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Preliminary studies of acute and sub-chronic toxicity of the aqueous extract of Guibourtia tessmannii(Harms) J.Leonard stem barks (Caesalpiniaceae) in mice and rats 被引量:2
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作者 Noreen Orianna Koumba Madingou Aristide Traore +4 位作者 Alain Souza Marlaine Michelle Boukandou Mounanga Raissa Reine Aworet Samseny Sylvin Ouedraogo Alfred Sababenedyo Traore 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2016年第6期506-510,共5页
Objective: To investigate the toxicity of aqueous extract of Guibourtia tessmannii(Harms) J. Leonard(G. tessmannii) and evaluate its safety.Methods: NMRI mice were used to determine the acute toxicity of G. tessmannii... Objective: To investigate the toxicity of aqueous extract of Guibourtia tessmannii(Harms) J. Leonard(G. tessmannii) and evaluate its safety.Methods: NMRI mice were used to determine the acute toxicity of G. tessmannii.Increasing concentrations of the plant extracts were administered intraperitoneally or by force-feeding. General behavior and death were monitored and recorded daily for 7 days.In order to determine the sub-acute toxicity of the extract, several doses were administered by oral gavage daily for 28 days in adult Wistar rats. Different parameters were assessed including body weight, food and water intake, biochemical parameters and several vital organ weights.Results: LD50 of 328.78 mg/kg was obtained by i.p. route and more than 5 000 mg/kg was obtained in acute toxicity by oral route. In sub-acute toxicity, no significant alteration was observed in body weight or vital organs, food and water intake, and biochemical parameters.Conclusions: The results showed that the aqueous extract of G. tessmannii has low toxicity intraperitoneally and no sub-acute toxicity via oral intake. 展开更多
关键词 Guibourtia tessmannii Stem barks Plant extract HERBAL medicine TOXICITY
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Effect of Drying Conditions on Rheological Properties of Hydrocolloids Gums from <i>Triumfetta cordifolia</i>and <i>Bridelia thermifolia</i>Barks
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作者 Clément Saidou Robert Ndjouenkeu +3 位作者 Denis Roux Jean Bosco Tchatchueng Alain Heyraud Nadia El Kissi 《Food and Nutrition Sciences》 2013年第6期626-631,共6页
Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sa... Triumfetta cordifolia and Bridelia thermifolia are two shrubs from tropical region of Africa. Their gums are traditionally extracted from fresh barks and used in traditional recipes (thickening and aromatization of sauces, improvement of the swelling of maize and bean cakes) and in the process of decantation of traditional beer. In order to valorize these barks in dried form, study of the effect of drying temperature on the rheological properties of their gums was carried out. In this respect, the fresh barks were dried at 40℃, 50℃, 60℃, 70℃ and 80℃ and the viscosity of their extracts was measured. The drying kinetic of the barks showed two falling rate periods represented by two drying constants?k1 and k2. The absolute viscosity of the extracts decreased beyond drying temperatures higher than 70℃ and 80℃respectively for T cordifolia and B. Thermifolia. The decreasing viscosity is attributed mainly to a reorganization of polysaccharide chains. The temperatures range lower than 70℃ could be retained to dry the barks and to extract gums without deteriorating their properties. 展开更多
