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Variable projection algorithms with sparse constraint for separable nonlinear models

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Control Theory and Technology 2024年第1期22卷 135-146页

作者： Hui-Lang Xu Guang-yong chen Si-Qing cheng Min Gan Jing chen College of Computer and Data Science Fuzhou UniversityFuzhou350116FujianChina Fujian Key Laboratory of Network Computing and Intelligent Information Processing Fuzhou UniversityFuzhou350116FujianChina Key Laboratory of Intelligent Metro of Universities in Fujian Fuzhou UniversityFuzhou350116FujianChina Engineering Research Center of Big Data Intelligence Ministry of EducationFuzhou UniversityFuzhou350116FujianChina School of Science Jiangnan UniversityWuxi214122JiangsuChina

Separable nonlinear models are widely used in various fields such as time series analysis, system modeling, and machine learning, due to their flexible structures and ability to capture nonlinear behavior of data. However, identifying the parameters of these models is challenging, especially when sparse models with better interpretability are desired by practitioners. Previous theoretical and practical studies have shown that variable projection (VP) is an efficient method for identifying separable nonlinear models, but these are based on \(L_2\) penalty of model parameters, which cannot be directly extended to deal with sparse constraint. Based on the exploration of the structural characteristics of separable models, this paper proposes gradient-based and trust-region-based variable projection algorithms, which mainly solve two key problems: how to eliminate linear parameters under sparse constraint;and how to deal with the coupling relationship between linear and nonlinear parameters in the model. Finally, numerical experiments on synthetic data and real time series data are conducted to verify the effectiveness of the proposed algorithms.

关键词： Variable projection(VP) Non-smooth constraint Separable nonlinear models

Confined Mn^(2+) enables effective aerobic oxidation catalysis

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Science China Chemistry 2024年第5期67卷 1545-1553页

作者： Desheng Yuan Sicong Ma Xiao Kong Chi Zhang Lin chen chengsheng Yang Lihua Wang Zhen Liu Lin Ye yongmei Liu Rui Ma zhi-Pan Liu Yifeng Zhu yong Cao Xinhe Bao Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Department of Chemistry Shanghai Key Laboratory of Molecular Catalysis and Innovative MaterialsCollaborative Innovation Center of Chemistry for Energy MaterialsFudan UniversityShanghai 200438China Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Institute of Advanced Fluorine-Containing Materials Zhejiang Normal UniversityJinhua 321004China State Key Laboratory of Catalysis National Laboratory for Clean EnergyCollaborative Innovation Center of Chemistry for Energy MaterialsDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Effective and mild activation of O_(2) is essential but challenging for aerobic oxidation. In heterogeneous catalysis, high-valence manganese oxide(e.g., +4) is known to be active for the oxidation, whereas divalent MnO is ineffective due to its limited capacity to supply surface oxygen and its thermodynamically unstable structure when binding O_(2) in reaction conditions. Inspired by natural enzymes that rely on divalent Mn^(2+), we discovered that confining Mn^(2+) onto the Mn_(2)O_(3) surface through a dedicated calcination process creates highly active catalysts for the aerobic oxidation of 5-hydroxymethylfurfural, benzyl alcohol, and *** Mn_(2)O_(3)-confined Mn^(2+) is undercoordinated and efficiently mediates O_(2) activation, resulting in 2–3 orders of magnitude higher activity than Mn_(2)O_(3) alone. Through low-temperature infrared spectroscopy, we distinguished low-content Mn^(2+) sites at Mn_(2)O_(3) surface, which are difficult to be differentiated by X-ray photoelectron spectroscopy. The combination of in-situ energydispersive X-ray absorption spectroscopy and X-ray diffraction further provides insights into the formation of the newly identified active Mn^(2+) sites. By optimizing the calcination step, we were able to increase the catalytic activity threefold *** finding offers promising frontiers for exploring active oxidation catalysts by utilizing the confinement of Mn^(2+)and oftenignored calcination skills.

