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Antimony selenide (Sb2Se3) is a promising light absorber material for solar cells because of its superior photovoltaic properties. However, the current performance of the Sb2Se3 solar cell is much lower than its theoretical value (∼32%) due to its low open-circuit voltage (VOC). In this paper, we have demonstrated inorganic vanadium oxides (VOx) as a hole transport layer (HTL) for Sb2Se3 solar cells to enhance efficiency through the VOC improvement. Here, a solution-processed VOx through the decomposition of the triisopropoxyvanadium (V) oxide is deposited on the Sb2Se3 absorber layer prepared by close-spaced sublimation (CSS). With VOx HTL, the built-in voltage (Vbi) is significantly increased, leading to improved VOC for the Sb2Se3 solar cell devices. As a result, the efficiency of the device increases from an average efficiency of 5.5% to 6.3% with the VOx.

Although perovskite solar cells (PSCs) have made revolutionary progress in terms of power conversion efficiency (PCE), to achieve long-term stability and low-cost device manufacturing for commercialization of the devices, selection of proper hole transport layer (HTL) and affordable back contact are still crucial to realize the upscale manufacturing. However, the carbon-based perovskite still faces great challenges to further improve the device performance due to the low quality of the carbon/perovskite interface. Inorganic NiOx is a superior HTL candidate due to its favorable energy band alignment, superior chemical stability, high hole mobility, and low-cost manufacturing. To address the poor interface quality of the carbon-based PSCs, we report electrospun NiOx fibers as an effective HTL, resulting in highly efficient device performance of PCEs up to 13.73% when deployed in our carbon-based PSCs. NiOx has been introduced as an interfacial layer between the perovskite and the carbon counter electrode to study its impact on interfacial modification and device performance.

Toxicodendron succedaneum (L.) Kuntze (T. succedaneum) is an economic tree species that produces urushiol and urushi wax, and it is of great value in industry and medicine. However, the stability of reference genes (RGs) has not been systematically reported in T. succedaneum to date. In this study, the expression of 10 candidate RGs was analyzed by RT-qPCR in different tissues (roots, stems, leaves), stress treatments (high/low temperature, drought), and hormone stimulation (jasmonic acid, JA). Then, the stability ranking of 10 candidate genes was evaluated by ∆Ct analysis and three software programs: geNorm, NormFinder, and BestKeeper. Finally, RefFinder was used to comprehensively analyze the expression stability of 10 candidate genes. The comprehensive analysis showed that TsRG05/06, TsRG01/06, and TsRG03/ACT were stable under high/low-temperature stress, drought stress, and JA treatment, respectively. TsRG03 and ACT had stable expression in different tissues. While the TsRG03 and ACT were recommended as the suitable RGs for T. succedaneum in all samples. Meanwhile, UBQ was the least suitable as a reference gene for T. succedaneum. In addition, the results of geNorm showed that the combination of two stable RGs could make the results of gene expression more accurate. These results provide alternative RGs for the study of gene function, correction, and normalization of target gene expression and directed molecular breeding in T. succedaneum.

A series of non-rare-earth red-emitting phosphors, Sr2−xBaxMgGe2O7:Mn4+, are prepared. Compared to the parent phosphor of Sr2MgGe2O7:Mn4+, the Ba2+-doped phosphors show unchanged crystal structure with slightly lattice distortion, which results in very similar excitation/emission spectra and thermal stability in emission, accompanying with increased luminescence and longer emission lifetime. The optimized phosphor exhibits emission quantum yield of 88%, decay lifetime of 3.59 ms and emission peak of 664 nm originating from the 2E → 4A2 spin- and parity-forbidden transition of Mn4+. At high temperature of 423 K, the emission intensity is still 94.3% of that at room temperature, showing excellent thermal stability of emission.

Sb2Se3 is a promising absorber material for thin-film solar cells owing to its earth-abundant and non-toxic constituents, superior optoelectronic properties, and unique one-dimensional crystal structure. To further increase the power conversion efficiency of the Sb2Se3, we fabricated an n-i-p structure by integrating a solution-processed NiOx hole-transport layer (HTL) into Sb2Se3 solar cells to enhance the carrier collection. In this study, we systematically screen the thickness of NiOx HTL and demonstrate an improved average power conversion efficiency from 6.12% to 7.15% with a 50 nm NiOx HTL. The mechanism associated with the improved device performance was characterized through the microstructure of the material, device physics, and interface electronic behaviors. It is also shown that the low-cost and scalable solution-processed NiOx HTL can improve device stability under an accelerated stress test. Thus, this work paves a way to further improve the performance of antimony chalcogenides-based solar cells via tailoring the inorganic HTL.

