对三角形面积表示法(Triangle Area Representation,TAR)描述图形进行讨论,分析TAR-AVG(TAR Average Filtering)和TAR-MED(TAR Median Filtering)的原理.用TAR-AVG衡量图形的外凸与内凹特性,用TAR-MED获得边界曲率信息.结合两种方法的...对三角形面积表示法(Triangle Area Representation,TAR)描述图形进行讨论,分析TAR-AVG(TAR Average Filtering)和TAR-MED(TAR Median Filtering)的原理.用TAR-AVG衡量图形的外凸与内凹特性,用TAR-MED获得边界曲率信息.结合两种方法的滤波特性,提出TAR-MAMF(TAR Median Average Mixed Filtering)方法,对滤波结果用直方图表示,从直方图输出结果中提取有效的特征参数,确定图形中凹点和凸点的数量以及所在边界的位置,实现图形拐点识别.实验证明,TAR-MAMF方法对图形拐点的定位准确、有效.展开更多
The capillary electrophoretic separation of Fe 2+ , Co 2+ , Zn 2+ and Ni 2+ in a phosphate buffer solution by complexing with 4 (2 thiazolylazo)resorcinol was investigated. The influences of some crucial parameters th...The capillary electrophoretic separation of Fe 2+ , Co 2+ , Zn 2+ and Ni 2+ in a phosphate buffer solution by complexing with 4 (2 thiazolylazo)resorcinol was investigated. The influences of some crucial parameters that included chelating ligand in the electrophoretic running buffer and sample solution, pH value and concentration of buffer were examined. Under optimum conditions (10mmol·l -1 NaH 2PO 4 Na 2HPO 4 buffer containing 1×10 -4 mol·l -1 TAR, pH 7 5), a baseline separation of these metals was accomplished within 3 min. The detection limits (S/N=3) ranged from 0 013—0 14 μg·ml -1 . The method was applied to analyze trace metal ions in the environmental samples.展开更多
Tat, an essential human immumodeficiency virus type 1 protein interacts with the transactivation response element(TAR) and stimulates transcription from the viral long-terminal repeat(LTR). Blockage of Tat-TAR interac...Tat, an essential human immumodeficiency virus type 1 protein interacts with the transactivation response element(TAR) and stimulates transcription from the viral long-terminal repeat(LTR). Blockage of Tat-TAR interaction halts viral transcription and hence replication. In recent years a numbe of studies have suggested various chemicals and /or genetic inhibitors targeting TAR RNA for inhibition of Tat-activated transcription. Here, we report these research works.展开更多
TAR DNA结合蛋白43(TAR DNA-binding domain protein 43,TDP-43)是一种高度保守、广泛表达的核蛋白。如今发现TDP-43在大多数神经退行性疾病如阿尔茨海默症患者中表达,为神经退行性疾病相关的标记蛋白。本文从目前国内外的研究现状出发...TAR DNA结合蛋白43(TAR DNA-binding domain protein 43,TDP-43)是一种高度保守、广泛表达的核蛋白。如今发现TDP-43在大多数神经退行性疾病如阿尔茨海默症患者中表达,为神经退行性疾病相关的标记蛋白。本文从目前国内外的研究现状出发,围绕TDP-43的表达与脑损伤的相关性,在对TDP-43生物学特性认识的基础上,着重探讨TDP-43在急、慢性颅脑损伤中的特殊表达与作用,从而探索TDP-43在法医病理学中确定死亡原因、判定致伤致残情况的可行性。展开更多
Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ...Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ET-HR was first brominated at 30 or 200℃,and then heat-treated at 350℃to enable the dehydrobromination/polycondensation reactions.GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3-to 6-ring aromatic species with a considerable aliphatic chain content.Compared with thermal condensation alone,such a two-step method increased the softening point of the pitches from 152 to 264℃with a yield in the range of 62 wt.%-67 wt.%and a coking value in the range of 57 wt.%-77 wt.%,depending on the bromination temperature and the bromine content.Structural characterization of the as-prepared pitches by elemental analysis,1H NMR,FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobrominatio/polycondensation.All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800℃.展开更多
B3LYP/6-31G(d,p) method was used to investigate the catalytic cracking mechanism of biomass tar model compound.Phenol,toluene and benzene were selected as the tar model compounds and CaO was selected as the catalyst.T...B3LYP/6-31G(d,p) method was used to investigate the catalytic cracking mechanism of biomass tar model compound.Phenol,toluene and benzene were selected as the tar model compounds and CaO was selected as the catalyst.The pathways of tar compound radical absorbed by CaO were determined firstly through comparing enthalpy changes of the absorption,and then Mulliken population changes were analyzed.The results show that the absorption of tar model compound radical and CaO is an exothermic reaction.Formation of C—O—Ca is more easily than that of C—Ca—O and formation of Caromatic—Caromatic—Ca—O is more easily than that of Caromatic—C(O)—Ca—O.The C—C bond Mulliken populations in tar model compound radicals are reduced by 11.9%,10.5% and 15.5% in the case of a hydrogen atom removed,and those are 15.7%,14.3% and 16.3% in the case of two hydrogen atoms removed through the absorption of CaO.Catalytic ability of CaO acting on the tar model compound is in an order of phenol>benzene>toluene.展开更多
文摘对三角形面积表示法(Triangle Area Representation,TAR)描述图形进行讨论,分析TAR-AVG(TAR Average Filtering)和TAR-MED(TAR Median Filtering)的原理.用TAR-AVG衡量图形的外凸与内凹特性,用TAR-MED获得边界曲率信息.结合两种方法的滤波特性,提出TAR-MAMF(TAR Median Average Mixed Filtering)方法,对滤波结果用直方图表示,从直方图输出结果中提取有效的特征参数,确定图形中凹点和凸点的数量以及所在边界的位置,实现图形拐点识别.实验证明,TAR-MAMF方法对图形拐点的定位准确、有效.
