Failure evolution and disaster prediction of rock under uniaxial compression based on non-extensive statistical analysis of electric potential

Rock failure can cause serious geological disasters,and the non-extensive statistical features of electric potential(EP)are expected to provide valuable information for disaster prediction.In this paper,the uniaxial compression experiments with EP monitoring were carried out on fine sandstone,marble and granite samples under four displacement rates.The Tsallis entropy q value of EPs is used to analyze the selforganization evolution of rock failure.Then the influence of displacement rate and rock type on q value are explored by mineral structure and fracture modes.A self-organized critical prediction method with q value is proposed.The results show that the probability density function(PDF)of EPs follows the q-Gaussian distribution.The displacement rate is positively correlated with q value.With the displacement rate increasing,the fracture mode changes,the damage degree intensifies,and the microcrack network becomes denser.The influence of rock type on q value is related to the burst intensity of energy release and the crack fracture mode.The q value of EPs can be used as an effective prediction index for rock failure like b value of acoustic emission(AE).The results provide useful reference and method for the monitoring and early warning of geological disasters.

Pressure stimulated current in progressive failure process of combined coal-rock under uniaxial compression:Response and mechanism

Effective monitoring of the structural health of combined coal-rock under complex geological conditions by pressure stimulated currents(PSCs)has great potential for the understanding of dynamic disasters in underground engineering.To reveal the effect of this way,the uniaxial compression experiments with PSC monitoring were conducted on three types of coal-rock combination samples with different strength combinations.The mechanism explanation of PSCs are investigated by resistivity test,atomic force microscopy(AFM)and computed tomography(CT)methods,and a PSC flow model based on progressive failure process is proposed.The influence of strength combinations on PSCs in the progressive failure process are emphasized.The results show the PSC responses between rock part,coal part and the two components are different,which are affected by multi-scale fracture characteristics and electrical properties.As the rock strength decreases,the progressive failure process changes obviously with the influence range of interface constraint effect decreasing,resulting in the different responses of PSC strength and direction in different parts to fracture behaviors.The PSC flow model is initially validated by the relationship between the accumulated charges of different parts.The results are expected to provide a new reference and method for mining design and roadway quality assessment.

Measurement and correlation of solubility of 9-fluorenone in 11 pure organic solvents from T = 283.15 to 323.15 K

In this work, the solubility data of 9-fluorenone in 11 pure solvents(methanol, ethanol, n-propanol, isopropanol, n-butanol, iso-butanol, acetonitrile, ethyl formate, ethyl acetate, dimethyl sulfoxide, n-hexane)were measured by the gravimetric method from 278.15 K to 318.15 K under atmospheric pressure. The results showed that the solubility of 9-fluorenone in all tested solvents increased with the raised temperature. The solubility data were correlated by the modified Apelblat equation, λh model and NRTL(nonradom two fluid) model. The average relative deviation(ARD) correlated by three thermodynamic models in different solvents was all below 5%, which indicated that the three thermodynamic models fit the solubility data well. Furthermore, the mixing thermodynamic properties of 9-fluorenone in pure solvent systems were calculated via NRTL model. The results indicated the dissolution process of 9-fluorenone is spontaneous and entropically favorable. The solubility and the mixing thermodynamic properties provided in this paper would play an important role in industrial manufacture and follow-up operation of 9-fluorenone.

粗糙脉孢菌7种子囊型归类教学探究

遗传分析是本科遗传学教学的重要内容,四分子分析是真菌类遗传分析的独特方式,其中的粗糙脉孢菌顺序四分子分析不仅可以研究基因与着丝粒间的重组、基因间的重组,而且还可以精细研究同源染色体非姊妹染色单体之间的交换形式,是深入理解交换重组分子机制的重要遗传学研究材料。对此,教材中已有详尽的介绍。美中不足的是,中外教科书和相关专业期刊中缺乏对顺序四分子两基因连锁分析中7种基本子囊型归纳方法的具体介绍,令相关内容的学习留下疑惑。本文从顺序四分子两基因连锁遗传分析过程中涉及的3种四分子类型(PD、NPD和T)与两基因4种分离时期组合(ⅠⅠ,ⅡⅡ,ⅠⅡ,ⅡⅠ)的相互关系入手,设计表格,直观展现了二者的12种可能组合结果(3×4=12),并应用直观的对错符号(√、×),同时结合表后的3项分析,排除了其中的5种组合形式,最终归纳得到7种基本子囊型。本文提供了7种基本子囊型具体的归纳分析方法,解决了相关教学内容的论述不足问题,以期为真菌类顺序四分子遗传分析的教学提供帮助。

