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Multi-View Picture Fuzzy Clustering:A Novel Method for Partitioning Multi-View Relational Data 被引量:1
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作者 Pham Huy Thong Hoang Thi Canh +2 位作者 Luong Thi Hong Lan Nguyen Tuan Huy Nguyen Long Giang 《Computers, Materials & Continua》 2025年第6期5461-5485,共25页
Multi-view clustering is a critical research area in computer science aimed at effectively extracting meaningful patterns from complex,high-dimensional data that single-view methods cannot capture.Traditional fuzzy cl... Multi-view clustering is a critical research area in computer science aimed at effectively extracting meaningful patterns from complex,high-dimensional data that single-view methods cannot capture.Traditional fuzzy clustering techniques,such as Fuzzy C-Means(FCM),face significant challenges in handling uncertainty and the dependencies between different views.To overcome these limitations,we introduce a new multi-view fuzzy clustering approach that integrates picture fuzzy sets with a dual-anchor graph method for multi-view data,aiming to enhance clustering accuracy and robustness,termed Multi-view Picture Fuzzy Clustering(MPFC).In particular,the picture fuzzy set theory extends the capability to represent uncertainty by modeling three membership levels:membership degrees,neutral degrees,and refusal degrees.This allows for a more flexible representation of uncertain and conflicting data than traditional fuzzy models.Meanwhile,dual-anchor graphs exploit the similarity relationships between data points and integrate information across views.This combination improves stability,scalability,and robustness when handling noisy and heterogeneous data.Experimental results on several benchmark datasets demonstrate significant improvements in clustering accuracy and efficiency,outperforming traditional methods.Specifically,the MPFC algorithm demonstrates outstanding clustering performance on a variety of datasets,attaining a Purity(PUR)score of 0.6440 and an Accuracy(ACC)score of 0.6213 for the 3 Sources dataset,underscoring its robustness and efficiency.The proposed approach significantly contributes to fields such as pattern recognition,multi-view relational data analysis,and large-scale clustering problems.Future work will focus on extending the method for semi-supervised multi-view clustering,aiming to enhance adaptability,scalability,and performance in real-world applications. 展开更多
关键词 Multi-view clustering picture fuzzy sets dual anchor graph fuzzy clustering multi-view relational data
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Construction of a Marketing System for Leveled Mathematics Readers from a User-Oriented Perspective: A Strategy Optimization Study Based on the 4V Marketing Model
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作者 Zhaoyong Ouyang Guanlin Liu 《Proceedings of Business and Economic Studies》 2025年第5期39-44,共6页
In the context of the continuous deepening of the“Double Reduction”policy and the growing demand for quality education,leveled mathematics readers,as an emerging form of publishing that integrates subject education ... In the context of the continuous deepening of the“Double Reduction”policy and the growing demand for quality education,leveled mathematics readers,as an emerging form of publishing that integrates subject education and reading experience,face challenges such as unclear leveling logic,insufficient functional support,and weak user engagement.This paper introduces the 4V marketing theory and constructs an analytical framework from four dimensions:differentiation,functionality,added value,and resonance.Two representative products,“Climbing Mathematics”and“Spark Mathematics,”are selected for a typical case comparison to identify their strengths and weaknesses in content design,service systems,and brand operation,and to extract transferable strategic elements.The study finds that the user-value-oriented strategy based on the 4V model can effectively address the core issues in the market promotion and user relationship building of leveled mathematics readers,providing practical paths and theoretical support for educational publishing institutions to achieve product innovation and brand upgrading in this niche field. 展开更多
关键词 4V marketing theory Leveled mathematics readers Educational publishing Typical case analysis Marketing strategy
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Correlation between human embryo morphokinetics and pregnancy outcomes on Asian infertility women:A retrospective cohort study
