Stably suppressing laser relative intensity noise on a 3 × 3 coupler interferometric system.

A 3 × 3 coupler multiphase demodulation scheme is proposed to eliminate the impact of working point drifting and the laser relative intensity noise (RIN) on a 3 × 3 coupler interferometric system. An ellipse-fitting algorithm (EFA) is applied to fit the two interference signals of the 3 × 3 coupler in order, then the ATAN algorithm is applied to obtain three noise-containing signals with specific trigonometric relationships. By averaging the three signals, the demodulated phase noise induced from RIN can be effectively eliminated. The experimental results show that compared with the asymmetric demodulation scheme without intensity noise control, the noise floor of the proposed scheme decreases from 4.5 to 1 µrad/√Hz at 1 kHz and 2.7 to 0.8 µrad/√Hz at 3 kHz. At high frequencies, the average noise floor level is reduced from 10 to 0.9 µrad/√Hz, a reduction of about 21 dB. Furthermore, the variation range of the average noise floor is reduced from 5.4 to 0.17 µrad /√Hz within 100 s.

Surface-Pore-Modified N-Doped Amorphous Carbon Nanospheres Tailored with Toluene as Anode Materials for Lithium-Ion Batteries.

The surface modification of amorphous carbon nanospheres (ACNs) through templates has attracted great attention due to its great success in improving the electrochemical properties of lithium storage materials. Herein, a safe methodology with toluene as a soft template is employed to tailor the nanostructure, resulting in ACNs with tunable surface pores. Extensive characterizations through transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms elucidate the impact of surface pore modifications on the external structure, morphology, and surface area. Electrochemical assessments reveal the enhanced performance of the surface-pore-modified carbon nanospheres, particularly ACNs-100 synthesized with the addition of 100 µL toluene, in terms of the initial discharge capacity, rate performance, and cycling stability. The interesting phenomenon of persistent capacity increase is ascribed to lithium ion movement within the graphite-like interlayer, resulting in ACNs-100 experiencing a capacity upswing from an initial 320 mAh g-1 to a zenith of 655 mAh g-1 over a thousand cycles at a rate of 2 C. The findings in this study highlight the pivotal role of tailored nanostructure engineering in optimizing energy storage materials.

Unveiling Carrier Relaxation Mechanism in Protonated/Deprotonated Carbon Dots and Their Solvent Effects via Ultrafast Spectroscopy.

The intricate nature of the surface structure of carbon dots (CDs) hinders a comprehensive understanding of their emission behavior. In this study, we employ two types of CDs created through acid-alkali treatments, one with surface protonation and the other with surface deprotonation, with the objective of investigating the impact of these surface modifications on carrier behavior using ultrafast spectroscopy techniques. TEM, XRD, FTIR and Raman spectra demonstrate the CDs' structure, featuring graphitic core and abundant surface functional groups. XPS confirms the successful surface modifications of CDs via protonation and deprotonation. Ultrafast transient absorption (TA) spectroscopy reveals that deprotonation modification may decelerate the relaxation process, thereby increasing the visible PL quantum yields (PLQY). Conversely, protonation may accelerate the relaxation process due to the induced low-energy absorption band, resulting in self-absorption and reduced PLQY. Furthermore, TA analysis of CDs in mixed solvents with different proportions of ethanol shows the beneficial effect of ethanol in decelerating the relaxation process, leading to an increased PLQY of 33.7 % for deprotonated CDs and 22.1 % for protonated CDs. This study illuminates the intricate relationship between surface deprotonation/protonation modifications and carrier behavior in CDs, offering a potential avenue for the design of high-brightness CDs for diverse applications.

The relationship between presenteeism among nurses and patients' experience in tertiary hospitals in China.

This study aims to observe the current situation of nurses' presenteeism and the relationship between presenteeism among nurses and patient perceptions and examine its implications for nursing management. The study design was quantitative, correlational and cross-sectional. The researchers used convenience samples of nurses and patients from five hospitals who agreed to participate in an online survey distributed using Sojump Survey Software. A total of 500 in-service nurses from five tertiary hospitals in Henan Province in China were recruited as the nurse participants. Among them, 433 met the inclusion criteria and completed the general information questionnaire and the presenteeism scale. Patients who were hospitalised for three days or more and were cared for by one or more nurse participants were included in the study. In total, 435 patient participants answered the Inpatient Experience Questionnaire. The responses collected from both groups were analysed using descriptive and inferential statistics.Nurses' presenteeism was a key factor that affected patient experience. Presenteeism among nurses is a common phenomenon. Although patients' experience was overall positive, there is still room for improvement. Reducing presenteeism among nurses is crucial for improving patient experience, creating harmonious nurse-patient relationships and sharing a common mission.

