Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.

Detecting and monitoring of water inrush in tunnels and coal mines using direct current resistivity method:A review

Detecting, real-time monitoring and early warning of underground water-bearing structures are critically important issues in prevention and mitigation of water inrush hazards in underground engineering. Direct current （DC） resistivity method is a widely used method for routine detection, advanced detection and real-time monitoring of water-bearing structures, due to its high sensitivity to groundwater. In this study, the DC resistivity method applied to underground engineering is reviewed and discussed, including the observation mode, multiple inversions, and real-time monitoring. It is shown that a priori information constrained inversion is desirable to reduce the non-uniqueness of inversion, with which the accuracy of detection can be significantly improved. The focused resistivity method is prospective for advanced detection;with this method, the flanking interference can be reduced and the detection dis-tance is increased subsequently. The time-lapse resistivity inversion method is suitable for the regions with continuous conductivity changes, and it can be used to monitor water inrush in those regions. Based on above-mentioned features of various methods in terms of benefits and limitations, we propose a three-dimensional （3D） induced polarization method characterized with multi-electrode array, and introduce it into tunnels and mines combining with real-time monitoring with time-lapse inversion and cross-hole resistivity method. At last, the prospective applications of DC resistivity method are discussed as follows： （1） available advanced detection technology and instrument in tunnel excavated by tunnel boring machine （TBM）, （2） high-resolution detection method in holes, （3） four-dimensional （4D） monitoring technology for water inrush sources, and （4） estimation of water volume in water-bearing structures.

Implementation of a One-Dimensional Enthalpy Sea-Ice Model in a Simple Pycnocline Prediction Model for Sea-Ice Data Assimilation Studies

To further explore enthalpy-based sea-ice assimilation, a one-dimensional （1D） enthalpy sea-ice model is implemented into a simple pycnocline prediction model. The 1D enthalpy sea-ice model includes the physical processes such as brine expulsion, flushing, and salt diffusion. After being coupled with the atmosphere and ocean components, the enthalpy sea-ice model can be integrated stably and serves as an important modulator of model variability. Results from a twin experiment show that the sea-ice data assimilation in the enthalpy space can produce smaller root-mean-square errors of model variables than the traditional scheme that assimilates the observations of ice concentration, especially for slow-varying states. This study provides some insights into the improvement of sea-ice data assimilation in a coupled general circulation model.

Glacial Thermohaline Circulation and Climate:Forcing from the North or South?

Based on the evidence available from both observations and model simulations, the author proposes a view that may provide a unified interpretation of the North Atlantic thermohaline variability. Because of the slow response time of the Southern Ocean （millennia） and the relatively faster response time of the North Atlantic （centuries）, the North Atlantic thermohaline circulation is controlled predominantly by the climate forcing over the Southern Ocean at the long glacial cycle timescales, but by the North Atlantic climate forcing at the short millennial timescaies.

Impact of the Time Scale of Model Sensitivity Response on Coupled Model Parameter Estimation

That a model has sensitivity responses to parameter uncertainties is a key concept in implementing model parameter es- timation using filtering theory and methodology. Depending on the nature of associated physics and characteristic variability of the fluid in a coupled system, the response time scales of a model to parameters can be different, from hourly to decadal. Unlike state estimation, where the update frequency is usually linked with observational frequency, the update frequency for parameter estimation must be associated with the time scale of the model sensitivity response to the parameter being esti- mated. Here, with a simple coupled model, the impact of model sensitivity response time scales on coupled model parameter estimation is studied. The model includes characteristic synoptic to decadal scales by coupling a long-term varying deep ocean with a slow-varying upper ocean forced by a chaotic atmosphere. Results show that, using the update frequency deter- mined by the model sensitivity response time scale, both the reliability and quality of parameter estimation can be improved significantly, and thus the estimated parameters make the model more consistent with the observation. These simple model results provide a guideline for when real observations are used to optimize the parameters in a coupled general circulation model for improving climate analysis and prediction initialization.