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作者 Hop Vu Dinh Cuong An Manh +3 位作者 Anh Phi Thi Tu Huong Nguyen Thi Lien Hoang Le Hanh Nguyen Van 《Asian pacific Journal of Reproduction》 2025年第3期140-142,共3页
Selecting the embryo with the highest implantation potential is a top priority in in-vitro fertilization(IVF)centers.Few studies have explored the relationship between day 5 blastocyst morphokinetics and implantation ... Selecting the embryo with the highest implantation potential is a top priority in in-vitro fertilization(IVF)centers.Few studies have explored the relationship between day 5 blastocyst morphokinetics and implantation outcomes[1].Despite numerous time-lapse studies,the findings often conflict due to differences in patient demographics,lab conditions,and protocols,such as oxygen concentration[2].Thus,there is ongoing debate regarding which parameters are most predictive of implantation. 展开更多
关键词 vitro fertilization BLASTOCYST lab conditions time lapse studies human embryo morphokinetics implantation potential Asian infertility women pregnancy outcomes
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Robust Real-Time Analysis of Cow Behaviors Using Accelerometer Sensors and Decision Trees with Short Data Windows and Misalignment Compensation
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作者 Duc-Nghia Tran Viet-Manh Do +1 位作者 Manh-Tuyen Vi Duc-Tan Tran 《Computers, Materials & Continua》 2025年第5期2525-2553,共29页
This study focuses on the design and validation of a behavior classification system for cattle using behavioral data collected through accelerometer sensors.Data collection and behavioral analysis are achieved using m... This study focuses on the design and validation of a behavior classification system for cattle using behavioral data collected through accelerometer sensors.Data collection and behavioral analysis are achieved using machine learning(ML)algorithms through accelerometer sensors.However,behavioral analysis poses challenges due to the complexity of cow activities.The task becomes more challenging in a real-time behavioral analysis system with the requirement for shorter data windows and energy constraints.Shorter windows may lack sufficient information,reducing algorithm performance.Additionally,the sensor’s position on the cowsmay shift during practical use,altering the collected accelerometer data.This study addresses these challenges by employing a 3-s data window to analyze cow behaviors,specifically Feeding,Lying,Standing,and Walking.Data synchronization between accelerometer sensors placed on the neck and leg compensates for the lack of information in short data windows.Features such as the Vector of Dynamic Body Acceleration(VeDBA),Mean,Variance,and Kurtosis are utilized alongside the Decision Tree(DT)algorithm to address energy efficiency and ensure computational effectiveness.This study also evaluates the impact of sensor misalignment on behavior classification.Simulated datasets with varying levels of sensor misalignment were created,and the system’s classification accuracy exceeded 0.95 for the four behaviors across all datasets(including original and simulated misalignment datasets).Sensitivity(Sen)and PPV for all datasets were above 0.9.The study provides farmers and the dairy industry with a practical,energy-efficient system for continuously monitoring cattle behavior to enhance herd productivity while reducing labor costs. 展开更多
关键词 Monitoring behavior classification ACCELEROMETER sensor MISALIGNMENT leg-mounted neck-mounted COW
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CGB-Net:A Novel Convolutional Gated Bidirectional Network for Enhanced Sleep Posture Classification
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作者 Hoang-Dieu Vu Duc-Nghia Tran +2 位作者 Quang-TuPham Ngoc-Linh Nguyen Duc-Tan Tran 《Computers, Materials & Continua》 2025年第11期2819-2835,共17页
