双奇数相加的逻辑分析(七)

武钢这样的大型冶金企业,高炉、焦炉、加热炉生产中,双位调节比比皆是。为了从理论上探讨众多双位调节组成的复杂网络,作者考察一个特殊的开关逻辑函数,并用“1“表示奇素数,用“0”表示奇合数,提出了一个幼拉脱斯展纳（Eratosthnes）筛法单步操作的数学描述式。     

一种新型双位蝶阀的研制及在台车式热处理炉的应用

通过一种新型双位蝶阀的研制和使用,解决了热处理炉大小火调节的问题,并且提高了双位蝶阀的可靠性和使用寿命,大大提高了火焰式台车热处理炉的炉温控制稳定性和使用寿命。     

一类三阶拟线性方程组的奇摄动边值问题

本文用间接的方法证明了一类三阶拟线性方程组的奇摄动边值问题解的存在唯一性,并给出了解对小参数任意精确度的一致有效展开。     

自动调节系统的“基础形式”在对数幅频特性上的表现

一、前言 《关于“电子最佳调节原理”的一些问题》一文提出了自动调节系统的“基础形式”和“基础时间常数”的概念,这是系统的固有特征。它能概括地反映该系统的稳定倾向。下面将说明所谓基础形式就是所讨论系统的开环对数幅频特性上有截止频率的一段特性的性质。这个性质就是这一段斜率所表示的几阶积分性质。如图1(a)、1(b)中bc     

库存管理概述和系统设计思想

一、库存管理概述: 库存管理是经济管理中的一个重大问题,也是在解决“无限需求”与希望“库存最小”的矛盾中,寻求最佳条件的一种专门技术。 库存管理的主要职能就是管理和调节供方和求方之间的关系,其概念可用图1表示:     

关于Diophantine方程y2=px(x2+2)的一点注记

设p是奇素数,运用初等数论方法证明了:如果P=16k4+1,这里k为正奇数,则方程y2=px(x2+2)无正整数解(x,y).     

关于Diophantine方程y2=px(x2+2)

对于Diophantine方程y2=px(x2+2),这里p为奇素数,证明了:当p=2593时,它有唯一的正整数解(x,y)=(72,31116).     

一类具有激波层性质的奇摄动拟线性边值问题

研究了一类奇摄动拟线性边值问题,利用匹配渐近展开法,导出该问题在区间内部出现激波层的条件,并给出激波解在整个区间上一致有效的复合展开式.     

世界钢铁工业进入“新连续性周期”

一、世界钢铁工业已从“旧连续性时代”进入“新连续性周期”从旧连续性向新连续性转变的时期,即表示“旧连续性周期”终止、“新连续性周期”开始的时期。在这一时期,充满了危机和机遇。国外研究机构认为钢铁工业的“新连续性周期”始于2003年年中。其根据如下。第一,在2003年     

国产钢管张力减径机双位机座的研制

国产双位机座研制是钢管张力减径机核心备件，是重点攻关项目，其技术复杂，加工难度大，经过精心研制，全面消化吸收引进技术，立足国内现有设备，挖潜创新，使国产双位机座性能达到８０年代国外先进的同类产品水平，经济效益显著提高。     

双奇数相加的逻辑分析（之三）

继《双奇数相加的逻辑分析》和《双奇数相加的逻辑分析（之二）》，专门讨论一任意奇数属性逻辑函数式结构，并由此得出双奇数相加的二元一次不定方程式。     

Introduction of Energy Efficient Solutions During Cast Iron Smelting at PJSC “NLMK”

Metallurgist - The use of coke with hot strength of 60–65% in the blast furnaces of PJSC “NLMK” allowed to increase the intensity of the blast furnace smelting and utilize the...     

“双碳”背景下低碳排炼钢流程选择及关键技术

“碳达峰”、“碳中和”是一个总体的宏观概念,为中国未来经济与环境发展提供了笼统的理论框架与基本理念。基于“双碳”目标的深度解析,中国钢铁行业处于“碳锁定”状态,只有同时进行技术和制度变革才能实现“碳解锁”。结合当前钢铁工业生产结构、冶炼原材料供应、冶炼能源、节能减排水平以及CO₂排放现状,给出了合理的碳达峰时间及峰值。未来二三十年中国钢铁生产主要流程依然是长流程和短流程并存,氢冶金技术还难以进行工业生产,提升全废钢短流程炼钢的比例是降低碳排放的主要措施。从长远来看,长流程中炼铁工艺由碳还原逐渐向氢还原是大势所趋,炼铁工序的产品将由原来的高碳铁水转变为低碳铁水或直接还原铁（DRI）,具有较高脱碳的转炉炼钢就没有明显优势,发展电弧炉炼钢流程是必然选择。但实现“碳中和”还要依靠氢冶金,碳捕集、利用与封存技术的发展和应用,以及制度的变革。基于近年在全废钢电弧炉相关方面的理论研究、装备开发与实践的深入研究,针对全废钢电弧炉冶炼工艺存在的问题,开发了一系列关键技术,实现在全废钢条件下满足当前连铸生产工艺节奏以及钢液质量的控制,为全废钢电弧炉的发展提供理论支持。      

