期刊文献+
共找到106篇文章
< 1 2 6 >
每页显示 20 50 100
Analysis of Heat Transfer Phenomenon in Magnetohydrodynamic Casson Fluid Flow Through Cattaneo–Christov Heat Diffusion Theory 被引量:7
1
作者 G. K. Ramesh J. Gireesha, +1 位作者 S. A. shehzad, F. M. Abbasi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2017年第7期91-95,共5页
Heat transport phenomenon of two-dimensional magnetohydrodynamie Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated... Heat transport phenomenon of two-dimensional magnetohydrodynamie Casson fluid flow by employing Cattaneo-Christov heat diffusion theory is described in this work. The term of heat absorption/generation is incorporated in the mathematical modeling of present flow problem. The governing mathematical expressions are solved for velocity and temperature profiles using RKF 45 method along with shooting technique. The importance of arising nonlinear quantities namely velocity, temperature, skin-friction and temperature gradient are elaborated via plots. It is explored that the Casson parameter retarded the liquid velocity while it enhances the fluid temperature. Fhrther, we noted that temperature and thickness of temperature boundary layer are weaker in case of Cattaneo-Christov heat diffusion model when matched with the profiles obtained for Fourier's theory of heat flux. 展开更多
关键词 Hydromagnetic flow Casson fluid heat transfer Cattaneo-Christov heat diffusion model numer-ical solution
原文传递
Boundary layer flow of third grade nanofluid with Newtonian heating and viscous dissipation 被引量:8
2
作者 S.A.shehzad Tariq Hussain +2 位作者 T.Hayat M.Ramzan A.Alsaedi 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期360-367,共8页
Two-dimensional boundary layer flow of an incompressible third grade nanofluid over a stretching surface is investigated.Influence of thermophoresis and Brownian motion is considered in the presence of Newtonian heati... Two-dimensional boundary layer flow of an incompressible third grade nanofluid over a stretching surface is investigated.Influence of thermophoresis and Brownian motion is considered in the presence of Newtonian heating and viscous dissipation.Governing nonlinear problems of velocity, temperature and nanoparticle concentration are solved via homotopic procedure.Convergence is examined graphically and numerically. Results of temperature and nanoparticle concentration are plotted and discussed for various values of material parameters, Prandtl number, Lewis number, Newtonian heating parameter, Eckert number and thermophoresis and Brownian motion parameters. Numerical computations are performed. The results show that the change in temperature and nanoparticle concentration distribution functions is similar when we use higher values of material parameters β1 andβ2. It is seen that the temperature and thermal boundary layer thickness are increasing functions of Newtonian heating parameter γ.An increase in thermophoresis and Brownian motion parameters tends to an enhancement in the temperature. 展开更多
关键词 third grade nanofluid Newtonian heating viscous dissipation
下载PDF
1%吡美莫司乳膏联合多磺粘多糖乳膏治疗面部糖皮质激素依赖性皮炎疗效观察 被引量:5
3
作者 童海涛 吴桥芳 +2 位作者 shehzad Gopee 阚敬保 尹智 《中国美容医学》 CAS 2020年第12期30-33,共4页
目的:观察外用吡美莫司乳膏联合多磺粘多糖乳膏治疗面部糖皮质激素依赖性皮炎的有效性和安全性。方法:选取2016年1月-2020年1月笔者科室就诊的面部糖皮质激素依赖性皮炎患者,随机分为联合组及对照组,联合组:患者外用1%吡美莫司乳膏与多... 目的:观察外用吡美莫司乳膏联合多磺粘多糖乳膏治疗面部糖皮质激素依赖性皮炎的有效性和安全性。方法:选取2016年1月-2020年1月笔者科室就诊的面部糖皮质激素依赖性皮炎患者,随机分为联合组及对照组,联合组:患者外用1%吡美莫司乳膏与多磺粘多糖乳膏;对照组:患者单用1%吡美莫司乳膏,共4周。比较两组患者的疗效、不良反应及复发情况等。结果:完成4周治疗后,联合组多项客观症状及自觉症状评分好转程度均优于对照组,且差异有统计学意义(P<0.05),两组患者的复发率比较无统计学差异(P>0.05)。结论:1%吡美莫司乳膏联合多磺粘多糖乳膏治疗面部糖皮质激素依赖性皮炎安全、有效。 展开更多
关键词 吡美莫司 多磺粘多糖 糖皮质激素依赖性皮炎 戒断
下载PDF
Experimental Investigation of Immiscible Supercritical Carbon Dioxide Foam Rheology for Improved Oil Recovery 被引量:8
4
作者 shehzad Ahmed Khaled Abdalla Elraies +4 位作者 Jalal Foroozesh Siti Rohaida Bt Mohd Shafian Muhammad Rehan Hashmet Ivy Chai Ching Hsia Abdullah Almansour 《Journal of Earth Science》 SCIE CAS CSCD 2017年第5期835-841,共7页
