傅里叶变换红外光谱法对珍珠粉和贝壳粉的研究

通过FTIR比较研究了淡水养殖珍珠的珍珠粉和贝壳粉样品原样、角壳蛋白以及250、400℃和750℃热处理2h后红外光谱的差异。结果表明,珍珠粉和贝壳粉的主要成分均为文石型碳酸钙,并含有少量有机质和水分。2种粉末角壳蛋白红外吸收峰型基本相似,仅在2113.3cm-1处存在差异。250℃加热后,两者成分结构基本没有变化;400℃加热后2种粉末有机物完全分解,珍珠粉文石碳酸钙的晶型部分转变为方解石型,而贝壳粉碳酸钙已完全转化为方解石型;750℃加热后两者的碳酸钙晶形均已完全转化为方解石型,且有大量碳酸钙分解为氧化钙。     

基于拉曼光谱和DCGAN数据增强的珍珠粉掺伪检测研究

珍珠粉和珍珠层粉化学成分相似,但是珍珠层粉的药用价值远低于珍珠粉,并且珍珠层粉制备容易,成本底,常被不法商家用于冒充或掺入珍珠粉中流入市场,谋取利益.因此,对珍珠粉掺伪鉴别和纯度检测具有重要的意义.采用激光拉曼光谱结合深度学习研究珍珠粉掺伪快速鉴别和纯度分析.将纯珍珠粉和珍珠层粉按一定比例混合,制成珍珠粉质量百分数分别...     

金色海水养殖珍珠异常的UV-Vis反射与FTIR光谱特征

采用紫外-可见(UV-Vis)反射光谱对天然与改色处理的金色海水养殖珍珠进行了谱图对比性研究,并进一步探究了上述天然与经改色处理金珠中外层的珍珠层及内核中文石型碳酸钙的ν₃,ν₁,ν₂和ν₄特征吸收峰位的频率改变特征。 结果表明：(1)基于金珠样品的UV-Vis反射谱图的测试,天然金珠样品由于表面微结构的差异,同一颗天然金珠的UV-Vis反射光谱存在一定的差异性。 同时,依据改色处理金珠的UV-Vis反射谱图的吸收峰的峰位及其谱图特征,首次将目前较常见的改色处理金珠归纳为四类。 (2)天然的或者经改色处理的金珠的外层珍珠层中的文石ν₂振动频率相对内核中文石的ν₂振动频率而言,前者出现明显的蓝移特征。 但两者中文石的ν₃, ν₁, ν₄振动频率则表现出一致性, 且与合成文石的相关谱带频率一致。 此外,天然与改色处理的金珠珍珠层中文石的红外特征吸收峰峰位一致,结果表明改色处理工艺对珍珠层中文石的晶体结构无直接影响。     

傅里叶变换红外光谱法研究核辐照对螺旋藻粉成分的影响

采用红外光谱法对经不同剂量核辐照的螺旋藻粉进行了对比研究,比较了它们的红外光谱的异同。螺旋藻粉的红外光谱主要由蛋白吸收带及碳水化合物的吸收带组成,一定辐照剂量处理的螺旋藻粉成分的化学结构并未发生变化,部分成分含量发生了变化。表明辐照可杀灭螺旋藻粉中污染微生物和各种水生寄生虫卵,同时利用红外光谱法可以快速检测螺旋藻粉样品是否经过辐照处理。随着辐照剂量的增加样品某些种类的蛋白质含量随之减少了。这与文献[1]研究得到的结果是一致。螺旋藻粉的红外光谱的特征峰（1654、1452及1240cm-1）与啤酒酵母的蛋白质红外光谱的特征峰位相同及峰形非常相似,表明螺旋藻粉和啤酒酵母中的蛋白质的化学结构可能很相似。     

