SrTiO3/BiOI heterostructure: Interfacial charge separation, enhanced photocatalytic activity, and reaction mechanism

Heterostructured photocatalysts provide an effective way to achieve enhanced photocatalytic performances through efficient charge separation.Although both wide-and narrow-band-gap photocatalysts have been widely investigated,the charge separation and transfer mechanism at the contacting interface of the two has not been fully revealed.Here,a novel SrTiO3/BiOI(STB)heterostructured photocatalyst was successfully fabricated by using a facile method.The heterostructure in the photocatalyst extends the photoabsorption to the visible light range,and thus,high photocatalytic NO removal performance can be achieved under visible light irradiation.A combination of experimental and theoretical evidences indicated that the photogenerated electrons from the BiOI semiconductor can directly transfer to the SrTiO3 surface through a preformed electron delivery channel.Enhanced electron transfer was expected between the SrTiO3 and BiOI surfaces under light irradiation,and leads to efficient ROS generation and thus a high NO conversion rate.Moreover,in situ diffused reflectance infrared Fourier transform spectroscopy revealed that STB can better inhibit the accumulation of the toxic intermediate NO2 and catalyze the NO oxidation more effectively.This work presents a new insight into the mechanism of the interfacial charge separation in heterostructures and provides a simple strategy to promote the photocatalytic technology for efficient and safe air purification.

Superhydrophobic Micro/Nanostructured Copper Mesh with Self-Cleaning Property for E ective Oil/Water Separation

In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.

Experimental determination of the internuclear separation of HD^+ ion micro-cluster

Measurements of zero-degree breakup fragment energy distribution fromthe Coulomb-Explosions of 1.50965 MeV HD+ ion inicro-cluster beam are reported.Mean value of the internuclear separation of HD+ is found to be 0.12510.003 urn. Aset of high-resolution experimental arrangement and improvement of the Van-de-Graaffaccelerator are described briefly.

A Novel Method for Modification of SMPU by Micro-phase Separation Promoters

A novel method of controlling the shape memory properties of shape memory polyurethane （SMPU） by addition of micro-phase separation promoters including 1-octadecanol （ODO） and liquid paraffin （LP） is reported. The results indicate that the strain recovery temperature and the strain modulus rate （Eg/Er） were increased significantly with addition of small amount of micro-phase separation promoters. Thus it can increase the shape memory fixity rate and other shape memory behaviors of SMPU.

THE ROLES OF REACTION INHOMOGENEITY IN PHASE SEPARATION KINETICS AND MORPHOLOGY OF REACTIVE POLYMER BLENDS

The roles of reaction inhomogeneity in phase separation of polymer mixtures were described and summarized via two examples:photocross-link of polymer mixtures in the bulk state and photopolymerization of monomer in the liquid state. The reaction kinetics,the reaction-induced elastic strain and the phase separation kinetics were monitored respectively by UV-Vis spectroscopy,Mach-Zehnder interferometry and laser-scanning confocal microscopy.It was found that phase separation in the bulk state was strongly inf...

Surface assembly of cobalt species for simultaneous acceleration of interfacial charge separation and catalytic reactions on Cd_(0.9)Zn_(0.1)S photocatalyst

Although photocatalytic water splitting has excellent potential for converting solar energy into chemical energy,the challenging charge separation process and sluggish surface catalytic reactions significantly limit progress in solar energy conversion using semiconductor photocatalysts.Herein,we demonstrate a feasible strategy involving the surface assembly of cobalt oxide species(CoO_(x))on a visible-light-responsive Cd_(0.9)Zn_(0.1)S(CZS)photocatalyst to fabricate a hierarchical CZS@CoO_(x) heterostructure.The unique hierarchical structure effectively accelerates the directional transfer of photogenerated charges,reducing charge recombination through the smooth interfacial heterojunction between CZS and CoO_(x),as evidenced by photoluminescence(PL)spectroscopy and various electrochemical characterizations.The surface cobalt species on the CZS material also act as efficient cocatalysts for photocatalytic hydrogen production,with activity even higher than that of noble metals.The well-defined CZS@CoO_(x) heterostructure not only enhances the interfacial separation of photoinduced charges,but also improves surface catalytic reactions.This leads to superior photocatalytic performances,with an apparent quantum efficiency of 20%at 420 nm for visible-light-driven hydrogen generation,which is one of the highest quantum efficiencies measured among noble-metal-free photocatalysts.Our work presents a potential pathway for controlling complex charge separation and catalytic reaction processes in photocatalysis,guiding the practical development of artificial photocatalysts for successful transformation of solar to chemical energy.

