Research on Preparation and Electrochemical Performance of the High Compacted Density Ni-Co-Mn Ternary Cathode Materials

The high compacted density LiNi0.5-xCo0.2Mn0.3MgxO2 cathode material for lithium-ion batteries was synthesized by high temperature solid-state method, taking the Mg element as a doping element and the spherical Ni0.5Co0.2Mn0.3 (OH)2, Li2CO3 as raw materials. The effects of calcination temperature on the structure and properties of the products were investigated. The structure and morphology of cathode materials powder were analyzed by X-ray diffraction spectroscopy (XRD) and scanning electronmicroscopy (SEM). The electrochemical properties of the cathode materials were studied by charge-discharge test and cyclic properties test. The results show that LiNi0.4985Co0.2Mn0.3 Mg0.0015O2 cathode material prepared at calcination temperature 930°C has a good layered structure, and the compacted density of the electrode sheet is above 3.68 g/cm3. The discharge capacity retention rate is more than 97.5% after 100 cycles at a charge-discharge rate of 1C, displaying a good cyclic performance.

Giant Magneto-Optical Effect in van der Waals Room-Temperature Ferromagnet Fe_(3)GaTe_(2)

The discovery of ferromagnetic two-dimensional(2D)van der Waals(vdWs)materials provides an opportunity to explore intriguing physics and to develop innovative spin electronic devices.However,the main challenge for practical applications of vd Ws ferromagnetic crystals lies in the weak intrinsic ferromagnetism and small perpendicular magnetic anisotropy(PMA)above room temperature.Here,we report the intrinsic vd Ws ferromagnetic crystal Fe_(3)GaTe_(2),synthesized by the self-flux method,exhibiting a Curie temperature(TC)of 370 K,a high saturation magnetization of 33.47 emu/g,and a large PMA energy density of approximately 4.17×10^(5)J/m^(3).Furthermore,the magneto-optical effect is systematically investigated in Fe_(3)GaTe_(2).The doubly degenerate E_(2g)(Γ)mode reverses the helicity of incident photons,indicating the existence of pseudoangular-momentum(PAM)and chirality.Meanwhile,the non-degenerate non-chiral A_(1g)(Γ)phonon exhibits a significant magneto-Raman effect under an external out-of-plane magnetic field.These results lay the groundwork for studying phonon chirality and magneto-optical phenomena in 2D magnetic materials,providing the feasibility for further fundamental research and applications in spintronic devices.

Genome-wide association study identifies novel candidate loci or genes affecting stalk strength in maize

Stalk strength increases resistance to stalk lodging,which causes maize(Zea mays L.)production losses worldwide.The genetic mechanisms regulating stalk strength remain unclear.In this study,three stalk strength-related traits(rind penetrometer resistance,stalk crushing strength,and stalk bending strength)and four plant architecture traits(plant height,ear height,stem diameter,stem length)were measured in three field trials.Substantial phenotypic variation was detected for these traits.A genome-wide association study(GWAS)was conducted using general and mixed linear models and 372,331 single-nucleotide polymorphisms(SNPs).A total of 94 quantitative trait loci including 241 SNPs were detected.By combining the GWAS data with public gene expression data,56 candidate genes within 50 kb of the significant SNPs were identified,including genes encoding flavonol synthase(GRMZM2G069298,ZmFLS2),nitrate reductase(GRMZM5G878558,ZmNR2),glucose-1-phosphate adenylyltransferase(GRMZM2G027955),and laccase(GRMZM2G447271).Resequencing GRMZM2G069298 and GRMZM5G878558 in all tested lines revealed respectively 47 and 2 variants associated with RPR.Comparison of the RPR of the zmnr2EMS mutant and the wild-type plant under high-and low-nitrogen conditions verified the GRMZM5G878558 function.These findings may be useful for clarifying the genetic basis of stalk strength.The identified candidate genes and variants may be useful for the genetic improvement of maize lodging resistance.

