Oscillation criteria for third-order neutral differential equations with continuously distributed delay

AbstractThe purpose of this paper is to study the oscillation of a certain class of third-order neutral differential equations with continuously distributed delay. By using a generalized Riccati transformation and integral averaging technique, we establish some new sufficient conditions which ensure that every solution of this equation oscillates or converges to zero

Developing an Enhanced Short-Range Railroad Track Condition Prediction Model for Optimal Maintenance Scheduling

As railroad infrastructure becomes older and older and rail transportation is developing towards higher speed and heavier axle, the risk to safe rail transport and the expenses for railroad maintenance are increasing. The railroad infrastructure deterioration (prediction) model is vital to reducing the risk and the expenses. A short-range track condition prediction method was developed in our previous research on railroad track deterioration analysis. It is intended to provide track maintenance managers with two or three months of track condition in advance to schedule track maintenance activities more smartly. Recent comparison analyses on track geometrical exceptions calculated from track condition measured with track geometry cars and those predicted by the method showed that the method fails to provide reliable condition for some analysis sections. This paper presented the enhancement to the method. One year of track geometry data for the Jiulong-Beijing railroad from track geometry cars was used to conduct error analyses and comparison analyses. Analysis results imply that the enhanced model is robust to make reliable predictions. Our in-process work on applying those predicted conditions for optimal track maintenance scheduling is discussed in brief as well

New Oscillatory Behavior of Third-Order Nonlinear Delay Dynamic Equations on Time Scales

A class of third-order nonlinear delay dynamic equations on time scales is studied. By using the generalized Riccati transformation and the inequality technique, four new sufficient conditions which ensure that every solution is oscillatory or converges to zero are established. The results obtained essentially improve earlier ones. Some examples are considered to illustrate the main results

Observation of the 5p Rydberg states of sulfur difluoride radical by resonance-enhanced multiphoton ionization spectroscopy

Sulfur difluoride radicals in their ground state have been produced by a "laser-free" pulsed dc discharge of the SF$_{6}$/Ar gas mixtures in a supersonic molecular beam and detected by mass-selective resonance-enhanced multilphoton ionization (REMPI) spectroscopy in the wavelength range of 408 - 420 nm. Analyses of the (3 + 1) REMPI excitation spectrum have enabled identification of three hitherto unknown Rydberg states of this radical. Following the Rydberg state labeling in our previous work [see J. Phys. Chem. A 102, 7233 (1998)], these we label the K(5p$_{1}$) [$nu_{0-0}$ = 71 837 cm$^{-1}$, $omega_{1}^{'}$(a$_{1}$ sym str) = 915 cm$^{-1}$], L(5p$_{2}$) [$nu_{0-0}$ = 72 134 cm$^{-1}$, $omega_{1}^{'}$(a$_{1}$ sym str) = 912 cm$^{-1}$], and M(5p$_{3}$) [$nu_{0-0}$ = 72 336 cm$^{-1}$, $omega_{1}^{'}$(a$_{1}$ sym str) = 926 cm$^{-1}$] Rydberg states, respectively. [Origins, relative to the lowest vibrational level of the X$^{1}$A$_{1}$ ground state, and vibrational frequencies of the symmetric S-F stretching mode are suggested by the numbers in brackets.] Photofragmentation process of SF$_{2}$$^{+}$--SF$^{+}$ + F that relates to the REMPI spectrum was discussed.Comment: 17 pages, 1 table, 2 figure

Performance of several simple, noninvasive models for assessing significant liver fibrosis in patients with chronic hepatitis B

Aim To compare the performance of several simple, noninvasive models comprising various serum markers in diagnosing significant liver fibrosis in the same sample of patients with chronic hepatitis B (CHB) with the same judgment standard. Methods A total of 308 patients with CHB who had undergone liver biopsy, laboratory tests, and liver stiffness measurement (LSM) at the Southwest Hospital, Chongqing, China between March 2010 and April 2014 were retrospectively studied. Receiver operating characteristic (ROC) curves and area under ROC curves (AUROCs) were used to analyze the results of the models, which incorporated ageplatelet (PLT) index (API model), aspartate transaminase (AST) to alanine aminotransferase (ALT) ratio (AAR model), AST to PLT ratio index (APRI model), γ-glutamyl transpeptidase (GGT) to PLT ratio index (GPRI model), GGT-PLT-albumin index (S index model), age-AST-PLT-ALT index (FIB-4 model), and age-AST-PLT-ALT-international normalized ratio index (Fibro-Q model). Results The AUROCs of the S index, GPRI, FIB-4, APRI, API, Fibro-Q, AAR, and LSM for predicting significant liver fibrosis were 0.726 (P < 0.001), 0.726 (P < 0.001), 0.621 (P = 0.001), 0.619 (P = 0.001), 0.580 (P = 0.033), 0.569 (P = 0.066), 0.495 (P = 0.886), and 0.757 (P < 0.001), respectively. The S index and GPRI had the highest correlation with histopathological scores (r = 0.373, P < 0.001; r = 0.372, P < 0.001, respectively) and LSM values (r = 0.516, P < 0.001; r = 0.513, P < 0.001, respectively). When LSM was combined with S index and GPRI, the AUROCs were 0.753 (P < 0.001) and 0.746 (P < 0.001), respectively. Conclusion S index and GPRI had the best diagnostic performance for significant liver fibrosis and were robust predictors of significant liver fibrosis in patients with CHB for whom transient elastography was unavailable