This study presents CGB-Net,a novel deep learning architecture specifically developed for classifying twelve distinct sleep positions using a single abdominal accelerometer,with direct applicability to gastroesophagea... This study presents CGB-Net,a novel deep learning architecture specifically developed for classifying twelve distinct sleep positions using a single abdominal accelerometer,with direct applicability to gastroesophageal reflux disease(GERD)monitoring.Unlike conventional approaches limited to four basic postures,CGB-Net enables fine-grained classification of twelve clinically relevant sleep positions,providing enhanced resolution for personalized health assessment.The architecture introduces a unique integration of three complementary components:1D Convolutional Neural Networks(1D-CNN)for efficient local spatial feature extraction,Gated Recurrent Units(GRU)to capture short-termtemporal dependencieswith reduced computational complexity,and Bidirectional Long Short-Term Memory(Bi-LSTM)networks for modeling long-term temporal context in both forward and backward directions.This complementary integration allows the model to better represent dynamic and contextual information inherent in the sensor data,surpassing the performance of simpler or previously published hybrid models.Experiments were conducted on a benchmark dataset consisting of 18 volunteers(age range:19–24 years,mean 20.56±1.1 years;height 164.78±8.18 cm;weight 55.39±8.30 kg;BMI 20.24±2.04),monitored via a single abdominal accelerometer.A subjectindependent evaluation protocol with multiple random splits was employed to ensure robustness and generalizability.The proposed model achieves an average Accuracy of 87.60% and F1-score of 83.38%,both reported with standard deviations over multiple runs,outperforming several baseline and state-of-the-art methods.By releasing the dataset publicly and detailing themodel design,this work aims to facilitate reproducibility and advance research in sleep posture classification for clinical applications. 展开更多
关键词 Sleep posture classification deep learning accelerometer gastroesophageal reflux disease(GERD) CGB-Net convolutional neural networks recurrent neural networks human activity recognition
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Relationship between gastric mucosal atrophy by endoscopy and non-ampullary duodenal epithelial tumors
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作者 Kazuya Ohno Eiji Nakatani +10 位作者 Takafumi Kurokami Asami Kawai Ryosuke Itai Masanori Matsuda Yuichi Masui Tatsunori Satoh Shinya Ikeda Taiyo Hirata Shodai Takeda Makoto Suzuki Ken Haruma 《World Journal of Gastrointestinal Oncology》 2025年第2期84-92,共9页
BACKGROUND The pathogenesis of non-ampullary duodenal epithelial tumors(NADETs)is not fully understood.NADETs that express gastric-type mucin phenotypes(GNADETs)are noteworthy because of their high malignancy.Gastric ... BACKGROUND The pathogenesis of non-ampullary duodenal epithelial tumors(NADETs)is not fully understood.NADETs that express gastric-type mucin phenotypes(GNADETs)are noteworthy because of their high malignancy.Gastric foveolar metaplasia,from which G-NADETs originate,protects the duodenal mucosa from gastric acidity.As gastric acid secretion is affected by endoscopic gastric mucosal atrophy(EGMA),we hypothesized that EGMA would be associated with GNADETs.AIM To evaluate the association between EGMA and the occurrence of G-NADETs.METHODS This cross-sectional retrospective study investigated the relationship between EGMA and NADETs in 134 patients.The duodenum was divided into parts 1(bulb),2(superior duodenal angle to the papilla),and 3(anal side of the papilla to the horizontal part).The effects of gastric acidity and presence of Brunner’s glands were considered.EGMA was divided into types C(no or mild atrophy)and O(severe atrophy).Mucin phenotype expressions in NADETs were divided into gastric,intestinal,gastrointestinal,and unclassifiable.RESULTS When NADETs were classified according to EGMA,105 were classified as type C and 29 as type O.G-NADETs were present in 11.9%(16 cases)of all cases,and all 16 cases were of type C.Among G-NADETs,93.8%(15 cases)were present in part 1 or 2.There was an association between G-NADETs and type C in part 1,and 50.0%(eight of 16 cases)of G-NADETs were associated with a current or previous Helicobacter pylori infection status.Additionally,all eight cases occurred in part 1.CONCLUSION G-NADETs were significantly associated with type C.Gastric acidity and Brunner's gland growth may be associated with G-NADETs. 展开更多
关键词 Gastric acidity Gastric foveolar metaplasia Gastric mucosal atrophy Helicobacter pylori Mucin phenotype Nonampullary duodenal epithelial tumor
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An Innovative Semi-Supervised Fuzzy Clustering Technique Using Cluster Boundaries
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作者 Duong Tien Dung Ha Hai Nam +1 位作者 Nguyen Long Giang Luong Thi Hong Lan 《Computers, Materials & Continua》 2025年第12期5341-5357,共17页
