AI Fairness-From Machine Learning to Federated Learning

This article reviews the theory of fairness in AI-frommachine learning to federated learning,where the constraints on precision AI fairness and perspective solutions are also discussed.For a reliable and quantitative evaluation of AI fairness,many associated concepts have been proposed,formulated and classified.However,the inexplicability of machine learning systems makes it almost impossible to include all necessary details in the modelling stage to ensure fairness.The privacy worries induce the data unfairness and hence,the biases in the datasets for evaluating AI fairness are unavoidable.The imbalance between algorithms’utility and humanization has further reinforced suchworries.Even for federated learning systems,these constraints on precision AI fairness still exist.Aperspective solution is to reconcile the federated learning processes and reduce biases and imbalances accordingly.

Effect of ternary transition metal sulfide FeNi_(2)S_(4)on hydrogen storage performance of MgH_(2)

Hydrogen storage is a key link in hydrogen economy,where solid-state hydrogen storage is considered as the most promising approach because it can meet the requirement of high density and safety.Thereinto,magnesium-based materials(MgH_(2))are currently deemed as an attractive candidate due to the potentially high hydrogen storage density(7.6 wt%),however,the stable thermodynamics and slow kinetics limit the practical application.In this study,we design a ternary transition metal sulfide FeNi_(2)S_(4)with a hollow balloon structure as a catalyst of MgH_(2)to address the above issues by constructing a MgH_(2)/Mg_(2)NiH_(4)-MgS/Fe system.Notably,the dehydrogenation/hydrogenation of MgH_(2)has been significantly improved due to the synergistic catalysis of active species of Mg_(2)Ni/Mg_(2)NiH_(4),MgS and Fe originated from the MgH_(2)-FeNi_(2)S_(4)composite.The hydrogen absorption capacity of the MgH_(2)-FeNi_(2)S_(4)composite reaches to 4.02 wt%at 373 K for 1 h,a sharp contrast to the milled-MgH_(2)(0.67 wt%).In terms of dehydrogenation process,the initial dehydrogenation temperature of the composite is 80 K lower than that of the milled-MgH_(2),and the dehydrogenation activation energy decreases by 95.7 kJ·mol-1 compared with the milled-MgH_(2)(161.2 kJ·mol^(-1)).This method provides a new strategy for improving the dehydrogenation/hydrogenation performance of the MgH_(2)material.

Broad Federated Meta-Learning of Damaged Objects in Aerial Videos

We advanced an emerging federated learning technology in city intelligentization for tackling a real challenge-to learn damaged objects in aerial videos.Ameta-learning system was integrated with the fuzzy broad learning system to further develop the theory of federated learning.Both the mixed picture set of aerial video segmentation and the 3D-reconstructed mixed-reality data were employed in the performance of the broad federated meta-learning system.The study results indicated that the object classification accuracy is up to 90%and the average time cost in damage detection is only 0.277 s.Consequently,the broad federated meta-learning system is efficient and effective in detecting damaged objects in aerial videos.

多种碳正离子的结构和稳定性问题的探讨

采用DFT方法计算了多种普通碳正离子、烯丙基型碳正离子以及特别稳定的α-氨基和α-羟基碳正离子的结构和能量。结果表明,普通碳正离子依靠形成超共价结构、重排和超共轭效应获得稳定,烯丙基型碳正离子依靠共轭效应获得稳定。α-羟基和α-氨基碳正离子的稳定性特别高,分别相当于或高于环丙烯碳正离子。最后,本文还建议了氨基和羟基对碳正离子的不同稳定方式。

The electrochemical characteristics of AB_(4)-type rare earth-Mg-Ni-based superlattice structure hydrogen storage alloys for nickel metal hydride battery