关键词： confinement catalysis manganese oxide aerobic oxidation divalent Mn^(2+) operando spectroscopies

Insight into structural degradation of NCMs under extreme fast charging process

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Rare Metals 2024年第1期43卷 41-50页

作者： Yu Tang Xing-Yu Wang Jin-Can Ren Bo-Wen chen zhi-yong Huang Wei Wang Ya-Lan Huang Bing-Hao Zhang Si Lan Zhang-Long He Qi Liu Hao He Department of Physics City University of Hong KongHong Kong 999077China Shenzhen Research Institute City University of Hong KongShenzhen 518057China College of Materials Science and Engineering Changsha University of Science&TechnologyChangsha 410114China

Lithium-ion batteries(LIBs)with extreme fast charging(XFC)capability are considered an effective way to alleviate range anxiety for electric vehicle(EV)*** to the high ionic and electronic conductivity of LiNi_(x)Co_(y)Mn_zO_(2)(x+y+z=1,NCM)cathodes,the inevitable Li plating of graphite in NCM|graphite cell is usually identified as a key bottleneck for XFC ***,the capacity decay mechanism of cathode materials under XFC has not been fully *** this work,three typical NCM cathode materials with different Ni fractions were chosen and their electrochemical performances under XFC associated with structural evolution were investigated.A faster capacity decay of NCMs under XFC conditions is observed,especially for Ni-rich ***-situ X-ray diffraction(XRD)reveals that the multiple caxis parameters appear at the high-voltage regions in Nirich NCMs,which is probably triggered by the larger obstruction of Li(de)***,NCMs with moderate Ni fraction also present a similar trend under XFC *** phenomenon is more detrimental to the structural and morphological stability,resulting in a faster capacity decay than that under low current *** work provides new insight into the degradation mechanism of NCMs under XFC conditions,which can promote the development of NCM cathode materials with XFC capability.

关键词： Lithium-ion batteries Ni fraction Extreme fast charging Structural evolution

Quantum Neural Network for Quantum Neural Computing

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Research 2024年第1期2023卷 71-80页

作者： Min-Gang Zhou zhi-Ping Liu Hua-Lei Yin chen-Long Li Tong-Kai Xu Zeng-Bing chen National Laboratory of Solid State Microstructures School of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China MatricTime Digital Technology Co.Ltd. Nanjing 211899China

Neural networks have achieved impressive breakthroughs in both industry and *** to effectively develop neural networks on quantum computing devices is a challenging open ***,we propose a new quantum neural network model for quantum neural computing using(classically controlled)single-qubit operations and measurements on real-world quantum systems with naturally occurring environment-induced decoherence,which greatly reduces the difficulties of physical *** model circumvents the problem that the state-space size grows exponentially with the number of neurons,thereby greatly reducing memory requirements and allowing for fast optimization with traditional optimization *** benchmark our model for handwritten digit recognition and other nonlinear classification *** results show that our model has an amazing nonlinear classification ability and robustness to ***,our model allows quantum computing to be applied in a wider context and inspires the earlier development of a quantum neural computer than standard quantum computers.

关键词： quantum thereby breakthrough

Cone-beam computed tomography noise reduction method based on U-Net with convolutional block attention module in proton therapy

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Nuclear Science and Techniques 2024年第7期35卷 89-100页

作者： Xing-Yue Ruan Xiu-Fang Li Meng-Ya Guo Mei chen Ming Lv Rui Li zhi-Ling chen Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai201800China University of Chinese Academy of Sciences Beijing100049China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai201210China Department of Radiation Oncology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai200025China Shanghai Key Laboratory of Proton therapy Shanghai201801China

