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Stable seasonal migration patterns in giant pandas

Zoological Research 2023年第2期44卷 341-348页

作者： Meng Wang Yong-Gang Nie Ronald R.Swaisgood Wei Wei Wen-Liang Zhou ze-jun zhang Gui-Ming Wang Fu-Wen Wei Key Laboratory of Animal Ecology and Conservation Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Giant Panda Research San Diego Zoo Institute for Conservation ResearchEscondidoCalifornia 92027USA Department of Wildlife Fisheries and AquacultureMississippi State UniversityMississippi 39762USA

A critical function of animal movement is to maximize access to essential resources in temporally fluctuating and spatially heterogeneous *** mediated resource fluctuations may influence animal movements,enabling them to track changing resource distributions,resulting in annual migration *** conservation-dependent giant panda(Ailuropoda melanoleuca) displays seasonal movement patterns;however,the key factor driving these seasonal migration patterns remains poorly ***,we used GPS tracking collars to monitor the movements of six giant pandas over a 12-year period across different elevations,and performed statistical analysis of seasonal migration directions,routes,habitat revisitation,home range overlap,first arrival events,and *** results revealed a compelling pattern of seasonal migrations that facilitated the ability of the pandas to forage at the appropriate time and place to maximize nutritional *** results indicated that pandas utilize spatial memory to locate reliable food resources,as evidenced by their annual return to the same or similar winter and summer home ranges and the consistently maintained percentage of home range *** novel insights into giant panda foraging and movement ecology not only enhance our understanding of its ability to adapt to nutritionally poor dietary resources but also provide important information for the development of resource utilization-based protection and management strategies.

关键词： Giant panda Seasonal migration Home range Foraging ecology Spatial memory

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Experimental study of reservoir damage of water-based fracturing fluids prepared by different polymers

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Petroleum Science 2024年第5期21卷 3298-3306页

作者： Guo-Dong Wu Li-Kun Wang Chun-Yan Zhao ze-jun zhang Jian-Yu Yin Maryamgul Anwaier Hong-Da Ren Dan Yang Shu-Li Yin Zhuo-Lin Cai Dao-Yi Zhu Engineering Technology Research Institute Xinjiang Oilfield CompanyKaramay834000XinjiangChina Luliang Oilfield Operation Area Xinjiang Oilfield CompanyKaramay834000XinjiangChina China University of Petroleum-Beijing at Karamay Karamay834000XinjiangChina

Fracturing operations can effectively improve the production of low-permeable reservoirs. The performance of fracturing fluids directly affects the fracturing efficiency and back flow capacity. As polymerbased fracturing fluids(such as guar gum(GG), polyacrylamide(HPAM), etc.) are high-viscosity fluids formed by viscosifiers and crosslinking agents, the degree of gel breakage after the fracturing operation directly influences the damage degree to the reservoir matrix and the mobility of oil angd gas produced from the reservoir into the wellbore. This study compared the viscosity, molecular weight, and particle size of the fracturing fluid after gel breakage prepared by GG and HPAM as viscosifiers, as well as evaluate their damage to the core. Results show that the viscosities of the gel-breaking fluid increased with the concentration of the viscosifier for both the HPAM-based and GG-based fracturing fluids. For the breaking fluid with the same viscosity, the molecular weight in the HPAM-based gel-breaking fluid was much larger than that in the GG-based system. Moreover, for the gel-breaking fluid with the same viscosity, the molecular particle size of the residual polymers in the HPAM-based system was smaller than that in the GG-based system. The damage to the core with the permeability of 1 × 10^(-3)μm^(2) caused by both the HPAM-based and GG-based gel-breaking fluids decreased with the increase in the solution viscosity. For the gel-breaking fluid systems with the same viscosity(i.e., 2-4 mPa s), the damage of HPAM-based fracturing fluid to low-permeability cores was greater than the GG-based fracturing fluid(45.6%-80.2%) since it had a smaller molecular particle size, ranging from 66.2% to 77.0%. This paper proposed that the damage caused by hydraulic fracturing in rock cores was related to the partilce size of residual polymers in gel-breaking solution, rather than its molecular weight. It was helpful for screening and optimizing viscosifiers used in hydraulic f

关键词： Fracturing fluid Guar gum HPAM Gel-breaking fluid Formation damage

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Emerging progress:photochemical transformation of nitroso compounds

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Science China Chemistry 2025年第1期68卷 118-133页

作者： ze-Le Chen Qiang-Qiang Li Armido Studer jun Xuan Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials School of Chemistry&Chemical EngineeringAnhui UniversityHefei 230601China Organisch-Chemisches Institut Universitat MünsterMunster 48149Germany

Nitroso compounds have emerged as highly valuable reaction partners or reagents in organic synthesis due to their rich *** versatile profile of these compounds allows them to function as electrophiles,nucleophiles,diradicals,and radical acceptors in diverse *** recent years,notable progress has been made in harnessing photochemical reactions with nitroso compounds to prepare N,O-containing structures using mild and eco-friendly *** nitroso compounds like nitrosoarenes,acyloxy nitroso compounds,N-nitrosoamines and nitrites have received significant attention for their ability to introduce NO moieties into complex molecules that are otherwise difficult to *** this review,we provide an overview of the recent advancements in the visible light-induced conversion of nitroso compounds,with particular emphasis on their role as bifunctional reagents and acceptors of radicals,carbenes and nitrenes.

