Characteristics and mechanism of Ni^(2+)and Cd^(2+)adsorption by recovered perlite from agar extraction residue

Ni^(2+)and Cd^(2+)in wastewater accumulated through the ecological chain and could jeopardize human health.Adsorption of Ni^(2+)and Cd^(2+)from wastewater using recovered perlite was an important way to solve the problem of resource utilization of solid waste from agar production.Our previous study confirmed that recovered perlite from agar extraction residue had better pore size and specific surface area than commercial perlite.However,the adsorption efficiency and adsorption mechanism of recovered perlite were the main factors limiting its adsorption application.The adsorption process of Ni^(2+)and Cd^(2+)by recovered perlite in aqueous solution was described by the pseudo-second-order kinetic equation,and the relevant adsorption mechanism was mainly chemisorption.Compared with commercial perlite,the adsorption removal rate of Ni^(2+)and Cd^(2+)by enzymatic recovered perlite could reach 92.9%and 89.2%,respectively,and were improved by 12.63%and 13.03%.Langmuir isothermal adsorption model could better describe the isothermal adsorption process of recovered perlite on heavy metal Ni^(2+)and Cd^(2+),and the relevant adsorption mechanism was mainly monolayer adsorption.The X-ray photoelectron spectroscopy(XPS)results indicated that the decrease of Si—O Si^(2+)hydroxyl coordination bond and the increase of C—Si bond might make the binding effect of recovered perlite with heavy metals stronger.The competitive adsorption of Ni^(2+)and Cd^(2+)by recovered perlite was still dominated by chemisorption and monolayer adsorption.This study was expected to provide a theoretical basis and technical support for the removal of Ni^(2+)and Cd^(2+)from wastewater using recovered perlite from seaweed residue.

Mixing of miscible shear-thinning fluids in a lid-driven cavity

The concentration and velocity fields of two refractive index matched miscible shear-thinning fluids in a lid-driven cavity were investigated by using planar laser-induced fluorescence and particle image velocimetry,as well by computational fluid dynamics.Quantitative analyses show that the results obtained by flow simulations with the species transport model are in good agreement with the experimental results.The effects of different parameters were studied by using the intensity of segregation.For two fluids with the same rheological parameters,the relative amounts of liquids H_(1)/H and the power-law index n dominate the mixing process while the Reynolds number Re plays a marginal role.As for two fluids with density difference,buoyancy has significant influence on the mixing process.The dimensionless group Ar/Re(redefined such as to include shear thinning behavior)is proposed for assessing the effect of buoyancy and rheological properties on the mixing of miscible shear-thinning fluids.

Compressibility induced bubble size variation in bubble column reactors:Simulations by the CFD–PBE

Bubble column reactors can be simulated by the two fluid model(TFM) coupled with the population balance equation(PBE). For the large industrial bubble columns, the compressibility due to the pressure difference may introduce notable bubble size variation. In order to address the compressibility effect, the PBE should be reformulated and coupled with the compressible TFM. In this work, the PBE with a compressibility term was formulated from single bubble dynamics, the mean Sauter diameters predicted by the compressible TFM coupled with the PBE were compared with the analytical solutions obtained by the ideal gas law. It was proven that the mesoscale formulations presented in this work were physically consistent with the macroscale modeling. It can be used to simulate large industrial plants when the compressibility induced bubble size variation is important.

文夜蛾亚科第一个完整的线粒体基因组描述及系统发育分析(鳞翅目:夜蛾科)

夜蛾科是鳞翅目中物种数量最多的科。夜蛾科的一些蛾类昆虫是作物上的重要害虫。然而,目前缺乏夜蛾科中文夜蛾亚科的线粒体基因组序列。本研究以标瑙夜蛾为代表,报道了文夜蛾亚科第1个线粒体全基因组序列。标瑙夜蛾的线粒体基因组全长为15,430 bp,包含13个蛋白质编码基因、2个核糖体RNA基因和22个转运RNA基因以及1个非编码控制区。本文使用夜蛾科中的60个物种为内群研究对象,并选取2个尾夜蛾科昆虫作为外群,分别使用最大似然法和贝叶斯法构建夜蛾科的系统发育关系。系统发育树显示,金翅夜蛾亚科、青夜蛾亚科、实夜蛾亚科、冬夜蛾亚科、夜蛾亚科、Ipimorphinae和文夜蛾亚科为单系群,而盗夜蛾亚科、木夜蛾亚科、剑纹夜蛾亚科和杂夜蛾亚科为非单系群。本研究旨在通过对线粒体基因组数据的分析,研究夜蛾科中各亚科之间的系统发育关系,并阐明标瑙夜蛾的系统发育地位。

