期刊文献+
共找到3,366篇文章
< 1 2 169 >
每页显示 20 50 100
Study on the Photostability of Four Preferred UV Absorber Compounds on Colorants
1
作者 Lin Wei Yu Hongliang +4 位作者 Liu Zhuoyuan Wang Zhigang Liu Hao Wang Xuan Xiong Yaodong 《China Detergent & Cosmetics》 2025年第2期45-49,共5页
Color plays an important role in the daily chemical product market,and transparent packaging of daily chemical products are loved by consumers,but it is difficult to avoid fading,discoloration or photodegradation of t... Color plays an important role in the daily chemical product market,and transparent packaging of daily chemical products are loved by consumers,but it is difficult to avoid fading,discoloration or photodegradation of the inner material of the product.UV light is a major contributor to colorant fading,which can affect color stability by damaging chromogenic groups and producing free radicals.In view of this,the combination of four ultraviolet absorbers DHHB,OS,OMC,and MCE was investigated,and the photostability of five common colorants in cosmetics was studied.After 28 days of photostability test,the pigment preservation rate was analyzed,and the results showed that 0.1%of the UV absorber compound could have a certain protective effect on the colorant,and 0.5%of the compound could significantly improve the photostability of the colorant.Adding ultraviolet absorbers to daily chemical products can significantly improve the fading,discoloration or photodegradation of colorants caused by ultraviolet rays. 展开更多
关键词 COSMETICS ultraviolet absorber COLORANT MCE light stability
在线阅读 下载PDF
Natural Colorants:Historical,Processing and Sustainable Prospects 被引量:8
2
作者 Mohd Yusuf Mohd Shabbir Faqeer Mohammad 《Natural Products and Bioprospecting》 CAS 2017年第1期123-145,共23页
With the public’s mature demand in recent times pressurized the textile industry for use of natural colorants,without any harmful effects on environment and aquatic ecosystem,and with more developed functionalities s... With the public’s mature demand in recent times pressurized the textile industry for use of natural colorants,without any harmful effects on environment and aquatic ecosystem,and with more developed functionalities simultaneously.Advanced developments for the natural bio-resources and their sustainable use for multifunctional clothing are gaining pace now.Present review highlights historical overview of natural colorants,classification and predominantly processing of colorants from sources,application on textiles surfaces with the functionalities provided by them.Chemistry of natural colorants on textiles also discussed with relevance to adsorption isotherms and kinetic models for dyeing of textiles. 展开更多
关键词 Natural colorants TEXTILES SUSTAINABILITY PROCESSING Adsorption Application
在线阅读 下载PDF
Facile preparation of nano-g-C_(3)N_(4)/UiO-66-NH_(2) composite as sorbent for high-efficient extraction and preconcentration of food colorants prior to HPLC analysis 被引量:6
3
作者 Xiaowan Zhang Yixin Yang +5 位作者 Peige Qin Lizhen Han Wenli Zhu Shaofeng Duan Minghua Lu Zongwei Cai 《Chinese Chemical Letters》 SCIE CAS CSCD 2022年第2期903-906,共4页
In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,ener... In this work,the nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite was prepared by one-step solvothermal method.The as-prepared composite was characterized by scanning electron microscopy,Brunner-Emmet-Teller measurement,energy dispersive spectrometer,X-ray diffraction,and Fourier transform infrared spectroscopy.By using nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite as sorbent,a dispersive solid-phase extraction coupled with high-performance liquid chromatography was developed to sensitive analysis of food colorants including tartrazine,amaranth,carmine,sunset yellow,allura red and bright blue.The experiment parameters including the amount of sorbent,adsorption time,the p H of adsorption solution,desorption time,desorption solvent,the p H of desorption solution as well as the proportion between desorption solvent and buffer solvent were investigated.Under the optimized conditions,the limits of detection(S/N=3) and limits of quantitation (S/N=10) were determined in the ranges of 0.08-0.8 and 0.2-2.0 ng/m L,respectively.With the developed sample pretreatment method,carmine and brilliant blue were determined from blueberry juice by HPLC-DAD.The contents were calculated as 1.53μg/m L and0.17μg/mL,respectively. 展开更多
