反霸权新闻在新冠病毒溯源报道政治化过程中的作用

新冠病毒溯源是一个处于被政治化过程中的全球健康议题。本研究从反霸权新闻的视角出发,选取西方主流媒体:美国有线电视新闻网和非西方国际新闻传播机构:中国国际电视台、半岛电视台英文台、今日俄罗斯作为研究对象,以信源分析、框架分析等方法,分析4家媒体自新冠肺炎疫情暴发以来,其在病毒溯源相关报道的报道声量、报道信源和报道框架等方面的异同。研究发现,美国有线电视新闻网在选取报道信源时注意到了客观平衡,但较少使用“建设性—行政理性(合作)”框架,体现出较高超的报道操纵水平;中国国际电视台无论从报道信源还是报道框架上,都注重将病毒溯源引回科学轨道;半岛电视台英文台当议题与其主要资助方关联性较低的情况下,报道体现出更为客观、科学的特点;今日俄罗斯的报道则是4家新闻机构中最具政治色彩的。反霸权新闻在新冠病毒溯源报道中发出了不一样的声音,有助于抑制科学议题政治化倾向,增进国际舆论场关于特定议题报道的客观性与多元性。

Transcriptomic and genetic approaches reveal an essential role of the NAC transcription factor SlNAP1 in the growth and defense response of tomato

With global climate change,plants are frequently being exposed to various stresses,such as pathogen attack,drought,and extreme temperatures.Transcription factors(TFs)play crucial roles in numerous plant biological processes;however,the functions of many tomato(Solanum lycopersicum L.)TFs that regulate plant responses to multiple stresses are largely unknown.Here,using an RNA-seq approach,we identified SlNAP1,a NAC TF-encoding gene,which was strongly induced by various stresses.By generating SlNAP1 transgenic lines and evaluating their responses to biotic and abiotic stresses in tomato,we found that SlNAP1-overexpressing plants showed significantly enhanced defense against two widespread bacterial diseases,leaf speck disease,caused by Pseudomonas syringae pv.tomato(Pst)DC3000,and root-borne bacterial wilt disease,caused by Ralstonia solanacearum.In addition,SlNAP1 overexpression dramatically improved drought tolerance in tomato.Although the SlNAP1-overexpressing plants were shorter than the wild-type plants during the early vegetative stage,eventually,their fruit yield increased by 10.7%.Analysis of different hormone contents revealed a reduced level of physiologically active gibberellins(GAs)and an increased level of salicylic acid(SA)and abscisic acid(ABA)in the SlNAP1-overexpressing plants.Moreover,EMSAs and ChIP-qPCR assays showed that SlNAP1 directly activated the transcription of multiple genes involved in GA deactivation and both SA and ABA biosynthesis.Our findings reveal that SlNAP1 is a positive regulator of the tomato defense response against multiple stresses and thus may be a potential breeding target for improving crop yield and stress resistance.

Optimizing the electrolyte salt of aqueous zinc-ion batteries based on a high-performance calcium vanadate hydrate cathode material

It is urgent to develop high-performance cathode materials for the emerging aqueous zinc-ion batteries with a facile strategy and optimize the related components.Herein,a Ca0.23V2O5·0.95 H2O nanobelt cathode material with a rather large interlayer spacing of 13.0 A is prepared via a one-step hydrothermal approach.The battery with this cathode material and 3 M Zn(CF3SO3)2 electrolyte displays high specific capacity(355.2 mAh g^(-1) at 0.2 A g^(-1)),great rate capability(240.8 mAh g^(-1) at 5 A g^(-1)),and excellent cyclability(97.7% capacity retention over 2000 cycles).Such superior performances are ascribed to fast electrochemical kinetics,outstanding electrode/electrolyte interface stability,and nearly dendrite-free characteristic.Instead,when ZnSO4 or Zn(ClO4)2 is used to replace Zn(CF3SO3)2,the electrochemical performances become much inferior,due to the slow electrochemical kinetics,inhomogeneous Zn stripping/plating process,and the formation of large dendrites and byproducts.This work not only discloses a high-performance cathode material for aqueous zinc-ion batteries but also offers a reference for the choice of electrolyte salt.

