炼化企业低温热系统优化技术及应用

石油炼化企业低温热系统有着巨大的节能潜力,但并没有得到企业足够的重视。针对企业低温热系统存在建设、管理分散,运行经济性低等实际问题,为了满足企业降低成本、节能减耗的目的,深入剖析了现今炼化企业低温热系统优化的关键问题,提出了炼化企业低温热系统的优化技术,建立了低温热系统的全流程优化模型,开展了低温热系统的操作优化与改造优化。应用结果表明,该技术节能降碳效果显著,而且大大提升了企业低温热系统的数字化水平。

Variation in the surface heat flux on the north and south slopes of Mount Qomolangma

The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two slopes.In this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both slopes.The inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation outcomes.The model results are validated using observational data.The RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),respectively.The net radiation flux is greater on the south slope and exhibits a rapid decline from summer to autumn.Due to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the monsoon.The south slope experiences the highest latent heat flux in summer.The dominant flux on the north slope is sensible heat,while it is latent heat on the south slope.The seasonal variations in the ground heat flux are more pronounced on the south slope than on the north slope.Except in summer,the ground heat flux on the north slope surpasses that on the south slope.

基于遥感影像的土地利用监测及城市扩张分析

对Landsat遥感影像进行数据预处理,其次采用随机森林分类方法分析2001年、2011年和2021年3期的土地利用情况,对近年来哈尔滨市的土地利用进行时空监测,同时对建设用地扩张情况进行分析,研究结果表明:研究区建设用地面积在20年的时间里,城市规模迅速扩张,建设用地面积增加到约560.47 km^(2);从2001年到2011年,水体和其他用地面积变化不大,耕地变化较大,从2011年到2021年各土地利用类型变化均较大。哈尔滨市城市重心在不断发生着变化,表现出由北—西北—西南的变化过程。城市建设用地主体呈现在城市中心集聚,其他区域建设用地均匀分布的态势。

Design of Compliant Straight-line Mechanisms Using Flexural Joints

Straight-line compliant mechanisms are important building blocks to design a linear-motion stage, which is very useful in precision applications. However, only a few configurations of straight-line compliant mechanisms are applicable. To construct more kinds of them, an approach to design large-displacement straight-line flexural mechanisms with rotational flexural joints is proposed, which is based on a viewpoint that the straight-line motion is regarded as a compromise of rigid and compliant parasitic motion of a rotational flexural joint. An analytical design method based on the Taylor series expansion is proposed to quickly obtain an approximate solution. To illustrate and verify the proposed method, two kinds of flexural joints, cross-axis hinge and leaf-type isosceles-trapezoidal flexural（LITF） pivot are used to reconstruct straight-line flexural mechanisms. Their performances are obtained by analytic and FEA method respectively. The comparisons of the results show the accuracy of the approach. Both examples show that the proposed approach can convert a large-deflection flexural joint into approximate straight-line mechanism with a high linearity that is higher than 5 000 within 5 man displacement. This can lead to a new way to design, analyze or optimize straight-line flexure mechanisms.

Effects of surface heating on precipitation over the Tibetan Plateau and its eastern margin

The high terrain of the Tibetan Plateau(TP)has a very important impact on the weather and climate of China,East Asia,South Asia,and even the Northern Hemisphere.However,in recent years,the reasons for the decrease in precipitation in the southeastern edge of the plateau have resulted in cutting-edge research regarding the impact of the TP and its surrounding areas on downstream weather and climate.In this study,the spatial and temporal distribution of surface heat flux and precipitation were analyzed from 1998 to 2022,and the possible mechanism of the decrease of precipitation in the eastern edge of the plateau is explored.The main conclusions are as follows:The annual average sensible heat flux in the TP and its east side is positive,with an average of 33.73 W/m^(2).The annual average latent heat flux is positive,with an average of 42.71 W/m^(2).Precipitation has a similar annual average and seasonal distribution,with modest amounts in the northwest and substantial amounts in the southeast.The average annual accumulated precipitation is 670.69 mm.The first mode of the Empirical Orthogonal Function(EOF)shows that sensible heat flux decreases first,then increases,and then finally decreases during 1998–2022.The modes show the opposite trend in middle part of the plateau.The latent heat flux initially decreases,then increases,and finally decreases in the western plateau and near Sichuan Basin.The mode,however,displays the opposite tendency throughout the rest of the region.The precipitation in the north and south sides of the plateau has decreased since 2013,which is consistent with the changing trend of sensible heat flux.In the rest of the region,the change trend is not obvious.The sensible heat of the main body of the plateau and its east side and Sichuan Basin is negatively correlated with precipitation,that is,when sensible heat flux of the main body of the plateau and its east side and Sichuan Basin is more(less),local precipitation is less(more).The latent heat of the main body of the plateau and its east side,Sichuan Basin is positively correlated with precipitation,indicating that when latent heat flux of the main body of the plateau and its east side,Sichuan Basin is more(less),local precipitation is more(less).