Negative-to-Positive Tunnel Magnetoresistance in van der Waals Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)Junctions

The emergent van der Waals magnetic material is a promising component for spintronic devices with novel functionalities.Here,we report a transition of negative-to-positive magnetoresistance in Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)van der Waals all-magnetic tunnel junctions with increasing the applied bias voltage.A negative magnetoresistance is observed first in Fe_(3)GeTe_(2)/Cr_(2)Ge_(2)Te_(6)/Fe_(3)GeTe_(2)tunnel junctions,where the resistance with antiparallel aligned magnetization of two Fe_(3)GeTe_(2)electrodes is lower than that with parallel alignment,which is due to the opposite spin polarizations of two Fe_(3)GeTe_(2)electrodes.With the bias voltage increasing,the spin polarization of the biased Fe_(3)GeTe_(2)electrode is changed so that the spin orientations of two Fe_(3)GeTe_(2)electrodes are the same.Our experimental observations are supported by the calculated spin-dependent density of states for Fe_(3)GeTe_(2)electrodes under a finite bias.The significantly bias voltage-dependent spin transport properties in van der Waals magnetic tunnel junctions open a promising route for designing electrical controllable spintronic devices based on van der Waals magnets.

中国与“一带一路”沿线国家跨国科学研究合作何以可能?——一项定性比较分析

【问题】中国与“一带一路”沿线国家之间的跨国科学研究合作是承载“一带一路”建设科技交流与创新发展使命的重要议题,然而由于许多“一带一路”沿线国家的制度和法律环境尚不健全,甚至部分国家还存在较强的政治风险和文化冲突,这种合作并非易事。在此背景下,中国与“一带一路”沿线国家之间的跨国科学研究合作何以成为可能?【方法】本研究从宏观分析视角提出了中国与“一带一路”沿线国家之间跨国科学研究合作影响因素的分析框架,并采用模糊集定性比较分析方法识别了36个沿线国家案例中的跨国科学研究合作影响因素及其条件组合。【发现】资源投入与制度环境是影响跨国科学研究合作的重要因素,两者相互耦合共同构成跨国科学研究合作的实现路径。进一步地,本研究依据资源投入与制度环境不同耦合程度,识别出强强联合型、资源主导型、经贸带动型与政治兜底型四种跨国科学研究合作类型。【贡献】论文提出的分析框架弥补了以往研究聚焦于中观和微观层面跨国科学研究合作影响因素分析的局限性,区分了不同伙伴国家与中国开展跨国科学研究合作的各种途径,可以更为准确地解释全球治理背景下的跨国科学研究合作机制,对于中国进一步深入推进与沿线国家之间的跨国科学研究合作、提升合作效果具有积极意义。

镍高度分散在铁基钙钛矿用于高温固体氧化物电解池阴极的CO_(2)电催化还原研究

利用太阳能、风能等可再生清洁电能将CO_(2)催化转化为高附加值化学品或燃料,在CO_(2)转化和可再生电能存储方面表现出极具潜力的应用前景.高温固体氧化物电解池(SOEC)可将CO_(2)电催化还原为CO,具有能量效率高、成本低等优点.目前,钙钛矿氧化物已被广泛应用于SOEC电解CO_(2)的阴极材料,但存在电极催化活性低等问题,因而限制其规模化发展和应用.通常采用浸渍、原位溶出或掺杂等策略引入大量活性中心以提升钙钛矿氧化物电极性能.然而,这些策略仍然面临一些挑战,如浸渍法易引入大颗粒物种而堵塞气体传输通道,原位溶出法能耗较大且析出量较少,掺杂法调控活性幅度有限.因此,发展新型简便方法以合理构建具有高度分散活性位点的阴极材料,可有效拓展电化学三相反应界面,进而加快SOEC高温电解CO_(2)的电极动力学速率.本文采用机械研磨法将1.0%NiO高度分散于La_(0.8)Sr_(0.2)FeO_(3)–δ-Ce_(0.8)Sm_(0.2)O_(2)–δ(Ni-LSF-SDC)表面,用作SOEC阴极材料进行CO_(2)电解.扫描电子显微镜(SEM)、透射电子显微镜、扫描透射电子显微镜(STEM)和X射线衍射等结构表征表明,低载量的Ni物种高度分散在LSF-SDC表面,并不会堵塞载体的多孔网络结构,且与钙钛矿镧锶铁(LSF)具有更好的亲和性.X射线光电子能谱和程序升温脱附结果表明,高度分散的Ni物种改善了LSF-SDC的电子结构,不仅提升了体系中电子对的含量,还在体系中形成大量氧空位,显著提升了荷质传递效率.当Ni-LSF-SDC作为SOEC阴极时,在800℃,1.6 V时,CO_(2)电解电流密度最高达到1.53 A·cm^(-2),比未经过Ni修饰的LSF-SDC阴极提高了约91%.同时Ni-LSF-SDC阴极表现出较高的稳定性,在800℃和1.2 V下稳定运行66 h后有微弱的性能衰减,电流衰减率为0.85 mA·cm^(-2)·h^(-1).对稳定性测试后电解池的电极涂覆层截面进行SEM和STEM表征,结果表明,电极表面有少量极小的NiO颗粒形成,且集流体涂覆层的Au元素长时间运行后可迁移到电极内部,这些是导致电解池电解效率衰减的主要因素.总之,本文通过采用一种简便的方法制备出低载量高度分散的Ni修饰铁基钙钛矿阴极材料,高度分散的Ni物种可以调控钙钛矿氧化物载体的电子结构和氧空位浓度,显著提高了SOEC电解CO_(2)性能.本文为合理设计和优化SOEC阴极CO_(2)电催化材料的结构以提升其电催化性能提供了新思路.

