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Cobalt-catalyzed deoxygenative borylation of diaryl ketones

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Chinese Chemical Letters 2024年第3期35卷 277-281页

作者： longqing Liu Bing zhang Yu Liu Jinbo Zhao Tao Li Wanxiang Zhao College of Chemistry and Life Science Changchun University of TechnologyChangchun 130012China State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China

Geminal diboronates and diarylmethyl boronates are versatile building blocks in synthetic *** here reported a highly efficient approach for the synthesis of gem-bisborylalkanes and diarylmethyl boronates via cobalt-catalyzed deoxygenative borylation of diaryl *** borylation protocol is compatible with a broad range of functionalized aryl groups,providing access to a wide array of boronic *** resulting boronic esters can be further transformed to various cross-coupling products and TPEs that represent important structural motifs in organic chemistry and materials science.

关键词： Bisborylalkanes Cobalt Deoxygenative borylation Ketones

Fabrication of amorphous FeCoNiCuMnP x high-entropy phosphide/carbon composites with a heterostructured fusiform morphology for efficient oxygen evolution reaction

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Journal of Materials Science & Technology 2024年第1期168卷 62-70页

作者： Yifan Zhou longqing Gao Haoyuan Chen Hao Wang Juan zhang Xiumin Li Fangfang Duo Guoqing Guan School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Graduate School of Sustainable Community Studies Hirosaki University1-BunkyochoHirosaki 036-8560Japan Graduate School of Science and Technology Hirosaki University3-BunkyochoHirosaki 036-8561Japan Xinxiang University School of Chemistry&Materials EngineeringXinxiang 453003China Energy Conversion Engineering Laboratory Institute of Regional InnovationHirosaki University3-BunkyochoHirosaki 036-8561Japan

Amorphous high-entropy materials with abundant defects,coordinatively unsaturated sites,and loosely bonded atoms could exhibit excellent electrocatalytic ***,how to fabricate such ma-terials with nanostructure as well as amorphous structure is still full of *** this work,high-entropy metal organic framework(HE-MOF)is employed as the self-sacrificial template to fabricate FeCoNiCuMnP x high-entropy phosphide/carbon(HEP/C)*** obtained composite shows a het-erostructured fusiform morphology,in which the HEP is encapsulated by a carbon layer,revealing high electron conductivity as well as rich catalytic active sites for oxygen evolution reaction(OER).Beside,it is found that there is a short-range ordered crystal structure in the amorphous phase,which is bene-ficial for revealing high OER catalytic activity as well as good *** a result,the optimum HEP/C composite shows an overpotential 239 mV@10 mA cm^(−2)with a small Tafel slope of 72.5 mV dec^(−1) for catalyzing OER in alkaline solution.

关键词： Water electrolysis Oxygen evolution reaction High-entropy MOFs High-entropy phosphides Amorphous structure

Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

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Petroleum Exploration and Development 2024年第3期51卷 715-726页

作者： ZOU Yushi LI Yanchao YANG Can zhang Shicheng MA Xinfang ZOU longqing State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249China Shale Gas E&D Project Department CNPC Chuanqing Drilling Engineering Co.Ltd.Chengdu 610052China

This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting *** effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of *** addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the *** temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak *** breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective *** TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of ***,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

关键词： shale temporary plugging and diversion fracturing multi-cluster sand jetting perforation distribution of temporary plugging agent fracture propagation law

Comparative Variance and Multiple Imputation Used for Missing Values in Land Price DataSet

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Computers, Materials & Continua 2019年第9期61卷 1175-1187页

作者： longqing zhang Xinwei zhang Liping Bai Yanghong zhang Feng Sun Changcheng Chen Macao University of Science and Technology Macao Guangdong University of Science and Technology Dongguan523083China

Based on the two-dimensional relation table,this paper studies the missing values in the sample data of land price of Shunde District of Foshan *** software was used to eliminate the insignificant factors by stepwise regression analysis;NORM software was adopted to construct the multiple imputation models;EM algorithm and the augmentation algorithm were applied to fit multiple linear regression equations to construct five different filling *** analysis is performed on the imputation data set in order to calculate the mean and variance of each data set,and the weight is determined according to the ***,comprehensive integration is implemented to achieve the imputation expression of missing *** results showed that in the three missing cases where the PRICE variable was missing and the deletion rate was 5%,the PRICE variable was missing and the deletion rate was 10%,and the PRICE variable and the CBD variable were both *** new method compared to the traditional multiple filling methods of true value closer ratio is 75%to 25%,62.5%to 37.5%,100%to 0%.Therefore,the new method is obviously better than the traditional multiple imputation methods,and the missing value data estimated by the new method bears certain reference value.

