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Smart Cellulose‑Based Janus Fabrics with Switchable Liquid Transportation for Personal Moisture and Thermal Management
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作者 Jianfeng Xi Yanling Lou +5 位作者 Liucheng Meng Chao Deng Youlu Chu Zhaoyang Xu Huining Xiao Weibing Wu 《Nano-Micro Letters》 SCIE EI CAS 2025年第1期333-347,共15页
The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of mana... The Janus fabrics designed for personal moisture/thermal regulation have garnered significant attention for their potential to enhance human comfort.However,the development of smart and dynamic fabrics capable of managing personal moisture/thermal comfort in response to changing external environments remains a challenge.Herein,a smart cellulose-based Janus fabric was designed to dynamically manage personal moisture/heat.The cotton fabric was grafted with N-isopropylacrylamide to construct a temperature-stimulated transport channel.Subsequently,hydrophobic ethyl cellulose and hydrophilic cellulose nanofiber were sprayed on the bottom and top sides of the fabric to obtain wettability gradient.The fabric exhibits anti-gravity directional liquid transportation from hydrophobic side to hydrophilic side,and can dynamically and continuously control the transportation time in a wide range of 3–66 s as the temperature increases from 10 to 40℃.This smart fabric can quickly dissipate heat at high temperatures,while at low temperatures,it can slow down the heat dissipation rate and prevent the human from becoming too cold.In addition,the fabric has UV shielding and photodynamic antibacterial properties through depositing graphitic carbon nitride nanosheets on the hydrophilic side.This smart fabric offers an innovative approach to maximizing personal comfort in environments with significant temperature variations. 展开更多
关键词 Directional water transport Cotton fabric Anti-gravity directional liquid transportation Janus wettability
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木质素基脱落酸缓释微胶囊的制备及其在纸基地膜中的应用
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作者 刘超 张威健 +5 位作者 李雨 王雨婷 盖晓倩 计磊 卞辉洋 肖惠宁 《精细化工》 EI CAS CSCD 北大核心 2024年第12期2754-2765,共12页
对木质素磺酸钠(SL)进行胺基化改性得到了胺基化木质素磺酸钠(ASL),然后,采用十二烷基苯磺酸钠(SDBS)对ASL进行表面改性制备了ASL/SDBS微球。利用自组装技术将植物生长调节剂脱落酸(ABA)装载于ASL/SDBS微球中,制备了以ASL/SDBS为壁材、... 对木质素磺酸钠(SL)进行胺基化改性得到了胺基化木质素磺酸钠(ASL),然后,采用十二烷基苯磺酸钠(SDBS)对ASL进行表面改性制备了ASL/SDBS微球。利用自组装技术将植物生长调节剂脱落酸(ABA)装载于ASL/SDBS微球中,制备了以ASL/SDBS为壁材、ABA为芯材的木质素基脱落酸(ABA@ASL)微胶囊。以ABA@ASL微胶囊和棕榈蜡乳液为涂布材料,通过涂布技术制备了功能性纸基地膜。采用纳米粒度及Zeta电位分析仪、SEM、TEM、FTIR考察了m(SDBS)/m(ASL)对制备的ASL/SDBS微球的Zeta电位、微观形貌、结构组成的影响。通过载药量、包封率测定和药物缓释、抗光解性能测试,探究了壁芯比(即ASL/SDBS与ABA的质量比,下同)对ABA@ASL微胶囊载药和缓释的影响;采用水蒸气透过率、水接触角测定和模拟土壤环境的温度、相对湿度变化以及降解实验,分析了棕榈蜡涂布量对功能性纸基地膜性能的影响。结果表明,当壁芯比为1∶1时,制备的ABA@ASL-2微胶囊载药量为32%,包封率为58%,72 h药物释放率仅为49.3%,72 h的紫外线照射下药物保留率可达75.1%。ABA@ASL微胶囊分散液和棕榈蜡乳液的涂布量为3 g/m^(2)制备的地膜-3性能最佳,其水接触角达到103°,干抗张能量吸收值达到50.98 J/m^(2),湿抗张能量吸收值为11.84 J/m^(2);相比于第0 d,经地膜-3覆盖7 d后的地下5 cm土壤相对湿度保留率超过50%,其地下5 cm土壤保温性能与聚乙烯地膜相当。经土壤埋藏降解实验,纸基地膜在90 d内基本完全降解,降解产物对环境无污染。 展开更多
关键词 木质素 脱落酸 载药微胶囊 纸基地膜 药物缓释 功能材料
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Hepatolithiasis:Epidemiology,presentation,classification and management of a complex disease 被引量:5
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作者 Rodrigo V.Motta Francesca Saffioti Vasileios K Mavroeidis 《World Journal of Gastroenterology》 SCIE CAS 2024年第13期1836-1850,共15页
The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic ... The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management. 展开更多
关键词 CHOLELITHIASIS Intrahepatic stones Cholangiocarcinoma Biliary parasites Recurrent pyogenic cholangitis Oriental cholangiohepatitis Hepatectomy CHOLANGIOSCOPY Liver transplant PAEDIATRIC
