The hard X-ray nanoprobe beamline at the SSRF

The hard X-ray nanoprobe beamline BL13U is a phase-Ⅱ beamline project at the Shanghai Synchrotron Radiation Facility.The beamline aims to enable comprehensive experiments at high spatial resolutions ranging from 50 to 10 nm. The X-ray energy range of the beamline, 5–25 keV, can detect most elements in the periodic table. Two operating modes were designed to accommodate the experimental requirements of high-energy resolution or high photon flux, respectively. X-ray nanofluorescence, nanodiffraction, and coherent diffraction imaging are developed as the main experimental techniques for BL13U. This paper describes the beamline optics, end station configurations, experimental methods under development, and preliminary test results. This comprehensive overview aims to provide a clear understanding of the beamline capabilities and potential applications.

Study on the hydrogen absorption properties of a YGdTbDyHo rare-earth high-entropy alloy

This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),YGdTbDyHo.Results indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with the alloy elements distributed homogeneously.Upon hydrogen absorption,the phase structure of the HEA changed from a solid solution with an hexagonal-close-packed(HCP)structure to a high-entropy hydride with an faced-centered-cubic(FCC)structure without any secondary phase precipitated.The alloy demonstrated a maximum hydrogen storage capacity of 2.33 H/M(hydrogen atom/metal atom)at 723 K,with an enthalpy change(ΔH)of-141.09 kJ·mol^(-1)and an entropy change(ΔS)of-119.14 J·mol^(-1)·K^(-1).The kinetic mechanism of hydrogen absorption was hydride nucleation and growth,with an apparent activation energy(E_(a))of 20.90 kJ·mol^(-1).Without any activation,the YGdTbDyHo alloy could absorb hydrogen quickly(180 s at 923 K)with nearly no incubation period observed.The reason for the obtained value of 2.33 H/M was that the hydrogen atoms occupied both tetrahedral and octahedral interstices.These results demonstrate the potential application of HEAs as a high-capacity hydrogen storage material with a large H/M ratio,which can be used in the deuterium storage field.

Controllable Synthesis of Fluorescent Carbon Dots and Their Detection Application as Nanoprobes

Carbon dots(CDs), as a new member of carbon nanomaterial family, have aroused great interest since their discovery in 2004. Because of their outstanding water solubility, high sensitivity and selectivity to target analytes, low toxicity, favorable biocompatibility, and excellent photostability, researchers from diverse disciplines have come together to further develop the fundamental properties of CDs. Many methods for the production of CDs have been reported, therein, hydrothermal and solvothermal technology needs simple equipments, and microwave synthesis needs less reaction time, hence these methods become current common synthesis methods, in which many precursors have been applied to produce CDs. Due to their excellent fluorescence, CDs have made impressive strides in sensitivity and selectivity to a diverse array of salt ions,organic/biological molecules and target gases. The development of CDs as nanoprobes is still in its infancy, but continued progress may lead to their integration into environmental and biological applications. Hydrothermal,solvothermal, and microwave synthesis of fluorescent carbon dots and their detection applications as nanoprobes in salt ions, organic/biological molecules, and target gases will be reviewed.

Specific Recognition of Breast Cancer Cells In Vitro Using Near Infrared-Emitting Long-Persistence Luminescent Zn_3Ga_2Ge_2O_(10):Cr^(3+)Nanoprobes

In this paper, near-infrared emitting long-persistence luminescent Zn3Ga2Ge2O10:Cr3?(ZGG) nanoparticles with diameters of 30–100 nm and bright luminescence were prepared by a sol–gel synthesis method. After the surface amination, the nanoparticles were further bioconjugated with breast cancer-specific monoclonal antibody(anti-Ep CAM) to form ZGG-Ep CAM nanoprobes which can specifically target breast cancer cell lines(MCF7) in vitro. The results of in vitro images show that the luminescence signals from the cells treated with ZGG-Ep CAM nanoprobes are stronger than those from cells treated with ZGG-unconjugated antibody, indicating that the prepared ZGG-Ep CAM nanoprobes possessed excellent specific recognition capability. Furthermore, due to their long afterglow properties, the imaging could persist more than 1 h. Therefore, these nanoprobes could not only provide a high specificity detection method for cancer cells but also realize the long-time monitoring. Developed near-infrared emitting long-persistence luminescent nanoprobes will be expected to find new perspectives for cell therapy research and diagnosis applications.

