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Lithium sulfur batteries (LSBs) with high energy density hold some promising applications in the wearable and flexible devices. However, it has been still challenging to develop a simple and feasible approach to prepare flexible LSB cathodes with both robust mechanical strength. Herein, flexible S@C-CNTs cathodes with controllable thicknesses are successfully fabricated via a facile blade-coating method. Due to the strong cohesion among CNTs bundles and the well-designed structure, the flexible S@C-CNTs cathodes are demonstrated to be with a combination of impressive mechanical strength and enhanced electrochemical performance. For the flexible S@C-CNTs cathodes with the sulfur mass loading of 4 mg cm−2, the areal capacity is close to 3.0 mA h cm−2, and the breaking stress is up to 5.59 MPa with 7.77% strain. Meanwhile, the pouch cell exhibits excellent cyclic stability at both flat/bent conditions. All demonstrate that the flexible S@C-CNTs cathodes may satisfy the demands of practical application. Moreover, this methodology is suitable for designing other flexible battery electrodes, such as flexible Si@C-CNTs anodes for lithium ion batteries, flexible P@C-CNTs anodes for sodium/potassium ion batteries, etc.

Herein, a series of novel Na2GdMg2(VO4)3:Eu3+ (NGMVO:Eu3+) red phosphors were elaborated by conventional solid-state reaction process. Their structural features, luminescent properties, energy transfer were researched at length. XRD patterns indicate that NGMVO:Eu3+ crystallized in single cubic garnet structure. Under the excitation of near ultraviolet light at 356 nm, the emission spectra of NGMVO host could be divided in two parts that resulted from 3T2 → 1A1 and 3T1 → 1A1 transitions of VO43−. While NGMVO:Eu3+ phosphors show intense sharp red emission peaks including 590, 610, 652 and 706 nm that originated from 5D0 → 7FJ (J = 1–4) transitions of Eu3+, respectively. The optimal concentration of Eu3+ is 0.7. Importantly, NGMVO:0.7Eu3+ sample presents high energy transfer efficiency (89 %) and high external quantum efficiency (48.3 %). Besides, its emission intensity remains 79 % at 420 K compared with that at 300 K, proving the good thermal stability of phosphors. All above results suggest that NGMVO:Eu3+ red phosphors have latent applications in white light emitting diodes.

For grain combine harversters the correlation between cutting frequency and forward speed is typically based on the theoretical matching value of the cutting pattern. However, in reality cutting frequency is affected by cutting resistance which strongly linked to the physical and mechanical characteristics of the crop stems. Consequently, the field cutting frequency is usually lower the standard setting, resulting in the possibility of increasing losses during harvesting. An optimal cutting frequency model was built firstly based on the cutting pattern but the influencing factors on cutting frequency was analysed, and then a relationship model between cutting energy and cutting frequency was built. A regression model of the influence of wheat stem moisture content and cutting section area on cutting frequency was established by wheat stem cutting experiments. Thus, a cutting frequency compensation control strategy was proposed. To verify the effectiveness of the control strategy, field tests were carried out on uniformly growing wheat fields. The results showed that at the forward speeds of 1 m s−1 and 1.5 m s−1, the maximum deviation between the cutting frequency determined by this proposed approach and the optimal cutting frequency were 0.47 Hz and 1.1 Hz, respectively. Comparing performance without this compensation model, the maximum deviation of the cutting frequency without compensation decreased by 28.33% and 24.60%, respectively. The results indicated that with the proposed approach, the maximum deviation between the field cutting frequency and the predicted optimal cutting frequency could be significantly decreased and the cutting performance of the combine harvester could be observably improved.

Thermal risk analysis is essential for the development of chemical reactions. This work should be carried out on the basis of a thorough comprehension of the reaction mechanism. In this article, th...

Thermal runaway of chemical reactions often lead to secondary decomposition of the material, especially with autocatalytic decomposition characteristics. Autocatalytic decompositions are often characterized by drastic decomposition, intense heat release, high thermal risk and difficultly in control. Quantitative classification of different autocatalytic strengths is significant for the formulation of risk control measures and recognition of the most dangerous scenarios in relief system. In this work, the factor, which is the ratio of the heat released by the initial stage to that of the total reaction, has been defined to effectively and quantitatively assess the strength of autocatalytic decomposition based on the Perez-Benito model that includes two-stage competitive reactions. According to “3σ principle” of the normal distribution, the factor was classified into five grades: 0–5%, 5–18%, 18–82% 82–95%, 95–100% corresponding to the autocatalytic strength: strong, less strong, moderate, less weak and weak, respectively. This method is validated using cumyl hydro-peroxide and dicumyl peroxide, the autocatalytic strength of which are well known to be less strong (7.92%) and weak (100%), respectively. The results are consistent with the profile width, heat-quench-reheat test and the isothermal tests. This method was used to classify the autocatalytic strength of dimethyl sulfoxide, 29.5 mass% nitro-guanidine aqueous solution, and Benz aldoxime. The results show that the autocatalytic strengths of these three materials are strong (0.01%), moderate (31.52%) and less weak (82.67%), respectively. Through the classification assessment, it helps to get a more intuitive understanding of the degree of substance danger from the perspective of kinetics and thermodynamics.

As a major high-energy plasticizer in the production of propellant, the destructive nature and thermal hazards of DINA are enormous. To evaluate the potential thermal hazards for its decomposition, the non-isothermal DSC and ARC experiments were performed to determine the decomposition kinetic model and parameters. It can be seen from the DSC results that DINA underwent a melting process before thermal decomposition, the endothermic peak and exothermic peak are identified at about 49−52℃ and 153−162℃, respectively. Combined with the results of DSC and ARC tests, the reliable kinetic model of DINA consists of four consecutive autocatalytic reaction has been created and verified. Subsequently, kinetic-based numerical simulations were executed to evaluate the thermal explosion hazards of DINA under the different scenarios. Process safety parameters under adiabatic conditions including time to maximum rate as well as induction period were consequently retrieved. Furthermore, inherent safety recommendations were proposed to forestall the process accidents in storage and the applications of DINA.

Herein, Na2YMg2(VO4)3:Er3+,Yb3+ phosphors are reported for up-conversion (UC) luminescent material as optical thermometry relied on fluorescence intensity ratio (FIR) and fluorescence lifetime. Their structures, UC luminescent properties and temperature sensing properties have been systematically investigated. Heavy doping of Er3+ and Yb3+ ions with maximal content of 59% is realized, which is beneficial to obtain highly efficient UC luminescence. Excited by 980 nm laser, Er3+ and Er3+,Yb3+ doped phosphors give 525, 550 and 660 nm emissions, which are originated from 2H11/2, 4S3/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. The reasonable UC mechanism is discussed in detail. What's more, the UC emissions of all samples dominate in green area from thermally coupled 2H11/2/4S3/2 levels of Er3+ ions, which is helpful to obtain better temperature sensing performances. And the maximal relative sensitivities of FIR and fluorescence lifetime methods reach 1.104 %K−1 (303 K) and 0.087 %K−1 (412 K), respectively. All results manifest that Na2YMg2(VO4)3:Er3+,Yb3+ phosphors are good potential alternative for optical temperature sensors.

