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Polypore funga and species diversity in tropical forest ecosystems of Africa,America and Asia,and a comparison with temperate and boreal regions of the Northern Hemisphere 被引量:1
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作者 Heng Zhao Yingda Wu +4 位作者 Zhirong Yang Honggao Liu Fang Wu Yucheng Dai Yuan Yuan 《Forest Ecosystems》 SCIE CSCD 2024年第4期391-400,共10页
Polypores play a cru cial role in energy recycling and forest regeneration in forest ecosystems.The majority of them are wood degraders;some are forest pathogens and others are ectomycorrhizal symbionts.The basidiocar... Polypores play a cru cial role in energy recycling and forest regeneration in forest ecosystems.The majority of them are wood degraders;some are forest pathogens and others are ectomycorrhizal symbionts.The basidiocarps provide food and shelter for many organisms,mostly invertebrates,but also some vertebrates,as well as food and medicine for humans.Despite extensive research on the species diversity and phylogenetic relationships of polypores in recent years,there remains a lack of comprehensive understanding of their distribution patterns and species composition at the large scale.Checklists of polypores from the tropical zone,including tropical Africa,tropical America,and tropical Asia,were analyzed for species diversity,distribution patterns,major taxa,and nutritional modes.A total of 1,902 polypore species was found in the three regions,representing 8 orders,46families,and 250 genera of Agaricomycetes.The orders Polyporales(especially the family Polyporaceae)and Hymenochaetales(especially the family Hymenochaetaceae)had the most prolific taxa,with their species accounting for 93.4%of the total polypores listed.Each of 1,565(or 82.3%)of the total 1,902 species were found in only one of the three regions studied,and we treat them temporarily as"regional endemic species".Only 141species were shared among all three regions,accounting for a mere 7.4%.Tropical Africa and tropical America had the greatest number of shared species and the highest S?rensen similarity index(SC)value.Tropical forests had a higher species richness compared with temperate to boreal forests of the Northern Hemisphere,and in addition,also a higher proportion of white rot polypores compared to brown rot and ectomycorrhizal species.This study outlines the distribution patterns and species diversity of polypores in the world,shedding light on their ecological significance in diverse ecosystems. 展开更多
关键词 AGARICOMYCETES MACRofUNGI Species composition Wood-decay fungi
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Influence of ear tags on the results of body composition analysis in mice
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作者 He Liu Yinghua Zhang +4 位作者 Peng Zhang Weiping Teng Zhongyan Shan Yushu Li Dan Wang 《Animal Models and Experimental Medicine》 CAS CSCD 2024年第4期578-583,共6页
Background:The aim of this study was to investigate the influence of marking meth-ods on the outcomes of body composition analysis and provide guidance for the se-lection of marking methods in mouse body composition a... Background:The aim of this study was to investigate the influence of marking meth-ods on the outcomes of body composition analysis and provide guidance for the se-lection of marking methods in mouse body composition analysis.Methods:Male C57BL/6J mice aged 6 weeks were randomly assigned for pre-and post-ear tagging measurements.The body composition of the mice was measured using a small animal body composition analyzer,which provided measurements of the mass of fat,lean,and free fluid.Then,the mass of fat,lean and free fluid to body weight ratio was gained.Further data analysis was conducted to obtain the range and coeffi-cient of variation in body composition measurements for each mouse.The distribution of fat and lean tissue in the mice was also analyzed by comparing the fat-to-lean ratio.Results:(1)The mass of all body composition components in the ear tagging group was significantly lower than that in the control group.(2)There was a significant in-crease in the range and coefficient of variation of body composition measurements between the ear tagging group and the control group.(3)The fat-to-lean ratio in the ear tagging group was significantly lower than that in the control group.Conclusions:Ear tagging significantly lowered the results of body composition analy-sis in mice and higher the results of measurement error.Therefore,ear tagging should be avoided as much as possible when conducting body composition analysis experi-ments in mice. 展开更多
关键词 body composition analysis ear tagging labeling method stainless steel toe clipping
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Investigation of the effect of hydrocarbons and monoesters in the gelators’composition on the properties of edible oleogel
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作者 Yuliya Frolova Roman Sobolev +1 位作者 Varuzhan Sarkisyan Alla Kochetkova 《Grain & Oil Science and Technology》 CAS 2024年第2期96-104,共9页