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Effects of excess high-normal alanine aminotransferase levels in relation to new-onset metabolic dysfunction-associated fatty liver disease:Clinical implications 被引量:1
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作者 Giovanna McGinty Robert Przemioslo 《World Journal of Gastroenterology》 SCIE CAS 2024年第27期3264-3267,共4页
In this editorial,we comment on the article by Chen et al recently published in 2024.We focus the debate on whether reducing the upper limit of normal of alanine aminotransferase(ALT)would effectively identify cases o... In this editorial,we comment on the article by Chen et al recently published in 2024.We focus the debate on whether reducing the upper limit of normal of alanine aminotransferase(ALT)would effectively identify cases of fibrosis in metabolic-dysfunction associated fatty liver disease(MAFLD).This is important given the increasing prevalence of MAFLD and obesity globally.Currently,a suitable screening test to identify patients in the general population does not exist and most patients are screened after the finding of an abnormal ALT.The authors of this paper challenge the idea of what a normal ALT is and whether that threshold should be lowered,particularly as their study found that 83.12%of their study population with a diagnosis of MAFLD had a normal ALT.The main advantages of screening would be to identify patients and provide intervention early,the mainstay of this being changing modifiable risk factors and monitoring for liver fibrosis.However,there is not enough suitable therapeutic options available as of yet although this is likely to change in the coming years with more targets for therapy being discovered.Semaglutide is one example of this which has demonstrated benefit with an acceptable side effect profile for those patients with MAFLD and obesity,although studies have not yet shown a significant improvement in fibrosis regression.It would also require a huge amount of resource if a reduced ALT level alone was used as criteria;it is more likely that current scoring systems such as fibrosis-4 may be amended to represent this additional risk.Currently,there is not a good argument to recommend wide-spread screening with a reduced ALT level as this is unlikely to be cost-effective.This is compounded by the fact that there is a significant heterogeneity in what is considered a normal ALT between laboratories.Although studies previously have suggested a more pragmatic approach in screening those over the age of 60,this is likely to change with the increasing incidence of obesity within the younger age groups.The main message from this study is that those who have hypercholesterolemia and high body metabolic index should have these risk factors modified to maintain a lower level of ALT to reduce the risk of progression to fibrosis and cirrhosis. 展开更多
关键词 Alanine aminotransferase Metabolic-dysfunction associated fatty liver disease Metabolic syndrome Fibrosis Cirrhosis Semaglutide
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An oxygenating colloidal bioink for the engineering of biomimetic tissue constructs 被引量:1
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作者 Seol-Ha Jeong Jarno Hiemstra +9 位作者 Patrick V.Blokzijl Rebeca Damian-Ferrara Danilo Martins dos Santos Jéssica H.L.da Fonseca Min-Ho Kang Jihyun Kim Dilara Yilmaz-Aykut Mei L.L.Cham-Pérez Jeroen Leijten Su Ryon Shin 《Bio-Design and Manufacturing》 SCIE EI CAS CSCD 2024年第3期240-261,共22页
Ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural regeneration.Variation in oxygen concentration among diverse tissues necessita... Ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural regeneration.Variation in oxygen concentration among diverse tissues necessitates the precise recreation of tissue-specific oxygen levels in imprinted constructs to support the survival of targeted cells.Although oxygen-releasing biomaterials,such as oxygen-generating microparticles(OMPs),have shown promise for enhancing the oxygen supply of microenvironments in injured tissues,whether this approach is scalable for large tissues and whether tissue-specific bioinks with varying OMP concentrations remain printable remain unknown.This study addresses this critical gap by introducing an innovative class of engineered oxygenated bioinks that combine colloidal-based microgels with OMPs.We report that incorporating nanosized calcium peroxide(nCaO_(2))and manganese oxide nanosheets(nMnO_(2))into hydrophobic polymeric microparticles enables precise modulation of oxygen release while controlling hydrogen peroxide release.Moreover,the fabrication of oxygenating and cytocompatible colloidal gels is achieved using an aqueous two-phase system.This study thoroughly evaluates the fundamental characteristics of the resulting bioink,including its rheological behaviors,printability,shape fidelity,mechanical properties,and oxygen release properties.Moreover,this study demonstrates the macroscopic scalability and cytocompatibility of printed constructs produced via cell-laden oxygenating colloidal bioinks.By showcasing the effectiveness of extrusion-based bioprinting,this study underscores how it can be used to fabricate biomimetic tissues,indicating its potential for new applications.The findings presented here advance the bioprinting field by achieving scalability with both high cell viability and the possibility of mimicking specifically oxygenated tissues.This work thereby offers a promising avenue for the development of functional tissues with enhanced physiological relevance. 展开更多
关键词 3D bioprinting Bioink Colloidal gels Extrusion printing Oxygen-generating microparticle
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Island biogeography theory and the habitat heterogeneity jointly explain global patterns of Rhododendron diversity
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作者 Yanwei Guan Yongru Wu +4 位作者 Zheng Cao Zhifeng Wu Fangyuan Yu Haibin Yu Tiejun Wang 《Plant Diversity》 SCIE CAS CSCD 2024年第5期565-574,共10页
Mountain biodiversity is of great importance to biogeography and ecology.However,it is unclear what ecological and evolutionary processes best explain the generation and maintenance of its high levels of species diver... Mountain biodiversity is of great importance to biogeography and ecology.However,it is unclear what ecological and evolutionary processes best explain the generation and maintenance of its high levels of species diversity.In this study,we determined which of six common hypotheses(e.g.,climate hypotheses,habitat heterogeneity hypothesis and island biogeography theory)best explain global patterns of species diversity in Rhododendron.We found that Rhododendron diversity patterns were most strongly explained by proxies of island biogeography theory(i.e.,mountain area)and habitat heterogeneity(i.e.,elevation range).When we examined other relationships important to island biogeography theory,we found that the planimetric area and the volume of mountains were positively correlated with the Rhododendron diversity,whereas the‘mountains-to-mainland’distance was negatively correlated with Rhododendron diversity and shared species.Our findings demonstrate that Rhododendron diversity can be explained by island biogeography theory and habitat heterogeneity,and mountains can be regarded as islands which supported island biogeography theory. 展开更多