To ensure boom sprayer safety and spraying efficiency, the sprayer boom height must be adjusted during pesticide application. The field variation characteristics of the sprayer boom height are the basis of the boom balance adjustment. A boom height detection system based on ultrasonic sensors was designed. Field tests were performed in 2.0 ha of vacant fields and 13.44 ha of wheat stubble fields. A signal processing method based on the K-means clustering algorithm was used to preprocess the ultrasonic sensor data. The results showed that the K-means clustering algorithm could effectively improve the detection accuracy of an ultrasonic sensor. The boom height variation was greatest at the sides of the boom, and the primary frequencies of the boom height variation were concentrated within a low-frequency band from 0 Hz to 1 Hz. The U-turn operation was more likely to cause the boom to contact the crop canopy or the ground than row operation. As the spraying speed increased, the maximum boom height variation and maximum roll angle increased; these primary components decreased in frequency, and the amplitude clearly increased. The maximum boom height variation exceeded 50 cm, and the maximum roll angle exceeded 3°, which not only aggravated the droplet drift but also caused damage to the boom and nozzles due to contact with the ground or the crop canopy. These findings can provide a theoretical basis for use in the development of an automatic boom height adjustment system.

A new type of Bi3+,Eu3+ single- and co-doped Na3.6Y1.8(PO4)3 phosphate phosphors were manufactured using conventional high-temperature solid-state reaction technique to explore their application for solid-state lighting. The crystal structure, luminescent properties, luminescent mechanism and quantum efficiency were thoroughly explored. Results show that there are two crystallization sites for Bi3+ and Eu3+ ions. Upon the excitation of 342 and 373 nm, Bi3+ single-doped phosphors exhibit green and blue emission, derived from the 3P1 to 1S0 transition of Bi3+ located in different occupancy sites. Thanks to radiative energy transfer process from Bi3+ to Eu3+, adjustable emission could be acquired by altering Eu3+ content in co-doped phosphors. Pure white-light emission with quantum efficiency value of 22.9% can be realized in Na3.6Y1.8(PO4)3:0.01Bi3+,0.1Eu3+ sample and the integrated intensity of white light emission at 417 K remains 85% of that at room temperature. Our results indicate that Na3.6Y1.8(PO4)3:Bi3+,Eu3+ phosphors have feasible application in high-power ultraviolet driven solid-state lighting.

Food adulteration often results in consumer distrust and unfair commercial competition. Traded form of raw material powder from health food is vulnerable to adulteration; therefore, an effective method for detection and qualitative analysis for powder products is necessary. This study aimed to develop, optimize, and validate an accurate identification and quantification approach based on droplet digital PCR (ddPCR) to determine Panax notoginseng (P. notoginseng) main root powder for quality control of P. notoginseng; a popular raw material for health food. Diacylglycerol kinase 1 gene, a single-copy nuclear gene was selected, and P. notoginseng-specific primers and probe were designed. An equation for determining the weight of P. notoginseng powder based on DNA copy number was established with DNA concentration as a conversion factor. The accuracy of ddPCR was demonstrated by analyzing the mixed powder samples with the known composition of P. notoginseng powder. To verify the applicability of the method, commercially available products were detected. The results indicated that the developed ddPCR assay is highly precise and suitable for the qualitative and quantitative analysis of P. notoginseng powder. Overall, this new analytical approach can be a useful tool for quality control of P. notoginseng powder.

Multiphase catalysis is used in many industrial processes; however, the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water, especially for oxygen-dependent biocatalytic reactions. Despite the fact that solubility and diffusion rates of oxygen in many liquids (such as perfluorocarbon) are much higher than in water, multiphase reactions with a second liquid phase are still difficult to conduct, because the interaction efficiency between immiscible phases is extremely low. Herein, we report an efficient triphase biocatalytic system using oil core–silica shell oxygen nanocarriers. Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion. Moreover, the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation. Using oxygen-dependent oxidase enzymatic reaction as an example, we demonstrate this efficient biocatalytic system for the oxidation of glucose, choline, lactate, and sucrose by substituting their corresponding oxidase counterparts. A rate enhancement by a factor of 10–30 is observed when the oxygen nanocarriers are introduced into reaction system. This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.

It was demonstrated recently that ideal capacitors can not exist physically and that the behavior of real-world inductors and capacitors is characterized by fractional-order (FO) models. Therefore, the modeling and analysis of FO electrical circuit networks (FO-ECN) has gained considerable interest. This paper introduces the basic principles of a class of rectangular prism n-units () RLC FO-ECN, including the mathematical modeling and the analysis of the impedance magnitude and phase. Three general formulas of the equivalent impedance between two nodes of the FO-ECN are obtained by the matrix transform method. The relationship between the impedance and the FO-ECN parameters, including the capacitance, inductance, number of circuit units and FO are investigated. Numerical simulations reveal dynamical phenomena not exhibited by ordinary ECN., This work was supported by the National Natural Science Funds of China (No. 11971032).

In view of time delay in the transport of nutrients, a delayed reaction-diffusion system with homogeneous Neumann boundary conditions is presented to understand the formation of the heterogeneous distribution of bacteria and nutrients in the sediment. With the effects of time delay and diffusion, the system will experience various dynamical behaviors, such as stability, the Turing instability, successive switches of stability of equilibria, the Hopf and the Hopf-Hopf bifurcations. To further understand the dynamics of the Hopf-Hopf bifurcation, the multiple time scale (MTS) technique is employed to derive the amplitude equations at this co-dimensional bifurcation point, and the dynamical classification near such bifurcation point is also identified by analyzing the obtained amplitude equations. Some numerical simulations are carried out to demonstrate the validity of the theoretical analysis.

The time-domain approximation of the Grünwald–Letnikov fractional derivative is intuitive and widely adopted in the design of fractional-order proportional-integral (FOPI) controllers. To solve the accuracy reduction caused by truncating the series, an optimized discrete FOPI is presented. The effectiveness of the new FOPI is highlighted and compared with the one exhibited by a controller implemented based on the Oustaloup method. Furthermore, to improve the performance of the FOPI, a variable-order fractional proportional-integral (VFPI) controller is proposed. The response of the VFPI is verified in the control of a permanent magnet synchronous motor. Simulation and experimental results show the superior performance of the VFPI., The authors would like to express their deep gratitude to the Editors and the anonymous referees for their helpful comments and suggestions, which have greatly improved the paper. This work was supported by the National Natural Science Funds of China (No. 11971032), the Fundamental Research Funds for the Central Universities (No. JZ2019HGTB0090), Ministry of Education China Mobile Research Fund (MCM20180404) and Chongqing Basic Research and Frontier Exploration Project (cstc2018jcyjAX0167).

