Miracle-dz/UniFAR-FTUs huggingface dataset:
Nozzle flow with vibrational nonequilibrium

This research concerns the modeling and numerical solutions of the coupled system of compressible Navier-Stokes equations in cylindrical coordinates under conditions of equilibrium and nonequilibrium thermodynamics. The problem considered was the modeling of a high temperature diatomic gas N2 flowing through a converging-diverging high expansion nozzle. The problem was modeled in two ways. The first model uses a single temperature with variable specific heats as functions of this temperature. For the second model we assume that the various degrees of freedom all have a Boltzmann distribution and that there is a continuous redistribution of energy among the various degrees of freedom as the gas passes through the nozzle. Each degree of freedom is assumed to have its own temperature and, consequently, each system state can be characterized by these temperatures. This suggests that formulation of a second model with a vibrational degree of freedom along with a rotational-translation degree of freedom, each degree of freedom having its own temperature. Initially the vibrational degree of freedom is excited by heating the gas to a high temperature. As the high temperature gas passes through the nozzle throat there is a sudden drop in temperature along with a relaxation time for the vibrational degree of freedom to achieve equilibrium with the rotational-translation degree of freedom. That is, we assume that the temperature change upon passing through the throat is so great that the changes in the vibrational degree of freedom occur at a much slower pace and consequently lags behind the rotational-translational energy changes. This lag results in a finite relaxation time. In this context the term nonequilibrium is used to denote the fact that the energy content of the various degrees of freedom are characterized by two temperatures. We neglect any chemical reactions which could also add nonequilibrium effects. We develop the energy equations for the nonequilibrium model from first principles. The resulting equations, which model the nozzle flow, can be expressed in various forms. In most forms the resulting equations are coupled systems of nonlinear partial differential equations subject to certain boundary conditions. To solve the resulting coupled system of nonlinear partial differential equations, several numerical techniques were investigated: (1) the explicit MacCormack method, (2) the explicit-implicit MacCormack method, (3) the method of operator splitting, (4) factorization schemes, and (5) the Steger-Warming scheme.
Frequency dependence of Q for seismic body waves in the Earth's mantle

In this paper an attempt is made to determine the frequency dependence of Q in the Earth's mantle in the frequency range 0.03-1.5 Hz from the spectral ratio of teleseismic Sand P-waves. Digital broad-band data of 17 earthquakes at 40° <A < 90° recorded at the Central Seismological Observatory of the Federal Republic of Germany at Erlangen were analysed. The method implies the following assumptions: frequency independence of the crustal transfer function, proportionality of Qp(f) and Qs(f), and proportionality of Pand Ssource spectra. This last and most critical assumption was carefully investigated by kinematic and dynamic source models. The calculated Q-spectra for the individual events vary considerably but all have in common a general increasing trend with frequency which can best be represented by a power law Q,. , r with 0.25 < °' < 0.6. A further increase in slope near 1 Hz suggests an absorption band corner with an upper cut-off relaxation time •m = 0.33 ± 0.18 s; The significance of the Q-spectra and their variability is estimated by manipulating semi-synthetic seismograms with different error-producing processes such as length and shape of the time window, superposition of noise, digital filter process and source spectra. It is concluded that none of these processes is able to destroy or to imitate the observed increasing trend of Q with frequency. The results are compared with those from other seismological investigations and from laboratory experiments on mantle rocks at high temperature and in the seismic frequency band.
Asymptotic, multigroup flux reconstruction and consistent discontinuity factors

