High Areal Capacity and Long Cycle Life Flexible Mild Quasi-Solid-State Ag-Zn Battery with Dendrite-Free Anode

Silver-zinc(Ag-Zn)batteries are a promising battery system for flexible electronics owing to their high safety,high energy density,and stable output voltage.However,poor cycling performance,low areal capacity,and inferior flexibility limit the practical application of Ag-Zn batteries.Herein,we develop a flexible quasi-solid-state Ag-Zn battery system with superior performance by using mild electrolyte and binder-free electrodes.Copper foam current collector is introduced to impede the growth of Zn dendrite,and the structure of Ag cathode is engineered by electrodeposition and chloridization process to improve the areal capacity.This novel battery demonstrates a remarkable cycle retention of 90%for 200 cycles at 3 mA cm^(-2).More importantly,this binder-free battery can afford a high capacity of 3.5 mAh cm^(-2)at 3 mA cm^(-2),an outstanding power density of 2.42 mW cm^(-2),and a maximum energy density of 3.4 mWh cm^(-2).An energy management circuit is adopted to boost the output voltage of a single battery,which can power electronic ink display and Bluetooth temperature and humidity sensor.The developed battery can even operate under the extreme conditions,such as being bent and sealed in solid ice.This work offers a path for designing electrodes and electrolyte toward high-performance flexible Ag-Zn batteries.

Molybdenum and tungsten chalcogenides for lithium/sodium-ion batteries: Beyond MoS2

Molybdenum and tungsten chalcogenides have attracted tremendous attention in energy storage and conversion due to their outstanding physicochemical and electrochemical properties.There are intensive studies on molybdenum and tungsten chalcogenides for energy storage and conversion,however,there is no systematic review on the applications of WS2,Mo Se2and WSe2as anode materials for lithium-ion batteries(LIBs)and sodium-ion batteries(SIBs),except Mo S2.Considering the importance of these contents,it is extremely necessary to overview the recent development of novel layered WS2,Mo Se2and WSe2beyond Mo S2in energy storage.Here,we will systematically overview the recent progress of WS2,Mo Se2and WSe2as anode materials in LIBs and SIBs.This review will also discuss the opportunities,and perspectives of these materials in the energy storage fields.

Porous bowl-shaped VS2 nanosheets/graphene composite for high-rate lithium-ion storage

Two-dimensional (2D) layered vanadium disulfide (VS2) is a promising anode material for lithium ion batteries (LIBs) due to the high theoretical capacity.However,it remains a challenge to synthesize monodispersed ultrathin VS2 nanosheets to realize the full potential.Herein,a novel solvothermal method has been developed to prepare the monodispersed bowl-shaped NH3-inserted VS2 nanosheets (VS2).The formation of such a unique structure is caused by the blocked growth of (001) or (002) crystal planes in combination with a ripening process driven by the thermodynamics.The annealing treatment in Ar/H2creates porous monodispersed VS2(H-VS2),which is subsequently integrated with graphene oxide to form porous monodispersed H-VS2/rGO composite coupled with a reduction process.As an anode material for LIBs,H-VS2/rGO delivers superior rate performance and longer cycle stability:a high average capacity of 868/525 mAh g^-1 at a current density of 1/10 A g^-1;a reversible capacity of 1177/889 mAh g^-1 after 150/500 cycles at 0.2/1 A g^-1.Such excellent electrochemical performance may be attributed to the increased active sites available for lithium storage,the alleviated volume variations and the shortened Li-ion diffusion induced from the porous structure with large specific surface area,as well as the protective effect from graphene nanosheets.

Electrospun CoSe@N-doped carbon nanofibers with highly capacitive Li storage

One-dimensional nano-structured materials have attracted attention due to its unique properties afforded such as the across-linked structures and large aspect ratios.In this work,one-dimensional CoSe@N-doped carbon nanofibers(CoSe@NCNFs)are successfully by combining the techniques of electrospinning and annealing.Selenium powder are directly dispersed in the polyacrylonitrile/N,N-Dimethylformamide(DMF)solution containing cobalt salt to form the product.The performance of these materials was investigated in Li-ion batteries after the annealing at different temperatures.The Co Se@NC nanofibers annealed at 550℃(CoSe@NC-550)and displayed excellent storage properties,affording a high capacity of 796 m Ah·g-1at a current density of 1 A·g^-1 for 100 cycles.Moreover,it is confirmed that the pseudocapacitive contribution of CoSe@NC-550 is up to 72.8%at the scan rate of 1 mV/s through the cyclic voltammetry analysis.