Compressive Imaging (CI) is a potential sensing technology for energy-efficient visual sensors, and its rate-distortion performance can be improved by adaptive Compressive Sensing (CS) of image. However, due to the unavailability of original image, it is a challenge for CI-based adaptive CS to extract an effective feature from measurements to evaluate the sparsity of image. In view of that, this paper presents an entropy-assisted adaptive CS system, whose merit is its definition of the sensed entropy without the original image. Based on sensed entropy, each image block is allocated sufficient measuring resources, guaranteeing a cost-effective reconstruction of image. Experimental results show that the proposed entropy-assisted adaptive CS system provides better objective and subjective recovery qualities with a low measuring and recovering complexity.

Enhancing the injection of electron is an effective strategy to improve the performance of polymer light-emitting diodes (PLEDs). In this work, we reported a 286% improvement in current efficiency (CE) of PLEDs by using double-layered alkali halide electron injection layer (EIL) NaCl/LiF instead of LiF. A significant enhancement of electron injection was observed after inserting the NaCl layer. To understand the mechanism of such improvement, the devices with KBr/LiF and CsF/LiF as EILs were also investigated. Experimental results show that metal cation migrated under the effect of built-in electric field (Vbi), which plays the main role on the improvement of electron injection in PLEDs.

Interface modification is an effective strategy to improve the performance of perovskite solar cells (PSCs). In this work, edible materials like glycerol and choline chloride were used to modify the surface of hole transport layer (HTL) NiOx. CH3NH3PbI3 (MAPbI3) film fabricated on the modified NiOx has a smoother surface and more uniform grains. It enables an improvement in short-circuit current density (JSC) of PSC from 17.77 ± 0.18 to 20.35 ± 0.36 mA cm−2, leading to an enhancement of power conversion efficiency from 13.37 to 15.25%. The work mechanism of glycerol and choline chloride modification was discussed. Our work provides an efficient and environmentally friendly choice for interface modification.

Organometallic halide perovskite films based on lead iodide precursor often suffered from bad repeatability and the usage of large quantities of toxic solvents due to the need for an anti-solvent washing process. Lead acetate (Pb(Ac) 2 ) precursor, by contrast, was more promising because of the needless of anti-solvent washing during the fabrication of perovskite films. However, the performance of perovskite solar cells (PSCs) needs to be improved. Here, we developed a simple strategy to improve the efficiency of PSCs by adding a small amount of dimethylsulfoxide (DMSO) into the precursor solution of perovskite. An increase in power conversion efficiency (PCE) of PSCs from 13.34% to 15.74% was achieved. It was found that with the addition of DMSO, a stable mesophase structure was formed, which significantly delayed the crystallization of perovskite during the spin-coating of precursor solution, resulting in more uniform and dense perovskite films. The trap intensity and charge carrier mobility of the perovskite films were estimated. The charge carrier dynamic and the recombination in the PSCs were studied. Our method provided a convenient way to improve the performance of PSCs based on Pb(Ac) 2 precursor.

As information-centric networking (ICN) cache can effectively reduce the requests from customers to producers and improve the efficiency of content acquisition, there are many studies propose to improve system performance of the Internet of Things (IoT) by using the concept of the ICN. In the context of information-centric IoT, the addressing location based on content names and routing transport mechanisms, which presents a high demand for the statistics and prediction of the content popularity. To improve the accuracy of the content popularity prediction, in this paper, we demonstrate a particular analysis of the content popularity and propose a content popularity prediction algorithm based on auto-regressive (AR) model. The algorithm derives regression parameters based on least-squares estimates and predicts future trends of the content popularity through combining various known values in a certain period. The evaluation results show that the proposed algorithm can accurately predict the content popularity of the next time period in information-centric IoT. As a result, the algorithm can increase the cache hit rate in routers, and reduce the network traffic and service access delay effectively to improve the experience of users in various scenarios such as real-time streaming media services.

Transition metal sulfides are cheap and efficient catalysts for water splitting to produce hydrogen, these compounds have attracted wide attention. Nickel sulfide (NiS2) has been studied in depth because of its simple preparation process, excellent performance and good stability. Here, we propose a modification to the hydrothermal synthesis method for the fabrication of a highly efficient and stable NiS2 electrocatalyst prepared by two different sulfur sources, i.e., sulfur powder and C3H7NaO3S2 (MPS), for application in hydrogen evolution reactions. The obtained NiS2 demonstrated excellent HER performance with an overpotential of 131 mV to drive -10 mA cm&minus, 1 in 0.5 M H2SO4 solution with 5mV performance change after 1000 cycles of stability testing. We believe that this discovery will promote the industrial development of nonprecious metal catalysts.

