In-situ electrochemical study on the eff ects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation

Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment.The results illustrated that increasing Fe(Ⅲ)concentrations led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of elemental sulfur.Reduction of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising temperatures.While,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall reaction.Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentrations,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.

Method of fabricating artificial rock specimens based on extrusion free forming(EFF)3D printing

Three-dimensional(3D)printing technology has been widely used to create artificial rock samples in rock mechanics.While 3D printing can create complex fractures,the material still lacks sufficient similarity to natural rock.Extrusion free forming(EFF)is a 3D printing technique that uses clay as the printing material and cures the specimens through high-temperature sintering.In this study,we attempted to use the EFF technology to fabricate artificial rock specimens.The results show the physico-mechanical properties of the specimens are significantly affected by the sintering temperature,while the nozzle diameter and layer thickness also have a certain impact.The specimens are primarily composed of SiO_(2),with mineral compositions similar to that of natural rocks.The density,uniaxial compressive strength(UCS),elastic modulus,and tensile strength of the printed specimens fall in the range of 1.65–2.54 g/cm3,16.46–50.49 MPa,2.17–13.35 GPa,and 0.82–17.18 MPa,respectively.It is capable of simulating different types of rocks,especially mudstone,sandstone,limestone,and gneiss.However,the simulation of hard rocks with UCS exceeding 50 MPa still requires validation.

中药山慈菇基原物种生态适宜性关键生态因子及区划研究

目的为山慈菇基原物种科学引种和选址扩种提供理论基础。方法通过查询多个数据库和实地调查,收集山慈菇基原物种在全国范围内的257个有效分布数据。综合海拔、温度、太阳辐射、降雨量和水汽压5个类别共68个生态因子,利用Maxent和ArcGIS对山慈菇基原物种的生态适宜性进行分析。结果分析得到影响山慈菇生态适宜性的关键生态因子主要是降雨量、太阳辐射以及海拔,不同基原物种间关键生态因子有显著差异。最适宜杜鹃兰、独蒜兰以及云南独蒜兰生长的潜在区域分别集中在台湾、华南地区以及云南四川相接一带。结论本研究进一步对其潜在分布区分别进行了生态适宜性等级划分,为山慈菇合理引种栽培及人工规范化扩种提供科学依据。

超薄ZnTi-LDH纳米片作为一种具有路易斯酸和布朗斯特酸的双功能光催化剂用于串联反应合成N-亚苄基苯胺

半导体光催化作为一种绿色可持续方法受到研究者的广泛关注.由于理论模型与实际催化剂存在较大差异,探究活性位点与光催化性能之间的关系一直是一个悬而未决的问题,需要寻找一种合适的材料深入了解该关系.超薄二维纳米材料因其活性位点占比较高,且活性位点种类相对简单而被认为是一种理想的模型.串联催化反应可以在单一体系中进行多步反应,避免了相对复杂的中间体分离和纯化,具有较大的经济和环保效益.在该过程中,独立的活性位点在不同的催化反应中起着重要的作用.目前已有一些关于光催化串联反应的研究报道,基于光催化过程,一般通过电子空穴分离效率或基于半导体价带理论来揭示,而活性位点与光催化性能之间的相互作用仍有待进一步研究.本文制备了两种不同厚度(1.4和4.0 nm)的超薄ZnTi-LDH纳米片用于光催化串联反应合成N-亚苄基苯胺,研究了该体系中的活性位点-催化性能的相互关系.X射线光电子能谱、红外光谱(FTIR)和电子自旋共振结果表明,减小ZnTi-LDH纳米片的厚度,可以暴露出更多的表面羟基和氧空位缺陷,形成配位不饱和Ti位点.紫外-可见光漫反射光谱和原位吸附FTIR光谱结果表明,在ZnTi-LDH纳米片上两种反应物(苯甲醇和硝基苯)能有效地化学吸附并活化.其中苯甲醇分子通过C-O···Ti的配位方式吸附并活化在配位不饱和Ti位点(L酸位点)上,而硝基苯分子以N-O···H-O的配位方式吸附并活化表面羟基的氢位点(B酸位点)上.在该体系中,光生空穴和光生电子能被有效利用,分别促进了苯甲醇选择性氧化为苯甲醛和硝基苯选择性还原为苯胺.阻抗和光电流实验结果表明,ZnTi-LDH纳米片厚度越薄,越有利于提高光生电子-空穴对的分离效率.由于其厚度的减小形成了氧空位,而氧空位作为电子的捕获中心,促进了光生电子-空穴对的分离.更薄的ZnTi-LDH纳米片具有更多的活性位点,不仅有利于反应物的活化,也有利于光生载流子的分离.因此,较薄的ZnTi-LDH纳米片实现了100%的高转化率和96%的高选择性.从分子水平上提出了该串联反应体系中分子活化协同光催化的机理.本文不仅为串联反应开发了具有独立活性位点的双功能催化剂,而且通过从分子水平上研究活性位点与催化性能之间的相互作用,对光催化机理提供了深入的认识.