关键词 barks DRYING Constant Equilibrium Moisture Content GUMS Viscosity
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Lipophilic extractives of the inner and outer barks from six different Pinus species grown in Indonesia 被引量:2
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作者 Masendra Tatsuya Ashitani +1 位作者 Koetsu Takahashi Ganis Lukmandaru 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第5期1329-1336,共8页
The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species(P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis) grown in Indonesia were investigated... The chemical compositions of the dichloromethane extracts of inner and outer barks from six Pinus species(P.elliotii,P.oocarpa,P.caribeae,P.merkusii,P.montezumae,and P.insularis) grown in Indonesia were investigated by GC and GC–MS.Generally,the amounts of extractive contents were higher in the inner bark than in the outer bark except for P.merksuii.Fatty acids,monoterpenes,sesquiterpenes,resin acids,triterpenoids,and steroids were detected and quantified.Inner and outer barks differed not only in content of these compounds but also in their composition.Fatty acids and alcohols were the major classes of lipophilic compounds in the outer bark of P.caribeae, P.insularis,and P.montezumae.Steroids and triterpenoids were the dominant compounds identified in the inner bark of P.elliotii,P.insularis,and P.merkusii.Resin acids were the most abundant group in the inner bark of P.oocarpa whereas monoterpenes and sesquiterpenes were recorded in minor quantities in both bark layers of all species. 展开更多
关键词 Bark extractive LIPOPHILIC Inner bark Outer bark Pinus spp
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^(57)Fe Mssbauer spectroscopic study on the barks of several three species grown in Lanzhou, China
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作者 Wang Hong liang Department of Biology,Lanzhou University, Lanzhou 730000,China Zhao Zhen jie, Li Fa shen Department of Physics,Lanzhou University,Lanzhou 730000,China 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1998年第4期40-42,共3页
Using 57 Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, Ch... Using 57 Fe Mssbauer effect, the chemical states of iron components were investigated for the barks of Platycladus orientalis, Cedrus deodara and Platanus acerifolia sampled from Lanzhou City, China. All bark samples showed two overlapping doublets with large and small quadruple splitting. Only Platycladus orientalis's barks exhibited one sextet. Based on Mssbauer parameters, they were attributed to paramagnetic ferrous, paramagnetic ferric and magnetic iron, respectively. For the sampling site which is about 6 kilometers from Lanzhou Steel Factory, the ratio of ferrous to ferric was higher in the sample of Platanus acerifolia's barks, whereas the barks of Platycladus orientalis and Cedrus deodara gave similar values of this ratio. Platycladus orientalis was the most effective in accumulating iron complexes in barks among the three trees. Platanus acerifolia's barks sampled at Lanzhou Steel Factory's area exhibited higher absolute intensities of iron components and lower ration of ferrous to ferric, indicating that industrial air pollution is a contributing factor in accumulating iron compounds in the tree barks of this region. 展开更多
关键词 Mssbauer spectroscopy iron BARK air pollution.