Rare earth-Mg-Ni-based alloys with superlattice structures are new generation negative electrode materials for the nickel metal hydride batteries.Among them,the novel AB_(4)-type superlattice structure alloy is supposed to have superior cycling stability and rate capability.Yet its preparation is hindered by the crucial requirement of temperature and the special composition which is close to the other superlattice structure.Here,we prepare rare earth-Mg-Ni-based alloy and study the phase transformation of alloys to make clear the formation of AB_(4)-type phase.It is found Pr_(5)Co_(19)-type phase is converted from Ce_(5)Co_(19)-type phase and shows good stability at higher temperature compared to the Ce_(5)Co_(19)-type phase in the range of 930-970℃.Afterwards,with further 5℃increasing,AB_(4)-type superlattice structure forms at a temperature of 975℃by consuming Pr_(5)Co_(19)-type phase.In contrast with A_(5)B_(19)-type alloy,AB_(4)-type alloy has superior rate capability owing to the dominant advantages of charge transfer and hydrogen diffusion.Besides,AB_(4)-type alloy shows long lifespan whose capacity retention rates are 89.2%at the 100;cycle and 82.8%at the 200;cycle,respectively.AB_(4)-type alloy delivers 1.53 wt.%hydrogen storage capacity at room temperature and exhibits higher plateau pressure than Pr_(5)Co_(19)-type alloy.The work provides novel AB_(4)-type alloy with preferable electrochemical performance as negative electrode material to inspire the development of nickel metal hydride batteries.

Can soil respiration estimate neglect the contribution of abiotic exchange?

This study examines the hypothesis that soil respiration can always be interpreted purely in terms of biotic processes, neglecting the contribution of abiotic exchange to COg fluxes in alkaline soils of arid areas that characterize 5% of the Earth＇s total land surface. Analyses on flux data collected from previous studies suggested reconciling soil respiration as organic （root/microbial respiration） and inorganic （abiotic CO2 exchange） respiration, whose contributions in the total CO2 flux were determined by soil alkaline content. On the basis of utilizing mete- orological and soil data collected from the Xinjiang and Central Asia Scientific Data Sharing Platform, an incorpo- rated model indicated that inorganic respiration represents almost half of the total CO2 flux. Neglecting the abiotic module may result in overestimates of soil respiration in arid alkaline lands, which partly explains the long-sought ＂missing carbon sink＂.

Modeling the contribution of abiotic exchange to CO_2 flux in alkaline soils of arid areas

Recent studies on alkaline soils of arid areas suggest a possible contribution of abiotic exchange to soil CO2 flux(Fc).However,both the overall contribution of abiotic CO2 exchange and its drivers remain unknown.Here we analyzed the environmental variables suggested as possible drivers by previous studies and constructed a function of these variables to model the contribution of abiotic exchange to Fc in alkaline soils of arid areas.An automated flux system was employed to measure Fc in the Manas River Basin of Xinjiang Uygur autonomous region,China.Soil pH,soil temperature at 0–5 cm(Ts),soil volumetric water content at 0–5 cm(θs)and air temperature at10 cm above the soil surface(Tas)were simultaneously analyzed.Results highlight reduced sensitivity of Fc to Ts and good prediction of Fc by the model Fc=R10Q10(Tas–10)/10+r7q7(pH–7)+λTas+μθs+e which represents Fc as a sum of biotic and abiotic components.This presents an approximate method to quantify the contribution of soil abiotic CO2 exchange to Fc in alkaline soils of arid areas.

Carboniferous tectono-magmatic evolution of the northern Luliang arc: evidence from geochemistry and petrography of Carboniferous volcanic rocks in the northern Luliang Uplift,NW China