Active semi-supervised fuzzy clustering integrates fuzzy clustering techniques with limited labeled data,guided by active learning,to enhance classification accuracy,particularly in complex and ambiguous datasets.Alth... Active semi-supervised fuzzy clustering integrates fuzzy clustering techniques with limited labeled data,guided by active learning,to enhance classification accuracy,particularly in complex and ambiguous datasets.Although several active semi-supervised fuzzy clustering methods have been developed previously,they typically face significant limitations,including high computational complexity,sensitivity to initial cluster centroids,and difficulties in accurately managing boundary clusters where data points often overlap among multiple clusters.This study introduces a novel Active Semi-Supervised Fuzzy Clustering algorithm specifically designed to identify,analyze,and correct misclassified boundary elements.By strategically utilizing labeled data through active learning,our method improves the robustness and precision of cluster boundary assignments.Extensive experimental evaluations conducted on three types of datasets—including benchmark UCI datasets,synthetic data with controlled boundary overlap,and satellite imagery—demonstrate that our proposed approach achieves superior performance in terms of clustering accuracy and robustness compared to existing active semi-supervised fuzzy clustering methods.The results confirm the effectiveness and practicality of our method in handling real-world scenarios where precise cluster boundaries are critical. 展开更多
关键词 Clustering algorithms semi-supervised classification active learning fuzzy clustering boundary elements boundary identification boundary correction
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Unraveling the Morphological and Energetic Properties of 2PACz Self-Assembled Monolayers Fabricated With Upscaling Deposition Methods
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作者 Silvia Mariotti Ilhem Nadia Rabehi +13 位作者 Congyang Zhang Xiaomin Huo Jiahao Zhang Penghui Ji Tianhao Wu Tongtong Li Shuai Yuan Xiaomin Liu Ting Guo Chenfeng Ding Hengyuan Wang Annalisa Bruno Luis K.Ono Yabing Qi 《Energy & Environmental Materials》 2025年第2期291-304,共14页
Self-assembled monolayers(SAMs)are widely used as hole transport materials in inverted perovskite solar cells,offering low parasitic absorption and suitability for semitransparent and tandem solar cells.While SAMs hav... Self-assembled monolayers(SAMs)are widely used as hole transport materials in inverted perovskite solar cells,offering low parasitic absorption and suitability for semitransparent and tandem solar cells.While SAMs have shown to be promising in small-area devices(≤1 cm^(2)),their application in larger areas has been limited by a lack of knowledge regarding alternative deposition methods beyond the common spin-coating approach.Here,we compare spin-coating and upscalable methods such as thermal evaporation and spray-coating for[2-(9H-carbazol-9-yl)ethyl]phosphonic acid(2PACz),one of the most common carbazole-based SAMs.The impact of these deposition methods on the device performance is investigated,revealing that the spray-coating technique yields higher device performance.Furthermore,our work provides guidelines for the deposition of SAM materials for the fabrication of perovskite solar modules.In addition,we provide an extensive characterization of 2PACz films focusing on thermal evaporation and spray-coating methods,which allow for thicker 2PACz deposition.It is found that the optimal 2PACz deposition conditions corresponding to the highest device performances do not always correlate with the monolayer characteristics. 展开更多
关键词 2PACz EVAPORATION Perovskite solar cells Self-assembled monolayer Spray-coating
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Hidden Biodiversity in the Tropical Rain Forests:Two New Species of Leptobrachella Smith 1925 (Anura:Megophryidae) from Vietnam
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作者 Van Chung HOANG The Cuong PHAM +4 位作者 Quang Tien PHAN Trong Dang DO Bin WANG Jianping JIANG Quang Truong NGUYEN 《Asian Herpetological Research》 2025年第2期169-191,共23页