Natural wax gelators have different compositions of compounds(hydrocarbons,wax esters,free fatty alcohols,and free fatty acids),which results in oleogels with varying properties.To maintain a consistent composition,th... Natural wax gelators have different compositions of compounds(hydrocarbons,wax esters,free fatty alcohols,and free fatty acids),which results in oleogels with varying properties.To maintain a consistent composition,the individual components can be added to the original wax gelator.The content of hydrocarbons and wax esters greatly affects the structuring process of liquid edible oils with waxes.The aim of this study was to evaluate the possibility of modifying the properties of beeswax as a gelling agent by adding hydrocarbons or monoesters to obtain oleogels with specific properties.Various tests were conducted to assess the changes in the oleogel properties,such as color,microstructure,oil-binding capacity,thermal and textural properties.The research results have shown that the addition of the studied fractions has led to a significant change in all properties of oleogels.The initial size of oleogel crystals(7.29±1.80μm)changed after adding fractions,varying from 5.28μm to 12.58μm with hydrocarbons and from 9.95μm to 30.41μm with wax esters.The addition of 30%–50% hydrocarbons decreased the ability of the oleogels to bind oil and made them less firm compared to samples with 10%-20% hydrocarbons.Adding 10%-20% monoesters increased the firmness of the oleogels,but this indicator decreased when their content was increased to 50%.The obtained data indicate that hydrocarbons and wax esters can be used for targeted correction of the gelling properties of beeswax. 展开更多
关键词 Oleogel BEESWAX Hydrocarbons Wax monoesters Component composition of gelator Textural properties FOOD
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Automated body composition analysis system based on chest CT for evaluating content of muscle and adipose
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作者 YANG Jie LIU Yanli +2 位作者 CHEN Xiaoyan CHEN Tianle LIU Qi 《中国医学影像技术》 CSCD 北大核心 2024年第8期1242-1248,共7页
Objective To establish a body composition analysis system based on chest CT,and to observe its value for evaluating content of chest muscle and adipose.Methods T7—T8 layer CT images of 108 pneumonia patients were col... Objective To establish a body composition analysis system based on chest CT,and to observe its value for evaluating content of chest muscle and adipose.Methods T7—T8 layer CT images of 108 pneumonia patients were collected(segmented dataset),and chest CT data of 984 patients were screened from the COVID 19-CT dataset(10 cases were randomly selected as whole test dataset,the remaining 974 cases were selected as layer selection dataset).T7—T8 layer was classified based on convolutional neural network(CNN)derived networks,including ResNet,ResNeXt,MobileNet,ShuffleNet,DenseNet,EfficientNet and ConvNeXt,then the accuracy,precision,recall and specificity were used to evaluate the performance of layer selection dataset.The skeletal muscle(SM),subcutaneous adipose tissue(SAT),intermuscular adipose tissue(IMAT)and visceral adipose tissue(VAT)were segmented using classical fully CNN(FCN)derived network,including FCN,SegNet,UNet,Attention UNet,UNET++,nnUNet,UNeXt and CMUNeXt,then Dice similarity coefficient(DSC),intersection over union(IoU)and 95 Hausdorff distance(HD)were used to evaluate the performance of segmented dataset.The automatic body composition analysis system was constructed based on optimal layer selection network and segmentation network,the mean absolute error(MAE),root mean squared error(RMSE)and standard deviation(SD)of MAE were used to evaluate the performance of automatic system for testing the whole test dataset.Results The accuracy,precision,recall and specificity of DenseNet network for automatically classifying T7—T8 layer from chest CT images was 95.06%,84.83%,92.27%and 95.78%,respectively,which were all higher than those of the other layer selection networks.In segmentation of SM,SAT,IMAT and overall,DSC and IoU of UNet++network were all higher,while 95HD of UNet++network were all lower than those of the other segmentation networks.Using DenseNet as the layer selection network and UNet++as the segmentation network,MAE of the automatic body composition analysis system for predicting SM,SAT,IMAT,VAT and MAE was 27.09,6.95,6.65 and 3.35 cm 2,respectively.Conclusion The body composition analysis system based on chest CT could be used to assess content of chest muscle and adipose.Among them,the UNet++network had better segmentation performance in adipose tissue than SM. 展开更多
关键词 body composition THORAX muscle skeletal adipose tissue deep learning tomography X-ray computed
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Longitudinal changes in body weight of breastfeeding mothers in the first year after delivery and its relationship with human milk composition:a combined longitudinal and cross-sectional cohort study