三阴性乳腺癌组织亲嗜性病毒整合位点1和核转运蛋白基因2的表达及与临床病理特征和预后的关系

目的探讨亲嗜性病毒整合位点1(EVI1)、核转运蛋白基因2(KPNA2)在三阴性乳腺癌(TNBC)的表达,分析EVI1、KPNA2表达与临床病理特征及预后的关系。方法选取2012年1月—2015年1月中国人民解放军联勤保障部队第983医院收集的73例TNBC患者手术切除的癌组织、癌旁组织及70例正常乳腺组织(对照组)的石蜡标本,采用免疫组织化学法检测EVI1、KPNA2的阳性表达。收集相关临床病理资料,分析EVI1、KPNA2表达与TNBC患者临床病理特征的关系,采用Kaplan-Meier生存曲线分析不同EVI1、KPNA2表达下TNBC患者无进展生存时间(PFS)及总生存时间(OS)差异。结果癌组织、癌旁组织和对照组EVI1、KPNA2阳性表达率比较,差异有统计学意义(P<0.05),TNBC癌组织中EVI1、KPNA2阳性表达率高于癌旁组织和对照组(P<0.05),癌旁组织和对照组EVI-1、KPNA2阳性表达率比较,差异无统计学意义(P>0.05)。不同组织学分级、淋巴结、Ki-67表达、脉管内癌栓TNBC患者的EVI1阳性表达率比较,差异有统计学意义(P<0.05),淋巴结是否转移的TNBC患者的KPNA2阳性表达率比较,差异有统计学意义(P<0.05)。Kaplan-Meier生存分析结果显示EVI1阳性表达、KPNA2阳性表达患者PFS、OS生存率均低于EVI1阴性表达、KPNA2阴性表达患者(P<0.05)。结论EVI1、KPNA2阳性表达与TNBC患者肿瘤恶性侵袭行为和预后不良有关,评价EVI1、KPNA2表达可为TNBC患者预后预测提供一定的依据。

Preparation and evaluation of α-Al2O3 supported lithium ion sieve membranes for Li^+ extraction

Spinel lithium manganese oxide ion-sieves have been considered the most promising adsorbents to extract Li^+ from brines and sea water.Here,we report a lithium ion-sieve which was successfully loaded onto tubular α-Al2 O3 ceramic substrates by dipping crystallization and post-calcination method.The lithium manganese oxide Li4 Mn5 O(12)was first synthesized onto tubular α-Al2 O3 ceramic substrates as the ion-sieve precursor(i.e.L-AA),and the corresponding lithium ion-sieve(i.e.H-AA) was obtained after acid pickling.The chemical and morphological properties of the ion-sieve were confirmed by X-ray diffraction(XRD) and scanning electron microscopy(SEM).Both L-AA and H-AA showed characteristic peaks of α-Al2 O3 and cubic phase Li4 Mn5 O(12) and the peaks representing cubic phase could still exist after pickling.The lithium manganese oxide Li4 Mn5 O(12) could be uniformly loaded not only on the surface of α-Al2 O3 ubstrates but also inside the pores.Moreover,we found that the equilibrium adsorption capacity of H-AA was 22.9 mg·g^-1.After 12 h adsorption,the adsorption balance was reached.After 5 cycles of adsorption,the adsorption capacity of H-AA was 60.88% of the initial adsorption capacity.The process of H-AA adsorption for Li^+correlated with pseudo-second order kinetic model and Langmuir model.Adsorption thermodynamic parameters regarding enthalpy(△N), Gibbs free energy(△G) and entropy(AS) were calculated.For the dynamic adsorptiondesorption process of H-AA,the H-AA exhibited excellent adsorption performance to Li^+ with the Li^+ dynamic adsorption capacity of 9.74 mg·g^-1 and the Mn^2+dissolution loss rate of 0.99%.After 3 dynamic adsorption-desorption cycles,80% of the initial dynamic adsorption capacity was still kept.

