5α-雄甾烷-3,17二-酮在一元溶剂中的红外光谱

在20种不同纯有机溶剂中,研究了5α-雄甾烷-3,17-二酮C3位和C17位羰基的红外光谱。将其羰基伸缩振动频率分别与经验溶剂参数如溶剂接受数AN、Brownstein的溶剂参数S和Schleyer线性自由能方程参数G值进行了相关分析。结果表明,C3位C=O在一元溶剂体系中出现2种谱带,而C17位C=O则出现3种谱带。羰基伸缩振动频率位移与AN值、G值具有较好的线性相关性,而在非醇溶剂中与S值线性相关较差。采用简单化合物丙酮分别对溶剂硝基苯、乙腈、二氯甲烷和氯仿的S值进行修正,并将复杂甾酮化合物5α-雄甾烷-3,17-二酮的羰基红外频率与S修正值进行线性分析,相关性良好。     

西沙仙掌藻Halimeda Xishaensis的次级代谢产物

从采自西沙永兴岛的西沙仙掌藻Halimeda Xishaensis样品中分离鉴定了4个单羟基甾醇,5-烯-3α-胆甾醇(1),5-烯-3β-麦角甾醇(2),豆甾醇(3),β-谷甾醇(4)和4个单体化合物,1-正二十三碳酸甘油酯(5),豆甾-4-烯-3β,6β-二醇(6),N-(1-羟甲基-2-羟基-3E-十五碳烯)-正二十七酰胺(7)和1个丁四醇(8)。     

利用NMR技术测定两个新倍半萜醇酯化合物的结构s

报道了从苦皮藤叶中得到的两个新倍半萜醇酯化合物.利用NMR和2D NMR技术测得它们的化学结构分别为1β-苯乙烯酰氧基,9β-(2-羟基)-异丁酰氧基,2β,6α,8α,15-四乙酰氧基-4α-羟基-β-二氢沉香呋喃和1β-苯甲酰氧基,9β-(2-羟基)-异丁酰氧基,2β,6α,8α,     

利用NMR技术测定两个新倍半萜醇酯化合物的结构

报道了从苦皮藤叶中得到的两个新倍半萜醇酯化合物.利用NMR和2DNMR技术测得它们的化学结构分别为1β-苯乙烯酰氧基,9β-(2-羟基)-异丁酰氧基,2β,6α,8α,15-四乙酰氧基-4α-羟基-β-二氢沉香呋喃和1β-苯甲酰氧基,9β-(2-羟基)-异丁酰氧基,2β,6α,8α,15-四乙酰氧基-4α-羟基-β-二氢沉香呋喃.并对其¹H和¹³C NMR信号进行了全归属.     

2(1H)喹啉酮化合物及其开环衍生物的13C NMR研究

本文报道了16种2(1H)喹啉酮及其开环衍生物的碳谱研究,归属了取代喹啉酮母核骨架及侧链上每个碳原子的化学位移,并就卤素取代对母核骨架碳的化学位移影响规律进行了探讨.文中所有化合物的核磁数据迄今未见文献报道.     

5-羟基-7,4′-二甲氧基二氢黄酮分子结构的理论计算研究

分别应用HartreeFock从头算方法和B3LYP密度泛函方法从黑沙蒿中分离得到的5羟基7,4′二甲氧基二氢黄酮分子的几何构型进行优化,并采用规范不变原子轨道GIAO法,进行核磁共振化学位移计算,得到其两种构型的结构参数和NMR化学位移值,并对理论计算值与实验值的误差进行了统计分析.由计算结果推测该化合物分子结构中C(2)上的H在β位,即C(2)的绝对构型为S型.     

中药水团花(Adina pilulifera)中2个色酮苷的NMR化学位移全归属

从采自广东的茜草科植物水团花Adina pilulifera根中分离鉴定出2个色酮苷类化合物Undulatoside B（1）和5,7-二羟基-2-甲基色酮-7-O-β-D-芹糖(1→6)-β-D-葡萄糖(2). 应用2D NMR实验技术对化合物1，2的结构进行了详细研究，并对其¹H和¹³C NMR信号进行了全归属.     