关键词 Nano-g-C_(3)N_(4)/Ui O-66-NH_(2)composite Metal-organic frameworks Dispersive solid-phase extraction Sample pretreatment Food colorants Food additives High-performance liquid chromatography
原文传递
The feasibility study of natural pigments as food colorants and seasonings pigments safety on dried tofu coloring 被引量:1
4
作者 Wei-Sheng Lin Pei Hua He +3 位作者 Chi-Fai Chau Bo-Kang Liou Shiming Li Min-Hsiung Pan 《Food Science and Human Wellness》 SCIE 2018年第3期220-228,共9页
In order to improve appetite,attract consumers and even conform to the food culture,food coloring has become one of the necessary links in modern food processing.For example,dried-tofu will be colored by adding artifi... In order to improve appetite,attract consumers and even conform to the food culture,food coloring has become one of the necessary links in modern food processing.For example,dried-tofu will be colored by adding artificial food colors(AFCs)such as sunset yellow,cochineal red A or other seasonings like soy sauce.However,the dispute persists about whether AFCs are harmful to health.Some studies indicate AFCs affect children’s intelligence and attention,cause hyperactivity,and allergy when children consumed≥50 mg.In addition,researches showed that chemical soy sauce produces a trace of methylglyoxal(MGO)in the manufacturing process,which is related to diseases such as oxidative stress,diabetes,and cognitive deterioration.Therefore,natural pigments are relatively new and promising strategy for replacing high-risk AFCs.Thus,the objective of this study was to use dried-tofu as a natural colorants coloring screening platform,through the concept of three primary colors to discuss the coloring effects of natural colorants in Taiwan in double–phase(liquid phase to solid phase)food coloring system and assess the effects of MGO on PC12 neuron cellular morphology and cell cycle at the dietary exposure in soy sauce.Our results showed that formula G:R=0.2:0.8 and C:R=0.08:0.92 were coloring by combined natural colorants had the same eye sensory quality acceptance of consumer and had the intention to purchase.Furthermore,the results from the PC12 cell suggested that dietary exposure of methylglyoxal(<50M)in soy sauce did not affect neuron cellular morphology and cell cycle significantly.Overall,Gardenia Yellow,Curcumin,and Radish Red could overcome the application restrictions in multiplephase food coloring system and simultaneously soy sauce as a coloring agent was safety.It showed the possibility of them as food colorants on dried-tofu. 展开更多
关键词 Natural colorants Dried-tofu The coloring from liquid phase system to solid phase system on dried-tofu
在线阅读 下载PDF
Genotoxicity of Synthetic Food Colorants 被引量:1
5
作者 V. R. Swaroop D. Dinesh Roy T. Vii ayakumar 《Journal of Food Science and Engineering》 2011年第2期128-134,共7页
A study was conducted to evaluate the genotoxicity, if any, of the permitted synthetic food colorants used in India. Eight synthetic food colorants namely Erythrosine (E 127), Tartrazine (E 102), Ponceau 4R (E 12... A study was conducted to evaluate the genotoxicity, if any, of the permitted synthetic food colorants used in India. Eight synthetic food colorants namely Erythrosine (E 127), Tartrazine (E 102), Ponceau 4R (E 124), Sunset Yellow FCF (E 110), Brilliant Blue FCF (E133), Fast Green FCF (E143), Carmoisine (E122) and Indigo Carmine (E132) and their combination are used in sweets namely Ladu, Jilebi and Halwa in Calicut and suburban areas of Kerala, in India. The genotoxicity of the colorants alone and in combinations at different concentrations were evaluated by Cytokinesis Block Micronucleus (CBMN) Assay. It was observed that all the above colorants and their combinations could cause genotoxicity to human lymphocytes even at the permissible concentration of 100 ppm as per PFA (Prevention of Food Adulteration) Act of India. The toxicity varied from dye to dye and was proportional to their concentration. Combination of colors showed more toxicity than the individual components. Toxicity could be reduced drastically by reducing the concentration of the dyes at least 50% below the permissible limit. Permitted synthetic food colorants even at the permissible limit should be used with caution. This study demonstrated the need for redefining the permissible limit of the food colorants based on Admissible Daily Intake (ADI) as being practiced in developed countries. 展开更多
关键词 Synthetic food colorants GENOTOXICITY CBMN (Cytokinesis Block Micronucleus) Assay somatic DNA damage foodadulteration ADI (Admissible Daily Intake).
