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Quantum time-dependent wave-packet calculations have been carried out to explore the state-to-state dynamics of the ion–molecule (H−(D−),HD) collisions on two accurate ab initio potential energy surfaces in the collision energy range 0.2–1.2 eV. Total and final state-resolved integral and differential cross sections are elaborated in detail. The differential cross sections vary substantially with the collision energy, turning from predominantly backward-scattering at low collision energies to forward and sideways scattering bias at relatively high collision energies. The rebound, stripping and time-delayed mechanisms are found to be possible in (H−(D−),HD) collisions. A set of quasi-classical trajectory calculations were performed, and the results indicate that the backward-scattering peak is caused by the low impact parameter trajectories, while the trajectories of high impact parameter are responsible for the forward scattering. A set of representative state-to-state differential cross sections at collision energies 0.6 and 1.2 eV are also presented. Different reaction mechanisms are dominant in (H−(D−),HD) collisions at different collision energies, resulting in different product rovibrational state distributions. The differences between the dynamics results based on the two potential energy surfaces are also discussed. [ABSTRACT FROM AUTHOR]

The warmer-than-present (5–10 °C) climate during the Miocene Climate Optimum (MMCO, approximately 16.9–14.7 Ma) is likely to serve as a reference for future pessimistic warming scenarios. Forced with MMCO boundary conditions, the warming and ocean circulation changes are simulated by the fully coupled climate model FGOALS-g3 with a nominal 1° horizontal resolution ocean component model. Under a 400 ppmv CO 2 concentration, the model generally simulates the MMCO temperature well with small biases at mid and low latitudes compared to the proxy data. Large biases at high latitudes show that FGOALS-g3 fails to reproduce the weak meridional gradient indicated by the proxy record. MMCO surface albedo decreases significantly owing to changes in worldwide forest cover in the boundary condition and the amount of sea ice melt due to the warming climate compared with the PI run. Based on the Energy Balance Model decomposition, warming by the lower surface albedo reaches 1.4–2.7 °C, which is comparable to greenhouse effect warming (∼2.7 °C). Accompanied by MMCO global ocean warming and land–sea distribution changes, both oceanic wind-driven and thermohaline circulations strengthen. The Antarctic Circumpolar Current in the MMCO is stronger due to the enhanced westerly wind stress and the reduced sea ice extent. The intensified MMCO Atlantic Meridional Overturning Cell (AMOC) relative to PI is likely linked to the altered ocean-gateway configuration, particularly at low and middle latitudes. When the MMCO Panama Seaway and Tethys Seaway open, waters from the Pacific and the Indian Ocean converge and mix in the western North Atlantic. Combined with the supplemental water (∼30 Sv), the Gulf Stream is enhanced and flows more poleward, causing the sea ice to retreat, leading to a deeper mixed layer. Consequently, the Subpolar North Atlantic salinification causes stronger convective motion and the appearance of the Atlantic Meridional Overturning Cell. • The model simulates the reconstructed MMCO temperature well in low and mid latitudes. • Intensified greenhouse effect and low surface albedo mainly cause MMCO warmth. • Strengthened AMOC results from the convergence of Pacific and Indian Ocean water. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) generation and emission from No. 3 wastewater treatment plant (WWTP) in Xi’an (Orbal oxidation ditch) and No. 4 WWTP in Xi’an (reversed A/A/O) were measured throughout a year following the water environment research foundation protocol. The N2O generation and emission rates of No. 4 WWTP (generation rate of 14.43 kg (N2O)/d and emission rate of 13.78 kg (N2O)/d) were about twice that of No. 3 WWTP (generation rate of 7.09 kg (N2O)/d and emission rate of 6.52 kg (N2O)/d). The N2O emission factor of No. 4 WWTP (54.64 mg (N2O)/m3INF) was about 1.7 times that of No. 3 WWTP (36.20 mg (N2O)/m3INF). The ammonia oxidation rate, nitrite oxidation rate, and nitrous oxide generation rate were also measured. Results showed that the key factors of N2O generation and emission were the microbial population and aeration strategy. [ABSTRACT FROM PUBLISHER]

