the fuel. In some vehicles excess air was pumped into the exhaust to ensure sufficient oxygen to complete the catalytic oxidation. This resulted in about a 90% reduction of these two pollutants relative to the uncontrolled uncatalyzed vehicle. [Pg.291]

Active/passive device Active devices require input of power, most often low-level (5-24 V) DC, to achieve their specified function, with the ctmse-quence that their output RF power level can exceed RF input powo-. Passive devices, on the other hand, effect some transformation of the input signal without use of any external power source, so that the output power is always less than or equal to the input power. In the following, simple components are specified as active or passive (note that the addition of an electronic control system, e.g., a motor drive to set the value of a variable attenuator, is not considered grounds for calling a component active). The active/passive distinction is made only for circuit components having an input and output, not for measurement instrumentation (e.g., a frequency counter), the output of which is a visual indication or computer bus-compatible signal. [Pg.355]

Personal measurement A measurement collected from an individual s immediate environment using either active or passive devices to collect the samples (USEPA, 1992b). [Pg.400]

Products closest to commercial production are SQUlDs - " and a microwave passive device. A SQUID is a superconducting device containing one or two... [Pg.423]

Dry powder inhalers These are inhalers that typically fall into two general types of commercially available systems single-dose and multidose systems. The multidose systems have been finding increased use in recent years and are generally either passive devices, where the patient provides the energy to disperse the drug powder in a stream of inspired air, or active devices, in which the energy comes from the device. [Pg.297]

Recommended maintenance and inspection procedures for the safety devices must be provided per NFPA 86 (sect. 5-2.4 and Chapter 10). It shall be the responsibility of the user to establish, schedule, and enforce the frequency of, and the extent of, the maintenance and inspection program. Most of the critical safety devices are passive devices (they only react under abnormal conditions) therefore, they must be inspected frequently to prove that they are operational. Appendix B of NFPA 86 entitled, Example of Operational and Maintenance Checklist, provides examples of various checklists and inspection/maintenance procedures. [Pg.316]


See other pages where Passive devices is mentioned: [Pg.2300]    [Pg.432]    [Pg.370]    [Pg.8]    [Pg.187]    [Pg.92]    [Pg.3]    [Pg.243]    [Pg.254]    [Pg.255]    [Pg.428]    [Pg.360]    [Pg.4]    [Pg.575]    [Pg.379]    [Pg.172]    [Pg.218]    [Pg.416]    [Pg.416]    [Pg.2055]    [Pg.53]    [Pg.424]    [Pg.2704]    [Pg.2705]    [Pg.264]    [Pg.2594]   
See also in sourсe #XX -- [ Pg.242 ]




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