在线阅读 下载PDF
Natural hydroxyanthraquinoid pigments as potent food grade colorants:an overview 被引量:9
6
作者 Yanis CARO Linda ANAMALE +3 位作者 Mireille FOUILLAUD Philippe LAURENT Thomas PETIT Laurent DUFOSSE 《Natural Products and Bioprospecting》 CAS 2012年第5期174-193,共20页
Natural pigments and colorants are widely used in the world in many industries such as textile dying,food processing or cosmetic manufacturing.Among the natural products of interest are various compounds belonging to ... Natural pigments and colorants are widely used in the world in many industries such as textile dying,food processing or cosmetic manufacturing.Among the natural products of interest are various compounds belonging to carotenoids,anthocyanins,chlorophylls,melanins,betalains...The review emphasizes pigments with anthraquinoid skeleton and gives an overview on hydroxyanthraquinoids described in Nature,the first one ever published.Trends in consumption,production and regulation of natural food grade colorants are given,in the current global market.The second part focuses on the description of the chemical structures of the main anthraquinoid colouring compounds,their properties and their biosynthetic pathways.Main natural sources of such pigments are summarized,followed by discussion about toxicity and carcinogenicity observed in some cases.As a conclusion,current industrial applications of natural hydroxyanthraquinoids are described with two examples,carminic acid from an insect and Arpink red^(™)from a filamentous fungus. 展开更多
关键词 ANTHRAQUINONE hydroxyanthraquinone natural colorant food colorant microbial pigment biotechnology mycotoxin contamination
在线阅读 下载PDF
EFFECTS OF ORGANIC COLORANTS ON PHOTO-INITIATED CROSSLINKING AND PHOTO-OXIDATION DEGRADATION OF POLYETHYLENE AND RELATED MECHANISM 被引量:2
7
作者 瞿保钧 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2008年第3期311-319,共9页
The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism h... The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations,X-ray photoelectron spectroscopy (XPS),mechanical property tests,UV spectroscopy,and light microscope.The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) sample... 展开更多
关键词 COLORANT Photo-initiated crosslinking Photo-oxidative degradation UV irradiation POLYETHYLENE
在线阅读 下载PDF
Identification of Natural and Artificial Colorants in Industrial Products Marketed in Senegal
8
作者 Alé Kane Papa Amadou Diakhaté +3 位作者 Ngoné Fall Bèye Alioune Sow Coumba Gueye Sagna Mady Cissé 《Food and Nutrition Sciences》 2023年第12期1232-1243,共12页
Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated wit... Food colorants are widely used in the food industry to maintain or enhance product color. However, as the use of these colorants can have negative impacts on health, it is essential to analyze the risks associated with their consumption. This analysis requires, among other things, obtaining sufficient data on the presence of these colorants in foods, as well as their level of consumption. However, data on these colorants is often virtually non-existent in developing countries. The aim of this study was to determine the colorant profile of industrial products marketed in Senegal. Information on food additives was collected on 399 labels of different food product categories in shops located in Dakar. Data is recorded and processed using Excel software. Based on the Codex classification, analysis of the profile of additives identified on the labels of food samples revealed the presence of 31 colorants. The natural colorants identified are dominated by beta-carotene, widely present in beverages and dairy products, and paprika extract identified on cookies and industrial sauces. Artificial colors are dominated caramels present in several foods including bouillons, vinegars, sauces and hard candies. Secondly, there was a strong presence of the azo dye Sunset yellow FCF, widely found in samples of beverages, confectionery and cookies. The results of this case study enable us to appreciate the wide presence and diversity of colorants on the Senegalese market, and the importance of controlling them to guarantee consumer safety. 展开更多
关键词 COLORANT Artificial NATURAL Food Additives Food Safety
在线阅读 下载PDF
Rare earth colorants to start production
9
《China Rare Earth Information》 2017年第5期2-3,共2页
