Appreciable Enhancement of Photocatalytic Performance for N-doped SrMoO_(4) via the Vapor-thermal Method

A series of nitrogen-doped SrMoO_(4) with different Sr/N mole ratio (R=0,0.05,0.10,0.15,0.20,0.40,and 0.60) were synthesized using urea as the N source via the vapor-thermal method.The photocatalytic degradation ability of all samples was evaluated using methylene blue (MB) as a target contaminant.The band gaps of N-doped samples are all higher than that of pristine ones,which is only 3.12 eV.BET specific surface area S_(BET) and pore volume are increased due to the N doping.And the greater increase of S_(BET),the faster the photodegradation speed of methylene blue on SrMoO_(4).More specifically,the degradation efficiency of MB is improved up to 87%in 100 min.

Rare-earth element geochemistry reveals the provenance of sediments on the southwestern margin of the Challenger Deep

The hadal zone represents one of the last great frontiers in modern marine science,and deciphering the provenance of sediment that is supplied to these trench settings remains a largely unanswered question.Here,we examine the mineralogical and geochemical composition of a sediment core(core CD-1)that was recovered from the southwestern margin of the Challenger Deep within the Mariana Trench.Major element abundances and rare-earth element patterns from these sediments require inputs from both terrigenous dust and locally sourced volcanic debris.We exploit a two-endmember mixing model to demonstrate that locally sourced volcanic material dominates the sediment supply to the Challenger Deep(averaging^72%).The remainder,however,is supplied by aeolian dust(averaging^28%),which is consistent with adjacent studies that utilized Sr-Nd isotopic data.Building on a growing database,we strengthen our understanding of Asian aeolian dust input into the northwestern Pacific,which ultimately improves our appreciation of sedimentation in,and around,the hadal zone.

Geochemical characteristics and their significances of rare-earth elements in deep-water well core at the Lingnan Low Uplift Area of the Qiongdongnan Basin

A geochemical analysis of rare-earth elements （REEs） in 97 samples collected from the core of deep-water Well LS-A located at the Lingnan Low Uplift Area of the Qiongdongnan Basin is conducted, with the pur-pose of revealing the changes of sedimentary source and environment in the study region since Oligocene and evaluating the response of geochemical characteristics of REEs to the tectonic evolution. In the core samples, both∑REE and∑LREE （LREE is short for light-group REEs） fluctuate in a relatively wide range, while∑HREE （HREE is short for heavy-group REEs） maintains a relatively stable level. With the stratigraphic chronology becoming newer, both∑REE and∑LREE show a gradually rising trend overall. The∑REE of the core is relatively high from the bottom of Yacheng Formation （at a well depth of 4 207 m） to the top of Ledong Formation, and the REEs show partitioning characteristics of the enrichment of LREE, the stable content of HREE, and the negative anomaly of Eu to varying degrees. Overall the geochemical characteristics of REEs are relatively approximate to those of China＇s neritic sediments and loess, with significant ＂continental ori-entation＂. The∑REE of the core is relatively low in the lower part of Yacheng Formation （at a well depth of 4 207-4 330 m）, as shown by the REEs partitioning characteristics of the depletion of LREE, the relative enrich-ment of HREE, and the positive anomaly of Eu; the geochemical characteristics of REEs are approximate to those of oceanic crust and basalt overall, indicating that the provenance is primarily composed of volcanic eruption matters. As shown by the analyses based on sequence stratigraphy and mineralogy, the provenance in study region in the early Oligocene mainly resulted from the volcanic materials of the peripheral uplift ar-eas; the continental margin materials from the north contributed only insignificantly; the provenance devel-oped to a certain extent in the late Oligocene. Since the Miocene, the provenance has ceaselessly expanded from proximal to distal realm, embodying a characteristic of multi-source sedimentation. In the core strata with 31.5, 28.4, 25.5, 23, and 16 Ma from today, the geochemical parameters of REEs and Th/Sc ratio have significant saltation, embodying the tectonic movement events in the evolution of the Qiongdongnan Basin. In the tectonic evolution history of the South China Sea, the South China Sea Movement （34-25 Ma BP, early expansion of the South China Sea）, Baiyun Movement （23 Ma BP）, late expansion movement （23.5-16.5 Ma BP）, expansion-settlement transition, and other important events are all clearly recorded by the geochemi-cal characteristics of REEs in the core.