共聚焦拉曼光谱在贻贝介壳探测中的应用

贻贝是广泛分布于全球水域的物种,从近海海域到深海热液、冷泉等极端环境。贻贝分泌碳酸钙矿物形成介壳保护软体组织,介壳是一种天然纳米复合材料,具有优异的力学性能,在生物材料、组织工程以及仿生学等方面具有很好的应用前景,已经成为国内外研究热点之一。拉曼光谱是一种非破坏、非接触及多组分同时测试的检测技术,可以提供矿物成分信息。利用共聚焦显微激光拉曼技术对不同环境下(台西南冷泉繁茂区、 Desmos热液区、实验室养殖及大连近海海域)生长的贻贝介壳进行检测,得到四种环境中生存的贻贝介壳珍珠层的拉曼光谱和介壳横截面局部区域的线扫趋势图及二维拉曼成像图。基于实验结果得到以下结论,四种环境中生存的贻贝介壳的棱柱层和珍珠层矿物为碳酸钙,其中棱柱层矿物组成均为方解石,拉曼测试方解石特征峰位于711和281 cm~(-1)附近,而介壳珍珠层虽然主要为碳酸钙,但不同环境下生长的贻贝珍珠层的矿物组成存在一定差别:大连近海贻贝珍珠层矿物为文石,拉曼测试文石特征峰位于706和206 cm~(-1)附近,结晶程度差。热液区生长以及实验室养殖贻贝珍珠层矿物也为文石,特征峰位于706和206 cm~(-1)附近,但结晶程度相对较好。台西南冷泉繁茂区贻贝珍珠层主要为文石(706和206 cm~(-1)),并含少量方解石,拉曼测试方解石特征峰位于711和281 cm~(-1)附近。通过对比四种环境中贻贝介壳的矿物组分以及相对分布,结合生存环境的差异,认为介壳矿物组成差异是贻贝应对深海冷泉、热液不同理化环境的一种环境适应机制。测试结果表明贻贝生长环境压力对珍珠层矿物组成有较大影响。研究表明共聚焦显微拉曼光谱是一种快速、高效的用于研究不同环境下生存的贻贝的介壳矿物组成的技术手段。这为研究深海贻贝生命过程与适应机制提供了重要的参考资料。     

三七及其伪品二维相关红外光谱法的鉴别研究

采用红外光谱法和二维相关红外光谱技术,对三七及其伪品姜黄、白术进行了快速无损的鉴别研究。结果表明:在红外谱图上,三七及其伪品姜黄、白术均有黄酮、芳香类和糖苷类成分的特征吸收峰,但存在一定的差异。在二维红外谱图上,根据三者的自动峰的位置、数量和峰的相对强度的差异,可快速将三者鉴别出来。因此,常规红外光谱法和二维相关红外光谱技术相结合可实现三七的真伪鉴别。     

FTIR直接鉴定紫苏子及其伪品的研究

本文首次采用傅里叶变换红外光谱法的单次反射采样技术,直接、快速、准确地测定了种子类中药材紫苏子及其伪品的红外光谱。结果表明:种子类中药材紫苏子及其伪品的种仁和皮层由于所含化学成分的不同,其红外光谱的吸收的位置和强度均有明显差异,发现紫苏子与白苏子为同种植物,野生紫苏子则有所区别,且紫苏子与其伪品石荠苧、苏州荠苧及疏花荠苧的红外光谱吸收差别较大。根据红外特征吸收能够达到中药材的真伪鉴别及种类认定的目的。该方法具有直接、快速、准确、无需制样等特点。     

半夏及其伪品天南星的近红外漫反射快速无损鉴别

利用近红外漫反射光谱法,结合聚类分析和相似度计算,对不同产地半夏药材及其伪品天南星进行了快速无损鉴别研究。近红外光谱图的聚类分析和相似度计算结果一致,为中药的产地、真伪鉴别分析提供了一种新的方法,具有较好的应用价值。     

用傅立叶变换红外光谱法研究核辐照对三七粉成分的影响

本文采用红外光谱法对经不同剂量核辐照的三七粉进行了对比研究, 比较了它们红外光谱的异同。三七粉的红外光谱主要由淀粉吸收带及碳水化合物的吸收带组成, 低辐照剂量(低于15 kGy)处理的三七粉组成成分的化学结构及含量几乎未发生变化; 较高辐照剂量(高于18 kGy)处理的三七粉组成成分中少数成分的化学结构及含量可能已经发生了变化。表明采用适当核辐照剂量杀灭三七粉中污染微生物和各种寄生虫卵是可取的。辐照剂量高于15 kGy后, 糖类(主要是多糖、庶糖)增加, 增加的糖可能是淀粉转化而来的。     