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Watchdog Barks At Big Bids
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作者 TAN WEI 《Beijing Review》 2008年第12期32-33,共2页
Turmoil caused by major refinancing plans of listed companies in the mainland stock market leads regulators to vow stricter approval processes On March 5,shareholders of Ping An Insurance(Group)Co.of China Ltd. (Ping ... Turmoil caused by major refinancing plans of listed companies in the mainland stock market leads regulators to vow stricter approval processes On March 5,shareholders of Ping An Insurance(Group)Co.of China Ltd. (Ping An)passed a refinancing plan of 120 billion yuan($17 billion)at its first interim meeting of the year with an overwhelming 92 percent in favor. 展开更多
关键词 NASDAQ Watchdog barks At Big Bids
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Solving the puzzle of salicylic acid biosynthesis in plants
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作者 Pei Miao Jian-Min Zhou 《Journal of Genetics and Genomics》 2025年第11期1305-1307,共3页
Originally extracted from willow bark,salicylic acid(SA)provided the structural basis for the synthesis of acetylsalicylic acid(aspirin)in 1897,a milestone that exemplifies the far-reaching biomedical relevance of pla... Originally extracted from willow bark,salicylic acid(SA)provided the structural basis for the synthesis of acetylsalicylic acid(aspirin)in 1897,a milestone that exemplifies the far-reaching biomedical relevance of plant-derived metabolites(Desborough and Keeling,2017).In plants,SA functions as a pleiotropic phytohormone that orchestrates immune reprogramming,serving as a central mediator of both local defense responses and systemic acquired resistance(SAR). 展开更多
关键词 BIOSYNTHESIS acetylsalicylic acid aspirin pleiotropic phytohormone willow bark orchestrates immune reprogrammingserving salicylic acid willow barksalicylic acid sa provided PLANTS
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Beyond bark thickness:multifunctional explanations for variations in relative bark allocation in temperate forest trees
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作者 Huabin Zhao Zhecheng Liu +5 位作者 Yichen Duan Yongjie Han Luna Zhang Xue Sun Chuankuan Wang Xingchang Wang 《Journal of Forestry Research》 2025年第6期175-186,共12页
While the fire protection function of tree bark has been extensively documented,other critical functions,including storage and mechanical support,have received less attention.In this study we examined:(1)the allometry... While the fire protection function of tree bark has been extensively documented,other critical functions,including storage and mechanical support,have received less attention.In this study we examined:(1)the allometry of bark thickness(and biomass)against wood radius(and biomass)at a disc level,(2)differences in bark allocation between the ratio and the regression approaches,(3)differences between bark thickness and biomass as metrics of bark allocation,and(4)how bark allocation is associated with the evolution of wood from non-porous to diffuse-porous and ring-porous types.Thickness and biomass of bark and wood were measured using trunk discs of 88 individual trees of 36 species in a temperate forest characterized by a long fire interval.Allometric relationships of bark thickness(and biomass)against wood radius(and biomass)explained why both relative bark thickness and