云南红宝石暗色条带改善研究

热处理可以有效地消除云南红宝石中的暗色条带,降低杂色影响,红宝石的红色调明显得以改善。通过能散X射线荧光测得,从红宝石内部析出的元素主要为Fe。吸收光谱测试结果显示,热处理后红宝石的吸收峰强度增强并发生蓝移现象,红色调加强,饱和度提高。     

桂林水热法合成红、蓝宝石的宝石学研究

桂林水热法合成红宝石带有橙色色调,具有与天然红宝石及橙红色蓝宝石没的吸收光谱,由Cr^ ,Mn^3 ,Ni^3 等过渡离子致色,浅黄色合成蓝宝石由Ni^3 致色,与天然黄蓝宝石的吸收光谱特征不同,最具普遍意义的鉴定特征是种晶片残余,呈面现状分布的法埃状包裹体以及缺少明星的生长纹理的和含水的红外吸收光谱。     

扩散处理合成蓝宝石的特征及其扩散机制

以焰熔法合成无色蓝宝石为基体、采用Fe和Ti化合物为渗色剂、在超高温条件下进行扩散处理的合成蓝宝石近期出现在国内外珠宝市场上。采用EPMA,FTIR,UV-VIS等分析测试方法,对扩散处理合成蓝宝石的宝石学特征及其扩散机制进行了测试与研究。结果表明,扩散处理合成蓝宝石渗层的主要化学成分w(FeOT)为1.69%~1.02%,w(TiO2)为0.57%~0.39%,其横断面上FeOT和TiO2化学配比极不均匀,化学成分自外向内呈现较明显的分带现象;Fe2 /Ti4 荷移是导致扩散处理合成蓝宝石中VIS吸收光谱b带(573~578 nm)形成并呈色的主要原因,当w(FeOT)∶w(TiO2)≤3∶1时,有利于维持渗层中Fe2 /Ti4 荷移的基本配比关系,从而形成蓝色渗层;扩散处理合成蓝宝石的红外吸收光谱中,一组由v(OH)伸缩振动致红外吸收弱谱带分别出现在3 371,3 309,3 231 cm-1处,并伴有v(NH)伸缩振动致3 186 cm-1红外吸收弱谱带;此外,扩散处理合成蓝宝石的刻面上残留不规则的网状淬火裂纹及热蚀凹坑,内部存在气泡或气泡群,在SW下发出强度不等且不均匀的蓝白色荧光。研究认为,扩散处理合成蓝宝石中Fe2 和Ti4 离子的微观扩散迁移作用受控于表层空位迁移能、空位扩散系数及空位浓度梯度。     

桂林水热法合成红宝石的宝石学特征及呈色

采用传统的宝石学研究方法，并配合IR，UV－VI和EPMA测试分析方法，对新近生长的桂林水热法合成红宝石的宝石学特征及呈色进行了初步研究，结果表明，该类合成红宝石中普遍存在Al-OH伸缩振动致弱谱带（3307，3231，3013cm^-1)和KHCO3中O－H伸缩振动致弱谱带（2365，2348cm^-1），它们是鉴别类合成红宝石的重要依据。     

百里酚蓝荷移分光光度法测定药片中琥乙红霉素含量

利用琥乙红霉素与百里酚蓝在乙醇介质中发生荷移反应,建立了荷移分光光度法测定药片中琥乙红霉素的含量的方法.结果表明,荷移反应生成1:1型配合物,最大吸收波长为440 nm,表观摩尔吸光系数为6.6×103 L·mol-1·cm-1,琥乙红霉素测定线性范围为1.724～146.600 ms/L.     

未经热处理及热处理的缅甸红宝石的特征对比

从泰国一宝石处理商处获得一批未经热处理和热处理的缅甸红宝石,对其基本宝石学特征、化学成分、红外光谱及紫外-可见吸收光谱进行测试分析,以期获得经热处理后的红宝石的特征,并与未经热处理的缅甸红宝石相区别。测试结果表明:热处理红宝石内有大量的次生熔体包裹体,而未经热处理红宝石内仅观察到矿物晶体包裹体以及流体包裹体;在化学成分上,热处理红宝石中的Ti元素平均含量较高,Fe元素平均含量较低,相比于未经热处理红宝石分别高了约1 000×10~(-6)以及低了约100×10~(-6);未经热处理红宝石可检测到硬水铝石的吸收峰以及结构水和游离水的吸收峰,而热处理红宝石由于受高温的破坏,均检测不到这些特征吸收峰;热处理红宝石位于694 nm附近的荧光峰整体上比未经热处理红宝石更强且尖锐。     