Microstructure characteristics and mechanical properties of Al/Mg joints manufactured by magnetic pulse welding

The effective connection of 1050 Al and AZ31 Mg was realized by magnetic pulse welding.The maximum tensile-shear force of the dissimilar Al/Mg metal lap joint reached 97%of that of the 1050 Al alloy base material by optimizing the process parameters.The microstructure of dissimilar Al/Mg welded joints was analysed by Scanning Electron Microscope(SEM),Energy Dispersive Spectrometer(EDS)and Electron Backscattered Diffraction(EBSD).The results show that the key to obtaining high shear strength of Al/Mg dissimilar metal joints is mainly due to the following two reasons.On the one hand,grain refinement and element interdiffusion occur at the interface.On the other hand,no intermetallic compounds are formed at the interface.

利用煤系硅藻土制备磁性油污吸附剂的实验研究

本文以实现先锋高有机质含量硅藻土废弃资源合理利用,提高先锋煤矿区的矿产资源综合利用率的目标出发,以云南先锋褐煤共生的硅藻土尾矿为载体,利用化学共沉淀法,制备磁性硅藻土复合材料。将磁性材料的易分性和硅藻土的吸附性有机结合起来,应用于海洋原油清污处理的实验研究。通过电子扫描显微镜(SEM)、X射线衍射分析(XRD)和X射线荧光分析(XRF)等表征表明,由煤系硅藻土制备的磁性硅藻土是理想的原油清污材料。磁性纳米颗粒:硅藻土为1:5的磁性硅藻土清理油污能力达到91.6%。本文开展的实验研究有利于非金属矿产资源的综合利用,减少原油污染给环境带来的危害。

养颜青蛾丸对D-半乳糖诱导的小鼠衰老皮肤氧化应激及MMP-1、MMP-3表达的影响

目的观察养颜青蛾丸对D-半乳糖诱导的小鼠衰老皮肤氧化应激及MMP-1、MMP-3表达的影响。方法小鼠颈背部皮下注射D-半乳糖制备小鼠皮肤衰老模型。造模过程中,实验组同时每天给予养颜青娥丸低、中、高剂量组等体积药物灌胃。连续给药42 d后,测定小鼠血清SOD、MDA和小鼠皮肤组织上清液中SOD、MDA含量、皮肤含水量、皮肤胶原蛋白含量,Western blot检测皮肤组织中MMP-1、MMP-3蛋白表达。结果养颜青娥丸中、高剂量组小鼠皮肤含水量、皮肤胶原蛋白Ⅰ和Ⅲ含量、血清和皮肤组织SOD含量均显著高于模型组(P<0.05)。养颜青娥丸中、高剂量组小鼠血清和皮肤组织MDA含量、MMP-1、MMP-3蛋白表达水平均显著低于模型组(P<0.05)。养颜青娥丸中、高剂量组小鼠皮肤含水量,皮肤胶原蛋白Ⅰ和Ⅲ含量,血清和皮肤组织SOD含量,血清和皮肤组织MDA含量,MMP-1、MMP-3蛋白表达水平,两组间比较,差异有统计学意义(P<0.05)。结论养颜青娥丸通过调节氧化应激损伤,下调皮肤基质金属蛋白酶MMP-1、MMP-3的表达,继而提高皮肤含水量,增加皮肤胶原蛋白Ⅰ和Ⅲ含量,从而延缓D-半乳糖诱导的小鼠皮肤衰老。