This paper presents the rheological behaviour of supercritical CO2 (sCO2) foam at reser- voir conditions of I 500 psi and 80 ℃. Different commercial surfactants were screened and utilized in or- der to generate a f... This paper presents the rheological behaviour of supercritical CO2 (sCO2) foam at reser- voir conditions of I 500 psi and 80 ℃. Different commercial surfactants were screened and utilized in or- der to generate a fairly stable CO2 foam. Mixed surfactant system was also introduced to generate strong foam. Foam rheology was studied for some specific foam qualities using a high pressure high tempera- ture (HPHT) foam loop rheometer. A typical shear thinning behaviour of the foam was observed and a significant increase in the foam viscosity was noticed with the increase of foam quality until 85%. A de- sired high apparent viscosity with coarse texture was found at 85% foam quality. Foam visualization above 85% showed an unstable foam due to extremely thin lamella which collapsed and totally disap- peared in the loop rheometer. Below 52%, a non-homogenous and unstable foam was found having low viscosity with some liquid accumulation at the bottom of the circulation loop. This research has demon- strated rheology of sCO2 foams at different qualities at HPHT to obtain optimal foam quality region for immiscible CO2 foam co-injection process. 展开更多
关键词 supercritical CO2 foam apparent viscosity foam quality foam stability.
原文传递
Efficacy of Low Dose Naltrexone on Pain Reduction in Chronic Pain Syndromes: A Meta Analysis
5
作者 Haroutiun Hamzoian shehzad Choudry 《Pain Studies and Treatment》 2023年第3期15-25,共11页
Chronic pain is a multifaceted debilitating experience often associated with significant physical and emotional burden. Low dose naltrexone (LDN) has gained attention in recent years for its potential utility in the m... Chronic pain is a multifaceted debilitating experience often associated with significant physical and emotional burden. Low dose naltrexone (LDN) has gained attention in recent years for its potential utility in the management of fibromyalgia, irritable bowel syndrome, multiple sclerosis, and painful diabetic neuropathy. LDN’s analgesic effects have been associated with its ability to increase the production of endorphins while reducing the production of tumor necrosis factor-alpha, interleukin-6, reactive oxygen species and nitric oxide. This meta-analysis aims to systematically review and synthesize the available evidence on efficacy of LDN as an analgesic in pain syndromes, with a focus on chronic (neuro) inflammatory diseases. The goal is to provide clinicians with a more comprehensive estimate of the effectiveness of LDN as a non-opioid option for managing chronic pain and guide future research in the area. Thirteen randomized control trials, published from 1990 to 2022, were selected for the analysis that satisfied inclusion criteria. The overall effects in these studies were calculated using the standardized mean difference (SMD) between the LDN and placebo groups. We found an overall SMD of -10.77 (95% CI: -13.96 to -7.58) with a p-value of 0.002. This indicated that the LDN group experienced a statistically significant reduction in pain compared to placebo. This meta-analysis provides evidence for the potential efficacy of low dose naltrexone in reducing pain and enhancing analgesia in various pain syndromes. LDN may be a useful treatment option for patients suffering from chronic pain, particularly with fibromyalgia, multiple sclerosis, or diabetic neuropathy. However, further research is needed to confirm the efficacy and safety of low dose naltrexone for chronic pain conditions, especially with larger sample sizes, standardized dosing regimens and treatment durations. 展开更多
关键词 Pain Management LDN PAIN ANESTHESIOLOGY NEUROLOGY Low Dose Naltrexone Chronic Pain
下载PDF
MHD three-dimensional flow of Jeffrey fluid with Newtonian heating 被引量:6
6
