Pit density reduction for AlN epilayers grown by molecular beam epitaxy using Al modulation method

We have investigated homoepitaxy of AlN films grown by molecular beam epitaxy on AlN/sapphire templates byadopting both the continuous growth method and the Al modulation epitaxy(AME)growth method.The continuous growthmethod encounters significant challenges in controlling the growth mode.As the precise Al/N=1.0 ratio is difficult toachieve,either the excessive Al-rich or N-rich growth mode occurs.In contrast,by adopting the AME growth method,sucha difficulty has been effectively overcome.By manipulating the supply time of the Al and nitrogen sources,we were able toproduce AlN films with much improved surface morphology.The first step of the AME method,only supplying Al atoms,is important to wet the surface and the Al adatoms can act as a surfactant.Optimization of the initial Al supply time caneffectively reduce the pit density on the grown AlN surface.The pits density dropped from 12 pits/μm^(2)to 1 pit/μm^(2)andthe surface roughness reduced from 0.72 nm to 0.3 nm in a 2×2μm^(2)area for the AME AlN film homoepitaxially grownon an AlN template.

基于PIT技术的老口航运枢纽鱼道通行效率及鱼类行为分析

PIT(passive integrated transponder)射频芯片跟踪作为一种监测方法,被广泛应用于鱼类洄游行为监测及评估鱼道过鱼效率。为了解鱼类在郁江老口航运枢纽鱼道的上溯速度、昼夜特征行为及鱼道通行效率等情况,从而为鱼道设计提供更多参考,该研究以优势种鲮(Cirrhinus molitorella)为试验对象,搭半双工(half duplex,HDX)PIT标记射频芯片跟踪系统,在鱼道中设置了5个监测断面。有效试验鱼共63尾,全部为野生个体,全长范围为16.00~23.50 cm,均值为(19.05±1.49)cm。试验发现,试验鱼在白天活动较为活跃,夜晚则处于休息状态;多数个体在标记放流后上行至第一个天线所需时间超过10 h;标记试验鱼通过整个鱼道的历时为648~5359 min,总通行效率为50.79%。研究可为国内过鱼设施通行效率量化及鱼道中鱼类上溯行为特征研究提供参考。

PIT标志技术在鱼类资源保护中的应用研究

PIT(passive integrated transponder)标记因其具有储存的信息量大、持久可靠、识别迅速、性能稳定、唯一性、体积小等优点,被广泛用于鱼类种群动态、增殖放流、生境选择和过鱼设施等研究领域,成为鱼类资源保护研究的重要手段之一。介绍了PIT标志技术的工作原理,梳理了1991—2020年国内外PIT标志技术在鱼类资源保护中的应用研究,探讨了PIT标志技术在鱼类种群动态、过鱼设施、增殖放流以及生境选择等研究中的成效。通过对比国内外PIT标志技术的应用研究情况,结合国内鱼类资源保护工作的实际需求与研究现状,分析了国外PIT标志技术应用研究对我国开展相关工作的指导作用,指出PIT标志技术在我国应用研究的发展方向,提出加强PIT标志技术在过鱼设施的长期监测、鱼类增殖放流、鱼类种群动态与鱼类生境选择等方面的应用研究,提升PIT标志技术在鱼类资源保护研究中的技术水平,制定PIT标记应用的技术规范,建立我国PIT标记监测网络平台等建议,以满足鱼类科研、保护和管理的需要。

pit分型联合jnet分型在结直肠息肉病理分类诊断中的应用价值

目的:探究pit分型联合jnet分型在结直肠息肉病理分类判断中的应用价值。方法:选取102例结直肠息肉患者(共134个病灶)为研究对象,所有患者均接受内镜及病理检查。以病理诊断结果为金标准,比较pit分型、jnet分型对各病理分类结直肠息肉的诊断符合率。采用Kappa检验分析pit分型、jnet分型单独及联合诊断结直肠息肉性质的结果与病理诊断结果的一致性。结果:pit分型II型与病理诊断为非肿瘤性息肉的符合率为88.00%(22/25);IIIL型与病理诊断为管状腺瘤的符合率为91.38%(53/58);Ⅳ型与病理诊断为绒毛状腺瘤的符合率为80.00%(16/20);Ⅵ型与病理诊断为高级别上皮内瘤变(HGIN)/粘膜下浅层浸润癌(SM-s)的符合率为85.19%(23/27);VN型与病理诊断粘膜下深层浸润癌(SM-d)的符合率为50.00%(2/4)。jnet分型1型与病理诊断为非肿瘤性息肉的符合率为80.00%(20/25);2A型与病理诊断为腺瘤性息肉的符合率为84.62%(66/78);2B型与病理诊断为HGIN/SM-s的符合率为92.59%(25/27);3型与病理诊断为SM-d的符合率为100.00%(4/4)。pit分型、jnet分型及pit分型联合jnet分型诊断肿瘤性结直肠息肉的Kappa值分别为0.809、0.714、0.925。pit分型、jnet分型单独及联合诊断结直肠息肉的敏感度分别为88.00%、80.00%、92.00%,特异度分别为95.41%、93.58%、99.08%,阳性预测值分别为81.46%、74.07%、95.83%,阴性预测值分别为97.20%、95.33%、98.18%,准确度分别为94.03%、91.04%、97.76%。结论:pit分型联合jnet分型在结直肠息肉病理分类诊断中,可提高诊断结直肠息肉性质的准确性,为临床治疗决策提供指导。