Molten salt synthesis of α-MnO_(2)/Mn_(2)O_(3) nanocomposite as a high-performance cathode material for aqueous zinc-ion batteries

Thanks to low cost,high safety,and large energy density,aqueous zinc-ion batteries have attracted tremendous interest worldwide.However,it remains a challenge to develop high-performance cathode materials with an appropriate method that is easy to realize massive production.Herein,we use a molten salt method to synthesize nanostructured manganese oxides.The crystalline phases of the manganese oxides can be tuned by changing the amount of reduced graphene oxide added to the reactant mixture.It is found that the α-MnO_(2)/Mn_(2)O_(3) nanocomposite with the largest mass ratio of Mn_(2)O_(3) delivers the best electrochemical performances among all the products.And its rate capability and cyclability can be significantly improved by modifying the Zn anode with carbon black coating and nanocellulose binder.In this situation,the nanocomposite can deliver high discharging capacities of 322.1 and 213.6 mAh g^(-1) at 0.2 and 3 Ag^(-1),respectively.After 1000 cycles,it can retain 86.2% of the capacity at the 2 nd cycle.Thus,this nanocomposite holds great promise for practical applications.

Hyperbranched phthalocyanine enabling black-phase formamidinium perovskite solar cells processing and operating in humidity open air

The extreme instability of pureα-phase FAPbI_(3) under high humidity conditions restricts the highthroughput fabrication in unmodified air environments,resulting in poor performance ofα-phase FAPbI_(3) perovskite devices obtained by scalable fabrication methods.Here we synthesized hyperbranched copper phthalocyanine(HCuPc)as a supramolecular additive with twisted phthalocyanine units to realize the molecular-level encapsulation at the grain boundaries through supramolecular interaction,which greatly broadened the processing window of FAPbI_(3) under high humidity.At the same time,unlike traditional encapsulation layer that carrier can only be collected by tunneling effect,the twisted phthalocyanine ring of HCu Pc in perovskite films is more conducive to hole extraction.Finally,a record efficiency was achieved in pure FAPbI_(3) based inverted structured solar cell by blade-coating to the best of our knowledge,even under unmodified humid air conditions(relative humidity of 65%–85%).The best operational stability of 3D pure FAPbI_(3) devices can also be achieved at the same time and unencapsulated HCuPc-FAPbI_(3) device can even operate with negligible degradation for 100 h in the open air(RH 30%–40%).

Study on Separation of Factors of Production from Grain and Food Safety during the Evolution of Chinese Agricultural Structure

China is the world's largest food producer,and it also has the largest food demand. The stability of China's food production directly affects the supply and demand situation of the world food market. In the context of evolving Chinese agricultural structure,this paper studies the separation of factors of production from grain and issues concerning food safety. It is found that the arable land for food production within agricultural sector continues to flow to non-food production sector while the arable land is shrinking in China; the process of urbanization of population is the main reason for food production workforce reduction,resulting in a decline in the overall quality of the food production labor.By analyzing the panel data estimation results for food production function,it is found that arable land and labor are still important factors for food production in China at present,and their flow out of food production poses a major threat to food production and security.

The Impact of Quality of Labor on Farmers' Agricultural Production Benefits:A Case Study of Anyang City

In recent years,the Central Document No.1 has been all about the issues concerning agriculture,countryside and farmers,and especially the Central Document No.1 in 2013 highlighted the improvement of quality of the rural labor force to develop modern agriculture.The quality of labor is related to the improvement of production efficiency,and farmers' agricultural production benefits are related to the issues concerning agriculture,countryside and farmers,ultimately affecting the development process of modern agriculture.On the theoretical basis of human capital,this article carries out empirical analysis,calculates the farmers' agricultural production benefits,and analyzes the specific impact of quality of labor on farmers' agricultural production benefits.Finally,some recommendations are put forth to increase farmers' income.

Atomistic Surface Passivation of CH_(3)NH_(3)PbI_(3) Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors

Organic-inorganic halide perovskites(OIHPs)are recognized as the promising next-generation X-ray detection materials.However,the device performance is largely limited by the ion migration issue of OIHPs.Here,we reported a simple atomistic surface passivation strategy with methylammonium iodide(MAI)to remarkably increase the ion migration activation energy of CH_(3)NH_(3)PbI_(3)single crystals.The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects,while not introducing extra mobile ions,which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100Vmm^(-1).The X-ray detectors hence exhibit a record-high sensitivity above 700,000μC Gy^(-1)_(air) cm^(-2)under continuum X-ray irradiation with energy up to 50 keV,which enables an ultralow X-ray detection limit down to 1.5 nGy_(air)s^(-1).Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.