关键词 Mountain biodiversity RHODODENDRON Island biogeography theory Habitat heterogeneity Biogeographical hypotheses Plant diversity
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Seasonal changes in Hermit Thrush (Catharus guttatus) song syntax
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作者 Sean P.Roach Luke C.McLean +1 位作者 Jeff W.MacLeod Leslie S.Phillmore 《Avian Research》 SCIE CSCD 2024年第2期172-179,共8页
In many songbird species,birdsong features phonological syntax,meaning that the units within their vocal se-quences are ordered in a non-random way that adheres to a rule.While such syntactical patterns have been rich... In many songbird species,birdsong features phonological syntax,meaning that the units within their vocal se-quences are ordered in a non-random way that adheres to a rule.While such syntactical patterns have been richly described in many species,comparatively little is known about how those patterns contribute to song achieving its important functions.For each of song’s main functions,territorial defense and mate attraction,evidence of a role for syntax is limited.One species for which syntax has been thoroughly described is the Hermit Thrush(Catharus guttatus),which presents song types from their repertoires in a semi-predictable order and,in doing so,rapidly cycle up and down the frequency spectrum.The objective of the present study was to explore the importance of song syntax in the Hermit Thrush through a within-subject examination of how measures of syntax,such as the predictability of song type order within song sequences,shift over the breeding season.We hypothesized that,if such syntactical characteristics are important to breeding behaviour,they would be most prominent at the start of the breeding season when activity associated with territory establishment and mate attraction is most intense.Analysis revealed that,as predicted,the rigidness of song type ordering within se-quences was highest at the start of the season and declined thereafter.That song type sequences were most predictable at the vitally important early part of the breeding season fit our hypothesis that this aspect of song syntax is important to song’s functions related to territory establishment and/or mate attraction.Future work will clarify whether that role relates to one of song’s two main functions or serves song transmission in some broader way. 展开更多
关键词 BIRDSONG Hermit Thrush Seasonal change STEREOTYPY SYNTAX
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What diameter?What height?Influence of measures of average tree size on area-based allometric volume relationships
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作者 Yilin Wang John A.Kershaw +2 位作者 Mark J.Ducey Yuan Sun James B.McCarter 《Forest Ecosystems》 SCIE CSCD 2024年第1期100-109,共10页
Volume is an important attribute used in many forest management decisions.Data from 83 fixed-area plots located in central New Brunswick,Canada,are used to examine how different measures of stand-level diameter and he... Volume is an important attribute used in many forest management decisions.Data from 83 fixed-area plots located in central New Brunswick,Canada,are used to examine how different measures of stand-level diameter and height influence volume prediction using a stand-level variant of Honer's(1967)volume equation.When density was included in the models(Volume=f(Diameter,Height,Density))choice of diameter measure was more important than choice of height measure.When density was not included(Volume=f(Diameter,Height)),the opposite was true.For models with density included,moment-based estimators of stand diameter and height performed better than all other measures.For models without density,largest tree estimators of stand diameter and height performed better than other measures.The overall best equation used quadratic mean diameter,Lorey's height,and density(root mean square error=5.26 m^3·ha^(-1);1.9%relative error).The best equation without density used mean diameter of the largest trees needed to calculate a stand density index of 400 and the mean height of the tallest 400 trees per ha(root mean square error=32.08 m^(3)·ha^(-1);11.8%relative error).The results of this study have some important implications for height subsampling and LiDAR-derived forest inventory analyses. 展开更多