作者 S.A.shehzad T.Hayat +1 位作者 M.S.Alhuthali S.Asghar 《Journal of Central South University》 SCIE EI CAS 2014年第4期1428-1433,共6页
The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the... The magnetohydrodynamic(MHD) three-dimensional flow of Jeffrey fluid in the presence of Newtonian heating is investigated. Flow is caused by a bidirectional stretching surface. Series solutions are constructed for the velocity and temperature fields. Convergence of series solutions is ensured graphically and numerically. The variations of key parameters on the physical quantities are shown and discussed in detail. Constructed series solutions are compared with the existing solutions in the limiting case and an excellent agreement is noticed. Nusselt numbers are computed with and without magnetic fields. It is observed that the Nusselt number decreases in the presence of magnetic field. 展开更多
关键词 three-dimensional flow Jeffrey fluid Newtonian heating
下载PDF
Model Agnostic Meta-Learning(MAML)-Based Ensemble Model for Accurate Detection of Wheat Diseases Using Vision Transformer and Graph Neural Networks
7
作者 Yasir Maqsood Syed Muhammad Usman +3 位作者 Musaed Alhussein Khursheed Aurangzeb shehzad Khalid Muhammad Zubair 《Computers, Materials & Continua》 SCIE EI 2024年第5期2795-2811,共17页
Wheat is a critical crop,extensively consumed worldwide,and its production enhancement is essential to meet escalating demand.The presence of diseases like stem rust,leaf rust,yellow rust,and tan spot significantly di... Wheat is a critical crop,extensively consumed worldwide,and its production enhancement is essential to meet escalating demand.The presence of diseases like stem rust,leaf rust,yellow rust,and tan spot significantly diminishes wheat yield,making the early and precise identification of these diseases vital for effective disease management.With advancements in deep learning algorithms,researchers have proposed many methods for the automated detection of disease pathogens;however,accurately detectingmultiple disease pathogens simultaneously remains a challenge.This challenge arises due to the scarcity of RGB images for multiple diseases,class imbalance in existing public datasets,and the difficulty in extracting features that discriminate between multiple classes of disease pathogens.In this research,a novel method is proposed based on Transfer Generative Adversarial Networks for augmenting existing data,thereby overcoming the problems of class imbalance and data scarcity.This study proposes a customized architecture of Vision Transformers(ViT),where the feature vector is obtained by concatenating features extracted from the custom ViT and Graph Neural Networks.This paper also proposes a Model AgnosticMeta Learning(MAML)based ensemble classifier for accurate classification.The proposedmodel,validated on public datasets for wheat disease pathogen classification,achieved a test accuracy of 99.20%and an F1-score of 97.95%.Compared with existing state-of-the-art methods,this proposed model outperforms in terms of accuracy,F1-score,and the number of disease pathogens detection.In future,more diseases can be included for detection along with some other modalities like pests and weed. 展开更多
关键词 Wheat disease detection deep learning vision transformer graph neural network model agnostic meta learning
下载PDF
Design of an Efficient and Provable Secure Key Exchange Protocol for HTTP Cookies
8
作者 Waseem Akram Khalid Mahmood +3 位作者 Hafiz Burhan ul Haq Muhammad Asif shehzad Ashraf Chaudhry Taeshik Shon 《Computers, Materials & Continua》 SCIE EI 2024年第7期263-280,共18页