The role of the auxin-response genes MdGH3.1 and MdSAUR36 in bitter pit formation in apple

Apples often exhibit bitter pits in response to metabolic disorders during ripening and storage;however, the mechanisms underlying the bitter pit(BP) development remain unclear. Here, metabolome and transcriptome analyses were performed to investigate BP pulp of 'Fuji'. Two auxin-response genes, MdGH3.1 and MdSAUR36, were screened. Their expression as well as the auxin content in BP pulp were found to be higher than those in healthy pulp(P < 0.01). In the field, excess CO(NH2)2increased the incidence of BP. Moreover, the auxin content and MdGH3.1 expression increased in apples after nitrogen fertilization. On Day 30 before harvest, the two genes were transiently transferred to the fruit, and 20.69% and 23.21% of BP fruits were harvested. After 10 μmol·L-1auxin was infiltrated at low pressure into postharvest fruit, the increase in MdGH3.1 expression occurred earlier than that in MdSAUR36. MdGH3.1 increased the expression of MdSAUR36, but MdSAUR36 did not increase expression of MdGH3.1. Therefore, we suggest that MdGH3.1 acts upstream of MdSAUR36 during BP formation and that these genes induce BP formation by regulating auxin and phenylpropanoid biosynthesis.

Rockburst criterion and evaluation method for potential rockburst pit depth considering excavation damage effect

Excavation-induced disturbances in deep tunnels will lead to deterioration of rock properties and formation of excavation damaged zone(EDZ).This excavation damage effect may affect the potential rockburst pit depth.Taking two diversion tunnels of Jinping II hydropower station for example,the relationship between rockburst pit depth and excavation damage effect is first surveyed.The results indicate that the rockburst pit depth in tunnels with severe damage to rock masses is relatively large.Subsequently,the excavation-induced damage effect is characterized by disturbance factor D based on the Hoek-Brown criterion and wave velocity method.It is found that the EDZ could be further divided into a high-damage zone(HDZ)with D=1 and weak-damage zone(WDZ),and D decays from one to zero linearly.For this,a quantitative evaluation method for potential rockburst pit depth is established by presenting a three-element rockburst criterion considering rock strength,geostress and disturbance factor.The evaluation results obtained by this method match well with actual observations.In addition,the weakening of rock mass strength promotes the formation and expansion of potential rockburst pits.The potential rockburst pit depth is positively correlated with HDZ and WDZ depths,and the HDZ depth has a significant contribution to the potential rockburst pit depth.

Pitting corrosion initiated by SiO_(2)-MnO-Cr_(2)O_(3)-Al_(2)O_(3)-based inclusions in a 304 stainless steel

The influence of the aluminum content on the pitting corrosion of a 304 stainless steel by a Cl−solution was investigated.The number,area,and composition of non-metallic inclusions were modified by the addition of aluminum in the steel,which was responsible for the variation of the corrosion degree of the 304 stainless steel.Inclusions detection,corrosion test,electrochemical test,thermodynamic calculation,and first-principles calculation were performed to evaluate the pitting corrosion of the stainless steel.The initiation of the pitting corrosion by three types of inclusions,including(Mn,Si,Cr,S)O,(Mn,Al,Cr)O,and Al_(2)O_(3)were in-situ observed.After corroding for 880 min,the corrosion index of(Mn,Si,Cr,S)O,(Mn,Al,Cr)O,and Al_(2)O_(3)was 0.38%,0.02%,and 0.00%min−1,respectively.With the increase in aluminum content in the steel,the pitting potential of the stainless steel was 0.131,0.304,and 0.338 V,respectively,indicating that a higher aluminum content in the steel was beneficial to improving the pitting corrosion resistance of the 304 stainless steel.