Temporal-spatial subspaces modern combination method for 2D-DOA estimation in MIMO radar

A 2D-direction of arrival estimation (DOAE) for multi input and multi-output (MIMO) radar using improved multiple temporal-spatial subspaces in estimating signal parameters via rotational invariance techniques method (TS-ESPRIT) is introduced. In order to realize the improved TS-ESPRIT, the proposed algorithm divides the planar array into multiple uniform sub-planar arrays with common reference point to get a unified phase shifts measurement point for all sub-arrays. The TS-ESPRIT is applied to each sub-array separately, and in the same time with the others to realize the parallelly temporal and spatial processing, so that it reduces the non-linearity effect of model and decreases the computational time. Then, the time difference of arrival (TDOA) technique is applied to combine the multiple sub-arrays in order to form the improved TS-ESPRIT. It is found that the proposed method achieves high accuracy at a low signal to noise ratio (SNR) with low computational complexity, leading to enhancement of the estimators performance.

CPTA treatment reveals potential transcription factors associated with carotenoid metabolism in flowers of Osmanthus fragrans

Osmanthus fragrans is one of the top ten traditional flowers in China.It is divided into three different groups according to its color.α-Carotene and β-carotene are the main determinants to distinguish the color differences between three groups.However,the dominant genes and transcription factors involved in carotenoid metabolism remain unclear.CPTA treatment(0.7mmol·L−1)remarkably promoted lycopene,α-carotene and β-carotene contents in flowers.Transcriptome sequencing analysis revealed that CPTA treatment could trigger chain reactions in carotenoid metabolism pathway genes.Four up-regulated and 10 down-regulated transcription factors which have close association with carotenoid variation were significantly induced by CPTA treatment.The up-regulated TFs such as MYB43,MYB123,HSF,were further subjected to transcript expression determination in different cultivars with drastic colors.Among them,transcript expression of four up-regulated TFs coincided with the carotenoid accumulation in different cultivars.We selected up-regulated OfMYB43 to verify its function,which is related to stress tolerance and transcriptional regulation.Transient overexpression of OfMYB43 in O.fragrans flowers showed that it could remarkably promote the expression of PDS,ZISO,LCYE and CCD4,leading to increased accumulation of β-branch carotenoids.OfMYB43 was a potential positive regulator of carotenoid biosynthesis in O.fragrans flowers.This study provides insight into the molecular mechanism of carotenoid metabolism in O.fragrans.

Whole-genome resequencing of Osmanthus fragrans provides insights into flower color evolution

Osmanthus fragrans is a well-known ornamental plant that has been domesticated in China for 2500 years.More than 160 cultivars have been found during this long period of domestication,and they have subsequently been divided into four cultivar groups,including the Yingui,Jingui,Dangui,and Sijigui groups.These groups provide a set of materials to study genetic evolution and variability.Here,we constructed a reference genome of O.fragrans‘Liuyejingui’in the Jingui group and investigated its floral color traits and domestication history by resequencing a total of 122 samples,including 119 O.fragrans accessions and three other Osmanthus species,at an average sequencing depth of 15×.The population structure analysis showed that these 119 accessions formed an apparent regional cluster.The results of linkage disequilibrium(LD)decay analysis suggested that varieties with orange/red flower color in the Dangui group had undergone more artificial directional selection;these varieties had the highest LD values among the four groups,followed by the Sijigui,Jingui,and Yingui groups.Through a genome-wide association study,we further identified significant quantitative trait loci and genomic regions containing several genes,such as ethylene-responsive transcription factor 2 and Arabidopsis pseudoresponse regulator 2,that are positively associated with petal color.Moreover,we found a frameshift mutation with a 34-bp deletion in the first coding region of the carotenoid cleavage dioxygenase 4 gene.This frameshift mutation existed in at least one site on both alleles in all varieties of the Dangui group.The results from this study shed light on the genetic basis of domestication in woody plants,such as O.fragrans.

Electrochemical CO2 reduction over nitrogen-doped SnO2 crystal surfaces

Crystal planes of a catalyst play crucial role in determining the electrocatalytic performance for CO2 reduction.The catalyst SnO2 can convert CO2 molecules into valuable formic acid(HCOOH).Incorporating heteroatom N into SnO2 further improves its catalytic activity.To understand the mechanism and realize a highly efficient CO2-to-HCOOH conversion,we used density functional theory(DFT)to calculate the free energy of CO2 reduction reactions(CO2RR)on different crystal planes of N-doped SnO2(N-SnO2).The results indicate that N-SnO2 lowered the activation energy of intermediates leading to a better catalytic performance than pure SnO2.We also discovered that the N-Sn O2 (211)plane possesses the most suitable free energy during the reduction process,exhibiting the best catalytic ability for the CO2-to-HCOOH conversion.The intermediate of CO2RR on N-SnO2 is HCOO*or COOH* instead of OCHO*.These results may provide useful insights into the mechanism of CO2RR,and promote the development of heteroatomdoped catalyst for efficient CO2RR.