二维相关红外光谱技术快速鉴别三七及其伪品

采用红外光谱法并结合二维相关红外光谱技术,对三七及其伪品姜黄、白术进行了快速无损的鉴别研究。在一维红外谱图上,三七及其伪品姜黄、白术中的黄酮成分、芳香成分和糖苷类成分的特征吸收峰均存在一定的差异。在1200~700cm~(-1)波数范围内,三七、姜黄均出现淀粉的特征峰,而白术没有显示淀粉的特征峰,根据各药材的红外光谱中淀粉的特征峰的相对强度,可判断三七中淀粉的相对含量要高于姜黄,而白术药材中不含淀粉。在二维红外谱图上,根据三者的自动峰的位置、数量和峰的相对强度的差异,可快速将三者鉴别出来。因此,常规红外光谱法和二维相关红外光谱技术相结合可实现三七的真伪鉴别。     

Combination of FTIR and SEM for Identifying Freshwater-Cultured Pearls from Different Quality

The freshwater-cultured pearl (Chamberlainia hainesiana species) is an organic gemstone mainly composed of calcium carbonate mineral including calcite, aragonite and vaterite phases. Generally, the quality of freshwater-cultured pearl is based on its luster. The high luster pearl is full of the aragonite phase without vaterite phase. On the other hand, the low luster pearl consists of aragonite and vaterite phases. These data could be proved by the Fourier Transform Infrared (FTIR) spectroscopy combined with the scanning electron microscopy (SEM). As the results, the high luster pearl similarly shows the FTIR spectrum of aragonite phase, and also, it shows the hexagonal shape of aragonite for the SEM image. On the other hand, the FTIR spectrum of low luster pearl has been pointed to the mixture component among aragonite and vaterite phases, and based on the SEM image; the irregular form is also interpreted to the mixture of aragonite and vaterite phases. This research concludes that the quality of freshwater-cultured pearls can be identified by the combination data of FTIR spectra and SEM images. These techniques are suitable for applied gemology.     

Identification and spectra–structure determination of soil minerals: Raman study supported by IR spectroscopy and X‐ray powder diffraction

Raman and IR spectroscopy were used for the characterization of several minerals in morphologically similar vertisol sequences from Kiževak (Serbia). It helped us to establish the surface layer transition going from calcic vertisols (containing gypsum and calcite) to calcimagnesic vertisols (containing aragonite, magnesium‐calcite and dolomite) derived from peridotite and serpentinite. The observed band positions are found to be solely characteristic for each carbonate mineral and are used to discuss the main structural features of carbonates and sulfates present in the studied soil. It was found that the dolomite, calcite and aragonite concretions are present in the deepest layer of the soil, whereas the gypsum is found in the topsoil. The identification was confirmed of the carbonates having calcite and aragonite structure, and the representative from the sulfate group (gypsum) was confirmed by X‐ray powder diffraction. Copyright © 2009 John Wiley & Sons, Ltd.     

利用FTIR对海水养殖珍珠中磷的存在形式的研究初探

利用高分辨率傅里叶变换红外光谱技术(FTIR)对比研究了海水养殖珍珠粉末在160 ℃温度下热处理前后的变化。研究发现：海水养殖珍珠在热处理前、后的矿物相都主要为文石型碳酸钙(CaCO₃);但在160 ℃温度下热处理一段时间后,海水养殖珍珠的红外光谱发生了明显的变化,出现了文石以外的吸收峰,并随着热处理时间的增加,这些吸收峰有增强的趋势。而样品的差热分析(DTA)结果证明：在25～160 ℃温度范围内,海水养殖珍珠除发生吸附水的脱失外,无其他热反应发生(见图1)。也就是说明,海水养殖珍珠中除文石外应还含有其他物相存在。该物相经红外光谱分析证实为碳羟磷灰石。相同样品的X衍射(XRD)结果也与这一结论相吻合,证明海水养殖珍珠中存在碳羟磷灰石。     

氮化硅粉料的漫反射傅里叶变换红外光谱研究

利用漫反傅里叶变换红外（DRIFT）光谱技术，研究了氮化硅粉示纯样品和KBr稀释后样品的漫反射光谱的差别，并利用氮化硅粉末纯样品的DRIFT谱图，研究了四种商业氮化硅粉料初始及锻烧后的表面特征，研究发现，与KBr稀释的样品相比，氮化硅粉末纯样品的漫反射红外光谱在1190cm^-1波数处出现了对应于颗粒表面Si-O振动的尖锐强峰。所研究的四种商业氮化硅原始料漫反射光普有很大的差异，煅烧处理后粉料表面的氨基基因和Si-H消失，Si-O和Si-OH的数量显著增加。     