Rare-earth and trace elements and hydrogen and oxygen isotopic compositions of Cretaceous kaolinitic sediments from the Lower Benue Trough, Nigeria: provenance and paleoclimatic significance

This study evaluated the Cretaceous(Campanian–Maastrichtian) kaolinitic sediments of the Ajali/Mamu and Enugu/Nkporo Formations from the Lower Benue Trough of Nigeria. A combined method of inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry was used to investigate trace and rareearth element geochemistry and hydrogen and oxygen isotopic compositions. These data were then used to infer the sediments' provenance and paleoclimatic conditions during their deposition. The sediments contained low concentrations of most trace elements, with the exceptions of Zr(651–1352 ppm), Ba(56–157 ppm), V(38–90 ppm),and Sr(15.1–59.6 ppm). Average values of Co and Ni were1.5 and 0.7 ppm, respectively. Trace and rare earth element values were lower than corresponding values for upper continental crust and Post-Archean Australian Shale, with the exception of Zr. The samples showed only slight light rare-earth enrichment and nearly flat heavy rare-earth depletion patterns, with negative Eu and Tm anomalies,typical of felsic sources. Geochemical parameters such as La/Sc, Th/Sc, and Th/Co ratios support that the kaolinitic sediments were derived from a felsic rock source, likely deposited in an oxic environment.^(18 )O values ranged from+ 15.4 to + 21.2% for the investigated samples, consistent with a residual material derived from chemicalweathering of felsic rock and redeposited in a sedimentary basin(typical values of + 19 to + 21.2%). While in the basin, the sediments experienced extended interactions with meteoric water enriched in d D and d16 O. However,the variation in d D and d16 O values for the investigated samples is attributed to the high temperature of formation(54–91 °C). The d D and d^(18 )O values suggest that the sediments, although obtained from different localities within the Lower Benue Trough, formed under similar hot,tropical climatic conditions.

Mechanism of interaction relation between the rare-earth element Ce and impurity elements Pb and Bi in Ag-based filler metal

The mechanism of interaction relation between the rare-earth element Ce and elements Pb and Bi in Ag-based filler metal has been studied. The results show that the compounds CePb and CeBi with high melting point can be easily produced between these three elements in the filler metal, which greatly limited the formation of the isolated phase Pb or Bi and also eliminated the bad effect of impurity elements Pb and Bi on the spreading property of Ag-based filler metal. The metallurgical and quantum-mechanical bond formation analysis show that a strong chemical affinity was existed between the rare-earth element Ce and impurity elements Pb and Bi, which was proved by the XRD analysis results.

Effects of rare-earth elements on the glass-forming ability and mechanical properties of Cu_(46)Zr_(47-x)Al_7M_x(M = Ce,Pr,Tb,and Gd) bulk metallic glasses

Cu46Zr47-xA17Mx （M = Ce, Pr, Tb, and Gd） bulk metallic glassy （BMG） alloys were prepared by copper-mold vacuum suction casting. The effects of rare-earth elements on the glass-forming ability （GFA）, thermal stability, and mechanical properties of Cu46Zr47-xA17Mx were investigated. The GFA of Cu46Zr47-xA17Mx （M = Ce, Pr） alloys is dependent on the content of Ce and Pr, and the optimal content is 4 at.%. Cu46Zr47-xA17Thx（X = 2, 4, and 5） amorphous alloys with a diameter of 5 mm can be prepared. The GFA of Cu46Zr47-xA17Gdx（x = 2, 4, and 5） increases with increasing Gd. Tx and Tp of all decrease. Tg is dependent on the rare-earth element and its content. ATx for most of these alloys decreases except the Cu46Zra2Al7Gd5 alloy. The activation energies △Eg, △Ex, and △Ep for the Cu46Zr42A17Gd5 BMG alloy with Kissinger equations are 340.7, 211.3, and 211.3 kJ/mol, respectively. These values with Ozawa equations are 334.8, 210.3, and 210.3 kJ/mol, respec- tively. The Cu46Zr45Al7Tb2 alloy presents the highest microhardness, Hv 590, while the Cu46Zr43A17Pr4 alloy presents the least, Hv 479. The compressive strength （at.f.） of the Cu46Zra3A17Gd4 BMG alloy is higher than that of the Cu46Zr43Al7Tb4 BMG alloy.

