A state-of-the-art review of automated extraction of rock mass discontinuity characteristics using three-dimensional surface models

In the last two decades,significant research has been conducted in the field of automated extraction of rock mass discontinuity characteristics from three-dimensional(3D)models.This provides several methodologies for acquiring discontinuity measurements from 3D models,such as point clouds generated using laser scanning or photogrammetry.However,even with numerous automated and semiautomated methods presented in the literature,there is not one single method that can automatically characterize discontinuities accurately in a minimum of time.In this paper,we critically review all the existing methods proposed in the literature for the extraction of discontinuity characteristics such as joint sets and orientations,persistence,joint spacing,roughness and block size using point clouds,digital elevation maps,or meshes.As a result of this review,we identify the strengths and drawbacks of each method used for extracting those characteristics.We found that the approaches based on voxels and region growing are superior in extracting joint planes from 3D point clouds.Normal tensor voting with trace growth algorithm is a robust method for measuring joint trace length from 3D meshes.Spacing is estimated by calculating the perpendicular distance between joint planes.Several independent roughness indices are presented to quantify roughness from 3D surface models,but there is a need to incorporate these indices into automated methodologies.There is a lack of efficient algorithms for direct computation of block size from 3D rock mass surface models.

Strengthening the three-dimensional comprehensive observation system of multi-layer interaction on the Tibetan Plateau to cope with the warming and wetting trend

Changes in the water cycle on the Tibetan Plateau(TP)have a significant impact on local agricultural production and livelihoods and its downstream regions.Against the background of widely reported warming and wetting,the hydrological cycle has accelerated and the likelihood of extreme weather events and natural disasters occurring(i.e.,snowstorms,floods,landslides,mudslides,and ice avalanches)has also intensified,especially in the highelevation mountainous regions.Thus,an accurate estimation of the intensity and variation of each component of the water cycle is an urgent scientific question for the assessment of plateau environmental changes.Following the transformation and movement of water between the atmosphere,biosphere and hydrosphere,the authors highlight the urgent need to strengthen the three-dimensional comprehensive observation system(including the eddy covariance system;planetary boundary layer tower;profile measurements of temperature,humidity,and wind by microwave radiometers,wind profiler,and radiosonde system;and cloud and precipitation radars)in the TP region and propose a practical implementation plan.The construction of such a three-dimensional observation system is expected to promote the study of environmental changes and natural hazards prevention.

Solution and simulation algorithm of microseismic events location to three-dimensional model by comprehensive location method based on Matlab

The essential for microseismic monitoring is fast and accurate calculation of seismic wave source location. The precision of most traditional microseismic monitoring processes of mines, using TDOA location method in two-dimensional space to position the microseismic events, as well as the accuracy of positioning microseismic events, may be reduced by the two-dimensional model and simple method, and ill-conditioned equations produced by TDOA location method will increase the positioning error. This article, based on inversion theory, studies the mathematical model of TDOA location method, polariza- tion analysis location method, and comprehensive difference location method of adding angle factor in the traditional TDOA location method. The feasibility of three methods is verified by numerical simulation and analysis of the positioning error of them. The results show that the comprehensive location method of adding angle difference has strong positioning stability and high positioning accuracy, and it may reduce the impact effectively about ill-conditioned equations to positioning results. Comprehensive location method with the data of actual measure may get better positioning results.

Optimization of Extraction Process for Longan(Dimocarpus longan Lour.)Leaves Using Multi-indicator Comprehensive Evaluation Method

[Objectives]This study aimed to optimize the extraction process of longan(Dimocarpus longan Lour.)leaves by multi-indicator comprehensive evaluation method.[Methods]The contents of gallic acid ethyl ester,astragalin,quercetin,luteolin and kaempferol in longan leaves were determined simultaneously by HPLC.Using the multi-indicator comprehensive evaluation method,the methanol concentration,solid to liquid ratio and extraction time for extraction of longan leaves were optimized by orthogonal test.[Results]The optimal extraction process of longan leaves are as follows:methanol concentration of 100%,solid to liquid ratio of 1∶5,and extraction time of 50 min.[Conclusions]The optimized process is simple and feasible,and it can be used to determine the contents of different ingredients in longan leaves.