Nontoxic colorant from rare earths is expected to be put into full production in the current year in Baotou, the biggest city in the Inner Mongolia autonomous region, following a decision by the local government to up... Nontoxic colorant from rare earths is expected to be put into full production in the current year in Baotou, the biggest city in the Inner Mongolia autonomous region, following a decision by the local government to upgrade the rare earths industry to value-added processes against previously mining the raw materials. "Due to its perfect coloring and nontoxic properties the coloring agent, mainly for plastics and leathers, can replace most existing dyes in the market," said Zhang Hongjie, inventor of the colorant and member of the Chinese Academy of Sciences. 展开更多
关键词 Nontoxic COLORANT from RARE earths is EXPECTED to be PUT into full production in the current year in Baotou
在线阅读 下载PDF
Structural Color Dynamic Graphics Display Based on Microlens Array 被引量:1
10
作者 LI Xue-han LIU Ling-zhi +1 位作者 HUANG Min LI Xiu 《印刷与数字媒体技术研究》 北大核心 2025年第2期162-168,共7页
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be... It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display. 展开更多
关键词 Structural color Microlens array Dynamic graphics display Moirémagnification Optical anti-counterfeiting
在线阅读 下载PDF
Fast full-color pathological imaging using Fourier ptychographic microscopy via closed-form model-based colorization 被引量:2
11
作者 Yanqi Chen Jiurun Chen +4 位作者 Zhiping Wang Yuting Gao Yonghong He Yishi Shi An Pan 《Advanced Photonics Nexus》 2025年第2期7-16,共10页
Full-color imaging is essential in digital pathology for accurate tissue analysis.Utilizing advanced optical modulation and phase retrieval algorithms,Fourier ptychographic microscopy(FPM)offers a powerful solution fo... Full-color imaging is essential in digital pathology for accurate tissue analysis.Utilizing advanced optical modulation and phase retrieval algorithms,Fourier ptychographic microscopy(FPM)offers a powerful solution for high-throughput digital pathology,combining high resolution,large field of view,and extended depth of field(DOF).However,the full-color capabilities of FPM are hindered by coherent color artifacts and reduced computational efficiency,which significantly limits its practical applications.Color-transferbased FPM(CFPM)has emerged as a potential solution,theoretically reducing both acquisition and reconstruction threefold time.Yet,existing methods fall short of achieving the desired reconstruction speed and colorization quality.In this study,we report a generalized dual-color-space constrained model for FPM colorization.This model provides a mathematical framework for model-based FPM colorization,enabling a closed-form solution without the need for redundant iterative calculations.Our approach,termed generalized CFPM(gCFPM),achieves colorization within seconds for megapixel-scale images,delivering superior colorization quality in terms of both colorfulness and sharpness,along with an extended DOF.Both simulations and experiments demonstrate that gCFPM surpasses state-of-the-art methods across all evaluated criteria.Our work offers a robust and comprehensive workflow for high-throughput full-color pathological imaging using FPM platforms,laying a solid foundation for future advancements in methodology and engineering. 展开更多
关键词 Fourier ptychographic microscopy color transfer dual-color-space constrained model
在线阅读 下载PDF
Identification and molecular marker development for peel color gene in melon(Cucumis melo L.) 被引量:1
12
作者 Jian Ma Guoliang Yuan +4 位作者 Xinyang Xu Haijun Zhang Yanhong Qiu Congcong Li Huijun Zhang 《Journal of Integrative Agriculture》 2025年第7期2589-2600,共12页
Peel color is an important appearance quality of melons that significantly affects consumer preferences.In this study,a near-isogenic line NIL-G(dark green peel)was generated from B8(grey-green peel)and B15(white peel... Peel color is an important appearance quality of melons that significantly affects consumer preferences.In this study,a near-isogenic line NIL-G(dark green peel)was generated from B8(grey-green peel)and B15(white peel).The F_2 population constructed by crossing NIL-G and B15 was used to study the inheritance pattern of peel color,and bulked-segregant analysis sequencing(BSA-seq)was employed to identify the interval in which the target gene was located.Genetic analysis showed that a dominant gene controls the dark green peel trait at maturity.BSAseq and molecular markers were used to localize the candidate gene in a 263.7 kb interval of chromosome 4,which contained the CmAPRR2 gene with known functions.Moreover,allelic sequence analysis revealed four SNP variations of the CmAPRR2 gene in