文摘The capillary electrophoretic separation of Fe 2+ , Co 2+ , Zn 2+ and Ni 2+ in a phosphate buffer solution by complexing with 4 (2 thiazolylazo)resorcinol was investigated. The influences of some crucial parameters that included chelating ligand in the electrophoretic running buffer and sample solution, pH value and concentration of buffer were examined. Under optimum conditions (10mmol·l -1 NaH 2PO 4 Na 2HPO 4 buffer containing 1×10 -4 mol·l -1 TAR, pH 7 5), a baseline separation of these metals was accomplished within 3 min. The detection limits (S/N=3) ranged from 0 013—0 14 μg·ml -1 . The method was applied to analyze trace metal ions in the environmental samples.
文摘Tat, an essential human immumodeficiency virus type 1 protein interacts with the transactivation response element(TAR) and stimulates transcription from the viral long-terminal repeat(LTR). Blockage of Tat-TAR interaction halts viral transcription and hence replication. In recent years a numbe of studies have suggested various chemicals and /or genetic inhibitors targeting TAR RNA for inhibition of Tat-activated transcription. Here, we report these research works.
文摘Homogeneous isotropic pitches with high softening points were prepared from vacuum-distilled heavy residue ethylene tar(ET-HR)by a two-step method of bromination and subsequent dehydrobromination/polycondensation.The ET-HR was first brominated at 30 or 200℃,and then heat-treated at 350℃to enable the dehydrobromination/polycondensation reactions.GC/MS and LDI TOF/MS spectra indicated that the ET-HR was mainly composed of compounds containing 3-to 6-ring aromatic species with a considerable aliphatic chain content.Compared with thermal condensation alone,such a two-step method increased the softening point of the pitches from 152 to 264℃with a yield in the range of 62 wt.%-67 wt.%and a coking value in the range of 57 wt.%-77 wt.%,depending on the bromination temperature and the bromine content.Structural characterization of the as-prepared pitches by elemental analysis,1H NMR,FT-IR and LDI-TOF/MS showed increased aromatization and polymerization of the precursor during the dehydrobrominatio/polycondensation.All the homogeneous isotropic pitches showed an ability to transform into an anisotropic texture after coking at 800℃.
基金Project(51276023)supported by the National Natural Science Foundation of China
文摘B3LYP/6-31G(d,p) method was used to investigate the catalytic cracking mechanism of biomass tar model compound.Phenol,toluene and benzene were selected as the tar model compounds and CaO was selected as the catalyst.The pathways of tar compound radical absorbed by CaO were determined firstly through comparing enthalpy changes of the absorption,and then Mulliken population changes were analyzed.The results show that the absorption of tar model compound radical and CaO is an exothermic reaction.Formation of C—O—Ca is more easily than that of C—Ca—O and formation of Caromatic—Caromatic—Ca—O is more easily than that of Caromatic—C(O)—Ca—O.The C—C bond Mulliken populations in tar model compound radicals are reduced by 11.9%,10.5% and 15.5% in the case of a hydrogen atom removed,and those are 15.7%,14.3% and 16.3% in the case of two hydrogen atoms removed through the absorption of CaO.Catalytic ability of CaO acting on the tar model compound is in an order of phenol>benzene>toluene.