关键词： Imputation method multiple imputations probabilistic model

Cultivated Land Monitoring System Based on Dynamic Wake-Up UAV and Wireless of Distributed Storage

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Computers, Materials & Continua 2019年第8期61卷 817-828页

作者： longqing zhang Liping Bai Xinwei zhang Yanghong zhang Lei Yang Xiangdu Yan Macao University of Science and Technology Macao Guangdong University of Science and Technology Dongguan523083China

The drawbacks of the traditional multi-hop structure of wireless sensor networks(WSNS)are susceptible to reflection,scattering and diffraction,serious attenuation of signal intensity and phase deviation due to various obstacles in cultivated land environment and *** this paper,the wireless signal intensity is measured and curve fitting is done respectively in both open environment and obstacle-environment with both sending and receiving height of 0 m,1 m,and 2 *** is found out that packet loss probability is too high when an obstacle *** such a case,unmanned aerial vehicle(UAV)is introduced to activate terrestrial nodes and operation mechanism of distributed *** results show that both ground-to-air barrier-free communication and communication with obstacles can greatly reduce the energy consumption of each node and packet loss probability,thus greatly improving the reliability of UAV-WSN system.

关键词： Unmanned aerial vehicle wireless sensor network signal intensity

Difference of Visual Information Metric Based on Entropy of Primitive

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Computers, Materials & Continua 2020年第2期62卷 817-831页

作者： Yanghong zhang Feng Sun Liwei Tian Jinfeng Li longqing zhang Shengfu Lan Guangdong University of Science and Technology Dong GuanChina Lenovo(Shanghai)Information Technology Co. Ltd.ShanghaiChina 不详

Image sparse representation is a method of efficient compression and coding of image signal in the process of digital image *** after sparse representation,to enhance the transmission efficiency of the image *** of Primitive(EoP)is a statistical representation of the sparse representation of the image,which indicates the probability of each base *** on the EoP,this paper presents an image quality evaluation method-Difference of Visual Information Metric(DVIM).The principle of this method is to evaluate the image quality with the difference between the original image and the distorted *** comparative experiments between DVIM&PSNR&SSIM are carried *** was found that there was a great improvement in the image quality evaluation of geometric *** method is an effective image quality evaluation method,which overcomes the weakness of other quality evaluation methods for geometrically changing images to a certain extent,and is more consistent with the subjective observation of the human eye.

关键词： Entropy of primitive visual information visual information difference measurement

TCPW BR: A Wireless Congestion Control Scheme Base on RTT

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Computers, Materials & Continua 2020年第1期62卷 233-244页

作者： Liwei Tian Jinfeng Li longqing zhang Yu Sun Lei Yang College of Computer Science Guangdong University of Science and TechnologyDongguan523083China College of Information Technology Macao University of Science and TechnologyMacao SAR Department of Information Technology Huizhou City CollegeHuizhou516025China College of Information Engineering Guangdong Innovative Technical CollegeDongguan523960China

The wireless network is limited by the transmission medium,and the transmission process is subject to large interference and *** jitter can cause sporadic loss and is mistaken for congestion by the congestion control *** TCP Westwood protocol(referred to as TCPW)is such that it cannot distinguish between congestion loss and wireless jitter loss,which makes the congestion mechanism too sensitive and reduces bandwidth *** on this,the TCPW protocol is modified based on the estimate of the Round-Trip Time(referred to as RTT)value-called TCPW *** algorithm uses the measured smooth RTT value and divides the congestion level according to the weighted average idea to determine congestion loss and wireless jitter *** simulation results show that the TCPW BR algorithm enhances the wireless network’s ability to judge congestion and random errors.