The decomposition of many hazardous materials goes through autocatalytic mechanisms. Due to the unpredictably sudden heat evolution companied with the decomposition of these materials, it is of great importance to identify autocatalytic decompositions and treat them with caution. In this work, a kinetic-parameters-free criterion is proposed to determine the autocatalytic decomposition using adiabatic calorimeters. This criterion states that the decompositions are autocatalytic if the values of R T p 2 T f − T p obtained by adiabatic experiments in different conditions are variable; otherwise they follow n-order behavior. Mathematical simulations at different values of φ, α0 and Ton have been conducted for n-order and autocatalytic decompositions to validate the criterion. To further validate the criterion, this method is applied to four representative substances: DCP, 20 % DTBP in toluene, BO and CHP. Overall, the validity of this criterion has been verified by simulation and experiment results.

High accuracy on-line estimation for fruit internal quality is still a challenge due to varying geometric structures and orientations. In this study, multiple full-transmittance spectra were collected using short-integration-time mode for each apple. The signal-to-noise ratio of each collected spectrum changed with the measurement position of the fruit due to the heterogeneity of internal composition. To explore the distribution character of transmittance spectra across the apple structure to guide the development of an on-line fruit quality determination system, a methodology which we called ‘zone combination modelling’ was proposed for selecting the most effective spectra for SSC prediction. The orientation of stem–calyx axis vertical was selected as the preferred orientation for quality prediction of ‘Fuji’ apple based on the analysis of the variation and quality of full-transmittance spectra. The most ineffective and most effective zone combinations for SSC prediction were determined by investigating the effect of transmittance spectra within different zone combinations on SSC prediction ability. Ten effective wavelengths selected from the most efficient zone combination were used to develop an optimal prediction model. Results showed that the contribution of different spectral measurement zones to SSC prediction capability varied and that in particular, those collected from the apple core zone should be removed when building SSC prediction models. The coefficient of determination and root mean square errors of prediction and validation sets of SSC, respectively, were 0.733 and 0.61%, 0.721 and 0.71% for the optimal model, indicating that zone combinations model was promising for SSC prediction of apple.

Leaf senescence is driven by the expression of senescence-associated genes (SAGs). Development-specific genes often undergo DNA demethylation in their promoter and other regions, which regulates gene expression. Whether and how DNA demethylation regulates the expression of SAGs and thus leaf senescence remain elusive. Whole-genome bisulfite sequencing (WGBS) analyses of wild-type (WT) and demeter-like 3 (dml3) Arabidopsis leaves at three developmental stages revealed hypermethylation during leaf senescence in dml3 compared with WT, and 20 556 differentially methylated regions (DMRs) were identified by comparing the methylomes of dml3 and WT in the CG, CHG, and CHH contexts. Furthermore, we identified that 335 DMR-associated genes (DMGs), such as NAC016 and SEN1, are upregulated during leaf senescence, and found an inverse correlation between the DNA methylation levels (especially in the promoter regions) and the transcript abundances of the related SAGs in WT. In contrast, in dml3 the promoters of SAGs were hypermethylated and their transcript levels were remarkably reduced, and leaf senescence was significantly delayed. Collectively, our study unraveled a novel epigenetic regulatory mechanism underlying leaf senescence in which DML3 is expressed at the onset of and during senescence to demethylate promoter, gene body or 3′ UTR regions to activate a set of SAGs.

Highly sensitive and selective detection of DNA adenine methylation methyltransferase (Dam MTase) activity is essential for clinical diagnosis and treatment as Dam MTase can catalyze DNA methylation and has a profound effect on gene regulation. In this study, a fluorescence biosensor has been developed for label-free detection of Dam MTase activity via methylation-sensitive cleavage primers triggered hyperbranched rolling circle amplification (HRCA). A hairpin DNA probe (HP) with a Dam MTase specific recognition sequence on the stem acting as a substrate has been designed. This substrate probe can be methylated by the target in the system and subsequently cleaved by DpnI, which results in the release of the primer release probe (RP) and hence in turn triggers the subsequent HRCA reaction. As the HRCA products contain many double-strand DNA (dsDNA) with different lengths, and the SYBR Green I can be embedded in the dsDNA to produce a strong fluorescence signal. However, in the absence of the target, the presence of the probe HP in the form of a hairpin cannot induce the HRCA reaction, and only weak fluorescence intensity can be detected. Under the optimized conditions, the fluorescence of the system has a linear relationship with the logarithm of the concentration of Dam MTase in the range of 2.5–70 U/mL with a detection limit of 1.8 U/mL. The Dam MTase can be well distinguished from other MTase analogs. The developed sensor was applied to detect target in serum and E. coli cell lysate, and the standard recovery rates were in the range of 96%–105%. The results showed that this method has great potential for assessing Dam MTase activity in complex biological samples. In addition, the method has been applied to detect the related inhibitors with high efficiency.

A novel color image encryption algorithm based on dynamic deoxyribonucleic acid (DNA) encoding and chaos is presented. A three-neuron fractional-order discrete Hopfield neural network (FODHNN) is employed as a pseudo-random chaotic sequence generator. Its initial value is obtained with the secret key generated by a five-parameter external key and a hash code of the plain image. The external key includes both the FODHNN discrete step size and order. The hash is computed with the SHA-2 function. This ensures a large secret key space and improves the algorithm sensitivity to the plain image. Furthermore, a new three-dimensional projection confusion method is proposed to scramble the pixels among red, green, and blue color components. DNA encoding and diffusion are used to diffuse the image information. Pseudo-random sequences generated by FODHNN are employed to determine the encoding rules for each pixel and to ensure the diversity of the encoding methods. Finally, confusion II and XOR are used to ensure the security of the encryption. Experimental results and the security analysis show that the proposed algorithm has better performance than those reported in the literature and can resist typical attacks.

