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Diffusion tensor imaging and proton magnetic resonance spectroscopy in brain tumor Correlation between structure and metabolism
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作者 Zhigang Min Chen Niu +2 位作者 Netra Rana Huanmei Ji Ming Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第10期930-937,共8页
Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individ... Proton magnetic resonance spectroscopy and diffusion tensor imaging are non-invasive techniques used to detect metabolites and water diffusion in vivo. Previous studies have confirmed a positive correlation of individual fractional anisotropy values with N-acetylaspartate/creatine and N-acetylaspartate/choline ratios in tumors, edema, and normal white matter. This study divided the brain parenchyma into tumor, pedtumoral edema, and normal-appearing white matter according to MRI data, and analyzed the correlation of metabolites with water molecular diffusion. Results demonstrated that in normal-appearing white matter, N-acetylaspartate/creatine ratios were positively correlated with fractional anisotropy values, negatively correlated with radial diffusivities, and positively correlated with maximum eigenvalues. Maximum eigenvalues and radial diffusivities in peritumoral edema showed a negative correlation with choline, N-acetylaspartate, and creatine. Radial diffusivities in tumor demonstrated a negative correlation with choline. These data suggest that the relationship between metabolism and structure is markedly changed from normal white matter to peritumoral edema and tumor. Neural metabolism in the peritumoral edema area decreased with expanding extracellular space. The normal relationship of neural function and microstructure disappeared in the tumor region. 展开更多
关键词 neural regeneration NEUROIMAGING brain neoplasms magnetic resonance spectroscopy diffusiontensor imaging METABOLISM diffusion anisotropy EDEMA nerve fiber extracellular space correlation analysis grants-supported paper NEUROREGENERATION
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Measurement of Protein 53 Diffusion Coefficient in Live HeLa Cells Using Raster Image Correlation Spectroscopy (RICS)
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作者 Sungmin Hong Ying-Nai Wang +5 位作者 Hirohito Yamaguchi Harinibytaraya Sreenivasappa Chao-Kai Chou Pei-Hsiang Tsou Mien-Chie Hung Jun Kameoka 《Journal of Biomaterials and Nanobiotechnology》 2010年第1期31-36,共6页
We have applied Raster Image Correlation Spectroscopy (RICS) technique to characterize the dynamics of protein 53 (p53) in living cells before and after the treatment with DNA damaging agents. HeLa cells expressing Gr... We have applied Raster Image Correlation Spectroscopy (RICS) technique to characterize the dynamics of protein 53 (p53) in living cells before and after the treatment with DNA damaging agents. HeLa cells expressing Green Fluores-cent Protein (GFP) tagged p53 were incubated with and without DNA damaging agents, cisplatin or eptoposide, which are widely used as chemotherapeutic drugs. Then, the diffusion coefficient of GFP-p53 was determined by RICS and it was significantly reduced after the drug treatment while that of the one without drug treatment was not. It is suggested that the drugs induced the interaction of p53 with either other proteins or DNA. Together, our results demonstrated that RICS is able to detect the protein dynamics which may be associated with protein-protein or protein-DNA interactions in living cells and it may be useful for the drug screening. 展开更多
关键词 RASTER Image correlation Spectroscopy diffusion COEFFICIENT p53 DNA DAMAGE
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Evaluation of the correlation between ammonia nitrogen and p-toluidine using sequencing batch reactor treating synthetic p-toluidine wastewater 被引量:2
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作者 ZHANG Bo CHEN Jin-long WANG Fan ZHANG Wei-ming ZHANG Quan-xing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2006年第2期259-262,共4页
This paper presents lab-scale experiment carried out to evaluate the correlation between ammonia nitrogen (NH3-N) and p-toluidine using sequencing batch reactor treating synthetic p-toluidine wastewater. The profile... This paper presents lab-scale experiment carried out to evaluate the correlation between ammonia nitrogen (NH3-N) and p-toluidine using sequencing batch reactor treating synthetic p-toluidine wastewater. The profiles of NH3-N and p-toluidine were traced under the concentration of sucrose in the influent varied from 0 to 500 mg/L, aerated airflow varied from 0.6 to 1.2 L/min and temperature varied from 10 to 25℃, respectively. The results showed that the concentration of NH3-N turned from increase to decrease when p-toluidine was nearly completely biodegraded, so the profile of NH3-N could clearly indicate the endpoint of p-toluidine biodegradation. And the profile of NH3-N was not influenced by the sucrose in the influent, aerated airflow and temperature. It is showed that using ammonia nitrogen as monitoring and control parameter is feasible and reliable and has promising application in amine wastewater treatment by SBR. 展开更多
