Selective core-shell doping enabling high performance 4.6 V-LiCoO_(2)

Constructing robust surface and bulk structure is the prerequisite for realizing high performance high voltage LiCoO_(2)(LCO).Herein,we manage to synthesize a surface Mg-doping and bulk Al-doping coreshell structured LCO,which demonstrates excellent cycling performance.Half-cell shows 94.2%capacity retention after 100 cycles at 3.0-4.6 V(vs.Li/Li^(+))cycling,and no capacity decay after 300 cycles for fullcell test(3.0-4.55 V).Based on comprehensive microanalysis and theoretical calculations,the degradation mechanisms and doping effects are systematically revealed.For the undoped LCO,high voltage cycling induces severe interfacial and bulk degradations,where cracks,stripe defects,fatigue H2 phase,and spinel phase are identified in grain bulk.For the doped LCO,Mg-doped surface shell can suppress the interfacial degradations,which not only stabilizes the surface structure by forming a thin rock-salt layer but also significantly improves the electronic conductivity,thus enabling superior rate performance.Bulk Al-doping can suppress the lattice"breathing"effect and the detrimental H3 to H1-3 phase transition,which minimizes the internal strain and defects growth,maintaining the layered structure after prolonged cycling.Combining theoretical calculations,this work deepens our understanding of the doping effects of Mg and Al,which is valuable in guiding the future material design of high voltage LCO.

Deciphering the critical effect of cathode-electrolyte interphase by revealing its dynamic evolution

Cathode electrolyte interphase(CEI)layer plays a crucial role in determining the electrochemical performance of lithium-ion batteries.Limited by the sensitive nature of CEI and the lack of characterization techniques,its dynamic evolution during cycling,its formation mechanism,and its specific impact on battery performance are not yet fully understood.Herein,we systematically investigate the dynamic evolution of CEI layer and its critical effect on the cycling performance of LiCoO_(2)cathode by diverse characterization techniques.We find that cycling voltage plays a key role in affecting CEI formation and evolution,and a critical potential(4.05 V vs.Li)is identified,which acts as the switching potential between CEI deposition and decomposition.We show that CEI starts deposition in the discharge process when the potential is below 4.05 V,and CEI decomposition occurs when the potential is higher than 4.05 V.When the battery is cycled below such a critical potential,a stable CEI layer is developed,which leads to superior cycling stability.When the battery is cycled above such a critical potential,a CEI-free cathode interface is observed,which also demonstrates good cycle stability.However,when the critical potential falls in the cycling voltage range,CEI deposition and decomposition are repeatedly switched on during cycling,leading to the dynamically unstable CEI layer.The unstable CEI layer causes continuous interfacial reaction and degradation,resulting in battery performance decay.Our work deepens the understanding of the CEI formation and evolution mechanisms,and clarifies the critical effect of CEI layer on cycling performance,which provides new insights into stabilizing the electrode-electrolyte interface for high-performance rechargeable batteries.

Cross-Domain Data Traceability Mechanism Based on Blockchain

With the application and development of blockchain technology,many problems faced by blockchain traceability are gradually exposed.Such as cross-chain information collaboration,data separation and storage,multisystem,multi-security domain collaboration,etc.To solve these problems,it is proposed to construct trust domains based on federated chains.The public chain is used as the authorization chain to build a cross-domain data traceability mechanism applicable to multi-domain collaboration.First,the architecture of the blockchain cross-domain model is designed.Combined with the data access strategy and the decision mechanism,the open and transparent judgment of cross-domain permission and cross-domain identity authentication is realized.And the public chain consensus node election mechanism is realized based on PageRank.Then,according to the characteristics of a nonsingle chain structure in the process of data flow,a data retrievalmechanism based on a Bloom filter is designed,and the cross-domain traceability algorithm is given.Finally,the safety and effectiveness of the traceability mechanism are verified by security evaluation and performance analysis.