Flexible quasi-solid-state dual-ion asymmetric supercapacitor based on Ni（OH）2 and Nb2O5 nanosheet arrays

Increasing the energy density, power density as well as widening the operation voltage are essential to electrochemical capacitors to meet the practical energy demands. Herein, a novel flexible quasi-solid-state dual-ion asymmetric supercapacitor(ASC) with Ni(OH)2 and Nb2O5 nanosheets directly grown on stainless steel mesh is developed. In the dual-ion ASC, Nb2O5 negative and Ni(OH)2 positive electrodes react with Li+ and OH- respectively in alkaline gel electrolyte to store energy, which is quite different from conventional alkali metal ion SCs and alkaline SCs. The as-assembled flexible device has an extended working voltage of 1.7 V and delivers a capacity of 5.37 mAh cm-2, a maximum energy density and power density of 0.52 mWh cm-3 and 170 mW cm-3 , respectively. The device maintains around 60% capacity retention after long cycling up to 1000 cycles. Moreover, our device can light up a LED light efficiently upon fast charging. The proposed quasi-solid-state dual-ion ASC has potential applications in future portable electronics and flexible energy storage devices.

Reversible Magnesium Metal Anode Enabled by Cooperative Solvation/Surface Engineering in Carbonate Electrolytes

Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping,while they fail to match most cathode materials toward highvoltage magnesium batteries. Herein,reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl_(2) additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg^(2+) desolvation barrier for accelerated redox kinetics,while the Mg^(2+)-conducting polymer coating on the Mg surface ensures the facile Mg^(2+) migration and the e ective isolation of electrolytes. As a result,reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover,benefitting from the wide electrochemical window of carbonate electrolytes,high-voltage(> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries.

Recent progress in 2D materials for flexible supercapacitors

High performance supercapacitors coupled with mechanical flexibility are needed to drive flexible and wearable electronics that have anesthetic appeal and multi-functionality. Two dimensional（2D） materials have attracted attention owing to their unique physicochemical and electrochemical properties, in addition to their ability to form hetero-structures with other nanomaterials further improving mechanical and electrochemical properties. After a brief introduction of supercapacitors and 2D materials, recent progress on flexible supercapacitors using 2D materials is reviewed. Here we provide insights into the structure–property relationships of flexible electrodes, in particular free-standing films. We also present our perspectives on the development of flexible supercapacitors.

Satellite dataset analysis of recent vegetation variation in Tibet region

This research investigates the recent distribution variation trends of vegetation in the Tibet region using Normalized Difference Vegetation Index （NDVI） data from 2000 to 2007. It also discusses the causes of vegetation degradation in typical regions （such as Nagqu） based on climatic conditions, human activity, and other influencing factors. Results show that the areas with the best vegetation cover are in Nyingchi and the southern part of Shannan, followed by Chamdo, the Lhasa area, and the eastern part of Nagqu. Vegetation in various regions exhibits significant seasonal differences. The vegetation status has improved in some parts of the Tibet region in the past few years, while the areas with the most serious degradation are in the middle and southem parts of the Nagqu region. On average, distinct vegetation degradation occurred between 2003 and 2006 in the whole Tibet region but vegetation has been increasing since 2006. The vegetation cover in summer basically determines the annual vegetation status. An increase in precipitation and decrease in wind speed generally corresponds to an increase in vegetation cover. The reverse is also true： a decrease in precipitation and increase in wind speed correspond to the decrease in vegetation cover. NDVI is thus positively related to temperature and precipitation but has a negative relation with wind speed. Increasing temperature and decreasing precipitation have led to the present vegetation degradation in Nagqu, and vegetation in all of these regions has been affected by growth of human population, intensified urbanization, livestock overgrazing leading to the proliferation of noxious plants, extraction of underground minerals and alluvial gold, extensive harvesting of traditional Chinese medicinal plants [e.g., Cordyceps sinensis, Caladium spp., and saffron crocus （Crocus sativus）], and serious rodent and other pest damage.

