Li(Sc,M)Si_(2)O_(6)∶Cr^(3+)(M=Ga^(3+)/Lu^(3+)/Y^(3+)/Gd^(3+))的近红外发光性能

荧光转换型近红外发光二极管(NIR pc-LED)具有体积小、谱带宽、峰位易调谐等优点,是新一代NIR光源发展的前沿,其关键在于研发可被蓝光有效激发的高效率宽带近红外荧光粉。LiScSi_(2)O_(6)∶Cr^(3+)荧光材料的激发波长为460 nm,发射峰位在845 nm,光谱带宽为156 nm,内量子效率为64.4%。基于该体系,本文通过M离子(M=Ga^(3+),Lu^(3+),Y^(3+),Gd^(3+))取代Sc^(3+)的方式对其性能进行调控。结果表明,引入M离子易生成杂相或发生相变,降低了材料的发光性能。本文从晶体结构出发对其调控过程进行了分析。

{P_(4)Mo_(6)}基多金属氧酸盐构筑的镍配合物作为一种电化学传感器用于检测Cr^(Ⅵ)和Fe^(Ⅲ)离子

以钼酸钠、硫酸镍和3-氨甲基吡啶为原料,通过水热法合成了一个{P_(4)Mo_(6)}基多金属氧酸盐构筑的镍配合物,其化学式为[H_(2)(3-AP)]_(6){Ni[Mo_(6)O_(12)(OH)_(3)(PO_(4))_(2)(HPO_(4))_(2)]_(2)}(化合物1),3-AP为3-氨甲基吡啶.该化合物为三维超分子结构,其由{Ni[P_(4)Mo_(6)^(Ⅴ)O_(31)]_(2)}^(22-)记为{Ni(P_(4)Mo_(6))_(2)}和质子化的3-AP通过氢键相互作用连接而成.研究了该配合物修饰的碳糊电极(1-CPE)对Cr^(Ⅵ)和Fe^(Ⅲ)离子的电化学检测,检出限(LODs)分别为2.3和4.6μmol/L.同时1-CPE在各种金属离子的存在下对Cr^(Ⅵ)和Fe^(Ⅲ)表现出良好的选择性和较强的抗干扰能力.

新型改性煤气化废渣的制备及其吸附含铬废水中Cr^(6+)的研究

为进一步提高煤气化废渣对含铬废水中Cr^(6+)的吸附能力,以某热电厂的煤气化废渣为原料,使用质量分数为16%的硝酸溶液作为主剂,加入增溶剂ZR-1,在超声波辅助条件下对其进行了化学改性,制备出了一种新型改性煤气化废渣MH-GWY,并考察了煤气化废渣改性前后的吸附效果,评价了吸附剂投加量、废水p H值、吸附时间和吸附温度对Cr^(6+)去除率的影响。结果表明:在相同的实验条件下,新型改性煤气化废渣MH-GWY对模拟含铬废水中Cr^(6+)的吸附效果明显优于原煤气化废渣GWY;当废水含Cr^(6+)质量浓度为100 mg/L时,100 m L废水中加入0.3 g吸附剂MH-GWY,控制废水p H值为5,吸附时间为160 min,吸附温度为25℃,Cr^(6+)去除率可以达到96.75%。

改性松果活性炭去除Cr^(6+)的研究

为了提高水中Cr^(6+)的去除效率,以松果粉末(PC)为原料,利用H_(3)PO_(4)改性法制备了低成本高比表面的改性松果活性炭(PCAC)。采用扫描电子显微镜、X射线衍射仪、傅里叶红外光谱仪和全自动比表面积分析仪对PCAC表面理化性质变化进行表征。通过静态吸附实验探究其对Cr^(6+)的吸附性能,测定了溶液初始pH、PCAC投加量和吸附时间对Cr^(6+)吸附性能的影响。根据吸附动力学和吸附等温线,探讨了PCAC对Cr^(6+)的吸附机理。结果表明:经H_(3)PO_(4)改性制备的PCAC比表面积和孔隙体积分别为1669.2m^(2)/g和0.851cm^(3)/g,高于未改性的PC;对于100mg/L Cr^(6+)模拟废水,最佳吸附条件:pH=2、PCAC投加量0.5g、吸附时间3h,此时PCAC对Cr^(6+)的去除率最大且为99.97%;吸附动力学数据拟合分析,拟二级动力学模型较好地描述了PCAC对Cr^(6+)吸附行为;Langmuir等温线模型拟合效果最好,吸附过程为单分子层吸附,且最大吸附容量为34.43616mg/g。