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作者 Huijuan Ruan Yajie Zhang +6 位作者 Qingya Tang Xuan Zhao Xuelin Zhao Yi Xiang Wei Geng Yi Feng Wei Cai 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期254-264,共11页
Objective:Postpartum weight retention(PPWR)is a common problem among women after childbirth.The main objectives of this study are to understand the changes in body weight of breastfeeding mothers during long-term foll... Objective:Postpartum weight retention(PPWR)is a common problem among women after childbirth.The main objectives of this study are to understand the changes in body weight of breastfeeding mothers during long-term follow-up and preliminarily explore the relationship between maternal body weight and human milk composition,including macronutrients,leptin,and adiponectin.Methods:The study included a longitudinal cohort(122 mothers),and a cross-sectional cohort(37 mothers).The human milk,maternal weight,and dietary surveys were collected in the longitudinal cohort at different follow-up time points(1-14 days postpartum,2-4 months postpartum,5-7 months postpartum,and 12-17 months postpartum).The maternal body weight was analyzed using the responses in the survey questionnaires.A milk analyzer based on the mid-infrared spectroscopy(MIRS)was used to determine milk composition,and nutrition analysis software evaluated dietary intakes.In the cross-sectional cohort,participating mothers were asked to provide blood and human milk samples and pertinent information related to maternal body composition.Maternal body composition was measured by bioelectrical impedance analysis(BIA),while ELISA analyzed leptin and adiponectin in milk and serum.Results:At 5-7 months postpartum,the PPWR of breastfeeding mothers was(2.46±3.59)kg.At 12-17 months postpartum,the PPWR was(0.98±4.06)kg.PPWR was found to be negatively correlated with milk fat content within 14 days postpartum and positively correlated at 2-4 months postpartum.In addition,the maternal weight and body muscle mass were positively correlated with leptin and adiponectin in milk.Plasma leptin was positively correlated with the mother’s body weight,body mass index(BMI),FAT percentage,and body fat mass,while plasma adiponectin did not correlate with any parameter.The results also indicate that the PPWR did not correlate with leptin and adiponectin in plasma or milk.Conclusions:Breastfeeding mothers may retain considerable weight gain one year after delivery.Human milk composition may be related to changes in maternal body weight.Leptin and adiponectin in breast milk and leptin in plasma are associated with the maternal body composition.This study supports the notion that maternal nutritional status may affect offspring health through lactation,and future research should focus on exploring weight management of postpartum mothers. 展开更多
关键词 Human milk Milk composition Body weight Body mass index(BMI) Weight gain Postpartum weight retention
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Total Fat, Fatty Acid Composition, Tocopherol and Tocotrienol Profiles in Fermented Beans of Ten Controlled Pollinated Cocoa (Theobroma cacao L.) Hybrids from Cameroon
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作者 Martin Paul Arnaud Mbida Simon Perrez Akoa +3 位作者 Ronelle Fabiola Mbia Manga Ndjaga Jude Martine Louise Ondobo Onomo Pierre Effa 《American Journal of Plant Sciences》 CAS 2024年第5期359-373,共15页
This study aimed to discriminate ten Cameroonian cocoa hybrids according to their total fat, fatty acid composition, tocopherol and tocotrienol profiles. Six cocoa clones from the gene banks of the Cameroon Cocoa Deve... This study aimed to discriminate ten Cameroonian cocoa hybrids according to their total fat, fatty acid composition, tocopherol and tocotrienol profiles. Six cocoa clones from the gene banks of the Cameroon Cocoa Development Corporation were used to create hybrids. The determination of fatty acid composition was carried out by using a gas chromatography (GC) apparatus coupled by a flame ion detector (FID). Tocopherol and tocotrienol analysis was performed by upper high-performance liquid chromatography (UHPLC). Information on the impact of the genotype on the cocoa fat composition was provided. The major fatty acids (FA) in fermented samples are stearic (34.57%), palmitic (26.13%), oleic (34.13%) and linoleic (3.16%) acids. (35.05% to 35.6%). SCA12 × ICS40, SCA12 × SNK13, SNK13 × T79/501 have the least hard cocoa butters. Tocopherols analysis showed a predominance of γ-tocopherols (94.64 ± 1.51 to 292.16 ± 3.17 µg∙g<sup>−1</sup>), whereas only a small amount of β and δ-tocopherol (from 0.46 to 2.78 µg∙g<sup>−1</sup> and 0.12 to 5.82 respectively) was observed. No γ-tocotrienol was found in fermented samples. A differentiation in terms of total fat and tocopherol content was observed amongst hybrids with the same mother-clone, suggesting an impact of pollen on these compounds. 展开更多
关键词 Cocoa Hybrids Lipid composition UHPLC GC-FID
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Effect of Composite Composition on the Contact Angle of B_(4)C-xTiB_(2)/Cu