天然与合成紫晶的3 543 cm-1红外吸收谱带及其鉴定价值

重点对3 800～3 000 cm-1范围的红外吸收光谱在鉴别天然与合成紫晶中的适用性和局限性进行了研究.3 680, 3 664, 3 630 cm-1处吸收带的存在可以确认紫晶为人工合成的, 但仅指那些在近中性NH4F溶液中合成的紫晶.相反, 商业上大量的合成紫晶是在碱性K2CO3溶液中合成的, 这些紫晶的红外吸收光谱并无明显的鉴定特征.前人的研究发现了在近3 595, 3 543 cm-1处吸收带的潜在鉴定价值.3 595 cm-1吸收带在合成紫晶的红外吸收光谱中并未出现, 在一些天然紫晶中也常常缺失.3 543 cm-1吸收带出现在绝大多数碱性溶液中合成紫晶的红外吸收光谱中, 但有时也在天然紫晶中出现.因此, 它只是鉴别合成紫晶的临时性证据.3 543 cm-1吸收带在有些类型的合成紫晶中缺失.要准确地鉴定天然与合成紫晶一定要根据其红外光谱、内部生长结构(包括双晶)和包裹体特征综合判断.     

蒙素红宝石

自1992年以来,曼谷市场上出现了大量缅甸蒙素产出的红宝石。蒙素红宝石产于大理岩中,具双锥至桶状晶形,核部呈暗紫色至近黑色,边部呈红色。经热处理,能去除蓝色调,核部变成深红色。这种红宝石生长条件不断变化,生长周期复杂。核部和边部的颜色分布与晶体生长过程中铬和/或钛的含量不同有关。本文就蒙素红宝石在宝石学、显微镜下,化学和光谱方面的特征,提出与合成红宝石及其它产地红宝石的区别,同时也提到因人工裂隙充填而引起的一些问题。     

助熔剂生长法合成尖晶石及其宝石学特征

助熔剂生长法合成尖晶石及其宝石学特征王德荫尖晶石、尤其是红尖晶石是最美丽的宝石材料之一，自古以来即以其色彩鲜艳、光泽耀眼而深受人们喜爱。在镶嵌首饰中红尖晶石常被作为红宝石的代用品，而蓝尖晶石则常代替海蓝宝石与蓝宝石等。近年来市场上又出现了大量合成尖晶...     

鲣鱼4℃贮藏期间色素物质及脂质氧化的变化

分析了4℃贮藏期间鲣鱼普通肉和暗色肉色素物质及脂质的氧化情况。试验结果表明:暗色肉的总色素物质、血红素铁、高铁肌红蛋白含量(metMb%)以及红度值明显高于普通肉,暗色肉的氧化程度也明显高于普通肉。两种肌肉的总色素含量在第2天达到最大值,分别为968.6,121.6 mg/(kg肉)。metMb%主要呈上升趋势,暗色肉在第12~15天metMb%明显下降(P0.05)。两种肌肉肌红蛋白粗提液在波长350~750 nm范围的扫描结果表明:在波长410 nm处发生蓝移现象,氧合肌红蛋白特征吸收峰(536 nm和575 nm波长处)逐渐消失,高铁肌红蛋白特征吸收峰(500 nm和630 nm波长处)逐渐出现。暗色肉和普通肉的PV值逐渐增加,分别在第12天和第9天达到最大值,为368、185.8μmol过氧化氢异丙苯/(kg肉),随后呈下降趋势;两种肌肉的硫代巴比妥酸反应产物值逐渐增加,后期增加量较为显著。     

缅甸、越南红宝石的热处理研究

对缅甸、越南带有蓝紫色调的天然红宝石样品进行了热处理改善工艺研究,采用激光诱导离解光谱仪（LIBS）和X射线荧光能谱仪（EDXRF）对样品进行定性和定量测试,结果显示,样品中含有Al、Fe、Cr、Ca、Mg、Ti、Si等元素,且随着红宝石紫色调的加深,Fe的质量分数增加。热处理实验中对加热温度、加热时间及速率、添加剂等适当调控,从而得出最佳实验方案;利用USB 4000对处理前、后的样品进行测试分析,结果显示在温度为1 580℃,氧化氛围,添加剂为硼酸钠和三氧化二铝的条件下的热处理工艺,能够很好地改变微量元素Fe,Ti的存在状态,减少由其产生的紫色调、蓝紫色调,使红色纯正。由于样品裂隙发育,即使有助熔剂充填,也并不能很好的改善其透明度,只是在裂隙中残留下白色物质。     