Phase noise suppression technique based on an improved reference interferometer scheme.

The reference interferometer scheme is an effective noise reduction method, but the optical path length difference (OPD) of the two interferometers must be strictly equal, which limits its application in practical environments. In this paper, an improved reference interferometer demodulation technique without strictly equal OPDs is proposed to suppress phase noise. By introducing a reference interferometer, the phase noise can be removed from the demodulation results. The combination of the differential self-multiplication algorithm and the fitted phase modulation depth calculation formula can evaluate the phase modulation depth of both interferometers in real time and simultaneously eliminate the nonlinear distortion caused by phase modulation depth drift and the effect of different OPDs on the reference interferometer scheme. The experimental results show that the technique can obtain highly stable and accurate demodulation results even if the OPDs of the two reference interferometers are different. The phase modulation depth calculation error is less than 0.57%, the maximum phase noise reduction is 15 dB, the average reduction is 9 dB, the minimum total harmonic distortion is 0.17%, and the SINAD reaches 35.90 dB.

Improved ellipse-fitting phase demodulation technique to suppress the effect of light source intensity noise in interferometric system.

An improved ellipse-fitting algorithm phase demodulation (EFAPD) technique is proposed to reduce the influence of light source intensity noise on a system. In the original EFAPD, the sum of the intensities of coherent light (ICLS) is an important part of the interference signal noise, which makes the demodulation results suffer. The improved EFAPD corrects the ICLS and fringe contrast quantity of the interference signal by an ellipse-fitting algorithm, and then calculates the ICLS based on the structure of pull-cone 3 × 3 coupler, so as to remove it in the algorithm. Experimental results show that the noise of the improved EFAPD system is significantly reduced compared with that of the original EFAPD, with a maximum reduction of 35.57 dB. The improved EFAPD makes up for the deficiency of the original EFAPD in suppressing light source intensity noise, and promotes the application and popularization of EFAPD.

Ameliorated PGC demodulation technique based on the ODR algorithm with insensitivity to phase modulation depth.

For the optical fiber sensing system using phase generated carrier (PGC) technology, it is very important to eliminate the nonlinear effect of phase modulation depth (C) fluctuation on the demodulation results in the actual environment. In this paper, an ameliorated phase generated carrier demodulation technique is presented to calculate the C value and suppress its nonlinear influence on the demodulation results. The value of C is calculated out by the fundamental and third harmonic components with the equation fitted by the orthogonal distance regression algorithm. Then the Bessel recursive formula is used to convert the coefficients of each order of Bessel function contained in demodulation result into C values. Finally, the coefficients in demodulation result are removed by the calculated C values. In the experiment, when the C ranges from 1.0 rad to 3.5 rad, the minimum total harmonic distortion and maximum phase amplitude fluctuation of the ameliorated algorithm are 0.09% and 3.58%, which are far superior to the demodulation results of the traditional arctangent algorithm. The experimental results demonstrate that the proposed method can effectively eliminate the error caused by the fluctuation of the C value, which provides a reference for signal processing in practical applications of fiber-optic interferometric sensors.

Impact of Surface Trap States on Electron and Energy Transfer in CdSe Quantum Dots Studied by Femtosecond Transient Absorption Spectroscopy.

The presence of surface trap states (STSs) is one of the key factors to affect the electronic and optical properties of quantum dots (QDs), however, the exact mechanism of how STSs influence QDs remains unclear. Herein, we demonstrated the impact of STSs on electron transfer in CdSe QDs and triplet-triplet energy transfer (TTET) from CdSe to surface acceptor using femtosecond transient absorption spectroscopy. Three types of colloidal CdSe QDs, each containing various degrees of STSs as evidenced by photoluminescence and X-ray photoelectron spectroscopy, were employed. Time-resolved emission and transient absorption spectra revealed that STSs can suppress band-edge emission effectively, resulting in a remarkable decrease in the lifetime of photoelectrons in QDs from 17.1 ns to 4.9 ns. Moreover, the investigation of TTET process revealed that STSs can suppress the generation of triplet exciton and effectively inhibit band-edge emission, leading to a significant decrease in TTET from CdSe QDs to the surface acceptor. This work presented evidence for STSs influence in shaping the optoelectronic properties of QDs, making it a valuable point of reference for understanding and manipulating STSs in diverse QDs-based optoelectronic applications involving electron and energy transfer.

Highly sensitive temperature and strain sensor based on an antiresonant hollow core fiber probe with the Vernier effect.