Recent theoretical work has led to an asymptotically derived expression for reconstructing the neutron flux from lattice functions and multigroup diffusion solutions. The leading-order asymptotic term is the standard expression for flux reconstruction, i.e., it is the product of a shape function, obtained through a lattice calculation, and the multigroup diffusion solution. The first-order asymptotic correction term is significant only where the gradient of the diffusion solution is not small. Inclusion of this first-order correction term can significantly improve the accuracy of the reconstructed flux. One may define discontinuity factors (DFs) to make certain angular moments of the reconstructed flux continuous across interfaces between assemblies in 1-D. Indeed, the standard assembly discontinuity factors make the zeroth moment (scalar flux) of the reconstructed flux continuous. The inclusion of the correction term in the flux reconstruction provides an additional degree of freedom that can be used to make two angular moments of the reconstructed flux continuous across interfaces by using current DFs in addition to flux DFs. Numerical results demonstrate that using flux and current DFs together can be more accurate than using only flux DFs, and that making the second angular moment continuous can be more accurate than making the zeroth moment continuous.
Numerical simulation of stably stratified flow over hills

The aim of the work described in this thesis is the development and application of a method to simulate computationally flows such as those investigated by Castro and Snyder [17], specifically flow over three-dimensional hills at high Reynolds and moderate to low obstacle Froude number. For hills elongated in the span wise direction, this flow regime is characterized by breaking lee waves and accelerated flow near the lower surface downstream of the obstacle. Simulations were performed by discretizing the three-dimensional Reynolds-averaged Navier-Stokes equations, and solving these numerically by a finite volume method. Buoyancy was modelled using the Boussinesq approximation, and modified k-e models employed for turbulence closure. The results obtained are found to be in reasonably good agreement with experimental flow visualizations. Critical Froude numbers for wave breaking are also found to be in reasonable agreement. Further, comparison is made with the nonlinear hydrostatic theory of Smith [101]; agreement is found to be fair, although the theory postulates a flow configuration differing from those observed in simulations. Also investigated were the effects of modifications to the turbulence model, Reynolds number, small departures from linear stratification, of wall, symmetry, and wave-permeable boundary conditions, and of the size of the computational domain. The last of these was found to affect the transient development of the flow, but to have only a weak effect on the steady state converged to, pending the arrival of reflected internal waves. Grid independence of the solution was investigated, and found to be satisfactory. One subsequent grid dependence test, however, yielded more equivocal results.
Caladan: Mitigating Interference at Microsecond Timescales

The conventional wisdom is that CPU resources such as cores, caches, and memory bandwidth must be partitioned to achieve performance isolation between tasks. Both the widespread availability of cache partitioning in modern CPUs and the recommended practice of pinning latency-sensitive applications to dedicated cores attest to this belief. In this paper, we show that resource partitioning is neither necessary nor sufficient. Many applications experience bursty request patterns or phased behavior, drastically changing the amount and type of resources they need. Unfortunately, partitioning-based systems fail to react quickly enough to keep up with these changes, resulting in extreme spikes in latency and lost opportunities to increase CPU utilization. Caladan is a new CPU scheduler that can achieve significantly better quality of service (tail latency, throughput, etc.) through a collection of control signals and policies that rely on fast core allocation instead of resource partitioning. Caladan consists of a centralized scheduler core that actively manages resource contention in the memory hierarchy and between hyperthreads, and a kernel module that bypasses the standard Linux Kernel scheduler to support microsecondscale monitoring and placement of tasks. When colocating memcached with a best-effort, garbage-collected workload, Caladan outperforms Parties, a state-of-the-art resource partitioning system, by 11,000×, reducing tail latency from 580 ms to 52 μs during shifts in resource usage while maintaining high CPU utilization.
Effect of Alkalized Phosphogypsum on Soil Chemical and Biological Properties

