Abstract This study employs four waves of survey data on 1,135 families from the Illinois Families Study, a longitudinal panel study of Temporary Assistance for Needy Families in Illinois. This study ...explores the following issues within this low-income population: (1) whether material hardships are associated with child protective services (CPS) investigations, (2) whether the effect of material hardship on CPS differs by the type of child maltreatment investigated, and (3) whether psychological distress mediates the association between material hardship and CPS involvement. Results from pooled and fixed effects logistic regressions suggest that caregivers who experience material hardship are more likely to become involved in CPS. In general, investigated neglect reports are responsive to particular types of hardship such as housing and food, while investigated physical abuse reports are responsive to levels of hardship regardless of specific types. The association between material hardship and CPS involvement is not fully explained by depressive symptoms or parenting stress. The study results suggest that in order to prevent child maltreatment, it may be necessary to address a family's unmet material needs through economic support interventions.
This paper presents a novel coordinated energy management approach for hybrid AC/DC distribution system with microgrid clusters considering multiple market players, which is modeled as a bi-level ...optimization problem by using noncooperative game theory and robust optimization. The hybrid AC/DC distribution network and each microgrid are regarded as different entities, which are in the upper/lower level of the model, respectively. Considering the uncertainty of renewable energy, two-stage robust optimization is added in the bi-level optimization problem to suppress the influence of uncertainty on power interaction and achieve the minimum operation costs of each entity under uncertainty. Furthermore, In the upper level model, hybrid AC/DC distribution network can control power flow in real time, promote power interaction between entities, and reduce operation cost under uncertainty by using effective control of converter station and diesel generator. And each microgrid has dealt with the impact of uncertainty on the power interaction by reasonably managing the charge/discharge of energy storage, which realizes its own minimum operation cost. The proposed model can be transformed into mathematical programming with complementarity constraints (MPCC) by using Karush-KuhnTucker conditions. Finally, numerical cases on an improved IEEE 33-bus hybrid AC/DC distribution system show the effectiveness of the proposed method.
TiO2 is the most promising semiconductor for photocatalytic splitting of water for hydrogen and degradation of pollutants. The highly photocatalytic active form is its mixed phase of two polymorphs ...anatase and rutile rather than their pristine compositions. Such a synergetic effect is understood by the staggered band alignment favorable to spatial charge separation. However, electron migration in either direction between the two phases has been reported, the reason of which is still unknown. We determined the band alignment by a novel method, i.e., transient infrared absorption-excitation energy scanning spectra, showing their conduction bands being aligned, thus the electron migration direction is controlled by dynamical factors, such as varying the particle size of anatase, putting electron or hole scavengers on either the surface of anatase or rutile phases, or both. A quantitative criterion capable of predicting the migration direction under various conditions including particle size and surface chemical reactions is proposed, the predictions have been verified experimentally in several typical cases. This would give rise to a great potential in designing more effective titania photocatalysts.
Based on the decentralized sliding mode control, a load frequency controller is designed in this paper for multi-area interconnected power systems with matching and unmatched uncertainties. The ...proportional and integral switching surface is constructed for each area to improve system dynamic performance in reaching intervals. The robust controller is proposed by the reaching law method to assure that frequency fluctuation converges to zero after a load and operation point variation. A three-area interconnected power system is studied to illustrate the effectiveness of the proposed decentralized sliding mode control scheme.
Wind power may become the key development area of the renewable energy industry planning. Due to the fluctuated wind output power, the system parameter uncertainties and load disturbances, these may ...lead to the unstable operation of renewable energy power system for the larger voltage deviation. Therefore, the novel control strategy is proposed for the load side converter (LSC) of double-fed induction generator (DFIG) to improve the stability of power system, which is designed by taking advantage of adaptive sliding mode (SM) method and sliding mode observer (SMO). Furthermore, the static synchronous compensator (STATCOM) is also controlled through the designed adaptive SM reactive power controller, which can supply the reactive power compensation for the interconnected wind-diesel power system. Moreover, the LSC state variables need to be estimated by the SMO, which is constructed according to the established mathematical state model. Based on the estimated state variables, the designed reactive power controller is established for LSC by adaptive SM algorithm and fuzzy algorithm. The reactive power controller includes two parts. One is the designed SM controller by taking advantage of the estimated state variables and state control model. The other is micro-regulated part and the control signal is calculated by using fuzzy algorithm according to the system voltage deviation online. Experiment studies are performed by using RTDS to verify the effectiveness of the proposed strategy and assure the stability of wind-diesel power system under different operation conditions.