Incoherent Oscillations Accompanying Charge Separation in Photosynthetic Reaction Centers

Early events of charge separation in reaction centers (RCs) of bacterial photosynthesis are modeled by kinetic equations with time-dependent rate constants. An illustrative case of regular motion along a “slow” coordinates leading to oscillations in the kinetics is examined. Different schemes of charge separation are investigated. A good fitting of experimental kinetics of native Rba. sphaeroides RCs is achieved in the five states model P*1BAHA↔P*2BAHA↔I↔P+HA↔P+BA with two excited states BAHA and BAHA and three charge separated states I, P+HA and P+BA (P is a primary electron donor, bacteriochlorophyll dimer, BA and HA are an electron acceptor, monomeric bacteriochlorophyll and bacteriopheophytin in active A-branch, respectively). In the model only the first excited state is directly populated by optical excitation. The emission of the two excited states is assumed to be at 905 and 940 nm, respectively. The intermediate state I is assumed to absorb at 1020 nm as well as the P+HA state. The model explains the deep oscillations in the kinetics of the stimulated emission and of the absorption. In the simpler schemes without the I state or with only one excited state the accordance with the experiment is achieved at unreal parameter values. A possible nature of the I and BAHA states and a possible incoherent nature of the oscillations are discussed.

Separation of protactinium in the reaction of 60MeV/nucleon ^(18)O ions with natural uranium

The activities of protactinium were produced by the multi-nucleontransfer reactions in bombardment of the natural uranium with 60 MeV/nucleon 1sOions. A simple, relatively fast radiochemical procedure was used for extraction sep-aration of protactinium from the uranium and a variety of reaction products using1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. Theγ ray spectrum of the separated protactinium fractions showed that the protactiniumcould be separated from all of the main impurity elements. The decontaminationfactors of the uranium and the main reaction products produced in the reaction aregiven.

Mutual separation characteristics for binary oxides Y_2O_3-Ln_2O_3(Ln = Sc,La,Nd,Sm) using stepwise selective chlorination-chemical vapor transport reaction mediated by vapor complexes KLnCl_4

Mutual separation characteristics for binary oxide mixtures Y2O3-Sc2O3, Y2O3-La2O3, Y2O3-Nd2O3 and Y2O3-Sm2O3 using a stepwise selective chlorination-chemical vapor transport（SC-CVT） reaction mediated by vapor complexes KLnCl4 were investigated. The total transported yields of the chlorides produced from the oxide mixtures are in the order of NdCl3>SmCl3>LaCl3>YCl3>ScCl3, the main deposition temperature of the chlorides is in the order of ScCl3<YCl3<SmCl3<NdCl3<LaCl3, and the largest separation factor values are 1 100 for Y∶Sc, 14.88 for Y∶La, 9.86 for Y∶Nd and 16.45 for Y∶Sm in the temperature range from 1 000 K to )1 120 K,) while 157.7 for La∶Y, 51.6 for Nd∶Y and 12.4 for Sm∶Y in the temperature range from 1 200 K to 1 300 K, respectively. The results were discussed on the difference of KScCl4, KYCl4 and KLnCl4 and the selective chlorination of binary oxides at 800 K. Furthermore, the separation characteristics of vapor rare earth complex KLnCl4 were studied compared with those of LnAlnCl3n+3.