Cookies are considered a fundamental means of web application services for authenticating various Hypertext Transfer Protocol(HTTP)requests andmaintains the states of clients’information over the Internet.HTTP cookie... Cookies are considered a fundamental means of web application services for authenticating various Hypertext Transfer Protocol(HTTP)requests andmaintains the states of clients’information over the Internet.HTTP cookies are exploited to carry client patterns observed by a website.These client patterns facilitate the particular client’s future visit to the corresponding website.However,security and privacy are the primary concerns owing to the value of information over public channels and the storage of client information on the browser.Several protocols have been introduced that maintain HTTP cookies,but many of those fail to achieve the required security,or require a lot of resource overheads.In this article,we have introduced a lightweight Elliptic Curve Cryptographic(ECC)based protocol for authenticating client and server transactions to maintain the privacy and security of HTTP cookies.Our proposed protocol uses a secret key embedded within a cookie.The proposed protocol ismore efficient and lightweight than related protocols because of its reduced computation,storage,and communication costs.Moreover,the analysis presented in this paper confirms that proposed protocol resists various known attacks. 展开更多
关键词 COOKIES authentication protocol impersonation attack ECC
下载PDF
Multiplicity dependence of the freezeout parameters in high energy hadron-hadron collisions
9
作者 Muhammad Ajaz Majid shehzad +7 位作者 Muhammad Waqas Haifa I.Alrebdi Mohammad Ayaz Ahmad Antalov Jagnandan Shawn Jagnandan Murad Badshah Jalal Hasan Baker Abdul Mosawir Quraishi 《Chinese Physics C》 SCIE CAS CSCD 2024年第5期124-133,共10页
We examined the transverse momentum(pT)spectra of various identified particles,encompassing both light-flavored and strange hadrons(π++π−,K++K−,p+p¯,ϕ,K0s,Λ+Λ¯,Ξ−+Ξ¯+,andΩ−+Ω¯+),across diff... We examined the transverse momentum(pT)spectra of various identified particles,encompassing both light-flavored and strange hadrons(π++π−,K++K−,p+p¯,ϕ,K0s,Λ+Λ¯,Ξ−+Ξ¯+,andΩ−+Ω¯+),across different multiplicity classes in proton-proton collisions(p-p)at a center-of-mass energy of s√=7 TeV.Utilizing the Tsallis and Hagedorn models,parameters relevant to the bulk properties of nuclear matter were extracted.Both models exhibit good agreement with experimental data.In our analyses,we observed a consistent decrease in the effective temperature(T)for the Tsallis model and the kinetic or thermal freeze-out temperature(T0)for the Hagedorn model,as we transitioned from higher multiplicity(class-I)to lower multiplicity(class-X).This trend is attributed to the diminished energy transfer in higher multiplicity classes.Additionally,we observed that the transverse flow velocity(βT)experiences a decline from class-I to class-X.The normalization constant,which represents the multiplicity of produced particles,was observed to decrease as we moved toward higher multiplicity classes.While the effective and kinetic freeze-out temperatures,as well as the transverse flow velocity,show a mild dependency on multiplicity for lighter particles,this dependency becomes more pronounced for heavier particles.The multiplicity parameter for heavier particles was observed to be smaller than that of lighter particles,indicating a greater abundance of lighter hadrons compared to heavier ones.Various particle species were observed to undergo decoupling from the fireball at distinct temperatures:lighter particles exhibit lower temperatures,while heavier ones show higher temperatures,thereby supporting the concept of multiple freeze-out scenarios.Moreover,we identified a positive correlation between the kinetic freeze-out temperature and transverse flow velocity,a scenario where particles experience stronger collective motion at a higher freeze-out temperature.The reason for this positive correlation is that,as the multiplicity i 展开更多
关键词 multiplicity dependence collective properties thermal energy
原文传递
Convective heat and mass transfer in MHD mixed convection flow of Jeffrey nanofluid over a radially stretching surface with thermal radiation 被引量:6
10
作者 M.BILAL ASHRAF T.HAYAT +1 位作者 A.ALSAEDI S.A.shehzad 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第3期1114-1123,共10页
Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary condi... Mixed convection flow of magnetohydrodynamic(MHD) Jeffrey nanofluid over a radially stretching surface with radiative surface is studied. Radial sheet is considered to be convectively heated. Convective boundary conditions through heat and mass are employed. The governing boundary layer equations are transformed into ordinary differential equations. Convergent series solutions of the resulting problems are derived. Emphasis has been focused on studying the effects of mixed convection, thermal radiation, magnetic field and nanoparticles on the velocity, temperature and concentration fields. Numerical values of the physical parameters involved in the problem are computed for the local Nusselt and Sherwood numbers are computed. 展开更多
关键词 Jeffrey nanofluid mixed convection flow radially stretching surface convective boundary conditions magnetic field
下载PDF
Cocrystals of carbamazepine:Structure,mechanical properties,fluorescence properties,solubility,and dissolution rate
11
作者 Jinbo Ouyang Lishan Liu +5 位作者 Yin Li Mingyang Chen Limin Zhou Zhirong Liu Li Xu Hamza shehzad 《Particuology》 SCIE EI CAS CSCD 2024年第7期20-30,共11页
Carbamazepine(CBZ)is an anticonvulsant with very low water solubility,presenting as a white crystalline powder with poor mechanical properties and is hard to bend.To enhance CBZ's physicochemical properties,such a... Carbamazepine(CBZ)is an anticonvulsant with very low water solubility,presenting as a white crystalline powder with poor mechanical properties and is hard to bend.To enhance CBZ's physicochemical properties,such as water solubility and mechanical properties,we selected six cocrystal coformers(CCFs):nicotinamide(NIC),benzamide(BZM),salicylic acid(SCA),fumaric acid(FMA),trimesic acid(TMA),and hesperetin(HPE).Six CBZ cocrystals were successfully prepared using the solution method.Fourier transform infrared spectroscopy(FT-IR),powder X-ray diffraction(PXRD),differential scanning calorimetry(DSC),and single crystal X-ray diffraction(SCXRD)were used to characterize the crystal structures and gain comprehensive insights into the six cocrystals.The mechanical,fluorescence,and solubility properties of the six cocrystals were tested.The results reveal that most of the prepared cocrystals exhibit improved water solubility and mechanical properties when compared to CBZ.Among them,the dissolution rate of cocrystals excluded from CBZ-HPE has increased by an average of 3 or 4 times compared to CBZ,while CBZ-HPE exhibits superior mechanical properties.Moreover,all six cocrystals possess better fluorescence performance than CBZ.We thoroughly evaluated the mechanical properties of the cocrystals through both experimental and theoretical approaches.This work provides a new direction for studying drug cocrystals to improve the physicochemical properties of drugs. 展开更多
关键词 CARBAMAZEPINE COCRYSTAL Mechanical properties Fluorescence performance Dissolution rate
原文传递
Deep-learning-assisted online surface roughness monitoring in ultraprecision fly cutting
12
作者 shehzad Adeel RUI XiaoTing +4 位作者 DING YuanYuan ZHANG JianShu CHANG Yu LU HanJing CHEN YiHeng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第5期1482-1497,共16页
Surface roughness is one of the most critical attributes of machined components,especially those used in high-performance systems.Online surface roughness monitoring offers advancements comparable to post-process insp... Surface roughness is one of the most critical attributes of machined components,especially those used in high-performance systems.Online surface roughness monitoring offers advancements comparable to post-process inspection methods,reducing inspection time and costs and concurrently reducing the likelihood of defects.Currently,online monitoring approaches for surface roughness are constrained by several limitations,including the reliance on