期刊文献+
共找到34,667篇文章
< 1 2 250 >
每页显示 20 50 100
Implied volatility estimation of bitcoin options and the stylized facts of option pricing
1
作者 Noshaba Zulfiqar Saqib Gulzar 《Financial Innovation》 2021年第1期1508-1537,共30页
The recently developed Bitcoin futures and options contracts in cryptocurrency derivatives exchanges mark the beginning of a new era in Bitcoin price risk hedging.The need for these tools dates back to the market cras... The recently developed Bitcoin futures and options contracts in cryptocurrency derivatives exchanges mark the beginning of a new era in Bitcoin price risk hedging.The need for these tools dates back to the market crash of 1987,when investors needed better ways to protect their portfolios through option insurance.These tools provide greater flexibility to trade and hedge volatile swings in Bitcoin prices effectively.The violation of constant volatility and the log-normality assumption of the Black–Scholes option pricing model led to the discovery of the volatility smile,smirk,or skew in options markets.These stylized facts;that is,the volatility smile and implied volatilities implied by the option prices,are well documented in the option literature for almost all financial markets.These are expected to be true for Bitcoin options as well.The data sets for the study are based on short-dated Bitcoin options(14-day maturity)of two time periods traded on Deribit Bitcoin Futures and Options Exchange,a Netherlandsbased cryptocurrency derivative exchange.The estimated results are compared with benchmark Black–Scholes implied volatility values for accuracy and efficiency analysis.This study has two aims:(1)to provide insights into the volatility smile in Bitcoin options and(2)to estimate the implied volatility of Bitcoin options through numerical approximation techniques,specifically the Newton Raphson and Bisection methods.The experimental results show that Bitcoin options belong to the commodity class of assets based on the presence of a volatility forward skew in Bitcoin option data.Moreover,the Newton Raphson and Bisection methods are effective in estimating the implied volatility of Bitcoin options.However,the Newton Raphson forecasting technique converges faster than does the Bisection method. 展开更多
关键词 Bitcoin options Deribit Bitcoin smile implied volatility estimation Numerical estimation
在线阅读 下载PDF
Recover Implied Volatility in Short-term Interest Rate Model
2
作者 ZHA O Fang-fang XU Zuo-liang 《Chinese Quarterly Journal of Mathematics》 2017年第4期395-406,共12页
This paper concerns an inverse problem of recovering implied volatility in short-term interest rate model from the market prices of zero-coupon bonds. Based on lineariza-tion, an analytic solution, which is given as a... This paper concerns an inverse problem of recovering implied volatility in short-term interest rate model from the market prices of zero-coupon bonds. Based on lineariza-tion, an analytic solution, which is given as a power series, is derived for the direct problem.By neglecting high order terms in the power series, an integral equation about the pertur-bation of volatility is formulated and the Tikhonov regularization method is applied to solvethe integral equation. Finally numerical experiments are given and the results show that the method is effective. 展开更多
关键词 implied volatility INVERSE PROBLEM LINEARIZATION
在线阅读 下载PDF
Deterministic modelling of implied volatility in cryptocurrency options with underlying multiple resolution momentum indicator and non-linear machine learning regression algorithm
3
作者 F.Leung M.Law S.K.Djeng 《Financial Innovation》 2024年第1期499-523,共25页