biomass decreased with increasing stem diameter.Variations in both among species varied by factors of 3.5 to 7.5 depending on the measurement methods.The ratio approach produced higher estimates of both relative bark thickness and biomass compared to the regression approach,while relative bark thickness was significantly lower than relative bark biomass.Ring-porous species exhibited higher bark thickness based on the ratio approach,which might reflect evolutionary adaptations where ring-porous species have developed thicker bark as protection:thermal insulation against freeze-thaw embolism coupled with carbohydrate reservoirs for hydraulic repair.The regression slope of bark allocation against wood density increased along the wood porosity gradient,demonstrating evolutionary biomechanical coordination between bark and wood.These findings highlight systematic coupling between bark and xylem multifunctionality. 展开更多
关键词 Bark thickness Stem diameter Relative bark thickness Relative bark biomass Bark allocation
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“Lightning survivors” in the forest
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作者 高云 《疯狂英语(新读写)》 2025年第8期52-53,78,79,共4页
Activity 1 Think about the following questions and write down your answers before reading the text.1.What are some common factors that usually cause damage to trees when they are struck by lightning?2.How might the un... Activity 1 Think about the following questions and write down your answers before reading the text.1.What are some common factors that usually cause damage to trees when they are struck by lightning?2.How might the unique characteristics of a tree contribute to its ability to survive a lightning strike? 展开更多
关键词 LIGHTNING bark thickness root system think following questions trees SURVIVAL FOREST moisture content
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Exploring the therapeutic potential of Morus alba Linne extract in targeting localized adiposity
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作者 CHOI You Yeon JIN Seong chul +4 位作者 KIM Mi Hye BAEK Hee Kyung KIM Dong Hyun OH Sung Hyuk YANG Woong Mo 《Journal of Traditional Chinese Medicine》 2025年第5期970-978,共9页
OBJECTIVE:To determine direct targeting of localized adiposity through Morus alba Linne bark injection based on pharmacology network analysis.METHODS:Male C57BL/6J mice were fed a high-fat diet(HFD)to induce obesity.A... OBJECTIVE:To determine direct targeting of localized adiposity through Morus alba Linne bark injection based on pharmacology network analysis.METHODS:Male C57BL/6J mice were fed a high-fat diet(HFD)to induce obesity.After 6 weeks on HFD,the water extract of Morus alba L.bark(MAB,2 mg/mL)was locally injected into one inguinal fat pad,while saline was injected into the other side,3 times/week for 6 weeks(n=6/group).The water extract of MAB was freeze-dried and then diluted in saline before use.RESULTS:HFD-fed mice treated with local MAB topical injection showed reduced adipocyte weight and size in inguinal fat pads by dual-energy X-ray absorptiometry.No toxicity changes seen in liver,spleen,kidney tissue,or alanine aminotransferase/aspartate aminotransferase levels in serum by MAB injection.Protein levels of phosphorylated insulin receptor substrate-1 and glucose transporter type 4,and mRNA expression of adiponectin,were increased in inguinal adipose tissue injected with MAB