handcrafted feature extraction,which necessitates the involvement of human experts and entails time-consuming processes.Moreover,the prediction models trained under one set of cutting conditions exhibit poor performance when applied to different experimental settings.To address these challenges,this work presents a novel deep-learning-assisted online surface roughness monitoring method for ultraprecision fly cutting of copper workpieces under different cutting conditions.Tooltip acceleration signals were acquired during each cutting experiment to develop two datasets,and no handcrafted features were extracted.Five deep learning models were developed and evaluated using standard performance metrics.A convolutional neural network stacked on a long short-term memory network outperformed all other network models,yielding exceptional results,including a mean absolute percentage error as low as 1.51%and an R2value of 96.6%.Furthermore,the robustness of the proposed model was assessed via a validation cohort analysis using experimental data obtained using cutting parameters different from those previously employed.The performance of the model remained consistent and commendable under varied conditions,asserting its applicability in real-world scenarios. 展开更多
关键词 online surface roughness monitoring UPFC deep learning CNN-LSTM vibration signal
原文传递
Engineering Leaf-Like UiO-66-SO3H Membranes for Selective Transport of Cations 被引量:6
13
作者 Tingting Xu Muhammad Aamir shehzad +3 位作者 Xin Wang Bin Wu Liang Ge Tongwen Xu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2020年第4期65-75,共11页
Metal–organic frameworks(MOFs)with angstrom-sized pores are promising functional nanomaterials for the fabrication of cation permselective membranes(MOF-CPMs).However,only a few research reports show successful prepa... Metal–organic frameworks(MOFs)with angstrom-sized pores are promising functional nanomaterials for the fabrication of cation permselective membranes(MOF-CPMs).However,only a few research reports show successful preparation of the MOF-CPMs with good cation separation performance due to several inherent problems in MOFs,such as arduous selfassembly,poor water resistance,and tedious fabrication strategies.Besides,low cation permeation flux due to the absence of the cation permeation assisting functionalities in MOFs is another big issue,which limits their widespread use in membrane technology.Therefore,it is necessary to fabricate functional MOF-CPMs using simplistic strategies to improve cation permeation.In this context,we report a facile in situ smart growth strategy to successfully produce ultrathin(<600 nm)and leaflike UiO-66-SO3H membranes at the surface of anodic alumina oxide.The physicochemical characterizations confirm that sulfonated angstrom-sized ion transport channels exist in the as-prepared UiO-66-SO3H membranes,which accelerate the cation permeation(~3×faster than non-functionalized UiO-66 membrane)and achieve a high ion selectivity(Na^+/Mg^2+>140).The outstanding cation separation performance validates the importance of introducing sulfonic acid groups in MOF-CPMs. 展开更多
关键词 Metal–organic frameworks In situ smart growth UiO-66-SO3H membrane Ion separation
下载PDF
A revised Cattaneo-Christov micropolar viscoelastic nanofluid model with combined porosity and magnetic effects 被引量:5
14
作者 S.A.shehzad S.U.KHAN +1 位作者 Z.ABBAS A.RAUF 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第3期521-532,共12页