An Integrated Analysis on the Synergistic Reduction of Carbon and Pollution Emissions from China’s Iron and Steel Industry

Decarbonization and decontamination of the iron and steel industry(ISI),which contributes up to 15%to anthropogenic CO_(2) emissions(or carbon emissions)and significant proportions of air and water pollutant emissions in China,are challenged by the huge demand for steel.Carbon and pollutants often share common emission sources,indicating that emission reduction could be achieved synergistically.Here,we explored the inherent potential of measures to adjust feedstock composition and technological structure and to control the size of the ISI to achieve carbon emission reduction(CER)and pollution emission reduction(PER).We investigated five typical pollutants in this study,namely,petroleum hydrocarbon pollutants and chemical oxygen demand in wastewater,particulate matter,SO_(2),and NO_(x) in off gases,and examined synergies between CER and PER by employing cross elasticity for the period between 2022 and 2035.The results suggest that a reduction of 8.7%-11.7%in carbon emissions and 20%-31%in pollution emissions(except for particulate matter emissions)could be achieved by 2025 under a high steel scrap ratio(SSR)scenario.Here,the SSR and electric arc furnace(EAF)ratio serve critical roles in enhancing synergies between CER and PER(which vary with the type of pollutant).However,subject to a limited volume of steel scrap,a focused increase in the EAF ratio with neglection of the available supply of steel scrap to EAF facilities would lead to an increase carbon and pollution emissions.Although CER can be achieved through SSR and EAF ratio optimization,only when the crude steel production growth rate remains below 2.2%can these optimization measures maintain the emissions in 2030 at a similar level to that in 2021.Therefore,the synergistic effects between PER and CER should be considered when formulating a development route for the ISI in the future.

Landslide identification using machine learning

Landslide identification is critical for risk assessment and mitigation.This paper proposes a novel machinelearning and deep-learning method to identify natural-terrain landslides using integrated geodatabases.First,landslide-related data are compiled,including topographic data,geological data and rainfall-related data.Then,three integrated geodatabases are established;namely,Recent Landslide Database(Rec LD),Relict Landslide Database(Rel LD)and Joint Landslide Database(JLD).After that,five machine learning and deep learning algorithms,including logistic regression(LR),support vector machine(SVM),random forest(RF),boosting methods and convolutional neural network(CNN),are utilized and evaluated on each database.A case study in Lantau,Hong Kong,is conducted to demonstrate the application of the proposed method.From the results of the case study,CNN achieves an identification accuracy of 92.5%on Rec LD,and outperforms other algorithms due to its strengths in feature extraction and multi dimensional data processing.Boosting methods come second in terms of accuracy,followed by RF,LR and SVM.By using machine learning and deep learning techniques,the proposed landslide identification method shows outstanding robustness and great potential in tackling the landslide identification problem.

Recent Advances and Applications Toward Emerging Lithium–Sulfur Batteries:Working Principles and Opportunities

Lithium–sulfur(Li-S)batteries have been considered as promising candidates for large-scale high energy density devices due to the potentially high energy density,low cost,and more pronounced ecological compatibility.However,the complex Li-S conversion reactions,unsatisfactory battery performance,and unsafe metallic Li anode restrict the development of Li-S batteries to achieve commercialization.This review mainly focuses on three aspects which are the remaining challenges,recent advances,and applications in Li-S batteries.Firstly,this review portrays Li-S conversion chemistry involving the multi-step and multi-electron reaction mechanism,as well as the remaining challenges.Then,the scientific strategies and very recent advances of the cathode,electrolyte,lithium anode,and other constituent parts of Li-S batteries are detailly summed up,as well as their advantages and limitations.For the sake of promoting the Li-S batteries practicalization,next section is primarily concerned with problems,the corresponding solutions,and application scenarios of practical pouch cells.Finally,the important findings as guidelines and some future directions as trends for developing emerging Li-S batteries are briefly summarized.

In situ growth of 3D walnut-like nano-architecture Mo-Ni2P@NiFeLDH/NF arrays for synergistically enhanced overall water splitting