Research and Practice on College Students’Innovation and Entrepreneurship Education

Strengthening the education of innovation and entrepreneurship is one of the important tasks of China’s higher education reform and development.Entrepreneurship Education should focus on setting pioneering genetic code for future generations.Essentially,it is an education innovation-oriented entrepreneurial revolution of human resource development.Technological innovation is strategic support to improve social productivity and comprehensive national strength,which should be placed at the core of national overall development.For China’s higher education,it proposes more new requirements.Serious discussion on the innovation education of college students is needed.Through practice,improvements in the quality of innovation and entrepreneurship education will be achieved.

改良后外侧入路半髋置换治疗股骨颈骨折的早期疗效

目的探讨保留短外旋肌群的后外侧手术入路(CPP)人工股骨头置换治疗股骨颈骨折的临床疗效。方法回顾性分析上海交通大学医学院苏州九龙医院2019年1月至2022年1月共91例人工双极股骨头置换的患者。根据后外侧入路是否保留短外旋肌群分为常规组和CPP组,常规组常规切断短外旋肌群,CPP组为改良后外侧入路保留短外旋肌群。观察两组围手术期切口长度,手术时间,出血量,住院时间和疼痛等指标并进行卡方检验或t检验,随访术后并发症情况并对髋关节功能及疼痛进行评分。结果常规组50例患者,其中男15例,女35例,平均年龄(80±7)岁,CPP组41例患者,男15例,女26例,平均年龄(80±6)岁。常规组患者的手术时间、切口长度及住院时间更长,失血量较CPP组更多(t=3.192、4.553、2.968、5.835,均为P<0.05)。常规组患者术后1个月Harris评分明显低于CPP组(t=6.705,P<0.05),而术后3个月Harris评分差异则无统计学意义(t=1.484,P>0.05)。两组患者术前疼痛视觉模拟评分(VAS)差异无统计学意义(t=0.148,P>0.05),术后第1天VAS评分常规组高于CPP组(t=4.215,P<0.05)。术后总体并发症发生率两组差异无统计学意义(χ^(2)=0.675,P>0.05)。结论采用CPP手术入路,不仅减少了手术创伤,缩短了患者回归正常生活时间,同时增加了髋关节的稳定性,理论上可降低术后脱位风险,更推荐用于高龄人工股骨头置换患者。

Possible obliquity-forced warmth in southern Asia during the last glacial stage

Orbital-scale global climatic changes during the late Quaternary are dominated by high-latitude influenced~100,000-year global ice-age cycles and monsoon influenced~23,000-year low-latitude hydroclimate variations.However,the shortage of highly-resolved land temperature records remains a limiting factor for achieving a comprehensive understanding of long-term low-latitude terrestrial climatic changes.Here,we report paired mean annual air temperature(MAAT)and monsoon intensity proxy records over the past 88,000 years from Lake Tengchongqinghai in southwestern China.While summer monsoon intensity follows the~23,000-year precession beat found also in previous studies,we identify previously unrecognized warm periods at 88,000-71,000 and 45,000-22,000 years ago,with 2-3℃amplitudes that are close to our recorded full glacial-interglacial range.Using advanced transient climate simulations and comparing with forcing factors,we find that these warm periods in our MAAT record probably depends on local annual mean insolation,which is controlled by Earth’s~41,000-year obliquity cycles and is anti-phased to annual mean insolation at high latitudes.The coincidence of our identified warm periods and intervals of high-frequent dated archaeological evidence highlights the importance of temperature on anatomically modern humans in Asia during the last glacial stage.