关键词 sequencing batch reactor correlation ammonia nitrogen P-TOLUIDINE BIODEGRADATION
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CORRELATION AND PREDICTION OF LIQUID DIFFUSION COEFFICIENTS IN BINARY SYSTEMS 被引量:1
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作者 杨晓宁 王榕树 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1996年第2期13-20,共8页
A theoretical model to correlate and predict the liquid diffusion coefficients in binary sys-tems has been developed.Based on this mode1 the diffusion coefficient of 73 binary systems have beencorrelated,the overall a... A theoretical model to correlate and predict the liquid diffusion coefficients in binary sys-tems has been developed.Based on this mode1 the diffusion coefficient of 73 binary systems have beencorrelated,the overall average deviation of the correlation for diffusion coefficients is 0.009.Forbinary systems the diffusion coefficients have been predicted from vapor liquid phase equilibrium(VLE)and vice versa. 展开更多
关键词 LIQUID diffusion COEFFICIENT correlation PREDICTION
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MagicTalk: Implicit and explicit correlation learning for diffusion-based emotional talking face generation
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作者 Chenxu Zhang Chao Wang +7 位作者 Jianfeng Zhang Hongyi Xu Guoxian Song You Xie Linjie Luo Yapeng Tian Jiashi Feng Xiaohu Guo 《Computational Visual Media》 2025年第4期763-779,共17页
Generating emotional talking faces from a single portrait image remains a significant challenge. The simultaneous achievement of expressive emotional talking and accurate lip-sync is particularly difficult, as express... Generating emotional talking faces from a single portrait image remains a significant challenge. The simultaneous achievement of expressive emotional talking and accurate lip-sync is particularly difficult, as expressiveness is often compromised for lip-sync accuracy. Prevailing generative works usually struggle to juggle to generate subtle variations of emotional expression and lip-synchronized talking. To address these challenges, we suggest modeling the implicit and explicit correlations between audio and emotional talking faces with a unified framework. As human emotional expressions usually present subtle and implicit relations with speech audio, we propose incorporating audio and emotional style embeddings into the diffusion-based generation process, for realistic generation while concentrating on emotional expressions. We then propose lip-based explicit correlation learning to construct a strong mapping of audio to lip motions, assuring lip-audio synchronization. Furthermore, we deploy a video-to-video rendering module to transfer expressions and lip motions from a proxy 3D avatar to an arbitrary portrait. Both quantitatively and qualitatively, MagicTalk outperforms state-of-the-art methods in terms of expressiveness, lip-sync, and perceptual quality. 展开更多
关键词 emotions talking face generation diffusion model images implicit and explicit correlation learning
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Ammonia Diffusion Phenomena through Nalophan<sup>TM</sup>Bags Used for Olfactometric Analyses
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作者 Selena Sironi Lidia Eusebio +3 位作者 Laura Capelli Emanuela Boiardi Renato Del Rosso Jean-Michel Guillot 《Journal of Environmental Protection》 2014年第11期949-961,共13页
The ammonia loss through NalophanTM bags has been studied. Ammonia was chosen as target compound in order to be representative of odorous molecules of small dimensions. The losses observed for storage conditions and t... The ammonia loss through NalophanTM bags has been studied. Ammonia was chosen as target compound in order to be representative of odorous molecules of small dimensions. The losses observed for storage conditions and times as allowed by the reference standard for dynamic olfactometry (EN 13725:2003) indicate that odour concentration values due to the presence of small molecules may be significantly underestimated if samples are not analysed immediately after sampling. The diffusion coefficient of ammonia through the NalophanTM film was evaluated using the Fick’s law, and it turned out to be equal to 2.38E-12 (m2/s). The results and their theoretical interpretation indicate that concentration losses due to ammonia diffusion through the NalophanTM film can be decreased by using large bags and filling them up to their maximum capacity. 展开更多
关键词 Sampling BAG diffusion Odour Sampling ammonia Nalophan
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Effects of signal modulation and coloured cross-correlation of coloured noises on the diffusion of a harmonic oscillator