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作者 HU Dong ZHANG Xin +1 位作者 ZHANG Jinyong LEI Liwen 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第5期1116-1120,共5页
The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this work.The results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with th... The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this work.The results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with the composition rate of TiB_(2)or B_(4)C while the temperature is in the range of 1300 to 1350℃,consistent with the expectation of the commonly used theoretical method.However,a nonlinear relationship between the contact angle and the composition rate unexpectedly occurred at temperatures ranging from 1400 to 1500℃.The big difference of the contact angles between the molten metal and the components in the composites was found to be the key point.This result identifies that the commonly used theoretical method only works at a limited difference of the contact angle of the liquid on the different phases in the composites,and fails at a big difference. 展开更多
关键词 WETTING B_(4)C-TiB_(2) composites interfacial reaction
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Investigation on Effect of Composition on the Drying of Castables with Cement Binder
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作者 Bruno TOUZO Hirotaka GOTO +2 位作者 Uwe KLIPPEL Josh SAYRE Jeff BOGAN 《China's Refractories》 CAS 2024年第3期30-36,共7页
Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable ... Monolithic refractory castables comprising a hydraulic bond are still used in a vast majority of cases because of their flexibility and robustness,despite many developments for chemical as well as non-cement castable binders.The drying can however be a challenge,in particular for deflocculated dense castables of the low cement castable range.Many publications have been released on this topic for the last ten years,but they often focused on the drying mechanisms or on the addition of drying aids.This paper presents some experimental results on the effect of the composition on the drying properties,especially on the effect of silicon carbide,used for its high thermal conductivity,and on the matrix system.It also introduces two laboratory tests to study and iteratively improve the drying schedule of a given castable lining.The results show that the spalling resistance and the vapor pressure build-up are significantly influenced by the formulation.It is also shown that the castable properties after drying can be altered if the heating rate is very high. 展开更多
关键词 DRYING aggregate composition binding system heating rate
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The Role of Body Composition Analyzer in the Preoperative Assessment of Breast Cancer Patients
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作者 Lijuan Zhang Qiaoling Zhong +6 位作者 Yun Ding Jinlan Li Qinghua Luo Liping Zhang Yuezhou Guo Na Li Huizhen Zhang 《Journal of Cancer Therapy》 2024年第9期320-329,共10页
Background: The segmental multi-frequency bioelectrical impedance analysis (SMF-BIA) is a useful method for evaluating physical health and nutritional status in various clinical settings. But less is known about its r... Background: The segmental multi-frequency bioelectrical impedance analysis (SMF-BIA) is a useful method for evaluating physical health and nutritional status in various clinical settings. But less is known about its role in the preoperative assessment of breast cancer patients. Herein, we try to monitor the changes in body composition of preoperative patients by SMF-BIA and figure out its association with clinical features. Methods: The changes in body composition were monitored by SMF-BIA in 563 female patients with breast cancer. Monitor body moisture and collect relevant data on the day before surgery as a prospective study. Retrospective analysis will be conducted based on preoperative data and pathological results after lymph node resection, Spearman’s correlation coefficients were calculated to investigate the correlation among parameters. Results: We found that the body water, extracellular water ratio, and bioelectrical impedance of the affected upper limbs of patients with different tumor stages or different numbers of lymph node metastases were significantly different from those of their healthy upper limbs (P P P P P Conclusion: SMF-BIA can help monitor the changes in body composition of breast cancer patients and provide detailed information for making a personalized treatment plan and individual nursing schedule. However, the value of SMF-BIA in preoperative assessment still needs to be validated in large prospective clinical trials. 展开更多
关键词 Breast Cancer Body composition Tumor Stages Lymphatic Metastasis Multi-Frequency Bioelectrical Impedance Analysis
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Determination of the Mineral Composition of the Pulp and Evaluation of the Acute Toxicity of the Seeds of Carica papaya L. Consumed in Lubumbashi and Kinshasa in the Democratic Republic of the Congo