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells have drawn worldwide attention for their promising photovoltaics performance and earth-abundant element composition, yet the record efficiency of this type of device is still far lower than its theoretical conversion efficiency. Undesirable band alignment and severe non-radiative recombination at CZTSSe/CdS heterojunction interfaces are the major causes limiting the current/voltage output and overall device performance. Herein, we propose a novel two-step CdS deposition strategy to improve the quality of CZTSSe/CdS heterojunction interface and thereby improve the performance of CZTSSe solar cell. The two-step strategy includes firstly pre-deposits CdS thin layer on CZTSSe absorber layer by chemical bath deposition (CBD), followed with a mild heat treatment to facilitate element inter-diffusion, and secondly deposits an appropriate thickness of CdS layer by CBD to cover the whole surface of pre-deposited CdS and CZTSSe layers. The solar energy conversion efficiency of CZTSSe solar cells with two-step deposited CdS layer approaches to 8.76% (with an active area of about 0.19 cm2), which shows an encouraging improvement of over 87.98% or 30.16% compared to the devices with traditional CBD-deposited CdS layer without and with the mild annealing process, respectively. The performance enhancement by the two-step CdS deposition is attributed to the formation of more favorable band alignment at CZTSSe/CdS interface as well as the effective decrease in interfacial recombination paths on the basis of material and device characterizations. The two-step CdS deposition strategy is simple but effective, and should have large room to improve the quality of CZTSSe/CdS heterojunction interface and further lift up the conversion efficiency of CZTSSe solar cells.

The height to crown base (HCB) of a tree is a necessary variable that includes many growth and yield models as a predictor, and it is important to develop an HCB model due to its contribution to fo...

Graphene has been studied extensively owing to its excellent lubricity performance. However, when used as lubricant additives, graphene layers tend to agglomerate and precipitate; further, poor dispersion will reduce the lubrication performance. Herein, graphene was evenly dispersed in Triton X-100/1-alkyl-3-methylimidazole ditrifluorosulfonylimide (CnmimNTf2)/H2O (n = 8, 12, and 16) lamellar liquid crystals (LLCs). The effects of the graphene concentration on the microstructures of the LLCs are detected by 2H NMR and small angle X-ray scattering measurements and their rheological and tribological performance are investigated in detail. The addition of 0.30 mg mL−1 graphene into the Triton X-100/C16mimNTf2/H2O LLC system led to a 15% reduction in the friction coefficient and 65% reduction in the wear volume when compared with the pure LLCs. The synergistic effect of the graphene and LLC hybrid system efficiently improved the lubrication performance, which is attributed to the higher order of the amphiphilic molecules and the thicker amphiphilic bilayer. The generated tribofilm formed by the physical adsorption and the tribochemical reaction of LLCs on the surface of steel is conducive to lubricity protection from abrasion. This study reveals that with the understanding of the microstructure change mechanism, the combination of graphene and LLCs could provide a new path to the design of a novel lubricant that can be utilized in nanostructures for energy saving applications.

Developing low-cost and high-efficiency bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is pivotal for large-scale production of clean and sustainable hydrogen energy, but still remains challenging. In this work, a facile strategy to construct the VOOH/Ti3C2Tx MXene heterostructures is reported, benefiting from the optimized electronic structure and abundant heterogeneous interfaces that weakens the adsorption of oxygen-containing intermediates, as well as accelerating the dissociation of water molecules, thus facilitating the catalytic kinetics of the OER and HER. As expected, the VOOH/Ti3C2Tx MXene required overpotentials of 238 mV for the OER and 100 mV for the HER to reach a current density of 10 mA cm−2. More importantly, by employing the VOOH/Ti3C2Tx MXene as both the anode and the cathode, a two-electrode alkaline electrolyzer delivers a current density of 10 mA cm−2 at a low cell voltage of 1.579 V, which is superior to the commercial IrO2‖Pt/C couple. This work opens up appealing opportunities for the rational design of MXene-based hybrid materials for efficient H2 production and other energy-related applications.

A visible-light catalyzed [3 + 1 + 2] annulation for the synthesis of unsymmetrical trisubstituted amino-1,3,5-triazines from amidines, isothiocyanates, and 1,1,3,3-tetramethylguanidines has been developed. This method exhibits the advantages of easily available starting materials, insensitive to air and moisture, wide substrate scopes, high step economy, mild, metal- and ligand-free conditions, which has potential applications in the organic, medicinal, and material chemistry.

The smooth representation (SMR) model is a widely used segmentation method in computer vision. This model adopts the K nearest neighbour (KNN) graph to select samples for representation. All neighbours in the KNN graph are assumed to be equally important candidates. In this paper, we use special weights that are calculated by a novel cross-view kernel function to evaluate the contributions of neighbours to the subspace clustering in SMR. The neighbours that are found by the Gaussian similarity formula can be considered long-range similar neighbours. We add another item to accurately reflect the order relation in the cross-view kernel function. This addition allows the kernel function to generalize the conventional SMR method for sequential data. The ordered smooth representation (OSMR) model outperforms other representative space clustering methods on public datasets, namely, the UCI database, the USPS database, Yale B datasets, the Freiburg–Berkeley Motion Segmentation database and a real-world mobile video that was captured by a smart phone.

Spatiotemporal dynamics of a ratio-dependent predator-prey model with time delay and the Neumann boundary condition are considered. The existence of the codimension-two Turing–Hopf bifurcation point is proved, so that both the Turing and Hopf bifurcations will occur simultaneously. Then, through the global Hopf bifurcation results, the global Hopf bifurcation of the ratio-dependent predator-prey model is investigated when diffusion is absent. Further, to identify the spatiotemporal dynamics during the Turing–Hopf bifurcation, the method of the multiple time scale analysis is employed to derive the amplitude equations near the codimension-two bifurcation point, instead of employing the center manifold theory and the normal form reduction. By analyzing the amplitude equations, it is found that the original ratio-dependent predator-prey model may exhibit the spatial, temporal or the spatiotemporal patterns, such as the nonconstant steady state, spatially homogeneous periodic solutions as well as the spatially inhomogeneous periodic solutions. Numerical simulations are carried out to validate the theoretical results.

N-Nitrodiethanolamine dinitrate (DINA) is a nitramine explosive containing both O-nitro and N-nitro groups. In this work, the synthesis of DINA by nitration of diethanolamine hydrochloride (DEAHC) ...

WSL8 encoding a deoxyribonucleoside kinase (dNK) that catalyzes the first step in the salvage pathway of nucleotide synthesis plays an important role in early chloroplast development in rice. The chloroplast is an organelle that converts light energy into chemical energy; therefore, the normal differentiation and development of chloroplast are pivotal for plant survival. Deoxyribonucleoside kinases (dNKs) play an important role in the salvage pathway of nucleotides. However, the relationship between dNKs and chloroplast development remains elusive. Here, we identified a white stripe leaf 8 (wsl8) mutant that exhibited a white stripe leaf phenotype at seedling stage (before the four-leaf stage). The mutant showed a significantly lower chlorophyll content and defective chloroplast morphology, whereas higher reactive oxygen species than the wild type. As the leaf developed, the chlorotic mutant plants gradually turned green, accompanied by the restoration in chlorophyll accumulation and chloroplast ultrastructure. Map-based cloning revealed that WSL8 encodes a dNK on chromosome 5. Compared with the wild type, a C-to-G single base substitution occurred in the wsl8 mutant, which caused a missense mutation (Leu 349 Val) and significantly reduced dNK enzyme activity. A subcellular localization experiment showed the WSL8 protein was targeted in the chloroplast and its transcripts were expressed in various tissues, with more abundance in young leaves and nodes. Ribosome and RNA-sequencing analysis indicated that some components and genes related to ribosome biosynthesis were down-regulated in the mutant. An exogenous feeding experiment suggested that the WSL8 performed the enzymic activity of thymidine kinase, especially functioning in the salvage synthesis of thymidine monophosphate. Our results highlight that the salvage pathway mediated by the dNK is essential for early chloroplast development in rice.