Six low-lying states ( X 2 Σ g + , A 2 Π u , B 2 Σ u + , 4 Σ g + , 4 Π u and 4 Σ u + ) of C 2 − anion are studied by highly correlated ab initio calculations. The potential energy curves (PECs) are computed in the internuclear separation from 0.8 to 5.0 Å using the complete active space self-consistent field method, and then performing the internally contracted multireference configuration interaction with Davidson correction. Core–valence correlation and scalar relativistic effect are considered through employing the aug-cc-pcV5Z-dk basis set. The spin–orbit coupling of the A 2 Π u state is also calculated using Breit–Pauli Hamiltonian. Based on the PECs derived from the high-level ab initio calculations, the spectroscopic parameters are obtained by fitting the ro-vibrational levels that are acquired by solving the ro-vibrational Schrödinger equation. These spectroscopic parameters, especially for low-lying doublet states, are in good agreement with the previously calculated and experimental results. Finally, the electronic transition dipole moment matrix elements, Franck–Condon factors, radiative lifetimes and oscillator strengths of A 2 Π u – X 2 Σ g + and B 2 Σ u + - X 2 Σ g + are calculated and discussed as well. [ABSTRACT FROM AUTHOR]

"Velocity-attitude matrix" matching method is proposed as a new approach to transfer alignment, in allusion to the disadvantages of "velocity-attitude" method which has a huge computation and low robustness, and "angular rate-acceleration" method which has a difficulty to compensate the lever-arm effect, and then an alignment model is deduced. Simulation results show that this method can complete a high precision alignment process and achieve a high precision, even if carrier aircraft do simple Angle maneuver. With the development tendency of SINS (strap-down inertial navigation system) as both master INS and slave INS, the characteristics of mathematics platform in SINS will make "velocity-attitude matrix" method used more and more widely. [ABSTRACT FROM AUTHOR]

Both the software and hardware of a pulsed eddy current (PEC) real-time testing device are designed to pre-process the noise from continuous casting slabs (CCS) during in situ defect detection. An algorithm based on a sliding window with a fixed length is developed in the process of denoising. The root mean square error (RMSE) and the signal-to- noise ratio (SNR) of the denoised PEC response are given with the combination of Daubechies4, Symlet4 and three threshold denoising algorithms. The results of the simulation and experiment indicate that the best real-time denoising condition is with the wavelet transform of three or four layers. Herein, the SNR obtained is above 19 dB and the average throughput rate is 51 kHz when the moving speed of the casting slabs is about 2 m/s. Our system highlights real-time processing, stability, high accuracy and strong anti-interference, so it is suitable for automatic testing in a production situation. [ABSTRACT FROM AUTHOR]

Highlights • The sensor utilized a DFB laser around 2.33 μm as source. • The sensor was developed by using a high performance microcontroller and simple DLIA algorithm. • The LoD of 0.45 ppm is achieved while a precision of 0.0875 ppm is observed with an optimal time of ∼24 s. • The response times were significantly shorted with the detectable threshold being set at 5 ppm instead of 100 ppm. Abstract A distributed feedback laser-based carbon monoxide (CO) sensor has been developed for early warning detection of fire. The sensor, based on a system-on-chip with high-performance 32-bit microcontroller (MCU), features a digital lock-in amplifier (DLIA) for wavelength modulation spectroscopy (WMS) to improve detection sensitivity. The ramp scanning signal and a sinusoidally modulated signal were generated and superimposed by the MCU, and converted by a digital-to-analog converter to scan the absorption line of CO around 2.327 μm. The n -harmonic components obtained through multiplication of the n- th cosine wave data of the spectral signal, were then processed by integration and filter algorithms. The Allan-Werle deviation was used to evaluate the long-term performance of the sensor. The limit of detection (LoD) for CO was calculated to be 0.0875 ppm based on an optimal integration time of ∼24 s. In field tests, five small-scale standard fires were investigated in accord with EN54 and the results for the test substances – cotton rope (smoldering fire), polyurethane foam (smoldering fire), beech wood, a sheet of A4 paper and polyvinylchloride – verified the reliability and robustness of the developed sensor. Relatively fast response times (110 s for foam and A4 paper; 250 s for PVC, beech wood and cotton rope) were realized based on a threshold of 5 ppm CO. The CO sensor is considered suitable for integration into portable devices for industrial application, particularly for in-situ early warning fire detection. [ABSTRACT FROM AUTHOR]