Photocatalytic Reduction of Cr^Ⅵ by Natural Sphalerite Suspensions under Visible Light Irradiation

The photocatalytic reductive capability of a natural semiconducting mineral, sphalerite has been studied for the first time. The sphalerite from the Huangshaping deposit of Hunan Province performed great photoreductive capability that 91.95% of the Cr^6＋ was reduced under 9 h visible light irradiation, higher than the 70.58% under 9.5 h UV light irradiation. The highly reductive ability results from its super negative potential of electrons in the conduction band. Furthermore, Fe substitution for Zn introduces donor states, and the oxidation process of Fe^2＋ to Fe^3＋ makes it an effective hole-scavenger. Cd and Cu substitute for Zn also reduce the bandgap and help broaden the absorbing edge towards the visible light. These substituting metal ions in natural sphalerite make it a hyper-active photocatalyst and very attractive for solar energy utilization.

Regio-and Stereo-selective Reductions of Steroidal 4-en-3,6-dione

The different regioselective and stereoselective products were obtained by the reduction of stigmast-4,22-dien-3,6-dione with NaBH_4-CH_3OH when different kinds of metal ions was added to the reaction.

Influence of Coal Fly Ash Particle Size on Structure and Adsorption Properties of Forming Adsorbents for Cr^6＋

Forming adsorbents FFA-R,FFA-A and FFA-B were prepared from different particle size coal fly ashes FA-R,FA-A and FA-B,their average particle sizes（d_（50）） were 15.75,3.61 and 1.73 μm respectively.The structure and adsorption properties for Cr^（6＋） of forming adsorbents from aqueous solution were studied.The results show that forming adsorbent prepared from the coal fly ash with smaller particle size exhibits higher specific surface area,higher pore volume and better adsorption properties for Cr^（6＋）.The adsorption kinetics of Cr^（6＋） on FFA-R,FFA-A and FFA-B fitts the second order kinetic model and the second adsorption rate constants are 7.523,3.197 and 2.187 mg·g^（-1）·min^（-1/2）,respectively.The adsorption of Cr^（6＋） on FFA-R,FFA-A and FFA-B can be described in terms of Langmuir isotherms better,and the adsorption processes are spontaneous and exothermic.

玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)的吸附性能研究

用玉米芯和枯草芽孢杆菌两种材料,制备了一种微生物吸附剂。以废水中Cr^(6+)的吸附率为指标,探究了在不同温度、时间、投加量和pH的条件下,玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)的吸附产生的影响。通过响应面法确定了玉米芯粉固定枯草芽孢杆菌对废水中Cr^(6+)吸附的最佳条件。实验结果表明:玉米芯粉固定枯草芽孢杆菌在温度35℃、pH=4.7、振荡时间63 min时,对废水中Cr^(6+)的吸附效果更好,其去除率达到89.64%。

纳米碳管复合及聚苯胺包覆Sb_(2)MoO_(6)复合材料的制备及储锂性能研究

以三氟化锑和钼酸铵为锑源和钼源,采用水热法制备出锑钼锑(Sb_(2)MoO_(6))和Sb_(2)MoO_(6)/纳米碳管(CNTs)复合物,利用苯胺聚合在Sb_(2)MoO_(6)和Sb_(2)MoO_(6)/CNTs上继续包覆聚苯胺(PANI)得到Sb_(2)MoO_(6)@PANI (Sb_(2)MoO_(6)/CNT)@PANI。采用XRD、SEM、EDX等手段对样品结构和形貌进行表征,结果发现制备的Sb_(2)MoO_(6)为不均匀的长为10μm的棒状形貌,而CNTs复合后的Sb_(2)MoO_(6)形貌变成厚约为100 nm的片状。作为锂离子电池负极材料,对所有合成的样品进行电化学性能测试,探讨CNTs复合和聚苯胺(PANI)包覆对Sb_(2)MoO_(6)样品的电化学性能的影响。结果表明:Sb_(2)MoO_(6)@PANI、Sb_(2)MoO_(6)/CNTs、(Sb_(2)MoO_(6)/CNTs)@PANI样品的电化学性能均优于Sb_(2)MoO_(6),其中(Sb_(2)MoO_(6)/CNT)@PANI具有最佳的电化学性能。(Sb_(2)MoO_(6)/CNT)@PANI在电压范围为0.01~3 V、电流密度为100 mA·g^(-1)条件下,循环100圈后,放电比容量为650 mAh·g^(-1)。CNTs复合和PANI包覆后的Sb_(2)MoO_(6),颗粒粒径大大降低,还增加了钼酸锑的导电性(阻抗161Ω),在电化学循环过程中有效延缓了Sb_(2)MoO_(6)材料的体积崩塌。