Lithium extraction from hard rock lithium ores(spodumene,lepidolite,zinnwaldite,petalite):Technology,resources,environment and cost

Lithium production in China mainly depends on hard rock lithium ores,which has a defect in resources,environment,and economy compared with extracting lithium from brine.This paper focuses on the research progress of extracting lithium from spodumene,lepidolite,petalite,and zinnwaldite by acid,alkali,salt roasting,and chlorination methods,and analyzes the resource intensity,environmental impact,and production cost of industrial lithium extraction from spodumene and lepidolite.It is found that the sulfuric acid method has a high lithium recovery rate,but with a complicated process and high energy consumption;alkali and chlorination methods can directly react with lithium ores,reducing energy consumption,but need to optimize reaction conditions and safety of equipment and operation;the salt roasting method has large material flux and high energy consumption,so require adjustment of sulfate ratio to increase the lithium yield and reduce production cost.Compared with extracting lithium from brine,extracting lithium from ores,calcination,roasting,purity,and other processes consume more resources and energy;and its environmental impact mainly comes from the pollutants discharged by fossil energy,9.3-60.4 times that of lithium extracted from brine.The processing cost of lithium extraction from lepidolite by sulfate roasting method is higher than that from spodumene by sulfuric acid due to the consumption of high-value sulfate.However,the production costs of both are mainly affected by the price of lithium ores,which is less competitive than that of extracting lithium from brine.Thus,the process of extracting lithium from ores should develop appropriate technology,shorten the process flow,save resources and energy,and increase the recovery rate of related elements to reduce environmental impact and improve the added value of by-products and the economy of the process.

Integration system research and development for three-dimensional laser scanning information visualization in goaf

An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.

Identification and Characterization of Sulfur Compounds in Straight-Run Diesel Using Comprehensive Two-Dimensional GC Coupled with TOF MS

The solid-phase extraction using Pd-Al2O3 as the stationary phase was employed to pre-separate the sulfur compounds in straight-run diesel. The isolating effect was evaluated quantitatively by gas chromatography with a sulfur chemiluminescence detector to harvest a satisfactory result. The identification of the structure of sulfur compounds by comprehensive two-dimensional gas chromatography coupled with the time-of-flight mass spectrometry indicated that cyclo-sulfides, benzothiophenes, dibenzothiophenes, dihydro-benzothiophenes and tetrahydro-dibenzothiophenes were included in straightrun diesel obtained from the Arab medium crude(AM). A total of 259 individual compounds were detected and their molecular structures were identified. The analytical method was approved as an effective way to characterize the composition of sulfur compounds, which reduced the interference of other compounds, facilitated the data presentation and provided more detailed information about molecular composition of sulfur compounds.

Research Progress of Value, Extraction and Applicationof Silkworm Chrysalis Protein

Silkworm chrysalis protein is a high quality pure natural complete animal protein with high utilization value, and it has been widely usedin many industries in recent years. The nutrition, health care and medicinal value of silkworm chrysalis protein, the degreasing, deodorization anddecoloration extraction process, and its application in food, medicine, feed, etc. are summarized, in order to provide the reference for further development and industrial production of silkworm chrysalis protein.

Inhibition of mammalian target of rapamycin induces phenotypic reversion in three-dimensional cultures of malignant breast epithelial cells

Inhibition of mammalian target of rapamycin (m- TOR) is a potential method for cancer treatment. Effects of rapamycin (RAP) on the reversion of malignant breast epithelial cells were investigated on three-dimensional (3D) basement membrane extract (BME) cultures. Through continuous exposure to 20 nM of RAP, cell colony size was significantly reduced in 3D BME cultures of malignant breast epithelial cells, while normal cell colony size appeared unaffected. In unfixed 3D BME cultures of normal and RAP-treated malignant breast epithelial cells, the presence of luminal cell death was confirmed by ethidium bromide and propidium iodide labeling. Increased structural organization was observed by im- munofluorescence staining of F-actin and β-catenin in RAP-treated malignant breast epithelial cells. In monolayer cultures of normal and malignant breast epithelial cells, continuous exposure to 20 nM of RAP increased caspase 3/7 activity and decreased proliferation. Reverse transcriptase polymerase ch- ain reaction (RT-PCR) array analysis indicated a fold increase in the expression of a number of proteins related to polarity, cell-cell adhesion, and cell-matrix adhesion in the presence of RAP. Our data showed that phenotypic reversion of malignancy can be ach- ieved through RAP exposure on 3D BME cultures. This 3D BME culture system will provide correct microenvironments for observing the effects of other mTOR inhibitors on phenotypic reversion of malignant breast epithelial cells.

