Search

The combination of strong earthquakes and wave action may pose risks to the safety of sea-crossing bridges during their service life, resulting in damage to the bridges. To investigate the damage evolution laws of reinforced concrete rigid-frame bridges under combined earthquake and wave action, a novelty simplified numerical method was developed, which was then verified using the results of underwater shaking table tests on a bridge pier. Then, a reinforced concrete rigid-frame bridge modelled by nonlinear fibre damage elements was established and a damage evaluation method was proposed to evaluate the seismic damage evolution processes of the bridge under different wave environments, including various earthquake-wave phase differences, wave directions and wave levels. The obtained results show that the simultaneous effects of earthquakes and waves may increase or decrease bridge damage, which is related to earthquake-wave phase differences. The simultaneous effects of earthquakes and longitudinal waves significantly exacerbate bridge damage compared to those of earthquakes and transverse waves. For the bridge in the largely intact status, the bridge damage index increases with greater wave level. For the bridge in the slight damage status, wave action slightly increases bridge damage at the low-intensity phase in the latter part of the seismic record. • A novelty simplified numerical model of bridges considering the combined action of earthquakes and waves is developed. • A damage evaluation method for the reinforced concrete rigid-frame bridge is proposed. • The damage evolution processes of the bridge under combined strong earthquake and wave action are investigated. • The effects of the earthquake-wave phase difference, wave direction and wave level on the bridge are explored. [ABSTRACT FROM AUTHOR]

Represented here is an electron-optic Q switch Ho:ScSi 2 O 5 laser. A RTP crystal was employed as the Q-switch element. It is the first time to demonstrate an electron-optic Q switch Ho:ScSi 2 O 5 laser, whose maximum single-pulse energy reaches around 102 mJ, corresponding to a maximum peak power of 2.91 MW. The laser performance is investigated as a function of the different repetition frequencies and incident pump power. We focus on the low frequencies (1, 2, 5, 8, 10, and 20 Hz) in this contribution, aiming to obtain a higher single-pulse energy. The beam quality M 2 factor of the electron-optic Q switch Ho:ScSi 2 O 5 laser is measured by knife-edge method, which is calculated to be 1.24. [ABSTRACT FROM AUTHOR]

A Ho:SSO crystal was employed as an efficient saturable absorber Q switch for the pulsed Ho:YAG laser for the first time. The characteristics of the passive Q-switch Ho:YAG laser were studied with different incident pump power and different laser energy density around the Ho:SSO. The single pulsed energy varied from 8.3 μJ to 76.6 μJ with the increasing of the incident power from 2.2 W to 8.2 W. The maximum repetition rate was 42.1 kHz, and the minimum pulsed duration was 48 ns. The maximum single-pulse peak power was 1.53 kW. The output center wavelength shifted from 2090.1 nm (the continuous-wave mode) to 2091.3 nm (the passive Q-switch mode). [ABSTRACT FROM AUTHOR]

A double Q-switch (DQS) Ho:Sc 2 SiO 5 laser modulated by a acousto-optic modulators (AOM) combined with a Cr 2+ :ZnSe saturable absorber (SA) was reported for the first time. The actively Q-switch (AQS) and passively Q-switch (PQS) were also studied. For the DQS mode, a maximum average output power of 2.49 W under the incident pump power of 12.5 W was obtained, corresponding to a slope efficiency of 24%. The characteristics of the DQS Ho:SSO laser versus different repetition frequencies (RF) of the AOM were researched. The maximum single-pulse energy of the DQS Ho:SSO laser was calculated to 1.98 mJ. The maximum peak power of the DQS Ho:SSO laser was 49.5 kW. The output beam quality factor M 2 of DQS Ho:SSO laser was measured to be 1.15 with the highest peak power by knife-edge method at different positions. [ABSTRACT FROM AUTHOR]

A widely tunable Holmium-doped ScSiO(SSO) 2 μm laser is reported in this manuscript, which has a wavelength tunable range of 110 nm (from 2050 to 2160 nm). A maximum output power of 3.02 W at 2111 nm is obtained when the laser operates on the continuous-wave free-running mode. A birefringent filter is used to realize the output wavelength tuning, which is put into the laser resonant cavity. The maximum output power of the tunable Ho:SSO laser is 2.07 W. It is the first time to report a widely tunable Ho:SSO laser. The wavelength tunable range is wider than the ones of other Ho-doped lasers and the output power is higher too, which could extend application fields of the Ho-doped lasers. [ABSTRACT FROM AUTHOR]

