农村产业发展应坚持“度、路、效”的有机统一

推动农村产业发展、实现农村产业兴旺是乡村振兴战略的重要内容和战略目标,为此,必须走中国特色农村产业发展之路,把握农村产业发展的精度深度与时度节度,坚持农村产业发展的有机融合,注重农村产业发展的综合效益。正确认识与把握农村产业发展的度、路、效对于实施乡村振兴战略具有重要的现实意义。

乡村振兴视阈下蒲江农村产业发展的度、路、效

推动农村产业发展、实现农村产业兴旺是乡村振兴战略的重要内容和战略目标,为此,必须走中国特色农村产业发展之路,把握蒲江农村产业发展的精度深度与时度节度,坚持蒲江农村产业发展的有机融合,注重蒲江农村产业发展的综合效益。正确认识与把握蒲江农村产业发展的度、路、效对于实施乡村振兴战略具有重要的现实意义。

乡村振兴视阈下农村产业发展的“度、路、效”

推动农村产业发展、实现农村产业兴旺是乡村振兴战略的重要内容和价值目标,为此,必须走中国特色农村产业发展之路,把握农村产业发展的精度深度与时度节度,坚持农村产业发展的有机融合,注重农村产业发展的综合效益。正确认识与把握农村产业发展的"度、路、效"对于实施乡村振兴战略具有重要的现实意义。

Path transition of the western boundary current with a gap due to mesoscale eddies: a 1.5-layer, wind-driven experiment

Using a 1.5 layer nonlinear shallow-water reduced-gravity model, we executed numerical simulations to investigate the possibility of a western boundary current (WBC) path transition due to mesoscale eddies based on the background of the Kuroshio intrusion into the South China Sea (SCS) from the Luzon Strait. Because the WBC existed different current states with respect to different wind stress control parameters, we chose three steady WBC states (loop current, eddy shedding and leaping) as the background flow field and simulated the path transition of the WBC due to mesoscale eddies. Our simulations indicated that either an anticyclonic or cyclonic eddy can lead to path transition of the WBC with different modes. The simulation results also show that the mesoscale eddies can lead to path transition of the WBC from loop and eddy shedding state to leaping state because of the hysteresis effect. The leaping state is relatively stable compared with the mesoscale eddies. Moreover, an anticyclonic eddy is more effective in producing the WBC path transition for the path transition than a cyclonic eddy. Our results may help to explain some phenomena observed regarding the path transition of the Kuroshio due to the mesoscale eddies at the Luzon Strait.

Design of Three-component Photoelastic Waveguide Accelerometer

In order to realize a high accuracy seismic exploration in the high electro-magnetic field and to improve oil producibility and recovery efficiency,a three-component photoelastic waveguide accelerometer is designed. Based on the photoelastic effect,the Mach-Zehnder integrated optical interferometer is designed to measure the three-orthogonal components of acceleration and the combined three-component simple harmonic vibrator is designed to reduce the cross-talk among the acceleration components. According to the variation of LiNbO3 waveguide phase under the action of the applied acceleration,the cross-axise sensitivity and transverse sensitivity ratio(TSR) were analysed. The results reveal that the accelerometer has wide band and good linearity. It can satisfy the sensor requirements of high accuracy seismic exploration. The main design parameters of the geophone system are:phase sensitivity:1.86×10-4 Rad·m-1·s-2,natural frequency:3 500 Hz,and the transverse sensitivity ratio:0.11%.

Effects of temperature variation on Li_xFe PO_4/C(0

Li Fe PO4/C was prepared via solid state reaction and characterized with X-ray powder diffraction and charge–discharge test. As-prepared Li Fe PO4/C has a triphylite structure and exhibits an excellent rate capability and capacity retention. Electrochemical impedance spectroscopy(EIS) was applied to investigate LixFe PO4/C(0<x<1) electrode on temperature variation. The valid equivalent circuit for EIS fitting was determined which contains an intercalation capacitance for Li+ ion accumulation and consumption in the electrode reaction. The surface layer impedance needs to be included in the equivalent circuit when Li Fe PO4/C is deeply delithiated at a relatively high temperature. EIS examination indicates that a temperature rise leads to a better reversibility, lower charge transfer resistance, higher exchange current density J0 and greater Li+ ion diffusion coefficient for the LixFe PO4/C electrode process. The Li+ ion concentration in LixFe PO4/C is potential to impact the Li+ ion diffusion coefficient, and a decrease in the former results in an increase in the latter.