杂环化合物DADDCI在H2O/DMSO溶剂体系中的光谱及聚集行为

化合物6-苯胺基-5H-2,3-二硫杂-5,7-二氮杂环戊二烯并[c,d]茚-1,4-二甲酸二乙酯(DADDCI)是本实验室合成的新型硫氮杂环化合物.通过吸收、荧光光谱,结合理论计算,研究了该化合物在溶剂DMSO/H2O中的结构和聚集性质.结果表明,在DMSO中,化合物的苯环与并噻吩共平面,易形成H-聚集体致使荧光强度相对较弱,在H2O含量为66％-70％时,化合物形成J-聚集体,吸收峰明显红移,从390nm到444nm,伴随着荧光峰强度迅速增强至7倍以上,此时可明显观察到体系呈凝胶状.结构优化证实,化合物与H2O之间的氢键复合物取代与DMSO形成的复合物后,化合物的苯环与主平面之间发生扭转,二面角达86°.形成J-聚集体后,化合物的结构被固定,灵活性降低,分子中亚胺N接受质子的能力及胺N上的氢质子离域能力明显下降,化合物的吸收光谱受酸碱的影响程度明显降低.     

流动注射分光光度法测定煤灰中的微量铀

在稀硝酸介质中,以2-(3-羧基苯偶氮)-7-(4-氯-2-膦酸基苯偶氮)-1,8-二羟基-3,6-萘二磺酸(CPA-mK)作为显色剂,建立了一种测定微量铀的流动注射分光光度法,在最佳实验条件下,该方法的线性范围为0-35mg/L,检出限为0.026mg/L,应用该方法测定煤灰样品中的铀,其相对标准偏差为1.8%-3....     

海洋真菌Gliocladium sp.中的甾体和酚类化合物

从山东乳山采集的海洋真菌Gliocladium sp.中分离得到2个甾体化合物和4个酚类化合物,经1H-NMR、13C-NMR和MS等现代波谱手段鉴定它们的结构分别为:麦角甾-5,7,22E-三烯-3β-醇(1)、23-甲基麦角甾-5,7,22E-三烯-3β-醇(2)、3-羟甲基苯酚(3)、4-甲基-1,2-二苯酚(4)、4-(2-羟乙基)苯酚(5)、2-羟基-6-甲基苯甲酸(6)。     

海洋真菌Penicillium sp.中的环二肽类化合物

从南海采集的海泥中分离得到的海洋真菌Penicillium sp.中分离得到3种环二肽类化合物。通过理化性质和波谱数据分析鉴定了3种化合物的结构。它们分别是3-异丁基-6-异丙基哌嗪-2,5-二酮(1)、3-另丁基-6-异丁基哌嗪-2,5-二酮(2)、3-另丁基-6-异丙基哌嗪-2,5-二酮(3)。     

Physical Explanation on Designing Three Axes as Different Resolution Indexes from GRACE Satellite-Borne Accelerometer

The GRACE Earth＇s gravitational field complete up to degree and order 120 is recovered based on the same and different three-axis resolution indexes from satellite-borne accelerometer using the improved energy conservation principle. The results show that designing XA1（2） as low-sensitivity axis （3 × 10^-9 m/s^2） of accelerometer and designing YA1（2） and ZA1（2） as high-sensitivity axes （3 × 10^-10 m/s^2） are reasonable. The physical reason why the resolution of XA1（2） is one order of magnitude lower than YA1（2） and ZA1（2） is that non-conservative forces acting on GRACE satellites are mainly decomposed into YA1（2） and ZA1（2） in the orbital plane. Since XA1（2） is not orthogonal accurately to orbital plane during the development of accelerometer, the measurement of XA1（2） can not be thrown off entirely, but be reduced properly.     

Solar radiation pressure and deviations from Keplerian orbits

Newtonian gravity and general relativity give exactly the same expression for the period of an object in circular orbit around a static central mass. However, when the effects of the curvature of spacetime and solar radiation pressure are considered simultaneously for a solar sail propelled satellite, there is a deviation from Kepler's third law. It is shown that solar radiation pressure affects the period of this satellite in two ways: by effectively decreasing the solar mass, thereby increasing the period, and by enhancing the effects of other phenomena, potentially rendering some of them detectable. In particular, we consider deviations from Keplerian orbits due to spacetime curvature, frame dragging from the rotation of the sun, the oblateness of the sun, a possible net electric charge of the sun, and a very small positive cosmological constant.     