Extracellular vesicles (EVs) contain specific proteins, lipids, and nucleic acids that can be passed to other cells as signal molecules to alter their function. However, there are many problems and ...challenges in the conversion and clinical application of EVs. Storage and protection of EVs is one of the issues that need further research. To adapt to potential clinical applications, this type of problem must be solved. This review summarizes the storage practices of EVs in recent years, and explains the impact of temperature on the quality and stability of EVs during storage based on current research, and explains the potential mechanisms involved in this effect as much as possible.
Extracellular vesicles (EVs) contain specific proteins, lipids, and nucleic acids that can be passed to other cells as signal molecules to alter their function. However, there are many problems and challenges in the conversion and clinical application of EVs. Storage and protection of EVs is one of the issues that need further research. To adapt to potential clinical applications, this type of problem must be solved. Here, we briefly review EVs' biogenesis, contents, subtypes and effect of storage temperature on its quality and stability, as well as application of cryoprotectants in EVs cryopreservation, and specifically focus on the mechanism by which storage temperature affects the quality and stability of EVs.
Nonfullerene polymer solar cells (PSCs) are fabricated by using one wide bandgap donor PBDB‐T and one ultranarrow bandgap acceptor IEICO‐4F as the active layers. One medium bandgap donor PTB7‐Th is ...selected as the third component due to the similar highest occupied molecular orbital level compared to that of PBDB‐T and their complementary absorption spectra. The champion power conversion efficiency (PCE) of PSCs is increased from 10.25% to 11.62% via incorporating 20 wt% PTB7‐Th in donors, with enhanced short‐circuit current (JSC) of 24.14 mA cm−2 and fill factor (FF) of 65.03%. The 11.62% PCE should be the highest value for ternary nonfullerene PSCs. The main contribution of PTB7‐Th can be summarized as the improved photon harvesting and enhanced exciton utilization of PBDB‐T due to the efficient energy transfer from PBDB‐T to PTB7‐Th. Meanwhile, PTB7‐Th can also act as a regulator to adjust PBDB‐T molecular arrangement for optimizing charge transport, resulting in the enhanced FF of ternary PSCs. This experimental result may provide new insight for developing high‐performance ternary nonfullerene PSCs by selecting two well‐compatible donors with different bandgap and one ultranarrow bandgap acceptor.
Highly efficient ternary nonfullerene polymer solar cells (PSCs) are fabricated by employing two well‐compatible donors with complementary absorption spectra and one ultranarrow bandgap acceptor. The power conversion efficiency and short‐circuit current density of ternary PSCs are simultaneously increased to 11.62% and 24.14 mA cm−2 by incorporating 20 wt% PTB7‐Th due to the enhanced photon harvesting and optimized film morphology.
Shadow removal can significantly improve the image visual quality and has many applications in computer vision. Deep learning methods based on CNNs have become the most effective approach for shadow ...removal by training on either paired data, where both the shadow and underlying shadow-free versions of an image are known, or unpaired data, where shadow and shadow-free training images are totally different with no correspondence. In practice, CNN training on unpaired data is more preferred given the easiness of training data collection. In this paper, we present a new Lightness-Guided Shadow Removal Network (LG-ShadowNet) for shadow removal by training on unpaired data. In this method, we first train a CNN module to compensate for the lightness and then train a second CNN module with the guidance of lightness information from the first CNN module for final shadow removal. We also introduce a loss function to further utilise the colour prior of existing data. Extensive experiments on widely used ISTD, adjusted ISTD and USR datasets demonstrate that the proposed method outperforms the state-of-the-art methods with training on unpaired data.
Non-fullerene polymer solar cells (PSCs) attract more attention due to the constantly refreshed power conversion efficiency (PCE) based on the versatile non-fullerene acceptors. In this work, PCEs of ...10.51% and 11.02% were obtained for two kinds of non-fullerene PSC with IDT6CN-M or ITCPTC as the acceptor and PBDB-T as the donor. ITCPTC has a relatively narrow bandgap and a high absorption coefficient compared with IDT6CN-M, which explains well the relatively large short-circuit current density of 17.44 mA cm −2 for the ITCPTC based binary PSCs. Meanwhile, the IDT6CN-M based binary PSCs exhibit a relatively high fill factor (FF) of 75.3% and an open-circuit voltage of 0.915 V. A PCE of 11.92% and a FF of 76.5% were achieved for the ternary PSCs with 60 wt% ITCPTC content in the acceptors, which should be attributed to the enhanced photon harvesting and their good compatibility for a synergistic improvement of exciton utilization and charge transport in the ternary active layers. The FF of 76.5% is among the top values of ternary non-fullerene PSCs.
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