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作者 刘立 张良英 曹力 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第10期4182-4186,共5页
The diffusion in a harmonic oscillator driven by coloured noises ξ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expre... The diffusion in a harmonic oscillator driven by coloured noises ξ(t) and η(t) with coloured cross-correlation in which one of the noises is modulated by a biased periodic signal is investigated. The exact expression of diffusion coefficient d as a function of noise parameter, signal parameter, and oscillator frequency is derived. The findings in this paper are as follows. 1) The curves of d versus noise intensity D and d versus noises cross-correlation time z3 exist as two different phases. The transition between the two phases arises from the change of the cross-correlation coefficient A of the two Ornstein-Uhlenbeck (O-U) noises. 2) Changing the value of T3, the curves of d versus Q, the intensity of colored noise that is modulated by the signal, can transform from a phase having a minimum to a monotonic phase. 3) Changing the value of signal amplitude A, d versus Q curves can transform from a phase having a minimum to a monotonic phase. The above-mentioned results demonstrate that a like noise-induced transition appears in the model. 展开更多
关键词 coloured cross-correlation cross-correlation coefficient diffusion coefficient signal modulated noise noise-induced transition
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Extinction Dynamics with the Underlying Physics of Ammonia and Ammonia/Hydrogen Spherical Diffusion Flames in Micro-Gravitational Condition
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作者 KANG Yinhu LIU Junkun +4 位作者 HUANG Xiaomei WU Pengfei JIANG Zhijing ZHANG Jiuyi LU Xiaofeng 《Journal of Thermal Science》 2025年第5期1672-1691,共20页
The utilization of ammonia as an alternative fuel is of great significance in the carbon neutrality strategy. However, the ammonia flame extinction mechanism induced by growing oscillations with its cramped flammabili... The utilization of ammonia as an alternative fuel is of great significance in the carbon neutrality strategy. However, the ammonia flame extinction mechanism induced by growing oscillations with its cramped flammability range, sluggish propagation speed, and poor stability is still not studied in sufficient details. In this paper, the high-fidelity simulations with efficient continuation computation and detailed models are conducted to investigate the ammonia extinction dynamics as a function of hydrogen blending ratio, and to reveal the governing sub-processes in flame extinction and oscillation development. It is found that the extinction and onset of oscillatory instability in the ammonia/hydrogen spherical diffusion flame (SDF) derive from the interaction of competing chemistry with diffusive leakage losses. Chemical oscillations occurring at the maximum temperature iso-contour are primarily responsible for the near-limit flame oscillations. In the rich-side low-temperature region, although the local heat production is inappreciable, the strong diffusive losses with governing, adverse contributions to the ignition chemistry play a leading role in flame extinction. The reactions dominating the extinction limit are also important for the oscillation frequency;the reactions that help to extend the extinction limit also tend to increase the frequency, and vice versa. The extinction limit and frequency depend mainly on the major reactant diffusivities (including NH_(3), H_(2), and O_(2)) and heat conduction, while the diffusivities of other radicals and products are fairly unimportant. Hydrogen addition could remarkably extend the steady-state and oscillatory extinction limits of ammonia SDFs, and reduce the oscillation frequency since the imaginary eigenvalue is depressed. 展开更多
关键词 ammonia HYDROGEN oscillatory extinction spherical diffusion flame flammability limit
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Osmotic membranes for municipal wastewater reclamation:Insights into applications,transmembrane diffusion mechanisms and prospects
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作者 Yujie Xie Kexin Yuan +3 位作者 Beiyang Luo Haoran Feng Xian Bao Jun Ma 《Chinese Chemical Letters》 2025年第7期23-33,共11页