The in situ growth of nano-array on material structure is a novel and high-efficient strategy to design catalysts,however,it still remains a challenge to fabricate unique nano-architecture electrocatalyst with prominent activity and superior durability for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER).Herein,a unique nano-architecture catalyst is successfully synthesized by using NiFe LDH nanosheets as framework to the in situ growth Mo-doped Ni2 P ultrafine nanosheets(marked as Mo-Ni2 P@NiFe LDH/NF).The unique 3 D core-shell nano-architecture is favorable for enhancing electron transfer/mass diffusion,providing abundant active sites,prompting O2/H2 gas release,and creating the synergistic effect between Mo-Ni2 P and NiFe LDH.Therefore,comparing with pure NiFe LDH/NF and MoNi2 P/NF electrodes,walnut-like Mo-Ni2 P@Ni Fe LDH/NF catalyst exhibits significantly improved electrocatalytic activities and durability towards OER(269 m V@40 m A cm^-2),HER(82 mV@10 mA cm^-2),and overall water splitting(1.46 V@10 m A cm^-2),respectively.Such electrocatalytic activity of Mo-Ni2 P@NiFe LDH/NF is comparable with that of majority reported non-precious metal catalysts and even precious catalysts(IrO2 and Pt/C).This work presents a new perspective strategy to fabricate ingeniously bifunctional electrocatalysts with well-designed structure and superior performance for clean energy conversion technologies or storage devices.

Fuzzy Reliability Analysis of One Paralleling System

In this paper,we analyze the fuzzy reliability of paralleling system,focusing on the situation of the early failure mode.The early failure mode of fuzzy reliability mainly obeys the Weibull distribution.Based on this,we obtain the distribution function,density function,failure function,reliability function and the formula of the mean time to failure.For the paralleling system composed of multiple components,C1,C2,???,Cn,especially whenη=1,we also obtain the corresponding formulas.Finally,we cite an example to verify the formula and deepen the understanding.

超疏水材料的研究进展

近年来,油水分离技术越来越受到人们的重视,而具有特殊润湿性的油水分离材料成为研究热点。文中综述了超疏水材料在油水分离领域的研究进展。简单地介绍了构建超疏水材料的基本原理,归纳总结了超疏水材料的制备方法如水热法、刻蚀法、静电纺丝技术、自组装技术、溶胶-凝胶法和沉积法等方法,并且讨论了不同方法的优缺点及前景,为今后超疏水材料的发展提供理论建议。

Advanced prediction of tunnel boring machine performance based on big data

Predicting the performance of a tunneling boring machine is vitally important to avoid any possible accidents during tunneling boring.The prediction is not straightforward due to the uncertain geological conditions and the complex rock-machine interactions.Based on the big data obtained from the 72.1 km long tunnel in the Yin-Song Diversion Project in China,this study developed a machine learning model to predict the TBM performance in a real-time manner.The total thrust and the cutterhead torque during a stable period in a boring cycle was predicted in advance by using the machine-returned parameters in the rising period.A long short-term memory model was developed and its accuracy was evaluated.The results show that the variation in the total thrust and cutterhead torque with various geological conditions can be well reflected by the proposed model.This real-time predication shows superior performance than the classical theoretical model in which only a single value can be obtained based on the single measurement of the rock properties.To improve the accuracy of the model a filtering process was proposed.Results indicate that filtering the unnecessary parameters can enhance both the accuracy and the computational efficiency.Finally,the data deficiency was discussed by assuming a parameter was missing.It is found that the missing of a key parameter can significantly reduce the accuracy of the model,while the supplement of a parameter that highly-correlated with the missing one can improve the prediction.

Influence of hypoxia-inducible factor 1-alpha on neuronal apoptosis in a rat model of hypoxia-or hypoxia-ischemia-induced brain injury