locally.Locally MAB injection led to a decrease in glucose-6-phosphatase and phosphoenolpyruvate carboxykinase,linked to gluconeogenesis,while forkhead box protein O1,which regulates these factors,was increased.Moreover,there was an increase in adenosine 5‘-monophosphate-activated protein kinase,related to lipogenesis,as well as elevated levels of hormone-sensitive lipase and fatty acid synthase,both associated with lipolysis.These results support the'insulin signaling pathway'and'regulation of lipolysis in adipocytes'identified in the Kyoto Encyclopedia of Genes and Genomes pathway through network analysis.CONCLUSION:This study suggests that MAB topical injection exhibits localized fat reduction by inhibiting insulin resistance,gluconeogenesis and lipogenesis mediator,while activating lipolysis enzymes within targeted adipose site. 展开更多
关键词 Morus Alba Linne Bark localized fat ADIPOSITY OBESITY network pharmacology
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Evaluating the Potential of Birch Bark Suberinic Acids for Solid Wood Impregnation
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作者 Daniela Godina Guntis Sosins +3 位作者 Aigars Paze Janis Rizikovs Raimonds Makars Andreas Treu 《Journal of Renewable Materials》 2025年第1期147-161,共15页
Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberini... Instead of the traditional linear model of taking,making,and disposing,the circular bio-economy promotes a regenerative approach.Although there is potential to create valuable products like betulin,lupeol,and suberinic acids(SA)from outer birch bark,many industries,such as plywood and pulp,often choose to incinerate substan-tial amounts of leftover birch bark to meet their energy needs.This highlights the importance of obtaining valu-able products from wood.The objective of this study was to examine various fractions of SA and assess their potential for wood impregnation.The fractions included SA potassium salts in ethanol(SAK-EtOH)and water(SAK-H2O),SA suspension in water(SAS-H2O)and dried SA,which was subsequently diluted in ethanol(DSA-EtOH).There is significant potential for utilizing SA in wood treatment formulations as a sustainable alternative to harmful petroleum-derived chemicals.This approach not only addresses environmental concerns but also enhances the functionality of wood in construction applications,such as improving impregnation for moisture and fungal protection.Among the solutions tested,the ethanol solution of SA,specifically DSA-EtOH,showed the highest weight percent gain(WPG)and the greatest leaching resistance.GPC analysis showed that SA salts in ethanol(SAK-EtOH)and water(SAK-H2O)predominantly consist of low molecular fractions and each process(acidification and drying)reduces the low molecular content in the sample.This suggests that SA polymerizes after drying,making it necessary to dissolve it in ethanol to meet the requirements for impregnation.Further opti-mization,including adjustments in the concentration of the SA ethanol solution and the curing temperature,is essential to identify the optimal conditions for more in-depth impregnation studies. 展开更多
关键词 Birch bark suberinic acids solid wood impregnation
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Selective procedure for the instant identification of cellular apoptosis induced by natural products
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作者 Ying-Yu Cui 《World Journal of Methodology》 2025年第3期108-113,共6页