A highly sensitive temperature and strain sensor based on an antiresonant hollow core fiber (ARHCF) probe with the Vernier effect is proposed and experimentally demonstrated. The ARHCF probe is used as a reference interferometer by sandwiching an ARHCF, which is insensitive to temperature, strain, and refractive index, between a single-mode fiber (SMF) and a polarization-maintaining fiber (PMF). The polarization mode interferometer (PMI), fabricated by splicing a section of PMF with a fiber polarizer at a 45-degree angle, works as a sensing interferometer. The Vernier effect is introduced by connecting the reference interferometer and the PMI in parallel. The experimental results show that by introducing the Vernier effect, the temperature sensitivity is improved from -1.68 to -15.7nm/∘C and the strain sensitivity is improved from 5.09 to 47.65 pm/µÎµ. The magnification is consistent with the theoretical results. The reference segment of the proposed sensor is not affected by ambient factors, which provides a new strategy and idea for the development of multiparameter sensors based on the Vernier effect.

Nurses' Job Insecurity and Emotional Exhaustion: The Mediating Effect of Presenteeism and the Moderating Effect of Supervisor Support.

Presenteeism refers to attending work when one is ill, which not only leads to a decline in the physical and mental health of employees but also negatively impacts organizational productivity and increases an organization's extra costs. Therefore, to explore the antecedents and outcomes of nurses' presenteeism behavior and the acting mechanism among the variables, a sample of 330 nurses from China were investigated with the Sickness Presenteeism Questionnaire, Job Insecurity Scale, Perceived Supervisor Support Scale, and Emotional Exhaustion Scale. The results indicated that (1) job insecurity had a significantly predictive effect on nurses' presenteeism behavior; (2) nurses' presenteeism partially mediated the relationship between job insecurity and emotional exhaustion; and (3) supervisor support moderated the relationship between nurses' presenteeism behavior and emotional exhaustion; i.e., the higher the level of supervisor support, the weaker the positive relationship between nurses' presenteeism behavior and emotional exhaustion. The findings provide theoretical guidance and an empirical basis for prevention and intervention strategies concerning nurses' presenteeism behavior.

The Effect of Presenteeism on Productivity Loss in Nurses: The Mediation of Health and the Moderation of General Self-Efficacy.

Background: Seventy-four percent of Chinese employees have experienced working with illness, but limited number of researchers have paid attention on this phenomenon. Most of the previous research on presenteeism has almost exclusively focused on North America and Europe and have gone to the financial emphasis. The current researches have two shortages, which are laying in the consensus on the definition and measurement of presenteeism, as well as the mechanism of presenteeism and its outcomes have set barriers for scholars to generate deeper understanding of the behavior. The aim of the present study was to explore the current situation of presenteeism among Chinese nurses and the mediating effect of health and the moderating effect of general self-efficacy between presenteeism and productivity loss. Methods: Data were collected from a sample of 340 female nurses from a 3A-graded general hospital in Henan Province, China by using the Sickness Presenteeism Questionnaire (SPQ), the Stanford Presenteeism Scale (SPS-6), the 12-item General Health Questionnaire (GHQ-12), and the General Self-Efficacy Scale (GSES). Results: The results indicated that the mean of SPQ was 3.2 ± 0.7 in this sample, and there were significant differences in age and marital status in SPQ scores. Presenteeism was significantly associated with health and productivity loss, and health was significantly associated with productivity loss, and general self-efficacy was negatively associated with productivity loss. A bootstrap test showed that health fully mediated the relationship between presenteeism and productivity loss in nurses. Hierarchical regression analysis confirmed the moderating role of general self-efficacy between presenteeism and productivity loss. Conclusions: Presenteeism can significantly predict productivity loss in nurses, and hospital management can improve the physical and mental health of nurses and enhance their self-efficacy level to reduce the negative impact of presenteeism on productivity loss.

Hsa-let-7g miRNA targets caspase-3 and inhibits the apoptosis induced by ox-LDL in endothelial cells.

It has been well confirmed ox-LDL plays key roles in the development of atherosclerosis via binding to LOX-1 and inducing apoptosis in vascular endothelial cells. Recent studies have shown ox-LDL can suppress microRNA has-let-7g, which in turn inhibits the ox-LDL induced apoptosis. However, details need to be uncovered. To determine the anti-atherosclerosis effect of microRNA has-let-7g, and to evaluate the possibility of CASP3 as an anti-atherosclerotic drug target by has-let-7g, the present study determined the role of hsa-let-7g miRNA in ox-LDL induced apoptosis in the vascular endothelial cells. We found that miRNA has-let-7g was suppressed during the ox-LDL-induced apoptosis in EAhy926 endothelial cells. In addition, overexpression of has-let-7g negatively regulated apoptosis in the endothelial cells by targeting caspase-3 expression. Therefore, miRNA let-7g may play important role in endothelial apoptosis and atherosclerosis.