Miracle-dz/UniFAR-FTUs huggingface dataset:
Room-temperature demonstration of low-voltage and tunable static memory based on negative differential conductance in silicon single-electron transistors

A static memory based on negative differential conductance (NDC) in silicon single-electron transistors is proposed. We fabricate a room-temperature (RT) operating single-hole transistor (SHT) in the form of an ultranarrow wire channel metal-oxide-semiconductor field-effect transistor (MOSFET), and observe clear NDC due to large quantum level spacing of an ultrasmall dot at RT. By serially connecting an SHT showing NDC and a p-type MOSFET acting as a load on a single chip, gate-controllable memory operation is demonstrated at the supply voltage of 0.2V at RT. The proposed memory features high compatibility with the existing very-large-scale integrated circuits, compact size, low-voltage, and tunable operation.
A Survey of Radar Rain Measurement Techniques

Abstract Several methods used to estimate rainfall rate R are surveyed. The distribution N(D) of drop sizes is of central importance in determining the reflectivity factor Z, attenuation rate K, and R. With single-parameter measurement techniques either of the remotely sensed parameters Z or K can he used to estimate R when gross assumptions on N(D) can be made. If N(D) can be described by a two-parameter distribution, dual measurement techniques can better estimate R without invoking these coarse assumptions. A review is made of three techniques whereby two variables might be measured. 1) dual wavelength in which Z and K are remotely measured, 2) dual polarization in which reflectivity is measured with two orthogonal polarizations, and 3) raingage-radar combinations whereby in situ point measurements of R and radar measurement of Z or R are combined to obtain a better assessment of rain over areas between gages.
IRRIGATION DEVELOPMENT VERSUS HYDROELECTRIC GENERATION: CAN INTERRUPTIBLE IRRIGATION PLAY A ROLE?

Irrigation, under conditions where water has a high opportunity cost, could be interruptible with water use, only occurring when water is plentiful. Pacific Northwest case studies indicate interruption can substantially lessen the opportunity cost of new irrigation developments, although not enough to justify the particular case projects examined. Interruptible operation of existing projects in the case study areas appears desirable.
Investigation of thermal conductivity, viscosity, and electrical conductivity of graphene based nanofluids

Stable and well dispersed functionalized graphene–ethylene glycol (EG) + distilled water nanofluids having graphene nano-sheets (GnS) volume concentration between 0.041 and 0.395 vol. % are prepared without any surfactant. Graphene nano-sheets are prepared from high purity graphite powder by Hummers method followed by exfoliation and reduction by hydrogen gas. Thus, obtained hydrogen exfoliated graphene (HEG) is then functionalized using acid. The graphene nano-sheets are characterized using XRD, TEM, Raman spectroscopy, and FTIR spectroscopy. Thermal conductivity and viscosity measurements are performed both as a function of graphene loading and temperature between 10 and 70 °C. Thermal conductivity enhancement of ∼15% for a loading of 0.395 vol. % f-HEG is observed at room temperature. The measured nanofluid's thermal conductivity is explained well in terms of the expression derived by Nan et al. (J. Appl. Phys. 81, 6692 (1997)), which considers matrix-additive interface contact resistance of mis-orient.
The effects of linear-accelerator noise on the Los Alamos free-electron laser

The optical power produced by the Los Alamos free-electron laser has been flawed by a peristent instability. This instability appears as fluctuations in output power in a frequency band centered around 100 kHz. We have found that the fluctuations are dependent on the strength of the lasing and on variations in the electron micropulse's arrival time. When the lasing is strong, the fluctuations are small; when the lasing is weak, the fluctuations are large. The variations in the electron micropulse's arrival time primarily are due to fluctuations in the accelerator gradients. The primary noise sources in the accelerator are the electron gun and the klystron amplifier chain. In addition, this noise is uncontrolled because of a lack of bandwidth in the feedback controls for the RF system. Appropriate improvements are being made to eliminate these fluctuations in optical power.
Bootstrapping Goodness-of-Fit Measures in Structural Equation Models