近红外光谱技术的乳粉品牌溯源研究

采用近红外光谱漫反射模式,结合简易分类技术(soft independent modeling of class analogy, SIMCA)对不同品牌乳粉进行了分类溯源研究。实验共采集了四种不同品牌乳粉,包括光明乳粉54组,荷兰乳粉43组,雀巢乳粉33组以及伊利乳粉8组共138组样品的近红外光谱,通过对预处理后的训练集全谱段数据变量进行主成分分析,得出前三个主成分的累积方差贡献率为99.07%。利用SIMCA类建模法建立的乳粉主成分回归模型对预测集乳粉进行分类,研究结果表明,光明乳粉、荷兰乳粉、雀巢乳粉的识别率分别为78%, 75%, 100%,拒绝率分别为100%, 87%, 88%。因此,近红外光谱结合SIMCA建立的模型具备较好的乳粉品牌溯源能力,为快速、准确鉴别乳粉品牌提供了新思路。     

Phase transformations in calcite from electrical impedance measurements

The phase transformation in calcite I-IV-V and calcite ? aragonite have been characterized by electrical impedance measurements at temperatures 600–1200°C and pressures 0.5–2.5?GPa in a piston cylinder apparatus. The bulk conductivity σ has been measured from Argand plots in the frequency range 10⁵–10^?2?Hz in an electric cell representing a coaxial cylindrical capacitor. The synthetic polycrystalline powder of CaCO₃ and natural crystals of calcite were used as starting materials. The transformation temperature T_c was identified from resistivity-temperature curves as a kink point of the activation energy. At pressure above 2?GPa in ordered phase calcite I, the activation energy E _σ is c. 1.05?eV, and in disordered phase calcite V E _σ is c. 0.75?eV. The pressure dependence of T_c for the rotational order–disorder transformation in calcite is positive for pressures <1?GPa and negative for pressures >1?GPa. The transformation boundary of calcite 1–IV is observed only during first heating in samples after a long annealing at low temperatures. The activation energy of calcite I???IV decreases gradually from 1.8 to 1.05?eV with the pressure increase from 0.5 to 2?GPa. The kinetics of calcite ? aragonite transformation has been monitored by measuring a time-variation of the electrical resistance of a calcite sample at 10³?Hz in the stability P-T field of aragonite. The variation of the impedance correlates with the degree of phase transformation, estimated from X-ray powder diffraction studies on quenched products of experiments. The kinetics of calcite ? aragonite transformation may be fitted to the Avrami kinetics with the exponent m???1–1.5.     

Photocatalytic Activity of N-doped TiO2 Photocatalysts Prepared from the Molecular Precursor (NH4)2TiO(C2O4)2

用不同温度控制分解草酸氧钛铵制备N掺杂TiO₂光催化剂．利用XRD、IR、热分析、N₂吸-脱附等温线、XPS、紫外可见漫反射光谱和SEM表征了N-TiO₂光催化剂的结构．400～600 oC焙烧的N-TiO₂光催化剂为纯锐钛矿相,而700 oC焙烧的N-TiO₂光催化剂为锐钛矿和金红石混合相．N掺杂在TiO₂的间隙位使锐钛矿相TiO₂带隙变窄．在光降解甲基橙的反应中,600和400 oC焙烧的N-TiO₂催化剂分别在紫外光和全波长光照射下有最好活性;700 oC焙烧的N-TiO₂催化剂无论在紫外光和全波长光下都表现出最好的比活性,即最高的光量子效率,这可以归因于700 oC焙烧的N-TiO₂光催化剂良好的结晶程度和锐钛矿-金红石异相结的存在．     

Synthesis and characterization of tin oxide (SnO2) nanocrystalline powders by a simple modified sol–gel route

This paper reports the synthesis and characterization of nanocrystalline tin oxide (SnO₂) powders by a simple method using a chitosan–polymer complex solution. To obtain SnO₂ nanocrystalline powders, the precursor was calcined at 500–600 °C in air for 2 h. The phase composition of calcined samples was studied by X-ray diffraction (XRD). The XRD results confirmed the formation of a SnO₂ phase with tetragonal structure. The particle sizes of the powder were found to be 22–23 nm as evaluated by the XRD line broadening method. TEM investigation revealed that the SnO₂ samples consist of crystalline particles of 19–21 nm. The corresponding selected area electron diffraction analysis further confirmed the formation of the tetragonal structure of SnO₂ without any impurity phases. The optical properties of the samples were explored by Fourier transform infrared spectroscopy, optical absorption and Raman studies. The estimated band gaps of the samples were in the range of 3.44–3.73 eV.