液体门控机制及基本性质测定——化学“101计划”表界面性质测量实验新设计

介绍一个涵盖界面化学、物理化学与仪器分析等多学科的基础实验。本实验融合前沿科技成果“液体门控技术”,以自主研发的液体门控教学测试分析仪(压力阈值仪)的设计原理和先进表征技术特性为基础,结合本科生化学“101计划”中的化学测量学实验——液体门控机制及基本性质测定,创新教学模式,丰富化学测量学实验中关于界面科学表征的课程设计。

Recent advances in design of hydrogen evolution reaction electrocatalysts at high current density:A review

The electrolysis of water powered by renewable energy sources offers a promising method of"green hydrogen"production,which is considered to be at the heart of future carbon-neutral energy systems.In the past decades,researchers have reported a number of hydrogen evolution reaction(HER)electrocatalysts with activity comparable to that of commercial Pt/C,but most of them are tested within a small current density range,typically no more than 500 mA cm^(-2).To realize the industrial application of hydrogen production from water electrolysis,it is essential to develop high-efficiency HER electrocatalysts at high current density(HCD≥500 mA cm^(-2)).Nevertheless,it remains challenging and significant to rational design HCD electrocatalysts for HER.In this paper,the design strategy of HCD electrocatalysts is discussed,and some HCD electrocatalysts for HER are reviewed in seven categories(alloy,metal oxide,metal hydroxide,metal sulfide/selenide,metal nitride,metal phosphide and other derived electrocatalysts).At the end of this article,we also pro-pose some viewpoints and prospects for the future development and research directions of HCD electrocatalysts for HER.

农户生态耕种的现状与激励对策——基于江西省2028户农户化肥农药使用行为的专题调研

作为耕地的耕种主体,农户的生态耕种行为,不仅是发展现代生态农业、促进生态文明建设的客观要求,也是实现耕地数量质量生态'三位一体'保护目标的内在需求。针对化肥农药的滥用是当前威胁生态耕种最突出因素这一现实问题,本文基于江西省2 028份问卷调研,系统分析了现阶段农户化肥农药使用现状,并在尊重农户对激励措施愿望的基础上,提出促进农户合理使用化肥农药的激励对策。研究表明:农户的生态耕种形势不容乐观,农户虽然普遍认识到过量使用化肥农药对生态环境产生的危害,但大部分农户在确定化肥农药使用量时缺乏科学依据,存在化肥农药使用量逐年增加的趋势。为此,研究提出激励农户合理使用化肥农药的对策建议:一是正视化肥农药使用的经济外部性,把农户合理使用化肥农药激励融入国家惠农政策目标之中;二是重视化肥农药基本知识的宣传,促进农户养成良好施肥习惯;三是回归基层农业技术推广的本质职能,发挥政府在农业技术推广中的主体作用;四是加大以测土配方施肥为代表的科学施肥技术推广应用,提升化肥使用效率;五是培育新型农民与鼓励适度规模经营并举,优化合理使用化肥农药的环境;六是完善冬季绿肥种植的激励对策,切实调动农户绿肥种植的积极性。