The dynamics of non-Newtonian fluids along with nanoparticles is quite interesting with numerous industrial applications. The current predominately predictive modeling deals with the flow of the viscoelastic micropola... The dynamics of non-Newtonian fluids along with nanoparticles is quite interesting with numerous industrial applications. The current predominately predictive modeling deals with the flow of the viscoelastic micropolar fluid in the presence of nanoparticles. A progressive amendment in the heat and concentration equations is made by exploiting the Cattaneo-Christov(C-C) heat and mass flux expressions. Besides, the thermal radiation effects are contributed in the energy equation and aspect of the radiation parameter, and the Prandtl number is specified by the one-parameter approach.The formulated expressions are converted to the dimensionless forms by relevant similarity functions. The analytical solutions to these expressions have been erected by the homotopy analysis method. The variations in physical quantities, including the velocity,the temperature, the effective local Nusselt number, the concentration of nanoparticles,and the local Sherwood number, have been observed under the influence of emerging parameters. The results have shown good accuracy compared with those of the existing literature. 展开更多
关键词 micropolar viscoelastic fluid nanoparticle thermal radiation Cattaneo-Christov(C-C)theory porous medium
下载PDF
提升小波变换与分形结合的图像压缩算法 被引量:5
15
作者 马俐 赵红东 +2 位作者 Hafiz shehzad Ahmed 彭晓灿 韩铁成 《电视技术》 北大核心 2017年第2期11-15,共5页
遥感图像在环境监测、军事侦察等多方面有着广泛应用,然而遥感图像包含信息量大,对其进行压缩来提高存储效率具有重要意义。传统分形编码由于压缩比大的特点被广泛应用到遥感图像压缩中,但是传统分形编码存在压缩时间太长的问题。提出... 遥感图像在环境监测、军事侦察等多方面有着广泛应用,然而遥感图像包含信息量大,对其进行压缩来提高存储效率具有重要意义。传统分形编码由于压缩比大的特点被广泛应用到遥感图像压缩中,但是传统分形编码存在压缩时间太长的问题。提出提升小波变换与改进分形结合的压缩方法,把提升小波变换后的低频分量进行基于最小方差搜索法的分形压缩。实验结果表明,提升小波变换与改进的分形结合的压缩方法与小波变换与分形结合的压缩方法相比,在峰值信噪比保持在35 d B不变的情况下,压缩时间大约可以缩短8倍,图像压缩比也有提高。 展开更多
关键词 提升小波变换 遥感图像 分形编码
下载PDF
Efficacious selective separation of U(Ⅵ) over Mo(Ⅵ) using novel 2,9-diamide-1,10-phenanthroline ligands: Liquid-liquid extraction and coordination chemistry 被引量:1
16
作者 Taoyuan Xiu Simei Zhang +11 位作者 Peng Ren Siyan Liu Shuai Wang Hamza shehzad Jingyang Wang Meng Zhang Guoan Ye Caishan Jiao Qunyan Wu Liyong Yuan Zhifang Chai Weiqun Shi 《Chinese Chemical Letters》 SCIE CAS CSCD 2023年第11期163-168,共6页
Uranium and molybdenum are important strategic elements. The production of ^(99)Mo and the hydrometallurgical process of uranium ore face difficult problems of separation of uranium and molybdenum.In this study, the f... Uranium and molybdenum are important strategic elements. The production of ^(99)Mo and the hydrometallurgical process of uranium ore face difficult problems of separation of uranium and molybdenum.In this study, the four phenanthroline diamide ligands were synthesized, and extraction and stripping experiments were performed under different conditions to evaluate the potential application of these ligands for separation of U(Ⅵ) over Mo(Ⅵ). With the growth of alkyl chain, the solubility of ligands could be greatly improved, and the separation effect of U(Ⅵ) over Mo(Ⅵ) gradually increased. The SF_(U/Mo) were around 10,000 at 4 mol/L HNO3. Three stripping agents were tested with the stripping efficiency of Na_(2)CO_(3)(5%) > H_(2)O > HNO_(3)(0.01 mol/L). The stripping percentages of the three stripping agents were all close to unity, indicating that the ligands had the potential to be recycled. The chemical stoichiometry of U(Ⅵ) complexes with ligands was evaluated as 1:1 using electrospray ionization mass spectrometry,ultraviolet visible spectroscopy and single-crystal X-ray diffraction. The consistency between theoretical calculation and experimental results further explains the coordination mechanism. 展开更多
关键词 Phenanthroline diamide ligand URANIUM MOLYBDENUM Solvent extraction Coordination chemistry
原文传递
Multiscale simulations of growth-dominated Sb2Te phase-change material for non-volatile photonic applications 被引量:1
17
作者 Xu-Dong Wang Wen Zhou +5 位作者 Hangming Zhang shehzad Ahmed Tiankuo Huang Riccardo Mazzarello En Ma Wei Zhang 《npj Computational Materials》 SCIE EI CSCD 2023年第1期928-936,共9页