关键词： Congestion control RTT TCP Westwood

Identifying Game Processes Based on Private Working Sets

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Computers, Materials & Continua 2020年第10期65卷 639-651页

作者： Jinfeng Li Li Feng longqing zhang Hongning Dai Lei Yang Liwei Tian Faculty of Information Technology Macao University of Science and TechnologyTaipa999078Macao Macao Institute of Systems Engineering Macao University of Science and TechnologyTaipa999078Macao

Fueled by the booming online games,there is an increasing demand for monitoring online games in various *** of the application scenarios is the monitor of computer games in school computer labs,for which an intelligent game recognition method is *** this paper,a method to identify game processes in accordance with private working sets(i.e.,the amount of memory occupied by a process but cannot be shared among other processes)is *** of the W test showed that the memory sizes occupied by the legitimate processes(e.g.,the processes of common native windows applications)and game processes followed normal *** the T-test,a significant difference was identified between the legitimate processes and C/S-based computer games,in terms of the means and variances of their private working ***,we derived the density functions of the private working sets of the considered game processes and those of the legitimate *** the private working set of a process and the derived probability density functions,the probability that the process is a legitimate process and the probability that the process is a game process can be *** comparing the two probabilities,we can easily determine whether the process is a game process or *** revealed from the test results,the recognition accuracy of this method for C/S-based computer games was approximately 90%.

关键词： Game process recognition private working set comparative analysis

RSPSSL:A novel high-fidelity Raman spectral preprocessing scheme to enhance biomedical applications and chemical resolution visualization

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Light(Science & Applications) 2024年第2期13卷 366-386页

作者： Jiaqi Hu Gina Jinna Chen Chenlong Xue Pei Liang Yanqun Xiang Chuanlun zhang Xiaokeng Chi Guoying Liu Yanfang Ye Dongyu Cui De zhang Xiaojun yu Hong Dang Wen zhang Junfan Chen Quan Tang Penglai Guo Ho-Pui Ho Yuchao Li longqing Cong Perry Ping Shum State Key Laboratory of Optical Fiber and Cable Manufacture Technology Guangdong Key Laboratory of Integrated Optoelectronics IntellisenseDepartment of EEESouthern University of Science and TechnologyShenzhen 518055China College of Optical and Electronic Technology China Jiliang UniversityHangzhou 310018China Department of Nasopharyngeal Carcinoma Sun Yat-sen University Cancer CenterState Key Laboratory of Oncology in South ChinaCollaborative Innovation Center for Cancer MedicineGuangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and TherapyGuangzhou 510060China Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Nephrology Chaozhou People’s HospitalChaozhou 521011China Clinical Research Design Division Sun Yatsen Memorial HospitalGuangzhouGuangdong 510120China School of Automation Northwestern Polytechnical UniversityXi’anShaanxi 710072China Department of Biomedical Engineering The Chinese University of Hong KongHong KongChina Guangdong Provincial Key Laboratory of Nanophotonic Manipulation Institute of NanophotonicsJinan UniversityGuangzhou 511443China

Raman spectroscopy has tremendous potential for material analysis with its molecular fingerprinting capability in many branches of science and *** is also an emerging omics technique for metabolic profiling to shape precision ***,precisely attributing vibration peaks coupled with specific environmental,instrumental,and specimen noise is *** Raman spectral preprocessing to remove statistical bias noise and sample-related errors should provide a powerful tool for valuable information ***,we propose a novel Raman spectral preprocessing scheme based on self-supervised learning(RSPSSL)with high capacity and spectral *** can preprocess arbitrary Raman spectra without further training at a speed of~1900 spectra per second without human *** experimental data preprocessing trial demonstrated its excellent capacity and signal fidelity with an 88%reduction in root mean square error and a 60%reduction in infinite norm(L__(∞))compared to established *** this advantage,it remarkably enhanced various biomedical applications with a 400%accuracy elevation(ΔAUC)in cancer diagnosis,an average 38%(few-shot)and 242%accuracy improvement in paraquat concentration prediction,and unsealed the chemical resolution of biomedical hyperspectral images,especially in the spectral fingerprint *** precisely preprocessed various Raman spectra from different spectroscopy devices,laboratories,and diverse *** scheme will enable biomedical mechanism screening with the label-free volumetric molecular imaging tool on organism and disease metabolomics profiling with a scenario of high throughput,cross-device,various analyte complexity,and diverse applications.

关键词： spectral scheme resolution