低剂量螺旋CT在肺癌筛查中的应用

肺癌是全世界发病率和死亡率最高的恶性肿瘤之一,患者的早期诊断率低、预后差,已造成严重的社会负担。通过低剂量螺旋计算机断层扫描(low-dose spiral computed tomography,LDCT)对高危人群进行定期筛查的方法能够显著提高肺癌的早期诊断率,为肺癌的诊疗带来了新机遇。近年来,全世界多个国家开展了LDCT肺癌筛查项目并取得了良好的效果,但在筛查主体的选择、筛查频率、成本效能等方面也存在一些争议。本文将从LDCT肺癌筛查的关键因素、筛查效果、肺结节的管理和人工智能对于LDCT的发展贡献等方面进行综述,探讨LDCT在肺癌筛查中的应用进展。

Risk factors and long-term health consequences of macrosomia:a prospective study in Jiangsu Province,China

We sought to determine risk factors associated with fetal macrosomia and to explore the long-term consequence of infant macrosomia at the age of 7 years.A prospective population based cohort study was designed to examine the associations between maternal and perinatal characteristics and the risk of macrosomia.A nested case-control study was conducted to explore the long-term health consequence of infant macrosomia.The mean maternal age of the macrosomia group was 24.74±3.32 years,which is slightly older than that in the control group（24.35±3.14 years,P = 0.000）.The mean maternal body mass index（BMI） at early pregnancy was 22.75±2.81 kg/m 2,which was also higher than that in the control group（21.76±2.59 kg/m 2,P = 0.000）.About 64.6% of macrosomic neonates were males,compared with 51.0% in the control group（P = 0.000）.Compared with women with normal weight（BMI：18.5-23.9 kg/m 2）,women who were overweight（BMI：24-27.9 kg/m 2） or obese（BMI ≥ 28 kg/m 2）,respectively,had a 1.69-fold（P = 0.000） and a 1.49-fold（P = 0.000） increased risks of having a neonate with macrosomia,while light weight（BMI〈18.5 kg/m 2） women had an approximately 50% reduction of the risk.Furthermore,macrosomia infant had a 1.52-fold and 1.50-fold risk,respectively,of developing overweight or obesity at the age of 7 years（P = 0.001 and P = 0.000）.Older maternal age,higher maternal BMI at early pregnancy and male gender were independent risk factors of macrosomia.Macrosomic infant was associated with an increased predisposition to develop overweight or obesity at the beginning of their childhood.

Improving the performance of solid oxide electrolysis cell with gold nanoparticles-modified LSM-YSZ anode

Gold, as the common current collector in solid oxide electrolysis cell(SOEC), is traditionally considered to be inert for oxygen evolution reaction at the anode of SOEC. Herein, gold nanoparticles were loaded onto conventional strontium doped lanthanum manganite-yttria stabilized zirconia(LSM-YSZ) anode, which evidently improved the performance of oxygen evolution reaction at 800 °C. The current densities at 1.2 V and 1.4 V increased by 60.0% and 46.9%, respectively, after loading gold nanoparticles onto the LSM-YSZ anode. Physicochemical characterizations and electrochemical measurements suggested that the improved SOEC performance was attributed to the accelerated electron transfer of elementary process in anodic polarization reaction and the newly generated triple phase boundaries in gold nanoparticles-loaded LSMYSZ anode.