Modeling implied volatility(IV)is important for option pricing,hedging,and risk management.Previous studies of deterministic implied volatility functions(DIVFs)propose two parameters,moneyness and time to maturity,to ... Modeling implied volatility(IV)is important for option pricing,hedging,and risk management.Previous studies of deterministic implied volatility functions(DIVFs)propose two parameters,moneyness and time to maturity,to estimate implied volatility.Recent DIVF models have included factors such as a moving average ratio and relative bid-ask spread but fail to enhance modeling accuracy.The current study offers a generalized DIVF model by including a momentum indicator for the underlying asset using a relative strength index(RSI)covering multiple time resolutions as a factor,as momentum is often used by investors and speculators in their trading decisions,and in contrast to volatility,RSI can distinguish between bull and bear markets.To the best of our knowledge,prior studies have not included RSI as a predictive factor in modeling IV.Instead of using a simple linear regression as in previous studies,we use a machine learning regression algorithm,namely random forest,to model a nonlinear IV.Previous studies apply DVIF modeling to options on traditional financial assets,such as stock and foreign exchange markets.Here,we study options on the largest cryptocurrency,Bitcoin,which poses greater modeling challenges due to its extreme volatility and the fact that it is not as well studied as traditional financial assets.Recent Bitcoin option chain data were collected from a leading cryptocurrency option exchange over a four-month period for model development and validation.Our dataset includes short-maturity options with expiry in less than six days,as well as a full range of moneyness,both of which are often excluded in existing studies as prices for options with these characteristics are often highly volatile and pose challenges to model building.Our in-sample and out-sample results indicate that including our proposed momentum indicator significantly enhances the model’s accuracy in pricing options.The nonlinear machine learning random forest algorithm also performed better than a simple linear regression.Compared to prevailing option pricing models that employ stochastic variables,our DIVF model does not include stochastic factors but exhibits reasonably good performance.It is also easy to compute due to the availability of real-time RSIs.Our findings indicate our enhanced DIVF model offers significant improvements and may be an excellent alternative to existing option pricing models that are primarily stochastic in nature. 展开更多
关键词 implied volatility Cryptocurrency options Momentum indicator Relative strength index Machine learning Random Forest regression Black-Scholes-Merton equation
在线阅读 下载PDF
A Hybrid Particle Swarm Optimization to Forecast Implied Volatility Risk
4
作者 Kais Tissaoui Sahbi Boubaker +2 位作者 Waleed Saud Alghassab Taha Zaghdoudi Jamel Azibi 《Computers, Materials & Continua》 SCIE EI 2022年第11期4291-4309,共19页
The application of optimization methods to prediction issues is a continually exploring field.In line with this,this paper investigates the connectedness between the infected cases of COVID-19 and US fear index from a... The application of optimization methods to prediction issues is a continually exploring field.In line with this,this paper investigates the connectedness between the infected cases of COVID-19 and US fear index from a forecasting perspective.The complex characteristics of implied volatility risk index such as non-linearity structure,time-varying and nonstationarity motivate us to apply a nonlinear polynomial Hammerstein model with known structure and unknown parameters.We use the Hybrid Particle Swarm Optimization(HPSO)tool to identify the model parameters of nonlinear polynomial Hammerstein model.Findings indicate that,following a nonlinear polynomial behaviour cascaded to an autoregressive