Two-dimensional MOF/MOF derivative arrays on nickel foam as efficient bifunctional coupled oxygen electrodes

Oxygen electrocatalysis,exemplified by the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),is central to energy storage and conversion technologies such as fuel cells,metal-air batteries,and water electrolysis.However,highly effective and inexpensive earth-abundant materials are sought after to replace the noble metal-based electrocatalysts currently in use.Recently,metal-organic frameworks(MOFs)and carbon-based MOF derivatives have attracted considerable attention as efficient catalysts due to their exceedingly tunable morphologies,structures,compositions,and functionalization.Here,we report two-dimensional(2D)MOF/MOF derivative coupled arrays on nickel foam as binder-free bifunctional ORR/OER catalysts with enhanced electrocatalytic activity and stability.Their remarkable electrochemical properties are primarily attributed to fully exposed active sites and facilitated charge-transfer kinetics.The coupled and hierarchical nanosheet arrays produced via our growth-pyrolysis-regrowth strategy offer promise in the development of highly active electrodes for energy-related electrochemical devices.

R2R3-MYB transcription factors, StmiR858 and sucrose mediate potato flavonol biosynthesis

Flavonols and other phenylpropanoids protect plants from biotic and abiotic stress and are dietarily desirable because of their health-promoting properties.The ability to develop new potatoes(Solanum tuberosum)with optimal types and amounts of phenylpropanoids is limited by lack of knowledge about the regulatory mechanisms.Exogenous sucrose increased flavonols,whereas overexpression of the MYB StAN1 induced sucrolytic gene expression.Heterologous StAN1 protein bound promoter fragments from sucrolytic genes(SUSY1 and INV1).Two additional MYBs and one microRNA were identified that regulated potato flavonols.Overexpression analysis showed MYB12A and C increased amounts of flavonols and other phenylpropanoids.Endogenous flavonol amounts in light-exposed organs were much higher those in the dark.Expression levels of StMYB12A and C were high in flowers but low in tubers.Transient overexpression of miR858 altered potato flavonol metabolism.Endogenous StmiR858 expression was much lower in flowers than leaves and correlated with flavonol amounts in these organs.Collectively,these findings support the hypothesis that sucrose,MYBs,and miRNA control potato phenylpropanoid metabolism in a finely tuned manner that includes a feedback loop between sucrose and StAN1.These findings will aid in the development of potatoes with phenylpropanoid profiles optimized for crop performance and human health.

在无机化学教学中培养学生的创新思维

根据无机化学授课对象的特点,结合无机化学教学心得,分别以水的电化学稳定窗口、配位化学的发展史及铝离子浓度的测定为例,讲述了科学研究、化学史、实践与教学内容相结合对提高教学效果、培养学生创新思维的作用。

Spatio-temporal variation of ecosystem service values adjusted by vegetation cover:a case study of Wuyishan National Park Pilot,China

Ecosystem service values(ESV)are strongly influenced by the vegetation cover,which is heterogeneous across different vegetation types.We develop a dynamic evaluation model of ESV for Wuyishan National Park Pilot adjusted by the rate of inflation and the fractional vegetation cover,which is calculated by an enhanced vegetation index from 2000 to 2018.The spatio-temporal variation of vegetation was also examined.The results demonstrated that:(1)the unit area of ecosystem service values adjusted by vegetation cover(ESVVC)shows a gradient of forest>tea plantation>grassland>cropland,and the major ecosystem services provided by forests include soil formation and conservation,climate regulation,and biodiversity maintenance;(2)the ESV_(VC) increased to 2.1 billion yuan(The reference rate announced by the People’s Bank of China is the US dollar to 6.42 Yuan per dollar.)from 2000 to 2018.Higher and lower ESV_(VC) are predominant in the northwest and southeast region,respectively.In addition,changes of ecological protection structures and human disturbances negatively affected vegetation cover,leading to a decreased ESVVC from 2000 to 2005 in the Jiuqu Stream Ecological Protection Area and the Wuyishan National Scenic Spot.The implementation of ecological protection policies from 2010 to 2018 enhanced the ESV_(VC) in the study area;and,(3)the ESVVC is highest in the southeast and 25°–35°area with altitudes of 800–1000 m.Our model can provide timely and helpful information of changes in ESV for use in ecological corridor design and ecological security monitoring.