Novel catalytic activity of nitrile hydratase from Rhodococcus sp. N771

Nitrile hydratase (NHase) from Rhodococcus sp. N771 is a non-heme iron enzyme catalyzing the hydration of various nitriles to the corresponding amides. We report a novel catalytic activity of NHase. When NHase was incubated with an large excess of commercially available isovaleronitrile, the charge transfer band from the sulfur ligand to the Fe atom shifted from 710 nm to 820 nm, but recovered within 4 min. Similar UV-Vis absorption changes were observed after the addition of isobutylisonitrile (iBuNC), a major impurity in commercially available isovaleronitrile, suggesting that NHase catalyzes the conversion of iBuNC to other compounds. The reaction product was identified as isobutylamine (iBuNH(2)) by liquid chromatography tandem mass spectrometry. NHase also converts t-butylisonitrile and 1,1,3,3,-tetramethylbutylisonitrile to the corresponding amines. Kinetic analysis of the conversion of iBuNC to iBuNH(2) showed a K(m) value comparable to that for nitriles, while the V(max) value was more than 10(5) times smaller than that for methacrylonitrile. This is the first report suggesting that NHase is a bifunctional enzyme catalyzing a reaction other than the hydration of nitriles.     

Zultanite(变色水铝石)的宝石学及谱学特征

Zultanite(变色水铝石)是仅产自土耳其的奇异变色宝石。采用常规宝石学测试方法、傅里叶变换红外光谱仪、激光拉曼光谱仪、紫外-可见分光光度计和激光剥蚀电感耦合等离子体质谱仪等测试仪器分析变色水铝石的宝石学特征及谱学特征,并对其变色机理进行了探究。结果表明,变色水铝石样品的红外光谱主要由—OH和—OD的振动引起,其拉曼光谱主要由—OH和Al—O键的振动引起;变色水铝石样品的主要杂质元素有Fe、Si、Ti,还含微量的Ga、Cr元素;样品的紫外-可见光谱中Fe~(3+)的d—d电子跃迁与Fe~(3+)—Fe~(3+)离子对的跃迁共同作用引起371、385、397、448nm处的强吸收。Fe~(2+)—Ti ~(4+)的电荷转移与微量Cr~(3+)引起575nm左右的宽缓吸收。由此推断,变色水铝石的变色效应主要由Fe、Ti元素的综合作用导致,Cr元素影响微弱。     

巧克力珍珠的呈色与成因属性

采用LA-ICP-MS、拉曼光谱仪、微型光纤光谱仪等分析测试仪器,对近期市场上出现的巧克力珍珠样品的化学成分、拉曼光谱、反射光谱、表面微观特征及其成因属性进行了初步研究。分析与测试结果表明,多数巧克力珍珠样品内发育有简单且着色外浅(棕黄色、棕红色)内深(灰黑色)的同心色带结构,深浅不一的棕红色色斑和灰白色色斑沿珍珠层表面相间无序分布;经低温加热漂白处理后,巧克力珍珠样品的化学成分、拉曼光谱、UV-NIS反射光谱特征均发生了不同程度的变化。其化学成分以相对富Cu和Pb、贫K为特征;1 276 cm-1处的拉曼谱峰红移至1 371 cm-1附近,1 583 cm-1处的拉曼谱峰则蓝移至1 545 cm-1附近,663 cm-1处的拉曼谱峰随之消失;在可见光波长范围内,c带(697 nm)的相对吸收强度骤减,a带向长波方向红移并与b带组合成一宽大舒缓的吸收谱带。初步证实,巧克力珍珠样品的颜色与其黑色素内共轭双键电子跃迁之间尚无直接的内在联系,主要归因于塔希提棕黑色珍珠内存在的钾色素蛋白经热变异作用所致。     

Visible-light-Mediated TiO2 photocatalysis of fluoroquinolone antibacterial agents