关键词 Allometric relationships Stand structure Volume estimation Stand-level attributes
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New indices to balanceα-diversity against tree size inequality
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作者 Li Zhang Brady K.Quinn +4 位作者 Cang Hui Meng Lian Johan Gielis Jie Gao Peijian Shi 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第1期229-237,共9页
The number and composition of species in a community can be quantified withα-diversity indices,including species richness(R),Simpson’s index(D),and the Shannon-Wiener index(H΄).In forest communities,there are large ... The number and composition of species in a community can be quantified withα-diversity indices,including species richness(R),Simpson’s index(D),and the Shannon-Wiener index(H΄).In forest communities,there are large variations in tree size among species and individu-als of the same species,which result in differences in eco-logical processes and ecosystem functions.However,tree size inequality(TSI)has been largely neglected in studies using the available diversity indices.The TSI in the diameter at breast height(DBH)data for each of 99920 m×20 m forest census quadrats was quantified using the Gini index(GI),a measure of the inequality of size distribution.The generalized performance equation was used to describe the rotated and right-shifted Lorenz curve of the cumulative proportion of DBH and the cumulative proportion of number of trees per quadrat.We also examined the relationships ofα-diversity indices with the GI using correlation tests.The generalized performance equation effectively described the rotated and right-shifted Lorenz curve of DBH distributions,with most root-mean-square errors(990 out of 999 quadrats)being<0.0030.There were significant positive correlations between each of threeα-diversity indices(i.e.,R,D,and H’)and the GI.Nevertheless,the total abundance of trees in each quadrat did not significantly influence the GI.This means that the TSI increased with increasing spe-cies diversity.Thus,two new indices are proposed that can balanceα-diversity against the extent of TSI in the com-munity:(1−GI)×D,and(1−GI)×H’.These new indices were significantly correlated with the original D and H΄,and did not increase the extent of variation within each group of indices.This study presents a useful tool for quantifying both species diversity and the variation in tree sizes in forest communities,especially in the face of cumulative species loss under global climate change. 展开更多
关键词 Diameter at breast height(DBH) Gini index Shannon-Wiener index Simpson’s index QUADRAT Tree size
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Pancreatic surgery and tertiary pancreatitis services warrant provision for support from a specialist diabetes team
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作者 Vasileios K Mavroeidis Jennifer Knapton +1 位作者 Francesca Saffioti Daniel L Morganstein 《World Journal of Diabetes》 SCIE 2024年第4期598-605,共8页