A resolved line pair was selected for simultaneous measurement of carbon monoxide (CO) and carbon dioxide (CO2) in the near-infrared (NIR) region. The spectral lines of CO and CO2 at 1.578 µm were measured by wavelength modulation spectroscopy (WMS)-2f and the absorption was enhanced with a multipass absorption cell. The white noise was further reduced by averaging technology. The detection sensitivity (1σ) for the system is estimated at 2.63 × 10−7 cm−1 for direct absorption spectroscopy. The ultimate detection limits of CO2 and CO mixed with pure N2 at 75 Torr are 29 parts per million (ppm) and 47 ppm, respectively. It is demonstrated that the signal is highly linear with the concentration in the range of 100–800 ppm. Based on an Allan variation analysis, the minimum detectable limit of CO2 and CO is 7.5 and 14 ppm, respectively. The response time of the system is about 30 s and a relationship of temperature dependence was obtained. As an example, an in situ measurement of exhaust of alkane combustion emission is presented. [ABSTRACT FROM AUTHOR]

Based on the non-Kolmogorov spectrum, using the extended Huygens–Fresnel principle, the analytical expressions for the spectrum of the coherent and incoherent superpositions of rectangular array Gaussian Schell-model (RAGSM) beams propagating through non-Kolmogorov atmospheric turbulence are derived, and are used to study the influence of non-Kolmogorov atmospheric turbulence on spectral changes of coherent and incoherent superpositions RAGSM beams. It is shown that, with the increment of the general exponent α and the inner scale of turbulence l 0 , as well as the decrement of the general structure constant C ˜ n 2 , the magnitude of the spectral shift will increase, the magnitude of spectral transition will decrease and the critical position of spectral transition will decrease. The outer scale of turbulence L 0 has little effect on the spectral shift and spectral transition. [ABSTRACT FROM AUTHOR]

Abstract: The spectra of d 3Δ–a 3П (7,1) band of CS radical were measured by optical heterodyne–concentration modulation spectroscopy in the region from 11640 to 12230cm−1. In total, we assigned three hundred and four lines, of which Ree and Rff branches in the d 3Δ1–a 3П0 subsystem and more than a hundred lines were first observed and identified. The anomalous lambda-doubling of the d 3Δ1 (υ =7) level reveals a local perturbation interaction from the 1Σ− state. The perturbation parameter between 1Σ− and a 3П0 (υ =13), and molecular constants of the d 3Δ1 (υ =7) as well as 1Σ− were derived through fitting all assigned lines to the effective Hamiltonian. [Copyright &y& Elsevier]