with exogenous input(ARX)behaviour,the fear index in US financial market is significantly affected by COVID-19-infected cases in the US,COVID-19-infected cases in the world and COVID-19-infected cases in China,respectively.Statistical performance indicators provided by the developed models show that COVID-19-infected cases in the US are particularly powerful in predicting the Cboe volatility index compared to COVID-19-infected cases in the world and China(MAPE(2.1013%);R2(91.78%)and RMSE(0.6363 percentage points)).The proposed approaches have also shown good convergence characteristics and accurate fits of the data. 展开更多
关键词 Forecasting Cboe’s volatility index COVID-19 pandemic nonlinear polynomial hammerstein model hybrid particle swarm optimization
在线阅读 下载PDF
Coin impact on cross‑crypto realized volatility and dynamic cryptocurrency volatility connectedness
5
作者 Burak Korkusuz Mehmet Sahiner 《Financial Innovation》 2025年第1期3732-3763,共32页
This study evaluates the predictive accuracy of traditional time series(TS)models versus machine learning(ML)methods in forecasting realized volatility across major cryptocurrencies—Bitcoin(BTC),Ethereum(ETH),Litecoi... This study evaluates the predictive accuracy of traditional time series(TS)models versus machine learning(ML)methods in forecasting realized volatility across major cryptocurrencies—Bitcoin(BTC),Ethereum(ETH),Litecoin(LTC),and Ripple(XRP).Employing high-frequency data,we analyze cross-cryptocurrency volatility dynamics through two complementary approaches:volatility forecasting and connectedness analysis.Our findings reveal three key insights:(i)TS models,particularly the heterogeneous autoregressive(HAR)model,exhibit superior predictive performance over their ML counterparts,with the long short-term memory(LSTM)model providing competitive yet inconsistent results due to overfitting and short-term volatility challenges;(ii)including lagged realized volatility of large-cap coins improves predictive accuracy for mid-cap coins,especially XRP,whereas forecasts for largecap coins remain stable,indicating more resilient volatility patterns;and(iii)volatility connectedness analysis reveals substantial spillover effects,particularly pronounced during market turmoil,with large-cap assets(BTC and ETH)acting as primary volatility transmitters and mid-cap assets(XRP and LTC)serving as volatility receivers.These results contribute to the understanding of volatility forecasting and risk management in cryptocurrency markets,offering implications for investors and policymakers in managing market risk and interdependencies in digital asset portfolios. 展开更多
关键词 volatility forecasting Realized volatility Bitcoin Cross-cryptocurrency impact Dynamic connectedness Machine learning Network analysis Econometric models
在线阅读 下载PDF
Pricing Multi-Strike Quanto Call Options on Multiple Assets with Stochastic Volatility, Correlation, and Exchange Rates
6
作者 Boris Ter-Avanesov Gunter Meissner 《Applied Mathematics》 2025年第1期113-142,共30页
Quanto options allow the buyer to exchange the foreign currency payoff into the domestic currency at a fixed exchange rate. We investigate quanto options with multiple underlying assets valued in different foreign cur... Quanto options allow the buyer to exchange the foreign currency payoff into the domestic currency at a fixed exchange rate. We investigate quanto options with multiple underlying assets valued in different foreign currencies each with a different strike price in the payoff function. We carry out a comparative performance analysis of different stochastic volatility (SV), stochastic correlation (SC), and stochastic exchange rate (SER) models to determine the best combination of these models for Monte Carlo (MC) simulation pricing. In addition, we test the performance of all