This study reports on the photocatalytic transformation of fluoroquinolone antibacterial agents (ciprofloxacin, enrofloxacin, norfloxacin, and flumequine) in aqueous titanium dioxide (TiO2) suspensions irradiated with ultraviolet (UV; lambda > 324 nm) or visible light (lambda > 400, > 420, or > 450 nm). Visible-light-mediated fluoroquinolone degradation is unexpected from direct photolysis or established TiO2 band gap photoexcitation mechanisms, which both require UV light. Visible-light-mediated photocatalysis requires an appropriate conduction band electron acceptor (e.g., O2, BrO3-), but is not dependent upon hydroxyl radical, superoxide, or other reactive oxygen species generated upon TiO2 band gap excitation. The process slows considerably when fluoroquinolone adsorption is inhibited. Whereas fluoroquinolone decomposition in UV-irradiated TiO2 suspensions is accompanied by mineralization, no changes in dissolved organic carbon occur during visible-light-photocatalyzed degradation. Results are consistent with a proposed charge-transfer mechanism initiated by photoexcitation of surface-complexed fluoroquinolone molecules. Complexation to the TiO2 surface causes a red shift in the fluoroquinolone absorption spectrum (via ligand-to-metal charge transfer), enabling photoexcitation by visible light. Fluoroquinolone oxidation then occurs by electron transfer into the TiO2 conduction band, which delivers the electron to an adsorbed electron acceptor. The lack of organic carbon mineralization indicates formation of stable organic byproducts that are resistant to further degradation by visible light. In UV-irradiated TiO2 suspensions, the charge-transfer mechanism acts in parallel with the semiconductor band gap photoexcitation mechanism.     

助熔剂法合成尖晶石的宝石学特征研究

采用常规的宝石学研究方法以及电子探针、紫外-可见分光光度计、傅里叶变换红外光谱仪和宝石阴极发光光谱仪等现代测试仪器, 对助熔剂法合成尖晶石的宝石学特征进行了全面分析, 并与天然尖晶石进行了对比. 助熔剂法合成尖晶石的晶体形貌特征和包裹体特征以及紫外-可见吸收光谱、红外光谱和阴极发光特征为其鉴定提供了可靠的依据.     

Fading of artificial hair colour and its prevention by photofilters

Fading of artificial hair colour has been investigated by simulating actual usage conditions through exposure to artificial radiation in a weatherometer, with 0.35 mW (m(2)nm)(-1) at 340 nm, for 16-48 h, and by periodical washing. Hair colour was produced by using commercial two-part, permanent hair dyes with light auburn, medium auburn and dark auburn shades. Formulations based on red couplers, such as 4-amino-2-hydroxytoluene and 1-naphthol, as well as primary intermediates, such as 1-hydroxyethyl-4,5-diamino pyrazole sulphate, were employed. Results indicate that the extent of fading, as measured by the total colour change parameter, dE, is greatest for coloured hair subjected to both irradiation and shampooing, and significantly smaller for hair undergoing only irradiation or washing. Colour loss has been also found to be dependent upon the hair type employed, with coloured natural white and bleached hair undergoing much greater change than coloured brown hair. It has been also shown that hair colour based on pyrazole intermediates displayed the deepest fading as a result of shampooing (dE 4-6 after 10 shampooings) and irradiation per shampooing (dE 14-16 after 32 h of light exposure and four shampooings). The contribution of UV light (UVB + UVA) to the artificial hair-colour loss was found experimentally to be dependent upon the irradiation dose and varied from 63% at 16 h of irradiation time to 27% at 48 h of light exposure. The theoretical extent of photoprotection by a formulation was assessed by calculating the percentage of UV light it attenuates in the wavelength range from 290 to 400 nm. The results indicate that UVB photofilters, such as octyl methoxy cinnamate, absorb <25% of the total UV irradiation at concentrations as high as 30 mg (g hair)(-1). UVA absorbers were found to be more effective, with benzophenone-3 and benzophenone-4 absorbing about 40% of UV at the same concentration. Corresponding experimental data were in reasonable agreement with the theoretical predictions. The data are also presented for colour protection with treatments containing two photo-absorbers: benzophenone-3-ZnO; benzophenone-4-ZnO; octyl methoxy cinnamate-ZnO; and dimethylpabaimidopropyl laurdimonium tosylate-benzophenone-3.     

纳米金溶胶形成过程的可见光吸收光谱研究

利用紫外 可见吸收光谱研究了金溶胶的形成过程,制备了10～50nm不同粒径的金溶胶,研究了不同粒径金溶胶的可见吸收光谱变化和分散稳定性.研究结果表明:平均粒径为14nm的金溶胶在生成的初级阶段,首先形成大的团状聚集体,随反应时间的延长,紫外吸收降低,可见光吸收逐步增强,最大吸收波长逐渐向短波方向蓝移,在反应时间为5min左右时形成稳定分散的金胶.随着粒径的增大,反应过程加快,金溶胶的分散稳定性显著降低.金溶胶的可见吸收光谱还具有一定的尺寸效应,在平均粒径大于25.1nm时,最大吸收峰值和峰宽随粒径的增大而增大;当平均粒径小于25.1nm时最大吸收峰值和峰宽随粒径的减小而增大.