The long-lived debate on the principle of effective stress is rooted in the obscure physical significance of stresses. For the sakes of clarifying stress concepts and establishing a reasonable principle of effective stress, unsaturated soil is divided into six phases and the bearing structure of it, named generalized soil structure, is defined based on considering soil as a special structure. Then the essence of effective stress equation, named stress relation equation, is derived according to analysis of interphase interactions and independent-phase equilibrium. The stress relation equation indicates the corresponding relation between two series of stress variables used in mixed and multiphase continuum models, respectively. Furthermore, a reasonable concept of suction stress is redefined to describe interparticle connection properties. Then, a generalized stress framework is constructed by associating stress relation equation with suction stress. After demonstrating the concept of neutral stress, a generalized principle of effective stress is established and the total soil skeleton stress is searched out, which is the predominant stress controlling the strength and deformation of soil. Finally, the collapse phenomenon is analyzed and the time- and spatial-dependent stress frameworks are developed.

Cep152 and Cep63 act as the cradle and recruit Plk4 to initiate the centriole biogenesis in a mother centriole dependent manner. However, how the Cep152-Cep63 complex is targeted to the proximal end of mother centrioles is unclear. In this study, we show that Cep57 and its paralog, Cep57l1, colocalize with Cep63 and Cep152 at the proximal end of mother centrioles in both cycling cells and differentiated multiciliated cells. Both Cep57 and Cep57l1 associate with the Cep152-Cep63 complex by directly binding to the centrosomal targeting region of Cep63. Co-depletion of Cep57 and Cep57l1 blocks the loading of Cep63-Cep152 to the centriole and subsequently prevents centriole duplication. We propose that Cep57 and Cep57l1 act together to ensure the recruitment of the Cep63-Cep152 complex to the mother centrioles for procentriole formation.Summary statementCep57 and its paralog, Cep57l1, cooperatively act as a molecular scaffold to recruit the Cep63-Cep152 cradle to the proximal end of centrioles in the early stages of centriole duplication.

The Cep63-Cep152 complex located at the mother centriole recruits Plk4 to initiate the centriole biogenesis. How the complex is targeted to mother centrioles, however, is unclear. In this study, we show that Cep57 and its paralog, Cep57l1, colocalize with Cep63 and Cep152 at the proximal end of mother centrioles in both cycling cells and multiciliated cells undergoing centriole amplification. Both Cep57 and Cep57l1 bind to the centrosomal targeting region of Cep63. The depletion of both proteins, but not either one, blocks the loading of Cep63-Cep152 complex to mother centrioles and consequently prevents centriole duplication. We propose that Cep57 and Cep57l1 function redundantly to ensure the recruitment of the Cep63-Cep152 complex to the mother centrioles for procentriole formation.

Enhancing the injection of electron is an effective strategy to improve the performance of polymer light-emitting diodes (PLEDs). In this work, electron injection was improved by inserting sodium compounds NaCl, NaBr, NaI and Na2CO3, respectively, between emissive layer (EML) and electron injection layer (EIL). A maximum 49.6% increase in current efficiency (CE) of PLEDs from 10.85 to 16.24 cd/A was achieved based on NaCl. The Vbi values of PLEDs were investigated to analyze the performance enhancement of PLEDs, which can be ascribed to the migration of Na+. The effect of NaCl, NaBr, NaI and Na2CO3 on the performance of PLEDs were compared to investigate the influence of the anion of sodium compounds. Our work provides an effective and simple method to improve the performance of PLEDs, which is also compatible with the roll-to-roll technology.

Image compressive sensing (CS) is a potential imaging scheme for green internet of things (IoT). To further make CS-based sensor adaptable to low bandwidth and low power, this paper focuses on finding a good measurement structure, i.e., the organization and storage format of CS measurements. Three potential measurement structures are proposed in this paper, respectively raster structure (RA), patch structure, and layer structure (LA). RA stores CS measurements of each column in an image, and PA packets CS measurements of overlapping patches forming an image. LA enables the measuring of small blocks and recovery of large blocks. All of the three structures avoid high computation complexity and huge memory in the process of measuring and recovery, and efficiently suppress the annoying blocking artifacts which often occur in traditional block structures. Experimental results show that RA, PA, and LA can efficiently reduce blocking artifacts, and produce comforting visual qualities. LA, especially, presents both good time-distortion and rate-distortion performance. By this paper, it is proved that LA is a suitable measurement structure for green IoT.

Based on the full performance test data of a large number of smart meters, a performance evaluation method for smart meters based on grey correlation analysis is proposed, aiming at the situation that lack of quality evaluation of smart meters in China. In this paper, six sets of representative test data of smart meters are selected as performance evaluation indexes. First, correlation analysis is used to demonstrate the independence between evaluation indexes. For each index, the weight value of different test points are obtained by principal component analysis, thus the evaluation index matrix is acquired. Then grey relational analysis is applied to construct the performance evaluation model on the basis of evaluation index matrix. Subsequently the performance evaluation results of samples can be aquired. At last, smart meter test data from three different random manufacturers were selected to prove this method. Considering the historical statistics of the field failure rate and expert opinion for each manufacturer, the evaluation results using this method are reasonable, thus this performance evaluation method for smart meters is reliable.