model variants with constant correlation as a benchmark. We find that a combination of GARCH-Jump SV, Weibull SC, and Ornstein Uhlenbeck (OU) SER performs best. In addition, we analyze different discretization schemes and their results. In our simulations, the Milstein scheme yields the best balance between execution times and lower standard deviations of price estimates. Furthermore, we find that incorporating mean reversion into stochastic correlation and stochastic FX rate modeling is beneficial for MC simulation pricing. We improve the accuracy of our simulations by implementing antithetic variates variance reduction. Finally, we derive the correlation risk parameters Cora and Gora in our framework so that correlation hedging of quanto options can be performed. 展开更多
关键词 Quanto Option Multi-Strike Option Stochastic volatility (SV) Stochastic Correlation (SC) Stochastic Exchange Rates (SER) CORA GORA Correlation Risk
在线阅读 下载PDF
Bitcoin’s Weekend Effect: Returns, Volatility, and Volume (2014-2024)
7
作者 Zhe Xu 《Proceedings of Business and Economic Studies》 2025年第5期54-61,共8页
Using daily BTC-USD data from September 19,2014 to January 21,2024,this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins:average returns,close-to-close volatility,and trading act... Using daily BTC-USD data from September 19,2014 to January 21,2024,this paper re-examines whether weekends differ from weekdays for Bitcoin along three margins:average returns,close-to-close volatility,and trading activity.We implement Welch mean comparisons and HAC-robust OLS with month fixed effects(bandwidths 5,7,and 14).In the full sample and across subsamples(2016–2019;2020–2023;early 2024),we find no detectable weekend–weekday gap in average returns,while volatility and trading activity are lower on weekends.The patterns are robust to using squared returns as a volatility proxy.The joint evidence is consistent with liquidity and attention mechanisms—quieter weekends rather than compensating return premia.Replication files reproduce all tables and figures. 展开更多
关键词 Bitcoin Weekend effect Day-of-the-week volatility Trading volume HAC Cryptocurrency
在线阅读 下载PDF
Cryptocurrency Volatility and Its Impact on Emerging Markets: Quantitative Analysis
8
作者 Xinyang Kray Wang 《Economics World》 2025年第2期106-112,共7页
Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,... Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,we empirically analyse the volatility risk of cryptocurrencies through quantitative analysis models,comprehensively using the Markov state transition GARCH model with skewed distribution(Skew-MSGARCH)and the autoregressive conditional volatility density ARJI model introducing the Poisson jump factor,and selecting the earliest developed and the most mature currency price volatility daily return series,to deeply explore the volatility risk of digital cryptocurrencies.risk.Finally,it can be seen through in-depth analyses that the expectation factor and information inducement are the main reasons leading to the exacerbation of the volatility risk of digital cryptocurrencies.It is recommended that this situation be optimised and improved in terms of the value function of digital cryptocurrencies themselves and the implementation of systematic risk management and regulatory innovation.As an important component of the digital economy,blockchain technology can effectively regulate and improve the volatility of digital cryptocurrencies under macroeconomic policies,thereby maintaining the security and stability of emerging financial markets. 展开更多
关键词 cryptocurrency volatility emerging markets quantitative analysis
在线阅读 下载PDF
Forecasting cryptocurrency volatility:a novel framework based on the evolving multiscale graph neural network
9
作者 Yang Zhou Chi Xie +2 位作者 Gang‑Jin Wang Jue Gong You Zhu 《Financial Innovation》 2025年第1期2484-2535,共52页