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作者 Guelord Inkalaba Janvier Arnauld Kiza +8 位作者 Magain Mihatano Mathilde Bushiri Furaha Arthur Duki Olivier Nzingula Armelle Naniwambote Maguy Luvandu Nicole Misengabu Désiré Musuyu Fridolin Kodondi Kule-Koto 《Journal of Biosciences and Medicines》 2024年第9期266-279,共14页
This work aimed, on the one hand, to determine the mineral and phytochemical composition of Carica papaya in order to guarantee the food safety of consumers and on the other hand, to evaluate the acute toxicity of pap... This work aimed, on the one hand, to determine the mineral and phytochemical composition of Carica papaya in order to guarantee the food safety of consumers and on the other hand, to evaluate the acute toxicity of papaya seeds. The papayas were bought at the Mzée market in Lubumbashi and Selembao in Kinshasa. Fruit sampling was done according to the ISO 7002 standard on agricultural and food products;the papayas were firm, mature, and without stains or physical damage. The analysis results of the papaya pulp showed both for the samples from the city of Lubumbashi and for the city province of Kinshasa that it contains respectively 85.87% and 84.46% water, 0.59% and 0.53% ash content. The mineral evaluation of our two samples presented a potassium content of 200 ± 8 mg, magnesium 13.12 ± 3 mg, calcium 22.15 ± 2 mg, sodium 3 mg ± 0.5 for the sample from Lubumbashi and 192.32 ± 8 mg of potassium, 14.458 ± 3 mg of magnesium, 20.58 ± 2 mg of calcium and 3.58 ± 0.5 mg of sodium for the sample from Kinshasa in macroelements. Concerning the trace elements, after analysis, we found zinc content (0.29 ± 0.1 mg and 0.12 ± 0.1 mg), copper (0.02 ± 0.01 mg and 0.14 ± 0.01 mg), and iron (2.22 ± 0.5 mg and 2.04 ± 0.5 mg) respectively for Lubumbashi and Kinshasa. The chemical screening indicates the presence of alkaloids, saponosides, tannins catechics, flavonoids and anthocyanins in the palm wine and ethanolic extract of the seeds of Carica papaya and an absence of cyanogenic glycosides and gallic tannins. With mild toxicity, the seeds of the fruit of Carica papaya L. can be used with moderate risk by the population. 展开更多
关键词 Carica papaya Mineral composition Acute Toxicity
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Chemical composition and pharmacological activities of the Phellodendron chinense Schneid
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作者 Yi′an Shi Yunpeng Yang +3 位作者 Wenhan Wang Yibo Wan Yao Zhao Yu Chen 《Asian Journal of Traditional Medicines》 2024年第5期285-298,共14页
Phellodendron chinense Schneid(P.chinense),as a traditional Chinese medicine,is commonly used in clinical practice.It has the effects of drying dampness,clearing heat,detoxifying,purging fire,and reducing swelling.Its... Phellodendron chinense Schneid(P.chinense),as a traditional Chinese medicine,is commonly used in clinical practice.It has the effects of drying dampness,clearing heat,detoxifying,purging fire,and reducing swelling.Its main chemical components are flavonoids and alkaloids,which have various pharmacological effects such as lowering blood sugar,lowering blood pressure and immunosuppression.With the continuous development of modern science and technology,the research on P.chinense Schneid has increased.This study reviews the chemical components and pharmacological effects of P.chinense Schneid,and provides reference for its further research and development. 展开更多
关键词 Phellodendron chinense Schneid chemical composition pharmacological activity
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A Discussion on the Structure and Spatial Composition of Long Museum West Bund
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作者 Guanyan Xiao 《Journal of World Architecture》 2024年第3期1-8,共8页
The Long Museum,with its distinctive T-shaped“umbrella-vault”structure,offers a rich array of spatial experiences.This article delves into space from both structural and compositional perspectives.As the constructio... The Long Museum,with its distinctive T-shaped“umbrella-vault”structure,offers a rich array of spatial experiences.This article delves into space from both structural and compositional perspectives.As the construction mediator,the umbrella vault embodies the consistency of construction and implies the causality of the surface.Presented as an element,the space flows freely,showing diverse fields and order.In terms of the liberation of its meaning,the space offers static perception and dynamic experience,creating a rich exhibition atmosphere.As a distinct entity,the umbrella-vault presents the physical nature,and the dialogue between the Long Museum and the city makes it a museum of art for the people. 展开更多
关键词 Long Museum STRUCTURE Spatial composition Umbrella-vault
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A Study on the Correlation Between LIWC Word Categories and Chinese Composition Writing Performance of Fourth,Fifth,and Sixth Grade Students
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作者 Yufeng Wu 《Journal of Contemporary Educational Research》 2024年第1期199-206,共8页