Importance of Taking Into Account the Soil Stratification in Reproducing the Late-Time Features of Distant Fields Radiated by Lightning

In this paper, we present an analysis of the propagation effect along a lossy ground on the characteristics of lightning-generated electric fields, using simultaneous observations of lightning currents and radiated fields measured at nine different distances associated with rocket-triggered lightning. The triggered-lightning site is located inConghua (Guangdong,China). The electric field waveforms were measured using the sensors belonging to the Foshan three-dimensional lightning location system that are located at distances from the triggered-lightning site ranging from 69 to 126 km. The propagation path was over land and mainly over flat ground. The field sensors used had an overall bandwidth from 160 Hz to 1MHz. It is shown that even though the early response of the field can be reproduced reasonably well by adjusting the ground electrical conductivity, the subsidiary peaks, and the late-time response of the fields cannot be satisfactorily reproduced assuming a homogeneous ground model. However, a two-layer soil model allows obtaining very good agreement between computed and measured waveforms for all the considered distances and events. Compared to the homogeneous ground case, the computed early-, intermediate-, and late-time response follows to a much better extent the experimental waveforms. We also provide a discussion on the influence of the computational model and parameters on the simulated results

Research on rotary geosteering drilling technology and equipment in underground coal mine

In view of the limitations of directional drilling technology and equipment for underground gas drainage in coal mining areas, such as low degree of automation, low drilling ratio of target formation, slow drilling rate of rock formation, and small diameter, the research of rotary geosteering drilling technology and equipment underground coal mine has been carried out, with the core technical problems has overcame such as wireless remote control operation of directional drilling rigs, mechanically automatic drill pipe addition, real-time parameter monitoring and fault diagnosis, coal and rock identification while drilling, and trajectory rotation control, ZDY25000LDK electro-hydraulic controlled directional drilling rig, BLY800/12 mud pump truck with high-pressure and large-volume, YSG(A) Mine geosteering MWD system by dynamic azimuth gamma, ϕ133 mm hydraulic push type rotary steering drilling system and supporting drilling tools have developed, with the maximum torque was 25 000 N·m, the automatically add drill pipe time was less than 55s of the directional drilling rig, the rated flow was 800 L/min of the mud pump truck, the natural gamma measurement error was less than ±5% and the stratum exploration distance was ≥0.5 m of the geosteering MWD system, the applicable speed range was 80−200 r/min and the deflection force was 1.4 t of the rotary steerable drilling system; geosteering drilling technology and rotary steerable drilling technology for near horizontal hole has developed with the technical characteristics and process flow are introduced in detail. The field test was carried out in Tangjiahui Coal Mine in Inner Mongolia. 4 directional drillings were completed, with the maximum drilling depth was 820 m, the total footage was 2 419 m, the directional drilling diameter was 172 mm, the drilling efficiency was increased 25% in coal seam and 30% in rock, which realized the directional drilling from “geometric steering” to “rotary geosteering” underground coal mine, the intelligent level and drilling trajectory quality of underground directional drilling in coal mine has been improved, and provided technical equipment support for efficient underground gas drainage and intelligent mine construction

Calorimetric evidence for two phase transitions in Ba1−xKxFe2As2 with fermion pairing and quadrupling states

Materials that break multiple symmetries allow the formation of four-fermion condensates above the superconducting critical temperature (T c). Such states can be stabilized by phase fluctuations. Recently, a fermionic quadrupling condensate that breaks the Z 2 time-reversal symmetry was reported in Ba1−xKxFe2As2. A phase transition to the new state of matter should be accompanied by a specific heat anomaly at the critical temperature where Z 2 time-reversal symmetry is broken (TcZ2>Tc). Here, we report on detecting two anomalies in the specific heat of Ba1−xKxFe2As2 at zero magnetic field. The anomaly at the higher temperature is accompanied by the appearance of a spontaneous Nernst effect, indicating the breakdown of Z 2 symmetry. The second anomaly at the lower temperature coincides with the transition to a zero-resistance state, indicating the onset of superconductivity. Our data provide the first example of the appearance of a specific heat anomaly above the superconducting phase transition associated with the broken time-reversal symmetry due to the formation of the novel fermion order

Low-Cost Flexible Nano-Sulfide/Carbon Composite Counter Electrode for Quantum-Dot-Sensitized Solar Cell

Cu2S nanocrystal particles were in situ deposited on graphite paper to prepare nano-sulfide/carbon composite counter electrode for CdS/CdSe quantum-dot-sensitized solar cell (QDSC). By optimization of deposition time, photovoltaic conversion efficiency up to 3.08% was obtained. In the meantime, this composite counter electrode was superior to the commonly used Pt, Au and carbon counter electrodes. Electrochemical impedance spectra further confirmed that low charge transfer resistance at counter electrode/electrolyte interface was responsible for this, implied the potential application of this composite counter electrode in high-efficiency QDSC