Cryptocurrency is a remarkable financial innovation that has affected the financial system in fundamental ways.Its increasingly complex interactions with the conventional financial market make precisely forecasting it... Cryptocurrency is a remarkable financial innovation that has affected the financial system in fundamental ways.Its increasingly complex interactions with the conventional financial market make precisely forecasting its volatility increasingly challenging.To this end,we propose a novel framework based on the evolving multiscale graph neural network(EMGNN).Specifically,we embed a graph that depicts the interactions between the cryptocurrency and conventional financial markets into the predictive process.Furthermore,we employ hierarchical evolving graph structure learners to model the dynamic and scale-specific interactions.We also evaluate our framework’s robustness and discuss its interpretability by extracting the learned graph structure.The empirical results show that(i)cryptocurrency volatility is not isolated from the conventional market,and the embedded graph can provide effective information for prediction;(ii)the EMGNN-based forecasting framework generally yields outstanding and robust performance in terms of multiple volatility estimators,cryptocurrency samples,forecasting horizons,and evaluation criteria;and(iii)the graph structure in the predictive process varies over time and scales and is well captured by our framework.Overall,our work provides new insights into risk management for market participants and into policy formulation for authorities. 展开更多
关键词 Cryptocurrency volatility forecasting Graph neural network Deep learning Multiscale
在线阅读 下载PDF
Discounted‑likelihood valuation of variance and volatility swaps
10
作者 Napat Rujeerapaiboon Sanae Rujivan Hongdan Chen 《Financial Innovation》 2025年第1期536-569,共34页
The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses... The valuation of financial derivatives often assumes risk neutrality with respect to the risk-neutral martingale measure,which prevents arbitrage opportunities.However,casual traders may still incur substantial losses when trading at this risk-neutral price,especially when the price has to be paid now and the payoff is only realized in the future.This study proposes a new valuation framework that provides risksensitive investors with an additional safeguard.The proposed framework embraces a worst-case perspective while exploiting the underlier’s stochastic process,representing a combination of robust optimization and stochastic programming.Notably,it aims to mitigate losses in the likelier scenarios of the underlying asset’s prices.When the underlier’s returns are independent and lognormally but not necessarily identically distributed,our approach for pricing variance and volatility swaps could be greatly simplified,benefit from parallel computing,and be solved by a two-dimensional grid search.We further derive a closed-form solution in some special stationary cases and provide experimental results to highlight the effect of risk aversion on fending off sizable trading losses. 展开更多
关键词 Variance swaps volatility swaps Derivative pricing Robust optimization Risk aversion
在线阅读 下载PDF
Power Options Pricing under Markov Regime-Switching Two-Factor Stochastic Volatility Jump-Diffusion Model
11
作者 HAN Shu-shu WEI Yu-ming 《Chinese Quarterly Journal of Mathematics》 2025年第1期59-73,共15页