Cs_(2)NaGdCl_(6)∶Sb^(3+)荧光粉制备及发光性能

无铅双钙钛矿材料具有高效、稳定的自陷激子发射,在下一代固态照明中显示出巨大的潜力。本文采用微波固相法制备出系列新型的Cs_(2)NaGdCl_(6)∶Sb^(3+)蓝色荧光粉。通过X射线衍射仪、扫描电子显微镜和荧光光谱仪对所制备样品的结晶性、微观形貌和发光性能进行了表征和分析。结果表明,所制备的双钙钛矿型Cs_(2)NaGdCl_(6)∶Sb^(3+)样品属于立方晶系,空间群Fm3m,大小为10μm的不规则颗粒。在336 nm激发光下,荧光粉在460 nm处发射出极强的蓝光,且不同Sb^(3+)离子掺杂浓度的样品色坐标均在蓝光区域。当Sb^(3+)离子掺杂浓度超过0.015时,发生浓度猝灭,归因于电偶极⁃电偶极相互作用。此外,Cs2NaGd0.985Cl6∶0.015Sb^(3+)样品具有较佳的热稳定性,当温度升高至423 K时,发光积分强度仍为323 K时的72.6%。基于上述研究结果,Sb^(3+)离子激活Cs_(2)NaGdCl_(6)蓝色荧光粉在发光二极管领域具有潜在的应用价值。

Evaluation of sex specificity on oxidative stress induced in lungs of mice irradiated by ^(12)C^(6+) ions

The aim of this work is to identify if there is sex specificity on 12C6+ ion-induced oxidative damage in mouse lung at different time points. Kun-Ming mice were divided into two groups, each composed of six males and six females: control group and irradiation group with a single acute dose of 4 Gy. Animals were sacrificed at 2, 4 and 12 h respectively, there lungs were removed immediately, and the oxidative stress-related biomarkers were measured by Diagnostic Reagent Kits. The results showed that the relative activities of superoxide dismutase (4 h), catalase (2 h) and Se-dependent glutathione peroxidase (12 h) have significant changes (P<0.05) between male groups and female groups, suggesting that the lungs of male mice are more sensitive to counteracting the oxidative challenge. Moreover, higher levels of malondiadehyde and lower contents of glutathione were also found in males, indicating that oxidative stress induced by 12C6+ ion is pronounced in the lungs of males. We thought that these sex-responded differences may be attributed to the influence of sex hormones.

Multi-Electron Processes in 4.15-11.08 keV/u^13C^6＋ on Argon Collisions

The relative partial cross sections for ^13C^6＋ -Ar collisions at 4.15-11.08 ke V/u incident energy are measured. The cross-section ratios σ^2E/σ^SC, σ^3E/σ^SC, σ^4E/σ^SC and σ^SE/σ^SC are approximately the constants of 0.514-0.05, 0.204-0.03, 0.064-0.03 and 0.024-0.01 in this region. The significance of the multi-electron process in highly charged ions （HCIs） with argon collisions is demonstrated （σ^ME/σ^SC as high as 0.794-0.06）. In multi-electron processes, it is shown that transfer ionization is dominant while pure electron capture is weak and negligible. For all reaction channels, the cross-sections are independent of the incident energy in the present energy region, which is in agreement with the static characteristic of classic models, i.e. the molecular Coulomb over-the-barrier model （MCBM）, the extended classical over-the-barrier model （ECBM） and the semiempirical scaling laws （SL）. The result is compared with these classical models and with our previous work of ^13C^6＋ -Ne collisions [Chin. Phys. Lett. 23 （2006） 95].