B15,of which SNP.G614331A was located at the junction of the 6th exon and 6th intron.The G-to-A mutation caused alternative splicing of the transcript of CmAPRR2 in B15,generating two transcripts(CmAPRR2-A and CmAPRR2-B)with premature termination codons.Furthermore,the Kompetitive Allele Specific PCR(KASP)marker,APRR2-G/A,was developed based on this SNP and shown to co-segregate with the peel color phenotype in the F_(2) population.Compared to white-peel B15,the expression level of CmAPRR2 in dark green peel NIL-G was higher at each growth stage.Therefore,CmAPRR2 may be the key gene controlling the fruit color of melons.This study identified a novel allelic variant of CmAPRR2 that leads to white peel formation in mature melons.We also provides a theoretical basis for further research on the gene regulatory mechanism of melon peel colors,which promotes using molecular marker-assisted selection to modify melon peel colors in the future. 展开更多
关键词 MELON BSA-seq MAPPING CmAPRR2 peel color KASP marker
在线阅读 下载PDF
Dynamic Structural Colors in Helical Superstructures:from Supramolecules to Polymers 被引量:1
13
作者 Bo Ji Lang Qin Yan-Lei Yu 《Chinese Journal of Polymer Science》 2025年第3期406-428,共23页
Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.... Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.This dynamic color-changing capability is crucial for applications that require adaptable optical properties,positioning CLCs as key materials in advanced photonic technologies.This review focuses on the mechanisms of dynamic color tuning in CLCs across various forms,including small molecules,cholesteric liquid crystal elastomers(CLCEs),and cholesteric liquid crystal networks(CLCNs),and emphasizes the distinct responsive coloration each structure provides.Key developments in photochromic mechanisms based on azobenzene,dithienylethene,and molecular motor switches,are discussed for their roles in enhancing the stability and tuning range of CLCs.We examine the color-changing behaviors of CLCEs under mechanical stimuli and CLCNs under swelling,highlighting the advantages of each form.Following this,applications of dynamic color-tuning CLCs in information encryption,adaptive camouflage,and smart sensing technologies are explored.The review concludes with an outlook on current challenges and future directions in CLC research,particularly in biomimetic systems and dynamic photonic devices,aiming to broaden their functional applications and impact. 展开更多
关键词 Structural colors Cholesteric liquid crystals Elastomers Polymer network
原文传递
Nanograting‑Based Dynamic Structural Colors Using Heterogeneous Materials
14
作者 Jingang Wang Haibo Yu +6 位作者 Jianchen Zheng Yuzhao Zhang Hongji Guo Ye Qiu Xiaoduo Wang Yongliang Yang Lianqing Liu 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期138-151,共14页
Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,prov... Dynamic structuralcolors can change in response todifferent environmental stimuli.This ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and microfluidics.However, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips. 展开更多
关键词 Dynamic structural colors Four-dimensional printing PH-RESPONSIVE Nanogrid Heterogeneous materials
在线阅读 下载PDF
The telomere-to-telomere gap-free genome assembly of Juglans sigillata 被引量:1
15
作者 Delu Ning Tao Wu +7 位作者 Wenlong Lei Shengcheng Zhang Ting Ma Li Pan Liangjun Xiao Noor-ul-Ain Xingtan Zhang Fuliang Cao 《Horticultural Plant Journal》 2025年第4期1551-1563,共13页
Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness,including essential nutrients,antioxidants,and healthy fats,which boost human cardial,brain and gut health.Despite its impor... Juglans sigillata is an economically valuable nut crop renowned for its nutritional richness,including essential nutrients,antioxidants,and healthy fats,which boost human cardial,brain and gut health.Despite its importance,the lack of a complete genome assembly has been a stumbling block in its biological breeding process.Therefore,we generated deep coverage ultralong Oxford Nanopore Technology(ONT)and PacBio HiFi reads to construct a telomere-to-telomere(T2T)genome assembly.The final assembly spans 537.27 Mb with no gaps,demonstrating a remarkable completeness of 98.1%.We utilized a combination of transcriptome data and homologous proteins to annotate the genome,identifying 36018 protein-coding genes.Furthermore,we profiled global cytosine DNA methylations using ONT sequencing data.Global methylome analysis revealed high methylation levels in transposable element(TE)-rich chromosomal regions juxtaposed with comparatively lower methylation in gene-rich areas.By integrating a detailed multi-omics data analysis,we obtained valuable insights into the mechanism underlying endopleura coloration.This investigation led to the identification of eight candidate genes(e.g.ANR)involved in anthocyanin biosynthesis pathways,which are crucial for the development of color in plants.The comprehensive genome assembly and the understanding of the genetic basis of important traits like endopleura coloration will open avenues for more efficient breeding programs and improved crop quality. 展开更多