Impact of product heterogeneity and soft budget constraint on excess capacity in Chinese energy industry based on the duopoly model

Chinese energy industries are facing serious problems such as excess capacity,homogeneous product,and soft budget constraint.This paper provides a duopoly model to investigate the influence of heterogeneity and soft budget constraint on production capacity decision and internal action mechanism,respectively,under Cournot and Bertrand competitions,which reveals the formation mechanism of excess capacity.We conclude that excess capacity would exist when the products are not wholly heterogeneous under Cournot competition,and the higher level of the soft budget constraint or the more homogeneous the products are,the worse the excess capacity will be.The insufficient capacity would exist provided that products are not wholly heterogeneous under Bertrand competition,and the higher level of soft budget constraint or the more homogeneous the products are,the more insufficient capacity will be.Both soft budget constraint and product heterogeneity mutually affect to decision-making of capacity and output.

Isothermal Adsorption and Desorption Properties of Marine Shales on Longmaxi Shale in South China

The investigation of adsorption and desorption properties of shale are important for estimating reserves and exploitation. The shale samples used in this paper were from the marine shale on Longmaxi shale in Sichuan and Hubei province, China. A series of analyses, such as organic carbon content test, vitrinite reflectance test, rock pyrolysis, X-ray diffraction, and N2/CO2 adsorption were performed. Gravimetric method with magnetic suspension balance was used to conduct isothermal adsorption and desorption experiments. The Langmuir, Freundlich, Langmuir-Freundlich, D-R, semi-pore, and Tothequations were used to fit the isothermal adsorption and desorption curves. And adsorption potential theory was used to explain the adsorption and desorption process. According to the results, the shale samples have a high level of organic carbon content with the same organic matter type II1 and high degree of maturation. The volume of adsorption increases rapidly and slows down to stable with the pressure increasing. Desorption is the inverse process of adsorption and 10 MPa - 0.5 MPa is the main period of shale gas desorption. The fitting results show that three-parameter isotherm equations are better than the two-parameter ones. The adsorption temperature has a great influence on adsorption volume, little effect on potential energy. Adsorption potential varies under different TOC to affect adsorption properties. Moreover, a large adsorption potential means that the gas molecule is easy to adsorb but difficult to desorb.

Actin-depolymerizing factors 8 and 11 promote root hair elongation at high pH

A root hair is a polarly elongated single-celled structure that derives from a root epidermal cell and func-tions in uptake of water and nutrients from the surrounding environment.Previous reports have demon-strated that short periods of high pH inhibit root hair extension;but the effects of long-term high-pH treat-ment on root hair growth are still unclear.Here,we report that the duration of root hair elongation is signicantly prolonged with increasing external pH,which counteracts the effect of decreasing root hair elongation rate and ultimately produces longer root hairs,whereas loss of actin-depolymerizing factor 8 and 11(ADF8/11)function causes shortening of root hair length at high pH(pH 7.4).Accumulation of ADF8/11 at the tips of root hairs is inhibited by high pH,and increasing environmental pH affects the actinlament(F-actin)meshwork at the root hair tip.At high pH,the tip-focused F-actin meshwork is absent in root hairs of the adf8/11 mutant,actinlaments are disordered at the adf8/11 root hair tips,and actin turn-over is attenuated.Secretory and recycling vesicles do not aggregate in the apical region of adf8/11 root hairs at high pH.Together,our results suggest that,under long-term exposure to high extracellular pH,ADF8/11 may establish and maintain the tip-focused F-actin meshwork to regulate polar trafcking of secretory/recycling vesicles at the root hair tips,thereby promoting root hair elongation.

