Decade counter

EXERCISE B-3 Design and simulate a 4-bit decade counter. The counter should be initialized to 0000 at the start of the simulation. 

DDNP = diazodinitrophenol 94 deblai = muckpile 219 decade counter (chronograph) 90 decapitation de la charge = cut of 67 deflagration 75 80 86 249 deflagration point 75 DEGDN, DEGN = diethyleneglycol dinitrate 96... 

Figure 23.20. Asynchronous decade counter. From S. P. Perone and D. O. Jones, Digital Computers in Scientific Instrumentation, New York McGraw-Hill, 1973, by permission of the publisher. Copyright 1973 by McGraw-Hill, Inc.

Since we are accustomed to thinking in terms of the decimal (base 10) number system, decade counters are often used in interface systems. They not only count in powers of 10 but can be used to divide clock frequencies in decade rather than binary steps. The decade counter presented in Figure 23.20, along with its timing chart, follows the count sequence presented in Table 23.7. The BCD Binary Coded Decimal) number system is a binary representation of the decimal number system. 

The preset count value takes the form pqxlO r where r is set to a value in the range 0 to 6, and pq is a two-digit number taking values from 0 to 99. This information is loaded in the down counters A42 (units) and A43 (tens). The power r is used to control the output of the six decade counter A51 if r = 0, the output has the same number of pulses as the input in general, the output corresponds to a division by 10 r. 

In this Instrument the Input signals are Initially divided by 2 In a flip-flop, and further divided by a series of decade counters according to the range selected. It Is the rate of the output signal from this block that Is determined by the Instrument. We just refer to the part of the Instrument responsible for this determination, for the other one Is just another example of a counter. The block diagram of this part Is shown In Fig. 8.5 a short description of Its operation follows. 

Measurement of specific activity. The half-life of a nuclide can be readily calculated if both the number of atoms and their rate of decay can be measured, i.e., if the activity A and the number of atoms of P can be measured, then X is known from A = XP. As instrumentation for both atom counting and decay counting has improved in recent decades, this approach has become the dominant method of assessing half-lives. Potential problems with this technique include the accurate and precise calibration of decay-counter efficiency and ensuring sufficient purity of the nuclide of interest. This technique provides the presently used half-lives for many nuclides, including those for the parents of the three decay chains, U, U (Jaffey et al. 1971), and Th. 

In the last four to five decades national health care expenditures for all types of health-related transactions, including dental, medical, hospital, prescription, and over-the-counter (OTC) drugs, has grown from about 5% of the country s gross domestic product (GDP) (national expenditures on all goods and services) to nearly 14% of the GDP today. Total health expenditures in the United States are now well over 1 trillion annually. 

An electrospray is generally produced by the application of an electric field to a small flow of liquid from a capillary tube toward a counter electrode. The principles of electrospray as applicable to mass spectrometry and the mechanisms involved have been a subject of intense debate over the last decade and have been addressed even before that. This is evident from the discussions in the 2000 issue of the Journal of Mass Spectrometry (e.g., Mora11), the book by Cole,12 and several reviews.8,10 13 14 Here we present a summary encapsulating the relevant observations and direct the readers to the above articles for a more elaborate account. 

OD Detectors are the classical proportional counters that are used in laboratory goniometers for decades. Because every point of reciprocal space is measured with the same cell, the detector response is uniform by definition. 

Just as a Coulter Counter or a flow cytometer can automate or at least increase efficiency in counting heterospecific pollen transfer, use of artificial germination media still is an effective method of screening for pollen allelopathy. The fundamental approach recommended has not changed much in the last decade, i.e. sequentially dilute extracts from non-macerated... 

Initial studies with PHOX indicated a lack of an anion effect, replacement of PFg by SbFg, or BF4 as counter ion had no apparent effect on the overall reaction. However, nearly all reported catalysts within the last decade utilize BArp as a counterion, perhaps for the higher catalyst stability, easier handling, and general reactivity toward a broader range of substrates. 

During the past decades, the scope of Lewis acid catalysts was expanded with several organic salts. The adjustment of optimal counter anion is of significant importance, while it predetermines the nature and intensity of catalytic Lewis acid activation of the reactive species. Discovered over 100 years ago and diversely spectroscopically and computationally investigated [131-133], carbocations stiU remain seldom represented in organocatalysis, contrary to analogous of silyl salts for example. The first reported application of a carbenium salt introduced the trityl perchlorate 51 (Scheme 49) as a catalyst in the Mukaiyama aldol-type reactions and Michael transformations (Scheme 50) [134-142]. 

In short, there are reasons to be concerned about the philosophy and practice of psychiatric diagnosing. In many ways, developments over the past two decades run counter to what I believe to be the diagnostic prerequisites for fruitful biological psychiatric research. I presume this to be a major reason that, so far, biology has made no significant contributions to diagnosing mental disorders. 

There has evolved over the past three decades a set of general concepts that have revolutionized the way we regard and study systems in nature. Their basic premises run counter to the Newtonian reductionistic approaches and might thus be labelled post-Newtonian concepts. The central theme of this new philosophy is the recognition that the behaviour and properties of a system are non-linear combinations of the subsystems. Such a system is endowed with complexity and displays specific properties that emerge from dynamic interactions between the subsystems. We discuss briefly complexity and emergence as the two pillars of post-Newtonian thought. 

By the first decade of the 20th century, however, there was growing evidence that the untrammeled use of over-the-counter medicines was creating serious social consequences. Besides the dangers of ineffective or contaminated patent medicines, drugs such as opium, morphine, and heroin were very addictive. 

Things didn t get much better in the later decades of the nineteenth century. Cocaine and opiates were used as over-the-counter "medicines." Of course, the most famous was Coca-Cola, which actually did contain cocaine in its early days. 

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