Human iPS Cells Loaded with MnO2-Based Nanoprobes for Photodynamic and Simultaneous Enhanced Immunotherapy Against Cancer

How to trigger strong anti-tumor immune responses has become a focus for tumor therapy.Here,we report the human-induced pluripotent stem cells(iPSs)to deliver MnO2@Ce6 nanoprobes into tumors for simultaneous photodynamic therapy(PDT)and enhanced immunotherapy.Ce6 photosensitizer was attached on manganese dioxide(MnO2)nanoparticles,and resultant MnO2@Ce6 nanoprobes were delivered into mitomycin-treated iPSs to form iPS-MnO2@Ce6 nanoprobes.The iPS-MnO2@Ce6 actively targeted in vivo tumors,the acidic microenvironment triggered interaction between MnO2 and H2O2,released large quantities of oxygen,alleviated hypoxia in tumor.Upon PDT,singlet oxygen formed,broken iPSs released tumor-shared antigens,which evoked an intensive innate and adaptive immune response against the tumor,improving dendritic cells matured,effector T cells,and natural killer cells were activated.Meanwhile,regulatory T cells were reduced,and then the immune response induced by iPS-MnO2@Ce6 was markedly stronger than the immune reaction induced by MnO2@Ce6(P<0.05).The iPS-MnO2@Ce6 markedly inhibited tumor growth and metastasis and reduced mortality in mice models with tumor.Human iPS s loaded with MnO2-based nanoprobes are a promising strategy for simultaneous PDT and enhanced immunotherapy against tumor and own clinical translational prospect.

Iron-Imprinted Single-Atomic Site Catalyst-Based Nanoprobe for Detection of Hydrogen Peroxide in Living Cells

Fe-based single-atomic site catalysts(SASCs),with the natural metalloproteases-like active site structure,have attracted widespread attention in biocatalysis and biosensing.Precisely,controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs’performance.In this work,we use a facile ion-imprinting method(IIM)to synthesize isolated Fe-N-C single-atomic site catalysts(IIM-Fe-SASC).With this method,the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites.The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references.Due to its excellent properties,IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide(H_(2)O_(2)).Using IIM-Fe-SASC as the nanoprobe,in situ detection of H_(2)O_(2)generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity.This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H_(2)O_(2)detection.

Electrical characterization of an individual nanowire using flexible nanoprobes fabricated by atomic force microscopy-based manipulation

Nanowires have emerged as promising one-dimensional materials with which to construct various nanocircuits and nanosensors.However,measuring the electrical properties of individual nanowires directly remains challenging because of their small size,thereby hindering the comprehensive understanding of nanowire-based device performance.A crucial factor in achieving reliable electrical characterization is establishing well-determined contact conditions between the nanowire sample and the electrodes,which becomes particularly difficult for soft nanowires.Introduced here is a novel technique for measuring the conductivity of an individual nanowire with the aid of automated nanomanipulation using an atomic force microscope.In this method,two nanowire segments cut from the same silver nanowire are positioned onto a pair of gold electrodes,serving as flexible nanoprobes to establish controllable contact with the sample.By changing the contact points along the nanowire sample,conductivity measurements can be performed on different regions,thereby eliminating the influence of contact resistance by analyzing multiple current–voltage curves.Using this approach,the resistivity of a 100-nm-diameter silver nanowire is determined to be 3.49×10^(−8)Ωm.

Critical current degradation in an epoxy-impregnated rare-earth Ba_(2)Cu_(3)O_(7-x)coated conductor caused by damage during a quench

High-temperature superconducting(HTS)rare-earth Ba_(2)Cu_(3)O_(7-x)(REBCO)coated conductors(CCs)have significant potential in high-current and high-field applications.However,owing to the weak interface strength of the laminated composite REBCO CCs,the damage induced by the thermal mismatch stress under a combination of epoxy impregnation,cooling,and quenching can cause premature degradation of the critical current.In this study,a three-dimensional(3D)electromagnetic-thermal-mechanical model based on the H-formulation and cohesive zone model(CZM)is developed to study the critical current degradation characteristics in an epoxy-impregnated REBCO CC caused by the damage during a quench.The temperature variation,critical current degradation of the REBCO CC,and its degradation onset temperature calculated by the numerical model are in agreement with the experimental data taken from the literature.The delamination of the REBCO CC predicted by the numerical model is consistent with the experimental result.The numerical results also indicate that the shear stress is the main contributor to the damage propagation inside the REBCO CC.The premature degradation of the critical current during a quench is closely related to the interface shear strength inside the REBCO CC.Finally,the effects of the coefficient of thermal expansion(CTE)of the epoxy resin,thickness of the substrate,and substrate material on the critical current degradation characteristics of the epoxy-impregnated REBCO CC during a quench are also discussed.These results help us understand the relationship between the current-carrying degradation and damage in the HTS applications.