In this paper, we propose a measurement allocation to reduce the blocking artifacts existing in the Block Compressive Sensing (BCS) system of image. We compute the error between each image block and its adjacent ones, and evaluate the structure complexity of each block. According to the error energy, each block is adaptively measured and reconstructed. Experimental results show that the proposed method improves the qualities of reconstructed images from both subjective and objective points of view when compared with BCS of image.

Compressive Sensing (CS) realizes a low-complex image encoding architecture, which is suitable for resource-constrained wireless sensor networks. However, due to the nonstationary statistics of images, images reconstructed by the CS-based codec have many blocking artifacts and blurs. To overcome these negative effects, we propose an Adaptive Block Compressive Sensing (ABCS) system based on spatial entropy. Spatial entropy measures the amount of information, which is used to allocate measuring resources to various regions. The scheme takes spatial entropy into consideration because rich information means more edges and textures. To reduce the computational complexity of decoding, a linear mode is used to reconstruct each block by the matrix-vector product. Experimental results show that our ABCS coding system provides a better reconstruction quality from both subjective and objective points of view, and it also has a low decoding complexity.

In tension and compression of polymers, some abnormal phenomena of volume changes were often observed and its mechanism is still unclear. In this paper, based on the thermodynamics principle, it is shown that the combined effects of internal energy and entropy are the basic reason of causing the anomaly in polymers. Moreover, to describe the complicated deformation through a simple model and have a correct modelization of mechanical behaviors, a volume strain model is presented, in which the variation of volume strain resulted from the combined effects is characterized through a fractional integral expression. Comparison between fitting results and experimental results reveals the proposed model can describe the volume deformation of polymers.

There is the complex relationship between Poisson's ratio and time in viscoelastic solids. Hence, using a simple model to characterize accurately the viscoelastic Poisson's ratio is important for the analysis of viscoelastic behaviors. We put forward two deformation elements, fractional and spring deformation element, and obtain three fractional deformation models through connecting the two deformation elements in parallel or series. The functions of viscoelastic Poisson's ratio are also derived for stress relaxation and constant-longitudinal-strain loading. Further comparisons between tests and fitting results reveal that the fractional deformation models can represent reasonably the viscoelastic Poisson's ratio.

In order to describe the strain of viscoelastic materials better, a new strain model based on fractional order calculus is presented. The fractional longitudinal-transverse strain relationship and the fractional volume strain model are obtained, and the corresponding equations under a constant longitudinal strain rate loading are derived. The new models enjoy the advantage of having fewer parameters and simple form. The fractional strain model is verified by a series of tests under a constant longitudinal strain rate. It’s found that the new model can describe not only the volume strain phenomenon of polymer but also the phenomenon of negative and positive dilatancy in geomaterials.

Using a simple model to represent the complex relationship between longitudinal and transverse deformation is of much importance for a correct modelization of mechanical behaviors in viscoelastic solids. In this paper, a time-based fractional longitudinal–transverse strain model is presented based on the analogy with fractional stress–strain equation. Experimental results of a series of uniaxial compression and tension tests under strain-relaxation and constant longitudinal strain rate are employed to validate the proposed model. It is shown that the fractional longitudinal–transverse strain model can accurately describe the experimental response, and the fractional order may be positive or negative, which is helpful to characterize the complicated longitudinal–transverse deformation relationship.

Flowering plant sperm cells transcribe a divergent and complex complement of genes. To examine promoter function, we chose an isopentenyltransferase gene known as PzIPT1. This gene is highly selectively transcribed in one sperm cell morphotype of Plumbago zeylanica, which preferentially fuses with the central cell during fertilization and is thus a founding cell of the primary endosperm. In transgenic Arabidopsis (Arabidopsis thaliana), PzIPT1 promoter displays activity in both sperm cells and upon progressive promoter truncation from the 5'-end results in a progressive decrease in reporter production, consistent with occurrence of multiple enhancer sites. Cytokinin-dependent protein binding motifs are identified in the promoter sequence, which respond with stimulation by cytokinin. Expression of PzIPT1 promoter in sperm cells confers specificity independently of previously reported Germline Restrictive Silencer Factor binding sequence. Instead, a cis-acting regulatory region consisting of two duplicated 6-bp Male Gamete Selective Activation (MGSA) motifs occurs near the site of transcription initiation. Disruption of this sequence-specific site inactivates expression of a GFP reporter gene in sperm cells. Multiple copies of the MGSA motif fused with the minimal CaMV35S promoter elements confer reporter gene expression in sperm cells. Similar duplicated MGSA motifs are also identified from promoter sequences of sperm cell-expressed genes in Arabidopsis, suggesting selective activation is possibly a common mechanism for regulation of gene expression in sperm cells of flowering plants.