大比例尺数据转换为GIS入库数据的技术研究

面对大比例尺数据比例尺多样、格式多样、数学基础多样的特点,结合天地图应用的需求,设计转换标准数据库。针对转换标准库的转换内容,制定大比例尺数据转换为GIS入库数据的技术流程,详细描述入库转换的基本原则以及入库转换的具体步骤,分析大比例尺数据转换入库数据尚存的问题,形成大比例尺数据转换入库数据的整体技术方法。

A molecular toolkit to boost functional genomic studies in transformation-recalcitrant vegetable legumes

Dear Editor Legumes,the second-largest family of crops,contribute over one-third of human dietary proteins.Soybean(Glycine max L.),common bean(Phaseolus vulgaris L.),pea(Pisum sativum L.),and cowpea(Vigna unguiculata L.)are among the most widely culti-vated crop legumes for grain and vegetable and are essential for food security globally.

Understanding water conservation vs. prof ligation traits in vegetable legumes through a physio-transcriptomic-functional approach

Abstract Vegetable soybean and cowpea are related warm-season legumes showing contrasting leaf water use behaviors under similar root drought stresses,whose mechanisms are not well understood.Here we conducted an integrative phenomic-transcriptomic study on the two crops grown in a feedback irrigation system that enabled precise control of soil water contents.Continuous transpiration rate monitoring demonstrated that cowpea used water more conservatively under earlier soil drought stages,but tended to maintain higher transpiration under prolonged drought.Interestingly,we observed a soybean-specific transpiration rate increase accompanied by phase shift under moderate soil drought.Time-series transcriptomic analysis suggested a dehydration avoidance mechanism of cowpea at early soil drought stage,in which the VuHAI3 and VuTIP2;3 genes were suggested to be involved.Multifactorial gene clustering analysis revealed different responsiveness of genes to drought,time of day and their interactions between the two crops,which involved species-dependent regulation of the circadian clock genes.Gene network analysis identified two co-expression modules each associated with transpiration rate in cowpea and soybean,including a pair of negatively correlated modules between species.Module hub genes,including the ABA-degrading gene GmCYP707A4 and the trehalose-phosphatase/synthase gene VuTPS9 were identified.Intermodular network analysis revealed putative co-players of the hub genes.Transgenic analyses verified the role of VuTPS9 in regulating transpiration rate under osmotic stresses.These findings propose that species-specific transcriptomic reprograming in leaves of the two crops suffering similar soil drought was not only a result of the different drought resistance level,but a cause of it.

一种飞船用并联式太阳电池阵指向机构设计与分析

为满足太阳电池阵在飞船上大范围指向要求,实现光照效率最大化,设计了一种用于飞船等航天器的新型并联式太阳电池阵指向机构,采用规则对称的模块化设计形式,具有工作空间大、可靠性高等特点。对新型并联式太阳电池阵指向机构进行了运动学正逆解计算,运用极限边界搜索法在MATLAB中计算了工作空间,建立了基于ADAMS的虚拟样机模型,并对其逆解进行了验证,以工程可实现性为原则,得出了多个逆解的筛选原则,为控制系统的参数筛选提供了依据。通过对并联机构的冗余特性进行分析,证明了在某一驱动组件卡死时,其仍具备较大的工作空间。该并联式指向机构还可用于航天器矢量推进器、天线指向等空间领域。

基于增强CT影像组学模型鉴别肾透明细胞癌与非透明细胞癌

目的建立基于增强CT的影像组学模型,评估其鉴别肾透明细胞癌(ccRCC)与非透明细胞癌(non-ccRCC)的应用价值。方法将147例ccRCC及32例non-ccRCC患者随机分为训练集125例和测试集54例。将所有患者的增强CT资料导入ITK-SNAP软件,手动勾画ROI,获得16个特征,分别建立基于特征的随机森林(RF)模型和逻辑回归(LR)模型,采用ROC曲线观察模型对ccRCC的诊断效能。结果训练集RF模型诊断ccRCC的AUC为0.96(P<0.05),特异度为1.00,敏感度0.83;LR模型诊断ccRCC的AUC为0.96(P<0.05),特异度为1.00,敏感度为0.83。测试集RF模型诊断ccRCC的AUC为0.96(P<0.05),特异度为1.00,敏感度为0.89;LR模型诊断ccRCC的AUC为0.88(P<0.05),特异度为0.90,敏感度为0.77。结论基于增强CT影像组学模型可用于鉴别ccRCC与non-ccRCC;RF模型诊断价值较LR模型更高。