“确权确股不确地”承包地经营权流转研究——基于江西省黄溪村实践的调研

在承包权和经营权分离基础上的耕地经营权流转是协调我国家庭承包责任制分散承包与现代农业生产规模经营之间矛盾的根本途径。'确权确股不确地'承包地经营权流转是近年来广受争议的一种流转模式,本文对江西省修水县黄溪村2009年开始进行的'确权确股不确地'实践探索进行系统分析,以期为其推广应用价值的评判提供科学依据。研究表明,'确权确股不确地'不仅实现了耕地承包权与经营权的分离,促进了耕地的规模经营,推动了农村劳动力的转移,而且实现了农户承包经营权的保值增值,农村土地管理从被动转为主动;但存在可持续的运行机制尚未构建、耕地的非粮化潜在威胁增强、农户承包经营权的融资功能实现难度增大、现有的农业补偿政策难以发挥应有的激励作用等问题。'确权确股不确地'承包地经营权流转必须具备'村集体组织建设是核心、完善的配套管理制度是保障、培育多种现代农业经营主体是前提、实施土地整治是重要条件'的运行环境。

一维光子晶体能带结构的电光特性研究

采用有限元法对一维掺镧锆钛酸铅光子晶体的能带特性进行分析。当给一维掺镧锆钛酸铅光子晶体施以外加电场时,由于介质掺镧锆钛酸铅的电光效应引起折射率变化,使得一维掺镧锆钛酸铅光子晶体的能带结构发生变化。详细分析了外加电场变化对一维掺镧锆钛酸铅光子晶体的禁带结构特性的影响,禁带的中心波长及禁带宽度的变化量与电场呈四次函数关系。

Quadrature-based moment methods for the population balance equation: An algorithm review

The dispersed phase in multiphase flows can be modeled by the population balance model(PBM). A typical population balance equation(PBE) contains terms for spatial transport, loss/growth and breakage/coalescence source terms. The equation is therefore quite complex and difficult to solve analytically or numerically. The quadrature-based moment methods(QBMMs) are a class of methods that solve the PBE by converting the transport equation of the number density function(NDF) into moment transport equations. The unknown source terms are closed by numerical quadrature. Over the years, many QBMMs have been developed for different problems, such as the quadrature method of moments(QMOM), direct quadrature method of moments(DQMOM),extended quadrature method of moments(EQMOM), conditional quadrature method of moments(CQMOM),extended conditional quadrature method of moments(ECQMOM) and hyperbolic quadrature method of moments(Hy QMOM). In this paper, we present a comprehensive algorithm review of these QBMMs. The mathematical equations for spatially homogeneous systems with first-order point processes and second-order point processes are derived in detail. The algorithms are further extended to the inhomogeneous system for multiphase flows, in which the computational fluid dynamics(CFD) can be coupled with the PBE. The physical limitations and the challenging numerical problems of these QBMMs are discussed. Possible solutions are also summarized.

Synthesis and Photocatalytic Activity of One-Dimensional CdS@TiO_2 Core-Shell Hetero-structures

One-dimensional Cd S@TiO_2 core-shell heterostructures were fabricated via the hydrolysis of tetrabutyl titanate(TBT) on preformed Cd S nanowires. The as-prepared products were characterized by X-ray diffraction, transmission electron microscopy, selected area electron diffraction and diffuse reflectance spectroscopy techniques. Results demonstrated that the hydrolysis of TBT had a great influence on the morphology of the coated TiO_2 shell, resulting in the formation of TiO_2 nanoparticles and nanolayer-modified Cd S@TiO_2 heterostructures. Degradation of methylene blue using Cd S@TiO_2 core-shell heterostructures as photocatalysts under visible light irradiation was investigated. Comparative photocatalytic tests showed that the TiO_2 nanoparticles-modified heterostructure exhibited a superior activity due to the passivity of photogenerated charge carriers.

Impacts of different methylprednisolone administration routes in patients with sudden hearing loss or Meniere’s disease