(BiBr_(6))^(3-)作为抗衡离子的稀土18-冠-6配合物的合成与晶体结构

将Ln_(2)O_(3),BiBr_(3)和18-冠-6在氢溴酸(HBr)条件下混合反应,得到2个新型配合物[Ln(18-冠-6)(H_(2)O)_(4)](BiBr_(6))·3.5H_(2)O[Ln=Nd(1)和La(2)].单晶结构分析表明,化合物1和2是异质同构体,均结晶于单斜晶系C 2/c空间群.以化合物1为例,其晶胞参数a=23.691(2),b=13.7758(11),c=20.2969(18),α=γ=90°,β=108.063(5)°.化合物1中的一个Nd^(3+)离子被冠醚的6个氧原子螯合,并与冠醚环上下的两对配位水分子进一步配位,形成单核[Nd(18-冠-6)(H_(2)O)_(4)]^(3+)离子,该阳离子与抗衡阴离子(BiBr_(6))^(3-)形成的离子对,分别从两个不同的维度以“之”字形交替堆叠形成三维结构,晶格水分子填充在空隙空间中.

金属-有机骨架离子凝胶膜的制备及其在C_(3)H_(6)/C_(3)H_(8)分离中的应用

通过调节反应时间合成出3种不同颗粒大小金属-有机骨架(ZIF-8),并将其与离子液体1-丙基-3-甲基咪唑双三氟甲磺酰亚胺盐(PmimTf_(2)N)和聚醚共聚酰胺(Pebax 1657)混合制得ZIF-8/IL/Pebax离子凝胶膜,用于对丙烯/丙烷混气体系的分离.通过ZIF-8颗粒与离子液体在Pebax膜中的协同作用,实现了金属-有机骨架(MOF)填料在聚合物基质中高达70%的质量掺杂量,C_(3)H_(6)/C_(3)H_(8)体系的气体分离性能也得到明显提升.研究表明,ZIF-8/IL/Pebax离子凝胶膜相比于Pebax纯膜,C_(3)H_(6)渗透通量提高了385%,达到了227.1 Barrer;同时,C_(3)H_(6)/C_(3)H_(8)的选择性也从3.04提高到了25.11.此外,在不同温度和压力条件下(10~40℃,0.15~0.3 MPa),ZIF-8/IL/Pebax离子凝胶膜均表现出优异的气体分离性能,并表现出了良好的应用前景.

CdI₂Extraction with 18-Crown-6 Ether into Various Diluents: Classification of Extracted Cd(II) Complex Ions Based on the HSAB Principle

CdI2 in water was extracted with 18-crown-6 ether (L) into 10 diluents at 298 K. The following equilibrium constants were determined or evaluated: some extraction constants (Kex/mol-3·dm9 & Kex,ip/mol-2·dm6 for CdLI2, Kex±/mol-2·dm6 for CdLI+ with I-, & Kex2±/mol-1·dm3 for CdL2+ with 2I-), conditional distribution constants (KD,I for I-, KD,CdLI for CdLI+, & KD,CdL for CdL2+) between the two phases, and an ion-pair formation constant (K1,org/mol-1·dm3) for CdLI+ and that (K2,org/mol-1·dm3) for CdLI2 in the organic (org) phases. Using the K1,org and K2,org values, acidities of the complex ions, CdL2+ and CdLA+ (A- = I-, Br-, & Cl-), in the 11 diluents were classified by applying the HSAB rule. Especially, the CdLA+ ions were classified as the soft acids in 9 diluents. Also, molar volumes (Vj/cm3·mol-1) of j = CdLI2 and CdL2+ were determined with the regular-solution-theory plot of logKex,ip vs. logKD,L and its pseudo-plot of logKD,CdL, respectively. Here, KD,L denotes the distribution constant of L between the two phases. So, sizes among CdLA2 and CdL2+ were compared by using the Vj values. Additionally, some distribution equilibrium potentials (dep/V) between the water and org bulk phases were topically calculated from an equation of KD,I with KSD,I, where the symbol KSD,I shows a standard distribution constant of I- at dep = 0 V for a given diluent.