气田水锂、溴资源定量计算方法和前景展望——以W气田震旦系气藏为例

目的鉴于国内部分气田地层水中丰富的锂、溴资源,为明确气田水开发的综合利用价值,定量计算和评估锂、溴总体资源量。方法基于地质分析法,提出一种定量计算已开发气田地层水(以下简称气田水)中锂、溴资源量的新方法,并结合行业内提锂、提溴工艺,计算气田水可提取的碳酸锂、溴素等工业原料资源量。结果①W气田震旦系气藏为具有统一气水界面的底水气藏,气田水总地质储量为29.92×10^(8)m^(3);②采用矿化度约束权衡法、井点面积权衡法、等值线面积权衡法分别计算气田水锂元素、溴元素的平均含量,最终确定气田水中锂元素和溴元素的平均质量浓度分别为114.8 mg/L和181.7 mg/L;③综合水体储量和锂、溴元素含量,定量计算气田水锂元素总量为34.35×10^(4)t,溴元素总量为54.37×10^(4)t;④基于气田水锂、溴元素含量,预测可提取工业产品碳酸锂146.19×10^(4)t,溴素144.19×10^(4)t。结论基于已开发气田气藏特点和气田水开发综合利用行业新热点,定量评估锂、溴资源量,结合提锂、溴工艺技术,形成气田水开发综合利用新链条,为国内外同类型气田的有效开发和新能源利用提供借鉴。

甘肃产不同品种松针的抗氧化活性研究

以甘肃产白皮松、雪松、油松、落叶松、樟子松和华山松6个树种的松针为研究对象,采用DPPH法、ABTS法和铜离子还原能力测定其不同浓度乙醇提取物的体外抗氧化活性,并采用熵值法综合评价遴选出抗氧化活性强的松针资源,为松针的进一步开发利用提供参考。研究表明:采用不同浓度乙醇提取时,40%乙醇提取物的抗氧化活性最好;不同品种松针中,雪松松针的抗氧化活性最好,其中天水产雪松松针40%乙醇提取物的评分最高达99.52%,表明其可以作为进一步研究松针抗衰老研究的资源。

面向机器阅读理解的边界感知方法

针对现有的基于预训练语言模型的答案获取方法存在预测边界不够准确的问题,提出一种面向片段抽取式机器阅读理解(MRC)的边界感知方法。首先,在问题输入阶段引入特殊字符标记问题边界,通过增强问题语义信息的方式实现对问题边界的感知;其次,在答案预测阶段,构建答案边界回归器,实现感知的问题边界语义信息与输出的预测答案边界语义信息的语义交互;最后,通过交互后的语义信息进一步调整存在偏差的预测答案边界,实现对预测答案的校准。实验结果表明,与SpanBERT(Span-based Bidirectional Encoder Representation from Transformers)相比,该方法在公共数据集SQuAD(Stanford Question Answering Dataset)1.1上的F1值提升了0.2个百分点、精确匹配(EM)值提升了0.9个百分点;在HotpotQA(Hotpot Question Answering)数据集上的F1值和EM值都提升了0.7个百分点;在NewsQA(News Question Answering)数据集上的F1值提升了2.8个百分点、EM值提升了3.3个百分点。可见,该方法能有效增强对问题边界信息的感知并且实现对预测答案边界的校准,有利于更好地理解和分析文本数据,在智能问答、智能客服等领域的应用中提高系统的准确性。

面向小样本抽取式问答的多标签语义校准方法

小样本抽取式问答任务旨在利用文章给定的上下文片段,抽取出真实的答案片段。其基线模型采用的方法只针对跨度进行学习,缺乏对全局语义信息的利用,在含有多组不同重复跨度的实例中存在着理解偏差等问题。为了解决上述问题,该文利用不同层级的语义提出了一种面向小样本抽取式问答任务的多标签语义校准方法。采用包含全局语义信息的头标签和基线模型中的特殊字符构成多标签进行语义融合,并利用语义融合门来控制全局信息流的引入,将全局语义信息融合到特殊字符的语义信息中。然后,利用语义筛选门对新融入的全局语义信息和该特殊字符的原有语义信息进行保留与更替,实现对标签偏差语义的校准。在8个小样本抽取式问答数据集中的56组实验结果表明:该方法在评价指标F1值上均明显优于基线模型,证明了所提方法的有效性和先进性。

栾川县尾矿综合利用研究进展

栾川县矿产资源丰富,尾矿库较多。结合栾川县尾矿库调查结果,综述钼钨、铅锌、金和铁等类型的尾矿综合利用研究进展,并提出尾矿综合利用的优化策略,为矿山固体废弃物的资源化、减量化与无害化处置提供技术指导。目前,尾矿综合利用方式主要有3种,即有价金属元素提取、有价非金属元素提取和尾矿建材化利用。未来,要加大科研投入,开发新型尾矿综合利用工艺;推进尾矿原位回填,修复区域生态环境;强化梯级利用,实现尾矿全部消纳。