The Northern Junggar Basin experienced extensive subduction and a complex tectono-magmatic evolution during the Late Paleozoic,resulting in a heterogeneous distribution of volcanic rocks in the Junggar Basin.In this study,the Carboniferous tectono-magmatic evolution of the northern Luliang arc was described by exploring the petrography and geochemistry of Carboniferous volcanic rocks collected from well Y-2 and outcrop WW' in the northern Luliang Uplift.The distribution,types,and formation ages of these volcanic rocks were characterized and the volcanic sequence in well Y-1 was divided into upper and lower parts according to vertical variations in selected geochemical data.Then the petrogenesis and tectonic settings of different volcanic rocks were evaluated and this was used to infer the tectonomagmatic evolution of the northern Luliang arc during the Carboniferous.The results indicate that:(1) Carboniferous high-K calc-alkali andesite-dacite associations are distributed in the west of the northern Luliang Uplift,and Lower Carboniferous calc-alkali basalt-dacite-rhyolite assemblages are preserved in its east.(2) The intermediateacid volcanic rocks in wells Y-1 and Y-2 were derived from calc-alkali basaltic magma through melting of the juvenile lower crust,and geochemical variations indicate increasing addition of slab melting in a subduction-related arc environment.The bimodal volcanic rocks from outcrop WW' were derived from lithospheric underplating of basaltic magma in an intra-arc extensional setting.(3) The closure of the eastern Keramaili Oceanic basin occurred before the Early Carboniferous,and the tectono-magmatic difference between the east and the west of the northern Luliang Uplift appeared before the Carboniferous period.

Developing Honeybee Breeding Industry to Revitalize Rural Economy

[Objectives]In Tibet,the efficiency of beekeeping industry is low,the abundant nectariferous plants and the non-polluting natural ecological environment are not fully utilized,the pollination of rapeseed and other insect-based crops is insufficient,and benefits are not brought by beekeeping.[Methods]In response to these problems,Italian bees were first introduced since 2004,and combined with the special natural ecological environment of Tibet,researches on Italian bee biology,queen rearing technology,overwintering technology,and breeding management technology were carried out in high altitude areas.[Results]Through many years of effort,it has filled the gap in bee breeding technology at an altitude of about 4000 m.[Conclusions]It is expected to provide a new pillar industry for Tibetan farmers and herdsmen to increase production and income.

芳香烃章节教学中若干问题的计算与探讨

采用6-311G(d)/B3LYP计算方法,通过对多个有机物和中间体的分子结构和能量的计算,探讨了如下问题:(1)Birch还原的区域选择性问题;(2)氯甲基的电子效应问题;(3)反芳香性对有机物结构影响问题;(4)多环化合物局部芳香性问题。这些计算与探讨丰富了有机化学教学内容,有利于大学生对芳香烃章节的学习。

Catalytic effect of MOF-derived transition metal catalyst FeCoS@C on hydrogen storage of magnesium

The introduction of the heterogeneous catalysts with high activity can significantly improve hydrogen storage performance of MgH_(2),therefore,in this paper,we synthesize a carbon-supported transition metal compound,FeCoS@C derivative from ZIF-67,by utilizing the in situ formed C dispersive multiphase Mg_(2)Co,α-Fe,Co_(3)Fe_(7),and MgS to implement catalysis to MgH_(2).Noteworthily,MgH_(2)-FeCoS@C rapidly ab-sorbs 6.78 wt%H_(2)within 60 s at 573 K and can also absorb 4.56 wt%H_(2)in 900 s at 473 K.Besides,the addition of FeCoS@C results in decreasing of the initial dehydrogenation temperatures of MgH_(2)from 620 to 550 K.The dehydrogenation activation energy of MgH_(2)decreases from 160.7 to 91.9 kJ mol^(-1).Studies show that the Mg_(2)Co,α-Fe,and Co_(3)Fe_(7)act as“hydrogen channels”to accelerate hydrogen transfer due to the presence of transition metals,and MgS with excellent catalytic effect formed from MgH_(2)-FeCoS@C provides a strong and stable catalytic effect.Besides,the carbon skeleton obtained by the carbonization of ZIF-67 not only serves as a dispersion for the multiphase catalytic system,but also provides more active sites for the catalysts.Our study shows that the multiphase and multiscale catalytic system provides an effective strategy for improving the hydrogen storage performance of MgH_(2).