Influence of rare-earth metal doping on the catalytic performance of CuO-CeO_2 for the preferential oxidation of CO in excess hydrogen

Doping of different rare-earth metals （Pr, Nd, Y and La） had an evident influence on the catalytic performance of CuO-CeO2 for the preferential oxidation （PROX） of CO in excess hydrogen. As for Pr, the doping enhanced the catalytic activity of CuO-CeO2 for PROX. For example, the CO conversion over the above catalyst for PROX was higher than 99% at 120 °C. Especially, the doping of Pr widened the temperature window by 20 °C over CuO-CeO2 with 99% CO conversion. For Nd, Y, and La, the doping depressed the catalytic activity of CuO-CeO2 for PROX. However, the doping of transition metals markedly improved the selectivity of CuO-CeO2 for PROX.

A Review on Zinc Sulphide Thin Film Fabrication for Various Applications Based on Doping Elements

Zinc Sulfide (ZnS) thin film has attracted increasing attention due to their potential applications in the new generation of nano-electronics and opto-electronics devices. The physical and chemical properties of ZnS have outstanding quality for different applications. Moreover, ZnS doped with various elements are creating a new era for both academic research and industrial applications. So, the optical properties of modified ZnS thin film will help us to find a suitable doping element for convenient deposition which may enhance the conductance and transmitting properties of the film. This review work has been carried out to explore the four-modification elements that constitute Cu, Ni, Co & Fe as descending order of atomic number corresponding to Zn, along with some potential applications considering the recent research work with other doping elements too such as Al, C, Pt etc. For example, FE, FET, Catalytic, Solar cell, Electroluminescence, Fuel cell, different sensors (Chemical sensors, Bio-sensors, Humidity sensors, light sensors, UV light sensors) and nanogenerators use ZnS thin film.

Microstructure and finite element analysis of hot continuous rolling of doped tungsten rod

The microstructures of doped tungsten deformed by multi-pass hot continuous rolling were investigated, and the stress and strain fields were simulated by finite element(FE) method. After the continuous rolling, the grains of the tungsten rod were refined, and the microhardness was improved; however, a ring region of abnormal grain growth was present at a distance of about 3/5 R(R is the radius of the rod) from the center of the cross section. FE modeling results showed that the equivalent residual strains were minimum around the region of abnormal grain growth; this was due to the release of strain energy by severe plastic deformation, leading a situation where the migration force of grain boundaries was higher than the pinning force of potassium bubbles. By decreasing the initial rolling temperature and rolling speeds, the inhomogeneity of the equivalent residual stain decreased, improving the microstructure uniformity of the doped tungsten.

Influence of Doped Elements on Electrochemical High Temperature Performance of La-riched Hydrogen Storage Material

The effects of small amounts of added elements such as aluminum, titanium and zirconium to MlNi 3.8(CoMn) 1.2 on its electrochemical performances and performances at high temperatures were investigated.It is found that the addition of aluminum brings about a significant increase in the discharge capacity at high temperatures,and the capacity decay during repeated charge-discharge cycles and the self-discharge are both suppressed, while the rate capability decreases.The alloy containing zirconium exhibits a longer cycle life and a better rate capability,but a much lower discharge capacity.The addition of titanium improves the rate capability, but the capacity decreases greatly.An X-ray diffraction analysis indicates that a second phase exists in the alloy with additive Zr or Ti,which improves the discharge-rate characteristics,and the superior stability of the alloy with additive Al may be due to the expansion of lattice parameters and cell volume.