Converting an O-vacancy-rich oxide into a multifunctional separator modifier for long-lifespan lithium metal batteries

The lithium metal anode is hailed as the desired "holy grail" for the forthcoming generation of highenergy-density batteries,given its astounding theoretical capacity and low potential.Nonetheless,the formation and growth of dendrites seriously compromise battery life and safety.Herein,an yttriastabilized bismuth oxide(YSB) layer is fabricated on the polypropylene(PP) separator,where YSB reacts with Li anode in-situ in the cell to form a multi-component composite interlayer consisting of Li_(3)Bi,Li_(2)O,and Y_(2)O_(3).The interlayer can function not only as a redistributor to regulate Li^(+) distribution but also as an anion adsorber to increase the Li^(+) transference number from 0.37 to 0.79 for suppressing dendrite nucleation and growth.Consequently,compared with the cell with a baseline separator,those with modified separators exhibit prolonged lifespan in both Li/Li symmetrical cells and Li/Cu half-cells.Notably,the full cells coupled with ultrahigh-loading LiFePO_(4) display an excellent cycling performance of 1700 cycles with a high capacity retention of ~80% at 1 C,exhibiting great potential for practical applications.This work provides a feasible and effective new strategy for separator modification towards building a much-anticipated dendrite-free Li anode and realizing long-lifespan lithium metal batteries.

乳腺癌microRNA表达谱的初步研究

目的:探讨miRNA基因表达谱的筛选及其在乳腺癌发生发展中的作用。方法:收集8例患者的新鲜乳腺癌组织及配对癌旁组织,利用miRNA芯片对其进行实验分析,并采用realtime-PCR验证芯片结果的准确性,生物信息学分析其作用靶点。结果:通过SAM软件,相对癌周组织在乳腺癌组织中查出上调的miRNA基因3个,下调的miRNA基因23个。其中显著上调的为hsa-miR-155和hsa-miR-193b。显著下调的为hsa-miR-145,hsa-miR-381,hsa-miR-132,rno-miR-10b,hsa-miR-199b-5p,hsa-miR-100,hsa-miR-335,hsa-miR-497和hsa-miR-99a。实时定量验证芯片结果准确可靠,生物信息学发现不同miRNA对应的靶基因分别为FOXA1、HOXA1、SMAD7和PSTON等。结论:筛选得到乳腺癌miRNA的差异表达谱靶点非常广泛,涉及到细胞周期调控,转录调控等,可能在乳腺癌的发病机制中发挥潜在作用。

^(18)F-FMISO的自动化合成改进及其肿瘤乏氧Micro-PET/CT显像

1-H-1-(3-[18F]氟-2-羟基丙基)-2-硝基咪唑(18F-FMISO)是特异性肿瘤乏氧分子影像探针,其PET/CT显像指导肿瘤放疗靶区的勾画具有重要的临床应用价值。本文旨在建立18F-FMISO的改进的自动化合成方法,开展其肿瘤乏氧Micro-PET/CT显像研究。基于标记前体NITTP和简便的"一锅法",利用升级、改进的Explora GN模块,依次完成放射氟化反应(NITTP(10 mg),MeCN(1.0 mL),120 oC,5.0 min)、水解反应(HCl(1.0 mol/L,1.0 mL),130 oC,8.0 min)和HPLC分离纯化,自动化合成18F-FMISO。同时,采取分析型Radio-HPLC和Radio-TLC等方法检测各项质量控制指标,利用Micro-PET/CT进行荷SW1990胰腺肿瘤乏氧显像实验。结果表明,18F-FMISO的自动化生产时间约为65 min,放射化学产率为(30 5.0)%(未衰变校正,n=20),放射化学纯度大于99%,比活度为(2.04 0.17)×1011Bq·mol–1,化学纯度得到改善。Micro-PET/CT显像表明,18F-FMISO在荷SW1990瘤鼠体内均呈全身分布,最佳的肿瘤乏氧显像时间为注射后3.0 h,肿瘤/肌肉吸收比为3.00 0.08。本研究建立了基于HPLC分离纯化而改进的18F-FMISO的自动化合成方法,而且其Micro-PET/CT肿瘤乏氧显像对比度高,为乏氧显像研究提供了可靠的制备方法和基本的实验参考依据。