Alkyl group functionalization-induced phonon thermal conductivity attenuation in graphene nanoribbons

We calculated the room-temperature phonon thermal conductivity and phonon spectrum of alkyl group-functionalized zigzag graphene nanoribbons(ZGNRs) with molecular dynamics simulations. The increase in both chain length and concentration of alkyl groups caused remarkable reduction of phonon thermal conductivity in functionalized ZGNRs. Phonon spectra analysis showed that functionalization of ZGNR with alkyl functional groups induced phonon–structural defect scattering, thus leading to the reduction of phonon thermal conductivity of ZGNR. Our study showed that surface functionalization is an effective routine to tune the phonon thermal conductivity of GNRs, which is useful in graphene thermal-related applications.

The effects of fall fertilization on the growth of Chinese pine and Prince Rupprecht’s larch seedlings

Nutrient loading in the fall is a practical way to improve seedling quality and has been proven to increase nutrient accumulation,translocation and utilization.Few studies have reported on the variation in free amino acids as a result of fall fertilization,especially for diff erent seasonal needle habits(evergreen,deciduous).Therefore,a balanced two-factor factorial design with one fall fertilization treatment(10 mg N/seedling)and Chinese pine(Pinus tabulaeformis Carr.)and Prince Rupprecht’s larch(Larix principis-rupprechtii Mayr.)seedlings was used to examine growth response over one nursery season.Associated changes between fall fertilization,N storage and free amino acids were analyzed.Results showed that:(1)stem height,diameter and biomass for both species were similar between controls and fall fertilization treatments;(2)compared to controls,fall fertilization increased Chinese pine needle and root N by 17.7%and 36.9%,respectively.For Prince Rupprecht’s larch,fall fertilization resulted in 26.3%and 34.54%more N in stem and roots,respectively,than controls;(3)the three main amino acids in control and fertilization treatments in Prince Rupprecht’s larch seedlings were glutamine,arginine and proline,and in Chinese pine seedlings were glutamine,arginine andγ-amino butyric acid;(4)total amino acid contents were not signifi cantly increased by fall fertilization,but glutamine in Chinese pine and Prince Rupprecht’s larch increased by 64.2%and 35.2%,respectively.Aboveground biomass of Prince Rupprecht’s larch had higher proline contents than Chinese pine,which suggests that the stress resistance of the aboveground tissue may be higher for Prince Rupprecht’s larch.The results indicate that diff erent plant organs with various response are well adapted to nitrogen loading for nutrient storage in evergreen and deciduous conifer seedlings.

Functional butter for reduction of consumption risk and improvement of nutrition

Butter has become renowned among consumers because of its exceptional flavor and taste.Nevertheless,conventional butter is deemed“unhealthy”due to its high concentration of saturated fats and cholesterol,which are linked to the development of cardiovascular ailments.Improving the health benefits of butter has become an essential topic of research in the butter industry.This review focuses on researches that have made improvements to functionality of butter,including the changes in fatty acid composition,cholesterol reduction,incorporation with bioactive substances,development of new sources.The reduction of saturated fatty acids and cholesterol in butter can help reduce the risk of disease from eating butter.In addition,incorporating probiotics or natural plant extracts can achieve nutritional functions such as balancing intestinal flora,enhancing nutrient absorption,and increasing the body’s antioxidant capacity.Butter substitute products can be based on new vegetable oils,insect fats or microbial fats,which cater to the consumer demands for low-calorie butter while reducing the environmental impact that results from butter production.This review summarizes the effects and characteristics of various improvement methods and proposes some possible directions for future development of functional butter.

MTBSTFA derivatization-LC-MS/MS approach for the quantitative analysis of endogenous nucleotides in human colorectal carcinoma cells

Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85%methanol followed by a simple derivatization reaction within 5 min at room temperature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical C;column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4μM for the tested RNs and 0.001-0.1μM for dRNs.In addition,the precision(CV)was<15%and the RSD of stability was lower than 10.4%.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT 116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.

The telomere-to-telomere gap-free reference genome of wild blueberry (Vaccinium duclouxii) provides its high soluble sugar and anthocyanin accumulation

Vaccinium duclouxii,endemic to southwestern China,is a berry-producing shrub or small tree belonging to the Ericaceae family,with high nutritive,medicinal,and ornamental value,abundant germplasm resources,and good edible properties.In addition,V.duclouxii exhibits strong tolerance to adverse environmental conditions,making it a promising candidate for research and offering wide-ranging possibilities for utilization.However,the lack of V.duclouxii genome sequence has hampered its development and utilization.Here,a high-quality telomere-to-telomere genome sequence of V.duclouxii was de novo assembled and annotated.All of 12 chromosomes were assembled into gap-free single contigs,providing the highest integrity and quality assembly reported so far for blueberry.The V.duclouxii genome is 573.67 Mb,which encodes 41953 protein-coding genes.Combining transcriptomics and metabolomics analyses,we have uncovered the molecular mechanisms involved in sugar and acid accumulation and anthocyanin biosynthesis in V.duclouxii.This provides essentialmolecular information for further research on the quality of V.duclouxii.Moreover,the high-quality telomere-to-telomere assembly of the V.duclouxii genome will provide insights into the genomic evolution of Vaccinium and support advancements in blueberry genetics and molecular breeding.