Two new species of Leptobrachella are described from Vietnam based on morphological differences and genetic divergences in 16S rRNA mitochondrial gene sequences.The new taxa are distinguished from each other and from ... Two new species of Leptobrachella are described from Vietnam based on morphological differences and genetic divergences in 16S rRNA mitochondrial gene sequences.The new taxa are distinguished from each other and from other species of the genus Leptobrachella in body size,head width/length ratio,tympanum morphology,dorsal skin texture,the presence/absence of fringes on toes,color of dorsal and ventral body,and iris color.The two new species are also divergent from each other and from other congeners by a 4.14% or greater uncorrected genetic distance.Leptobrachella batxatensis sp.nov.is genetically closest to L.shiwandashanensis and L.wuhuangmontis from China.Leptobrachella duyenae sp.nov.is genetically closest to L.bidoupensis from Vietnam with strong nodal support from both BI and ML analyses(1.0/99%). 展开更多
关键词 16S rRNA mitochondrial gene Leptobrachella batxatensis sp.nov. Leptobrachella duyenae sp.nov. morphology taxonomy
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An Active Safe Semi-Supervised Fuzzy Clustering with Pairwise Constraints Based on Cluster Boundary
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作者 Duong Tien Dung Ha Hai Nam +1 位作者 Nguyen Long Giang Luong Thi Hong Lan 《Computers, Materials & Continua》 2025年第12期5625-5642,共18页
Semi-supervised clustering techniques attempt to improve clustering accuracy by utilizing a limited number of labeled data for guidance.This method effectively integrates prior knowledge using pre-labeled data.While s... Semi-supervised clustering techniques attempt to improve clustering accuracy by utilizing a limited number of labeled data for guidance.This method effectively integrates prior knowledge using pre-labeled data.While semi-supervised fuzzy clustering(SSFC)methods leverage limited labeled data to enhance accuracy,they remain highly susceptible to inappropriate or mislabeled prior knowledge,especially in noisy or overlapping datasets where cluster boundaries are ambiguous.To enhance the effectiveness of clustering algorithms,it is essential to leverage labeled data while ensuring the safety of the previous knowledge.Existing solutions,such as the Trusted Safe Semi-Supervised Fuzzy Clustering Method(TS3FCM),struggle with random centroid initialization,fixed neighbor radius formulas,and handling outliers or noise at cluster overlaps.A new framework called Active Safe Semi-Supervised Fuzzy Clustering with Pairwise Constraints Based on Cluster Boundary(AS3FCPC)is proposed in this paper to deal with these problems.It does this by combining pairwise constraints and active learning.AS3FCPC uses active learning to query only the most informative data instances close to the cluster boundaries.It also uses pairwise constraints to enforce the cluster structure,which makes the system more accurate and robust.Extensive test results on diverse datasets,including challenging noisy and overlapping scenarios,demonstrate that AS3FCPC consistently achieves superior performance compared to state-of-the-art methods like TS3FCM and other baselines,especially when the data is noisy and overlaps.This significant improvement underscores AS3FCPC’s potential for reliable and accurate semisupervised fuzzy clustering in complex,real-world applications,particularly by effectively managing mislabeled data and ambiguous cluster boundaries. 展开更多
关键词 Active learning safe semi-supervised fuzzy clustering confidence weight boundary identification pairwise constraints
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Laser stealth dicing ofβ-Ga_(2)O_(3):Theoretical and experimental studies
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作者 Zhanpeng Sun Junjie Zou +8 位作者 Rui Li Zhaofu Zhang Junqi Mai Zijun Qi David Vazquez Cortes Qijun Wang Gai Wu Wei Shen Sheng Liu 《Journal of Materials Science & Technology》 2025年第35期303-312,共10页
Gallium oxide(Ga_(2)O_(3))is an ultra-wide bandgap semiconductor with excellent potential for high-power and ultraviolet optoelectronic device applications.High-performance Ga_(2)O_(3)-based high-power devices rely he... Gallium oxide(Ga_(2)O_(3))is an ultra-wide bandgap semiconductor with excellent potential for high-power and ultraviolet optoelectronic device applications.High-performance Ga_(2)O_(3)-based high-power devices rely heavily on precise processing,especially in wafer dicing.Laser stealth dicing(LSD)is an innova-tive laser technology that utilizes a focused laser to create subsurface modifications in the wafer without surface damage.LSD has broad application prospects in the field of semiconductor precision processing.In this work,the idea of achieving high-quality dicing ofβ-Ga_(2)O_(3) wafers via LSD was proposed.A com-bination of