In this paper,we incorporate Markov regime-switching into a two-factor stochastic volatility jump-diffusion model to enhance the pricing of power options.Furthermore,we assume that the interest rates and the jump inte... In this paper,we incorporate Markov regime-switching into a two-factor stochastic volatility jump-diffusion model to enhance the pricing of power options.Furthermore,we assume that the interest rates and the jump intensities of the assets are stochastic.Under the proposed framework,first,we derive the analytical pricing formula for power options by using Fourier transform technique,Esscher transform and characteristic function.Then we provide the efficient approximation to calculate the analytical pricing formula of power options by using the FFT approach and examine the accuracy of the approximation by Monte Carlo simulation.Finally,we provide some sensitivity analysis of the model parameters to power options.Numerical examples show this model is suitable for empirical work in practice. 展开更多
关键词 Power options Markov regime-switching Stochastic volatility Stochastic interest rate Stochastic intensity
在线阅读 下载PDF
Price volatility spreaders in China's coal market in the carbon neutrality context:an evolution analysis based on a transfer entropy network and rank aggregation
12
作者 Chan Liu Han Hu +4 位作者 Zhigang Wang Feng An Xueyong Liu Ze Wang Zhanglu Tan 《International Journal of Coal Science & Technology》 2025年第2期145-157,共13页
This paper investigates China's coal price volatility spreaders(CPVSs)from the supply side to locate the volatility source since coal price volatility may destabilize many downstream products'prices or even br... This paper investigates China's coal price volatility spreaders(CPVSs)from the supply side to locate the volatility source since coal price volatility may destabilize many downstream products'prices or even bring uncertainties to macroeconomic output.Especially in the carbon neutrality context,China's coal market is being reconstructed and responding to imbalances between supply and demand;identifying the CPVSs helps alleviate rising market instability and prevent energy-induced system risk.To achieve this objective,we explore causalities among 938 weekly coal prices reported by different coal-producing areas of China from 2006.9.4 to 2021.7.12 using the transfer entropy method.Then,coal price volatility influence is quantified to identify the CPVSs by conjointly using complex network theory and a rank aggregation method.The validity test demonstrates that the proposed hybrid method efficiently identifies the CPVSs as it correlates to many price determinants,e.g.,electricity and coal consumption and generation.The empirical results show that causalities among coal prices changed dramatically in 2016,2018,and 2020,affected by coal decapacity and carbon neutrality policies.Before 2018,coal-producing provinces with strong demand for coal and electricity,e.g.,Jiangxi,Chongqing,and Sichuan,were CPVSs;after 2019,those with comparative advantages in coal supply,e.g.,Gansu and Ningxia,were CPVSs.Overall,the coal market is unstable and sensitive to energy policy and external shocks.Policymakers and market participants are recommended to monitor and manage the CPVSs to improve energy security,avoid policy-induced instability and prevent risks caused by coal price fluctuations. 展开更多
关键词 Coal price volatility Carbon neutrality Complex network Transfer entropy Aggregate ranking
在线阅读 下载PDF
Baidu News and the return volatility of Chinese commodity futures:evidence for the sequential information arrival hypothesis
13
作者 Ruwei Zhao Xiong Xiong +2 位作者 Junjun Ma Yuzhao Zhang Yongjie Zhang 《Financial Innovation》 2025年第1期2279-2302,共24页