INFLUENCE OF RARE-EARTH ELEMENTS ON THERMAL STABILITY OF PdSi_(16.5)GLASS

The influence of rare-earth elements,La,Ce,Pr,Nd,Sm,Eu,Gd,Dy,Ho,Er and Yb on the thermal stability of PdSi_(16.5) glass was studied systematically by means of DSC.All rare-earth elements,especially heavy ones,increase obviously the thermal stability parameters,including T_θ(T_g ,T_x ,T_g),T_(rg) and ΔE etc.The crystallization temperatures T_(p1) and T_(p2) increase linearly with the lanthanide constriction increasing,but Eu shows an anomalous influence:Pd-Si-Eu metallic glass possesses the highest thermal stability and the lowest concentration limit of glass forming among Pd-Si-R glasses.

Influence of Rare-Earth Elements on ElectricalProperties of Pd

The influence of RE (RE = La, Ce. Pr. Nd, Sm, Eu, Gd. Tb. Dy, Er, Yb) additives with dilute concentrations on the electrical properties of Pd has been studied. All RE elements increase the specific resistivity (ρ) and decrease the resistance temperature coefficient (α) of Pd. and (ρ.α) Pd-RE ls equal to (ρ· α)Pd.The RE elements before Gd reduce the thermo-emf of Pd on Cu. other heavy RE enhance the thermo-emf.The experimental data of normalized Pd-0.1 at.-%RE alloys indicate that the effect of light RE additives on the specific resistivity of Pd is larger than that of heavy RE and Ce. Eu and Yb show anomalous strong effect. The valence and atomic size are main factors influencing the electrical properties.

Optical Fiber Torsion Sensor with Mechanically Induced Long Period Fiber Gratings in Rare-Earth Doped Fibers

In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mechanical analysis for both types of fibers under different torsion conditions is presented. In order to apply the torsion one of the fiber ends is fixed while torsion is applied on the other end. A MLPFG whose period is 503 μm is used to press the fiber after torsion is applied. This allows for micro curvatures to be formed on the fiber, which in turn generates a periodical index perturbation on it. Here, it was noted that the sensitive wavelength shift of the rejection bands is bigger for Er-doped fibers. For a torsion of 6 turns applied to 10 cm of doped fiber the wavelength peaks can be moved up to 25 nm, which is longer to what was detected on standard fibers. Therefore, by using Er-doped fibers to monitor torsion on structures will give more sensitive and accurate results than using standard fibers. These results can be employed for sensing applications, especially for small to medium size structures, which can be mechanical, civil or aeronautics.

Microscale Crystalline Rare-Earth Doped Resonators for Strain-Coupled Optomechanics

Rare-earth ion doped crystals for hybrid quantum technologies are an area of growing interest in the solid-state physics community. We have earlier theoretically proposed a hybrid scheme of a mechanical resonator which is fabricated out of a rare-earth doped mono-crystalline structure. The rare-earth ion dopants have absorption energies which are sensitive to crystal strain, and it is thus possible to couple the ions to the bending motion of the crystal cantilever. This type of resonator can be useful for either investigating the laws of quantum physics with material objects or for applications such as sensitive force-sensors. Here, we present the design and fabrication method based on focused-ion-beam etching techniques which we have successfully employed in order to create such microscale resonators, as well as the design of the environment which will allow studying the quantum behavior of the resonators.

Infrared emissivity of transition elements doped ZnO

Infrared emissivity was studied in Zn0.99M0.01O(M is Mn,Fe or Ni) and Zn1-xCoxO(x=0.01,0.02,0.03 and 0.04) powders synthesized by solid-state reaction at various temperatures.XRD patterns confirm the wurtzite structure of the prepared samples.No peaks of other phases arising from impurities are detected in Mn-and Co-doped ZnO,but the peaks of ZnFe2O4 and NiO are observed in Zn0.99Fe0.01O and Zn 0.99 Ni 0.01 O.The SEM observations indicate that with larger grain sizes than those of Zn0.99Fe0.01O and Zn0.99Ni0.01O,Co-doped ZnO exhibits smooth grain surfaces.The infrared absorption spectra show that infrared absorptions related to oxygen in Zn0.99M0.01O are much stronger than those in Co-doped ZnO.Co ions are dissolved into the ZnO lattice with Co2+ state from XPS spectra analysis.The infrared emissivity results imply that the emissivity of Zn0.99Ni0.01 O is the highest(0.829) and that of Zn 0.99 Co 0.01 O is the lowest(0.784) at 1 200 C.The emissivity of Zn0.99Co0.01O decreases to the minimum(0.752) at 1 150 C and then increases with growing calcination temperature.As the Co doping content grows,the emissivity of Co-doped ZnO calcined at 1 200 C falls to 0.758 in the molar fraction of 3% and then ascends.