Background:Evidence suggests that glucocorticoids are important in the treatment of sudden hearing loss(SHL)and Meniere’s disease(MD).However,different glucocorticoid administration methods may have a significant impact on treatment outcomes.Objective:This study aimed to investigate effects of different glucocorticoid administration methods on sudden hearing loss and Meniere’s disease.Methods:In this study,glucocorticoids were administered orally in 18 patients,by retroauricular injection in 15 patients and by intratympanic injection in 15 patients.White blood cell(WBC)count,serum Kt,fasting plasma glucose(FPG),body temperature,heart rate and blood pressure were used to evaluate effects of glucocorticoids on patients with hearing loss.Visual analog scale(VAS)of pain and sleep disorders were also surveyed,and pure tone audiometry(PTA)results were compared among groups to evaluate efficacy of different glucocorticoids administration methods.Result:WBC count,heart rate and blood pressure were higher in patients taking oral glucocorticoids,while body temperature,serum Kt and FPG levels did not change in all three groups.However,patients who received intratympanic injection of glucocorticoids experienced more pain,while those taking oral glucocorticoids reported more sleep impairment.Treatment efficacy on hearing loss was not significantly different among the three groups.Conclusion:These findings suggest that systemic glucocorticoid administration can result in greater whole body responses than local administration,but with similar hearing treatment efficacy.

Effects of dietary replacement of soybean meal with dried distillers grains with solubles on the microbiota occupying different ecological niches in the rumen of growing Hu lambs

Background:Diet has a profound impact on the rumen microbiota,and the impact can vary among the different rumen ecological niches(REN).This study investigated the effects of dietary replacement of soybean meal(SBM)with dried distillers grains with solubles(DDGS)on the rumen microbiota occupying different REN of growing Hu lambs.After a 9-week feeding trial,6 lambs from each dietary treatment(SBM vs.DDGS-based diets)were slaughtered for sample collection.The microbiota of the rumen solid,liquid,and epithelium fractions was examined using amplicon sequencing analysis of bacterial 16S rRNA gene,functional prediction,and qPCR.Results:No interaction of dietary protein source(PS)and REN were detected for virtually all the measurements made in this study.The DDGS substitution resulted in very limited influence on bacterial community structure.However,the metabolic pathways predicted from 16S rRNA gene sequences varied greatly between SBM-and DDGS-based diets.The populations of rumen total bacteria,fungi,sulfate-reducing bacteria(SRB),and methanogens were not influenced by DDGS substitution,but the population of protozoa was reduced.The bacterial communities in rumen solid(RS)and liquid(RL)were similar in taxonomic composition but were different in relative abundance of some taxa.In contrast,the bacterial composition and relative abundance of rumen epithelium(RE)were greatly distinct from those of the RS and the RL.In alignment with the bacterial relative abundance,the metabolic pathways predicted from 16S rRNA genes also varied greatly among the different REN.The populations of total bacteria,protozoa,and methanogens attached to the RE were smaller than those in the RS and RL,and the fungal population on the rumen epitheliumwas smaller than that in the RS but similar to that in the RL.On the contrary,the SRB population on the RE was greater than that in the RS and RL.Conclusions:Substitution of SBM with DDGS had greater impact to the protozoa than to the other microbes,and the microbial community structure and functions at different REN are distinct and niche-adapted.

Investigation of extraction fraction in confined impinging jet reactors for tri-butyl-phosphate extracting butyric acid process

The extraction fraction E and overall volumetric mass transfer coefficient kka of TBP extracting butyric acid pro- cess in confined impinging jet reactors （CIJR） with two jets were investigated. The main variables tested were the concentration of tri-butyl-phosphate （TBP） and butyric acid, the impinging velocity V, the impinging velocityratio of two phases Vorg/Vaq, the nozzle inner diameter di and the distance L between the jet axes and the top wall of the impinging chamber. The results showed that E and kLa increase with an increase of the impinging velocity V, the concentration ofTBP Corg, and the impinging velocity ratio Vor/Vaq. However, E and kta decrease with an increase of the inner diameter d1 from 1 to 2 mm, the concentration of butyric acid Caq from 0.5% （v/v） to 2% （v/v）. The factor L ranging from 3 to 11 mm has a negligible effect on E and kLa. A correlation on these variables and kLa was proposed based on the experimental data. These results indicated good mass transfer oerformance of CIJR in the extraction operation.