BACKGROUND Recently,the identification of cell apoptosis induced by natural products has become research hotspot and frontier in the biopharmaceutical and food industries under the umbrella of global green development... BACKGROUND Recently,the identification of cell apoptosis induced by natural products has become research hotspot and frontier in the biopharmaceutical and food industries under the umbrella of global green development worldwide.Traditionally,cell apoptosis is identified using morphological,biochemical,and cell cycle experiments,which is time consuming,and experimental materials are not from the same group,and it is very hard to ensure the identity and veracity of results of former and latter experiments.AIM To establish a selective,instant,and practical protocol to identify cell apoptosis induced by natural products.METHODS A one transient cell processing procedure(OTCPP)was used to detect human colorectal cancer LoVo cell apoptosis after treatment with Pinus massoniana bark extract(PMBE)at the morphological,biochemical,and cell cycle levels.The methods used included treatment with DNA gel electrophoresis,fluorescence microscopy,and flow cytometry.RESULTS In PMBE-treated LoVo cells,we observed a DNA ladder on gel electrophoresis and fluorescence microscopy revealed"nuclear shrinkage,chromatin condensation or fragmentation".In addition,flow cytometry showed an"obvious apoptosis curve".Thus OTCPP achieved synchronous detection of the morphology,biochemistry,cell cycle,and the DNA content of the cells.CONCLUSION OTCPP can quickly identify apoptosis and measure the apoptosis rate,thereby unifying qualitative and quantitative analysis. 展开更多
关键词 Apoptosis identification Fluorescence microscopy DNA gel electrophoresis Flow cytometry Pinus massoniana bark extract One transient cell processing procedure
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基于听觉掩蔽效应和Bark子波变换的语音增强 被引量:39
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作者 陶智 赵鹤鸣 龚呈卉 《声学学报》 EI CSCD 北大核心 2005年第4期367-372,共6页
提出了一种适用于低信噪比下的提高语音的听觉效果的语音增强方法。该方法在谱减法的基础上有两个特点:首先减参数是根据人耳听觉掩蔽效应提出的且是自适应的;其次采用了与人耳听觉系统特性更为适应的Bark子波变换方法对增强前后的语音... 提出了一种适用于低信噪比下的提高语音的听觉效果的语音增强方法。该方法在谱减法的基础上有两个特点:首先减参数是根据人耳听觉掩蔽效应提出的且是自适应的;其次采用了与人耳听觉系统特性更为适应的Bark子波变换方法对增强前后的语音进行分析。对该算法进行了客观和主观测试,结果表明:与谱减法相比对低信噪比的语音信号,(1)能更好地抑制残留噪声和背景噪声,(2)增强后的语音具有更好的清晰度和可懂度。 展开更多
关键词 听觉掩蔽效应 Bark子波变换 语音增强 宽带噪声 谱减法
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一种新阈值函数的小波包语音增强算法 被引量:15
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作者 任永梅 张雪英 贾海蓉 《计算机应用研究》 CSCD 北大核心 2013年第1期114-116,137,共4页
针对传统软、硬阈值函数去噪方法增强的语音存在失真的问题,提出一种新阈值函数的小波包语音增强算法,同时给出了新阈值函数和新的Bark尺度小波包分解结构。新阈值函数在小波包系数绝对值大于给定阈值的区间内,灵活地结合了软、硬阈值函... 针对传统软、硬阈值函数去噪方法增强的语音存在失真的问题,提出一种新阈值函数的小波包语音增强算法,同时给出了新阈值函数和新的Bark尺度小波包分解结构。新阈值函数在小波包系数绝对值大于给定阈值的区间内,灵活地结合了软、硬阈值函数;在小波包系数绝对值小于给定阈值的区间内,用一种非线性函数代替传统阈值函数中的简单置零,实现了阈值函数的平缓过渡;新的60个频带Bark尺度小波包分解结构能更好地模拟人耳的听觉感知特性。仿真实验结果表明,在高斯白噪声和有色噪声背景下,与传统软、硬阈值函数去噪方法相比,新算法有效提高了增强语音信噪比和分段信噪比,减少了语音失真,具有更好的去噪效果。 展开更多
关键词 语音增强 小波包 阈值函数 Bark尺度小波包分解结构 信噪比 分段信噪比
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一种基于Bark域能量分布的噪声分类方法 被引量:5
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作者 袁文浩 林家骏 +1 位作者 陈宁 王雨 《华东理工大学学报(自然科学版)》 CAS CSCD 北大核心 2013年第4期472-476,共5页