The development of a rodent ambient particulate matter (PM) inhalation system is critical for drawing causal inferences between PM exposure and the onset of human diseases. In this study, we constructed a real-ambient PM exposure system to investigate multi-organ injury and the reversibility of the impairments in C57BL/6 J male mice exposed to PM with a duration of up to three months in Shijiazhuang, a city with the highest PM2.5 concentration in China. This unique exposure system provided an optimal scenario for round-the-clock PM exposure absent a change in the physiochemical properties of PM and minimized the disturbance to the mice habitat. The mean concentration of PM2.5 in the exposure chambers was 89.95, 79.98, and 87.87 μg/m3 at three different time points, respectively: weeks 1–3, week 1–6, and week 1–12. The injury in multiple organs, including lung, brain, heart, testis, and intestine, was profound and was evident by the significant pathological and functional alterations. Pulmonary pathological examination revealed severe interstitial inflammatory and alveolar hemorrhage throughout the exposure, which was in line with the reduced lung function and the increased cytokine excretion in bronchoalveolar lavage fluid and blood plasma. Notably, the PM-mediated inflammatory response in different systems was correlated with the severity of the injury and the attenuation of pulmonary lesions in the recovery group. Thus, the PM2.5-induced inflammatory response, the chemical components-induced cytotoxicity, genetic damage, and oxidative stress might be implicated in the impairment of multiple murine organs. These findings revealed the severity, sensitivity, and reversibility of multi-organ injury in response to a real-ambient PM exposure.

As NF-κB signaling pathway is constitutively activated in lung cancer, targeting NF-κB has a potential for the treatment. EF24 has been proved to be a NF-κB inhibitor with good antitumor activity, while whose toxicity possibly became one of the obstacles to enter into clinical application. In order to find high efficiency and low toxicity NF-κB inhibitors, EF24 was modified and 13d was screened out. It was proved that 13d possessed an effective combination of inhibiting NF-κB pathway and showing lower cytotoxicity on normal cells as well as less toxicity in acute toxicity experiment compared with the lead compound of EF24. In addition, 13d was found to inhibit cell vitality, arrest cell cycle in G2/M phase, promote cell apoptosis, and suppress the xenograft tumor growth. Furthermore, 13d was elucidated to induce pyroptosis developing from apoptosis, which was associated with the inhibition of NF-κB. Taken together, it was suggested that 13d was a potent antitumor agent.

To promote the practical application of CL-20/HMX co-crystal, the understanding of its thermal decomposition kinetics and thermal hazard prediction are highly required. In this study, the kinetic model was evaluated based on the non-isothermal DSC data by using non-linear optimization method, which was identified as a complicated reaction comprising two parallel autocatalytic paths, and the contribution of the two reaction paths was revealed to vary depending on the heating rate. Based on the kinetic model, the thermal hazard simulation indicates that the temperature when the occurrence of thermal decomposition after 24 h (Td,24) of CL-20/HMX co-crystal is 151.64 °C, and the critical temperature of 1000th second explosion is determined as ˜196 °C. Besides, simulation results of self-accelerating decomposition temperature demonstrate that the package mass of CL-20/HMX co-crystal, rather than the package material, has a remarkable effect on the thermal safety of CL-20/HMX co-crystal.

Dendrobium officinale is a traditional medicinal herb with a variety of bioactive components. Alkaloid is one of the major active ingredients of Dendrobium plants, and its immune regulatory effects have been well-studied. Although a number of genes involved in the biosynthetic pathway of alkaloids have been elucidated, the regulation mechanism underlying the methyl-jasmonate (MeJA)-induced accumulation of alkaloids in D. officinale is largely unknown. In our study, a total of 4,857 DEGs, including 2,943 up- and 1,932 down-regulated genes, were identified between the control and MeJA-treated groups. Kyoto Encyclopedia of Genes and Genomes annotation showed that a number of DEGs were associated with the putative alkaloid biosynthetic pathway in D. officinale. The main group of Dendrobium alkaloids are sesquiterpene alkaloids, which are the downstream products of mevalonate (MVA) and methylerythritol 4-phosphate (MEP) pathway. Several MVA and MEP pathway genes were significantly up-regulated by the MeJA treatment, suggesting an active precursor supply for the alkaloid biosynthesis under MeJA treatment. A number of MeJA-induced P450 family genes, aminotransferase genes and methyltransferase genes were identified, providing several important candidates to further elucidate the sesquiterpene alkaloid biosynthetic pathway of D. officinale. Furthermore, a large number of MeJA-induced transcript factor encoding genes were identified, suggesting a complex genetic network affecting the sesquiterpene alkaloid metabolism in D. officinale. Our data aids to reveal the regulation mechanism underlying the MeJA-induced accumulation of sesquiterpene alkaloids in D. officinale.

Anisotropy photoresponse can be effectively achieved based on gradient organic heterojunction. However, the gradient heterojunction has yet been studied due to the complicated process and great random error inside. Especially in the field of transient optics, the light on/off in femto/picosecond range is vitally important for high-speed optical systems, such as application in fiber communications. In this paper, the wedge-structured organic heterojunction was fabricated based on molecular beam epitaxy. The devices were combined with both wedge-structured heterojunction and half-wave plate. When the probe light was tuned to 2.0 eV, a narrow passband was instantly observed once the pump and probe light were perpendicular to each other. The photoresponse can be achieved within 0.84 ps which can tune the optical signals on and off in transient optics. The results have demonstrated an exciting application in photo sensing.

Among the air pollutants, formaldehyde and particulate matter (PM) 2.5 are the most fatal pollutant sources of indoor pollution. Typically, electric motors have to be used for indoor vent air-clean systems, which are usually high energy consuming and high cost. Herein, we prepared a porous cellulose nanofiber (CNF) stringed HKUST-1 polyhedron membrane on stainless steel screen used as a window screen for air purification. The hierarchical porous structures of CNFs stringed HKUST-1 polyhedrons generate highly nanometer to micrometer pathways for fast air transportation but blocking PM2.5. The highly microporous cavities with open copper sites of HKUST-1 present efficient adsorption for formaldehyde. The corresponding blocking efficiency for PM2.5 is above 95% for a long time, and the adsorption capacity of formaldehyde is 47.71 mg g−1, which can dramatically low down the formaldehyde concentration to be less than 0.1 mg m−3 (the international safe standard of the indoor concentration of formaldehyde). Besides, due to the hierarchical but highly porous and thin thickness (∼5 μm), CNFs stringed HKUST-1 layer also demonstrates air flow rate of 4.6 cm s−1 under 200 Pa, which is enough for the indoor activity. This porous CNFs stringed HKUST-1 polyhedrons membrane on stainless steel screen has great potential for indoor air purification during haze weather.