BACKGROUND： In addition to neuroprotective genes, the targeted genes of hypoxia-inducible factor 1α （HIF-1α） include pro-apoptotic genes. However, the influence of HIF-1α on neuronal apoptosis in hypoxia-ischemia remains poorly understood. OBJECTIVE： To investigate the relationship between HIF-1α expression and neuronal apoptosis in hypoxia or hypoxia-ischemia brain injury and to determine the role of HIF-1α in regulating neuronal apoptosis. DESIGN, TIME AND SETTING： A randomized, controlled animal experiment was performed at the Laboratory of Children Neurology of Sichuan University between May 2006 and May 2007. MATERIALS： In situ cell death detected kit was provided by Roche, USA; rabbit anti-mouse HIF-1α polyclonal antibody was purchased from Santa Cruz Biotechnologies, USA; rabbit anti-mouse cleaved caspase-3 polyclonal antibody was purchased from Chemicon, USA. METHODS： A total of 36 Sprague Dawley rats aged 10 days were randomly assigned to 3 groups： sham-surgery, hypoxia, and hypoxia-ischemia, with 12 rats per group. The rats were treated at 3 time points： 4, 8, and 24 hours, with 4 rats per time point. In the hypoxia-ischemia group, the right common carotid artery was exposed and permanently ligated through a midline cervical incision. A 2.5-hour exposure to hypoxia （8% O2/92% N2） was used to induce hypoxia-ischemia injury. In the hypoxia group, rats were exposed to hypoxia without ligation of the common carotid artery. In the sham-surgery group, the common carotid artery was exposed without ligation or hypoxia. MAIN OUTCOME MEASURES： Histopathological changes, HIF-1α and activated caspase-3 protein expression, integrated optical density of positive cells, and apoptosis-positive cells. RESULTS： Hematoxylin and eosin staining showed that neuronal degeneration and edema was most prominent at 24 hours after hypoxia-ischemia. HIF-1α protein expression was significantly upregulated at 4 hours, peaked at 8 hours, and decreased at 24 hours after hypoxia or hypoxia-ischemia. HIF-1α protein expression was significant greater in the hypoxia and hypoxia-ischemia groups compared with the sham-surgery group （P 〈 0.01）. Activated caspase-3 protein expression began to increase at 4 and 8 hours following hypoxia or hypoxia-ischemia and was significantly upregulated at 24 hours. Activated caspase-3 protein expression remained at low levels in the sham controls compared with the hypoxia and hypoxia-ischemia groups （P〈 0.01）. TUNEL staining showed that the number of apoptotic cells significantly increased at 24 hours after hypoxia or hypoxia-ischemia. In addition, HIF-1α protein expression was greater in the hypoxia group compared with the hypoxia-ischemia group at the same time point （P 〈 0.05）. However, activated caspase-3 expression and the number of TUNEL-positive cells were less in the hypoxia group compared with the hypoxia-ischemia group at the same time point （P〈 0.05）. CONCLUSION： HIF-1α played a neuroprotective role following hypoxia-ischemia brain injury.

信息疫情视角下儿童家长的疫苗犹豫机制研究

COVID-19大流行带来了一系列问题,在信息疫情与信息过载的背景下,本文围绕媒体负面信息对儿童家长疫苗犹豫的影响展开研究,以期为公众更好地理解家长疫苗犹豫问题与制定儿童免疫政策提供实证参考。2021年7—8月本研究在全国范围内线上招募407名3~17岁儿童和青少年家长,以问卷的形式展开调查,随后通过结构方程模型验证。研究发现,国内家长群体普遍存在儿童疫苗犹豫,负面信息是其新冠疫苗犹豫的核心因素,个体对疫苗信息的风险感知对于疫苗犹豫的影响作用仅次于负面信息,而对信息的效能感知能够降低疫苗犹豫,家长的疫苗素养在信息采纳与疫苗犹豫中发挥调节作用。

Controllable synthesis of Au-TiO2 nanodumbbell photocatalysts with spatial redox region

Photocatalytic water splitting has increasingly attracted attention as one of the most useful methods of converting solar energy into chemical fuel.However,the undesirable reverse reaction significantly limits the enhancement of efficiency.Herein,we fabricated an Au nanorods/TiO2 nanodumbbells structure photocatalyst(Au NRs/TiO2 NDs)via a facile synthetic strategy,which has spatially separated oxidation and reduction reaction zones.Owing to the unique structure,the charge separation of these photocatalysts can be significantly improved and the reverse reaction can be efficiently inhibited.The photogenerated electrons were injected from the TiO2 to the Au NRs,and a positively charged TiO2 region and negatively charged Au region were formed under UV irradiation.An enhanced hydrogen production performance was obtained compared with that seen in normal Au-TiO2 heterostructure.Under optimized conditions,the H2-production rate can reach up to 60,264μmol/g/h,about six times higher than previously reported Au/TiO2 photocatalysts.Besides this,our work also demonstrates the key factors of precise synthesis of the Au NRs/TiO2 NDs structure,which provides a new perspective and experience for the design of similar catalysts.