单壁碳纳米管对纳米通道中离子电流影响的机制

[目的]对纳米通道中离子电流调制机制的理解,是发展纳米农业检测传感器的关键。[方法]采用分子动力学模拟的方法,研究受限纳米通道中单壁碳纳米管的荷电量对离子电流阻塞的影响。[结果]仿真结果表明:电中性的单壁碳纳米管进入通道中时产生的阻塞电流始终小于基准电流。在碳纳米管带电荷且荷电量增加的情况下,当溶液浓度较低时,阻塞电流大于基准电流;当溶液浓度较高时,阻塞电流小于基准电流,出现电流交叉现象。[结论]单壁碳纳米管过孔时其体积占位对电渗流的影响以及其本身荷电量对纳米通道中离子浓度的影响相互竞争,共同决定着纳米通道中的离子电流。

An fMRI Study of Words Processing in Chinese Language

Using the blood oxygen levels dependent technology of magnetic resonance imaging (BLOD-fMRI), we aimed to explore the brain activation after visual stimulation by Chinese words. In the current study, 24 healthy volunteers (12 males, 12 females, right-handed, mean age 26 ± 2 years) were prospectively included. The event related design was used in the current fMRI study when participants silently read all words appearing in the middle of the screen. Images were processed with Statistical Parametric Mapping 8 (SPM8) software, by using a general linear model (GLM). Group activations were extracted from the 2nd level group analysis with a threshold of p < 0.001, and it was shown that the main activated areas by silent reading tasks were regions involved in brain semantic processing, including middle temporal gyrus, fusiform gyrus, supplementary motor area, inferior frontal gyrus, cingulate gyrus, superior parietal lobule and inferior parietal lobule. It was also learnt that superior parietal lobule and middle temporal gyrus are related with semantic understanding, lenticular nucleus are related with semantic processing. This means, in addition to the cerebral cortex, subcortical nuclei is also very important to the processing of words in Chinese language.

我国一流大学建设高校硕士研究生入学机会平等性测度及表现

对42所一流大学建设高校8541个研究生招生专业进行分析,发现学位类型、学习方式和学科门类三个维度下的不平等现象以不同形态影响着我国硕士研究生入学机会平等的实现进程。总体而言,入学机会不平等主要源于学术学位、全日制和自然科学招生专业,其中,轻度不平等高校倾向招收推免生,而不平等度较高院校则较为歧视同等学力考生,其原因可归结为基于考生出身的制度性偏倚或歧视。故此建议一流大学建设高校应首先对学术学位、全日制和自然科学中的不平等招生专业进行“定点清除”,然后排查其他维度下的不平等专业并对其不合规、不合理条件予以修正,最后秉承机会平等的人才观和制度观设计“不偏不倚式”的研究生招生制度。

基于主动噪声控制技术改善车内声品质

为达到改善某款SUV匀速工况下车内声品质的目的,以驾驶员右耳旁的稳态噪声为研究对象,建立GA-BP声品质预测模型,对声品质客观参量和主观烦恼度进行一元线性回归,选取与主观烦恼度显著相关的响度和粗糙度作为控制目标,利用Zwicker计算模型对响度进行分析,利用小波变换对粗糙度进行分析,根据分析结果确定最优控制频带,并设计基于FELMS算法的主动噪声控制系统对样本噪声进行主动控制。仿真结果表明,控制后噪声的响度、粗糙度分别降低了33.5%、23.1%,烦恼度等级下降了2.76个等级,车内声品质得到大幅改善。