This study uses Baidu News data and introduces a novel proxy for the rate of information flow to examine its relationship with return volatility in Chinese commodity futures and to test two competing hypotheses.We exa... This study uses Baidu News data and introduces a novel proxy for the rate of information flow to examine its relationship with return volatility in Chinese commodity futures and to test two competing hypotheses.We examine the contemporaneous relationships using correlation coefficient analysis,and find apparent differences between the information flow-return volatility relationship and the information flowtrading volume relationship.The empirical evidence contradicts the mixture of distribution hypothesis(MDH)and suggests that the rate of information flow distinctly affects trading volume and volatility.We conducted linear and nonlinear Granger causality tests to explore the sequential information arrival hypothesis(SIAH).The empirical results prove that a lead-lag linear and nonlinear causality exists between the information flow and return volatility of commodity futures,which is consistent with SIAH.In other words,a partial equilibrium exists before reaching the ultimate equilibrium when the new information arrives in the market.Finally,these findings are robust to alternative measurement of return volatility and subperiod analysis.Our findings reject the MDH and support the SIAH in the context of Chinese commodity futures. 展开更多
关键词 Baidu News Chinese commodity futures Return volatility Sequential information arrival hypothesis Mixture of distribution hypothesis
在线阅读 下载PDF
Controllingagricultural product price volatility:An empirical analysis fromCameroon
14
作者 Ivette Gnitedem KEUBENG George Achu MULUH Vatis Christian KEMEZANG 《Regional Sustainability》 2025年第2期102-116,共15页
Motivated by a significant impact of price volatility on food security and economic stability inCameroon,this study aims to understand the factors influencing agricultural product price volatility(APPV)and formulateef... Motivated by a significant impact of price volatility on food security and economic stability inCameroon,this study aims to understand the factors influencing agricultural product price volatility(APPV)and formulateeffective policies for mitigating its negative impactand promoting sustainable economic growth.Specifically,this research used theautoregressive distributed lag-error correction model(ARDL-ECM)to analyse the impact of agricultural productivity,agricultural product imports,population,temperature variation,gross domestic product(GDP)per capita,and government expenditure on APPV based on the annual data from 2000 to 2021.The ARDL-ECM estimation results revealed that agricultural productivity(β=4.901),agricultural product imports(β=1.012),population(β=13.635),and GDP per capita(β=2.794)were positively related toAPPV,while temperature variation(β=-0.990)and government expenditure(β=-8.585)were negatively related toAPPVin the long term.However,temperature variation had a positive relationship with APPV in the short term.Moreover,the Granger causality test showed that there werebidirectional causality of APPV with agricultural productivityandagricultural product imports,and unidirectional causality of APPVwith population,temperature variation,GDP per capita,and government expenditure.The findings highlight the importance of public policies in stabilizing agricultural product prices by investing in agricultural research,improving access to agricultural inputs,strengthening farmer capacities,implementing climate adaptation measures,and enhancing rural infrastructure.Thesepolicies can reduce APPV,improve food security,and promote inclusive economic growth in Cameroon. 展开更多
关键词 Agricultural product price volatility(APPV) Autoregressive distributed lag-error correction model(ARDL-ECM) Food security Agricultural productivity Climate change
在线阅读 下载PDF
经济政策不确定性与中国股市波动率——基于已实现SV-MIDAS模型的实证研究
15
作者 吴鑫育 朱志田 马超群 《中国管理科学》 北大核心 2026年第1期28-40,共13页