This work investigates the feasibility of TDLAS technique in the NO concentration measurement for the marine diesel engine. A system in laboratory is devised for the NO steady state measurement. An ICL laser whose center wavelength is 5263 nm is chosen for the detection. With the direct detection method, a resolution about 2 ppm is realized, and the relative error is less than 5%. In contrast to the direct detection method, the harmonic detection method realizes a higher resolution, and the error is better less 3%. Considering with the temperature fluctuation of the diesel emission, the absorption line strength is calculated from 300 K to 500 K. At the same time, the intensity of the 2f signal is measured, which is proportional to the change of the line strength. So a modification can be imported easily to avoid the error produced by the temperature fluctuation. The TDLAS proposed in this work can realize a high precision, high resolution, and transient measurement for the marine diesel emission. [ABSTRACT FROM AUTHOR]

A compact intra-cavity pumped low threshold continuous-wave Ho:Sc 2 SiO 5 laser is reported. The characteristics of output wavelength tuning are investigated by use a intra-cavity briefringent (BF) filter. A wavelength tunable range of 140 nm from 2020 to 2160 nm is achieved. For the free-running mode, the laser slope efficiency is 24.8%, when the output central wavelength is 2110 nm. The laser threshold is about 820 mW of incident pump power. With the BF filter, a maximum output power of 870 mW is obtained at the incident pump power of 5 W, corresponding to a slope efficiency of 20.3%. The characteristics of output wavelength verse the crystal temperature are also investigated. [ABSTRACT FROM AUTHOR]

Diabetes is a chronic disease that poses a serious threat to health, and its early risk prediction has been a hot research topic in the field of medical artificial intelligence. Routine medical checkups are the most common way to monitor people's health status, and the data from medical checkups contain rich diagnostic information, which is valuable for diabetes risk prediction. Currently, most of the available studies on diabetes risk prediction are based on publicly available datasets, and the models and algorithms do not work well on real clinical datasets. Real routine checkup data are characterized by complex information, diverse features, high redundancy and poor balance, which pose great challenges for diabetes risk prediction. To address this problem, this paper proposes a multi-strategy data augmentation-based diabetes risk prediction method, after completing data pre-processing and feature selection, a counterfactual-based data balancing strategy is used to augment a minority class of instances, and a density clustering-based supplemental counterfactual data augmentation strategy is proposed to address the problem of insufficient representation of generated instances in the counterfactual method. Moreover, the uncertainty-weighted method is used in the model training phase. Based on the real checkup dataset, five machine learning methods including Logistic Regression (LR), SVM, Decision Tree, Random Forest and Gradient Boosting are used to model and use 5-fold cross-validation to carry out diabetes risk assessment and prediction. The experimental results showed that the sensitivity and precision of the models were significantly improved compared with the existing methods, and the sensitivity of the LR model for diabetes risk prediction on the real routine checkup dataset reached more than 90 % , which meet the requirements of clinical application. [ABSTRACT FROM AUTHOR]

This work investigates a tunable laser absorption spectroscopy technique for the H 2 O concentration by a Tm:YAP solid-state laser. The output wavelength of Tm:YAP laser is tuned by a birefringence filter and an F-P etalon in the laser cavity. The tuning range is from 1910 nm to 1914 nm, the tuning frequency is 1 Hz. With the tunable Tm:YAP laser, we realize a concentration resolution of 10 ppb. Different concentrations of H 2 O vapor are use to test the precision of the system. A maximum relative error of 0.8% is realized. At the same time, we calculate the maximum absolute error to be 0.8 ppm. Up to the authors’ knowledge, it is the first time to report a tunable laser absorption spectroscopy for the gas concentration measurement by a Tm-doped laser. [ABSTRACT FROM AUTHOR]

Abstract Objective To explore the clinical characteristics and etiology of bacterial meningitis (BM) in Chinese children. Method BM cases in children 28 days to 18 years old were collected from January 2014–December 2016 and screened according to World Health Organization standards. Clinical features, pathogens, and resistance patterns were analyzed. Results Overall, 837 cases were classified into five age groups: 28 days–2 months (17.0%), 3–11 months (27.8%), 12–35 months (24.0%), 3–6 years (13.9%), and >6 years (17.3%). Major pathogens were Streptococcus pneumoniae (S. pneumoniae, n = 136, 46.9%), group B Streptococcus (GBS, n = 29, 10.0%), and Escherichia coli (E. coli, n = 23, 7.9%). In infants <3 months old, GBS (46.5%) and E. coli (23.3%) were most common; in children >3 months old, S. pneumoniae (54.7%), which had a penicillin non-susceptibility rate of 55.4% (36/65), was most frequent. The resistance rates of S. pneumoniae and E. coli to cefotaxime and ceftriaxone were 14.0%/40.0% and 11.3%/68.4%, respectively. All GBS isolates were sensitive to penicillin. Conclusions The occurrence of BM peaked in the first year of life, while S. pneumoniae was the predominant pathogen in children >3 months of old. The antibiotic resistance of S. pneumoniae was a concern. [ABSTRACT FROM AUTHOR]