Cone-beam computed tomography(CBCT) is mostly used for position verification during the treatment process. However,severe image artifacts in CBCT hinder its direct use in dose calculation and adaptive radiation therapy re-planning for proton therapy. In this study, an improved U-Net neural network named CBAM-U-Net was proposed for CBCT noise reduction in proton therapy, which is a CBCT denoised U-Net network with convolutional block attention modules. The datasets contained 20 groups of head and neck images. The CT images were registered to CBCT images as ground truth. The original CBCT denoised U-Net network, sCTU-Net, was trained for model performance comparison. The synthetic CT(SCT) images generated by CBAM-U-Net and the original sCTU-Net are called CBAM-SCT and U-Net-SCT images, respectively. The HU accuracies of the CT, CBCT, and SCT images were compared using four metrics: mean absolute error(MAE), root mean square error(RMSE), peak signal-to-noise ratio(PSNR), and structure similarity index measure(SSIM). The mean values of the MAE, RMSE, PSNR, and SSIM of CBAM-SCT images were 23.80 HU, 64.63 HU, 52.27 dB, and 0.9919, respectively,which were superior to those of the U-Net-SCT images. To evaluate dosimetric accuracy, the range accuracy was compared for a single-energy proton beam. The γ-index pass rates of a 4 cm × 4 cm scanned field and simple plan were calculated to compare the effects of the noise reduction capabilities of the original U-Net and CBAM-U-Net on the dose calculation results. CBAM-U-Net reduced noise more effectively than sCTU-Net, particularly in high-density tissues. We proposed a CBAM-U-Net model for CBCT noise reduction in proton therapy. Owing to the excellent noise reduction capabilities of CBAM-U-Net, the proposed model provided relatively explicit information regarding patient tissues. Moreover, it maybe be used in dose calculation and adaptive treatment planning in the future.

关键词： Proton therapy Cone-beam CT CBAM-U-Net γ-index

A High-Accuracy Curve Boundary Recognition Method Based on the Lattice Boltzmann Method and Immersed Moving Boundary Method

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2533-2557页

作者： Jie-Di Weng yong-Zheng Jiang Long-Chao chen Xu Zhang Guan-yong Zhang Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtan411201China School of Mechanical Engineering Hunan Chemical Vocational Technology CollegeZhuzhou412000China

Applying numerical simulation technology to investigate fluid-solid interaction involving complex curved bound-aries is vital in aircraft design,ocean,and construction ***,current methods such as Lattice Boltzmann(LBM)and the immersion boundary method based on solid ratio(IMB)have limitations in identifying custom curved ***,IBM based on velocity correction(IBM-VC)suffers from inaccuracies and numerical ***,this study introduces a high-accuracy curve boundary recognition method(IMB-CB),which identifies boundary nodes by moving the search box,and corrects the weighting function in LBM by calculating the solid ratio of the boundary nodes,achieving accurate recognition of custom curve *** addition,curve boundary image and dot methods are utilized to verify *** findings revealed that IMB-CB can accurately identify the boundary,showing an error of less than 1.8%with 500 ***,the flow in the custom curve boundary and aerodynamic characteristics of the NACA0012 airfoil are calculated and compared to *** showed that IMB-CB yields lower lift and drag coefficient errors than IBM-VC,with a 1.45%drag coefficient *** addition,the characteristic curve of IMB-CB is very stable,whereas that of IBM-VC is *** the moving boundary problem,LBM-IMB-CB with discrete element method(DEM)is capable of accurately simulating the physical phenomena of multi-moving particle flow in complex curved *** research proposes a new curve boundary recognition method,which can significantly promote the stability and accuracy of fluid-solid interaction simulations and thus has huge applications in engineering.

关键词： Fluid-solid interaction curve boundary recognition method Lattice Boltzmann method immersed moving boundary method

Nomogram to predict severe retinopathy of prematurity in Southeast China

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International Journal of Ophthalmology(English edition) 2024年第2期17卷 282-288页