关键词： nitroso compounds photochemistry radical reaction carbene transformation nitrosoarenes

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First observation results of Macao Science Satellite-1 on lightning-induced electron precipitation

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Science China Earth Sciences 2025年第1期68卷 1-10页

作者： Yongping WANG Yixin SUN Qiugang ZONG Gaopeng LU Xudong GU ze-jun HU Bin LI Key Laboratory for Polar Science Ministry of Natural ResourcesPolar Research Institute of ChinaShanghai 200136China Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China State Key Laboratory of Lunar and Planetary Science Macao University of Science and TechnologyMacao 999078China School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China School of Electronic Information Wuhan UniversityWuhan 430072China

The Medium-energy Electron Spectrometers(MES)is a space-borne instrument onboard Macao Science Satellite-1(MSS-1)dedicated to monitoring the typical charged particle radiation characteristics in the satellite orbit and the process of their occurrence and development,including short bursts of lightning-induced electron precipitation(LEP).This paper presents the first results of the LEP measurements by the MSS-1.47 LEP events are identified with the routine operation for 3 months since satellite launch,all within the range of 1.5

关键词： Lightning-induced electron precipitation Inner radiation belts Energetic electrons Macao Science Satellite-1

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Partial multi-label learning via label-specific feature corrections

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Science China(Information Sciences) 2025年第03期68卷 95-109页

作者： jun-Yi HANG Min-Ling zhang School of Computer Science and Engineering Southeast University Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education

Partial multi-label learning（PML） allows learning from rich-semantic objects with inaccurate annotations, where a set of candidate labels are assigned to each training example but only some of them are valid. Existing approaches rely on disambiguation to tackle the PML problem, which aims to correct noisy candidate labels by recovering the ground-truth labeling information ahead of prediction model induction. However, this dominant strategy might be suboptimal as it usually needs extra assumptions that cannot be fully satisfied in real-world scenarios. Instead of label correction, we investigate another strategy to tackle the PML problem, where the potential ambiguity in PML data is eliminated by correcting instance features in a label-specific manner. Accordingly, a simple yet effective approach named PASE, i.e., partial multi-label learning via label-specific feature corrections, is proposed. Under a meta-learning framework, PASElearns to exert label-specific feature corrections so that potential ambiguity specific to each class label can be eliminated and the desired prediction model can be induced on these corrected instance features with the provided candidate labels. Comprehensive experiments on a wide range of synthetic and real-world data sets validate the effectiveness of the proposed approach.

关键词： machine learning multi-label learning partial multi-label learning label-specific features feature correction

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Some Eigenvalue Properties of Third-order Boundary Value Problems with Distributional Potentials

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Acta Mathematicae Applicatae Sinica 2025年第1期41卷 179-199页

作者： Hai-yan zhang Ji-jun AO College of Sciences Inner Mongolia University of TechnologyHohhot 010051China

Several eigenvalue properties of the third-order boundary value problems with distributional potentials are ***,we prove that the operators associated with the problems are self-adjoint and the corresponding eigenvalues are ***,the continuity and differential properties of the eigenvalues of the problems are given,especially we find the differential expressions for the boundary conditions,the coefficient functions and the ***,we show a brief application to a kind of transmission boundary value problems of the problems studied here.

关键词： third-order boundary value problems distributional potentials quasi-derivatives eigenvalues

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Development and validation of a nomogram prediction model for overall survival in patients with rectal cancer

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World Journal of Gastrointestinal Oncology 2025年第2期17卷 93-104页

作者： Ling Liang Xiao-Sheng Li ze-jun Huang Zu-Hai Hu Qian-Jie Xu Yu-Liang Yuan Wei zhang Hai-Ke Lei Chongqing Key Laboratory of Translational Research for Cancer Metastasis and Individualized Treatment Chongqing University Cancer HospitalChongqing 400030China Chongqing Cancer Multiomics Big Data Application Engineering Research Center Chongqing University Cancer HospitalChongqing 400030China Department of Health Statistics School of Public HealthChongqing Medical UniversityChongqing 400016China