隧道超挖超耗管控措施研究

隧道的超挖超耗管控是绿色低碳时代背景下工程界最关心的难题,对施工企业的成本控制和效益提升具有重要意义。以武两高速XFS隧道为背景,系统总结了隧道超挖超耗的10类影响因素和常见对策,包括围岩条件、施工参数、测量放样、爆破方案、钻孔质量、喷射混凝土回弹率、预留变形量、物资设备性能、作业人员水平和现场施工管控。分析了XFS隧道超挖超耗的原因,并制定了加强地质预报和超前支护施作,减小开挖进尺;动态调整爆破方案,严格炮孔质量检查;引入超细改性硅微粉优化配合比,提高喷射工艺水平;加强现场施工管控,制定超挖超耗管控办法,落实作业人员的激励奖惩等措施。措施执行后,XFS隧道平均超挖由30.1 cm降低至16.6 cm,综合超耗由173.7%降低至100.7%。

Micro–meso-macroporous FeCo-N-C derived from hierarchical bimetallic FeCo-ZIFs as cathode catalysts for enhanced Li-O2 batteries performance

Developing bifunctional catalysts that increase both the OER and ORR kinetics and transport reactants with high efficiency is desirable. Herein, micro–meso-macroporous FeCo-N-C-X(denoted as "MFeCo-N-C-X", X represents Fe/Co molar ratio in bimetallic zeolite imidazole frameworks FeCo-ZIFs) catalysts derived from hierarchical M-FeCo-ZIFs-X was prepared. The micropores in M-FeCo-N-C-X have strong capability in O2 capture as well as dictate the nucleation and early-stage deposition of Li2O2,the mesopores provided a channel for the electrolyte wetting, and the macroporous structure promoted more available active sites when used as cathode for Li-O2 batteries. More importantly, M-Fe CoN-C-0.2 based cathode showed a high initial capacity(18,750 mAh g-1@0.1 A g-1), good rate capability(7900 m Ah g-1@0.5 A g-1), and cycle stability up to 192 cycles. Interestingly, the FeCo-N-C-0.2 without macropores suffered relatively poorer stability with only 75 cycles, although its discharge capacity was still as high as 17,200 mA h g-1(@0.1 A g-1). The excellent performance attributed to the synergistic contribution of homogeneous Fe, Co nanoparticles and N co-doping carbon frameworks with special micro–meso-macroporous structure. The results showed that hierarchical FeCo-N-C architectures are promising cathode catalysts for Li-O2 batteries.

A p-n WO_(3)/SnSe_(2) Heterojunction for Efficient Photo-assisted Electrocatalysis of the Oxygen Evolution Reaction

Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnSe_(2)(WS)heterojunction significantly activates OER catalysis of CoFe-layered double hydroxide(CF)/carbon nanotubes(CNTs).Specifically,the catalyst achieves an overpotential of 224 mV at 10 mA cm^(-2)and a small Tafel slope of 47 mV dec^(-1),superior to RuO_(2)and most previously reported transition metal-based OER catalysts.The p-n WS heterojunction shows strong light absorption to produce photogenerated carriers.The photogenerated holes are trapped by CF to suppresses the charge recombination and facilitate charge transfer,which accelerates OER kinetics and boost the activity for the OER.This work highlights the possibility of using heterojunctions to activate OER catalysis and advances the design of energy-efficient catalysts for water oxidation systems using solar energy.

Altered microRNA expression profiles in a rat model of spina bifida

Micro RNAs（mi RNAs） are dynamically regulated during neurodevelopment,yet few reports have examined their role in spina bifida.In this study,we used an established fetal rat model of spina bifida induced by intragastrically administering olive oil-containing all-trans retinoic acid to dams on day 10 of pregnancy.Dams that received intragastric administration of all-trans retinoic acid-free olive oil served as controls.The mi RNA expression profile in the amniotic fluid of rats at 20 days of pregnancy was analyzed using an mi RNA microarray assay.Compared with that in control fetuses,the expression of mi RNA-9,mi RNA-124 a,and mi RNA-138 was significantly decreased（〉 2-fold）,whereas the expression of mi RNA-134 was significantly increased（〉 4-fold） in the amniotic fluid of rats with fetuses modeling spina bifida.These results were validated using real-time quantitative reverse-transcription polymerase chain reaction.Hierarchical clustering analysis of the microarray data showed that these differentially expressed mi RNAs could distinguish fetuses modeling spina bifida from control fetuses.Our bioinformatics analysis suggested that these differentially expressed mi RNAs were associated with many cytological pathways,including a nervous system development signaling pathway.These findings indicate that further studies are warranted examining the role of mi RNAs through their regulation of a variety of cell functional pathways in the pathogenesis of spina bifida.Such studies may provide novel targets for the early diagnosis and treatment of spina bifida.