A laser-based spectrometer with a physical size of 60× 30 ×25 cm3 has been developed to continuously monitor CO and CH 4 in atmosphere based on tunable diode laser absorption spectroscopy (TDLAS). Two neighboring lines of CO and CH 4 around 2.3 μ m were selected as candidates for simultaneous measurement by a single diode distributed feedback (DFB) laser. A special Herriott-type multipass absorption cell, with a 72 m optical path length, was designed and used to enhance the absorption signals of sample gases. Normalized wavelength modulation spectroscopy was applied to improve the sensitivity and robustness of the spectrometer and it was implemented on a home-made electronic system based on field programmable gate array (FPGA). Meanwhile, the electronic system controlled the temperature and current of DFB laser with the precision of 0.01 °C and 40 ppm. The 2nd-harmonic signals normalized by the corresponding 1st-harmonic signals for both CO and CH 4 are of high linear response to their concentrations in the range of 0.046–4.6 ppm and 0.487–48.7 ppm, respectively. According to the Allan variance, respective minimum detection limits for CO and CH 4 are 0.73 ppb and 36 ppb at 122 s and 137 s. As an application example, the spectrometer has been validated through real-time and in-situ measurement of atmospheric CO and CH 4 for 48 h. Unlabelled Image • A compact laser-based spectrometer has been developed to monitor atmospheric CO and CH 4 using a single DFB laser emitting at 2.33 μm. • A special Herriott-type multipass cell combined with FPGA system was designed and used to improve the sensitivity and compactness of the system. • The normalized WMS-(2 f /1 f) technique was employed to achieve high robustness of spectrometer. • The spectrometer has been validated for real-time and in-situ measurement of atmospheric CO and CH 4 for 48 h. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to develop and validate a prediction model for premature circuit clotting of continuous renal replacement therapy (CRRT) in critically ill patients., Design: A retrospective cohort study was conducted on ICU patients undergoing CRRT. The Medical Information Mart for Intensive Care-III Clinical Database CareVue subset and Medical Information Mart for Intensive Care-IV were utilized for model development, while the eICU Collaborative Research Database was employed for external validation. Predictive factors were selected through Least Absolute Shrinkage and Selection Operator Regression and univariate logistic regression. A prediction model was then developed using binary logistic regression. Internal and external validations assessed the model's discrimination, calibration, and clinical net benefit., Results: This study encompassed 2531 patients overall, with a premature circuit clotting rate of 31.88 %. The prediction model comprises five variables: body temperature, anticoagulation, mean arterial pressure, maximum transmembrane pressure change within two hours, and vasopressor. The model demonstrated robust predictive performance, achieving an area under the receiver operating characteristic curve of 0.897 (95 % CI: 0.879-0.915) in the training set and 0.877 (95 % CI: 0.852-0.902) in the external validation set. Internal validation yielded a Brier score of 0.087, while external validation showed a Brier score of 0.120. Calibration curves indicated good model calibration for both validations. The decision curve analysis indicates that the model yields a clinical net benefit across a wide range of decision thresholds., Conclusion: The model demonstrates robust discrimination, calibration, and clinical net benefit, with readily available variables indicating substantial potential for valuable clinical applications., Implications for Clinical Practice: Healthcare providers in the ICU can leverage the model to evaluate the risk of premature circuit clotting in critically ill patients undergoing continuous renal replacement therapy, facilitating timely intervention to mitigate its incidence., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The aim of the present study was to explore the association between anemia and the risks and outcomes of diabetic foot (DF) in patients with type 2 diabetes mellitus (T2DM). A total of 145 patients with T2DM were recruited between January and December 2021 and divided into the DF and non-DF groups according to whether they were diagnosed with DF. Individual patient data were extracted and blood samples were evaluated in a biochemical center for routine biochemical and blood-related indicators. The patients' survival rates were followed up until December 2022. An independent-samples t-test and χ 2 test were used to compare the differences between the two groups. The association between the various clinical indicators for the DF and non-DF groups was evaluated using single-factor binary logistic regression analysis. Multi-factor binary logistic regression analysis was used to analyze the association between hemoglobin (Hb) and the risk for DF. A Kaplan-Meier survival curve was used to analyze the impact of anemia and DF on the 1-year survival rate. The diabetes duration, number of patients who smoked and consumed alcohol, and serum creatinine and C-reactive protein levels in the DF group were significantly higher than those in the non-DF group (P<0.05). By contrast, the estimated glomerular filtration rate (eGFR) and Hb, albumin (Alb) and total cholesterol levels, were lower in the DF group when compared with those in the non-DF group (P<0.05). All of the study participants were divided into two groups, according to their baseline eGFR [eGFR ≥90 or <90 ml/(min x 1.73 m²)]. It was found that, independently of renal function, lower Hb and Alb levels were associated with a higher incidence of DF. The 1-year survival rate for DF with anemia was significantly lower when compared with that in patients with DF without anemia (P<0.05). In conclusion, the Hb level in patients with T2DM is a protective factor against DF and anemia is an independent risk factor for DF. The present study suggested that anemia is associated with a decrease in the survival rate of patients with DF. This finding provided a theoretical basis for the clinical correction of anemia and improvement of DF prognosis (clinical trial no. 20220003)., Competing Interests: The authors declare that they have no competing interests., (Copyright © 2020, Spandidos Publications.)

Quantum time-dependent wave-packet calculations have been carried out to explore the state-to-state dynamics of the ion-molecule (H-(D-),HD) collisions on two accurate ab initio potential energy surfaces in the collision energy range 0.2-1.2 eV. Total and final state-resolved integral and differential cross sections are elaborated in detail. The differential cross sections vary substantially with the collision energy, turning from predominantly backward-scattering at low collision energies to forward and sideways scattering bias at relatively high collision energies. The rebound, stripping and time-delayed mechanisms are found to be possible in (H-(D-),HD) collisions. A set of quasi-classical trajectory calculations were performed, and the results indicate that the backward-scattering peak is caused by the low impact parameter trajectories, while the trajectories of high impact parameter are responsible for the forward scattering. A set of representative state-to-state differential cross sections at collision energies 0.6 and 1.2 eV are also presented. Different reaction mechanisms are dominant in (H-(D-),HD) collisions at different collision energies, resulting in different product rovibrational state distributions. The differences between the dynamics results based on the two potential energy surfaces are also discussed.