Co-electrolysis of CO_2 and H_2O in high-temperature solid oxide electrolysis cells: Recent advance in cathodes

Co-electrolysis of CO2and H2O using high-temperature solid oxide electrolysis cells(SOECs) into valuable chemicals has attracted great attentions recently due to the high conversion and energy efficiency,which provides opportunities of reducing CO2emission, mitigating global warming and storing intermittent renewable energies. A single SOEC typically consists of an ion conducting electrolyte, an anode and a cathode where the co-electrolysis reaction takes place. The high operating temperature and difficult activated carbon-oxygen double-bond of CO2put forward strict requirements for SOEC cathode. Great efforts are being devoted to develop suitable cathode materials with high catalytic activity and excellent long-term stability for CO2/H2O electro-reduction. The so far cathode material development is the key point of this review and alternative strategies of high-performance cathode material preparation is proposed. Understanding the mechanism of CO2/H2O electro-reduction is beneficial to highly active cathode design and optimization. Thus the possible reaction mechanism is also discussed. Especially, a method in combination with electrochemical impedance spectroscopy(EIS) measurement, distribution functions of relaxation times(DRT) calculation, complex nonlinear least square(CNLS) fitting and operando ambient pressure X-ray photoelectron spectroscopy(APXPS) characterization is introduced to correctly disclose the reaction mechanism of CO2/H2O co-electrolysis. Finally, different reaction modes of the CO2/H2O coelectrolysis in SOECs are summarized to offer new strategies to enhance the CO2conversion. Otherwise,developing SOECs operating at 300-600 °C can integrate the electrochemical reduction and the Fischer-Tropsch reaction to convert the CO2/H2O into more valuable chemicals, which will be a new research direction in the future.

Infiltration of Ce0.8Gd0.2O1.9 nanoparticles on Sr2Fe1.5Mo0.5O6-δ cathode for CO2 electroreduction in solid oxide electrolysis cell

Solid oxide electrolysis cell(SOEC) can electrochemically convert CO2 to CO at the gas-solid interface with a high current density and Faradaic efficiency, which has attracted increasing attentions in recent years.Exploring efficient catalyst for electrochemical CO2 reduction reaction(CO2 RR) at the cathode is a grand challenge for the research and development of SOEC. Sr2Fe1.5Mo0.5O6-δ(SFM) is one kind of promising cathode materials for SOEC, but suffers from insufficient activity for CO2 RR. Herein, Gd0.2Ce0.8O1.9(GDC)nanoparticles were infiltrated onto the SFM surface to construct a composite GDC-SFM cathode and improve the CO2 RR performance in SOEC. The current density over the GDC infiltrated SFM cathode with a GDC loading of 12.8 wt% reaches 0.446 A cm-2 at 1.6 V and 800 °C, which is much higher than that over the SFM cathode(0.283 A cm-2). Temperature-programmed desorption of CO2 measurements suggest that the infiltration of GDC nanoparticles significantly increases the density of surface active sites and three phase boundaries(TPBs), which are beneficial for CO2 adsorption and subsequent conversion. Electrochemical impedance spectroscopy results indicate that the polarization resistance of 12.8 wt% GDCSFM cathode was obviously decreased from 0.46 to 0.30 cm^2 after the infiltration of GDC nanoparticles.

Large Room-Temperature Magnetoresistance in van der Waals Ferromagnet/Semiconductor Junctions

A magnetic tunnel junction(MTJ)is the core component in memory technologies,such as the magnetic random-access memory,magnetic sensors and programmable logic devices.In particular,MTJs based on twodimensional van der Waals(vd W)heterostructures offer unprecedented opportunities for low power consumption and miniaturization of spintronic devices.However,their operation at room temperature remains a challenge.Here,we report a large tunnel magnetoresistance(TMR)of up to 85%at room temperature(T=300 K)in vdW MTJs based on a thin(<10 nm)semiconductor spacer WSe_(2)layer embedded between two Fe_(3)GaTe_(2e)lectrodes with intrinsic above-room-temperature ferromagnetism.The TMR in the MTJ increases with decreasing temperature up to 164%at T=10 K.The demonstration of TMR in ultra-thin MTJs at room temperature opens a realistic and promising route for next-generation spintronic applications beyond the current state of the art.