Flow control of micro-ramps on supersonic forward-facing step flow

The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step（FFS） was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering（NPLS）and particle image velocimetry（PIV） techniques. High spatiotemporal resolution images and velocity fields of supersonic flow over the testing model were captured. The fine structures and their spatial evolutionary characteristics without and with the micro-ramps were revealed and compared. The large-scale structures generated by the micro-ramps can survive the downstream FFS flowfield. The micro-ramps control on the flow separation and the separation shock unsteadiness was investigated by PIV results. With the micro-ramps, the reduction in the range of the reversal flow zone in streamwise direction is 50% and the turbulence intensity is also reduced. Moreover, the reduction in the average separated region and in separation shock unsteadiness are 47% and 26%, respectively. The results indicate that the micro-ramps are effective in reducing the flow separation and the separation shock unsteadiness.

Improved catalytic performance of Ni catalysts for steam methane reforming in a micro-channel reactor

Milliseconds process to produce hydrogen by steam methane reforming （SMR） reaction, based on Ni catalyst rather than noble catalyst such as Pd, Rh or Ru, in micro-channel reactors has been paid more and more attentions in recent years. This work aimed to further improve the catalytic performance of nickel-based catalyst by the introduction of additives, i.e., MgO and FeO, prepared by impregnation method on the micro-channels made of metal-ceramic complex substrate. The prepared catalysts were tested in the same micro-channel reactor by switching the catalyst plates. The results showed that among the tested catalysts Ni-Mg catalyst had the highest activity, especially under harsh conditions, i.e., at high space velocity and/or low reaction temperature. Moreover, the catalyst activity and selectivity were stable during the 12 h on stream test even when the ratio of steam to carbon （SIC） was as low as 1.0. The addition of MgO promoted the active Ni species to have a good dispersion on the substrate, leading to a better catalytic performance for SMR reaction.

Structure Characterization and Dephosphorization Effect Analysis of Oyster Shell-silica Micropowder Waste Water Dephosphorization Materials

In this work,the effects of pH value of waste water and initial concentration of phosphorus on dephosphorization materials were investigated.The materials were prepared by shaping,sintering and hydrothermal reshaping oyster shell and silica micro-powder.Different concentrations of phosphorus-contained waste water were simulated with potassium dihydrogen phosphate solution,the effect of dephosphorization was tested with phosphomolybdenum blue spectrophotometer method,and the crystal phase and microstructure of materials were characterized by XRD and SEM methods. It was indicated that dephosphorization was completed in 6 h when the initial phosphorus concentration in waste water was lower than 15 mg/L, and the dephosphorization time prolonged as the increase of phosphorus concentration. It was observed that the pH value of waste water influenced dephosphorization significantly, and neutral subalkalic environment favored dephosphorization. When the pH value was 11, the efficiency of dephosphozation was the greatest. For waste water with an initial concentration of 20 mg/L, the dephosphozation rate is close to 100% in8 h.

Hydrogen etching induced hierarchical meso/micro-pore structure with increased active density to boost ORR performance of Fe-N-C catalyst

Rational regulation on pore structure and active site density plays critical roles in enhancing the performance of Fe-N-C catalysts. As the microporous structure of the carbon substrate is generally regarded as the active site hosts, its hostility to electron/mass transfer could lead to the incomplete fulfillment of the catalytic activity. Besides, the formation of inactive metallic Fe particles during the conventional catalyst synthesis could also decrease the active site density and complicate the identification of real active site. Herein, we developed a facial hydrogen etching methodology to yield single site Fe-N-C catalysts featured with micro/mesoporous hierarchical structure. The hydrogen concentration in pyrolysis process was designated to effectively regulate the pore structure and active site density of the resulted catalysts.The optimized sample achieves excellent ORR catalytic performance with an ultralow H2O2 yield(1%)and superb stability over 10,000 cycles. Our finding provides new thoughts for the rational design of hierarchically porous carbon-based materials and highly promising non-precious metal ORR catalysts.