With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade recla... With the global advancement of the circular economy,integrating reverse osmosis(RO)or forward osmosis(FO)with anaerobic membrane bioreactor(AnMBR)offers a promising approach to simultaneously generate high-grade reclaimed water,produce energy,and preserve valuable nutrients from municipal wastewater.However,the selectivity of these osmotic membranes towards ammonia nitrogen,a major component in municipal wastewater and anaerobic effluent,remains unsatisfactory due to its similar polarity and hydraulic radius to water molecules.Therefore,enhancing the ammonia nitrogen rejection of osmotic membranes is imperative to maximize the quality of reclaimed water and minimize the loss of ammonia nitrogen resources.Unfortunately,the current understanding of the mapping relationship between ammonia nitrogen transmembrane diffusion and the micro/nano-structure of osmotic membranes is not systematic,making precise optimization of the membranes challenging.Hence,this review comprehensively analyzed the diffusion behavior of ammonia nitrogen through osmotic membranes to lay the foundation for targeted regulation of membrane fine structure.Initially,the desire for ammonia/ammonium-rejecting membranes was highlighted by introducing current and promising osmotic membrane-based applications in municipal wastewater reclamation processes.Subsequently,the connection between the micro/nano-structure of osmotic membranes and the transmembrane diffusion behavior of ammonia nitrogen was explored by analyzing the effects of membrane characteristics on ammonia nitrogen transport using the DSPM-DE model.Finally,precise methods for modifying membranes to enhance ammonia nitrogen rejection were proposed.This review aims to offer theoretical insights guiding the development of RO and FO membranes with superior ammonia nitrogen rejection for efficient reclamation of municipal wastewater. 展开更多
关键词 Municipal wastewater reclamation Osmotic membrane ammonia nitrogen selectivity Transmembrane diffusion mechanism Optimization strategies
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CORRELATION OF DIFFUSION COEFFICIENTS FOR LIQUIDS AND DENSE FLUIDS WITH TEMPERATURE AND PRESSURE
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作者 刘洪勤 汪文川 卢焕章 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1994年第3期50-59,共10页
On the basis of the free volume theory and activation energy concept,a fundamental equation whichtakes into account the effects of temperature and pressure has been developed.By introducing differentexpressions for th... On the basis of the free volume theory and activation energy concept,a fundamental equation whichtakes into account the effects of temperature and pressure has been developed.By introducing differentexpressions for the free volume and activation energy,several equations for fluid diffusion coefficients were derivedaccordingly.With the van der Waals free volume and intermal energy formula,a three-parameter model for fluiddiffusion coeffficients at moderate pressure was obtained.The grand average absolute deviation percent of 345data points (44 systems)for self-and infinite dilute inter-diffusivities is 2.32,against the results of the model ofCohen and Turnbull,4.13.In particular,by means of the modified Carnahan-Starling free volume equation,afour-parameter model with average abosolute deviation percent 2.64(30 systems,644 data points)for theestimation of dense fluid inter-and self-diffusivities at high pressures and in supercritical conditions was derived.The derived model is superior to the method of 展开更多
关键词 DIFFUSIVITY liquid and DENSE fluid correlation PRESSURE TEMPERATURE free volume ACTIVATION energy
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Heritability of body weight and resistance to ammonia in the Pacific white shrimp Litopenaeus vannamei juveniles 被引量:2
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作者 李文嘉 卢霞 +3 位作者 栾生 罗坤 隋娟 孔杰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第5期1025-1033,共9页
Ammonia,toxic to aquaculture organisms,represents a potential problem in aquaculture systems,and the situation is exacerbated in closed and intensive shrimp farming operations,expecially for Litopenaeus vannamei.Asses... Ammonia,toxic to aquaculture organisms,represents a potential problem in aquaculture systems,and the situation is exacerbated in closed and intensive shrimp farming operations,expecially for Litopenaeus vannamei.Assessing the potential for the genetic improvement of resistance to ammonia in L.vannamei requires knowledge of the genetic parameters of this trait.The heritability of resistance to ammonia was estimated using two descriptors in the present study:the survival time(ST) and the survival status at half lethal time(SS_(50)) for each individual under high ammonia challenge.The heritability of ST and SS_(50) were low(0.154 4±0.044 6 and 0.147 5±0.040 0,respectively),but they were both significantly different from zero(P<0.01).Moreover,these two estimates were basically the same and showed no significant differences from each other(P>0.05),suggesting that ST and SS_(50) could be used as suitable indicators for resistance to ammonia.There were also positive phenotypic and genetic correlation between resistance to ammonia and body weight,which means that resistance to ammonia can be enhanced by the improvement of husbandry practices that increase the body weight.The results from the present study suggest that the selection for higher body weight does not have any negative consequences for resistance to ammonia.In addition to quantitative genetics,tools from molecular genetics can be applied to selective breeding programs to improve the efficiency of selection for traits with low heritability. 展开更多