Fine particulate matter and cardiorespiratory health in China:A systematic review and meta-analysis of epidemiological studies

This review aimed to systematically summarize the epidemiological literature on the cardiorespiratory effects of PM_(2.5)published during the 13^(th) Five-Year Plan period(2016-2020)in China.Original articles published between January 1,2016 and June 30,2021 were searched in PubMed,Web of Science,the China National Knowledge Internet Database and Wanfang Database.Random-or fixed-effects models were used to pool effect estimates where appropriate.Of 8558 records identified,145 met the full eligibility criteria.A 10μg/m^(3) increase in short-term PM_(2.5)exposure was significantly associated with increases of 0.70%,0.86%,0.38%and 0.96%in cardiovascular mortality,respiratory mortality,cardiovascular morbidity,and respiratory morbidity,respectively.The specific diseases with significant associations included stroke,ischemic heart disease,heart failure,arrhythmia,chronic obstructive pulmonary disease,pneumonia and allergic rhinitis.The pooled estimates per 10μg/m^(3) increase in long-term PM_(2.5)exposure were 15.1%,11.9%and 21.0%increases in cardiovascular,stroke and lung cancer mortality,and 17.4%,11.0%and 4.88%increases in cardiovascular,hypertension and lung cancer incidence respectively.Adverse changes in blood pressure,heart rate variability,systemic infiammation,blood lipids,lung function and airway infiammation were observed for either short-term or long-term PM_(2.5)exposure,or both.Collectively,we summarized representative exposure-response relationships between short-and long-term PM_(2.5)exposure and a wide range of cardiorespiratory outcomes applicable to China.The magnitudes of estimates were generally smaller in short-term associations and comparable in long-term associations compared with those in developed countries.Ourfindings are helpful for future standard revisions and policy formulation.There are still some notable gaps that merit further investigation in China.

SEC1A and SEC6 synergistically regulate pollen tube polar growth

Pollen tube polar growth is a key physiological activity for angiosperms to complete double fertilization, which is highly dependent on the transport of polar substances mediated by secretory vesicles.The exocyst and Sec1/Munc18(SM) proteins are involved in the regulation of the tethering and fusion of vesicles and plasma membranes, but the molecular mechanism by which they regulate pollen tube polar growth is still unclear. In this study, we found that loss of function of SEC1A, a member of the SM protein family in Arabidopsis thaliana, resulted in reducing pollen tube growth and a significant increase in pollen tube width. SEC1A was diffusely distributed in the pollen tube cytoplasm, and was more concentrated at the tip of the pollen tube. Through coimmunoprecipitation-mass spectrometry screening,protein interaction analysis and in vivo microscopy,we found that SEC1A interacted with the exocyst subunit SEC6, and they mutually affected the distribution and secretion rate at the tip of the pollen tube. Meanwhile, the functional loss of SEC1A and SEC6 significantly affected the distribution of the SNARE(soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complex member SYP125 at the tip of the pollen tube, and led to the disorder of pollen tube cell wall components. Genetic analysis revealed that the pollen tube-related phenotype of the sec1a sec6 double mutant was significantly enhanced compared with their respective single mutants. Therefore, we speculated that SEC1A and SEC6 cooperatively regulate the fusion of secretory vesicles and plasma membranes in pollen tubes, thereby affecting the length and the width of pollen tubes.

Viologens-based redox mediators with tunable HOMO–LUMO energy gap for highly effective hydrogen peroxide electrosynthesis

In comparison with the developing nano-carbon catalysts,some small organic molecules are also emerging as catalysts with typical features,however,their working mechanism is still unclear.Here,we synthesized a series of viologen-based heterogeneous catalysts with the same molecular skeleton but different substituent groups through anion exchange engineering.These viologen-based molecules were used as a model catalyst to investigate the underlying structure–function relationship for small molecules-based H_(2)O_(2) electrosynthesis.Differing from the commonly reported carbon-based electrocatalysts,viologens can produce H_(2)O_(2) in a synergistic manner,which means that viologens can not only directly catalyze oxygen reduction but also serve as a redox mediator.We found that the ring current and H_(2)O_(2) selectivity of viologens deliver an increasing trend with the increase of the alkyl chain length of alkyl-substituted viologens and further increase when using benzyl as the substituent group.As a result,a benzyl-substituted viologen(BV)delivers the best electrocatalytic performance among the samples,including the highest H_(2)O_(2) selectivity of 96.9%at 0.6 V and the largest ring current density of about 13.6 mA·mmol-1.Furthermore,density functional theory(DFT)calculations disclose that the carbon atoms bonded with positively charged N are the active sites and the small highest occupied molecular orbital(HOMO)–lowest unoccupied molecular orbital(LUMO)energy gap of BV is beneficial to the synergistic mechanism for H_(2)O_(2) production.This work sheds new insight into the efficient H_(2)O_(2) production in a synergistic manner for small molecules-based electrocatalysts.