Phosphogypsum (PG) was mixed with calcium hydroxide [Ca(OH)2], ranging from 0 to 5%, to determine the optimal amount of Ca(OH)2 required to alkalize the acidity of PG. The alkalized PG by 4% of Ca(OH)2 addition was selected for field tests to evaluate the effects of alkalized PG on soil microbial, chemical properties, and yield of Chinese cabbage. Soil pH increased with increasing application rate of the alkalized PG and decreased with the unmodified PG application. Available phosphorus (P), water‐soluble sulfate (SO4 2−), and exchangeable potassium (K), calcium (Ca), and magnesium (Mg) increased significantly with increasing application rate of alkalized and unmodified PG. Microbial biomass carbon (C) and nitrogen (N) concentrations, soil enzyme activities, and the yield of Chinese cabbage in the alkalized PG application were greater than those of unmodified PG application. We concluded that alkalizing PG by mixing it with an alkaline material such as Ca(OH)2 can turn it into a useful material for agricultural utilization.
In Situ Scanning Tunneling Microscopy of a Redox Molecule as a Vibrationally Coherent Electronic Three-Level Process

We provide a theoretical frame for in situ scanning tunneling microscopy (STM) of adsorbate molecules with low-lying redox levels strongly coupled to the environmental nuclear motion. The STM process is viewed as a coherent two-step electron transfer (ET) involving electron exchange between the local redox level and the manifolds of electronic levels in the substrate and tip. The notion coherence is here taken to imply that the intermediate electron or hole state after the first ET step does not fully relax vibrationally before the second ET step. These views and the theoretical formalism are appropriate to in situ STM of large transition metal complexes and redox metalloproteins. The formalism offers two kinds of spectroscopic features. One is the relation between the tunnel current and the bias voltage at fixed overvoltage of either the tip or the substrate relative to a reference electrode. The other one is the tunnel current dependence on the overvoltage, at fixed bias voltage. Recent data on tunnelin.
A Study on Cochlear-implanted Children’s Early First Language Development

This study investigates the cochlear-implanted (CI) children’s early language development status. It mainly focuses on two perspectives: 1, whether and how would daily parent-child interaction influence CI children’s special belated first language (L1) acquisition; and 2, are there any similarity or differences between the L1 acquisition of CI children and children with normal hearing ability. The study recruited 16 young CI children (aged 3-8 years old), who were born with no hearing ability and received cochlear implantation in January to February 2018. In the beginning of the study, the participants’ parents were informed and consented to take several home video clips containing daily parent-child interactions. After 8 months of cochlear implantation, the participants were invited to participate in a language comprehension test. The results of a Pearson correlation coefficient show that, there is a significant positive correlation between the parent-driven efficient communication and participants’ test performance, while child-driven efficient communication does. This indicates that proper parenting methods have a significant positive influence on CI children’s language development, at least at the early stages. Meanwhile, participants’ language test performances showed higher correction rate in noun comprehension, moderate to low correction rate in adjective comprehension, and zero response to verbs. This implies an acquisition order of noun àadjective à verb, which is the same as standard L1 acquisition. However, the mean response time (RT) captured in their language tests is significantly longer than that of normal-hearing children within the same age range.
Fusing Structured Knowledge Priors for Named Entity Recognition

Information extraction (IE) aims to mine structured knowledge from large un/semi-structured data, and can further benefit the construction of various knowledge graphs, including Product Knowledge Graphs from Amazon [1]. Such structured knowledge graphs have huge potentials in downstream applications such as recommendation, question answering, etc. Our recent works also show that factual structures extracted from text corpora can serve as fundamental elements in constructing heterogeneous information networks [2], and facilitate several downstream applications such as recommender systems [3, 4], structured search and exploration of text data [5], and document summarization [6]. As new facts are constantly emerging, a key challenge in data science is to populate existing knowledge graphs through information extraction tasks including entity recognition, linking, relation extraction, etc. Deep learning has gained lots of success in applying to a variety of tasks in information extraction and natural language processing [7, 8, 9, 10, 11]. However, these end-to-end, data-hungry neural models suffer from limited performance when labeled training data are expensive to obtain or very noisy. Moreover, since representation learning in neural architectures operates on a subsymbolic level (e.g. by replacing words with embeddings), it is hard to determine why we obtain a certain prediction, let alone how to correct systematic errors or how to incorporate heuristic rules or domain knowledge. This prevents users from debugging and improving their IE systems in practice. Thus, how to develop interpretable neural architectures for information extraction tasks under weak supervision becomes an important direction. The above issues do not exist with purely symbolic, rule-based approaches for IE. They usually utilize external heuristic signals, such as human-crafted rules, heuristic patterns, and external knowledge bases, which we call structured knowledge priors. Symbolic rule-based systems are interpretable and easy to modify. They do not need large amounts of training data and we can easily incorporate structured priors. On the other hand, lacking representational power makes rulebased system not generalizable to unseen data (e.g. novel entities and relations). Consequently, we would like to propose methods that can take the best of both worlds (i.e. neural architectures and structured priors).
Direct fabrication of enzyme-carrying polymer nanofibers by electrospinning

