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Natural sunlight activated persistent luminescence (PeL) is ideal candidate for optical information display in outdoors without the requirement of electric supply. Except the brightness and duration, the stability especially water resistance of the PeL materials is of significant importance for practical application, which remains a great obstacle up to date. Herein, we report a new sunlight activated PeL glass ceramic containing hexagonal Sr13Al22Si10O66:Eu2+ crystals, which exhibits strong blue PeL and can last more than 200 h. The PeL can be charged by the full wavelengths located in AM 1.5G due to the broad distribution of traps in the crystal structure. The PeL is clearly observed by the naked eye even after 24 h upon sunlight irradiation irrespective of the weather, and the photoluminescence intensity only decreased ∼3.3% after storing in water for 365 d. We demonstrate its potential application for thermal and stress responsive display as well as long-term continuous security indication upon sunlight irradiation, which not only save vast energy and reduce environment pollution, but also are appropriate for outdoor usage.

The effective management of stochastic characteristics of renewable power generations is vital for ensuring the stable and secure operation of power systems. This paper addresses the formidable task of optimizing the chance-constrained voltage-stability-constrained optimal power flow (CC-VSC-OPF) problem, which is hindered by the implicit voltage stability index and intractable chance constraints. Leveraging a neural network (NN)-based surrogate model, the stability constraint is explicitly formulated and seamlessly integrated into the model. To perform uncertainty propagation without relying on presumptions or complicated transformations, an advanced data-driven method known as adaptive polynomial chaos expansion (APCE) is developed. To extend the scalability of the proposed algorithm, a partial least squares (PLS)-NN framework is designed, which enables the establishment of a parsimonious surrogate model and efficient computation of large-scale Hessian matrices. In addition, a dimensionally decomposed APCE (DD-APCE) is proposed to alleviate the "curse of dimensionality" by restricting the interaction order among random variables. Finally, the above techniques are merged into an iterative scheme to update the operation point. Simulation results reveal the cost-effective performances of the proposed method in several test systems.

To operate the power grid safely and reduce the cost of power production, power-load forecasting has become an urgent issue to be addressed. Although many power load forecasting models have been proposed, most still suffer from poor model training, limitations sensitive to outliers, and overfitting of load forecasts. The limitations of current load-forecasting methods may lead to the generation of additional operating costs for the power system, and even damage the distribution and network security of the related systems. To address this issue, a new load prediction model with mixed loss functions was proposed. The model is based on Pinball–Huber’s extreme-learning machine and whale optimization algorithm. In specific, the Pinball–Huber loss, which is insensitive to outliers and largely prevents overfitting, was proposed as the objective function for extreme-learning machine (ELM) training. Based on the Pinball–Huber ELM, the whale optimization algorithm was added to improve it. At last, the effect of the proposed hybrid loss function prediction model was verified using two real power-load datasets (Nanjing and Taixing). Experimental results confirmed that the proposed hybrid loss function load prediction model can achieve satisfactory improvements on both datasets.

A novel fluorescence chemical sensor-based probe 1-{[(E)-(2-aminophenyl)azanylidene]methyl}naphthalen-2-ol (AMN) was designed and synthesized, which performed a “naked eye” detection ability toward Cu2+ and Co2+ based on aggregation-induced emission (AIE) fluorescence strategy. It has sensitive detection ability for Cu2+ and Co2+. In addition, the color changed from yellow-green to orange under the sunlight, realizing the rapid identification of Cu2+/Co2+, which has the potential of on-site visual detection under the “naked eye”. Moreover, different “on” and “off” fluorescence expressions were exhibited under excessive glutathione (GSH) in AMN-Cu2+ and AMN-Co2+ systems, which could be employed to distinguish Cu2+ from Co2+. The detection limits for Cu2+ and Co2+ were measured to be 8.29 × 10−8 M and 9.13 × 10−8 M, respectively. The binding mode of AMN was calculated to be 2:1 by Jobs’ plot method analysis. Ultimately, the new fluorescence sensor was applied to detect Cu2+ and Co2+ in real samples (tap water, river water, and yellow croaker), and the results were satisfying. Therefore, this high-efficiency bifunctional chemical sensor platform based on “on–off” fluorescence detection will provide significant guidance for the advance development of single-molecule sensors for multi-ion detection.

Hot dry rocks, as clean and abundant sources of new energy, are crucial in the restructuring of energy. Predicting the temperature field of hot dry rocks is of great significance for trapping the target areas of hot dry rocks. How to use limited logging data to predict the temperature field within a work area is a difficulty faced in hot dry rock exploration. We propose a method to predict the hot dry rock temperature field (using seismic inversion results). The relationship between porosity and transverse wave velocity was established with petrophysical modeling. The difference in porosity calculated from the density and transverse wave velocity was incorporated in the seismic inversion results to find the thermal expansion and predict the temperature field. We applied the method to predict the temperature of hot dry rocks in the Gonghe Basin. The results showed that the temperature in the northeast work area was higher than in the southwest area at the same depth, and a depth of 150 °C of the hot dry rock reservoir was shallower. The thermal storage cover was analyzed from the geological stratigraphic data of the Gonghe Basin. The thermal storage cover in the northeastern part was thicker than in the southwestern part and had better thermal insulation, which is consistent with the prediction of the temperature field.