The effect of variation of fruit orientation on online prediction of soluble solids content (SSC) of ‘Fuji’ apples based on visible and near-infrared (Vis/NIR) spectroscopy was studied. The diffuse reflectance spectra in 550–950 nm were collected with a designed online system in six orientations: stem-calyx axis vertical with stem upward (T1) and stem downward (T5), 45° between stem-calyx axis and horizontal with stem slope upward (T2) and stem slope downward (T4), stem-calyx axis horizontal with stem towards computer side lights (T3), stem-calyx axis horizontal with stem towards belt movement direction (T6). The 180 samples with SSC range of 8.00–13.60°Brix were divided into 135 of calibration set with 1.09 standard deviation (S.D.) and 45 of prediction set with 0.85 S.D. The signal-to-noise ratio (SNR) and area change rate (ACR) were used to evaluate the stability of collected spectra. After the comparison of different preprocessing methods, partial least squares (PLS) and least squares-support vector machine (LS-SVM) were used to develop compensation models of SSC for each orientation separately (local models) and all orientations (global model), respectively. Finally, competitive adaptive reweighted sampling (CARS), successive projection algorithm (SPA), and their combination were used to select the effective wavelengths (EWs), respectively. Results showed that T1 performed better for our system and influence of measurement orientation on spectra greatly affected SSC prediction accuracy. Comparatively, global model was insensitive to fruit orientation variation. 37 EWs selected by CARS-SPA-PLS model after Savitzky-Golay smoothing in all orientations achieved better results with rp and RMSEP of 0.815, 0.818, 0.837, 0.731, 0.807, 0.842 and 0.487, 0.484, 0.460, 0.573, 0.497, 0.453°Brix, respectively. Generally, global model with EWs could be promisingly used for online SSC prediction of apple.

Lodging is one of the main problems in maize production. Assessing the self-recovery ability of maize plants after lodging at different growth stages is of great significance for yield loss assessment and agricultural insurance claims. The objective of this study was to quantitatively analyse the effects of different growth stages and lodging severity on the self-recovery ability of maize plants using UAV-LiDAR data. The multi-temporal point cloud data obtained by the RIEGL VUX-1 laser scanner were used to construct the canopy height model of the lodging maize. Then the estimated canopy heights of the maize at different growth stages and lodging severity were obtained. The measured values were used to verify the accuracy of the canopy height estimation and to invert the corresponding lodging angle. After verifying the accuracy of the canopy height, the accuracy parameter of the tasselling stage was R2 = 0.9824, root mean square error (RMSE) = 0.0613 m, and nRMSE = 3.745%. That of the filling stage was R2 = 0.9470, RMSE = 0.1294 m, and nRMSE = 9.889%, which showed that the UAV-LiDAR could accurately estimate the height of the maize canopy. By comparing the yield, canopy height, and lodging angle of maize, it was found that the self-recovery ability of maize at the tasselling stage was stronger than that at the filling stage, but the yield reduction rate was 14.16~26.37% higher than that at the filling stage. The more serious the damage of the lodging is to the roots and support structure of the maize plant, the weaker is the self-recovery ability. Therefore, the self-recovery ability of the stem tilt was the strongest, while that of root lodging and root stem folding was the weakest. The results showed that the UAV-LiDAR could effectively assess the self-recovery ability of maize after lodging.

How plant competition varies with the changes of biotic and abiotic factors has been debated for a long time in the field of ecology. The aim of this study was to explore how neighbors and soil fertility influenced the intensity and importance of competition on species Stipa grandis and S. krylovii. We conducted a target species (S. grandis and S. krylovii) × soil fertility (low and high fertility) × competition treatment (4 treatments: two target species grown in monoculture and in mixture with each other, and in mixture with Leymus chinensis or Agropyron cristatum) microcosm experiment. We calculated the intensity (NIntA) and importance (NImpA) of neighbor-effect with additive symmetry for each target species under different treatments, and explored how the NIntA and NImpA were influenced by the target species, neighbor identity and soil fertility. We calculated the fertilizer-addition effect index on each target species to explore how neighbor identity influenced the index. (1) When target species in mixture with L. chinensis, both the NIntA and NImpA decreased with the increase of soil fertility. The NImpA was significantly negative on S. grandis under both soil fertility treatments and on S. krylovii under the high soil fertility treatment. (2) When target species in mixture with A. cristatum, the NIntA significantly influenced by the interaction between target species and soil fertility. The NImpA was significantly negative on S. grandis under the low soil fertility treatment and on S. krylovii under the high soil fertility treatment. (3) When in S. grandis – S. krylovii mixture system, the NIntA increased with the increase of soil fertility, and the NImpA showed no significant effects on each target species. (4) The fertilizer-addition effect was higher than zero for all treatments except the one on S. grandis in mixture with L. chinensis. The effect on S. krylovii was relatively lower than that on S. grandis in mixture with A. cristatum but was relatively higher in any of the other three competition treatments. The present findings demonstrated that the identities of both target and neighbor species influenced the fertilizer-addition effect and the responses of intensity and importance of competition to the changes of soil fertility. The present study showed the complexity of target species and neighbor identities in influencing the outcomes of plant competition, and provided novel insights into how plant competition driving the community dynamics in the context of soil fertility changes.

In the traditional method in the calculation of rock slope seepage, the amount of calculation is too large, and the calculation efficiency is too low. Therefore, the coupling analysis of seepage and deformation of slope based on symmetric finite element model is proposed. This paper analyzes the seepage characteristics and mechanism of the slope of geotechnical foundation pit, establishes the seepage field from two aspects of crack seepage and pore seepage, and analyzes the influence and action relationship between seepage field and slope stress field. Combined with the analysis results of the relationship between seepage field and stress field, the seepage stress coupling model of geotechnical foundation pit slope is established by using symmetrical finite element method, and the coupling calculation results of specific parameters are obtained under the model. In order to verify the effectiveness of the design method, comparative experiments are designed. The experimental results show that the seepage coefficient of surrounding rock in each area of the tunnel is different; compared with the traditional seepage deformation coupling calculation method, the time consumption of the designed slope seepage deformation coupling calculation method is shorter, which effectively improves the calculation efficiency of the geotechnical foundation pit slope seepage coupling.