This study focuses on the analysis of the Chinese composition writing performance of fourth,fifth,and sixth grade students in 16 selected schools in Longhua District,Shenzhen during the spring semester of 2023.Using L... This study focuses on the analysis of the Chinese composition writing performance of fourth,fifth,and sixth grade students in 16 selected schools in Longhua District,Shenzhen during the spring semester of 2023.Using LIWC(Linguistic Inquiry and Word Count)as a text analysis tool,the study explores the impact of LIWC categories on writing performance which is scaled by score.The results show that the simple LIWC word categories have a significant positive influence on the composition scores of lower-grade students;while complex LIWC word categories have a significant negative influence on the composition scores of lower-grade students but a significant positive influence on the composition scores of higher-grade students.Process word categories have a positive influence on the composition scores of all three grades,but the impact of complex process word categories increases as the grade level rises. 展开更多
关键词 Chinese composition LIWC word categories Writing performance Grades Text mining
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Study on the Influence of AI Composition Software on Students'Creative Ability in Music Education
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作者 Shuang Zhang Xiaofeng Lu Xinwen Liu 《教育技术与创新》 2024年第2期1-17,共17页
Generative AI technology for human-assisted tools has made great strides in recent years,and studying the impact of this technology on students'compositional abilities plays an important role in promoting changes ... Generative AI technology for human-assisted tools has made great strides in recent years,and studying the impact of this technology on students'compositional abilities plays an important role in promoting changes in music education.Previous studies have focused on the performance of music composition software itself in terms of composition,with less consideration given to the impact of creators'compositional ability after using assistive composition tools.Thus,this paper designs a controlled experiment to investigate the changes in students'compositional ability before and after using AI composition tools.This paper finds that students'compositional abilities in all areas of composition improved to varying degrees after using AI composition tools.This paper compares the differences in compositional abilities of students with and without the education of AI composition tools,which has practical implications for vigorously promoting the adoption of AI composition tools in university music education teaching. 展开更多
关键词 Music Education AI composition composition Ability Assessment
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Study of the Chemical and Mineralogical Composition of Kindia Bauxite in the Republic of Guinea: The Case of the Saföfö Site
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作者 Mouctar Camara Mamadouba Aboubacar Fofana +4 位作者 Mohamed Dubréka Sylla Alpha Madiou Diallo Aboubacar Diallo Aly Hawa Camara Sékou Traore 《Journal of Materials Science and Chemical Engineering》 2024年第10期62-71,共10页
The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and m... The chemical and mineralogical composition of bauxite deposits is a key factor in the profitability of refining processes. The study of bauxites from the Saföfö site has assessed variations in chemical and mineralogical composition under various conditions, as well as the optimum conditions for their exploitation. The methodologies used in this study include experimental methods for determining moisture content, chemical composition, mineralogical composition, and specific density of bauxite. The results show significant variation in moisture content among the bauxite samples, with values ranging from 2.90% to 17.80%. The silica percentages in the samples range from 1.69% to 8.14%, while alumina percentages vary from 36.81% to 54.03%. After calcination, alumina oxide percentages range from 40% to 75%. After chemical activation, alumina oxides Al2O3 range from 40% to over 50%. Gibbsite is the most abundant mineral, accounting for about 60% - 70% of the total composition of the bauxite samples. Samples A to F have bulk densities varying between approximately 3.6 and 3.9. Sample B has the highest density, around 3.9, while sample C has the lowest, at around 3.5. Bauxite mining at the Saföfö site offers significant potential for the alumina industry, provided appropriate processing methods are selected to maximize quality and profitability while minimizing environmental impact. 展开更多
关键词 BAUXITE Chemical composition GUINEA Mineralogy and Saföfö
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The Effect of Mineral Composition and Quantity of Fines on the Atterberg Limits and Compaction Characteristics of Soils
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作者 Abdalhamid Musbah Muad Mohammed Adem Alfghia 《Open Journal of Civil Engineering》 2024年第2期258-276,共19页