Leaching behaviors of iron and aluminum elements of ion-absorbed-rare-earth ore with a new impurity depressant

Ion-absorbed rare-earth ore is an important mineral resource which is widely extracted by in-situ leaching process. And such process generates a significant amount of impurities such as aluminum and iron ions in leaching solution simultaneously. The surface characteristics and interactions by infrared spectroscopy and X-ray diffraction were studied to optimize the leaching conditions. It is found that the environment-friendly depressant LG-01 can react with the impurity ions through the formation of a new complex on the surface of leaching residues. Thus, it reduces significantly the concentration of impurity ions in leaching solution and improves the leaching rate of rare-earth ore. Moreover, a leaching rate of 95.6% and an impurity removal rate of 92% have been achieved under the optimized conditions.

聚集诱导发光纳米探针在前列腺癌光热诊疗中的应用

背景:基于“分子内运动受限”这一机制构筑的新型聚集诱导发光荧光探针可用于疾病标志物的检测、肿瘤诊断、细菌成像识别等多个方面。目的:构建基于聚集诱导发光的近红外二区纳米探针FA-DSPE-PEG-AIE@NPs,探讨其用于前列腺癌靶向近红外二区荧光成像及光热治疗的潜能。方法:以卵磷脂、聚乙二醇磷脂、叶酸-聚乙二醇磷脂、聚集诱导发光分子2TT-oC26B为原料,采用纳米沉淀法合成叶酸靶向纳米探针FA-DSPE-PEG-AIE@NPs,对其进行基本表征。选取PC3人前列腺癌细胞、人脐静脉内皮细胞为实验对象,检测纳米探针FA-DSPE-PEG-AIE@NPs的细胞毒性与光照毒性;选取PC3人前列腺癌细胞为实验对象,采用流式细胞术和钙黄绿素/碘化丙啶染色法检测该纳米探针的光热治疗效果。选取BALB/C裸鼠腹部皮下注射PC3人前列腺癌细胞建立肿瘤模型,尾静脉注射纳米探针FA-DSPE-PEG-AIE@NPs后立即对小鼠进行近红外二区荧光成像,12 h后激光照射肿瘤5 min,14 d内观察光热治疗效果。结果与结论:①纳米探针FA-DSPE-PEG-AIE@NPs呈球形,平均粒径(171.0±0.3)nm,具有广谱光吸收能力和延伸至近红外二区的尾部发射,在激光辐照下可发出明亮的近红外二区荧光信号;②纳米探针FA-DSPE-PEG-AIE@NPs的细胞毒性低、光毒性高;流式细胞术及钙黄绿素/碘化丙啶染色法显示,纳米探针FA-DSPE-PEG-AIE@NPs对PC3人前列腺癌细胞具有明显的光热杀伤效果;③纳米探针FA-DSPE-PEG-AIE@NPs成功实现了对活体小鼠血管的近红外二区荧光成像,并确认了在肿瘤部位的最大富集时间为12 h,估算后肢腿部及腹部单根血管的血管宽度分别为0.63 mm和0.42 mm,治疗后14 d小鼠肿瘤体积明显减小;④结果表明,纳米探针FA-DSPE-PEG-AIE@NPs能有效实现前列腺癌的近红外二区荧光成像及光热治疗,有望为前列腺癌的早期诊断及联合治疗提供新手段。

Recent developments and applications on high-performance cast magnesium rare-earth alloys

During the past decades,with the increasing demands in lightweight structural materials,Mg alloys with low density and high performance have been extensively investigated and partly applied in some industries.Especially when rare earth(RE)elements are added as major alloying elements to Mg alloys,the alloy strength and creep resistance are greatly improved,which have promoted several series of Mg-RE alloys.This paper reviews the progress and developments of high-performance Mg-RE alloys in recent years with emphasis on cast alloys.The main contents include the alloy design,melt purification,grain refinement,castability,novel liquid casting and semisolid forming approaches,and the industrial applications or trials made of Mg-RE alloys.The review will provide insights for future developments of new alloys,techniques and applications of Mg alloys.

Advance in the chemical synthesis and magnetic properties of nanostructured rare-earth-based permanent magnets

Rare-earth-based permanent magnets are one of the most important magnets in both scientific and industrial fields. With the development of technology, nanostructured rarearth-based permanent magnets with high energy products are highly required. In this article, we will review the progress in chemical synthetic strategies of nanostructured rare-earth-based permanent magnets.

Component Content Soft-sensor Based on Neural Networks in Rare-earth Countercurrent Extraction Process

Throught fusion of the mechanism modeling and the neural networks modeling,a compo- nent content soft-sensor,which is composed of the equilibrium calculation model for multi-component rare earth extraction and the error compensation model of fuzzy system,is proposed to solve the prob- lem that the component content in countercurrent rare-earth extraction process is hardly measured on-line.An industry experiment in the extraction Y process by HAB using this hybrid soft-sensor proves its effectiveness.

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.