Nanofibers consisting of enzyme–polymer composites have been prepared by directly electrospinning a solution of surfactant-stabilized enzyme and polymer in toluene. Additional treatment with glutaraldehyde could greatly stabilize the enzyme activity of the fibers, which could be maintained in a buffer under shaking conditions for more than two weeks. The nanofibers also showed great improvement in the enzyme activity over bulk films as a result of increased mass-transfer for substrate molecules to and from the enzyme reactive sites. These stable and catalytically active nanofiber-based mats were highly durable and could be easily recovered from solution, making them ideal candidates for large scale applications.
Atomic resonance fluorescence spectrometry for rate constants of rapid bimolecular reactions. Part 3.—Oxygen atom resonance O 3S1–3P2, 1, 0

Measurements at 298 K of the intensities of atomic resonance absorption and of atomic resonance fluorescence, as functions of ground state O 3PJ oxygen atom concentrations, have been made for each of the three transitions (near λ 130 nm) of the O 3S1–3P2,1,0 multiplet. The light source was an oxygen atom lamp in argon carrier gas, and O 3PJ oxygen atoms were generated in a discharge–flow system, both at low pressure (< 200 N m–2). Simple theory shows that the resonance absorption intensity, A=Iabs/I0, varies with optical depth in the absorber, k0l, (k0l∝[O 3PJ]), according to a polynomial, A=(k0l)α–½(k0l)2β+…, always leading to the limiting case A→(k0l)α as k0l→0. Several models for the line profile of the atomic resonance lamp are used to compute values for A and the coefficients α, β…, for comparison with the experimental values obtained for these parameters. The results are extended to include the case of Lorentz-broadened absorption lines, in order to relate absorption measurements in low-pressure flow systems to those in higher pressure experiments (e.g. pulsed photolysis studies). The intensity of resonance fluorescence IF at low pressure is considered as a function of the intensity of absorption from the source, and a fluorescence emission function. The effective absorption coefficient for O 3PJ atoms is much higher for the non-reversed fluorescent radiation emitted homogeneously in the fluorescence cell, than for the radiation originating from a typical (self-reversed) source. Consequently, the concentration of O 3PJ atoms can be low enough to be optically thin with respect to absorption of radiation from the source but high enough to be optically thick with respect to re-absorption of fluorescence emitted within the homogeneous mixture of emitters and absorbers in the fluorescence cell. These considerations are used to obtain an approximate model for the variation of IF with [O 3PJ]—as for absorption, the model leads to a polynomial in k0l with the same experimentally-observed limiting case IF→C′(k0l) as k0l→0.The results show that whilst the O 3S1–3P2(λ 130.2 nm) line is more sensitive than the O 3S1–3P0(λ 130.6 nm) line for the detection of O 3PJ atoms, the range of linear dependence of IF upon total oxygen atom concentration extends to much higher concentrations for λ 130.6 than for the λ 130.2 transition.
Carbon-doped symmetric GaAs∕AlGaAs quantum wells with hole mobilities beyond 106cm2∕Vs