冲击波动态传播特性对激光喷丸残余应力场的影响

以TC4钛合金为研究对象,基于Johnson-Cook本构模型,分析了高应变率效应对激光喷丸过程中塑性波波速的影响。通过三维有限元方法模拟了不同作用参数激光喷丸诱导冲击波的传播过程,探讨了多次激光喷丸作用后残余压应力饱和现象的产生机理及利用该效应获得均匀表面残余压应力的方法。结果表明:高应变率效应对激光喷丸作用过程中塑性波速度有显著影响,塑性波的速度与所产生的塑性应变呈反比关系。功率密度越大,初始产生的塑性应变越大,塑性波速度越小,冲击波能量衰减越快,冲击波压力幅值降低越快;相同激光喷丸功率密度,随着作用次数的增加,产生的塑性应变逐渐减小,塑性波速度增大,冲击波压力衰减变缓,使激光喷丸诱导的残余压应力逐渐增大;作用次数达到3~4次时,衰减过程基本相似,诱导的残余压应力增幅不大,作用效果基本达到饱和。利用多次激光喷丸作用产生的饱和效应,当激光光斑搭接率超过50%时,即可使搭接区域作用次数达到3次及以上,使激光喷丸作用效果达到饱和,可获得均匀的表面残余压应力。

基于改进响应面模型的悬架K&C特性优化

悬架运动学和弹性运动学特性是影响操纵稳定性的重要因素。为提高操纵稳定性,基于ADAMS/Car建立某车型前麦弗逊悬架模型,并进行K&C特性仿真分析。在ADAMS/Insight中计算硬点坐标对K&C特性的灵敏度。利用切比雪夫多项式零点插值技术改进响应面模型,并采用该模型描述悬架K&C特性变动范围与硬点坐标之间的关系,针对该模型采用双层嵌套的改进非支配排序遗传算法和粒子群算法进行多目标优化,结果表明,优化后的悬架K&C特性的变动范围均有不同程度的减小,汽车操纵稳定性得到了提高。

基于InSAR技术在山地区域DEM提取及精度评定

利用InSAR技术对四景ENVISAT-ASAR雷达数据进行DEM提取。简述了InSAR测高的原理,总结了SAR数据的处理方法。获取了两组研究区域DEM成果,经精度评定,成果能够满足1∶50 000比例尺DEM产品的精度要求。同时,实验证明InSAR技术可以快速地获取大面积DEM。

基于灰色系统GM(1,1)千将坪滑坡变形监测分析

滑坡在世界范围内广泛分布,我国地域辽阔,有着较为复杂的地理环境,是世界上受灾害影响十分严重的国家之一。2003年7月13日在湖北省秭归县发生千将坪滑坡,由于千将坪滑坡是发生在三峡库区蓄水达到135 m后,因此,受到国内外众多研究机构及学者的关注。本文主要利用千将坪滑坡体上安置的大量GPS监测点,依据监测点在滑坡体上的展布情况及数据完整程度选取特征点进行研究,通过编程建立千将坪滑坡灰色系统GM(1,1)位移预测模型,综合分析预测滑坡变形情况并进行精度评价。

京津冀互联网公共数字文化服务差异比较分析

公共数字文化服务是公共文化服务的重要组成部分,是公共文化服务机构依托"互联网+"开展的重要网络服务手段。近年来,京津冀三地在公共数字文化建设上取得了不少成绩,初步建成了依托互联网的优秀传统文化资源、文艺辅导等多种资源,并依托网站、APP、微博、微信等多种渠道面向社会公众提供数字公共文化服务。文章利用互联网公开的统计工具,就京津冀三地资源服务、功能服务、平台建设等方面进行了对比分析,并在一体化发展的框架下提出相应对策建议。

Cloning, overexpression, and characterization of a novel organic solvent-tolerant lipase from Paenibacillus pasadenensis CS0611

We found a novel lipase gene in the Paenibacillus pasadenensis CS0611 strain.The lipase gene sequence was cloned into the pET-28a expression vector to construct a recombinant lipase protein containing 6×His tags at the C-and N-termini,respectively.High-level expression of the lipase in E.coli BL21(DE3)was obtained upon induction with IPTG at 20°C.The recombinant lipase activity was approximately 1631-fold higher than the wild type.His-tagged recombinant lipase was purified rapidly and efficiently by using Ni-charged affinity chromatography with 63.5%recovery and a purification factor of 10.78.The purified lipase was stable in a broad range of temperatures and pH values,with the optimal temperature and pH being 50°C and 7.0,respectively.Its activity was stimulated to different degrees in the presence of metal ions such as Ca2+,Mg2+,and some non-ionic surfactants.In addition,the purified lipase was activated by a series of water-miscible organic solvents such as some short carbon chain alcohols and was highly tolerant to some water-immiscible organic solvents.