Structural Characteristics of Lycium ruthenicum Community & Soil Properties on Different Types of Desert Rangeland in the Lower Reaches of Shiyang River

[Objectives] To study structural characteristics of Lycium ruthenicum community and soil properties on different types of desert rangeland in the lower reaches of Shiyang River, and provide theoretical basis for ecological protection and management in the lower reaches of Shiyang River. [Methods] One-way ANOVA analysis and correlation analysis were carried out with the aid of SPSS19.0 software for different types of desert rangeland soils. [Results](i) Among the communities surveyed, there are 31 species belonging to 9 families and 28 genera, including 12 shrub plants, 8 perennial herbs and 11 annual herbs. There are more single genus, occupying 50% of total genus. L. ruthenicum occupies an important position in the community with relatively higher importance value. It plays a dominated role in the community.(ii) In the soils with depths of 0-10 cm, 10-20 cm, 20-40 cm and 40-60 cm in different types of desert rangeland, the organic carbon contents in the saline alkali soil were the highest, with the values of 1.08%, 0.98%, 0.89% and 0.972%, respectively. Compared with that in sandy land, soil organic carbon in saline alkali land(0-10 cm) had the significant difference(P<0.05), available soil potassium in saline alkali land(except the depth of 20-40 cm) and the total phosphorus content in saline alkali land(0-10 cm) had the significant difference(P<0.05), the total soil nitrogen, alkali-hydrolyzable nitrogen, available phosphorus and the total potassium content had no significant difference(P>0.05). Soil organic carbon, available soil phosphorus in saline alkali land, total soil potassium on sand dune and total soil phosphorus in saline alkali land and gravel in different soil layers of the same type of desert rangeland had distinct aggregation effect.(iii) The soil microbial biomass in different types of desert rangeland displayed from high to low as saline alkali land > sandy land > fixed and semi fixed sandy land > gravel. The discrepancy of soil microbial biomass varied in different types of desert rangeland. The four soil enzyme activities in salinization was the highest. Soil invertase activity in saline alkali land in different soil layers were the highest. For different soil layers in the same type of desert rangeland, soil microbial biomass and invertase decreased gradually with the deepening of soil layer.(iv) There was a significant positive correlation between soil organic matter and microbial biomass carbon, microbial biomass nitrogen, phosphatase and sucrase(P<0.01), and a significant positive correlation with urease and catalase(P<0.05). Phosphorus content was significant positively correlated with urease, phosphatase and invertase(P<0.01), and positively correlated with microbial biomass carbon(P<0.05). Soil available potassium content was significant positively correlated with microbial and phosphatase(P<0.01). [Conclusions] The species of L. ruthenicum community and soil properties on different types of desert rangeland in the lower reaches of Shiyang River clearly shows that most species belong to a few families, and a few species belong to most families, and many species are single genus or single family. Soil organic carbon, soil available phosphorus, total phosphorus, soil microbial biomass and enzyme activity in salinization land had distinct surface aggregation effects, so salinization land provides excellent growth environment for the growth of L. ruthenicum, which is of great significance for the protection of L. ruthenicum population.

Evaluation of global niobium flow modeling and its market forecasting

Metal,as the indispensable material,is functioning the society from technology to the environment.Niobium(Nb)is considered a unique earth metal as it is related to many emerging technologies.The increasing economic growth exerts an increasing pressure on supply,which leads to its significance in the economic sector.However,few papers have addressed Nb sustainability,which forms the scope of this paper in order to start the process of Nb market forecasting based on some previous data and some assumptions.Therefore,this paper will discuss different thoughts in material substitution and the substance flow of Nb throughout a static flow using Nb global data to have a better understanding of the process of Nb from production to end of life.This shall lead to the identification of the market needs to determine its growth which is around 2.5% to 3.0%.Moreover,due to China’s huge Nb consumption which comes from the continuous development that is happening over the years,it will also briefly mention the Nb situation as well as its growth which according to statistics will grow steadily till 2030 by a rate of 4.0% to 6.0%.The results show that there should be some enhancement to Nb recycling potentials out of steel scrap.In addition,there should be more involvement of Nb in different industries as this would lead to less-used materials which can be translated to less environmental impact.