Assessing overall fit is a topic of keen interest to structural equation modelers, yet measuring goodness of fit has been hampered by several factors. First, the assumptions that underlie the chi-square tests of model fit often are violated. Second, many fit measures (e.g., Bentler and Bonett's [1980] normed fit index) have unknown statistical distributions so that hypothesis testing, confidence intervals, or comparisons of significant differences in these fit indices are not possible. Finally, modelers have little knowledge about the distribution and behavior of the fit measures for misspecified models or for nonnested models. Given this situation, bootstrapping techniques would appear to be an ideal means to tackle these problems. Indeed, Bentler's (1989) EQS 3.0 and Jöreskog and Sörbom's (forthcoming) LISREL 8 have bootstrap resampling options to bootstrap fit indices. In this article the authors (a) demonstrate that the usual bootstrapping methods will fail when applied to the original data, (b) explain why this occurs, and, (c) propose a modified bootstrap method for the chi-square test statistic for model fit. They include simulated and empirical examples to illustrate their results.
A Theoretical Foundation For The Weighted Checksum Scheme

The weighted checksum scheme has been proposed as a low-cost error detection procedure for parallel matrix computations. Error correction has proved to be a much more difficult problem to solve than detection when using weighted checksums. In this paper we provide a theoretical basis for the correction problem. We show that for a distance d+1 weighted checksum scheme, if a maximum of ici [d/2] errors ensue then we can determine exactly how many errors have occurred. We further show that in this case we can correct the errors and give a procedure for doing so.
Quantal consequences of perturbations which destroy structurally unstable orbits in chaotic billiards

Non-generic contributions to the quantal level density from parallel segments in billiards are investigated. These contributions are due to the existence of marginally stable families of periodic orbits, which are structurally unstable, in the sense that small perturbations, such as a slight tilt of one of the segments, destroy them completely. We investigate the effects of such perturbations on the corresponding quantum spectra, and demonstrate them for the stadium billiard.
The time-dependent ejection velocity histories of HH 34 and HH 111

The southern lobe of HH 34 and the western lobe of HH 111 show remarkable similarities. Both objects have a chain of well aligned knots, ending in well defined bow shocks (HH 34S and HH 11 IV, respectively). In this paper, we derive the past ejection velocity histories from previously published radial velocity measurements of the HH 34 and HH 111 jets. This is done under the assumption that the flows are ballistic. From these reconstructed ejection velocity variabilities, we compute axisymmetric gasdynamic simulations of the two flows, and find that we do obtain large working surfaces at the positions of the HH 34S and HH 11 IV bow shocks for the time at which these objects are being observed. This appears to be quite definite proof that these bow shocks are indeed the result of an ejection velocity time-variability. Also, there is the observational fact that the HH 34S bow shock is huge, being wider than HH 11 IV by a factor of ∼3. We find that we can reproduce this difference in size by choosing an appropriate value for the density of the ambient medium. Finally, from our small sample of two reconstructed ejection velocity variability histories, we attempt to make some statements about the general nature of these variabilites, and their implications on the possible ejection/collimation mechanisms.
RESULTS OBTAINED BY MINIMISING NATURAL FREQUENCY AND MAC-VALUE ERRORS OF A PLATE MODEL

A plate model of the Garteur structure has been developed and updated. The cost function for the evaluation of the model's improvement consisted of residuals between calculated and measured natural frequencies and mode shapes. A brief description of the FE-model is followed by the presentation of the different modules used for the updating procedure, namely a substructure sensitivity analysis for parameter selection as well as an error localisation technique to detect modelling errors. The performance of the model is verified by different measured datasets, including data obtained by a modified structure.
Accretion disc viscosity: a simple model for a magnetic dynamo.