蜈蚣药材商品规格等级标准研究

[目的]理清蜈蚣药材流通现状,制定蜈蚣药材商品规格等级标准,用于指导规范蜈蚣药材流通。[方法]在本草考证的基础上,进行市场流通现状调研,确定其与蜈蚣主要产地流通现状之间的联系。[结果]蜈蚣药材存在“蜈蚣条”和“蜈蚣皮”2种规格,根据长度将“蜈蚣条”划分为3个不同等级,“蜈蚣皮”为统货。[结论]新的蜈蚣药材规格等级标准的制定对于指导市场蜈蚣药材流通具有重要意义,也为蜈蚣药材的化学成分和分子机制研究奠定基础。

Upgrading the Fermentation Process of Zhejiang Rosy Vinegar by Purebred Microorganisms

Purebred microorganisms were employed to upgrade the fermentation process of Zhejiang rosy vinegar. The fermentation cycle was greatly shorten from 5 months to 72 d. The transformation rate of raw materials was increased from 1:4.5 in the traditional fermentation to 1:5 or more in the upgraded fermentation. The content of organic acids in the traditional vinegar (TRV), the upgraded vinegar (UPV) and the submerged fermentation vinegar (SFV) were also investigated by HPLC. No significant difference was found regarding the proportion of phenylethanol to the total volatile components in UPV (7.47% ± 0.00324%) and TRV (7.23% ± 0.00329%), but it was significantly higher than that in SFV (2.26% ± 0.00143%). This study provides deep insight into upgrading the fermentation process of Zhejiang rosy vinegar by purebred microorganisms.

Sudden deafness as a prodrome of cerebellar artery infarction:Three case reports

BACKGROUND To summarize the clinical characteristics of acute cerebral infarction(ACI)in patients with sudden deafness(SD)as the first symptom,improve the awareness of the disease,and help diagnosis and treatment.CASE SUMMARY From 2019 to 2020,three patients with ACI with SD as the first symptom were admitted to our hospital.Pure tone audiometry,head magnetic resonance imaging(MRI),vertebral artery and carotid artery B-ultrasound,head and neck computed tomography angiography,and other examinations were performed.Following the treatment of SD,hearing and dizziness were not significantly improved.Then,the patients developed symptoms of related cranial nerve injury,and brain MRI showed cerebral infarction in the cerebellopontine angle area.All three cases were transferred to the neurology department for relevant conservative treatment.CONCLUSION Patients with ACI with SD as the first symptom usually attend the otolaryngology clinic.Here a diagnosis of SD,which is based on an audiological examination,is made and the corresponding treatment is administered.To reduce the misdiagnosis of this disease,close attention should be paid to the changes in the patient's clinical symptoms and related auxiliary examinations should be performed,such as brain MRI and cerebrovascular imaging.Otolaryngologists should pay attention to the type and severity of hearing loss,the accompanying symptoms,age,high-risk factors for cerebral infarction,and related cranial nerve symptoms in patients with SD.If the patient's early brain MRI does not show abnormalities,monitoring remains essential.The head MRI should be analyzed quickly based on the changes in the symptoms of the patient,to make an accurate diagnosis and provide the timely and correct treatment for the patients.

