Distribution of man-made radioactivity in the North PacIific through summer 1955

The radioactivity which originated from the Bikini and Eniwetok tests in the spring of 1954 was transported mainly to the west, then to the north toward the coast of J a.pan, and finally down south a.long the Kuroshio Current by summer 1955…

A study on the foaming of sea water Part I

In spite of the fact that many marine observers are aware that sea water has a remarkable foaming capacity, there has not been any scientific study of this subject. However, the foaming capacity may be of considerable importance in oceanography. For instance, there must be an intimate relation between the Beaufort scale and the foaming of sea water, since there is no doubt that aspects of white waves generated on the sea by winds largely depend on this effect

The measurement of the viscosity coefficient of sea water

In an old study by Ruppin and Krummel (Krümmel, 1907: 281), the viscosity of sea water was measured by the method of Wil. Ostwald. However, at that time the data for the viscosity of sea water were given relative to that of pure water at 0° C. Since then several precise measurements (Dorsey, 1940: 182) have been made and reliable data obtained, and therefore it is necessary to determine more exact values for the viscosity of sea water

Temperature and voltage measurement for field test using an Aging-Tolerant monitor

Measuring temperature and voltage (T&V) in a current VLSI is very important in guaranteeing its reliability, because a large variation of temperature or voltage in field will reduce a delay margin and makes the chip behavior unreliable. This paper proposes a novel method of T&V measurement, which can be used for variety of applications, such as field test, online test, or hot-spot monitoring. The method counts frequencies of more than one ring oscillator (RO), which composes an aging-tolerant monitor. Then, the T&V are derived from the frequencies using a multiple regression analysis. To improve the accuracy of measurement, three techniques of an optimal selection of RO types, their calibration, and hierarchical calculation are newly introduced. In order to make sure the proposed method, circuit simulation in 180-, 90-, and 45-nm CMOS technologies is performed. In the 180-nm CMOS technology, the temperature accuracy is within 0.99 °C, and the voltage accuracy is within 4.17 mV. Furthermore, some experimental results using fabricated test chips with 180-nm CMOS technology confirm its feasibility

Temperature and Voltage Estimation Using Ring-Oscillator-Based Monitor for Field Test

Field test is performed in diverse environments, in which temperature varies across a wide range. As temperature affects a circuit delay greatly, accurate temperature monitors are required. They should be placed at various locations on a chip including hot spots. This paper proposes a flexible ring-oscillator-based monitor that accurately measures voltage as well as temperature at the same time. The measurement accuracy was confirmed by circuit simulation for 180 nm, 90 nm and 45 nm technologies. An experiment using test chips with 180 nm technology shows its feasibility.2014 IEEE 23rd Asian Test Symposium (ATS), 16-19 Nov. 2014, Hangzhou, Chin

Reduction of NBTI-Induced Degradation on Ring Oscillators in FPGA

Ring Oscillators are used for variety of purposes to enhance reliability on LSIs or FPGAs. This paper introduces an aging-tolerant design structure of ring oscillators that are used in FPGAs. The structure is able to reduce NBTI-induced degradation in a ring oscillator\u27s frequency by setting PMOS transistors of look-up tables in an off-state when the oscillator is not working. The evaluation of a variety of ring oscillators using Altera Cyclone IV device (60nm technology) shows that the proposed structure is capable of controlling degradation level as well as reducing more than 37% performance degradation compared to the conventional oscillators.The 20th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2014), Nov 19-21, 2014, Singapor