Sprayer boom height (Hb) variations affect the deposition and distribution of droplets. An Hb control system is used to adjust Hb to maintain an optimum distance between the boom and the crop canopy, and an Hb detection sensor is a key component of the Hb control system. This study presents a new, low-cost light detection and ranging (LiDAR) sensor for Hb detection developed based on the principle of single-point ranging. To examine the detection performance of the LiDAR sensor, a step height detection experiment, a field ground detection experiment, and a wheat stubble (WS) height detection experiment as well as a comparison with an ultrasonic sensor were performed. The results showed that the LiDAR sensor could be used to detect Hb. When used to detect the WS height (HWS), the LiDAR sensor primarily detected the WS roots and the inside of the WS canopy. HWS and movement speed of the LiDAR sensor (VLiDAR) has a greater impact on the detection performance of the LiDAR sensor for the WS canopy than that for the WS roots. The detection error of the LiDAR sensor for the WS roots is less than 5.00%, and the detection error of the LiDAR sensor for the WS canopy is greater than 8.00%. The detection value from the LiDAR sensor to the WS root multiplied by 1.05 can be used as a reference basis for adjusting Hb, and after the WS canopy height is added to the basis, the value can be used as an index for adjusting Hb in WS field spraying. The results of this study will promote research on the boom height detection method and autonomous Hb control system.

This paper studies the migration and deposition of suspended particles in porous media. This problem results from the fact that during the operation of a groundwater source heat pump, the recharging process will contribute to the impairment of soil permeability. A coupling lattice Boltzmann method, discrete element method and immersed moving boundary method were used to investigate the migration of particles in porous media. The DKT (Drifting, Kissing, Tumbling) phenomena were employed to validate our program. The coupled effects of concentration, flow rate and pH on the clogging mechanism of the porous media were analyzed. Results show that, due to the repulsive barrier between the particles and porous media, there is a critical velocity. At a low flow rate, the deposition ratio increases with the increase in velocity. Beyond the critical velocity, the deposition ratio decreases when the velocity increases due to higher shear force. Permeability impairment increases with the increase in concentration, especially in the low flow rate condition. Changes in pH mainly affect the repulsive barrier. For a low flow rate, the decrease in repulsive barrier greatly promotes the deposition of particles. Under the condition of favorable deposition, the increase in flow rate reduces the deposition phenomenon. Under the condition of unfavorable deposition, the lower flow rate condition has a lower deposition ratio. The process of particle deposition and the dynamic motion after deposition were observed such as particles gliding over the surface. Accumulated particles in the downstream form bridges and hinder fluid flow. At a high flow rate, strong shear force is more capable of destroying bridges and recovering permeability. Adsorbed particles glide on the surface of the grain and deposit in the downstream. This paper aims to help understanding of the micro-events of particle deposition and the clogging process.

Monitoring and mapping forest carbon is critical for informing climate change mitigation measures. Evidence indicates that forest edges hold less carbon than the forest interior. In this study, usi...

In this paper, we have found that the efficiency of p-type mono-crystalline silicon (mono-Si) passivated emitter and rear contact (PERC) solar cells can be increased by $$0.12{\%}_{\mathrm {{abs.}}}$$ with the process of hydrogenation with electron injection (HEI). However, the same scheme was not suitable for p-type multi-crystalline silicon (mc-Si) solar cells. To promote power conversion efficiency (PCE) for the mc-Si solar cells, we have explored a developed HEI process for the mc-Si solar cells to improve the device performance. Meanwhile, we also analysed the mechanization inside the solar cells after applying the HEI process. Through the design of experiment (DOE), the correlation among injection current, temperature, injection time and efficiency improvement was analysed in detail. It was proved that mc-Si solar cells require higher current injection and temperature to passivate the complex impurities in the bulk, when compared to mono-Si solar cells. With the optimal scheme explored by this paper, the open circuit voltage ( $$U_{\mathrm {{oc}}}$$ ), short circuit current density ( $$J_{\mathrm {{sc}}}$$ ) and fill factor (FF) of p-type mc-Si solar cells, respectively, increased by 1.2 mV, 0.11 mA $$\hbox {cm}^{-\mathrm {{2}}}$$ and $$0.05{\%}_{\mathrm {{abs.}}}$$ , respectively. The efficiency was improved about $$0.11 \pm 0.005{\%}_{\mathrm {{abs.}}}$$ . These results will provide a certain method and basis for further improving the efficiency of mc-Si PERC cells and overcoming the light-elevated temperature-induced degradation by HEI process.

Phenylethanoid glycosides (PhGs) are compounds made of phenylethyl alcohol, caffeic acid and glycosyl moieties. The first published references about phenylethanoid glycosides concerned the isolation of echinacoside from Echinaceu ungustifolia (Asteraceae) in 1950 and verbascoside from Verbascum sinuatum (Scrophulariaceae) in 1963. Over the past 60 years, many compounds with these structural characteristics have been isolated from natural sources, and most of these compounds possess significant bioactivities, including antibacterial, antitumor, antiviral, anti-inflammatory, neuro-protective, antioxidant, hepatoprotective, and immunomodulatory activities, among others. In this review, we will summarize the phenylethanoid glycosides described in recent papers and list all the compounds that have been isolated over the past few decades. We will also attempt to present and assess recent studies about the separation, extraction, determination, and pharmacological activity of the excellent natural components, phenylethanoid glycosides.

Background Ubiquitously distributed benzene is a known hematotoxin. Increasing evidence has suggested that erythroid-related hematologic parameters may be sensitive to benzene exposure. Fat content, which is also closely associated with erythroid-related hematologic parameters, may affect the distribution and/or metabolism of benzene, and eventually benzene-induced toxicity. Methods To explore the influence of benzene exposure, fat content, and their interactions on erythroid-related hematologic parameters, we recruited 1669 petrochemical workers and measured their urinary S-phenylmercapturic acid (SPMA) concentration and erythroid-related hematological parameters. Indices for fat content included body fat percentage (BF%), plasma total cholesterol (TC) and triglycerides (TG), and occurrence of fatty liver. Results The dose-response curve revealed U-shaped nonlinear relationships of SPMA with hematocrit (HCT) and mean corpuscular hemoglobin concentration (MCHC) (P-overall P-nonlinear P-overall ≤0.005). We also observed modification effects of fat content on the associations between benzene exposure and erythroid-related hematological parameters, with workers of lower or higher BF% and TG more sensitive to benzene-induced elevation of MCHC (Pinteraction = 0.021) and benzene-induced decrease of HCT (Pinteraction = 0.050), respectively. We also found that some erythroid-related hematologic parameters differed between subgroups of workers with different SPMA levels and fat content combination. Conclusions Our study suggested that benzene exposure, fat content, and their interactions may affect erythroid-related hematological parameters in petrochemical workers in a complex manner that are worthy of further investigation.