Expanding the potential of biosensors:a review on organic field effect transistor(OFET)and organic electrochemical transistor(OECT)biosensors

Organic electronics have gained significant attention in the field of biosensors owing to their immense potential for economical,lightweight,and adaptable sensing devices.This review explores the potential of organic electronics-based biosensors as a revolutionary technology for biosensing applications.The focus is on two types of organic biosensors:organic field effect transistor(OFET)and organic electrochemical transistor(OECT)biosensors.OFET biosensors have found extensive application in glucose,DNA,enzyme,ion,and gas sensing applications,but suffer from limitations related to low sensitivity and selectivity.On the other hand,OECT biosensors have shown superior performance in sensitivity,selectivity,and signal-to-noise ratio,owing to their unique mechanism of operation,which involves the modulation of electrolyte concentration to regulate the conductivity of the active layer.Recent advancements in OECT biosensors have demonstrated their potential for biomedical and environmental sensing,including the detection of neurotransmitters,bacteria,and heavy metals.Overall,the future directions of OFET and OECT biosensors involve overcoming these challenges and developing advanced devices with improved sensitivity,selectivity,reproducibility,and stability.The potential applications span diverse fields including human health,food analysis,and environment monitoring.Continued research and development in organic biosensors hold great promise for significant advancements in sensing technology,opening up new possibilities for biomedical and environmental applications.

Atomic cobalt anchored on covalent triazine frameworks with ultra-high performance towards oxygen reduction reaction

Single cobalt atom is promising non-precious metal catalyst instead of Pt in the oxygen reduction reaction(ORR).However,it is still a great challenge to develop a costeffective,ultrastable and efficent single-atom cobalt catalyst for ORR,requiring efficient fabrication strategies and robust support to stabilize the single cobalt atom.Here,we prepared a highly active and stable atomically isolated cobalt catalyst via covalent triazine framework(CTF)support with Ketjen Black(KB)hybridization in scale.The prepared single Co catalyst(Co-CTF/KB)possesses high metal loading over 4 wt%and shows superior ORR performance with a half-wave potential(E1/2)of 0.830 V and a limiting current density of 6.14 mA cm-2 as well as high tolerance of methanol in an alkaline medium,which outperforms commercial Pt/C and most non-precious-metal catalysts reported to date.Benefiting from strong stabilization of Co atoms on CTF,Co-CTF/KB shows outstanding stability with only 5 mV negative shifts after 10,000 cycles.Moreover,it also displays high catalytic activity for oxygen evolution reaction(OER),suggesting it is an efficient ORR/OER bifunctional catalyst.The present work provides a facile strategy for preparing single-atom catalysts in bulk quantity and contributes to development of catalysts for electrochemical conversion and storage devices.

Cascading V_(2)O_(3)/N-doped carbon hybrid nanosheets as high-performance cathode materials for aqueous zinc-ion batteries

In recent years, especially when there is increasing concern about the safety issue of lithium-ion batteries (LIBs), aqueous Zn-ion batteries (ZIBs) have been getting a lot of attention because of their cost-effectiveness, materials abundance, high safety, and ecological friendliness. Their working voltage and specific capacity are mainly determined by their cathode materials. Vanadium oxides are promising cathode materials for aqueous ZIBs owing to their low cost, abundant resources, and multivalence. However, vanadium oxide cathodes still suffer from unsatisfactory capacity, poor stability, and low electrical conductivity. In this work, cascading V_(2)O_(3)/nitrogen doped carbon (V_(2)O_(3)/NC) hybrid nanosheets are prepared for high-performance aqueous ZIBs by pyrolyzing pentyl viologen dibromide (PV) intercalated V_(2)O5 nanosheets. The unique structure features of V_(2)O_(3)/NC nanosheets, including thin sheet-like morphology, small crystalline V_(2)O_(3) nanoparticles, and conductive NC layers, endow V_(2)O_(3)/NC with superior performance compared to most of the reported vanadium oxide cathode materials for aqueous ZIBs. The V_(2)O_(3)/NC cathode exhibits the discharge capacity of 405 mAh/g at 0.5 A/g, excellent rate capability (159 mAh/g at 20 A/g), and outstanding cycling stability with 90% capacity retention over 4000 cycles at 20 A/g.