对不同种类噪声的分类处理,可以提高噪声环境下语音信号处理的性能。为了能够准确地区分各类噪声,提出了一种基于Bark域噪声能量分布特性的噪声分类方法。通过将噪声能量从均匀时频空间映射到Bark空间,构造了一个能够有效区分各种噪声... 对不同种类噪声的分类处理,可以提高噪声环境下语音信号处理的性能。为了能够准确地区分各类噪声,提出了一种基于Bark域噪声能量分布特性的噪声分类方法。通过将噪声能量从均匀时频空间映射到Bark空间,构造了一个能够有效区分各种噪声的22维特征向量,并使用支持向量机(SVM)进行模型训练和噪声分类。实验结果表明:所提出的噪声分类方法具有非常高的分类准确率,对用于实验的两种噪声数据集的平均分类准确率分别为99.50%和93.44%。 展开更多
关键词 噪声分类 支持向量机 Bark域 能量分布特性
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基于Bark域噪声估计及掩蔽效应的语音增强 被引量:6
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作者 赵欢 熊敏 侯卫国 《计算机工程》 CAS CSCD 北大核心 2009年第12期261-263,共3页
针对非平稳环境下噪声估计和语音增强性能降低的特点,提出一种基于Bark域的快速自适应噪声谱估计算法。它基于听觉模型,将带噪信号变换到Bark域,并在Bark域内实现基于人耳掩蔽的语音增强。仿真实验表明该算法能充分利用Bark带内频带间... 针对非平稳环境下噪声估计和语音增强性能降低的特点,提出一种基于Bark域的快速自适应噪声谱估计算法。它基于听觉模型,将带噪信号变换到Bark域,并在Bark域内实现基于人耳掩蔽的语音增强。仿真实验表明该算法能充分利用Bark带内频带间的相关性,跟踪快变的背景噪声,提高语音增强性能,减少运算量和复杂度。 展开更多
关键词 语音增强 噪声估计 Bark域 掩蔽效应
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结点阈值小波包变换语音增强新算法 被引量:14
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作者 王娜 郑德忠 《仪器仪表学报》 EI CAS CSCD 北大核心 2007年第5期952-955,共4页
人耳频率分辨率是非线性的,而小波包算法有灵活的时频分析能力,可较好的模拟人耳基底膜的频率分析特性。本文提出了一种新的基于结点阈值的小波包变换语音增强算法。采用Bark尺度小波包对含噪语音进行分解,在语音信号的子带层次上进行... 人耳频率分辨率是非线性的,而小波包算法有灵活的时频分析能力,可较好的模拟人耳基底膜的频率分析特性。本文提出了一种新的基于结点阈值的小波包变换语音增强算法。采用Bark尺度小波包对含噪语音进行分解,在语音信号的子带层次上进行阈值操作,并采用软阈值方法进行阈值处理。采用谱熵法估计结点噪声。实验表明,该算法在多种噪声,尤其是有色噪声和非平稳噪声条件下均有较好的语音增强效果。 展开更多
关键词 语音增强 Bark尺度小波包分解 结点阈值 谱熵法
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基于Fisher比的Bark小波包变换的语音特征提取算法 被引量:6
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作者 王晓华 屈雷 +1 位作者 张超 蒋细伟 《西安工程大学学报》 CAS 2016年第4期452-457,共6页
为解决MFCC特征参数在噪声环境中识别率低的问题,提出一种基于Fisher比的Bark小波包变换特征提取算法.首先采用小波包变换构造Bark滤波器代替三角形的Mel滤波器.其次采用Fisher对Bark滤波后的特征参数进行选择,去除大量干扰信息,节省特... 为解决MFCC特征参数在噪声环境中识别率低的问题,提出一种基于Fisher比的Bark小波包变换特征提取算法.首先采用小波包变换构造Bark滤波器代替三角形的Mel滤波器.其次采用Fisher对Bark滤波后的特征参数进行选择,去除大量干扰信息,节省特征匹配的时间.仿真实验表明,该算法明显提高系统的识别率和鲁棒性. 展开更多
关键词 FISHER BARK 小波包变换 MFCC 说话人识别
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基于BARK子波变换的语音增强方法研究 被引量:2
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作者 李野 吴亚锋 刘雪飞 《计算机工程与应用》 CSCD 北大核心 2009年第33期128-131,共4页
在Bark子波的构造的基础上,提出一种改进的Bark子波变换构造方法,即直接由临界带中心频率确定Bark子波的中心频率,保证了其通带和临界带的对应一致性,并与人耳的听觉系统十分吻合。采用Bark子波对带噪语音进行分解,在语音信号的子带层... 在Bark子波的构造的基础上,提出一种改进的Bark子波变换构造方法,即直接由临界带中心频率确定Bark子波的中心频率,保证了其通带和临界带的对应一致性,并与人耳的听觉系统十分吻合。采用Bark子波对带噪语音进行分解,在语音信号的子带层次上用一种类似于软阈值的无穷阶可导的函数进行阈值处理,并应用谱减法进行二次增强。仿真实验表明,构建Bark子波与增强算法使信噪比和PESQ得分都有较大提高,特别是在信噪比较高时,语音具有很好的清晰度和可懂度。 展开更多
关键词 Bark子波 语音增强 阈值
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时频结合自适应阈值小波包消噪算法 被引量:2
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作者 田玉静 董玉民 左红伟 《应用声学》 CSCD 北大核心 2010年第4期256-262,共7页
在充分考虑人耳听觉特性和噪声统计特性的基础上,提出一种时频结合Bark尺度自适应阈值的语音消噪算法,在Bark频域上自适应调整增强系数可以较准确地进行阈值判定。仿真实验验证,时频结合算法在低信噪比输入情况下较传统语音降噪方法具... 在充分考虑人耳听觉特性和噪声统计特性的基础上,提出一种时频结合Bark尺度自适应阈值的语音消噪算法,在Bark频域上自适应调整增强系数可以较准确地进行阈值判定。仿真实验验证,时频结合算法在低信噪比输入情况下较传统语音降噪方法具有明显优势,其在消除高斯白噪声的同时有效降低了语音损失,可获得最大信噪比,谱失真测度最小,增强语音的MOS(Mean Opinion Score)评分明显提高,具有较好的听觉效果。 展开更多
关键词 小波包消噪 自适应阈值算法 时频结合 Bark尺度
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采用多特征组合优化的语音特征参数研究 被引量:4
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作者 张晓俊 陶智 +2 位作者 吴迪 肖仲喆 赵鹤鸣 《通信技术》 2012年第12期98-100,103,共4页
在研究传统语音特征参数线性预测倒谱系数(LPCC)和梅尔频率倒谱系数(MFCC)的基础上,加入基于人耳听觉特性的Bark子波滤波器组所提取的特征参数,来共同组成特征集。同时将基于遗传算法的相关性特征算法将特征集进行优化,分别采用贝叶斯... 在研究传统语音特征参数线性预测倒谱系数(LPCC)和梅尔频率倒谱系数(MFCC)的基础上,加入基于人耳听觉特性的Bark子波滤波器组所提取的特征参数,来共同组成特征集。同时将基于遗传算法的相关性特征算法将特征集进行优化,分别采用贝叶斯和径向基神经网络算法进行语音识别。实验结果表明本方法与传统的LPCC和MFCC方法相比,平均识别率分别提高了4.66%和3.5%,最佳达到98.1%的识别率。 展开更多
关键词 Bark子波 特征提取 特征优化 语音识别
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