Pancreatic surgery units undertake several complex operations,albeit with consi-derable morbidity and mortality,as is the case for the management of complicated acute pancreatitis or chronic pancreatitis.The centralis... Pancreatic surgery units undertake several complex operations,albeit with consi-derable morbidity and mortality,as is the case for the management of complicated acute pancreatitis or chronic pancreatitis.The centralisation of pancreatic surgery services,with the development of designated large-volume centres,has contribu-ted to significantly improved outcomes.In this editorial,we discuss the complex associations between diabetes mellitus(DM)and pancreatic/periampullary disease in the context of pancreatic surgery and overall management of complex pancreatitis,highlighting the consequential needs and the indispensable role of specialist diabetes teams in support of tertiary pancreatic services.Type 3c pan-creatogenic DM,refers to DM developing in the setting of exocrine pancreatic disease,and its identification and management can be challenging,while the glycaemic control of such patients may affect their course of treatment and outcome.Adequate preoperative diabetes assessment is warranted to aid identification of patients who are likely to need commencement or escalation of glucose lowering therapy in the postoperative period.The incidence of new onset diabetes after pancreatic resection is widely variable in the literature,and depends on the type and extent of pancreatic resection,as is the case with pancreatic parenchymal loss in the context of severe pancreatitis.Early involvement of a specialist diabetes team is essential to ensure a holistic management.In the current era,large volume pancreatic surgery services commonly abide by the principles of enhanced recovery after surgery,with inclusion of provisions for optimisation of the perioperative glycaemic control,to improve outcomes.While various guidelines are available to aid perioperative management of DM,auditing and quality improvement platforms have highlighted deficiencies in the perioperative management of diabetic patients and areas of required improvement.The need for perioperative support of diabetic patients by specialist diabetes teams is uniformly underlined,a fact that becomes clearly more prominent at all different stages in the setting of pancreatic surgery and the management of complex pancreatitis.Therefore,pancreatic surgery and tertiary pancreatitis services must be designed with a provision for support from specialist diabetes teams.With the ongoing accumulation of evidence,it would be reasonable to consider the design of specific guidelines for the glycaemic management of these patients. 展开更多
关键词 PANCREATECTOMY PANCREATODUODENECTOMY Whipple’s PANCREATITIS Diabetes specialist Type 3c pancreatogenic diabetes mellitus
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Ensemble Modeling for the Classification of Birth Data
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作者 Fiaz Majeed Abdul Razzaq Ahmad Shakir +6 位作者 Maqbool Ahmad Shahzada Khurram Muhammad Qaiser Saleem Muhammad Shafiq Jin-Ghoo Choi Habib Hamam Osama E.Sheta 《Intelligent Automation & Soft Computing》 2024年第4期765-781,共17页
Machine learning(ML)and data mining are used in various fields such as data analysis,prediction,image processing and especially in healthcare.Researchers in the past decade have focused on applying ML and data mining ... Machine learning(ML)and data mining are used in various fields such as data analysis,prediction,image processing and especially in healthcare.Researchers in the past decade have focused on applying ML and data mining to generate conclusions from historical data in order to improve healthcare systems by making predictions about the results.Using ML algorithms,researchers have developed applications for decision support,analyzed clinical aspects,extracted informative information from