We develop here a simple physical model for the manner in which a magnetic dynamo might operate in an accretion disc and so provide an effective (magnetic) viscosity. In contrast to other dynamo models, the mechanism we discuss does not depend on the existence of some hydrodynamical small-scale turbulent flow hypothesized to be already present in a non-magnetic disc. Rather, the model we present depends on three well-established physical processes: the Parker instability, the Balbus-Hawley instability and magnetic field reconnection. The model gives rise to finite but non-stationary magnetic field configurations
Langmuir turbulence and ionospheric modification

Experimental results, obtained with the Heating facility and the EISCAT UHF and VHF radars at Tromso, Norway, have been used to test existing Langmuir turbulence theories and to provide further observational facts to be taken into account in a new theoretical formulation of Langmuir turbulence. It is found that none of the available theories is able to describe the diversity of observational facts. The dominance of propagating Langmuir and ion acoustic waves in the observed spectra, and the fact that these waves closely follow their linear dispersion relations, lend support to a weak turbulence description. On the other hand, the observation that the number of cascade steps is limited to two, independent of input power, strongly contradicts such an approach. Unmistakable indications for the occurrence of caviton collapse are not seen in the experimental results at Tromso. The low-frequency turbulence is found to consist of subsonic and sonic contributions, showing widely independent properties. The sonic turbulence is seen to evolve from the natural, thermally excited, ion acoustic background.
Dielectric and optical properties of dense plasmas

The interaction of matter with radiation concerns almost every area in physics. The exposure of matter to radiation may change its behavior. The focus of the present review are strongly correlated Coulomb systems under the influence of electromagnetic fields. Within linear response, the dynamical and non local (frequency and wave vector dependent) dielectric function and related quantities such as the polarization function and the response function, are expressed via equilibrium correlation functions. In particular, relations for the dynamical conductivity, the dynamical local field factor, the dynamical collision frequency and the dynamical structure factor are given with respect to current-current correlation functions and force-force correlation functions. Instead of a simple Drude formula which introduces a relaxation time in a semi-empiric way, a systematic quantum statistical approach is given which is able to describe the dynamical behavior of the collision frequency. The evaluation of correlation functions is performed within a systematic quantum statistical approach and compared to molecular dynamics simulations. The results obtained are of interest with respect to the production of radiation, the excitation of matter in electromagnetic fields, the diagnostics of matter etc. Applications to the dynamical conductivity, Bremsstrahlung, Thomson scattering and optical reflectivity are discussed.
Bistatic sonobuoy deployment strategies for detecting stationary and mobile underwater targets

The problem of determining effective allocation schemes of underwater sensors for surveillance, search, detection, and tracking purposes is a fundamental research area in military operations research. Among the various sensor types, multistatic sonobuoy systems are a promising development in submerged target detection systems. These systems consist of sources (active sensors) and receivers (passive sensors), which need not be collocated. A multistatic sonobuoy system consisting of a single source and receiver is called a bistatic system. The sensing zone of this fundamental system is defined by Cassini ovals. The unique properties and unusual geometrical profile of these ovals distinguish the bistatic sensor allocation problem from conventional sonar placement problems. This study is aimed at supporting decision makers in making the best use of bistatic sonobuoys to detect stationary and mobile targets transiting through an area of interest. We use integral geometry and geometric probability concepts to derive analytic expressions for the optimal source and receiver separation distances to maximize the detection probability of a submerged target. We corroborate our analytic results using Monte Carlo simulation. Our approach constitutes a valuable “back of the envelope” method for the important and difficult problem of analyzing bistatic sonar performance.
Numerical modeling of the radiation by a submerged fluid-filled cylindrical shell: Observation of the S0, A0, and A waves

We consider a submerged fluid-filled cylindrical shell subjected to an external acoustic pulse, and analyze the structure of the field radiated by the shell into the fluids, both external and internal. We first propose a computationally efficient semi-analytical model of the interaction based on the Reissner-Mindlin shell theory combining some of the classical methods of mathematical physics with the finite-difference methodology, and then use the model to simulate the interaction. We demonstrate that the model accurately reproduces the wave structure of the radiated fields seen in the experiments for submerged evacuated shells, namely both the symmetric Lamb waves S0 and the pseudo-Rayleigh waves A0. It is further observed that the internal and external wave patterns associated with the A0 waves exhibit the same alternation of the equiphase lines as the one seen in the experiments for a plate loaded by the fluid on both sides, a result that seems to be particularly relevant in the context of very limited.
Stable carbon and nitrogen isotopic composition of leaves, litter, and soils of various ecosystems along an elevational and land-use gradient at Mount Kilimanjaro, Tanzania