Research aiming at the significance of carrying out intercultural education in process of English teaching

Culture is one of the important properties of language, and language can not be separated from society and culture. Every language is the reflection of culture with profound cultural connotations. Many experts and scholars have generally agreed that intercultural communication competence is an important purpose of language learning. The process of learning English is the process to understand and master English cultural and knowledge, and mastery degree of English-speaking countries and cultural knowledge directly affects practical skills of one person.

3D-printed hierarchical porous and multidimensional conductive network based on conducting polymer/graphene oxide

Designing ultrathick and hierarchical electrodes is effective to deal with the challenge of high areal capacity and high power density for lithium-ion batteries(LIBs)manufacturing.Here,a thick electrode with hierarchical porous and multidimensional conductive network is fabricated by 3D printing tech-nology,in which both the conducting polymer of poly(3,4-ethylene dioxythiophene):polystyrene sul-fonate(PEDOT:PSS)and graphene oxide(GO)play the dual roles as binders and conductive agents.As a consequence,the 3D-printed thick electrode(~900 mm)with a mass loading of~47 mg/cm^(2) exhibits a good rate capability of 122 mA·h/g at 2 C,a high areal capacity of up to 5.8 mA·h/cm^(2),and stable cycling performance of~95%capacity retention after 100 cycles.Moreover,the C-O-S bond is further confirmed by the spectral analysis and the DFT calculation,which not only hinders the stack of nanosheets but enhances the mechanical stability and electronic conductivity of electrodes.A stable covalent multidi-mensional conductive network constructed by 3D-printing technology provides a new design strategy to improve the performance of LIBs.

中国健康体检人群脊柱定量CT骨密度与血红蛋白及白蛋白的相关性

目的采用定量CT技术测量中国健康体检人群脊柱骨密度, 探讨其与血红蛋白及人血白蛋白的相关性。方法本研究数据来自中国健康定量CT大数据项目数据(China Biobank), 脊柱骨密度测量采用 QCT Pro图像分析系统, 所有合作中心均采用欧洲脊柱体模(NO.145)进行质量控制。选取符合入组标准的50 053例健康体检者作为研究对象, 按照年龄分为7组, 收集研究对象一般资料、脊柱骨密度、人血白蛋白、血红蛋白, 采用单因素方差分析、Pearson相关分析、多分类logistic回归模型分析骨密度与血红蛋白、人血白蛋白相关性。结果健康体检者骨密度随年龄增长均降低(P<0.05), 血红蛋白、人血白蛋白、体质指数(BMI)在不同年龄组之间差异均有统计学意义(均P<0.05), 线性相关分析显示不同年龄段男性健康体检者骨密度与血红蛋白呈正相关(分别r=0.086、0.101、0.076、0.090、0.072、0.123、0.100;均P<0.01);而女性健康体检者部分年龄组骨密度与血红蛋白相关(分别40~49岁组:r=-0.027;70~79岁组:r=-0.077;均P<0.05);部分年龄段健康体检者骨密度与血白蛋白相关(其中男性分别为30~39岁组:r=-0.048;40~49岁组r=-0.027;70~79岁组r=-0.051;女性分别为30~39岁组:r=-0.044;40~49岁组r=-0.042;50~59岁组r=-0.086;70~79岁组r=-0.070;均P<0.05)。多分类logistic回归分析显示校正年龄、BMI后血红蛋白水平是男性健康体检者骨密度正常(OR=1.022, 95%CI:1.017~1.027)、骨密度减少(OR=1.012, 95%CI:1.007~1.016)的保护因素;血白蛋白是女性健康体检者骨密度正常(OR=0.926, 95%CI:0.905~0.948)、骨密度减少(OR=1.006, 95%CI:0.951~1.011)危险因素。结论中国健康体检人群骨密度与血红蛋白、人血白蛋白存在相关性。血红蛋白是男性健康体检者骨密度保护因素, 人血白蛋白是女性健康体检者骨密度危险因素。