氮化碳改性材料在光催化降解抗生素中的应用

作为具有可诱发菌群抗药性等特殊生态效应的典型新污染物,抗生素的去除技术近年来备受关注。然而传统的水处理方法很难有效去除水中的微量抗生素,对生态环境、饮用水安全造成了威胁。光催化技术因具有反应条件温和、成本低、降解效率高且去除彻底等优势在抗生素的降解方面具有广泛的应用前景。氮化碳(CN)材料作为一种具有可见光响应的非金属光催化剂一直是光催化领域的研究热点。然而,纯CN存在太阳光吸收不足、表面积小和光生电子空穴对快速复合等问题,导致光催化活性低。通过元素掺杂和与其他材料形成异质结等改性策略可以有效改善CN的光催化性能,增强材料的光吸收,促进光生载流子的分离和传输。本文综述了CN改性光催化剂在其设计、光生载流子分离/转移机制及在抗生素光催化降解方面的重要进展,总结和展望了开发先进CN改性光催化剂的方向。

二硫化钼自润滑涂层性能及制备工艺的研究进展

MoS_(2)是过渡族金属二硫化物中的一员,其涂层材料因独特的层状结构而表现出优异的摩擦学性能。MoS_(2)自润滑涂层在刀具以及空间部件材料的表面减磨和保护上发挥着重要作用,但是MoS_(2)涂层对湿度的敏感性、附着力差以及耐磨寿命有限等问题限制了其应用。国内外学者在MoS_(2)涂层的摩擦学研究上做了大量工作,目前的研究重点主要是不同温度、湿度、气体介质的多环境下的摩擦学行为分析,以及通过纳米多层体系的设计实现对晶体结构的可控。本文概述了2010年以来有关MoS_(2)自润滑涂层材料的研究进展,主要综述了MoS_(2)自润滑涂层的摩擦学性能以及不同元素掺杂对其性能和结构的影响。总结了MoS_(2)涂层的组成结构、性能、制备工艺,并对其在表面润滑领域的研究和应用前景进行了展望。本文对MoS_(2)自润滑涂层的研究和工程应用具有参考意义。

碳酸氧铋基光催化材料的改性研究进展

碳酸氧铋是一种典型的铋基半导体光催化材料,其具有[BiO]_(2)^(+2)和CO_(3)^(2-)层交替组成的独特层状晶体结构。通过改性可促进(BiO)_(2)CO_(3)的可见光响应能力以及光生电荷分离效率,从而提升其光催化性能。本文主要从贵金属沉积、元素掺杂、异质结构建以及氧空位缺陷等方面综述了碳酸氧铋基光催化材料的改性研究进展。同时指出碳酸氧铋的改性研究需致力于进一步简化制备工艺,并使得改性工艺控制更加精准,以使其在有机污染物降解、光解水制氢等方面得到更好的应用前景。

Al掺杂硫铟锌光催化剂的制备综合实验教学设计与实践

结合化学工程与工艺专业人才培养方案和实践教学体系的要求,设计了硫铟锌(ZnIn2S4)基光催化剂的制备综合性实验。实验采用溶剂热法制备了Al掺杂硫铟锌光催化剂,系统地表征分析了光催化剂的晶体结构、形貌以及光电化学特性。该实验是将典型的科研成果转化为实验教学内容,有助于学生了解该领域的前沿科学成果和研究方法,掌握光催化剂的制备技术,进而深入理解光电化学性能相关专业理论知识。科研反哺教学有利于创新实验教学内容,激发和培养学生的创新意识和专业综合实践能力。

稀土掺杂上转换纳米材料在金属离子检测领域中的应用

重点综述了基于稀土掺杂上转换纳米材料(REEs-UCNPs)构建荧光共振能量转移(FRET)体系或发光共振能量转移(LRET)体系来实现对金属离子定量分析检测的研究进展,并对REEs-UCNPs在生物医学、卫生分析和环境检测等领域应用的未来发展趋势进行了展望。