Abstract. Variations in the stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) of fresh leaves, litter, and topsoils were used to characterize soil organic matter dynamics of 12 tropical ecosystems in the Mount Kilimanjaro region, Tanzania. We studied a total of 60 sites distributed along five individual elevational transects (860–4550 m a.s.l.), which define a strong climatic and land-use gradient encompassing semi-natural and managed ecosystems. The combined effects of contrasting environmental conditions, vegetation, soil, and management practices had a strong impact on the δ13C and δ15N values observed in the different ecosystems. The relative abundance of C3 and C4 plants greatly determined the δ13C of a given ecosystem. In contrast, δ15N values were largely controlled by land-use intensification and climatic conditions. The large δ13C enrichment factors (δ13Clitter − δ13Csoil) and low soil C∕N ratios observed in managed and disturbed systems agree well with the notion of altered SOM dynamics. Besides the systematic removal of the plant biomass characteristic of agricultural systems, annual litterfall patterns may also explain the comparatively lower contents of C and N observed in the topsoils of these intensively managed sites. Both δ15N values and calculated δ15N-based enrichment factors (δ15Nlitter − δ15Nsoil) suggest the tightest nitrogen cycling at high-elevation (> 3000 m a.s.l.) ecosystems and more open nitrogen cycling both in grass-dominated and intensively managed cropping systems. However, claims about the nature of the N cycle (i.e. open or closed) should not be made solely on the basis of soil δ15N as other processes that barely discriminate against 15N (i.e. soil nitrate leaching) have been shown to be quite significant in Mount Kilimanjaro's forest ecosystems. The negative correlation of δ15N values with soil nitrogen content and the positive correlation with mean annual temperature suggest reduced mineralization rates and thus limited nitrogen availability, at least in high-elevation ecosystems. By contrast, intensively managed systems are characterized by lower soil nitrogen contents and warmer conditions, leading together with nitrogen fertilizer inputs to lower nitrogen retention and thus significantly higher soil δ15N values. A simple function driven by soil nitrogen content and mean annual temperature explained 68 % of the variability in soil δ15N values across all sites. Based on our results, we suggest that in addition to land-use intensification, increasing temperatures in a changing climate may promote soil carbon and nitrogen losses, thus altering the otherwise stable soil organic matter dynamics of Mount Kilimanjaro's forest ecosystems.
Spectral characteristics of zonal flows in the edge plasmas of the HT-7 tokamak

The spectral characteristics of zonal flows, including both the geodesic acoustic mode (GAM) and the zero/low frequency zonal flow (LFZF), are investigated by applying the two-point correlation technique and bispectral analysis to the floating potential fluctuations measured by several Langmuir probe arrays on the HT-7 tokamak. The three-dimensional wavenumber and frequency spectra for the two modes have been estimated. The radial wavenumber spectra show that the LFZF packages propagate both outward and inward while the GAM packages propagate outward mostly. Nonlinear couplings betweeen zonal flows and ambient turbulence are observed in the biphase while the bicoherence at the GAM frequency is much larger than that at the LFZF frequency. A kind of mode with frequencies higher than that of GAM, which may also be generated from the ambient turbulence in a similar way as the zonal flows, is reported.
Exploiting Rank Ordered Choice Set Data within the Stochastic Utility Model