The North Pacific subtropical gyre (NPSTG) redistributes heat and moisture between low and high latitudes and plays a key role in modulating the global climate change and ecosystem. Recent evidence suggests intensification and poleward shift of the subtropical gyres over the last decades due to global warming, but insufficient observations have hampered insight into the integrated effects of ocean-atmosphere interactions at longer timescales. Here we present the first high-resolution (∼12 years) grain-size record from Core CF1 in the Okinawa Trough, western subtropical North Pacific, to reconstruct the evolution of the western boundary Kuroshio Current (KC) of NPSTG during the Late Holocene. Our results indicate the KC slow-down during 4.6–2.0 ka, followed by quick enhancement after 2.0 ka, with centennial-scale variabilities (500–700 years) superimposed on the long-term trend. Over millennial timescales, gradually increased pole-to-equator thermal gradient, due to orbital forcing mechanisms, resulted in long-term enhanced KC, whereas solar activity triggered phase changes in the tropical Pacific mean state and controlled KC anomalies on centennial timescales. We suggest that both forcing mechanisms resulted in ocean-atmosphere feedback provoking concurrent changes in mid-latitude westerly and subtropical easterly winds over the North Pacific, alternating their dominance as source regions causing the dynamic changes of KC at different timescales. Our findings offer insight into the role of external forcing mechanisms in the NPSTG changes before the Anthropocene, which have profound implications for the deeper understanding of changes in ocean gyres under global warming scenarios.

Europium doped borosilicate glasses were prepared in CO reducing atmosphere. The glasses were systematically investigated through XPS, photoluminescence (PL), fluorescence decay curves and X-ray excited luminescence (XEL). XPS results show that the glasses contain Eu2+ and Eu3+ at the same time. Under the excitation of 360 nm light, only a broad blue emission with peak around 440 nm due to the 5d→4f transition of Eu2+ is observed, while the emissions from Eu3+ do not appear in the PL spectra. The fluorescence decay curves were monitored at 440 nm, and the measured lifetimes are in the range of 0.17–0.42 μs. The PL results indicate that the PL emission from Eu2+ is significantly intense than the PL emissions from Eu3+. Upon X-ray excitation, two main emissions with peaks at 445 nm and 616 nm corresponding to Eu2+ and Eu3+ are obtained. The XEL results reveal that the XEL emissions from Eu3+ are comparably intense as the XEL emission from Eu2+. The results indicate that europium doped borosilicate glass could be a potential scintillating material in X-ray detection filed.

Eu3+ doped tellurite scintillating glasses were prepared by the conventional melt-quenching method. The physical and luminescent properties of glasses were investigated by DTA, density, transmittance spectra, photoluminescence spectra, and X-ray excited luminescence (XEL) spectra. The densities of the glasses are in the range from 5.89 g/cm3 to 6.05 g/cm3. The glasses exhibit intense red emissions upon 393 nm light and X-ray excitations. The maximum integral XEL intensity of the glasses is about 6% of that of commercial Bi4Ge3O12 (BGO) scintillating crystal. The results reveal that Eu3+ doped tellurite glass could be a scintillator candidate used in X-ray detection field.

Changes in marine export productivity may have played a prominent role in the atmospheric CO2 rise and associated warming of the last deglaciation, via their impact on the air-sea partitioning of CO2. To study the evolution of marine export production in the western subtropical Pacific Ocean during the last deglaciation and the mechanisms governing these changes, 230Th-normalization has been applied on a sediment core retrieved from the Okinawa Trough. The reconstructed export productivity record shows two prominent peaks, centered around 14 and 17 ka. Given that phytoplankton growth at our study site is limited by the availability of nutrients today, elevated macro-nutrient supply must have been responsible for sustaining the two deglacial productivity peaks. Specifically, higher nutrient supply originating from the subpolar gyre via subsurface water advection, with enhanced vertical mixing in the subpolar gyre during early HS1 and enhanced wind-driven upwelling during the B/A, would have fueled phytoplankton productivity and export. In contrast, reduced nutrient supply to the euphotic zone caused by gyre circulation changes would have lead to decreased export production during the Holocene. These observations lend support to a predominant control of nutrient availability on the evolution of the marine carbon cycle in the subtropical west Pacific Ocean across the last deglaciation.

In the grounding system of the neutral point through the arc suppression coil, due to the compensation effect of the arc suppression coil (ASC) on the ground point fault current, the zero sequence current (ZSC) characteristic of the fault line is not obvious, which seriously affects the accuracy of single-phase ground fault line selection. Therefore, based on the analysis of the feasibility of adjusting the turn-adjusting arc suppression coil in the case of a single-phase ground fault, this paper proposes a new small-distance method to select the line technology for the turn-adjusting arc suppression coil. The results show that the method is highly reliable and practical, and can effectively improve the accuracy of line selection.