本文构建了已实现SV-MIDAS(RSV-MIDAS)模型框架,将经济政策不确定性(EPU)引入其中,实证分析了EPU对中国股市波动率的影响以及预测作用。为了估计RSV-MIDAS模型的参数,本文提出基于连续粒子滤波的极大似然估计方法,并利用蒙特卡罗模拟实... 本文构建了已实现SV-MIDAS(RSV-MIDAS)模型框架,将经济政策不确定性(EPU)引入其中,实证分析了EPU对中国股市波动率的影响以及预测作用。为了估计RSV-MIDAS模型的参数,本文提出基于连续粒子滤波的极大似然估计方法,并利用蒙特卡罗模拟实验验证了该估计方法的有效性。采用月度中国EPU指数和日内高频上证综合指数与深证成分指数价格数据,对引入EPU的RSV-MIDAS(RSV-MIDAS-EPU)模型进行实证研究,结果表明:EPU对中国股市长期波动率具有显著的负向影响,即EPU水平提高,预期中国股市长期波动率会下降;EPU对股市长期波动率的影响相比月度已实现波动率(RV)对股市长期波动率的影响持续时间更长。利用多种损失函数和模型置信集(MCS)检验作为判断准则,实证比较了RSV-MIDAS-EPU模型与其他竞争模型对中国股市波动率的样本外预测能力,结果表明:已实现测度和EPU对于中国股市波动率预测具有重要作用;RSV-MIDAS-EPU模型具有更优越的波动率预测能力。最后,通过波动率择时策略分析发现,RSVMIDAS-EPU模型能够获得更高的投资组合经济价值。 展开更多
关键词 经济政策不确定性 波动率预测 已实现SV-MIDAS 连续粒子滤波 波动率择时
原文传递
葡萄牙棒孢酵母J5不同培养物的挥发性代谢产物分析
16
作者 许彬 刘煜祈 +5 位作者 宋锦波 李宜笑 仵花芝 李慧星 张建辉 李刚 《中国食品学报》 北大核心 2026年第1期315-328,共14页
研究葡萄牙棒孢酵母J5不同培养物的挥发性代谢产物。以马铃薯、高粱、小麦和红小米的提取物为培养基质,培养葡萄牙棒孢酵母J5获得4种培养物。采用顶空固相微萃取-全二维气相色谱-四极杆飞行时间质谱测定培养物的挥发性代谢产物,利用化... 研究葡萄牙棒孢酵母J5不同培养物的挥发性代谢产物。以马铃薯、高粱、小麦和红小米的提取物为培养基质,培养葡萄牙棒孢酵母J5获得4种培养物。采用顶空固相微萃取-全二维气相色谱-四极杆飞行时间质谱测定培养物的挥发性代谢产物,利用化学计量学方法分析数据。结果表明:葡萄牙棒孢酵母J5的4种培养物中,共检测到65种挥发性代谢产物。红小米培养物(HXM)中挥发性代谢产物的种类最丰富,小麦培养物(XM)中挥发性代谢产物的总浓度最高。乙醇、己酸乙酯、辛酸乙酯、乙酸苯乙酯、乙醛、庚酸乙酯在3种谷物培养物中含量差异不显著。主成分分析得分图表明,高粱培养物(GL)和XM具有相似性。XM和HXM的正交偏最小二乘判别分析模型获得40种投影中变量重要性(VIP)>1且含量差异显著的关键差异挥发性代谢产物,另外有5种含量差异显著而VIP<1的挥发性代谢产物。HXM中己醇、乙酸丁酯、庚醛、3-甲基丁醛、2-戊基呋喃、1-辛烯-3醇、3-甲基-1-丁醇、顺-2-庚烯醛的相对气味活性值(ROAV)>1,与XM中的重要香气物质虽有所不同,但这些物质是发酵酒中常见的香气成分,具有优良的风味。这说明采用红小米培养葡萄牙棒孢酵母,用于红谷黄酒增香是可行的。 展开更多
关键词 葡萄牙棒孢酵母 培养物 挥发性 代谢产物 香气活性
在线阅读 下载PDF
HS-SPME-GC-MS结合多元统计分析对金银花线香燃烧产物的鉴定
17
作者 张颖 及华 +2 位作者 李梦雪 于文龙 章丽 《中国农业科技导报(中英文)》 北大核心 2026年第1期242-254,共13页
为鉴定线香中主要挥发性成分,进一步揭示这些成分在不同样品间的差异及其对香气特征的贡献,采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)结... 为鉴定线香中主要挥发性成分,进一步揭示这些成分在不同样品间的差异及其对香气特征的贡献,采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)结合多元统计分析方法对粘粉燃烧产物、金银花粉、金银花粉燃烧产物、线香燃烧产物中挥发性成分进行提取鉴定,并确定关键挥发性成分。结果表明,从4种样品中共鉴定出102种挥发性成分,以芳香族、杂环类、酮类化合物等成分为主。主成分分析、正交偏最小二乘法判别分析及聚类热图分析表明,金银花粉燃烧产物和线香燃烧产物挥发性成分组成相似,与粘粉燃烧产物及金银花粉挥发性成分存在较大差异,并筛选出25种投影变量的重要性(variable important for the projection,VIP)>1的关键挥发性成分。研究结果为金银花线香的进一步开发提供理论依据,也为中药材的应用拓展了新方向。 展开更多
关键词 金银花 线香 挥发性成分 多元统计分析
在线阅读 下载PDF
当“儿童”作为镜像:中国现代儿童文学中的自我重塑与叙事建构
18
作者 金莉莉 《河北师范大学学报(哲学社会科学版)》 2026年第2期149-156,共8页
晚清以来,“儿童的发现”重构了现代文学的知识体系,并通过叙事实验催生了作家自我认知的转型。已有研究多关注中国现代儿童文学的观念史或文体特征,却忽视了作家通过“双重叙事身份”(成人/儿童意识的互渗)重塑自我主体性的努力。鲁迅... 晚清以来,“儿童的发现”重构了现代文学的知识体系,并通过叙事实验催生了作家自我认知的转型。已有研究多关注中国现代儿童文学的观念史或文体特征,却忽视了作家通过“双重叙事身份”(成人/儿童意识的互渗)重塑自我主体性的努力。鲁迅、老舍、茅盾等众多作家在儿童小说翻译、创作中对语言及叙事惯性的突破,印证了想象“理想读者(儿童)”与叙事形式的内在关联,以及以“他者化”的儿童镜像来实现自我启蒙,并最终建立和完善“新人”的现代表达。这一新的作者/读者关系深刻体现出现代作家探索中国化叙事形式的不断尝试,也为现代时期“人的觉醒”议题提供了另一种解释路径。 展开更多
关键词 现代儿童文学 叙事 隐含作者 隐含读者 自我重塑
在线阅读 下载PDF
基于GC-MS结合多元统计方法分析野生地黄伴生土壤中挥发性有机物特征
19
作者 刘雪 程梦娟 +5 位作者 王丰青 龚海燕 刘庆普 雷敬卫 张娟 谢彩侠 《中华中医药学刊》 北大核心 2026年第2期201-206,I0036-I0039,共10页
目的对不同产区野生地黄伴生土壤中挥发性有机物(Volatile organic compounds,VOCs)进行分析,为探讨地黄药材不同产区之间差异的成因提供理论依据。方法以道地与非道地产区的35批野生地黄伴生土壤作为研究对象,利用气相色谱-质谱联用(Ga... 目的对不同产区野生地黄伴生土壤中挥发性有机物(Volatile organic compounds,VOCs)进行分析,为探讨地黄药材不同产区之间差异的成因提供理论依据。方法以道地与非道地产区的35批野生地黄伴生土壤作为研究对象,利用气相色谱-质谱联用(Gas chromatography-mass spectrometry,GC-MS)方法分析其二氯甲烷及乙酸乙酯部位中的VOCs,结合SIMCA 14.1、SPSS 24等统计软件对归一化后的数据进行多元统计分析,确定道地与非道地野生地黄伴生土壤VOCs的差异性。结果35批野生地黄伴生土壤中二氯甲烷部位的VOCs主要有酯类、醇类、烷烃类、酚类成分,其中烷烃类、酚类、酯类的相对含量在道地与非道地产区中差异存在统计学意义;乙酸乙酯部位的VOCs主要为酯类、烷烃类、醇类、酚类、酰胺类、烯烃类成分,其中酯类、烷烃类、醇类、酚类、酰胺类、烯烃类的相对含量在道地与非道地产区中差异存在统计学意义;多元统计学分析表明,野生地黄土壤样品均按照道地产区与非道地产区各自聚为一类,烷烃类、酸类、酯类为引起两者特征差异的主要成分。结论道地与非道地野生地黄土壤中所含的VOCs种类相似,但含量特征差异较大,烷烃类、酸类、酯类为主要差异性成分。 展开更多
关键词 野生地黄 伴生土壤 挥发性有机物 气质联用
原文传递
桂枝挥发油对肺炎克雷伯菌的抑菌作用研究
20
作者 徐军 陈人萍 +3 位作者 刘卫 高佳 李会影 张英华 《特产研究》 2026年第1期97-101,111,共6页
本文旨在研究桂枝挥发油对肺炎克雷伯菌的体外、体内抑制作用。采用水蒸气蒸馏法提取桂枝挥发油(VORC),琼脂稀释法测定VORC对肺炎克雷伯菌的最低抑菌浓度(MIC);通过生长曲线法检测VORC对肺炎克雷伯菌生长能力的影响;建立肺炎克雷伯菌诱... 本文旨在研究桂枝挥发油对肺炎克雷伯菌的体外、体内抑制作用。采用水蒸气蒸馏法提取桂枝挥发油(VORC),琼脂稀释法测定VORC对肺炎克雷伯菌的最低抑菌浓度(MIC);通过生长曲线法检测VORC对肺炎克雷伯菌生长能力的影响;建立肺炎克雷伯菌诱导大鼠重症肺炎模型,探讨VORC在体内的抗菌作用。结果表明,VORC对肺炎克雷伯菌的MIC为2.5 mg/m L,在体外能显著抑制肺炎克雷伯菌的生长,且抑菌活性呈浓度依赖性;临床表现证实了建模成功;灌胃给予高(0.12mL/kg)、中(0.06mL/kg)剂量VORC后,能显著降低大鼠LI值(P<0.01),明显改善动脉血气指标(P<0.01)且能显著降低肺内活菌数(P<0.05)。本研究表明VORC对肺炎克雷伯菌有较好的抑菌效果。 展开更多
关键词 桂枝 挥发油 抑菌作用 肺炎克雷伯菌
暂未订购
上一页 1 2 250 下一页 到第
使用帮助 返回顶部