atomistic simulations and experiments was used to understand the underlying mechanism of LSD ofβ-Ga_(2)O_(3) wafers.On the one hand,the laser loading and fracture process ofβ-Ga_(2)O_(3) wafers were simulated using molecular dynamics(MD)methods as well as a machine learning potential.The effects of single-pulse energy on LSD were analyzed through the lattice residual pressure,the final total energy of the system,the internal atomic strain,and the maximum stress value during uniaxial tension.On the other hand,based on the MD simulations,LSD was successfully performed onβ-Ga_(2)O_(3) wafers along three main crystal planes in the laboratory,resulting in good surface quality.This work not only provides profound optimization strategies for the LSD process ofβ-Ga_(2)O_(3),establishing the foundation for high-quality dicing ofβ-Ga_(2)O_(3) wafers,but also verifies the accuracy of MD simulations in predict-ing trends related to the LSD,offering a potential approach for high-quality dicing of other materials in future research. 展开更多
关键词 β-Ga_(2)O_(3) Laser stealth dicing High-quality wafer dicing Molecular dynamics Machine learning potential
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A Hybrid Deep Learning Method for Forecasting Reservoir Water Level from Sentinel-2 Satellite Images
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作者 Hoang Thi Minh Chau Tran Thi Ngan +2 位作者 Nguyen Long Giang Tran Manh Tuan Tran Kim Chau 《Computers, Materials & Continua》 2025年第6期4915-4937,共23页
Global climate change,along with the rapid increase of the population,has put significant pressure on water security.A water reservoir is an effective solution for adjusting and ensuring water supply.In particular,the... Global climate change,along with the rapid increase of the population,has put significant pressure on water security.A water reservoir is an effective solution for adjusting and ensuring water supply.In particular,the reservoir water level is an essential physical indicator for the reservoirs.Forecasting the reservoir water level effectively assists the managers in making decisions and plans related to reservoir management policies.In recent years,deep learning models have been widely applied to solve forecasting problems.In this study,we propose a novel hybrid deep learning model namely the YOLOv9_ConvLSTM that integrates YOLOv9,ConvLSTM,and linear interpolation to predict reservoir water levels.It utilizes data from Sentinel-2 satellite images,generated from visible spectrum bands(Red-Blue-Green)to reconstruct true-color reservoir images.Adam is used as the optimization algorithm with the loss function being MSE(Mean Squared Error)to evaluate the model’s error during training.We implemented and validated the proposed model using Sentinel-2 satellite imagery for the An Khe reservoir in Vietnam.To assess its performance,we also conducted comparative experiments with other related models,including SegNet_ConvLSTM and UNet_ConvLSTM,on the same dataset.The model performances were validated using k-fold cross-validation and ANOVA analysis.The experimental results demonstrate that the YOLOv9_ConvLSTM model outperforms the compared models.It has been seen that the proposed approach serves as a valuable tool for reservoir water level forecasting using satellite imagery that contributes to effective water resource management. 展开更多
关键词 YOLOv9 ConvLSTM reservoir water level forecasting satellite images
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Rediscovery and Revision of the Diagnostic Characters of Opisthotropis daovantieni Orlov, Darevsky, and Murphy, 1998(Squamata:Natricidae)from Southern Vietnam, with Notes on its Hemipenial Morphology and Defensive Behavior
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作者 Zongyuan GAO Yong ZHANG +4 位作者 Vu Dang Hoang NGUYEN Ke JIANG Tao Thien NGUYEN Jiatang LI Jinlong REN 《Asian Herpetological Research》 2025年第1期49-65,共17页