关键词 Litopenaeus vannamei HERITABILITY resistance to ammonia body weight genetic correlation
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Information diffusion on adaptive network
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作者 胡柯 唐翌 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第10期3536-3541,共6页
Based on the adaptive network, the feedback mechanism and interplay between the network topology and the diffusive process of information are studied. The results reveal that the adaptation of network topology can dri... Based on the adaptive network, the feedback mechanism and interplay between the network topology and the diffusive process of information are studied. The results reveal that the adaptation of network topology can drive systems into the scale-free one with the assortative or disassortative degree correlations, and the hierarchical clustering. Meanwhile, the processes of the information diffusion are extremely speeded up by the adaptive changes of network topology. 展开更多
关键词 adaptive network information diffusion degree correlation hierarchical clustering
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The effect of ammonia on soot formation in ethylene diffusion flames
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作者 WANG QianLong YAN ZhiWen +4 位作者 LI ChaoMin CUI YanQing WEN MingSheng LIU HaiFeng YAO MingFa 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2023年第12期3422-3438,共17页
This paper originally investigates the effect of NH_(3) dilution on soot formation when NH_(3) is gradually added into the fuel stream in an ethylene laminar diffusion flame stabilized on a Santoro burner.The variatio... This paper originally investigates the effect of NH_(3) dilution on soot formation when NH_(3) is gradually added into the fuel stream in an ethylene laminar diffusion flame stabilized on a Santoro burner.The variations of flame diameter and two flame heights,i.e.,mixture-strength flame height and visible flame height are carefully documented and analyzed.Moreover,local soot volume fraction(SVF)and soot temperature fields are simultaneously measured by compact-modulated absorption and emission technique,and the corresponding measurement random errors are also provided by the error propagation calculations for the first time.All the reported measurement random errors of SVF and soot temperature fields are estimated within the range of±0.07–±0.08 ppm and±40–±91 K,respectively.As an original database,the concomitantly measured SVF and soot temperature distributions are provided as high-fidelity datasets for refining soot formation model that is overrode by NH_(3).In addition,the flame cross-section average SVF F_(soot)(z)is calculated for every NH_(3) diluted flame,and the relative contributions of NH_(3) dilution and chemical effect are quantitatively assessed in terms of F_(max)-X_(NH_(3))plotting.It is found that when X_(NH_(3))<30%,the chemical effect of ammonia is about twice that of the dilution effect.While X_(NH_(3))>30%,the chemical effect and dilution effect of ammonia are gradually equal.Eventually,through modeling of the soot formation rate V in the flames,the relative contributions of chemical effect,dilution effect and thermal effect of NH_(3)are further novelty discriminated within the X_(NH_(3))from 0 to 46%and it is shown that NH_(3) chemical effect plays the dominate role in soot suppression,then the dilution effect and the thermal one at the least. 展开更多
关键词 The effect of ammonia on soot formation in ethylene diffusion flames
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Enhancement of water self-diffusion at super-hydrophilic surface with ordered water
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作者 Xiao-Meng Yu Chong-Hai Qi Chun-Lei Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第6期98-102,共5页
It has been well acknowledged that molecular water structures at the interface play an important role in the surface properties, such as wetting behavior or surface frictions. Using molecular dynamics simulation, we s... It has been well acknowledged that molecular water structures at the interface play an important role in the surface properties, such as wetting behavior or surface frictions. Using molecular dynamics simulation, we show that the water self-diffusion on the top of the first ordered water layer can be enhanced near a super-hydrophilic solid surface. This is attributed to the fewer number of hydrogen bonds between the first ordered water layer and water molecules above this layer, where the ordered water structures induce much slower relaxation behavior of water dipole and longer lifetime of hydrogen bonds formed within the first layer. 展开更多
关键词 ordered water layer SELF-diffusion dipole correlation hydrogen bond