基于层次分析法的崂山旅游文创设计

基于层次分析法,建立一种旅游文创产品设计流程,并将崂山旅游文化融入文创产品的设计中,发挥崂山当地文化特色,深入挖掘崂山旅游文化内涵,为旅游文创产品设计提供多元化设计思路。首先,从线上线下两方面调研崂山旅游文化,构建文化筛选评价模型并以此为参考,筛选合适的崂山旅游文化要素,然后将筛选出的文化要素用因子提取的方法进行图案提炼,并将其运用到文创产品的设计中,最后,运用模糊综合评价法对设计出的方案进行评价。建立旅游文创设计流程,完成崂山旅游文创产品设计。在崂山旅游文创产品设计中,通过运用AHP层次分析法,初步构建满足旅游文创开发的设计需要;能够更加客观完善地选取崂山道教旅游文化元素,结合当地文旅特色完成文创产品的创作,力求传播当地文化特色,是文旅产品设计的新思路。

天然产物提取技术的实验设计与优化

针对我校应用化学专业实验部分教学内容单一性较强,授课过程学生参与的主动性较差,不能有效践行以学生为本的教育理念,开发了从西红柿、菠菜、橙皮、红辣椒等天然产物中提取有用成分的综合设计性实验技术。学生可以自由选择天然产物,组成2~3人团队,通过文献查阅、实验方案设计、有用成分的提取与分离、产品检测、数据分析等教学环节,培养学生运用应用化学专业的理论知识来解决生活实际问题的能力。将生活实际转化为综合性设计性实验内容,强化专业实验技能培养,增强应化专业学生实践能力,从而满足工程教育专业认证背景下对于人才培养的要求。

提钒尾矿综合回收利用研究现状

从有价组分回收、新型功能材料合成和多用途建筑材料制备三个方面阐述了目前提钒尾矿资源的综合回收利用途径,可为提钒尾矿综合回收技术应用提供参考。

面向抽取式阅读理解的数据增强研究

在抽取式阅读理解中,语言模型在训练数据较少情况下的表现不佳,使用EDA方法虽能有效增加数据量,但会造成数据中语义信息损失,导致模型训练效果不佳。针对上述问题,结合EDA提出面向少样本情况下抽取式阅读理解的数据增强方法,在保留数据中问题正确答案的前提下对数据进行单词级和句子级数据增强。同时,为了对句子语义影响最小的单词进行数据增强,使用基于语义相似度的数据增强方法(DASS)计算句子中某一个单词删除前后的语义相似度,以判断该单词对句子语义的影响,选择对语义影响最小的单词进行数据增强,提升训练数据质量,以提升语言模型鲁棒性。在HotpotQA数据集上的实验结果表明,DASS可以解决模型在样本数量较少时获取语义信息不足的问题,在样本数量为500时,模型预测的F1值提升23.94%,在对整个数据集使用该方法时,模型预测的F1值提升了2.54%。

多指标综合评分法结合Box-Behnken响应面法优选栀子茯苓压片糖果的提取工艺

以提取液中栀子苷含量及干膏率作为考察指标,在单因素试验基础上采用直接回流提取法、多指标综合评分法结合Box-Behnken响应面法考察了乙醇浓度、提取时间和料液比3个因素对提取工艺的影响。结果表明,制剂的最佳提取工艺为乙醇浓度75%,提取时间120 min,料液比17倍,栀子苷平均含量为3.17%,平均干膏率为11.33%,综合评分平均值为98.30(n=3,RSD=0.18%)。该工艺合理可行,有效成分提取率高,适合大规模生产。

锂辉石提锂工艺现状及晶型转化研究进展

矿石提锂由于反应效率高、生产周期短,是制备高端锂材的主要方法之一。锂辉石因其氧化锂品位高是矿石提锂的主要来源。开发高效锂辉石提锂工艺对于保障锂行业可持续发展具有重要意义。通过对典型的锂辉石提锂工艺,包括硫酸法、石灰石烧结法、硫酸盐法、氯化焙烧法、碱性压煮法和氟化学法等研究现状进行阐述,充分探讨各提锂工艺的反应原理、工艺参数、反应效率等,客观分析总结现有工艺的优缺点,并对锂辉石提锂工艺的改进进行总结展望。此外,对提锂过程中涉及的晶型转化的研究进展进行分析,重点对相变过程中γ相的生成及对相变路径的影响因素进行系统讨论,为指导α锂辉石短流程甚至无相变制备锂盐产品提供指导。