Computer Aided Design Technology for Convex Faceted Gem Cuts Based on the Half-Edge Data Structure

Aiming to increase the efficiency of gem design and manufacturing, a new method in computer-aided-design (CAD) of convex faceted gem cuts (CFGC) based on Half-edge data structure (HDS), including the algorithms for the implementation is presented in this work. By using object-oriented methods, geometrical elements of CFGC are classified and responding geometrical feature classes are established. Each class is implemented and embedded based on the gem process. Matrix arithmetic and analytical geometry are used to derive the affine transformation and the cutting algorithm. Based on the demand for a diversity of gem cuts, CAD functions both for free-style faceted cuts and parametric designs of typical cuts and visualization and human-computer interactions of the CAD system including two-dimensional and three-dimensional interactions have been realized which enhances the flexibility and universality of the CAD system. Furthermore, data in this CAD system can also be used directly by the gem CAM module, which will promote the gem CAD/CAM integration.

Future Event Prediction Based on Temporal Knowledge Graph Embedding

Accurate prediction of future events brings great benefits and reduces losses for society in many domains,such as civil unrest,pandemics,and crimes.Knowledge graph is a general language for describing and modeling complex systems.Different types of events continually occur,which are often related to historical and concurrent events.In this paper,we formalize the future event prediction as a temporal knowledge graph reasoning problem.Most existing studies either conduct reasoning on static knowledge graphs or assume knowledges graphs of all timestamps are available during the training process.As a result,they cannot effectively reason over temporal knowledge graphs and predict events happening in the future.To address this problem,some recent works learn to infer future events based on historical eventbased temporal knowledge graphs.However,these methods do not comprehensively consider the latent patterns and influences behind historical events and concurrent events simultaneously.This paper proposes a new graph representation learning model,namely Recurrent Event Graph ATtention Network(RE-GAT),based on a novel historical and concurrent events attention-aware mechanism by modeling the event knowledge graph sequence recurrently.More specifically,our RE-GAT uses an attention-based historical events embedding module to encode past events,and employs an attention-based concurrent events embedding module to model the associations of events at the same timestamp.A translation-based decoder module and a learning objective are developed to optimize the embeddings of entities and relations.We evaluate our proposed method on four benchmark datasets.Extensive experimental results demonstrate the superiority of our RE-GAT model comparing to various base-lines,which proves that our method can more accurately predict what events are going to happen.

Bovine serum albumin:An efficient and green biocatalyst for the one-pot four-component synthesis of pyrano[2,3-c]pyrazoles

The use of biocatalysts is attracting an increasing amount of attention in chemical catalysis.Here,we have shown that bovine serum albumin（BSA）,a ubiquitous,inexpensive,non-enzymatic transport protein,can serve as an efficient,retrievable catalyst in the one-pot four-component reaction of aryl aldehydes,malononitrile,hydrazine hydrate,and ethyl acetoacetate for the synthesis of pyrano[2,3-c]pyrazoles under mild reaction conditions.The BSA biocatalyst also displayed a high catalytic affinity for acyclic/cyclic ketones to yield the corresponding pyrano[2,3-c]pyrazoles or their spirocyclic variants.The BSA could be used for at least five cycles without serious loss of catalytic activity.This novel,efficient protocol has the merits of high yield,operational simplicity,and a relatively benign environmental impact.Moreover,the method extends the promiscuity of BSA as a biocatalyst.

Heavy metal pollution and health risk in China

Following rapid social and economic development over the past several decades,pollution by heavy metals has been both serious and widespread in many areas of the world,including China.The situations of heavy metal pollution in China were reviewed,and the health risk and control policy of such pollution were also analyzed and discussed in present paper.

Transformation of single drop breakup from binary to ternary and multiple in turbulent jet flows

By releasing liquid drops in turbulent jet flows,we investigated the transformation of single drop breakup from binary to ternary and multiple.Silicone oil and deionized water were the dispersed phase and continuous phase,respectively.The probability of binary,ternary,and multiple breakup of oil drops in jet flows is a function of the jet Reynolds number.To address the underlying mechanisms of this transformation of drop breakup,we performed two-dimensional particle image velocimetry(PIV)experiments of single-phase jet flows.With the combination of drop breakup phenomenon and two-dimensional PIV results in a single-phase flow field,these transformation conditions can be estimated:the capillary number ranges from 0.17 to 0.27,and the Weber number ranges from 55 to 111.