The application of the Internet of Things technology to agricultural electrification production, especially agricultural greenhouse cultivation, can greatly improve the quality of agricultural products. This article summarizes the application technology of the Internet of Things technology in five aspects of agricultural greenhouse insulation, electric rolling shutters, electric drainage and irrigation, electric supplementary light and electric ventilation. Deep integration with agricultural production to improve agricultural planting benefits.

Eu3+ doped transparent germanate glass ceramics containing LaF3 nanocrystals have been prepared by the conventional melt quenching technique with subsequent heat treatment. XRD, TEM and HRTEM were used to verify the formation of LaF3 nanocrystals. Emission spectra, fluorescence decay and X-ray excited luminescence (XEL) were employed to elucidate the optical properties of Eu3+ doped germanate glasses and glass ceramics. The maximum integrated XEL intensity of the glass ceramic is about 20% of that of the commercial Bi4Ge3O12 (BGO) scintillating crystal. The results indicate that Eu3+ doped germanate glass ceramic could be a promising scintillating material used in X-ray detection field.

The paper concerns on the reliability analysis method for microgrid with the intermittent distributed generations (DGs) and their power supply failure. Some types of DGs, such as photovoltaic and wind turbine, have the characteristic of intermittent and uncontrollable, which leads to unstable power output. It is worth to analyze and quantify the microgrid influence of DGs on the power supply reliability. In the paper, taking wind turbine as example, a multi-states power output model for intermittent DGs was provided with Markov chain. And then, a microgrid reliability analysis method, considering the influences of DGs intermittent and power supply failure, was proposed. The probability distribution of loads and power supplies are used, and a quantitative reliability indicator was given in the method, which could well reflect the microgrid reliability on various random factors. At last, an actual microgrid in Nanjing City was used to verify the feasibility and effectiveness of the proposed method.

A piston core Z14-6 was used in this study. The core, 896 cm long, was collected from eastern slope of the Okinawa Trough (27°07′N, 127°27′E, water depth 739m). The δ18O and δ13C values of the sediment bearing planktonic foraminiferaG. sacculifer andN. dutertrei were determined; and the abundance of volcanic glass was analyzed. The volcanic glass content high occurred in early stage of polar ice-sheet growth period, or the beginning of cold climate periods corresponding to Milankovitch cycles (Peak I, II and V are corresponding to the beginnings of oxygen isotopic stages 2, 4 and 6, and Peak III and IV are matching oxygen isotopic stage 5b–5d.). It might be possible that volcanic episodes and climate changes were responding to orbital forcing in the Okinawa Trough in late Quaternary. The δ18O difference betweenN. dutertrei andG. sacculifer shows no clear correlation to the volcanic glass content high, which suggests that the volcanic eruptions did not influence the structure of upper water column. However, the low δ13C difference betweenG. sacculifer andN. dutertrei is coeval with the volcanic glass high or sub-high content. This fact suggests that volcanic eruptions might influence the reduction in vertical nutritional gradient and carbon cycle process in upper water column. A possible mechanism is that huge quantity of ash and dust had weakened the light intensity, resulting in photosynthesis reduction, productivity decrease, and biological pumping.

Using the measured capacitance—voltage and current—voltage characteristics of the rectangular AlN/GaN heterostructure field-effect transistors (HFETs) with the side-Ohmic contacts, it was found that the polarization Coulomb field scattering in the AlN/GaN HFETs was greatly weakened after the side-Ohmic contact processing, however, it still could not be ignored. It was also found that, with side-Ohmic contacts, the polarization Coulomb field scattering was much stronger in AlN/GaN HFETs than in AlGaN/AlN/GaN and In0.17Al0.83N/AlN/GaN HFETs, which was attributed to the extremely thinner barrier layer and the stronger polarization of the AlN/GaN heterostructure.

Using the measured capacitance-voltage curves of Ni/Au Schottky contacts with different areas and the current-voltage characteristics for the AlGaAs/GaAs, AlGaN/AlN/GaN and In0.18 Al0.82N/AlN/GaN heterostructure field-effect transistors (HFETs) at low drain-source voltage, the two-dimensional electron gas (2DEG) electron mobility for the prepared HFETs was calculated and analyzed. It was found that there is an obvious difference for the variation trend of the mobility curves between the III–V nitride HFETs and the AlGaAs/GaAs HFETs. In the III–V nitride HFETs, the variation trend for the curves of the 2DEG electron mobility with the gate bias is closely related to the ratio of the gate length to the drain-to-source distance. While the ratio of the gate length to the drain-to-source distance has no effect on the variation trend for the curves of the 2DEG electron mobility with the gate bias in the AlGaAs/GaAs HFETs. The reason is attributed to the polarization Coulomb field scattering in the III–V nitride HFETs.