关键词 Juglans sigillata Telomere-to-telomere(T2T)genome assembly Global methylation Endopleura color
在线阅读 下载PDF
Robust Backstepping Control of a Quadrotor Unmanned Aerial Vehicle under Colored Noises
16
作者 Mehmet Karahan 《Computers, Materials & Continua》 SCIE EI 2025年第1期777-798,共22页
Advances in software and hardware technologies have facilitated the production of quadrotor unmanned aerial vehicles(UAVs).Nowadays,people actively use quadrotor UAVs in essential missions such as search and rescue,co... Advances in software and hardware technologies have facilitated the production of quadrotor unmanned aerial vehicles(UAVs).Nowadays,people actively use quadrotor UAVs in essential missions such as search and rescue,counter-terrorism,firefighting,surveillance,and cargo transportation.While performing these tasks,quadrotors must operate in noisy environments.Therefore,a robust controller design that can control the altitude and attitude of the quadrotor in noisy environments is of great importance.Many researchers have focused only on white Gaussian noise in their studies,whereas researchers need to consider the effects of all colored noises during the operation of the quadrotor.This study aims to design a robust controller that is resistant to all colored noises.Firstly,a nonlinear quadrotormodel was created with MATLAB.Then,a backstepping controller resistant to colored noises was designed.Thedesigned backstepping controller was tested under Gaussian white,pink,brown,blue,and purple noises.PID and Lyapunov-based controller designswere also carried out,and their time responses(rise time,overshoot,settling time)were compared with those of the backstepping controller.In the simulations,time was in seconds,altitude was in meters,and roll,pitch,and yaw references were in radians.Rise and settling time values were in seconds,and overshoot value was in percent.When the obtained values are examined,simulations prove that the proposed backstepping controller has the least overshoot and the shortest settling time under all noise types. 展开更多
关键词 Backstepping control colored noises Gaussian noise Lyapunov stability QUADROTOR ROBUSTNESS PID control
在线阅读 下载PDF
Preheating detoxification of flaxseed and its impact on the quality of flaxseed
17
作者 ZHOU Junzhuo CHU Pengfei +5 位作者 DONG Guimei PEI Xuechen HUANG Jiaqian ZHENG Rui YIN Fawen ZHOU Dayong 《中国油脂》 北大核心 2025年第6期11-22,30,共13页
Aiming to provide a theoretical basis for possible uses of flaxseed as a food supplement and functional ingredient, the heat treatment of flaxseed was carried out using steaming, roasting, and microwave methods to inv... Aiming to provide a theoretical basis for possible uses of flaxseed as a food supplement and functional ingredient, the heat treatment of flaxseed was carried out using steaming, roasting, and microwave methods to investigate the detoxification effects of these three pretreatment methods on flaxseed, as well as the impact of the three methods on the quality of flaxseed. The results showed that all three pretreatment methods had better detoxification effects on flaxseed, in which, microwave treatment was the most effective method. After 5 min of microwave treatment, the hydrogen cyanide(HCN) content in flaxseed decreased from(94.65±1.68) mg/kg to(7.80±0.57) mg/kg. All three pretreatment methods significantly reduced the water content in flaxseed but had a weaker effect on protein, fat, and ash contents. After pretreatment by the three methods, the polyphenol content, peroxide value(POV), and a*value of flaxseed increased significantly, thiobarbituric acid reactive substances(TBARS) increased, while polyunsaturated fatty acids(PUFA) content, amino acid content, and L*, W*, and b*values decreased, with varying degrees of wrinkles and cracks appearing on the surface of flaxseed, and the overall signal pattern of FTIR spectra did not change much. During the 40℃ accelerated storage process, the quality of flaxseed treated by all three preheating methods generally declined, and correlation analysis revealed that color change was a good indicator of quality changes in flaxseed. Notably, all three pretreatment methods extended the shelf-life of flaxseed. Compared with steaming(120℃ for 20 min) and roasting(100℃ for 40 min), microwave(560 W for 4 min) is recommended to remove cyanogenic glycosides and improve the stability and quality characteristics of flaxseed. 展开更多
