Methanation of carbon dioxide on Ni/ZrO_2-Al_2O_3 catalysts:Effects of ZrO_2 promoter and preparation method of novel ZrO_2-Al_2O_3 carrier

The novel nickel-based catalysts with a nickel content of 12 wt% were prepared with the zirconia-alumina composite as the supports. The new carriers, ZrO2 improved alumina, were synthesized by three methods, i.e., impregnation-precipitation, co-precipitation, and impregnation method. The catalytic properties of these catalysts were investigated in the methanation of carbon dioxide, and the samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscope （XPS）, temperature-programmed reduction （TPR） and temperature-programmed desorption （TPD） techniques. The new catalysts showed higher catalytic activity and better stability than Ni/γ-Al2O3. Furthermore, as a support for new nickel catalyst, the ZrO2-Al2O3 composite prepared by the impregnation-precipitation method was more efficient than the other supports in the methanation of carbon dioxide. The highly dispersed zirconium oxide on the surface of γ-Al2O3 inhibited the formation of nickel aluminate-like phase, which was responsible for the better dispersion of Ni species and easier reduction of NiO species, leading to the enhanced catalytic performance of corresponding catalyst.

Maternal-derived antibodies hinder the antibody response to H9N2 AIV inactivated vaccine in the field

The H9N2 subtype avian influenza virus(AIV)inactivated vaccine has been used extensively in poultry farms,but it often fails to stimulate a sufficiently high immune response in poultry in the field,although it works well in laboratory experiments;hence,the virus still causes economic damage every year and poses a potential threat to public health.Based on surveillance data collected in the field,we found that broilers with high levels of maternal-derived antibodies(MDAs)against H9N2 virus did not produce high levels of antibodies after vaccination with a commercial H9N2 inactivated vaccine.In contrast,specific pathogen-free(SPF)chickens without MDAs responded efficiently to that vaccination.When MDAs were mimicked by administering passively transferred antibodies(PTAs)into SPF chickens in the laboratory,similar results were observed:H9N2-specific PTAs inhibited humoral immunity against the H9N2 inactivated vaccine,suggesting that H9N2-specific MDAs might hinder the generation of antibodies when H9N2 inactivated vaccine was used.After challenge with homologous H9N2 virus,the virus was detected in oropharyngeal swabs of the vaccinated and unvaccinated chickens with PTAs but not in the vaccinated chickens without PTAs,indicating that H9N2-specific MDAs were indeed one of the reasons for H9N2 inactivated vaccine failure in the field.When different titers of PTAs were used to mimic MDAs in SPF chickens,high(HI=12 log2)and medium(HI=log 9 log2)titers of PTAs reduced the generation of H9N2-specific antibodies after the first vaccination,but a booster dose would induce a high and faster humoral immune response even of PTA interference.This study strongly suggested that high or medium titers of MDAs might explain H9N2 inactivated vaccine failure in the field.

Bio-Master:Design and Validation of a High-Throughput Biochemical Profiling Platform for Crop Canopies

Accurate assessment of crop biochemical profiles plays a crucial role in diagnosing their physiological status.The conventional destructive methods,although reliable,demand extensive laboratory work for measuring various traits.On the other hand,nondestructive techniques,while efficient and adaptable,often suffer from reduced precision due to the intricate interplay of the field environment and canopy structure.Striking a delicate balance between efficiency and accuracy,we have developed the Bio-Master phenotyping system.This system is capable of simultaneously measuring four vital biochemical components of the canopy profile:dry matter,water,chlorophyll,and nitrogen content.Bio-Master initiates the process by addressing structural influences,through segmenting the fresh plant and then further chopping the segment into uniform small pieces.Subsequently,the system quantifies hyperspectral reflectance and fresh weight over the sample within a controlled dark chamber,utilizing an independent light source.The final step involves employing an embedded estimation model to provide synchronous estimates for the four biochemical components of the measured sample.In this study,we established a comprehensive training dataset encompassing a wide range of rice varieties,nitrogen levels,and growth stages.Gaussian process regression model was used to estimate biochemical contents utilizing reflectance data obtained by Bio-Master.Leave-one-out validation revealed the model's capacity to accurately estimate these contents at both leaf and plant scales.With Bio-Master,measuring a single rice plant takes approximately only 5 min,yielding around 10 values for each of the four biochemical components across the vertical profile.Furthermore,the Bio-Master system allows for immediate measurements near the field,mitigating potential alterations in plant status during transportation and processing.As a result,our measurements are more likely to faithfully represent in situ values.To summarize,the Bio-Master phenotyping system offers an efficient tool for comprehensive crop biochemical profiling.It harnesses the benefits of remote sensing techniques,providing significantly greater efficiency than conventional destructive methods while maintaining superior accuracy when compared to nondestructive approaches.

Water-soluble ions in hailstones in northern and southwestern China

Natural hailstones were collected and analyzed in the laboratory not only for their physical properties (e.g., structure, density,shape, and air bubbles), but also for their chemical properties(e.g., organic particles, biological particles, and water-soluble ions),which can help a clear understanding on microphysics and development of hailstorms [1–4]. Aerosol particles were carried up from the atmospheric boundary layer to the free atmosphere into

表面化学调控无机固体相变与智能应用

低维无机固体材料中电子-电子关联作用导致了许多新奇的相变行为,如金属-绝缘体转变、超导、电荷密度波和巨磁阻效应等.外场调节参量可以改变有序相间的平衡关系,实现不同相之间的转变,诱导新的物理内容甚至全新的量子临界现象,具有巨大的潜力应用于未来先进电子元件和智能响应器件.低维无机相变固体具有极大的比表面积和电子关联性,表面化学修饰为调控其相变和复杂相互作用打开了新的研究空间,有助于低维关联电子体系物理规律和新量子序的探索,对理解这些复杂物理现象的微观起源具有重要意义.本文概述了近年来发展的表面化学修饰策略调控低维无机固体相变的系列进展,并以此探究维度受限下相变固体对外界光和磁等的智能响应特性.