Investigation on interaction and characteristics of traffic flows in urban elevated road-ramp-ground road system

The rapid development of the automobile industry and the relative lag of the road construction have constituted a prominent contradiction all over the world, particularly, in most of large cities. To cope with it, elevated roads have been built in many cities both at home and abroad. However, traffic jams frequently appear on elevated roads immediately after the completion of their construction. The awkward situation mainly results from the planning bug or the unsuitable control, apart from drastic increase in transportation demand. Elevated roads,

Effect of geogrid reinforcement on soft and medium dense soils

The field tests were carried out to examine the reinforcement effect of a geogrid on various conditions of embankment height,the number of passages of vibratory roller,the number of reinforced layer of geogrid,and soil properties.The test results of the dynamic earth pressure indicate that the soil reinforced by geogrid is very effective to increase the stiffness of soil,especially in soft soil.The dynamic earth pressure ratio,which is defined as the ratio of dynamic earth pressure to self weight of soils,exponentially decreases as the embankment height increases.The dynamic earth pressure ratio increases up to 80% for soft soils reinforced by both one layer of geogrid in place of no reinforced soils and two layers in place of a single layer of geogrid.

Frame Aggregation Scheme Based on Dynamic Pricing

Frame aggregation is a wireless link optimization mechanism that aims to reduce transmission overheads by sending multiple flames as the payload of a single MAC flame. It is considered as one of the most efficient methods to improve the wireless channel utilization and the throughput of wireless networks. The static assignment of frame aggregation parameters can result in delay penalties due to variations in traffic type. We propose a frame aggregation scheme which is based on dyn- amic pricing and queue scheduling for a multi- traffic scenario. The scheme adopts a dynamic differential pricing scheme for different types of traffic. Meanwhile, it polls buffer queues in accordance with the optimal aggregation wei- ght factors to maximise the network revenue. Simulation results indicate that the proposed frame aggregation scheme can effectively improve the network revenue and the average throughput, while guaranteeing the delay requirements of all types of traffic.

Vacuum degree effects on betavoltaics irradiated by ^(63)Ni with differently apparent activity densities

For many current betavoltaics, beta sources and PN junction energy conversion units are separated. The air gap between the two parts could stop part of decay beta particles, which results in inefficient performance of the betavoltaic. By employing 63Ni with an apparent emission activity density of 7.26×10~7 and 1.81×10~8 Bq cm^(-2), betavoltaic performance levels were calculated at a vacuum degree range of 1×10~5 to 1×10^(-1) Pa and measured at 1.0×10~5 and 1.0×10~4 Pa, respectively. Results show that betavoltaic performance levels improve significantly as the vacuum degree increases. The maximum output power (P_(max)) exhibits the largest change, followed by short-circuit current (I_(sc)), open-circuit voltage (V_(oc)), and fill factor. The vacuum degree effects on Isc, Voc,and Pmax of the betavoltaic with low apparent activity density 63Ni are more significant than those of the betavoltaic with high apparent activity density ^(63)Ni. Moreover, the improved efficiencies of the measured performances are larger than the calculated efficiencies because of the low ratio of Isc and reverse saturation current (I_0). The values of I0, ideality factor, and shunt resistance were estimated to modify the equivalent circuit model. The calculation results based on this model are closer to the measurement results. The results of this research can provide a theoretical foundation and experimental reference for the study of vacuum degree effects on betavoltaics of the same kind.

Optimization and degradation of rubrene/C_(70) heterojunction solar cells

Small molecule organic solar cells （OSCs） with the structure of indium tin oxide （1TO）/molybdenum trioxide （MOO3） （5 nm）/rubrene （x nm）/fullerene （C70） （y nm）/2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline （BCP） （6 nm）/aluminum （A1） （150 nm） are fabricated. The thickness of active layer for the devices is investigated in details. The results show that the optimum thicknesses of rubrene layer and C70 layer are 30 nm and 25 nm, respectively. The degradation of the device is also investigated. The result indicates that the open-circuit voltage （Voo） does not change, while the short-circuit current density （Jsc）, fill factor （FF） and power conversion efficiency （PCE） decrease continuously with time. The degradation can be attributed to the oxygen in ambient diffusing and infiltrating into the active materials and reacting with C70 in cells, which can result in the increase of interfacial series resistance.

Formation of efficient dye-sensitized solar cells by introducing an interfacial layer of hierarchically ordered macro-mesoporous TiO_2 film

Hierarchically ordered macro-mesoporous TiO2 films (Ti-Ma-Me) were fabricated on fluorine-doped tin oxide (FTO) substrates through the confinement self-assembly method. The prepared Ti-Ma-Me possesses periodically ordered structure and a large specific surface area, which was applied as an interfacial layer between the nanocrystalline TiO2 film (P25-TiO2) and FTO electrode in the dye-sensitized solar cell (DSSC). The introduction of a Ti-Ma-Me interfacial layer increased the shortcircuit current density (Jsc) from 7.49 to 10.65 mA/cm2 and the open-circuit voltage (Voc) from 0.65 to 0.70 V as the result of its improved light harvesting efficiency by allowing for the high roughness factor and enhanced multiple internal reflection or scattering as well as reducing the back-transport reaction by blocking direct contact between the electrolyte and FTO electrode. Therefore, the photovoltaic conversion efficiency (η) was improved by 83% from 3.04% to 5.55%, as compared to a device using a bare P25 TiO2 photoanode.