作者： Dan Liu Xing-yong Li Hong-Wu He Ka-Lu Jin Ling-Xia Zhang Yang Zhou zhi-Min Zhu chen-chen Jiang Hai-Jian Wu Sui-Lian Zheng Department of Ophthalmology the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical UniversityWenzhou 325027Zhejiang ProvinceChina Eye Hospital and School of Ophthalmology and Optometry Wenzhou Medical UniversityWenzhou 325027Zhejiang ProvinceChina Taizhou Optometry Hospital Taizhou 318001Zhejiang ProvinceChina Department of Ophthalmology Jiaxing Maternity and Child Health Care HospitalJiaxing 314009Zhejiang ProvinceChina Department of Ophthalmology Taizhou Women and Children’s Hospital of Wenzhou Medical UniversityTaizhou 318001Zhejiang ProvinceChina Clinical Medical Research Center the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical UniversityWenzhou 325027Zhejiang ProvinceChina Department of Ophthalmology Taizhou Municipal HospitalTaizhou 318099Zhejiang ProvinceChina

AIM:To define the predictive factors of severe retinopathy of prematurity(ROP)and develop a nomogram for predicting severe ROP in southeast ***:Totally 554 infants diagnosed with ROP hospitalized in the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University and hospitalized in Taizhou Women and Children’s Hospital were *** data and 43 candidate predictive factors of ROP infants were collected *** regression model was used to identify predictive factors of severe ROP and to propose a nomogram for individual risk prediction,which was compared with WINROP model and Digirop-Birth ***:Infants from the Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University(n=478)were randomly allocated into training(n=402)and internal validation group(n=76).Infants from Taizhou Women and Children’s Hospital were set as external validation group(n=76).Severe ROP were found in 52 of 402 infants,12 of 76 infants,and 7 of 76 infants in training group,internal validation group,and external validation group,*** weight[odds ratio(OR),0.997;95%confidence interval(CI),0.996-0.999;P<0.001],multiple births(OR,1.885;95%CI,1.013-3.506;P=0.045),and non-invasive ventilation(OR,0.288;95%CI,0.146-0.570;P<0.001)were identified as predictive factors for the prediction of severe ROP,by univariate analysis and multivariate *** predicting severe ROP based on the internal validation group,the areas under receiver operating characteristic curve(AUC)was 78.1(95%CI,64.2-92.0)for the nomogram,32.9(95%CI,15.3-50.5)for WINROP model,70.2(95%CI,55.8-84.6)for Digirop-Birth *** external validation group,AUC of the nomogram was also higher than that of WINROP model and Digirop-Birth model(80.2 versus 51.1 and 63.4).The decision curve analysis of the nomogram demonstrated better clinical efficacy than that of WINROP model and Digirop-Birth *** calibration curves demonst

关键词： retinopathy of prematurity nomogram predictive factor birth weight multiple births non-invasive ventilation

Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 531-538页

作者： Wenxing Cao Jiancheng Shu Jiaming chen Zihan Li Songshan Zhou Shushu Liao Mengjun chen yong Yang Key Laboratory of Solid Waste Treatment and Resource Recycle(SWUST) Ministry of EducationSouthwest University of Science and TechnologyMianyang 621010China School of Chemistry and Chemical Engineering Chongqing UniversityChongqing 400044China Daxin Manganese Mining Branch of South Manganese Group Limited Chongzuo 532315China

Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy *** this study,the slurry electrolysis technique was used to recover high-purity Fe powder from *** effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were *** to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be *** leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 *** addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.

关键词： iron-rich electrolytic manganese residue slurry electrolysis high-purity iron powder leaching efficiency current efficiency

Controlled fluorescent switch based on a cation grease/brake rotor system of pillar[5]arene

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Chinese Chemical Letters 2024年第3期35卷 5-7页

作者： Wei-Lei Zhou Siwei Wang yong chen College of Chemistry and Material Science Inner Mongolia Key Laboratory of Chemistry for Nature Products and Synthesis for Functional MoleculesInnovation Team of Optical Functional Molecular DevicesInner Mongolia Minzu UniversityTongliao 028000China College of Chemistry Nankai UniversityTianjin 300071China

In recent years,molecular shuttles,motors,pumps,and elevators,*** specifically respond external physical or chemical stimuli including light,temperature,pH,redox,solvent and chemical additive to change the structure a... 详细信息

关键词： additive system showing