BACKGROUND Rectal cancer is prevalent and associated with substantial morbidity and *** To develop a nomogram prediction model for overall survival(OS)in patients with rectal cancer by leveraging a comprehensive analysis of demographic,clinicopathological,haematological,and follow-up data to identify independent prognostic *** We conducted a prospective cohort study in China involving rectal cancer patients and applied Cox regression and least absolute shrinkage and selection operator regression to assess the significance of various variables as independent prognostic factors for *** identified factors were integrated into a nomogram model,which was evaluated for predictive accuracy via the C-index,area under the curve(AUC),calibration curve,and decision curve analysis(DCA).RESULTS Multivariate analysis revealed independent predictors of OS,including the Karnofsky performance status,age,sex,TNM stage,chemotherapy,surgery,targeted therapy,β2-microglobulin,lactate dehydrogenase,and the neutrophil-to-lymphocyte *** nomogram demonstrated a C-index of 0.80 for the training and validation cohorts,with AUC values indicating high predictive accuracy for 1-year,3-year,and 5-year *** calibration curves confirmed the model's excellent agreement with the observed survival rates,and DCA revealed the superior clinical utility of the nomogram over the TNM staging *** In this study,a novel prognostic model that accurately predicts the OS of rectal cancer patients was *** model exhibited excellent discriminatory and calibration capabilities,thus offering a reliable tool for health care professionals to estimate patient survival.

关键词： Rectal cancer Overall survival Nomogram Prognosis

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Realizing high thermoelectric performance in n-type Bi_(2)Te_(3)based thin films via post-selenization diffusion

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Journal of Materiomics 2023年第4期9卷 618-625页

作者： Yue-Xing Chen jun-ze zhang Mohammad Nisar Adeel Abbas Fu Li Guang-Xing Liang Ping Fan Zhuang-Hao Zheng Shenzhen Key Laboratory of Advanced Thin Films and Applications Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen518060China

Thermoelectric thin film has attracted a lot of attention due to its potential in fabricating micropower generator in chip sensors for internet of things(IoT).However,the undeveloped performance of n-type thermoelectric thin film limits its widely *** this work,a facile post-selenization diffusion reaction method is employed to introduce Se into Bi_(2)Te_(3)thin films,in order to optimize the carrier transport *** and theoretical calculation results indicate that the carrier concentration decreases and density of states increases after Se doping,leading to the enhancement of Seebeck ***,adjusting the diffusion reaction temperature can maintain the carrier concentration while increasing the mobility simultaneously,resulting in a high power factor of 1.5 mW/(m·K^(2)),which is eight times higher than that of the pristine Bi_(2)Te_(3)thin ***,a thin film device fabricated by the present Se-doped Bi_(2)Te_(3)thin films shows the highest output power of 60.20 nW under the temperature difference of 37 K,indicating its potential for practical use.

关键词： Thermoelectric Thin film Magnetron sputtering Bie-Tee-Se

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Boron shielding design for neutron and gamma detectors of a pulsed neutron tool

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Nuclear Science and Techniques 2025年第1期36卷 115-126页

作者： Xin-Yang Wang jun-Yan Chen Qiong zhang University of Electronic Science and Technology of China Chengdu 611731China

Shielding materials are critical for downhole pulsed neutron tool design because they directly influence the accuracy of formation measurements.A well-designed shield configuration ensures that the response of the tool is maximally representative of the formation without being affected by the tool and borehole *** study investigated the effects of boron-containing materials on neutron and gamma detectors based on a newly designed logging-while-drilling tool that is currently undergoing *** the boron content increased,the ability to absorb thermal neutrons increased *** simulation,it was proven that boron carbide(B_(4)C)can be used as an effective boron shielding material for thermal neutrons,and is therefore employed in this *** shield against thermal neutrons migrating from the mud pipes,the optimal shielding thicknesses for the near-and far-neutron detectors were determined to be 5 and 4 *** a porosity of 25 p.u.,near-neutron sensitivity exhibited a 5.6%***,to shield the capture gamma generated by thermal neutrons once they enter the tool from the mud pipe and formation,internal and external shields for the gamma detector were *** results show that the internal shield requires a boron content of 75%,whereas the external shield has a thickness of 14.2 mm thickness and a boron content of 25%to minimize the tool effect.

关键词： Nuclear well logging Pulsed neutron tool Boron shielding

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Synthesis of intermetallic PtCo fuel cell catalysts from bimetallic core@shell structured nanoparticles

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Journal of Energy Chemistry 2025年第2期101卷 1-6页

作者： Le zhang Lei Tong Shuai Li Chang-Song Ma Kun-ze Xue Hai-Wei Liang Hefei National Research Center for Physical Sciences at the Microscale Department of Chemistry University of Science and Technology of China

The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells（PEMFCs）.However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered *** we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo *** fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the *** high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic *** benefits enable us to obtain the catalyst with finely dispersed nanoparticles（～3.5 nm）and a high ordering degree of 72%.With 0.1 mgPt/cm2cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm2at 0.67 V（H2-air）,and a voltage loss of 26 mV at 0.8 A/cm2after the accelerated durability test.

关键词： Bimetallic structure Fuel cells Intermetallic PtCo Oxygen reduction reaction

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