A low-temperature TiO2/SnO2 electron transport layer for high-performance planar perovskite solar cells

Conventional titanium oxide(TiO2) as an electron transport layer(ETL) in hybrid organic-inorganic perovskite solar cells(PSCs) requires a sintering process at a high temperature to crystalize, which is not suitable for flexible PSCs and tandem solar cells with their low-temperatureprocessed bottom cell. Here, we introduce a low-temperature solution method to deposit a TiO2/tin oxide(SnO2) bilayer towards an efficient ETL. From the systematic measurements of optical and electronic properties, we demonstrate that the TiO2/SnO2 ETL has an enhanced charge extraction ability and a suppressed carrier recombination at the ETL/perovskite interface, both of which are beneficial to photo-generated carrier separation and transport. As a result, PSCs with TiO2/SnO2 bilayer ETLs present higher photovoltaic performance of the baseline cells compared with their TiO2 and SnO2 single-layer ETL counterparts. The champion PSC has a power conversion efficiency(PCE) of 19.11% with an open-circuit voltage(Voc)of 1.15 V, a short-circuit current density(Jsc) of 22.77 mA cm^-2,and a fill factor(FF) of 72.38%. Additionally, due to the suitable band alignment of the TiO2/SnO2 ETL in the device, a high Vocof 1.18 V is achieved. It has been proven that the TiO2/SnO2 bilayer is a promising alternative ETL for high efficiency PSCs.

Fullerenes and derivatives as electron transport materials in perovskite solar cells

In this study,two fullerenes(C60,C70)and their methano-substitutions(PC61BM,PC71BM),as electron transport materials(ETMs)in perovskite solar cells(Pero-SCs),were systematically studied.As being used as ETMs,methanofullerenes,though with lower electron mobility compared to the counterpart pristine fullerenes,lead to higher power conversion efficiencies(PCEs)of Pero-SCs.The difference is likely caused by the fill-out vacancies and smoother morphology of the interfaces between ETM and perovskite layers,as they were prepared by different methods.In addition,compared to C60 and PC61BM,C70 and PC71BM showed priority in terms of short-circuit current density,which should be attributed to fast free charge extraction abilities.

Al-doping effects on the photovoltaic performance of inverted polymer solar cells

The properties of Al-doped Zn O(AZO) play an important role in the photovoltaic performance of inverted polymer solar cells(PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor(FF) simultaneously, and the power conversion efficiency(PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.

Lock-up function of fluorine enhances photovoltaic performance of polythiophene

Three model polythiophenes,PTCBT,PTCFBT and PFTCBT,have been synthesized to investigate the effect of fluorination on photovoltaic performance of polythiothenes.Compared with PTCBT,PFTCBT with F atom on TC unit shows a narrower optical bandgap(1.79 eV),higher crystallinity,and ideal morphology in the active layer,leading to a higher short-circuit current density(J_(SC))of 11.84 mA/cm^2 and a power conversion efficiency(PCE)of 5.93%.The lock-up function of fluorine enhances polythiophene backbone planarity and molecular packing.

A-D-A small molecule donors based on pyrene and diketopyrrolopyrrole for organic solar cells

Three new electron donating small molecules （SMs）, Pyr（EH-DPP）2, Pyr（HD-DPP）2 and PyrA（EH-DPP）2, are designed and synthesized through coupling electron rich pyrene core with electron deficient diketopyrrolopyrrole （DPP） terminals, of which the derived organic solar cells （OSCs） exhibit interesting structure-performance correlation. It shows that the tune of their solubilizing side chains and n-bridge for the acceptor-donor-acceptor （A-D-A） SMs can significantly alter the resultant short-circuit current density and power conversion efficiency （PCE） in OSCs. The Pyr（EH-DPP）2 with short side chains displays broader absorption and higher hole mobility than the Pyr（HD-DPP）2 with long side chains. Although showing planar structure, the acetylene bridge-incorporated PyrA（EH-DPP）2 adapts an undesired edge-on packing and strong aggregation in film, leading to non-ideal morphology and poor miscibility with fullerene acceptors. As a result, the PCE of the solar cell based on Pyr（EH-DPP）2 is several times higher than those based on Pyr（HD-DPP）： and PyrA（EH-DPP）2, indicating the A-D-A combination of polyaromatics with DPP would be the promising skeleton for developing photovoltaic semiconductors.