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Atlas-based deep gray matter and white matter analysis in Alzheimer's disease: diffusion abnormality and correlation with cognitive function
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作者 覃媛媛 《China Medical Abstracts(Internal Medicine)》 2016年第3期186-,共1页
Objective To identify the diffusion alterations of deep gray matter(GM)and white matter(WM)among Alzheimer’s disease(AD),mild cognitive impairment(MCI)and healthy people by atlas-based analysis(ABA),and to investigat... Objective To identify the diffusion alterations of deep gray matter(GM)and white matter(WM)among Alzheimer’s disease(AD),mild cognitive impairment(MCI)and healthy people by atlas-based analysis(ABA),and to investigate the respective relationship with cognitive function.Methods Twenty-one AD patients(AD group),8 MCI patients(MCI group)and 展开更多
关键词 Atlas-based deep gray matter and white matter analysis in Alzheimer’s disease diffusion abnormality and correlation with cognitive function AD WM MCI DEEP
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In vivo evaluation of early renal damage in type 2 diabetic patients on 3.0 T MR diffusion tensor imaging 被引量:6
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作者 Yu-Ting Wang Xiong Yan +1 位作者 Hong Pu Long-Lin Yin 《World Journal of Radiology》 CAS 2018年第8期83-90,共8页
AIM To investigate the utility of renal diffusion tensor imaging(DTI) to detect early renal damage in patients with type 2 diabetes.METHODS Twenty-six diabetic patients(12 with microalbuminuria(MAU), and 14 with normo... AIM To investigate the utility of renal diffusion tensor imaging(DTI) to detect early renal damage in patients with type 2 diabetes.METHODS Twenty-six diabetic patients(12 with microalbuminuria(MAU), and 14 with normoalbuminuria) and fourteen healthy volunteers were prospectively included in this study. Renal DTI on 3.0 T MR was performed, and estimated glomerular filtration rate(e GFR) was recorded for each subject. Mean cortical and medullary fractional anisotropy(FA) values were calculated by placing multiple representative regions of interest. Mean FA values were statistically compared among groups. Correlations between FA values and e GFR were evaluated. RESULTS Both cortical and medullary FA were significantly reduced in diabetic patients compared to healthy controls(0.403 ± 0.064 vs 0.463 ± 0.047, P = 0.004, and 0.556 ± 0.084 vs 0.645 ± 0.076, P = 0.002, respectively). Cortical FA was significantly lower in diabetic patients with NAU than healthy controls(0.412 ± 0.068 vs 0.463 ± 0.047, P = 0.02). Medullary FA in diabetic patients with NAU and healthy controls were similar(0.582 ± 0.096 vs 0.645 ± 0.076, P = 0.06). Both cortical FA and medullary FA correlated with e GFR(r = 0.382, P = 0.015 and r = 0.552, P = 0.000, respectively).CONCLUSION FA of renal parenchyma on DTI might serve as a more sensitive biomarker of early diabetic nephropathy than MAU. 展开更多
关键词 RENAL diffusion TENSOR imaging Fractional anisotropy DIABETIC NEPHROPATHY MICROALBUMINURIA Estimated GFR correlation
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Application of the Clustering Method in Molecular Dynamics Simulation of the Diffusion Coefficient 被引量:4
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作者 LIU Qingzhi HU Yangdong 《Journal of Ocean University of China》 SCIE CAS 2008年第1期43-47,共5页
Using molecular dynamics (MD) simulation, the diffusion of oxygen, methane, ammonia and carbon dioxide in water was simulated in the canonical NVT ensemble, and the diffusion coefficient was analyzed by the clustering... Using molecular dynamics (MD) simulation, the diffusion of oxygen, methane, ammonia and carbon dioxide in water was simulated in the canonical NVT ensemble, and the diffusion coefficient was analyzed by the clustering method. By comparing to the conventional method (using the Einstein model) and the differentiation-interval variation method, we found that the results ob- tained by the clustering method used in this study are more close to the experimental values. This method proved to be more reason- able than the other two methods. 展开更多
关键词 clustering molecular simulation diffusion coefficient OXYGEN METHANE ammonia carbon dioxide
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Simulation Analysis of Ammonia Leakage and Dispersion in a Large-Scale Refrigeration System 被引量:1
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作者 Jianlu Cheng Kaiyong Hu +3 位作者 Jiang Shen Lu Jia Rui Niu Zhaoxian Yang 《Fluid Dynamics & Materials Processing》 EI 2022年第4期1049-1066,共18页