Development of a DFN-based probabilistic block theory approach for bench face angle design in open pit mining

In open pit mining,uncontrolled block instabilities have serious social,economic and regulatory consequences,such as casualties,disruption of operation and increased regulation difficulties.For this reason,bench face angle,as one of the controlling parameters associated with block instabilities,should be carefully designed for sustainable mining.This study introduces a discrete fracture network(DFN)-based probabilistic block theory approach for the fast design of the bench face angle.A major advantage is the explicit incorporation of discontinuity size and spatial distribution in the procedure of key blocks testing.The proposed approach was applied to a granite mine in China.First,DFN models were generated from a multi-step modeling procedure to simulate the complex structural characteristics of pit slopes.Then,a modified key blocks searching method was applied to the slope faces modeled,and a cumulative probability of failure was obtained for each sector.Finally,a bench face angle was determined commensurate with an acceptable risk level of stability.The simulation results have shown that the number of hazardous traces exposed on the slope face can be significantly reduced when the suggested bench face angle is adopted,indicating an extremely low risk of uncontrolled block instabilities.

Response and assembly of abundant and rare taxa in Zaopei under different combination patterns of Daqu and pit mud:from microbial ecology to Baijiu brewing microecosystem

The quality and aroma of strong-flavor Baijiu are mainly dependent on Daqu,pit mud(PM),and the interaction of both.However,little is known about how their combination patterns affect the microbiome and metabolome of Zaopei,especially the metabolic function of rare taxa.Here,an experiment on industrial size was designed to assess the effects of 6 combinations(3 kinds of Daqu×2 kinds of PM)on the composition and assembly of different taxa,as well as the flavor profile.The results showed that Zaopei's microbiota was composed of a few abundant taxa and enormous rare taxa,and rare bacterial and abundant fungal subcommunities were significantly affected by combination patterns.The assembly processes of abundant/rare taxa and bacterial/fungal communities were distinct,and environmental changes mediated the balance between stochastic and deterministic processes in rare bacteria assembly.Furthermore,specific combination patterns improved the flavor quality of Zaopei by enhancing the interspecies interaction,which was closely related to rare taxa,especially rare bacteria.These findings highlighted that rare bacteria might be the keystone in involving community interaction and maintaining metabolic function,which provided a scientific foundation for better understanding and regulating the brewing microbiota from the viewpoint of microbial ecology.

醋酸靛胭脂混合三明治染色法联合智能分光比色技术结肠镜下Pit pattern分型对结直肠病变的诊断价值

目的 探讨醋酸靛胭脂混合(AIM)三明治染色法联合智能分光比色技术(FICE)结肠镜下Pit pattern分型对结直肠病变的诊断价值。方法 选择2022年6月-2023年10月该院收治的100例结直肠病变患者作为研究对象,共222处病灶;分别采用普通内镜、FICE和AIM三明治染色+FICE进行检查,并记录Pit pattern分型的检出情况、病理学类型;计算不同模式下Pit pattern分型诊断的敏感度、特异度、阳性预测值(PPV)、阴性预测值(NPV)和准确度,采用Kappa检验评估不同模式下Pit pattern分型诊断与病理学检查的一致性,采用受试者操作特征曲线(ROC curve)评估诊断效能。结果 与普通内镜(74.32%)相比,FICE(92.34%)和AIM三明治染色+FICE (97.30%) Pit pattern分型检出与病理结果符合率更高,且AIM三明治染色+FICE高于FICE,差异均有统计学意义(P <0.05);与普通内镜相比,FICE和AIM三明治染色+FICE诊断结直肠肿瘤性病变的准确度更高,且AIM三明治染色+FICE高于FICE,差异均有统计学意义(P <0.05);与普通内镜相比,FICE和AIM三明治染色+FICE诊断早期结直肠癌的准确度更高,差异均有统计学意义(P <0.05);普通内镜、FICE和AIM三明治染色+FICE预测结直肠肿瘤性病变的曲线下面积(AUC)分别为0.815 (95%CI:0.711~0.859)、0.881 (95%CI:0.752~0.904)和0.933 (95%CI:0.793~0.961);普通内镜、FICE和AIM三明治染色+FICE预测早期结直肠癌的AUC分别为0.850 (95%CI:0.720~0.866)、0.938(95%CI:0.764~0.951)和0.947 (95%CI:0.803~0.972);AIM三明治染色+FICE预测结直肠肿瘤性病变和早期结直肠癌的Youden指数最大,分别为0.955和0.968。结论 AIM三明治染色+FICE下Pit pattern分型诊断结直肠肿瘤性病变和早期结直肠癌的准确度较高,可有效提高内镜的诊治质量。