We report a multi-pass tunable diode laser absorption spectrometer based on the frequency-modulation spectroscopy (FMS) technique. It has the advantage of high scan speed and is immune to the etalon effect. A multi-pass Herriott-type cell was used in the spectrometer to increase the effective optical length to 17.5 m and compact the physical dimensions of the spectrometer to 60×30×30 cm 3 . Noise due to low-frequency fluctuation of the laser power and the 1/f noise in the rapid detection are sufficiently reduced by FMS. Interference fringes are effectively suppressed when the modulation frequency equals to integer or half-integer times of their free spectral range (FSR). An absorption line of C 2 H 2 around 1.51 µm was recorded with the spectrometer to demonstrate its capabilities. The response frequency of the spectrometer is up to 100 kHz (10 µs) thanks to the high modulation frequency of FMS. The detection sensitivity of the spectrometer is about 240 ppb (3σ) at 100 kHz measurement repetition rate. The amplitude of the absorption signal is highly linear to the C 2 H 2 concentration in the range of 300 ppb -100 ppm. Based on the Allan variation, the detection limit was determined to be 18 ppb with a detection time of 166 s.

A low-noise, low power, high modulation-bandwidth design integrated laser current and temperature driver with excellent long-term stability is described. The current driver circuit is based on the Hall-Libbrecht design. A high sensitivity and a stable driver current were obtained using a differential amplifier and an integral amplifier. The set-point voltage for the current driver came from an ultra-compact, ultra-low temperature coefficient voltage reference chip or the digital to analog convertor output of a microcontroller or a modulation signal. An integral temperature chip, referred to as ADN8834, was used to drive the thermoelectric cooler controller of the distributed feedback (DFB) laser. The internal amplifier acquired the feedback current of the temperature sensor. The proportional-integral-derivative parameters such as proportion, integration, and derivative were set by external resistors. The short- and long-term stability and linearity of the developed laser driver were tested using a DFB laser with a central wavelength of 6991 cm -1 . The laser driver was validated for high-sensitivity gas sensing of CO 2 and C 2 H 2 via a laser absorption spectroscopy experiment. The limits of detection were less than 11.5 ppm and 0.124 ppm for CO 2 and C 2 H 2 , respectively. Direct absorption measurements and the 1- f and 2- f demodulation signals confirmed the capabilities of the proposed laser driver system in high-sensitivity gas sensing applications. The driver unit can readily be accommodated into many portable laser sensing devices for industrial applications.

A resolved line pair was selected for simultaneous measurement of carbon monoxide (CO) and carbon dioxide (CO 2 ) in the near-infrared (NIR) region. The spectral lines of CO and CO 2 at 1.578 µm were measured by wavelength modulation spectroscopy (WMS)-2 f and the absorption was enhanced with a multipass absorption cell. The white noise was further reduced by averaging technology. The detection sensitivity (1σ) for the system is estimated at 2.63 × 10 -7  cm -1 for direct absorption spectroscopy. The ultimate detection limits of CO 2 and CO mixed with pure N 2 at 75 Torr are 29 parts per million (ppm) and 47 ppm, respectively. It is demonstrated that the signal is highly linear with the concentration in the range of 100-800 ppm. Based on an Allan variation analysis, the minimum detectable limit of CO 2 and CO is 7.5 and 14 ppm, respectively. The response time of the system is about 30 s and a relationship of temperature dependence was obtained. As an example, an in situ measurement of exhaust of alkane combustion emission is presented.

Wavelength modulation spectroscopy (WMS) combined with a multipass absorption cell has been used to measure a weak absorption line of carbon monoxide (CO) at 1.578 µm. A 0.95m Herriott-type cell provides an effective absorption path length of 55.1 m. The WMS signals from the first and second harmonic output of a lock-in amplifier (WMS-1 f and 2 f, respectively) agree with the Beer-Lambert law, especially at low concentrations. After boxcar averaging, the minimum detection limit achieved is 4.3 ppm for a measurement time of 0.125 s. The corresponding normalized detection limit is 84 ppm m Hz -1/2 . If the integrated time is increased to 88 s, the minimum detectable limit of CO can reach to 0.29 ppm based on an Allan variation analysis. The pressure-dependent relationship is validated after accounting for the pressure factor in data processing. Finally, a linear correlation between the WMS-2 f amplitudes and gas concentrations is obtained at concentration ratios less than 15.5%, and the accuracy is better than 92% at total pressure less than 62.7 Torr.