Cr^(6+)、Cr^(3+)胁迫对黑藻生理生化影响的比较研究

以沉水植物黑藻 (Hydrillaverticillata(L .f.)Royle)为实验材料 ,通过模拟水体Cr6+ 、Cr3 + 污染环境 ,比较研究了两种价态铬对黑藻叶的毒害影响。结果表明 :随着Cr6+ 、Cr3 + 浓度的加大 ,超氧阴离子 (O 2)产生速率、丙二醛 (MDA)、可溶性蛋白含量皆呈先升后降趋势。Cr6+ 、Cr3 + 浓度过高时 ,三种抗氧化酶 (SOD、POD、CAT)活性比例失衡 ,且Cr6+ 处理组的O 2 产生速率、MDA含量高于Cr3 + 处理组 ,叶绿素、可溶性蛋白含量、叶绿素a/b值低于Cr3 + 处理组 ,显示出Cr6+ 的毒性远大于Cr3 + 。

化妆品及保健品中Cr^(3+)和Cr^(6+)的柱后衍生-离子色谱法测定

建立了化妆品和保健品中Cr3+、Cr6+的柱后衍生-离子色谱检测法。样品中的铬经柱前络合为2,6-嘧啶二羧酸铬,柱后衍生为1,5二苯碳酰二肼铬,于520 nm波长检测。优化了衍生反应条件,提高了检测灵敏度,Cr3+和Cr6+方法检出限(LODs,3σ)分别为0.12、0.011 mg/kg。样品加标回收率为89%~108%,重复性好。共存离子Fe2+、Fe3+、Pb2+、Cu2+、Al3+、Zn2+、Hg2+等,以及常见有机物均不干扰测定。

Cr^(3+)和Cr^(6+)胁迫对茶树生理生化特性的影响

通过水培试验,研究比较了不同浓度(10～60mg/L)的Cr3+、Cr6+胁迫对茶树叶片一些生理生化指标的影响。结果表明:随Cr3+、Cr6+胁迫浓度的增加,茶树受害程度加深,中毒症状明显;叶绿素含量以及叶绿素a/b比值极显著降低,并对净光合速率、胞间CO2浓度、蒸腾速率及气孔导度产生显著负面影响。Cr3+胁迫下,SOD、POD、CAT活性随Cr3+浓度增加呈先升高后降低趋势;而Cr6+胁迫下,SOD、POD活性也出现先升后降趋势,但CAT活性则持续下降。丙二醛含量、细胞膜透性和脯氨酸含量也随Cr3+、Cr6+浓度增加显著增加,表明Cr3+、Cr6+胁迫对茶树细胞质膜系统及主要细胞器的结构与功能都具有较强的破坏作用,Cr6+的毒害作用强于Cr3+。

地衣芽孢杆菌(Bacillus licheniformis)对Cr^(6+)的吸附动力学研究

从污染土壤中分离出地衣芽孢杆菌(Bacilluslicheniformis),利用其死菌体对Cr6+溶液进行吸附动力学研究.在Ci=300mg/L、pH=2.5和θ=50℃条件下,吸附120min获得最大吸附量60.5mg/g.应用Langmuir和Freundlich吸附等温线研究,结果表明,Langmuir吸附等温线更为适合.动力学研究显示,地衣芽孢杆菌对Cr6+的吸附动力学可以用拟二级速度方程进行描叙.

钙矾石对Cr^(6+)和Cu^(2+)的固化及稳定性

通过溶液法人工合成钙矾石,分析比较了水化形成过程中钙矾石对Cr6+和Cu2+固化机制及其稳定性。结果表明,Cr6+和Cu2+均可对钙矾石晶格结构产生一定影响,但两者在钙矾石中固化机制并不完全相同。Cr6+挤入钙矾石晶格层间结构,改变了分子对称性,对钙矾石晶体结构有较大影响;而Cu2+对钙矾石晶体结影响较小。在水化液相中重金属离子含量较低时,钙矾石对Cu2+、Cr6+俘获能力较高,且少量Cu2+对钙矾石晶体生长发育促进作用;而重金属离子含量较高时,钙矾石对Cr6+俘获能力明显下降,但对Cu2+的固化能力仍较高。钙矾石对Cu2+固化受环境条件影响较小,同时少量Cu2+在一定程度上有利于稳定碳化条件下钙矾石晶形结构;而钙矾石对Cr6+的固化受外界环境因素影响较大,且碳化、冻融、氯盐侵蚀多因素复合对其固化稳定性有极大影响。