Because of the various elements that come into play in natural soil formation, the impact of varied proportions of mineral composition and fines amount on Atterberg limits and compaction characteristics of soils is no... Because of the various elements that come into play in natural soil formation, the impact of varied proportions of mineral composition and fines amount on Atterberg limits and compaction characteristics of soils is not well known. Three distinct soil samples were used in this investigation. The findings indicated the effect of varied mineral composition proportions and fines amount on the liquid limit, plastic limit, and plasticity index as assessed by the Casagrande test and hand-rolling method. The fluctuation of maximum dry density and optimal moisture content with these three soils has also been studied. Furthermore, correlations were established to indicate the compaction parameters and the amount of minerals and particles in the soil. The data show that the mineral content of the soil has a direct impact on the Atterberg limits and compaction characteristics. Soils containing larger percentages of expansive minerals, such as montmorillonite, have more flexibility and volume change capability. Mineral composition influences compaction parameters such as maximum dry density, ideal water content, axial strain, and axial stress. Soils with a larger proportion of fines, such as Soil 2 and Soil 3, have stronger flexibility and lower compaction qualities, with higher ideal water content and lower maximum dry density. Soil 1 has moderate flexibility and intermediate compaction qualities due to its low fines percentage. The effect of different mineral compositions and fines on the Atterberg limits and compaction characteristics of soils can be used to predict the behavior of compacted soils encountered in engineering practices, reducing the time and effort required to assess soil suitability for engineering use. 展开更多
关键词 Atterberg Limit Mineral composition Quantity of Fines Maximum Dry Unit Weight Optimum Water Content
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Optimization of the Gas Generator in Composite Power System with Tip-Jet Rotor
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作者 Jianxiang Tang Yifei Wu +1 位作者 Yun Wang Jinwu Wu 《Journal of Power and Energy Engineering》 2024年第3期60-74,共15页
The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of th... The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment. 展开更多
关键词 Tip-Jet Driven Rotor Composite Power system Gas Generator Optimization Hydrogen Peroxide Aerodynamic Characteristics Numerical Simulation
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A Study of EM Algorithm as an Imputation Method: A Model-Based Simulation Study with Application to a Synthetic Compositional Data
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作者 Yisa Adeniyi Abolade Yichuan Zhao 《Open Journal of Modelling and Simulation》 2024年第2期33-42,共10页
Compositional data, such as relative information, is a crucial aspect of machine learning and other related fields. It is typically recorded as closed data or sums to a constant, like 100%. The statistical linear mode... Compositional data, such as relative information, is a crucial aspect of machine learning and other related fields. It is typically recorded as closed data or sums to a constant, like 100%. The statistical linear model is the most used technique for identifying hidden relationships between underlying random variables of interest. However, data quality is a significant challenge in machine learning, especially when missing data is present. The linear regression model is a commonly used statistical modeling technique used in various applications to find relationships between variables of interest. When estimating linear regression parameters which are useful for things like future prediction and partial effects analysis of independent variables, maximum likelihood estimation (MLE) is the method of choice. However, many datasets contain missing observations, which can lead to costly and time-consuming data recovery. To address this issue, the expectation-maximization (EM) algorithm has been suggested as a solution for situations including missing data. The EM algorithm repeatedly finds the best estimates of parameters in statistical models that depend on variables or data that have not been observed. This is called maximum likelihood or maximum a posteriori (MAP). Using the present estimate as input, the expectation (E) step constructs a log-likelihood function. Finding the parameters that maximize the anticipated log-likelihood, as determined in the E step, is the job of the maximization (M) phase. This study looked at how well the EM algorithm worked on a made-up compositional dataset with missing observations. It used both the robust least square version and ordinary least square regression techniques. The efficacy of the EM algorithm was compared with two alternative imputation techniques, k-Nearest Neighbor (k-NN) and mean imputation (), in terms of Aitchison distances and covariance. 展开更多