关键词 FLAXSEED DETOXIFICATION POLYPHENOL COLOR stability ACCELERATED storage
在线阅读 下载PDF
Ramsey numbers of edge-critical graphs versus large generalized fans
18
作者 Taiping Jiang Xinmin Hou 《中国科学技术大学学报》 北大核心 2025年第5期62-66,61,I0002,共7页
Given two graphs G and H,the Ramsey number R(G,H)is the smallest positive integer N such that every 2-coloring of the edges of K_(N)contains either a red G or a blue H.Let K_(N-1)■K_(1,k)be the graph obtained from K_... Given two graphs G and H,the Ramsey number R(G,H)is the smallest positive integer N such that every 2-coloring of the edges of K_(N)contains either a red G or a blue H.Let K_(N-1)■K_(1,k)be the graph obtained from K_(N-1)by adding anew vertexνconnecting k vertices of K_(N-1).A graph G withχ(G)=k+1 is called edge-critical if G contains an edge e such thatχ(G-e)=k.A considerable amount of research has been conducted by previous scholars on Ramsey numbers ofgraphs.In this study,we show that for an edge-critical graph G with x(G)=k+1,when k≥2,1≥2,and n is sufficiently large,R(G,K_(1)+nK_(t))=knt+1 and r,(G,K_(1)+nK_(t))=(k-1)nt+1. 展开更多
关键词 Ramsey number color critical graph generalized fan
在线阅读 下载PDF
Patterned Three-Dimensional Photonic Crystal Structures Based on Paper Substrates
19
作者 WANG Ye-qi LI Xiu +1 位作者 HUANG Min LIU Yu 《印刷与数字媒体技术研究》 北大核心 2025年第4期62-69,共8页
In the printing industry,the common method of coloring relies on inks,which contains amounts of chemical agents,causing environment pollution.However,structural color achieves coloration through the refraction and dif... In the printing industry,the common method of coloring relies on inks,which contains amounts of chemical agents,causing environment pollution.However,structural color achieves coloration through the refraction and diffraction of light by periodic structure,offering eco-friendly and fade-resistant advantages,as well as colorful.In this study,screen printing was used to create patterned mask on paper substrates.Then,coated SiO_(2)microspheres on the mask to create structural color patterns with angle-dependent color characteristics.The patterns showed color changes from rose-red to orange to green by changing the viewing angle.By changing the color grayscale,the absorption of stray light by the substrate was enhanced,thereby the brightness and saturation of the structural color improved too.This method is simple,cost-effective,and environmentally friendly,and it has highly promising for the application in printing and anti-counterfeiting. 展开更多
关键词 Photonic crystal Structural color Screen printing SiO_(2)microsphere Environmental protection
在线阅读 下载PDF
Research on Printing Preferences for Skin Color
20
作者 WANG Dan GONG Xu-ping +1 位作者 SHANG Xiao-yu HUANG Min 《印刷与数字媒体技术研究》 北大核心 2025年第1期46-52,共7页
In order to study the preferred skin color for printing images,two CMYK images from ISO 400 and one from iStock,including five skin color images of East Asian females was selected in this study.The images were adjuste... In order to study the preferred skin color for printing images,two CMYK images from ISO 400 and one from iStock,including five skin color images of East Asian females was selected in this study.The images were adjusted with the CMYK printing ink volume variation of the single,double and triple channels in the given 280%total ink limit conditions.A larger number of color vision normal observers were organized to carry out the color preference evaluation experiment,and the selected preferred skin colors were analyzed.The distribution range of the chromaticity values for skin color images were obtained and the results indicated that there are three regions for printing skin color preferences,and the observers have a memory preference for brighter,fairer skin colors in young female and a reddish skin colors in girl,which can provide the guidance for color adjustment of printed skin color images. 展开更多
关键词 Preferred skin color Printing images Total ink limit CMYK ink adjustment
在线阅读 下载PDF
上一页 1 2 169 下一页 到第
使用帮助 返回顶部