Numerical Analysis of Cold-Formed Thin-Walled Steel Short Columns with Pitting Corrosion during Bridge Construction

Pitting corrosion is harmful during bridge construction,which will lead to uneven roughness of steel surfaces and reduce the thickness of steel.Hence,the effect of pitting corrosion on the mechanical properties of cold-formed thin-walled steel stub columns is studied,and the empirical formulas are established through regression fitting to predict the ultimate load of web and flange under pitting corrosion.In detail,the failure modes and load-displacement curves of specimens with different locations,area ratios,and depths are obtained through a large number of non-linear finite element analysis.As for the specimens with pitting corrosion on the web,all the specimens are subject to local buckling failure,and the failure mode will not change with pitting corrosion,but the failure location will change with pitting corrosion location;the size,location,and area ratio of pitting corrosion have little influence on the ultimate load of cold-formed thin-walled steel short columns,but the loss rate of pitting corrosion section area has a greater impact on the ultimate bearing capacity.As for the specimen with flange pitting corrosion,the location and area ratio of pitting corrosion have less influence on the ultimate load of cold-formed thin-walled steel short columns,and the section area loss rate has greater influence on the ultimate bearing capacity;the impact of web pitting corrosion on the ultimate load is greater than that of flange pitting corrosion under the same condition of pitting corrosion section area.The prediction formulas of limit load which are suitable for pitting corrosion of web and flange are established,which can provide a reference for performance evaluation of corroded cold-formed thin-walled steel.

Coordinated Mining Procedures of Open Pit Mines Based on River Management

This paper primarily concerns the effective coordination of the procedures and methods employed in open pit mining operations under the background of river management.The central objective of this study is to identify a viable approach for ensuring rational and efficient development of open pit mineral resources while simultaneously protecting and restoring the ecological environment of the river.This approach should facilitate the realization of a harmonious symbiosis between mining and river management.The intricate mutual influence relationship between river management and open pit mining is first analyzed in depth,which provides a solid foundation for the subsequent coordination strategy development.In light of the aforementioned considerations,a set of coordination procedures for open pit mining based on river management conditions is proposed.These procedures emphasize the integration of river protection into the overall layout of mining at the planning stage.The implementation of scientific mining schemes,accompanied by rigorous control of the scope and depth of mining operations,has proven to be an effective means of reducing the impact of mining activities on river environments.This approach has also facilitated the achievement of a balance and coordination between mining and river management.

The Importance of Stakeholder Engagement in Progressive Rehabilitation of Large-Scale Open Pit Mines—A Case Study of Lumwana Mine

Mining globally contributes to the growth of many economies of the world. Since its inception, the Zambian mining industry has contributed largely to the country’s economy. The various developments both in technology and knowledge have contributed to the scale at which mining is being done. Challenges in such a setting arise due to the socio-economic and environmental impacts of mining, which create multidimensional problems. The study investigated the importance of engaging stakeholders in progressive rehabilitation programs for large-scale open pit mines, using a case study of the Lumwana Mine and its host community, Manyama. A qualitative approach was used, and data was collected through one-on-one interviews. A combination of convenient and quota sampling was used to engage with host community leaders, professionals and academicians from various fields and institutions. Results showed that most participants had agreed that stakeholder engagement is important for progressive rehabilitation, but the challenge was that the host community and municipal council representatives were not aware of any progressive rehabilitation efforts at Lumwana Mine. This was attributed to a lack of stakeholder engagement and communication of mitigation progress activities by the Lumwana Mine. Results also revealed that the lack of environmental impact assessment regulations to compel companies to involve stakeholders throughout the entire life of the mine other than just at the pre-mining stage led to a lack of compliance and accountability in rehabilitation.