historical data,predicted the outcomes and categorized diseases which help physicians make better decisions.It is observed that there is a huge difference between women depending on the region and their social lives.Due to these differences,scholars have been encouraged to conduct studies at a local level in order to better understand those factors that affect maternal health and the expected child.In this study,the ensemble modeling technique is applied to classify birth outcomes based on either cesarean section(C-Section)or normal delivery.A voting ensemble model for the classification of a birth dataset was made by using a Random Forest(RF),Gradient Boosting Classifier,Extra Trees Classifier and Bagging Classifier as base learners.It is observed that the voting ensemble modal of proposed classifiers provides the best accuracy,i.e.,94.78%,as compared to the individual classifiers.ML algorithms are more accurate due to ensemble models,which reduce variance and classification errors.It is reported that when a suitable classification model has been developed for birth classification,decision support systems can be created to enable clinicians to gain in-depth insights into the patterns in the datasets.Developing such a system will not only allow health organizations to improve maternal health assessment processes,but also open doors for interdisciplinary research in two different fields in the region. 展开更多
关键词 Birth data classification ensemble model machine learning
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超市生鲜蔬菜供应链特征及损耗控制 被引量:7
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作者 谭锋 徐扬 +1 位作者 Brian Revell 卢澄 《食品工业科技》 CAS CSCD 北大核心 2010年第1期330-333,共4页
对目前超市生鲜蔬菜经营方式、供应途径及损耗原因的研究分析表明,超市蔬菜供应分为普通蔬菜供应链和无公害/有机蔬菜供应链两种模式。超市蔬菜的损耗主要分为由于生理、环境和微生物引起蔬菜新鲜度下降和腐烂变质所导致的自然损耗,以... 对目前超市生鲜蔬菜经营方式、供应途径及损耗原因的研究分析表明,超市蔬菜供应分为普通蔬菜供应链和无公害/有机蔬菜供应链两种模式。超市蔬菜的损耗主要分为由于生理、环境和微生物引起蔬菜新鲜度下降和腐烂变质所导致的自然损耗,以及由于员工操作和消费者挑选造成蔬菜损伤所导致的人为损耗,消费者挑选是人为损耗的主要原因。将食品科学与管理技术相结合,提出冷链保鲜和分类处理等措施可以降低自然损耗,有效的运营管理可以降低人为损耗。 展开更多
关键词 超市 蔬菜 供应链 损耗
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基于无人机和决策树算法的榆树疏林草原植被类型划分和覆盖度生长季动态估计 被引量:25
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作者 韩东 王浩舟 +1 位作者 郑邦友 王锋 《生态学报》 CAS CSCD 北大核心 2018年第18期6655-6663,共9页
植被覆盖度是评估生态环境质量与植被生长的重要指标,也是全球众多陆面过程模型和生态系统模型中表达植被动态的重要参数。卫星遥感和地面测量是估算植被覆盖度的常见方法。然而,如何精确估计榆树疏林草原上木本、草本不同类型植被的覆... 植被覆盖度是评估生态环境质量与植被生长的重要指标,也是全球众多陆面过程模型和生态系统模型中表达植被动态的重要参数。卫星遥感和地面测量是估算植被覆盖度的常见方法。然而,如何精确估计榆树疏林草原上木本、草本不同类型植被的覆盖度仍然具有挑战性。无人机飞行系统有效的补充了区域尺度低空间分辨率的卫星遥感影像与样地尺度实地调查之间的缺口,为精确的监测、评估疏林草原的植被动态提供了新途径。利用无人机监测平台和决策树算法构建了一套快速、准确、自动获取景观尺度植被类型和估算植被覆盖度的自动化工具,以浑善达克沙地榆树疏林草原为对象,应用无人机监测平台对榆树疏林草原长期定位监测大样地2017年生长季植被状况进行7次监测。结果表明:1)无人机植被监测平台数据飞行高度100 m,获取的样地数字正射影像空间分辨率为2.67 cm/像元,远高于高分卫星影像,利用决策树算法基于数字正射影像可以实现自动划分榆树疏林草原木本和草本植被类型和估算植被覆盖度; 2)生长季内榆树疏林草原木本植被覆盖度为(19±2)%,草本植被覆盖度为(50±8)%,植被总覆盖度为(69±9)%,相对于木本植被,草本植被生长季内盖度变幅较大; 3)在整个生长季中,木本植被和草本植被对植被总覆盖度的平均贡献率分别为27%和73%,草本植被对植被总盖度的贡献远大于木本植被,榆树疏林草原植被的盖度主要受草本植被的影响。本研究证明无人机监测平台是一种高效、准确的植被监测工具,结合机器学习算法,实现了景观尺度植被类型的自动划分和不同类型植被覆盖度快速获取;在浑善达克沙地榆树疏林草原地区首次获取了木本植被和草本植被覆盖度的生长季动态。该平台未来可应用于各种类型生态系统植被类型划分、监测和评估。 展开更多
关键词 浑善达克沙地 无人机监测平台 机器学习 正射影像 模式识别
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大面积3D有序介孔二氧化钛薄膜光子晶体制备与性能研究 被引量:9
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作者 胡行方 快素兰 +1 位作者 于云 Troung Vo-Van 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2005年第6期1463-1466,共4页
介绍了大面积有序反蛋白石结构介孔二氧化钛薄膜光子晶体制备与性能研究的进展.为了保证二氧化钛骨架结构的稳定性和有序度,从而使氧化钛介孔薄膜达到大面积结构均匀,在介孔薄膜制备过程中采用了几种新的工艺方法,其中包括二氧化硅晶体... 介绍了大面积有序反蛋白石结构介孔二氧化钛薄膜光子晶体制备与性能研究的进展.为了保证二氧化钛骨架结构的稳定性和有序度,从而使氧化钛介孔薄膜达到大面积结构均匀,在介孔薄膜制备过程中采用了几种新的工艺方法,其中包括二氧化硅晶体模板的应用和用NaOH溶液代替常用的HF溶液作为模板去除剂.制备的介孔二氧化钛薄膜光子晶体的面积达到厘米尺寸,二氧化钛骨架的填充率达到17.4%,薄膜制备过程中的收缩率<3%.薄膜透射光谱研究结果表明,这种大面积3D有序的反蛋白石结构介孔二氧化钛薄膜具有非常优良的光子带隙特性,有望成为一类具有非常好的发展和应用前景的光子晶体材料. 展开更多