The Tien's Mountain Stream Snake,Opisthotropis daovantieni Orlov, Darevsky, and Murphy, 1998, has been represented solely by its type series, with no additional specimens reported in the past two decades. As a res... The Tien's Mountain Stream Snake,Opisthotropis daovantieni Orlov, Darevsky, and Murphy, 1998, has been represented solely by its type series, with no additional specimens reported in the past two decades. As a result, limited data exist and O. daovantieni remains one of the least studied members of its genus. Based on a re-examination of the type series, analysis of newly collected topotypic specimens, and a review of museum collections, this study provides an updated and comprehensive morphological characterization of O. daovantieni including detailed descriptions of hemipenial morphology, revised diagnostic characters,phylogenetic positioning, and ecological insights.Based on morphological comparisons with congeners, we also define the informal Opisthotropis spenceri group to facilitate future taxonomic work. In addition, this study documents a previously unreported defensive behavior involving tail-poking,observed in the field and thus far unique within the genus Opisthotropis. 展开更多
关键词 diagnostic characters HEMIPENIS Opisthotropis spenceri group sulcus spermaticus tail-poking behavior
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Direct Observation of Early-Stage Polymer Crystallization Driven by Surface Wrinkling and Compressive Stress in Thin Films
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作者 Peng Zhang Stephan V.Roth +1 位作者 Peter Muller-Buschbaum Tian-Bai He 《Chinese Journal of Polymer Science》 2025年第2期360-367,共8页
The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surfa... The early stages of crystallization and occurrence of surface wrinkling were investigated using poly(butadiene)-block-poly(ε-caprolactone)with an ordered lamellar structure.Direct evidence has demonstrated that surface wrinkling precedes nucleation and crystal growth.This study examined the relationship between surface wrinkling,nucleation,and the formation of crystalline supramolecular structures using atomic force microscopy(AFM)and X-ray scattering measurements.Surface wrinkling is attributed to curving induced by accumulated stresses,including residual stress from the sample preparation and thermal stress during cooling.These stresses cause large-scale material flow and corresponding changes in the molecular conformations,potentially reducing the nucleation barrier.This hypothesis is supported by the rapid crystal growth observed following the spread of surface wrinkles.Additionally,the surface curving of the polymer thin film creates local minima of the free energy,facilitating nucleation.The nuclei subsequently grow into crystalline supramolecular structures by incorporating polymer molecules from the melt.This mechanism highlights the role of localized structural inhomogeneity in the early stages of crystallization and provides new insights into structure formation processes. 展开更多
关键词 Polymer crystallization NUCLEATION Surface wrinkling Stress Thin film
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Probing Solar Polar Regions
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作者 DENG Yuanyong TIAN Hui +45 位作者 JIANG Jie YANG Shuhong LI Hao CAMERON Robert GIZON Laurent HARRA Louise WIMMER-SCHWEINGRUBER Robert F AUCHÈRE Frédéric BAI Xianyong BELLOT RUBIO Luis CHEN Linjie CHEN Pengfei CHITTA Lakshmi Pradeep DAVIES Jackie FAVATA Fabio FENG Li FENG Xueshang GAN Weiqun HASSLER Don HE Jiansen HOU Junfeng HOU Zhenyong JIN Chunlan LI Wenya LIN Jiaben NANDY Dibyendu PANT Vaibhav ROMOLI Marco SAKAO Taro KRISHNA PRASAD Sayamanthula SHEN Fang SU Yang TORIUMI Shin TRIPATHI Durgesh WANG Linghua WANG Jingjing XIA Lidong XIONG Ming YAN Yihua YANG Liping YANG Shangbin ZHANG Mei ZHOU Guiping ZHU Xiaoshuai WANG Jingxiu WANG Chi 《空间科学学报》 北大核心 2025年第4期913-942,共30页
The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind,ultimately being vital in controlling sola... The magnetic fields and dynamical processes in the solar polar regions play a crucial role in the solar magnetic cycle and in supplying mass and energy to the fast solar wind,ultimately being vital in controlling solar activities and driving space weather.Despite numerous efforts to explore these regions,to date no imaging observations of the Sun's poles have been achieved from vantage points out of the ecliptic plane,leaving their behavior and evolution poorly understood.This observation gap has left three top-level scientific questions unanswered:How does the solar dynamo work and drive the solar magnetic cycle?What drives the fast solar wind?How do space weather processes globally originate from the Sun and propagate throughout the solar system?The Solar Polarorbit Observatory(SPO)mission,a solar polar exploration spacecraft,is proposed to address these three unanswered scientific questions by imaging the Sun's poles from high heliolatitudes.In order to achieve its scientific goals,SPO will carry six remote-sensing and four in-situ instruments to measure the vector magnetic