JNET分型与Pit Pattern分型对结直肠肿瘤性病变的诊断价值比较研究

目的:评估并比较窄带成像放大内镜(ME-NBI)下应用JNET分型与Pit pattern分型对结直肠肿瘤性病变的诊断价值,更好地指导内镜下诊治。方法:收集2019.01.01至2021.12.31接受ME-NBI模式结肠镜检查并行病理检查的201例患者,共216处病变,将依据JNET分型与Pit pattern分型的内镜诊断结果与病理分型结果进行比较。结果:在ME-NBI下JNET分型与Pit pattern分型诊断结直肠肿瘤性病变的敏感度、特异度、阳性预测值、阴性预测值分别为100%、20.83%、90.05%、100%、91.20%和98.96%、54.17%、94.53%、86.67%、93.98%,两者在诊断准确性上差异具有统计学意义(χ2 = 99.116, P < 0.001)。同时,在诊断具有内镜治疗指征的早期结直肠癌时JNET分型、Pit pattern分型的敏感度、特异度、阳性预测值、阴性预测值分别为71.43%、76.05%、46.67%、90.07%、75.00%和81.63%、93.41%、78.43%、94.55%、90.74%,两者在诊断准确性上差异具有统计学意义(χ2 = 14.400, P < 0.001)。结论:ME-NBI下先采用JNET分型可发现更多的肿瘤性病变,再利用Pit pattern提高诊断肿瘤性病变的准确性,提升内镜诊治质量。

Effect of surface damage induced by cavitation erosion on pitting and passive behaviors of 304L stainless steel

The corrosion behavior of 304L stainless steel(SS)in 3.5wt%NaCl solution after different cavitation erosion(CE)times was mainly evaluated using electrochemical noise and potentiostatic polarization techniques.It was found that the antagonism effect resulting in the passivation and depassivation of 304L SS had significant distinctions at different CE periods.The passive behavior was predominant during the incubation period of CE where the metastable pitting initiated at the surface of 304L SS.Over the rising period of CE,the 304L SS experienced a transition from passivation to depassivation,leading to the massive growth of metastable pitting and stable pitting.The depassivation of304L SS was found to be dominant at the stable period of CE where serious localized corrosion occurred.

基层内镜医师pit pattern分型在线培训效果观察

目的:观察新疆兵团基层内镜医师pit pattern分型的在线培训效果。方法:选取2021-2022年新疆兵团基层医院的内镜医师81名,将肠镜操作量≥3000例医师分为专家组39名,非专家组42名。对所有医师进行pit pattern分型在线培训和培训前、后测试。比较培训前后医师判断结直肠息肉pit pattern分型的准确率,并分析判断结果与正确结果的一致性。结果:对兵团基层内镜医师的pit pattern分型在线培训取得了满意的效果。培训前、后测试表现:(1)所有医师及专家组、非专家组医师培训后判断总体息肉pit pattern分型的准确率明显高于培训前(P<0.001),所有医师培训后判断肿瘤性、非肿瘤性息肉pit pattern分型的准确率高于培训前(P<0.001),且所有医师培训后判断息肉pit pattern分型的每一分型的准确率也高于培训前(P<0.001)。(2)相较于培训前,培训后所有医师及专家组、非专家组医师息肉pit pattern分型判断结果与正确结果的Kappa值有提高,且培训后所有医师息肉性质判断结果与正确结果的Kappa值也有提高。结论:在线培训的方式能够提升基层内镜医师使用pit pattern分型辨别结直肠息肉性质的能力。

Gear Pitting Measurement by Multi-Scale Splicing Attention U-Net

The judgment of gear failure is based on the pitting area ratio of gear.Traditional gear pitting calculation method mainly rely on manual visual inspection.This method is greatly affected by human factors,and is greatly affected by the working experience,training degree and fatigue degree of the detection personnel,so the detection results may be biased.The non-contact computer vision measurement can carry out non-destructive testing and monitoring under the working condition of the machine,and has high detection accuracy.To improve the measurement accuracy of gear pitting,a novel multi-scale splicing attention U-Net(MSSA U-Net)is explored in this study.An image splicing module is first proposed for concatenating the output feature maps of multiple convolutional layers into a splicing feature map with more semantic information.Then,an attention module is applied to select the key features of the splicing feature map.Given that MSSA U-Net adequately uses multi-scale semantic features,it has better segmentation performance on irregular small objects than U-Net and attention U-Net.On the basis of the designed visual detection platform and MSSA U-Net,a methodology for measuring the area ratio of gear pitting is proposed.With three datasets,experimental results show that MSSA U-Net is superior to existing typical image segmentation methods and can accurately segment different levels of pitting due to its strong segmentation ability.Therefore,the proposed methodology can be effectively applied in measuring the pitting area ratio and determining the level of gear pitting.

Construction Technology and Safety Risk Control Measures of Deep Foundation Pit Excavation

Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.

Compressive Strength of Tubular Members with Combined Pitting Corrosion and Crack Damage

Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.

Geopolymer-based modification of blasting sealing materials and optimization of blasting block size in coal seams of open pit mines

This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages.