(Cκ-K)性质的对偶性质

引入了Banach空间的(Sk-K)性质,以局部自反原理为工具证明了(CkK)性质与(Sk-K)性质的对偶关系,并讨论了(Sk-K)性质与LNUS空间和L-kS(wL-kS,CL-kS,wCL-kS)空间的关系,得到如下结果:X是L-kS(wL-kS,CL-kS,wCL-kS)空间分别等价于(Sk-I)((Sk-I'),(Sk-Ⅱ),(Sk-Ⅲ))性质.     

偏振X射线荧光分析尾矿薄层样品的散射校正方法研究

了解尾矿浆中的重金属元素含量能为矿物浮选提供决策依据,不仅可以提高矿物的利用率,还可减少环境污染。X射线荧光光谱法是一种常用的重金属元素分析技术,对于地质类样品的分析,康普顿散射内标法是一种常用的定量方法。但对于薄层沉积样品,其康普顿散射峰强度会受到支撑滤膜的散射影响。由于样品紧密附着在支撑滤膜上,难以直接获得来自样品本身的康普顿散射强度,不利于直接应用康普顿散射峰强度进行定量分析。以尾矿薄层样品为分析对象,研究了不同聚丙烯滤膜厚度对康普顿散射峰强度的影响,并对薄层样品的康普顿散射强度进行了校正。实验结果表明,在0.34～3.06 mm厚度范围内,康普顿散射峰强度随聚丙烯滤膜厚度的增加线性增加,通过建立探测器获得的总康普顿散射强度与滤膜厚度的线性关系,计算出样品的净康普顿散射峰强度。为验证该修正方法的可靠性,利用蒙特卡洛方法模拟研究了无滤膜的尾矿样品和带有不同厚度滤膜的尾矿样品,结果显示经滤膜厚度影响修正后的净康普顿散射峰强度与无滤膜样品康普顿散射峰强度基本一致,相对偏差为0.41%。同时通过实验和模拟计算了0.34 mm厚聚丙烯滤膜时修正后的净康普顿散射峰强度占总康普顿散射峰的比例,分别为91.31%和89.91%,二者基本一致。最后,利用了上述基于滤膜厚度康普顿散射影响的校正方法,建立了基于康普顿散射内标法的定量校准曲线,对两种尾矿浆中的Cu,Zn和Pb元素的定量分析结果显示,未经滤膜厚度修正的康普顿内标校正相比校正前,部分元素定量结果与ICP-OES结果相比,其相对偏差反而增加3.18%～9.00%。而经滤膜厚度修正的康普顿内标方法的定量结果与ICP-OES结果的相对误差在1.14%～11.15%之间,相比于校正之前,相对偏差减少了0.30%～8.97%。     

Recent Advances of Pure Organic Room Temperature Phosphorescence Materials for Bioimaging Applications

Bioimaging,as a powerful and helpful tool,which allows people to investigate deeply within living organisms,has contributed a lot for both clinical theranostics and scientific research.Pure organic room temperature phosphorescence(RTP)materials with the unique features of ultralong luminescence lifetime and large Stokes shift,can efficiently avoid biological autofluorescence and scattered light through a time-resolved imaging modality,and thus are attracting increasing attention.This review classifies pure organic RTP materials into three categories,including small molecule RTP materials,polymer RTP materials and supramolecular RTP materials,and summarizes the recent advances of pure organic RTP materials for bioimaging applications.     

基于1,4-双(咪唑-1-基)苯的Mn(Ⅱ)/Co(Ⅱ)配位聚合物的合成、晶体结构及性质

在溶剂热条件下,合成了3个新的配位聚合物{[Mn₃（oba）₃（bib）（DMF）（H₂O）]·DMF}_n（1）、[Co（Hoba）₂（bib）]_n（2）和{[Co（aip）（bib）]·DMF}_n（3）（bib=1,4-双（咪唑-1-基）苯,H₂oba=4,4''-二苯醚二甲酸,H₂aip=5-氨基间苯二甲酸,DMF=N,N-二甲基甲酰胺）,分别用元素分析、红外光谱、紫外可见光谱、热重分析、X射线单晶衍射、粉末X射线衍射对其进行了表征。结构分析表明：配合物1呈现三维网络结构,拓扑符号为{3¹⁸;4³⁷;5²⁴;6¹²}{3⁹;4¹²;5²;6³;7²}{3⁹;4¹²;5³;6⁴};配合物2的一维链通过O—H…O氢键连结成三维超分子,拓扑结构为{10}{8;10⁴;14}{8³}₂;配合物3的二维层状结构通过N—H…O氢键连成三维超分子,拓扑结构为{3³;4¹⁰;5;6}。配合物1能快速从染料混合物中选择性吸附刚果红。配合物2和3分子内Co（Ⅱ）离子之间存在弱的反铁磁相互作用。     

Rapid detection of pathogenic bacteria based on a universal dual-recognition FRET sensing system constructed with aptamer-quantum dots and lectin-gold nanoparticles

The threat to public health from bacterial infections has led to an urgent need to develop simpler, faster and more reliable bacterial detection methods. In this work, we developed a universal dual-recognition based sandwich fluorescence resonance energy transfer (FRET) sensor by using specific aptamer-modified quantum dots (Aptamer-QDs) as energy donor and lectin concanavalin A (Con A) modified gold nanoparticles (Con A-AuNPs) as energy acceptor to achieve rapid and sensitive detection of Escherichia coli (E. coli) within 0.5 h. In the presence of the target E. coli, the energy donor of Aptamer-QDs and acceptor of Con A-AuNPs were close to each other, causing changes of FRET signals. Based on the constructed FRET sensor, a linear detection range of from 10² cfu/mL to 2 × 10⁸ cfu/mL with the detection limit of 45 cfu/mL for E. coli was achieved. Furthermore, the FRET sensor was applied to detect E. coli in the milk and orange juice with the detection limit of 300 cfu/mL and 200 cfu/mL, respectively and recovery rate from 83.1% to 112.5%. The strategy holds great promise in pathogenic bacteria detection due to its rapid and sensitivity.     

Organic salt-derived phosphorus-doped mesoporous carbon for high performance supercapacitors

Phosphorus-doped mesoporous carbons (PMCs) were prepared using a self-doping and self-templating approach via direct pyrolysis of sodium phytate (C₆H₁₇NaO₂₄P₆). The one-pot method allows simultaneous carbonization and P doping, eliminating the need for pre-synthesis or post-activation treatment. The C₆H₁₇NaO₂₄P₆ is the source of both carbon and phosphorus, and the nano-Na₄P₂O₇ particles produced during pyrolysis act as hard templates for the honeycomb mesoporous structure with high specific surface area (884–827 m²/g), large mesopore volume ratio (67%–75%) and rich phosphorus content (0.53–2.34 at%). As electrodes of supercapacitors in 6 mol/L KOH, the PMCs showed outstanding performance with a high capacitance of 202 F/g and excellent rate performance of 148 F/g at 30 A/g. In addition, the PMCs-based symmetrical supercapacitors can operate in an expanded working voltage of 0–1.6 V in 3 mol/L H₂SO₄ aqueous electrolytes with high-density energy of 11.8 Wh/kg.     

Corrosion and electrochemical behavior of water glass coatings embedded with graphite/titanium oxide on 2A12 aluminum alloy

Journal of Solid State Electrochemistry - Graphite/titanium oxide composite anti-corrosion coatings with five proportions of graphite were applied on the surface of aluminum alloy. The surface...     

Representation of a Class of Linear Operators with Coupled Domain in a Product Space and Its Applications

Acta Mathematica Sinica, English Series - This paper is concerned with the representation problem of a coupled operator in a product space. A necessary and sufficient condition is given for a class...     

Synthesis, thermionic emission and magnetic properties of (NdxGd1-x)B6

Polycrystalline rare-earth hexaborides(NdxGd1-x)B6(x = 0,0.2,0.6,0.8,1) were prepared by the reactive spark plasma sintering(SPS) method using mixed powder of GdH2,NdH2 and B.The effects of Nd doping on the crystal structure,the grain orientation,the thermionic emission and the magnetic properties of the hexaboride were investigated by X-ray diffraction,electron backscattered diffraction and magnetic measurements.It is found that all the samples sintered by the SPS method exhibit high densities(> 95%) and high values of Vickers hardness(2319 kg/mm2).The values are much higher than those obtained in the traditional method.With the increase of Nd content,the thermionic emission current density increases from 11 to 16.30 A/cm2 and the magnetic phase transition temperature increases from 5.85 to 7.95 K.Thus,the SPS technique is a suitable method to synthesize the dense rare-earth hexaborides with excellent properties.