Chalcogenide phase-change materials(PCMs)are widely applied in electronic and photonic applications,such as non-volatile memory and neuro-inspired computing.Doped Sb2Te alloys are now gaining increasing attention for ... Chalcogenide phase-change materials(PCMs)are widely applied in electronic and photonic applications,such as non-volatile memory and neuro-inspired computing.Doped Sb2Te alloys are now gaining increasing attention for on-chip photonic applications,due to their growth-driven crystallization features.However,it remains unknown whether Sb2Te also forms a metastable crystalline phase upon nanoseconds crystallization in devices,similar to the case of nucleation-driven Ge-Sb-Te alloys.Here,we carry out ab initio simulations to understand the changes in optical properties of amorphous Sb2Te upon crystallization and post annealing.During the continuous transformation process,changes in the dielectric function are highly wavelength-dependent from the visible-light range towards the telecommunication band.Our finite-difference time-domain simulations based on the ab initio input reveal key differences in device output for color display and photonic memory applications upon tellurium ordering.Our work serves as an example of how multiscale simulations of materials can guide practical photonic phase-change applications. 展开更多
关键词 TRANSFORMATION CRYSTALLIZATION PHASE
原文传递
超微粉碎对藕节膳食纤维理化性质的影响 被引量:5
18
作者 金文筠 Hussain shehzad +2 位作者 严守雷 王清章 李洁 《食品安全质量检测学报》 CAS 2015年第6期2071-2076,共6页
目的研究超微粉碎对藕节理化性质的影响,增强其膳食纤维的生理功能,提高可溶性膳食纤维含量。方法在不同研磨条件下,采用激光粒度法测定其粒度,采用化学法测定持水性、持油性、溶胀性,酶重法测定可溶性膳食纤维含量。结果超微粉碎可显... 目的研究超微粉碎对藕节理化性质的影响,增强其膳食纤维的生理功能,提高可溶性膳食纤维含量。方法在不同研磨条件下,采用激光粒度法测定其粒度,采用化学法测定持水性、持油性、溶胀性,酶重法测定可溶性膳食纤维含量。结果超微粉碎可显著减小物料粒径。随着粒度的减小,持油性、持水性、溶胀性及可溶性膳食纤维含量呈上升趋势。当研磨条件为研磨时间12 h、介质物料比8%、转速300 r/min时,粒度显著减小至15.3μm(P<0.05)。在此条件下,藕节膳食纤维持油性、持水性、溶胀性分别为2.23 g/g、3.62 g/g、5.97 mL/g。可溶性膳食纤维含量从3.55%显著提高至11.20%(P<0.05),比未超微粉碎提高了2.16倍。结论超微粉碎能有效降低藕节膳食纤维粒度,显著增加可溶性膳食纤维含量,并赋予其优良的理化性质,为藕节渣综合利用提供相关依据。 展开更多
关键词 超微粉碎 藕节 膳食纤维 粒度 理化性质 可溶性膳食纤维
下载PDF
Mixed Convection Stagnation Point Flow of Casson Fluid with Convective Boundary Conditions 被引量:5
19
作者 T.Hayat S.A.shehzad +1 位作者 A.Alsaedi M.S.Alhothuali 《Chinese Physics Letters》 SCIE CAS CSCD 2012年第11期148-151,共4页
The mixed convection stagnation-point flow of an incompressible non-Newtonian fluid over a stretching sheet under convective boundary conditions is investigated.Mathematical formulation is presented for a Casson fluid... The mixed convection stagnation-point flow of an incompressible non-Newtonian fluid over a stretching sheet under convective boundary conditions is investigated.Mathematical formulation is presented for a Casson fluid.The resulting partial differential equations are converted into the ordinary differential equations by the suitable transformations.The velocity and temperature profiles are computed by employing the homotopy analysis method.The plotted graphs illustrate the flow and heat transfer characteristics and their dependence upon the embedded parameters.Numerical values of skin-friction coefficient and Nusselt number are given and examined.Comparison of the present results with the existing solution is also given. 展开更多
关键词 METHOD STRETCHING ordinary
下载PDF
不同土壤氮水平下C_(3)和C_(4)植物之间的菌根网络及氮传递 被引量:1
20
作者 Muhammad Atif Muneer Xiaohui Chen +6 位作者 Muhammad Zeeshan Munir Zaib-Un Nisa Muhammad Abu Bakar Saddique shehzad Mehmood Da Su Chaoyuan Zheng Baoming Ji 《Journal of Plant Ecology》 SCIE CSCD 2023年第2期28-38,共11页
丛枝菌根真菌(AMF)的菌丝在土壤中通常可以链接相同或不同物种的植物根系,所形成的菌根网络可以将养分从一种植物传递到另一种植物。然而,土壤中的氮(N)含量对不同植物物种之间通过菌根网络进行养分转移的影响尚未实验验证。为了定量研... 丛枝菌根真菌(AMF)的菌丝在土壤中通常可以链接相同或不同物种的植物根系,所形成的菌根网络可以将养分从一种植物传递到另一种植物。然而,土壤中的氮(N)含量对不同植物物种之间通过菌根网络进行养分转移的影响尚未实验验证。为了定量研究不同土壤氮水平下羊草(LC)和糙隐子草(CS)之间通过菌根网络的养分转移,本研究建立了两个分室盆栽系统,即CS–LC系统(CS和LC分别为供体和受体)和LC–CS系统(LC和CS分别为供体和受体),设置了3种土壤氮添加水平,即不添加氮对照(N0)、添加7 mg/kg(N1)和添加14 mg/kg(N2)。通过在供体植物一侧土壤添加稳定同位素^(15)N,示踪并量化不同物种植物幼苗之间通过菌根网络传递的氮。在CS–LC系统中,AMF侵染率、菌丝密度和植物生物量在N1水平最高;而在LC–CS系统,AMF侵染率、菌丝密度和植物生物量在N2水平达到最大。此外,在CS–LC系统中,^(15)N转移率介于16%到61%之间,在N1水平最大。对于LC–CS系统,^(15)N传输速率相对较低,最大值出现在N0水平。这些发现表明,土壤中的氮含量能够调控供体植物和受体植物之间经由菌根网络传递的氮养分。 展开更多
关键词 菌根网络 氮传递 差异响应 糙隐子草(Cleistogene squarrosa) 羊草(Leymus chinensis) 典型草原
原文传递
上一页 1 2 6 下一页 到第
使用帮助 返回顶部