Model–proxy comparison for overshoot phenomenon of Atlantic thermohaline circulation at Bφlling–Allerφd

The overshoot phenomenon of the Atlantic thermohaline circulation(THC) is a transient climate response to meltwater forcing and could induce intense climate change by increasing the magnitudes of Atlantic THC changes at the end of meltwater discharges. This phenomenon was formally presented with the successfully simulated Bφlling–Allerφd(BA) event in the first transient simulation of the last deglaciation with fully coupled model NCAR-CCSM3(TraCE-21K). Currently, not all proxy records of Atlantic THC support the occurrence of the THC overshoot at BA. Commonly used THC proxy from Bermuda Rise(GGC5) does not exhibit THC overshoot at BA but other proxies such as TTR-451 at Eirik Drift do. How to interpret this regional discrepancy of proxy records is a key question for the validation of the Atlantic THC overshoot at BA. Here, we show that the vigor of deep circulation varies regionally during the Atlantic THC overshoot at BA in TraCE-21 K simulation, and this regional discrepancy in the simulation is consistent with that in the marine sediment records in North Atlantic. The consistent model–proxy evidence supports the occurrence of Atlantic THC overshoot at BA.

Large training dataset is crucial for analogue-based precipitation reconstruction during the early Holocene

A long-standing question regarding the Holocene evolution of the East Asian Summer Monsoon(EASM)is whether it peaked during the early Holocene(EH)as inferred from rainfall-related proxy records[1,2],or during the mid-Holocene as inferred from ecoenvironmental records from northern China[3,4].Cheng et al.

Influence and mechanism of solar radiation intensity on the interdecadal variability of strong Meiyu events during historical periods

Most recent studies on Meiyu over the middle and lower reaches of the Yangtze River(MLRYR)have focused on its interannual variability or the mechanism of certain abnormal events.The influence and physical mechanism of solar radiation intensity on the interdecadal frequency of strong Meiyu events over the MLRYR during historical periods were investigated using reconstructed precipitation data,reconstructed solar radiation data,and model simulation data.First,according to the solar radiation intensity,the Ming and Qing Dynasties(1470-1850)were divided into three periods of strong solar radiation and three periods of weak solar radiation.It was found that during the periods of strong solar radiation,the frequency of strong Meiyu events was significantly higher than that during the periods of weak solar radiation in the reconstructed precipitation data and model simulations.Mechanism analyses show that during the periods of strong solar radiation,the Western Pacific Subtropical High(WPSH)is stronger,and the blocking highs over the middle-high-latitudes are also stronger,which is conducive to the continuous convergence of the southward cold air and the northward warm and humid air flow at the MLRYR.Therefore,a circulation spatial pattern conducive to the occurrence of strong Meiyu events is then induced.The probability distributions of precipitation also show that,during periods of strong solar radiation,changes in circulation patterns cause the probability distribution of precipitation to shift significantly to the right,increasing the probability of strong Meiyu events occurring on the right side of the probability distribution.

Globe230k:A Benchmark Dense-Pixel Annotation Dataset for Global Land Cover Mapping

Global land cover map provides fundamental information for understanding the relationship between global environmental change and human settlement.With the development of data-driven deep learning theory,semantic segmentation network has largely facilitated the global land cover mapping activity.However,the performance of semantic segmentation network is closely related to the number and quality of training data,and the existing annotation data are usually insufficient in quantity,quality,and spatial resolution,and are usually sampled at local region and lack diversity and variability,making data-driven model difficult to extend to global scale.Therefore,we proposed a large-scale annotation dataset(Globe230k)for semantic segmentation of remote sensing image,which has 3 superiorities:(a)large scale:the Globe230k dataset includes 232,819 annotated images with a size of 512×512 and a spatial resolution of 1 m,including 10 firstlevel categories;(b)rich diversity:the annotated images are sampled from worldwide regions,with coverage area of over 60,000 km^(2),indicating a high variability and diversity;(c)multimodal:the Globe230k dataset not only contains RGB bands but also includes other important features for Earth system research,such as normalized differential vegetation index(NDVI),digital elevation model(DEM),vertical-vertical polarization(VV)bands,and vertical-horizontal polarization(VH)bands,which can facilitate the multimodal data fusion research.We used the Globe230k dataset to test several state-of-the-art semantic segmentation algorithms and found that it is able to evaluate algorithms in multiple aspects that are crucial for characterizing land covers,including multiscale modeling,detail reconstruction,and generalization ability.The dataset has been made public and can be used as a benchmark to promote further development of global land cover mapping and semantic segmentation algorithm development.