Geochemistry of rare earth elements and yttrium in Late Permian coals from the Zhongliangshan coalfield, southwestern China

Rare earth elements and yttrium(REY)in coal deposits are considered promising alternative sources for these resources owing to their increasing global demand.This paper reports the geochemical characteristics of REY in the Late Permian coals from an underground K1a seam section of the Zhongliangshan coalfield in Chongqing,southwestern China.The mineralogy,degree of enrichment,distribution patterns,modes of occurrence,and sediment origin of REY were investigated.Compared with the average of world coals,the concentration of REY in the K1a coals were normal,dominated by light REY(LREY),with less medium and heavy REY(MREY,HREY).The fractionation degree of the MREY and HREY are higher than that of LREY in most K1a coal samples,deduced from the mixed enrichment type of REY,mainly including M-H-type,and a few L-M type and H-type.In addition,the combination of anomalies of Ce,Eu,Gd,and Al_(2)O_(3)/TiO_(2) parameters,the terrigenous materials in the K1a coal were derived from the felsic-intermediate rocks at the top of the Emeishan basalt sequence,and the samples were affected by seawater intrusion during early peat accumulation.Although the minerals primarily consist of kaolinite,illite,pyrite,and small amounts of quartz,calcite and anatase,REY are correlated with ash yield,SiO2,and Al_(2)O_(3),revealing that the REY mainly occur in aluminosilicate minerals,especially kaolinite and illite.Meanwhile,REY positively relate to P_(2)O_(5) and Zr,which may exist in phosphate-containing minerals or zircon.Furthermore,most samples in the K1a coal or ash do not reach the cut-off grade for the beneficial recovery of REY.With the exception of central Guizhou,southwestern Chongqing,and the junction of western Guizhou and northeastern Yunnan,the REY content in coals from southwestern China are high,and its by-products are suitable as potential REY sources.

中国煤系中关键金属资源:富集类型与分布

煤是特殊的沉积有机矿产,资源量巨大.以有机质为主要物质组成的特征决定了煤的吸附障和还原障性能,因而可以在特定地质条件下富集多种关键金属,能够形成大型、超大型甚至异常超大型规模的矿床,即"煤型关键金属矿床"这种新的矿床类型.煤型关键金属矿产已成为矿产资源勘探的新领域、新蹊径和重要方向.本文选择性地总结了煤型锗矿床、煤型镓铝矿床、煤型稀土矿床,以及煤型铌-锆-稀土-镓矿床的分布特征与成矿机制,并简要介绍了中国煤中铍、钪、锂、镁、钒和铼的富集与分布.不同煤型关键金属矿床具有特定的成矿地质环境,研究这些矿床的分布、富集成因以及金属赋存机制,有助于金属矿床的预测、勘探和开发.此外,这些矿床还是研究有机质和无机质相互作用的难得案例,能够帮助解决区域地质演化等重大科学问题,对发展和完善已有的关键金属成矿理论、保障关键金属安全供给、发展循环经济、减轻环境污染都具有重要意义.

协同芳香亲核取代反应

芳香亲核取代反应被有机化学家广泛地用于有机化合物的合成,是最重要的合成反应之一。教材中对于该反应机理的介绍为分步过程,但是随着研究的深入,通过协同过程的芳香亲核取代反应已经被广泛证实。本文简要回顾了分步进行的芳香亲核取代反应,重点介绍了协同芳香亲核取代反应的几个实例,阐述了反应设计对机理研究的重要性。通过将科研成果融入教学过程,有助于进一步加深对芳香亲核取代反应的理解。

水系锌离子电池研究进展和挑战

水系锌离子电池(AZIBs)作为一种新兴电池储能技术,具有安全性高、价格低廉、能量密度高、环境友好、易制造等优点,在大规模储能等领域具有良好的应用价值和前景,近年引起了人们的广泛关注且发展迅速.作者从目前AZIBs存在的科学问题出发,综述了AZIBs在正负极材料及电解液方面取得的重要进展,对已开发的多种正极材料的特点及其电化学反应机理进行了分析和总结,讨论了金属Zn负极面临的挑战和改善策略,分析了不同水系电解液的特征及其优化方案,并对这一新兴电池技术面临解决的科学问题和未来实际应用面临的技术挑战进行了总结和展望.