fields and Doppler velocity fields in the photosphere,to observe the Sun in the extreme ultraviolet,X-ray,and radio wavelengths,to image the corona and the heliosphere up to 45 R_(s),and to perform in-situ detection of magnetic fields,and low-and high-energy particles in the solar wind.The SPO mission is capable of providing critical vector magnetic fields and Doppler velocities of the polar regions to advance our understanding of the origin of the solar magnetic cycle,providing unprecedented imaging observations of the solar poles alongside in-situ measurements of charged particles and magnetic fields from high heliolatitudes to unveil the mass and energy supply that drive the fast solar wind,and providing observational constraints for improving our ability to model and predict the three-dimensional(3D)structures and propagation of space weather events. 展开更多
关键词 SUN Space exploration Solar magnetic cycle Solar wind Space weather
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水文循环模拟中蒸散发估算方法综述 被引量:43
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作者 赵玲玲 夏军 +3 位作者 许崇育 王中根 苏磊 龙藏瑞 《地理学报》 EI CSCD 北大核心 2013年第1期127-136,共10页
为选取基于水文循环估算蒸散发方法提供依据,首先对常用水文模型中蒸散发估算方法进行回顾,根据其物理机理的强弱性,将水文模型中蒸散估算方法分为整体折算法和分类汇总法。当前水文模型中整体折算法占较大比重,它们之间的差异有两点:... 为选取基于水文循环估算蒸散发方法提供依据,首先对常用水文模型中蒸散发估算方法进行回顾,根据其物理机理的强弱性,将水文模型中蒸散估算方法分为整体折算法和分类汇总法。当前水文模型中整体折算法占较大比重,它们之间的差异有两点:一是潜在蒸散发估算方法不同;二是土壤干燥度折算函数不同;研究表明:由于水文模型存在不确定性及Penman-Monteith方法具有较高资料要求,致使模拟中使用该方法与使用其它简化经验公式相似或更差的水文循环模拟效果。所以对于不同水文模型,如何选取与之复杂程度相兼容的潜在蒸散发估算方程和土壤干燥度折算函数来降低模型的不确定性需进一步讨论。在此基础上,预估基于水文循环估算蒸散发方法朝着复杂机理化和简单实用化两个方向发展。 展开更多
关键词 水文模型 流域蒸散发 潜在蒸散发 土壤可用水函数
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蒙元时期陕甘宁交界地区干湿变化特征 被引量:5
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作者 戴君虎 葛全胜 +3 位作者 肖树芳 王梦麦 吴文祥 崔海亭 《地理学报》 EI CSCD 北大核心 2009年第7期839-849,共11页
从官修正史、方志和历朝纪事本末、区域气象灾害年鉴等历史文献资料中提取关于陕甘宁交界地区(元前期陕西四川行省的西北部以及元后期的陕西行省和甘肃行省的交界地区,主要包括宁夏府路、河州路、巩昌路、奉元路和延安路之间的部分)的... 从官修正史、方志和历朝纪事本末、区域气象灾害年鉴等历史文献资料中提取关于陕甘宁交界地区(元前期陕西四川行省的西北部以及元后期的陕西行省和甘肃行省的交界地区,主要包括宁夏府路、河州路、巩昌路、奉元路和延安路之间的部分)的水涝、干旱等气候信息共240余条,利用湿润指数法、旱涝灾害定级法对其干湿变化特点进行研究。研究发现1208-1369年期间,陕甘宁交界地区气候总体以干旱为主。旱涝灾害发生频率的比例为85/38。按照旱涝变化类型可将研究区旱涝变化过程分为三个时段,1208-1240年是以干旱为主要特征,局部时段偶发水涝灾害的时期;1240-1320年,基本持续干旱,而且极端干旱事件频发;1320-1369年,旱灾略有好转,但是旱涝交并发生。蒙元时期陕甘宁交界地区的干湿变化具有明显的转折性和周期性。转折主要发生在1230年和1325年前后,以此两点为界,前后气候变化类型有比较明显的差异。蒙元时期的干湿变化具有10年和23年的准周期,均与太阳活动周期吻合,说明蒙元时期区域干湿变化受太阳活动影响较大。 展开更多
关键词 干湿变化 陕甘宁交界地区 历史气候 元朝
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资源型城市财源建设的风险识别与制度优化路径--以陕西省延安市为例 被引量:8
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作者 宋敏 刘学敏 Hal T.Nelson 《中国软科学》 CSSCI 北大核心 2016年第10期62-70,共9页
1994年财税体制改革促成了此后延续至今的改革红利,但其财政分权的改革远未到位,近年来能源富集区经济发展中遇到的地方税收体系建设滞后、地方政府财政困难、提供基本公共服务能力弱等问题均与此密切相关。今后所实施新一轮改革中,财... 1994年财税体制改革促成了此后延续至今的改革红利,但其财政分权的改革远未到位,近年来能源富集区经济发展中遇到的地方税收体系建设滞后、地方政府财政困难、提供基本公共服务能力弱等问题均与此密切相关。今后所实施新一轮改革中,财税体制改革是全面深化经济体制改革的核心之一,应重点解决资源富集区矿产资源开发收益没有得到合理分配对地方政府财源建设所带来的风险。本文以陕西省延安市为例,认真分析财源结构、三次产业税收收入、税收收入与非税收收入的状况,以及省市分税的影响,深入研究现行财政分权影响地方财源建设的四大风险:税收与税源分离的风险、三次产业税源结构调整的风险、财政收支缺口的风险和税制改革滞后所引发的潜在风险,并深入剖析问题根源,积极探索优化资源型城市财源建设的制度路径。 展开更多
关键词 财政分权 资源型城市 风险识别 制度优化
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银岛膜表面胸腺嘧啶吸附行为的表面增强拉曼光谱和表面增强红外光谱研究 被引量:2
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作者 郭浩 毕立恒 +1 位作者 丁丽 莫育俊 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2011年第12期3273-3276,共4页
利用激光刻蚀法制备了具有"化学纯净"表面的银岛膜,该岛膜有很好的表面增强特性。利用表面增强拉曼光谱和表面增强红外光谱对胸腺嘧啶分子在银岛膜表面的吸附状态进行了对比研究。表面增强拉曼光谱中CN和C—O伸缩振动模式... 利用激光刻蚀法制备了具有"化学纯净"表面的银岛膜,该岛膜有很好的表面增强特性。利用表面增强拉曼光谱和表面增强红外光谱对胸腺嘧啶分子在银岛膜表面的吸附状态进行了对比研究。表面增强拉曼光谱中CN和C—O伸缩振动模式的出现表明胸腺嘧啶分子由原来的酮式结构变成了烯醇式结构;C(4)O伸缩振动谱带明显增强和N(3)的去质子化异构体特征峰的存在证明胸腺嘧啶分子是通过O(8)和N(3)的共同作用倾斜地吸附在银岛膜表面。对10-5 mol.L-1胸腺嘧啶在银岛膜表面上的红外光谱利用欧米采样器进行了反射法测量,发现其红外吸收增强了200倍。红外信号分析的结果支持了胸腺嘧啶分子通过O(8)与银表面发生相互作用的论断,同时也可得出胸腺嘧啶倾斜地吸附在银岛膜表面的结论。 展开更多
关键词 胸腺嘧啶 银岛膜 表面增强拉曼光谱 表面增强红外光谱
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基于ADL-ARCH模型的我国外汇干预目标之实证研究 被引量:2
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作者 李科 陈平 《中山大学学报(社会科学版)》 CSSCI 北大核心 2010年第5期202-208,共7页
以外汇干预操作中的冲销干预与非冲销干预理论为基础,基于计量经济学时间序列ADL和ARCH模型分别对我国外汇干预目标特征中的逆风向性、波动性和非对称性三大干预特征进行实证检验。通过对中国1996年1月到2009年8月间外汇干预数据进行实... 以外汇干预操作中的冲销干预与非冲销干预理论为基础,基于计量经济学时间序列ADL和ARCH模型分别对我国外汇干预目标特征中的逆风向性、波动性和非对称性三大干预特征进行实证检验。通过对中国1996年1月到2009年8月间外汇干预数据进行实证检验,发现我国外汇干预目标的逆风向性和非对称性因素显著,而波动性因素不明显。数据说明我国央行进行外汇干预的针对目标是汇率的变动而不是市场的波动幅度,并且对于升值贬值的干预幅度明显不同。与前人研究结论不同的是:汇率干预目标对于升值表现了较小程度的外汇干预,而对于贬值所表现的干预力度较大。另外,得出了外汇干预的长期持续性特点的实证结果,从而提出了外汇均衡目标的实现需要长期的货币政策配合调整等政策建议。 展开更多
关键词 汇率 外汇干预 ARCH 模型 ADL 模型
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