Prediction of load-displacement performance of grouted anchors in weathered granites using FastICA-MARS as a novel model

With the rising needs of better prediction of the load-displacement performance of grouted anchors in an era of developing large-scale underground infrastructures,the existing methods in literature lack an accurate analytical model for the real-life projects or rigorous understanding of the parameters such as grouting pressures.This paper proposes Fast ICA-MARS as a novel data-driven approach for the prediction of the load-displacement performance of uplift-resisting grouted anchors.The hybrid and data-driven Fast ICA-MARS approach integrates the multivariate adaptive regression splines(MARS)technique with the Fast ICA algorithm which is for Independent Component Analysis(ICA).A database of 4315 observations for 479 different anchors from 7 different projects is established.The database is then used to train,validate and compare the Fast ICA-MARS approach with the classical MARS approach.The developed Fast ICA-MARS model can provide more accurate predictions than MARS.Moreover,the developed Fast ICA-MARS model is easy to interpret since the evaluation of the parameter importance of the independent components can be conducted along with the considerations of the correlations with the original variables.It is noteworthy to point out that the grouting pressures play a central role in the proposed model,which is considered of paramount importance in engineering practices but has not been properly taken into account in any prior analytical or empirical predictive models for the load-displacement relationships.

Passively Q-switched Tm/Ho composite laser

We explored Q-switching mechanism for the newly proposed Tm/Ho composite laser via developing a hybrid resonator for separating the intra-cavity Tm laser modulated by the saturable absorber(SA).With a Cr:ZnSe SA,successful passively Q-switching process with the maximum average output power of 474 mW and the shortest pulse width of 145 ns were obtained at the pulse repetition frequency of 7.14 kHz,where dual wavelength oscillation in both 2090 nm and 2097 nm was observed.This work provides an effective way for a direct laser diode(LD)pumped Q-switched Ho laser,which is compact and accessible.Furthermore,the current SA could be replaced by the 2D materials with broadband saturable absorption such as topological insulators or transition-metal dichalcogenides for seeking novel PQS lasers.

Anthropogenic mineral generation and its potential resource supply:The case of niobium

The strategy of carbon neutrality is reshaping the global landscape of resource flow and recycling.As the final sink of geological minerals,the proliferated anthropogenic minerals,also called secondary resources,play an increasingly important role in resource supply enrichment.Niobium is a critical metal that lacks full concern for its sustainability.The fundamental principle of niobium circularity is to recycle and maintain the material as close to the manufacturing process as possible.Here we estimate the niobium-containing applications lost at their end-of-life,underscoring the imperative to minimize such disposal.Additionally,we elucidate the extraction processes for scrap and alloy quantities throughout the industry's lifecycle.Drawing from anticipated waste generated by the majority of niobium applications,a forecast indicates a potential loss of approximately 168 kt by 2090 in the absence of recycling.Contrastingly,with a recycling efficiency of 90%for niobium,the projected loss diminishes to approximately 16 kt.We delve into the significance of niobium's circular economy and explore various aspects that demand further investigation for a seamless transition from linear to circular practices.

Repercussions of COVID-19 pandemic on solid waste generation and management strategies

It has been over ten months since the beginning of the 2019 coronavirus disease(COVID-2019),and its impact on solid waste management,especially medical waste,is becoming clearer.This study systematically reviews the potential influences of the COVID-19 pandemic on medical waste,personal protection equipment waste and municipal solid waste(MSW),and discusses the corresponding measures and policies of solid waste management in typical countries.The results show that the generation of medical waste from the pandemic increased significantly,with 18%‒425%growth.It is estimated that the daily output of COVID-19 medical waste increased from 200 t/d on Feb.22 to over 29000 t/d at the end of September 2020 throughout the world.The use of personal protective equipment will continue to grow in the long-term,while the blockade and isolation measures greatly reduced the volume of commercial waste,especially for tourist cities,and part of this waste was transferred to household waste.Residents’attitudes and behavior toward food waste have changed due to the COVID-19 pandemic.In response to the pandemic,international organizations and several countries have issued new policies and guidelines and adjusted their management strategies for medical waste and MSW treatment.The pandemic has brought specific challenges to the disposal capacity of medical waste worldwide.It has also brought about the stagnation of policies related to the reduction of plastic products and waste recycling.This study will provide some useful information for managers and governmental officials on effective solid waste management during and after the COVID-19 pandemic.