The authors report on a procedure for exploiting the information content of rank ordered choice sets to estimate efficiently the parameters of the multinomial logit model formulation of the stochastic utility model of choice behavior. The availability of rank ordered choice set data leads to an “explosion” or decomposition procedure for exploiting such extra information. This “explosion” process involves the decomposition of a ranked choice set into a series of unranked and statistically independent choice sets. In relation to explosion strategies, several heuristics and an analytical procedure for determining the “optimal” explosion depth are discussed in detail. The results of a Monté Carlo study of the small sample properties of the conditional logit estimation procedure (the maximum likelihood estimation procedure used to develop parameter estimates of the multinomial logit model formulation of the stochastic utility model) are reported and interpreted. A college choice empirical application illustrates the procedures developed.
Coherent nonlinear scattering of energetic electrons in the process of whistler mode chorus generation

[1] Cyclotron resonant wave-particle interaction of whistler mode chorus emissions drives pitch angle scatterings of a wide range of energetic electrons in the magnetosphere. We study a coherent scattering process associated with generation of the whistler mode rising chorus emissions near the geomagnetic equator in a self-consistent electromagnetic full-particle simulation. The simulation shows that coherent whistler mode rising chorus emissions scatter energetic electrons very effectively through formation of an electromagnetic electron hole. The nonlinear interaction induces acceleration of resonant electrons trapped by the wave and deceleration of untrapped resonant electrons. When the frequency of a rising chorus element continuously increases in time from lower frequencies to higher frequencies, the parallel resonant velocity continuously decreases toward lower-velocity ranges resulting in significant scattering of resonant electrons. The lower limit of resonant parallel velocity is determined by the upper frequency limit of the rising chorus element. The unscattered electrons with low parallel velocities and the accelerated resonant electrons trapped by the wave result in the distribution clearly peaked at 90°. Successive generation of rising chorus elements can scatter resonant electrons in the same resonance velocity range. The repeated scatterings make the distribution much sharper at 90°, leading to formation of a pancake distribution function as observed in the inner magnetosphere.
Wave rectification in plasma sheaths surrounding electric field antennas

Combined measurements of Langmuir or broadband whistler wave intensity and lower-frequency electric field waveforms, all at 10-microsecond time resolution, were made on several recent sounding rockets in the auroral ionosphere. It is found that Langmuir and whistler waves are partically rectified in the plasma sheaths surrounding the payload and the spheres used as antennas. This sheath rectification occurs whenever the high frequency (HF) potential across the sheath becomes of the same order as the electron temperature or higher, for wave frequencies near or above the ion plasma frequency. This rectification can introduce false low-frequency waves into measurements of electric field spectra when strong high-frequency waves are present. Second harmonic signals are also generated, although at much lower levels. The effect occurs in many different plasma conditions, primarily producing false waves at frequencies that are low enough for the antenna coupling to the plasma to be resistive.
Full swing logic inverter with amorphous SiInZnO and GaInZnO thin film transistors

A high-performance n-channel metal-oxide-semiconductor inverter implemented consisting of enhancement mode driving thin-film transistor with amorphous Ga-In-Zn-O (a-GIZO) and depletion mode load with amorphous Si-In-Zn-O (a-SIZO) is demonstrated. The threshold voltage of the post-annealed a-SIZO load thin film transistor (TFT) exhibits negative value while the threshold voltage of the GIZO driving TFT exhibits positive value. The proposed inverter composed of a-SIZO and a-GIZO TFT shows much improved switching characteristics with higher voltage gain.
The Relationship between Overlying Synoptic-Scale Flows and Winds within a Valley

Abstract The relationship between winds above and within the Tennessee Valley is investigated climatologically and with an atmospheric numerical model. For the climatological analyses, winds above the valley were determined by interpolation from four surrounding rawinsonde stations, while winds within the valley were measured on four 100-m towers. Tennessee Valley winds are generally weak and bidirectional, oriented along the valley's axis. The valley wind direction depends strongly on the component of the synoptic-scale pressure gradient that is superimposed along the valley's axis at ridge-top level, with winds blowing along the valley's axis from high toward low pressure. This relationship between winds above and within the valley can result in countercurrents similar to those observed in the Rhine Valley. While winds in the Tennessee Valley are driven primarily by this pressure-driven channeling mechanism, downward momentum transport can cause afternoon winds within the valley to approach the wind dir.