关键词 3D有序结构 反蛋白石结构 二氧化钛薄膜光子晶体
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空间设计要素对建筑能耗的影响研究--以寒冷地区点式高层办公楼为例 被引量:3
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作者 刘立 吴迪 +2 位作者 李晓俊 刘丛红 菲利普·琼斯 《建筑节能》 CAS 2016年第9期59-65,共7页
以寒冷地区点式高层办公楼为研究对象,建立典型模型,利用能耗模拟软件Design Builder对空间设计参数与建筑能耗之间的关系进行模拟分析。模拟结果表明,空间设计中对建筑节能最有效的策略依次为:减少标准层的面积、适当降低层高和增加平... 以寒冷地区点式高层办公楼为研究对象,建立典型模型,利用能耗模拟软件Design Builder对空间设计参数与建筑能耗之间的关系进行模拟分析。模拟结果表明,空间设计中对建筑节能最有效的策略依次为:减少标准层的面积、适当降低层高和增加平面的长宽比。研究成果从节能的角度为建筑师最初的决策提供依据和借鉴。 展开更多
关键词 空间节能设计 建筑能耗模拟 寒冷地区 点式高层办公楼
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铕配合物与苯乙烯共聚物的研究(英文) 被引量:4
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作者 潘远凤 郑安呐 +2 位作者 XIAO Hui-ning 胡福增 蔡平雄 《功能材料》 EI CAS CSCD 北大核心 2005年第7期1119-1121,1125,共4页
将具有聚合活性的稀土铕有机配合物Eu3+(BA)2(AA)(phen)与苯乙烯共聚得到一种半透明且发光强度高的稀土高分子光致发光材料,通过凝胶色谱、红外光谱、紫外光谱对其结构进行表征,证实是共聚物,而不是共混掺杂。通过荧光光谱分析说明只要... 将具有聚合活性的稀土铕有机配合物Eu3+(BA)2(AA)(phen)与苯乙烯共聚得到一种半透明且发光强度高的稀土高分子光致发光材料,通过凝胶色谱、红外光谱、紫外光谱对其结构进行表征,证实是共聚物,而不是共混掺杂。通过荧光光谱分析说明只要引入少量的稀土配合物单体,共聚物就表现出配合物单体的强紫外吸收特性,并发射出Eu3+的特征荧光。热分析则表明共聚物引入稀土配合物基团后,其热稳定性得到了提高,而稀土配合物键合到大分子链后其结构单元热稳定性也得到相应的提高。 展开更多
关键词 EUROPIUM COMPLEXES RARE earth metal-containing polymer FLUORESCENCE
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喷雾机雾滴运行时间和沉降规律的试验 被引量:2
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作者 刘青 祁力钧 +2 位作者 傅泽田 王俊 Cooper S E 《农业机械学报》 EI CAS CSCD 北大核心 2007年第6期62-65,共4页
利用光电原理,采用湿度传感器和毫秒计设计了测量雾滴运行时间的试验方案,并测量了4种常见喷嘴在不同机器前进速度和喷雾压力下的雾滴运行时间。结果表明,在喷雾机正常工作状态下,由于雾锥角的存在,雾滴总是超前于喷杆到达目标物上,这... 利用光电原理,采用湿度传感器和毫秒计设计了测量雾滴运行时间的试验方案,并测量了4种常见喷嘴在不同机器前进速度和喷雾压力下的雾滴运行时间。结果表明,在喷雾机正常工作状态下,由于雾锥角的存在,雾滴总是超前于喷杆到达目标物上,这个时间上的提前量可以为变量喷雾系统的响应时间作必要的时间补偿。并通过采用三因素三水平的正交试验和方差分析,说明了喷嘴类型对雾滴运行时间的影响极为显著,而机器前进速度对雾滴运行时间的影响在5%的水平上显著。利用荧光跟踪试验,研究了3种喷嘴的不同时刻的沉降规律,从雾滴沉降的角度揭示了空心锥喷嘴存在很大的漂移性。 展开更多
关键词 喷雾机 雾滴 漂移 运行时间 沉降
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中国葡萄酒市场与供应链分析 被引量:1
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作者 徐扬 谭锋 +1 位作者 卢澄 Martin HINGLEY 《食品科学》 EI CAS CSCD 北大核心 2011年第S02期93-96,共4页
通过调查研究日前中国葡萄酒市场特点、国产酒与进口酒的竞争关系,以及葡萄酒市场供应链的状况,分析供应链成员的构成和选择标准,葡萄酒市场营销渠道;针对目前市场状况指出葡萄洒市场主要存在的问题,包括消费者认知、供应链成员之间的... 通过调查研究日前中国葡萄酒市场特点、国产酒与进口酒的竞争关系,以及葡萄酒市场供应链的状况,分析供应链成员的构成和选择标准,葡萄酒市场营销渠道;针对目前市场状况指出葡萄洒市场主要存在的问题,包括消费者认知、供应链成员之间的关系、关系营销以及进口酒的关税、品牌知名度的矛盾等,在此基础上,对中国葡萄酒市场提出建议和市场展望. 展开更多
关键词 葡萄酒市场 葡萄涌供应链 进口葡萄酒 关系营销
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马铃薯A病毒研究进展 被引量:1
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作者 张维 胡新喜 +2 位作者 熊兴耀 聂先舟 何长征 《中国马铃薯》 2013年第2期100-105,共6页
马铃薯A病毒(PotatovirusA,PVA)是马铃薯生产上危害较严重的病毒之一。PVA已知的寄主为茄科植物,在马铃薯上引起的症状与气候条件、马铃薯品种和PVA的株系有关。PVA基因组与其他PVY属已知序列的病毒核苷酸序列同源性在53%~58%之... 马铃薯A病毒(PotatovirusA,PVA)是马铃薯生产上危害较严重的病毒之一。PVA已知的寄主为茄科植物,在马铃薯上引起的症状与气候条件、马铃薯品种和PVA的株系有关。PVA基因组与其他PVY属已知序列的病毒核苷酸序列同源性在53%~58%之间,编码的11种蛋白在基因组复制、蛋白加工、蚜虫传毒、系统移动以及与寄主组分互作等方面具有各自的功能。马铃薯对PVA的抗性分为过敏抗性(HR)和极端抗性(ER)两类,植物对PVA的抗性机制主要分为显性基因介导的抗性、隐性基因介导的抗性、RNA介导的抗性。PVA的致病机理、PVA抗性基因挖掘和抗PVA转基因新策略将是今后的研究重点。 展开更多
关键词 PVA 致病症状 基因组 抗性
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血管内皮细胞生长因子在足细胞内的分布及表达多种亚型的研究
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作者 邢昌赢 Mathieson PW 《南京医科大学学报(自然科学版)》 CAS CSCD 北大核心 2001年第6期481-483,F002,共4页
目的 :探讨血管内皮细胞生长因子 ( VEGF)在足细胞内的分布及其所表达的 VEGF亚型。方法 :应用免疫荧光法观察 VEGF在足细胞内的分布 ;逆转录 PCR( RT- PCR)检测足细胞表达不同分子质量 VEGF的 m RNA和免疫蛋白印迹检测 VEGF蛋白等。结... 目的 :探讨血管内皮细胞生长因子 ( VEGF)在足细胞内的分布及其所表达的 VEGF亚型。方法 :应用免疫荧光法观察 VEGF在足细胞内的分布 ;逆转录 PCR( RT- PCR)检测足细胞表达不同分子质量 VEGF的 m RNA和免疫蛋白印迹检测 VEGF蛋白等。结果 :VEGF在足细胞内以细胞核为中心向胞质呈放射状分布 ,体外培养的足细胞可以表达 VEGF1 2 1 、VEGF1 6 5和 VEGF1 89,前两者表达较多 ,蛋白产物主要以 VEGF1 6 5为主。结论 :该研究首次发现足细胞在体外培养的条件下表达 VEGF,并且在细胞内分布具有一定的规律性 ,为进一步研究 VEGF在自身细胞和肾脏病中的作用提供了可靠的实验方法。 展开更多
关键词 足细胞 血管内皮细胞生长因子 分布 亚型 VEGF 肾疾病 糖蛋白
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