Separation and Manipulation of Rare-earth Oxide Particles by Dielectrophoresis

A challenge in chemical engineering is the separation and purification of rare-earth elements and their compounds. We report the design and manufacture of a dielectrophoresis(DEP) microchip of microelectrode arrays. This microchip device is constructed in order to use DEP to capture micro-particles of rare-earth oxides in petro-leum. Dielectrophoretic behavior of micro-particles of rare-earth oxides in oil media is explored. The dielectropho-retic effects of particles under different conditions are investigated. It is showed that the prepared microchip is suit-able for use in the investigation of dielectrophoretic responses of the rare-earth oxides in oil media. The factors such as frequency,particle size and valence of rare-earth metal are discussed. When the frequency is fixed,the transla-tion voltage decreases as particle size increases. Lower frequencies are more effective for manipulation of inorganic particles in oil media. Particles of the same rare-earth oxide with different size,as well as particles of different rare-earth oxides,are captured in different regions of the field by regulating DEP conditions. This may be a new method for separation and purification of particles of different rare-earth oxides,as well as classification of particles with different size.

Unloading behaviors of the rare-earth magnesium alloy ZE10 sheet

Due to their low symmetry in crystal structure,low elastic modulus(~45 GPa)and low yielding stress,magnesium(Mg)alloys exhibit strong inelastic behaviors during unloading.As more and more Mg alloys are developed,their unloading behaviors were less investigated,especially for rare-earth(RE)Mg alloys.In the current work,the unloading behaviors of the RE Mg alloy ZE10 sheet is carefully studied by both mechanical tests and crystal plasticity modeling.In terms of the stress-strain curves,the inelastic strain,the chord modulus,and the active deformation mechanisms,the substantial anisotropy and the loading path dependency of the unloading behaviors of ZE10 sheets are characterized.The inelastic strains are generally larger under compressive Loading-Un Loading(L-UL)than under tensile L-UL,along the transverse direction(TD)than along the rolling direction(RD)under tensile L-UL,and along RD than along TD under compressive L-UL.The basal slip,twinning and de-twinning are found to be responsible for the unloading behaviors of ZE10 sheets.

Structural and mechanical stability of rare-earth diborides

Structural and mechanical properties of several rare-earth diborides were systematically investigated by first principles calculations. Specifically, we studied XB2 , where X=Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Lu in the hexagonal AlB2 , ReB2 , and orthorhombic OsB2 -type structures. The lattice parameters, bulk modulus, bond distances, second order elastic constants, and related polycrystalline elastic moduli （e.g., shear modulus, Young’s modulus, Poisson’s ratio, Debye temperature, sound velocities） were calculated. Our results indicate that these compounds are mechanically stable in the considered structures, and according to ＂Chen’s method＂, the predicted Vickers hardness shows that they are hard materials in AlB2 - and OsB2 -type structures.

Hydrogen production through diesel steam reforming over rare-earth promoted Ni/γ-Al_2O_3 catalysts

Rare-earth （La, Ce, Yb） promoted Ni/γ-Al2O3 catalysts were prepared by impregnation method. Activity and carbon formation resistance of the prepared catalysts were evaluated under various reaction conditions. Catalyst characterizations with TG, TPR and H2 chemisorption were carried out to investigate the promoting mechanism. Experimental results show that rare-earth promoters, especially Yb promoter, obviously improve the activity and carbon formation resistance of Ni/γ-Al2O3 catalyst, and Yb-Ni catalyst shows even higher performance than several commercial catalysts. According to the characterization results, Yb promoter enhances the interaction between the active metal and support, thus increasing the active metal＇s dispersion and improving its performance. Furthermore, the obvious difference in diesel conversion between Yb-Ni catalyst and others was shown in the temperature range of 450-550 °C, which would be the reason for its excellent carbon resistance.

Corrosion rate determination of rare-earth Mg alloys in a Na_(2)SO_(4)solution by electrochemical measurements and inductive coupled plasma-optical emission spectroscopy

The corrosion resistance of three Mg alloys containing rare-earth elements(WE43,EV31 and ZE41)was studied and compared to that of two Mg-Al alloys(AZ31 and AZ91)and of pure Mg(99.95 wt.%).Current-voltage curves and electrochemical impedance measurements were performed with rotating disk electrodes in an aerated 0.1 M Na_(2)SO_(4)solution.For all the alloys,it was confirmed that the intermetallic particles acted as local cathodes and that more protective films were formed on the alloys surface by comparison with the pure Mg.Corrosion rates were determined from inductive coupled plasma-optical emission spectroscopy measurements and from the electrochemical measurements.Higher corrosion rates were observed for the rare-earth Mg alloys compared to the AZ series alloys.These data allowed the corrosion mechanisms to be discussed.

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.