A novel proton-gradient-transfer acid complexes as an efficient and reusable catalyst for fatty acid esterification

In this work,a series of novel proton-gradient-transfer acid complexes(PGTACs)were developed.Their physicochemical properties,including thermal stability,melting point,and Hammett acidity,were measured.The effects of catalyst loading,reaction temperature,and substrate expansion on the catalytic performance were systematically studied.It is found that the combination of bidentate N-heterocycle and H;SO;(1:2 M ratio)could form simultaneously N–H covalent bond and N…H hydrogen bond,which makes the PGTACs excellent catalysts integrate the advantages of strong acids(high catalytic activity)and ionic liquids(phase separation)in the esterification reaction.Moreover,these PGTACs can be reused by convenient phase separation without obvious diminution of catalytic activity.It is concluded that these PGTACs are potential alternative candidates for esterification reaction in the process of industrial catalysis.

液体活检在小细胞肺癌诊疗中的应用研究进展

小细胞肺癌(small cell lung cancer,SCLC)是一种侵袭性强、死亡率高的恶性肿瘤,具有易转移、生长速度快、恶性程度高和侵袭性强等特点,患者预后一般较差。目前SCLC的临床诊断方法主要以组织活检为主,创伤大、周期长且成本高。近年来,液体活检以传统组织活检所不具备的无创性、全面性、实时性等优良特点而逐渐获得应用。液体活检的主要检测对象包括外周血中的循环肿瘤DNA(circulating tumor DNA,ctDNA)、循环肿瘤细胞(circulating tumors cells,CTCs)及外泌体等。将液体活检应用于SCLC的临床治疗,有助于提高临床医生对SCLC患者病情的详细诊断,以及对患者治疗反应的及时掌控和应对。

Preparation and Properties of Bio-Based Flame Retardant Polyvinyl Alcohol

Polyvinyl alcohol (PVA) has been widely used in the fields of medical, food and packaging due to its excellentbiocompatibility, good fiber-forming and film-forming properties. However, the high flammability of PVA hasgreatly limited its wider applications. The flame-retardant PVA was prepared by melt blending of a bio-basedflame retardant (prepared from lignin, phosphoric acid and carbamide) with thermoplastic PVA (TPVA). Thechemical structure, morphology, thermal properties, mechanical properties, fire property and fluidity of thisflame retardant PVA were investigated by Fourier transform infrared spectrometer(FTIR), field emission scanning electron microscope(SEM), thermogravimetric analyzer(TGA), impact tester, universal testing machine,horizontal-vertical burning tester, limiting oxygen indexer(LOI) and melt flow rate meter(MFR). The resultsshowed that the prepared flame retardant had good compatibility with the PVA substrate;The impact strength,melt flow rate, fire property and char residue of this PVA material increased with the content of bio-based flameretardant. When the content of flame retardant was of 20%, the five indices including impact strength, meltflow rate, UL-94 level, LOI and char residual were 11.3 KJ/m^(2), 21.2 g/10 min, V-0 UL-94 level, 33.1%, and19.2%, respectively. This research can promote the high-value utilization of lignin and the application ofPVA in the fields of fire protection.