Catalytic role of assembled Ce Lewis acid sites over ceria for electrocatalytic conversion of dinitrogen to ammonia

CeO_(2)-based catalysts are emerging as novel candidates for catalyzing nitrogen reduction reaction(NRR).However, despite the increasing amount of experimental and theoretical research, the design of more efficient ceria catalysts for NRR remains a challenge due to the poor knowledge of the catalytic mechanism, particularly the nature of the active sites and how they catalyze NRR. Here, using first-principle calculations, we investigated the NRR catalysis process involving adjacent Ce Lewis acid clusters formed on(111),(110), and(100) facets of CeO_(2) as active sites. Our results revealed that the assembled structures of the Ce Lewis acid as active centers after the oxygen vacancies(Ovs) were opened. The exposed Ce sites on CeO_(2)(111), CeO_(2)(110), and CeO_(2)(100) can cause N_(2) to be adsorbed in a ‘‘lying-down" manner, which facilitates the N2 activation and thus leads to much higher NRR activity. Furthermore, from the perspective of electronic structure, we establish two useful descriptors for assessing the NRR activity on ceria with Ovs:The N–N bond strength of the adsorbed N_(2) and the adsorption energy of the *N_(2)H intermediate. This work thus provides direct guidance for the design of more-effective oxide catalysts without the use of scarce metals.

Halogen-Driven Bandgap Opening in Graphdiyne for Overall Photocatalytic Water Splitting

In this work,we studied the electronic band structure of the halogen(F,Cl,and Br)functionalized graphdiynes(GDYs)by using hybrid density functional theory.The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases.It is also found that the position of the valence band maximum(VBM)is influenced by the electronegativity of halogen atoms.The higher the electronegativity,the deeper the VBM of the GDYs modified by the same number of halogen atoms.Importantly,our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms.The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water.Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models.This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.

阴地蕨属药用植物matK基因编码区全序列测定及编码产物研究

以阴地蕨属(Botrychium)5种药用植物的matK基因为对象,分析matK基因编码区全序列和其编码产物MATK蛋白的氨基酸序列特征,并比较他们在用于阴地蕨属药用植物系统发育关系研究中的差异。结果显示,阴地蕨属5种植物matK基因全长为1500~1503 bp,共有153个变异位点,其编码产物均为不稳定的亲水性蛋白,无跨膜结构,二级结构以α-螺旋和无规则卷曲为主。系统发育分析结果表明,基于matK基因序列的系统发育分析更适合于阴地蕨属种间亲缘关系的鉴定,说明matK基因在阴地蕨属植物的鉴定中具有一定的应用价值。

Development of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus

We developed a set of in-situ Micro-Raman spectroscopy system for autoclave experimental apparatus because of the scientific significance of in-situ Micro-Raman spectroscopy system under the high-pressure hydrothermal condition.We used this system to measure the Raman spectrum of water-fluid and quartz crystal at the temperature ranging from 125 to 420℃.The signal-tonoise ratio of the Raman signal is good.

Assessing Density Functionals for Describing Methane Dissociative Chemisorption on Pt(110)-(2×1)Surface

In this work,we explore the suitability of several density functionals with the generalized gradient approximation(GGA)and beyond for describing the dissociative chemisorption of methane on the reconstructed Pt(110)-(2×1)surface.The bulk and surface structures of the metal,methane adsorption energy,and dissociation barrier are used to assess the functionals.A van der Waals corrected GGA functional(optPBE-vdW)and a metaGGA functional with van der Waals correction(MS PBEl-rVV10)are selected for ab initio molecular dynamics calculations of the sticking probability.Our results suggest that the use of these two functionals may lead to a better agreement with existing experimental results,thus serving as a good starting point for future development of reliable machine-learned potential energy surfaces for the dissociation of methane on the Pt(110)-(2×1)surface.

Research on the Development of 5G Wireless Communication in the Industrial Field

The development of science and technology is the key to changing human life and promoting social and economic development.As a product of technological development,the widespread application of communication technology has brought a brand new“dawn”to the development of human society.5G wireless communication technology is an advanced wireless communication technology that has recently developed.With the advantages of low energy consumption and high network speed,5G technology has shown very bright development prospects in various fields today.Government,operators and equipment providers are actively promoting and deploying 5G technology,and all links in the industry chain are mature.It is expected that the future market size will reach 17 trillion,especially in today’s industrial field,the application of 5G technology will further enhance work efficiency,ensure work quality,and promote good development in the industrial field.Based on this,this paper will study the development of 5G wireless technology in the industrial field,so as to provide corresponding reference for the good application of 5G technology in the industrial field.