In order to research thermal behavior of benzoyl peroxide(BPO) mixed with NaOH solution, dynamic and isothermal experiments were carried out by differential scanning calorimeter (DSC).Thermal safety software(TSS) was used to analysis thermal behavior. Two methods were established to obtain reaction thermodynamic parameters, model-free method(Friedman method) and model-based method. By Friedman method, the activation energy of BPO with NaOH solution changed greatly, which demonstrated that the reaction was a multi-step reaction. By model-based method, BPO with NaOH solution can be described as A→B→C, where the first step A→B is an autocatalytic reaction, the second step B→C is a n-order reaction. Finally, the self-accelerating decomposition temperature(SADT) was predicted and the result indicated that SADT of BPO with NaOH solution is -1℃, which is much lower than BPO.

In this paper, the effect of diffusion on pattern selection in a predator-prey model with Michaelis–Menten type predator nonlinear harvesting is investigated. From the analysis of stability and bifurcation, the stability of the positive equilibrium and the occurrence conditions for the Hopf bifurcation, as well as the Turing instability, are obtained. Consequently, different patterns will occur in the system. It is necessary and imperative to derive the amplitude equations for understanding pattern selection. To this end, the multiple time scale analysis technique is employed to obtain the amplitude equations at the critical value of the Turing instability. Further, by analyzing the amplitude equations, we could identify different patterns, such as spot-like, stripe-like, hexagon-like and mixed state patterns. Finally, numerical simulations show that the rationality of the theoretical analysis and the obtained results will enrich the dynamical investigation of the predator-prey model.

To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment (2013–2016) was conducted in southeastern China. The experiment was designed using six different rice––winter crop rotations: rice–fallow (RF), rice–wheat (RW), rice–potato with rice straw mulch (RP), rice–green manure (Chinese milk vetch; RC–G), rice–oilseed rape (RO), and rice–green manure crop (oilseed rape with fresh straw incorporated into soil at flowering; RO–G) and three N rates, N0 (0 kg N ha−1), N1 (142.5 kg N ha−1), and N2 (202.5 kg N ha−1). Average rice yields in the RF (5.93 t ha−1) rotation were significantly lower than those in the rotations with winter crops (7.20–7.48 t ha−1) under the N0 treatment, suggesting that incorporation of straw might be more effective for increasing soil N than winter fallow. The rice yield differences among the rotations varied by year with the N input. In general, the grain yields in the RP and RO–G rotations –were respectively 11.6–28.5% and 14.80–37.19% higher than those in the RF in plots with N applied. Increasing the N rate may have tended to minimize the average yield gap between the RF and the other rotations; the yield gaps were 18.55%, 4.14%, and 0.23% in N0, N1, and N2, respectively. However, the N recovery efficiency in the RF was significantly lower than that in other rotations, except for 2015 under both N1 and N2 rates, a finding that implies a large amount of chemical N loss. No significant differences in nitrogen agronomic efficiency (NAE) and physiological efficiency (NPE) were found between the rotations with legume (RC–G) and non–legume (RO and RW) winter crops, a result that may be due partly to straw incorporation. For this reason, we concluded that the return of straw could reduce differences in N use efficiency between rotations with and without legume crops. The degree of synchrony between the crop N demand and the N supply was evaluated by comparison of nitrogen balance degree (NBD) values. The NBD values in the RP and RW were significantly lower than those in the other rotations under both N1 and N2 rates. Thus, in view of the higher grain yield in the RP compared to the RW under the N1 rate, the RP rotation might be a promising practice with comparable grain yield and greater N use efficiency under reduced N input relative to the other rotations. The primary yield components of the RF and RP were identified as number of panicles m−2 and numbers of kernels panicle−1, respectively. The NAE and NPE were positively correlated with harvest index, possibly providing a useful indicator for evaluating N use efficiency. Keywords: Rice (Oryza sativa L.), Paddy–upland rotation, Nitrogen use efficiency, Winter crops

Gradient organic heterojunction has emerging as a new type of semiconductors with advantages of anisotropy photocurrent output, flexibility and low material cost. Although the gradient heterojunctions are attractive to the scientific community, bottlenecks such as the difficulty in fabrication has significantly limited its further development. In this work, we have investigated in-depth mechanisms of optical field distributions inside of the gradient heterojunction. Based on the simulation model, an anisotropy photocurrent ratio was predicted when the heterojunction was designed in wedge-shaped geometry. According to the simulations, it was found that the photocurrent ratio was linear change along with the ITO displacement, where the thickness combination of donor and acceptor was tuned in gradient. In order to prove the simulation, a gradient heterojunction was fabricated based on ultra-high vacuum molecular beam epitaxy. The experimental photocurrent ratio was in accordance with the simulation. The experimental result exhibited a possibility of fabricating gradient heterojunction based on epitaxy technique. In summary, we have exhibited a possibility of gradient heterojunction structure which has potential applications in position sensing.

Autocatalytic decompositions are common in fine chemistry. They are considered hazardous because they give rise to sudden heat evolution, often with unexpected initiation and unknown exogenous influences. The expression of autocatalytic factor Z cited from Benito-Perez model was firstly introduced. Through thermal safety software, simulations with different autocatalytic factors were carried out. The results demonstrated that the increase in autocatalytic factor resulted in the stronger autocatalytic decomposition. Furthermore, by the normalization of simulation curves, the relationship between autocatalytic strength and curve shape was found, i.e., higher degree of autocatalysis produced more meandering curve. The standard curves with different levels of autocatalytic factors were determined next. According to the standard curves area, five zones for different strengths of autocatalysis were divided, i.e., weak or no autocatalysis, less weak autocatalysis, moderate autocatalysis, less strong autocatalysis and strong autocatalysis. Finally, this classification approach was applied to two well-known substances, dicumyl peroxide and dimethyl sulfoxide; the rationality of this approach was verified by comparing classification results with previous studies. From this research, a new approach (normalization contrast method) is proposed to conveniently identify the autocatalytic strength for adiabatic instruments.

Cumene hydroperoxide (CHP) is prone to thermal decomposition in chemical industry, but there are few reports on the related phenomena in the reactor when decomposition occurs. In order to reveal the complex phenomena of fluid-solid coupled heat transfer, two-phase flow and multi-phase chemical reaction in the CHP decomposition, computational fluid dynamics (CFD) approach was applied to simulate the decomposition of CHP with different mass in a closed pressure vessel. Based on a known reaction scheme and the kinetics evaluated from differential scanning calorimeter (DSC) results, a comprehensive CFD model of CHP decomposition was created. As a result, detailed information on the reaction course was obtained, and distribution of temperature, pressure, reaction rate, and flow velocity in the vessel were also investigated. Finally, closed pressure vessel tests (CPVT) were conducted to verify the validity of the CFD model. This work is conducive to deeply understand the thermal decomposition and reactive hazards assessment of CHP.