Utilizing a carbon filament doping source, we prepared two-dimensional hole gases in a symmetric quantum-well structure in the GaAs∕AlGaAs heterosystem. Low-temperature hole mobilities up to 1.2×106cm2∕Vs at a density of 2.3×1011cm−2 were achieved on GaAs (001) substrates. In contrast to electron systems, the hole mobility sensitively depends on variations of the quantum-well width and the spacer thickness. In particular, an increase of the quantum-well width from an optimal value of 15 nm to 18 nm is accompanied by a 35% reduction of the hole mobility. The quality of ultrahigh-mobility electron systems is not affected by the employed carbon-doping source.Utilizing a carbon filament doping source, we prepared two-dimensional hole gases in a symmetric quantum-well structure in the GaAs∕AlGaAs heterosystem. Low-temperature hole mobilities up to 1.2×106cm2∕Vs at a density of 2.3×1011cm−2 were achieved on GaAs (001) substrates. In contrast to electron systems, the hole mobility sensitively depends on variations of the quantum-well width and the spacer thickness. In particular, an increase of the quantum-well width from an optimal value of 15 nm to 18 nm is accompanied by a 35% reduction of the hole mobility. The quality of ultrahigh-mobility electron systems is not affected by the employed carbon-doping source.
Stability of Small MgO Nanotube Clusters: Predictions of a Transferable Ionic Potential Model

The recently introduced compressible-ion interaction model (CIM) is extended to allow for coordination number-dependent oxide polarizabilities. The variable polarizability is parametrized from existing Hartree−Fock calculations. The resulting potential is used to examine small (MgO)n clusters in both their relaxed and unrelaxed (more symmetrical) structures. The results are compared to experimental results and both Hartree−Fock and density functional theory calculations. Comparison with alkali halide clusters is also made. The potential is found to be transferable over a wide range of ionic environments, spanning gas-phase clusters and the bulk phase. MgO nanotubes are found to be stable for small clusters of less than 30 molecules.
Rotational spectra of 20NeH+, 20NeD+, 22NeH+, and 22NeD+

Rotational transitions of 20NeH+, 20NeD+, 22NeH+, and 22NeD+ were observed in the 1–5 THz frequency region with a high-precision far-infrared spectrometer using a tunable radiation source. Observed frequencies were incorporated with previous infrared measurement to redetermine Dunham coefficients Ykl and isotopically independent parameters Ukl, ΔklH, and ΔklNe, where Δ02H and Δ01Ne were determined for the first time.
Main-chain PPEGMEMA-b-PBTFVPP-b-PPEGMEMA perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymer: synthesis and self-assembly

A series of perfluorocyclobutyl aryl ether-based amphiphilic ABA triblock copolymers consisting of hydrophilic poly[poly(ethylene glycol) methyl ether methacrylate] (PPEGMEMA) and hydrophobic poly(2,2′-bis(4-trifluorovinyl-oxyphenyl)propane) (PBTFVPP) blocks were synthesized via the site transformation strategy. A semi-fluorinated PBTFVPP segment was first prepared via thermal step-growth cycloaddition polymerization of BTFVPP trifluorovinyl aryl ether monomer followed by end functionalization to be transformed into Br–PBTFVBP–Br macroinitiator bearing one ATRP initiating group at each end. The target PPEGMEMA-b-PBTFVPP-b-PPEGMEMA triblock copolymers with relatively narrow molecular weight distributions (Mw/Mn ≤ 1.32) were synthesized via ATRP of PEGMEMA macromonomer initiated by Br–PBTFVBP–Br macroinitiator. A fluorescent probe technique was used to determine the critical micelle concentrations (cmc) of the obtained amphiphilic copolymers in aqueous solution. The morphologies of the micelles formed by the copolymers were investigated by transmission electron microscopy. It was shown that such triblock copolymers could self-assemble into ovals, well-defined cylinders, and spheres in aqueous solution with different initial water contents and compositions.