关键词 compositional Data Linear Regression Model Least Square Method Robust Least Square Method Synthetic Data Aitchison Distance Maximum Likelihood Estimation Expectation-Maximization Algorithm k-Nearest Neighbor and Mean imputation
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The Influence of Plant Diversity and Functional Composition on Ecosystem Stability of Four Stipa Communities in the Inner Mongolia Plateau 被引量:65
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作者 白永飞 李凌浩 +1 位作者 黄建辉 陈佐忠 《Acta Botanica Sinica》 CSCD 2001年第3期280-287,共8页
The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner M... The main purpose of this study was to examine the effects of plant species diversity and functional composition (the identity of the plant functional groups) on ecosystem stability of Stipa, communities in the Inner Mongolia Plateau. The research work was based on a 12-year study (from 1984 to 1995) of species abundance, diversity, and primary productivity of four Stipa communities, i.e. S. baicalensis Roshev., S. grandis P. Smirn., S, krylovii Roshev., and S. klemenzii Roshev. respectively. The Shnnon-Wiener index was used as a measurement of plant diversity, while functional composition was used to differentiate the functional groups that were included in the communities. The plant species of four Stipa communities were classified into functional groups based on the differences in life forms and ecological groups, which influence their performance in resource requirements, seasonality of growth, tolerance to water stress, and life history. Plant species were classified into five functional groups based on their differences in life form, shrubs and half shrubs, perennial bunch grasses, perennial rhizome grasses, forbs, annuals and biennials. Based on their differences in water requirement these species were classified into four functional groups: xerads, intermediate xerads, intermediate mesophytes, and mesophytes. The results showed: 1) Plant species diversity stabilized ecosystem processes. Shannon-Wiener index were 2.401 4, 2.172 0, 1.624 8, 0.354 3 from S. baicalensis community to S. grandis, S. krylovii and S. klemenzii community, respectively. The dynamics of the aboveground net primary productivity (ANPP) for a 12-year's period showed a reverse pattern, the coefficients of variation of the four communities were 21.94%, 20.63%, 29.21% and 39.72% respectively. 2) The Life form functional group component of diversity was a greater determinant of the ecosystem processes than the species component of diversity. The effects of perennial bunch grasses, perennial rhizome grasses and forbs on community stability were highly significant. 3) The ecological group component of diversity was also a great determinant of the ecosystem processes. The effects of xerads, intermediate xerads, and mesophytes on community stability were also very strong. 展开更多
关键词 Inner Mongolia Plateau Stipa communities the aboveground net primary productivity species diversity functional composition
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Compositional and Hollow Engineering of Silicon Carbide/Carbon Microspheres as High-Performance Microwave Absorbing Materials with Good Environmental Tolerance 被引量:2
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作者 Lixue Gai Yahui Wang +5 位作者 Pan Wan Shuping Yu Yongzheng Chen Xijiang Han Ping Xu Yunchen Du 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第9期128-146,共19页
Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable M... Microwave absorbing materials(MAMs)characterized by high absorption efficiency and good environmental tolerance are highly desirable in practical applications.Both silicon carbide and carbon are considered as stable MAMs under some rigorous conditions,while their composites still fail to produce satisfactory microwave absorption performance regardless of the improvements as compared with the individuals.Herein,we have successfully implemented compositional and structural engineering to fabricate hollow Si C/C microspheres with controllable composition.The simultaneous modulation on dielectric properties and impedance matching can be easily achieved as the change in the composition of these composites.The formation of hollow structure not only favors lightweight feature,but also generates considerable contribution to microwave attenuation capacity.With the synergistic effect of composition and structure,the optimized SiC/C composite exhibits excellent performance,whose the strongest reflection loss intensity and broadest effective absorption reach-60.8 dB and 5.1 GHz,respectively,and its microwave absorption properties are actually superior to those of most SiC/C composites in previous studies.In addition,the stability tests of microwave absorption capacity after exposure to harsh conditions and Radar Cross Section simulation data demonstrate that hollow SiC/C microspheres from compositional and structural optimization have a bright prospect in practical applications. 展开更多
关键词 SiC/C composites compositional engineering Hollow engineering Microwave absorption Environmental tolerance
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