Stable and Highly Flexible Perovskite Solar Cells with Power Conversion Efficiency Approaching 20% by Elastic Grain Boundary Encapsulation

Here,we show that flexible perovskite solar cells(PSCs)with high operational stability and power conversion efficiency(PCE)approaching 20%were achieved by elastic grain boundary(GB)encapsulation.An introduction of trimethyltrivinylcyclotrisiloxane(V3D3)and solvent annealing(SA)resulted in an in situ cross-linking reaction between GBs and enlarged grain size that enabled oriented charge-transport properties to be achieved synchronously,leading to reduced sheet resistance with a high fill factor(FF)up to 82.93%in flexible PSCs.

兼容量产涂布过程的熔融共混结晶方法制备具有平衡相分离结构的高效有机太阳能电池

有机光伏器件中供体受体分子较差的混溶性和结晶不平衡已严重阻碍了其性能的进一步发展,这在兼容量产涂布的过程中尤为明显.本文提出了一种熔融共混结晶策略,在刮涂工艺中实现了分子尺度上有机太阳能电池异质结薄膜共混度与定向结晶度的提升,显著增加了给受体的接触面积并为激子解离与扩散提供高效通道.同时,供体受体间的平衡结晶同步实现了空穴与电子的有效传输和收集.该策略在多种体系中均实现了与传统方法制备器件相近的转换效率,如PM6/IT-4F器件的效率为13.86%(0.04 cm^(2))和11.48%(1 cm^(2));而PM6:BTP-BO-4F和PM6:Y6器件分别实现17.17%和16.14%的效率,显示其极具潜力的应用前景.

Detector-grade perovskite single-crystal wafers via stress-free gel-confined solution growth targeting high-resolution ionizing radiation

Solution-processed organic‒inorganic halide perovskite(OIHP)single crystals(SCs)have demonstrated great potential in ionizing radiation detection due to their outstanding charge transport properties and low-cost preparation.However,the energy resolution(ER)and stability of OIHP detectors still lag far behind those of melt-grown inorganic perovskite and commercial CdZnTe counterparts due to the absence of detector-grade high-quality OIHP SCs.Here,we reveal that the crystallinity and uniformity of OIHP SCs are drastically improved by relieving interfacial stress with a facial gel-confined solution growth strategy,thus enabling the direct preparation of large-area detector-grade SC wafers up to 4 cm with drastically suppressed electronic and ionic defects.The resultant radiation detectors show both a small dark current below 1 nA and excellent baseline stability of 4.0×10^(-8) nA cm^(-1) s^(-1) V^(-1),which are rarely realized in OIHP detectors.Consequently,a record high ER of 4.9% at 59.5 keV is achieved under a standard 241Am gamma-ray source with an ultralow operating bias of 5 V,representing the best gamma-ray spectroscopy performance among all solution-processed semiconductor radiation detectors ever reported.

Landing site positioning and descent trajectory reconstruction of Tianwen-1 on Mars

Tianwen-1(TW-1)is the first Chinese interplanetary mission to have accomplished orbiting,landing,and patrolling in a single exploration of Mars.After safe landing,it is essential to reconstruct the descent trajectory and determine the landing site of the lander.For this purpose,we processed descent images of the TW-1 optical obstacle-avoidance sensor(OOAS)and digital orthophoto map(DOM)of the landing area using our proposed hybrid-matching method,in which the landing process is divided into two parts.In the first,crater matching is used to obtain the geometric transformations between the OOAS images and DOM to calculate the position of the lander.In the second,feature matching is applied to compute the position of the lander.We calculated the landing site of TW-1 to be 109.9259◦E,25.0659◦N with a positional accuracy of 1.56 m and reconstructed the landing trajectory with a horizontal root mean squared error of 1.79 m.These results will facilitate the analyses of the obstacle-avoidance system and optimize the control strategy in the follow-up planetary-exploration missions.