Quantum dots protect against MPP＋-induced neurotoxicity in a cell model of Parkinson＇s disease through autophagy induction

Autophagy is a basic cellular process that decomposes damaged organelles and aberrant proteins. Dysregulation of autophagy is implicated in pathogenesis of neurodegenerative disorders, including Parkinson's disease(PD). Pharmacological compounds that stimulate autophagy can provide neuroprotection in models of PD. Nanoparticles have emerged as regulators of autophagy and have been tested in adjuvant therapy for diseases. In this present study, we explore the effects of quantum dots(QDs) that can induce autophagy in a cellular model of Parkinson's disease. Cd Te/Cd S/Zn S QDs protect differentiated rat pheochromocytoma PC12 cells from MPP+-induced cell damage, including reduced viability, apoptosis and accumulation of α-Synuclein, a characteristic protein of PD. The protective function of QDs is autophagy-dependent. In addition, we investigate the interaction between quantum dots and autophagic pathways and identify beclin1 as an essential factor for QDs-induced autophagy. Our results reveal new promise of QDs in the theranostic of neurodegenerative diseases.

Species turnover drives grassland community to phylogenetic clustering over long-term grazing disturbance

放牧通过改变草地群落物种组成和生物多样性,进而影响草地群落结构,对草地生态系统服务和功能产生深远的影响。然而,有关系统发育多样性和系统发育群落结构对长期放牧干扰的响应和适应的研究仍然很少,尤其是对于分布在极端环境中的生态系统。我们在青藏高原高寒草地上开展了多放牧强度的试验,探讨放牧干扰对植物系统发育多样性和群落结构的影响。研究发现,放牧干扰增加了植物群落的物种丰富度,促进了群落物种周转,从而改变了群落物种组成。低强度放牧对系统发育多样性和群落结构没有显著影响,而高强度放牧促使群落结构由分散向聚集变化。高强度放牧通过强烈的环境过滤作用,选择了一些耐牧的草地植物物种。在高强度放牧条件下,草地群落的聚集结构由近缘种的入侵和远缘种的丢失共同驱动。在植物功能性状水平上,我们发现与低强度放牧相比,高强度放牧通过改变根系深度对物种入侵产生影响,在很大程度上提升了物种的入侵性。我们的研究强调,仅仅利用物种丰富度和多样性并不能全面反映放牧干扰对草地群落的影响,而且在以后的放牧生态学研究中应该更加关注物种周转对群落系统发育多样性和群落结构的影响。

Photosensitive damage of lysozyme caused by pazufloxacin and the protective effect of ferulic acid

Laser flash photolysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) experiments were carried out to study the photosensitive damage induced by pazufloxacin(PAX) and the protection of lysozyme(Lyso) by ferulic acid(FCA), an active antioxidant. Transient absorption spectra revealed electron transfer from Lyso and FCA to 3PAX*, with respective bimolecular reaction rate constants of 6.3×107 and 1.4×1010 dm3/(mol s). A pulse radiolysis study was also performed to investigate the formation of Lyso radical cations. Results showed that FCA effectively inhibited the cross-linking of protein induced by fluoroquinolones. Finally, a mechanism of the protective effect of FCA on Lyso was proposed.

Case study:A simple optical inverse problem from a geometrical optics point of view

In this paper,we revisit the simple problem of reflection from a dielectric sphere for light rays and define a form of optical inverse problem in the sense of geometrical optics(GO).A general analytic formula is derived to obtain the refraction index of the sphere for any incidence light to emerge in a deflected angle.Numerical wave simulation and ray tracing are performed to verify the inverse formulae derived.