The use of ammonia in large-scale refrigeration systems(such as those used for a stadium)requires adequate ammonia leakage prevention mechanisms are put in place.In the present study,numerical simulations have been co... The use of ammonia in large-scale refrigeration systems(such as those used for a stadium)requires adequate ammonia leakage prevention mechanisms are put in place.In the present study,numerical simulations have been conducted to study the dispersion law in the ammonia machinery room of the refrigeration system for the 2022 Beijing Winter Olympics.The wind speed,and release location have been varied to investigate their effects on the dispersion profile.Different positions of the leakage points in the ammonia storage tank have been found to lead to different areas affected accordingly.In general,the dangerous region area decreases with an increase in the wind speed.However,when the wind is aligned with the leakage direction,this trend is reverted.The study may offer an effective method to predict the impact of ammonia dispersion and implement the safe operation of such large-scale systems. 展开更多
关键词 Numerical simulation ammonia diffusion leakage location ventilation
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The phenylalanine ammonia-lyase gene family in Isatis indigotica Fort.:molecular cloning,characterization,and expression analysis 被引量:11
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作者 MA Rui-Fang LIU Qian-Zi +4 位作者 XIAO Ying ZHANG Lei LI Qing YIN Jun CHEN Wan-Sheng 《Chinese Journal of Natural Medicines》 SCIE CAS CSCD 2016年第11期801-812,共12页
Phenolic compounds, metabolites of the phenylpropanoid pathway, play an important role in the growth and environmental adaptation of many plants. Phenylalanine ammonia-lyase(PAL) is the first key enzyme of the phenylp... Phenolic compounds, metabolites of the phenylpropanoid pathway, play an important role in the growth and environmental adaptation of many plants. Phenylalanine ammonia-lyase(PAL) is the first key enzyme of the phenylpropanoid pathway. The present study was designed to investigate whether there is a multi-gene family in I. Indigotic and, if so, to characterize their properties. We conducted a comprehensive survey on the transcription profiling database by using tBLASTn analysis. Several bioinformatics methods were employed to perform the prediction of composition and physicochemical characters. The expression levels of IiPAL genes in various tissues of I. indigotica with stress treatment were examined by quantitative real-time PCR. Protoplast transient transformation was used to observe the locations of IiPALs. IiPALs were functionally characterized by expression with pET-32a vector in Escherichia colis strain BL21(DE3). Integration of transcripts and metabolite accumulations was used to reveal the relation between IiPALs and target compounds. An new gene(IiPAL2) was identified and both IiPALs had the conserved enzymatic active site Ala-Ser-Gly and were classified as members of dicotyledon. IiPAL1 and IiPAL2 were expressed in roots, stems, leaves, and flowers, with the highest expression levels of IiPAL1 and IiPAL2 being observed in stems and roots, respectively. The two genes responded to the exogenous elicitor in different manners. Subcellular localization experiment showed that both IiPALs were localized in the cytosol. The recombinant proteins were shown to catalyze the conversion of L-Phe to trans-cinnamic acid. Correlation analysis indicated that Ii PAL1 was more close to the biosynthesis of secondary metabolites than IiPAL2. In conclusion, the present study provides a basis for the elucidation of the role of Ii PALs genes in the biosynthesis of phenolic compounds, which will help further metabolic engineering to improve the accumulation of bioactive components in I.indigotica. 展开更多
关键词 Phenylalanine ammonia-lyase Isatis indigotica Fort Phenolic compounds Lignan correlation analysis
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Photon Correlation Spectroscopy and SAXS Study of Mixture of NaCl with AOT Microemulsion at X = 6.7 被引量:1
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作者 Nahid Karimi Soheil Sharifi Mousa Aliahmad 《Optics and Photonics Journal》 2012年第1期54-58,共5页
Photon Correlation Spectroscopy is used to study the AOT microemulsion with and without NaCl. Collective diffusion coefficient was investigated by Photon Correlation Spectroscopy technique. We have studied effect of c... Photon Correlation Spectroscopy is used to study the AOT microemulsion with and without NaCl. Collective diffusion coefficient was investigated by Photon Correlation Spectroscopy technique. We have studied effect of charge on dynamic of water-in-oil microemulsion (nano-droplet of water to the oil), which stabilized by AOT and dispersed in n-Decane at water/AOT with 6.7 molar ratio. The small angle X-ray scattering technique and hard sphere model were used to study the structural information of AOT microemulsion with and without NaCl. The structural investigation of samples shows a decrease of length scale of cylindrical droplets with increasing of NaCl concentration in AOT microemulsion. 展开更多
关键词 NANO-SIZE DROPLET MICROEMULSIONS Photon correlation Spectroscopy SAXS diffusion
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