Rational design of viologen redox additives for high-performance supercapacitors with organic electrolytes

Introducing redox species into the electrolytes of traditional electric double layer capacitors(EDLCs)is an efficient strategy to enhance their energy density owing to Faradic reactions.However,few studies have elucidated the effect of the molecular structures of organic redox species on the performance of relative supercapacitors,which is important in the development of redox additives for super-capacitors.In this context,we synthesized several viologens and used them as new organic redox additives for super-capacitors with organic electrolytes.The detailed experimental analysis and theoretical calculation results show that the electrochemical performance of viologens relies heavily on their side chains and conjugated cores.Specifically,the side chains of the viologens affect their electronic structures and are consistent with behaviours between the molecules and the electrode pores due to the size effect,thus influencing their specific capacities.In addition,a larger conjugated aromatic core endows viologens with a smaller band gap and a higher degree of electron delocalization,resulting in better rate performance and cycling stability.Consequently,aπ-conjugated viologen derivative is selected as a favourable additive and enables an EDLC-type supercapacitor to exhibit a high energy density(34.0 W h kg^−1 at 856 W kg^−1)and good cycling performance.

Study of CH_(4)and CO_(2)competitive adsorption on shale in Yibin,Sichuan Province of China

Shale gas is an unconventional gas source with substantial development potential.In this study,Longmaxi Formation shale from the Silurian system in Yibin,Sichuan Province was collected for characterizing total organic carbon(TOC),clay mineral content,and other reservoir properties.The pore structure of shale was analyzed by field-emission scanning electron microscopy and low-temperature N_(2) adsorption–desorption method.Isothermal adsorption experiments for CH_(4)and CO_(2)mixtures in shale samples were performed.The second Virial coefficient was used to calculate for the compressibility factor of the gas mixture.The influencing factors of gas adsorption capacity of shale were analyzed.Finally,the CH_(4)and CO_(2)adsorption capacities and selection of shale samples were investigated.Under low pressure,the total gas mixture capacity of shale samples was positively correlated with pressure.When the pressure increased to a certain extent,the growth trend of gas mixture adsorption capacity of shale samples decreased.The mixed gas adsorption volume is high at 50℃ for all the proportion.Given the same temperature and pressure,the CO_(2)adsorption of shale samples is higher than the CH_(4)adsorption.In competitive adsorption,shale prefers to adsorb CO_(2).Therefore,CO_(2)is easier to be adsorbed by shale and this causes CH_(4)to be released from the adsorption site.

Acute Effects of Personal Ozone Exposure on Biomarkers of Inflammation,Oxidative Stress,and Mitochondrial Oxidative Damage-Shanghai Municipality,China,May-October 2016

Summary What is already known on this topic?It remains inconclusive whether short-term ozone exposure can cause an inflammatory response and oxidative damage in the circulatory system,particularly at low concentrations.What is added by this report?This study made an accurate exposure assessment by conducting personal ozone monitoring,thus minimizing the exposure misclassification commonly found in previous environmental epidemiological studies.

Short-Term Exposure to Ambient Ozone and Outpatient Visits for Respiratory Diseases-5 Cities, China, 2013−2015

Summary What is already known about this topic?Few studies have elucidated the relationships between ambient ozone and respiratory morbidity,especially in developing countries.What is added by this report?This study involved 5 cities in China with a wide variation in ozone concentrations and therefore could add credible evidence for the associations between short-term ozone exposure and increased respiratory morbidity.