On the quantum super Virasoro algebra

The quantum super-algebra structure on the deformed super Virasoro algebra is investigated. More specifically we established the possibility of defining a nontrivial Hopf super-algebra on both one and two-parameters deformed super Virasoro algebras.     

Physical Explanation of Influence of Twin and Three Satellite Formation Mode on the Accuracy of Earth's Gravitational Field

The simulated results of the influence of twin and three satellite formation mode on the accuracy of GRACE Earth＇s gravitational field are interpreted from the viewpoint of physics. Because the effective satellite observation information of Earth＇s gravitational field recovery from three-satellite formation mode is only one time more than that of twin satellites, the improvement of the accuracy of Earth＇s gravitational field is far lower than one order of magnitude based on the simple two-times differences between three satellites. Three efficient ways of improving largely the accuracy of measurement of the Earth＇s gravitational field in the future international satellite gravity measurement programme, including proper decrease of satellite orbital altitude, the increase of accuracy from key payloads and an innovation of satellite observation mode are proposed.     

近红外光谱技术在小麦条锈病菌和叶锈病菌定性识别和定量测定中的应用

利用近红外光谱技术结合定性偏最小二乘法(DPLS)和定量偏最小二乘法(QPLS)分别实现了小麦条锈病菌和叶锈病菌的定性识别和定量测定。获取两种锈菌单一夏孢子样品各50个以及条锈病菌纯度为2.5%~100%的混合样品120个。采集样品光谱后,将两类样品均按2∶1的比例分为建模集和检验集,在4 000~10 000cm-1内采用内部交叉验证法建模。散射校正预处理方法下、主成分数为3时,定性识别模型的建模集和检验集识别准确率均为100.00%。"极差归一+散射校正"预处理方法下、主成分数为6时,定量测定模型建模集的决定系数(R2)、校正标准差(SEC)、平均相对误差(AARD)分别为99.36%,2.31%,8.94%,检验集的R2、预测标准差(SEP)、AARD分别为99.37%,2.29%,5.40%。结果表明,利用该方法对这两种锈菌定性和定量分析是可行的。本研究为植物病原菌的定性识别和定量分析提供了一种基于近红外光谱技术的新方法。     

超声辅助法提取刘寄奴黄酮类化合物的工艺

采用超声辅助法提取刘寄奴中的黄酮类化合物,通过单因素试验和正交试验,研究了超声辅助法提取条件(超声波功率、乙醇体积分数、提取温度、提取时间)对刘寄奴黄酮类化合物提取率的影响。结果表明,刘寄奴黄酮类化合物的最佳提取工艺条件为:超声波功率200W、乙醇体积分数80%、提取温度40℃、提取时间45min,在此工艺条件下刘寄奴黄酮类化合物的提取率可达63.27mg/g。     

The new matrix and the polarization state of the transmitted light through the cholesteric liquid crystal

The cholesteric liquid crystal can be regarded as a multilayer that consists of many layer uniaxial thin films that exhibit optical rotation. For the convenient discussion of the polarization states of the transmitted wave through a cholesteric liquid crystal, a new 2×2 matrix is given, in which the matrix element is changed into the complex exponential. Here we discuss the treatment process of this method in detail and its role in the investigation of the polarization states. Using this method we easily study the polarization states of the transmitted wave. The calculated results show that the polarization states of wave will be changed when it propagates along the cholesteric liquid crystal.     

Tunnelling Effect of Two Horizons from a Gibbons--Maeda Black Hole

We study the thermal characters of the inner horizon of a Gibbons-Maeda black hole. In order to satisfy the Nernst theorem of the third law, the entropy of the black hole with two horizons must depend not only on the area of the outer horizon but also on the area of the inner horizon. Then the temperature of the inner horizon is calculated. Lastly, the tunnelling effect including the inner horizon of a Gibbons-Maeda black hole is investigated. We also calculate the tunnelling rate of the outer horizon Г＋ and the inner horizon Г_. The total tunnelling rate Г should be the product of the rates of the outer and inner horizon, Г =Г＋ · Г_. It is found that the total tunnelling rate is in agreement with the Parikh＇s standard result, Г→ exp（ ASBH ）, and there is no information loss.