山西猪场猪蓝耳病并发猪胸膜肺炎放线杆菌的病毒鉴定及细菌分离鉴定以及治疗方案

2020年2月份山西某大型规模猪场育肥猪突发呼吸困难,无过多症状表现,即突然死亡,发病率为2%,死亡率1.5%左右。实验室以病死猪为研究对象,综合死亡猪只脏器病变状况观察,无菌采集病死猪的肺脏、肝脏、脾脏病料,进行RT-PCR检测猪蓝耳病原;用含1%NAD和5%胎牛血清的TSA琼脂培养基进行细菌分离培养和纯化,经形态学鉴定、PCR鉴定、16Sr RNA基因序列进化树构建等方法,结果显示:该发病猪群为猪繁殖与呼吸障碍综合征并发猪胸膜肺炎放线杆菌感染。药敏试验结果显示:该猪胸膜肺炎放线杆菌对安普霉素、硫酸黏菌素、替米考星+氟苯尼考、替米考星+阿莫西林、氟苯尼考、头孢噻呋钠+硫酸黏菌素、头孢喹肟、头孢噻呋钠+新霉素、替米考星+头孢噻呋钠、多西环素+氟苯尼考、头孢噻呋钠+阿莫西林、阿莫西林+克拉维酸钾、头孢噻呋钠+恩诺沙星、新霉素、头孢噻呋钠、安普霉素+头孢噻呋钠敏感。对恩诺沙星耐药。本实验室根据临床及检测结果制定治疗方案,为该猪场的猪繁殖与呼吸障碍综合征并发猪胸膜肺炎的临床诊断及用药提供了理论依据。

Intrinsic fluctuation and susceptibility in somatic cell reprogramming process

Based on the coherent feedforward transcription regulation loops in somatic cell reprogramming process, a stochastic kinetic model is proposed to study the intrinsic fluctuations in the somatic cell reprogramming. The Fano factor formulas of key genes expression level in the coherent feedforward transcription regulation loops are derived by using of Langevin theory. It is found that the internal fluctuations of gene expression levels mainly depend on itself activation ratio and degradation ratio. When the self-activation ratio(or self-degradation ratio) is increased, the Fano factor increases reaches a maximum and then decreases. The susceptibility is used to measure the sensitivity of steady-state response to the variation in systemic parameters. It is found that with the increase of the self-activation ratio(or self-degradation ratio), the susceptibility of steady-state increases at first, it reaches a maximum, and it then decreases. The magnitude of the maximum is increased with the increase of activated ratio by the upstream transcription factor.

Efficient conversion of H_(2)S into mercaptan alcohol by tertiary-amine functionalized ionic liquids

The resource utilization of hydrogen sulfide(H_(2)S)is of great significance in natural gas chemical industry.Described herein have developed a novel method mediated in tertiary amine-functionalized ionic liquids(ILs)to convert H_(2)S into mercaptan alcohols with enols.The effect of ILs,substra te scope,and regeneration experiments have been investigated.It is found that the conversion of 3-methyl-2-buten-1-ol by H_(2)S can reach 52%with a 50%(mol)catalyst loading of bis(2-dimethylaminoethyl)ether methoxyacetate within 12 hat 90℃.The reaction mechanism was speculated based on theoretical calculation.Besides,a plausible reaction-separation-integrated strategy was further proposed.This work reveals an effective insight into the capture and catalytic conversion of H_(2)S to high valuable mercaptan alcohol,which makes the utilization method of H_(2)S resource universal and has the potentiality for industrial application.

Astaxanthin delayed the pathogenesis of diabetic nephropathy in type 1 diabetic rats

This study was designed to investigate the protective effects of Astaxanthin(AST)in rats with diabetes mellitus(DM)induced by streptozotocin.SD rats were divided into control group(n=5,only received normal saline),DM group(n=8)and AST+DM group(n=8;AST:50 mg/kg/day).DM rats were induced by intraperitoneal injection of streptozocin(STZ,65 mg/kg).Blood glucose level and body weight were determined at weeks 0,2,4,6 and 8,respectively.At week 8,kidney function was determined,together with expression of P53 and dynamin-related protein-1(Drp1)by Western blot analysis and immunofluorescence.AST led to increase of body weight in rats with DM.AST+DM group showed a significant decrease in blood glucose level at week 4 compared with DM group(P<0.05).AST improved renal function and significantly reduced expression of P53 and Drp1 in DM rats.In addition,AST can effectively reduce the blood glucose in DM rats,and delayed the pathogenesis of diabetic nephropathy.Such delay mediated by AST may be associated with the downregulation of Drp1 and P53.

Role of Nanfan Base and Recommendations about Construction and Management

This paper first analyzes the important role of Nanfan Base in China: " accelerator" for breeding new varieties of crops; " unallocated store" to ensure the varieties for agricultural production; " lightning rod" to ensure the quality and safety of seeds; " big stage" for variety and technical exchanges and cooperation; " big school" for cultivating seed industry technology talents; " booster" for promoting local economic development. Then it points out the main problems about Nanfan Base and finally sets forth the relevant recommendations.