Norican Steel ‐ An Assessment of the Archaeological Finds at the Magdalensberg Site,Carinthia, Compared to the “Celtic Trove” of Gründberg Hill,Linz

The analysis of Celtic steel products from depots found in the area north of the Danube has shown that their excellent properties are due to the choice of unalloyed or alloyed steel bars that were shaped by fire‐forging. Phosphorus was used as an alloying element, while carbon was added through carburizing of the workpiece. Was this forging technique also known to regions in the very heart of the Alps? Our analysis set out to find an answer to this question. The Celtic smiths in the inner Alpine regions used shaft furnaces to produce steel loops with numerous slag inclusions but very low contents of trace elements in the steel matrix. In a series of process steps in the smithy ‐ trimming the steel loop, forging into bars, “sheafing”, carburizing, hardening ‐ the steel properties demanded by the customers were achieved. Phosphorus was not deliberately employed as an alloying metal in the valleys of the Central Alps. The fact that the forging technique was tailored to the actual product appears to underlie the high quality of “Norican steel”.     

基于“炉?机对应”的炼钢?连铸生产调度问题遗传优化模型

针对炼钢?连铸过程因车间布局复杂造成工序间钢水交叉供应频繁、等待时间过长以及天车调度困难等问题,本文建立以计划内所有炉次总等待时间最小为优化目标的炼钢?连铸过程生产调度模型,并采用改进的遗传算法求解该模型。在遗传操作过程中,引入“炉?机对应”调控策略以改善初始种群质量,并根据转炉（精炼）与连铸作业周期的比较,来确定是否对个体进行交叉、变异操作。以国内某中大型炼钢厂主要生产模式下的实际生产计划为仿真算例进行实验,结果表明:本文提出的基于“炉?机对应”的改进遗传算法的性能显著优于基本遗传算法及启发式算法,针对炼钢厂产量占比超过80%的主要生产模式4BOF?3CCM下的算例1,优化了生产过程等待时间,工序间最长等待时间由77 min减小到54 min;炉?机匹配程度也明显提高,3号精炼炉去往3号连铸机的钢水比例由25%提升到67%,减少了个别炉次由于设备随机指派造成的工序设备间对应关系不明确及由于生产路径不合理造成等待时间过长的现象,为研究炼钢厂复杂生产调度问题提供了一种高效的解决方案。      

海外矿山并购项目层面风险评价

项目层面风险是我国海外矿山并购的决定性风险因素之一。在现有研究基础上，对海外矿山并购项目层面的主要风险因素进行了识别，将矿床开采技术条件、地质资源条件等反映矿山生产特征的指标纳入评价指标体系中，使得指标体系更具针对性且更完善。构建了一套包括4个一级指标和11个二级指标的风险评价指标体系；利用TFN-RS方法综合了主客观赋权的双重优势以确定各评价指标的组合权重；基于云理论和物元理论，建立了海外矿山并购项目层面风险评价的云物元模型，运用MATLAB编程计算出各个评价指标的风险等级隶属度，提高了风险模糊性和不确定性的评价精度。使用本方法以中国有色矿业集团有限公司并购赞比亚卢安夏铜矿项目为例，进行项目层面风险评价，结果显示：该项目风险等级为“低”，但外部建设条件风险为“一般”，经济效益条件风险为“较低”。该项目的基础设施和工程地质条件不足，是项目层面风险的主要来源。     

"What counts in the development of young children's number knowledge?": Correction to Levine et al. (2010).

Reports an error in "What counts in the development of young children's number knowledge" by Susan C. Levine, Linda Whealton Suriyakham, Meredith L. Rowe, Janellen Huttenlocher and Elizabeth A. Gunderson (Developmental Psychology, 2010[Sep], Vol 46[5], 1309-1319). A coding error resulted in incorrect item-level data being reported on the point-to-x task (not the children‘s overall performance on this task) in Table 2 and in the section of the Results headed Point-to-X Task Performance (second column, p. 1314). In the first paragraph in the section, the correct average score for knowledge of cardinal meanings of the number words. In the second paragraph in the section, there is an example illustrating children’s greater performance on items involving a target and a distractor that were one digit apart. An additional adjustment in the second paragraph involves the finding that children performed better when at least one of two choice sets was a small number (1–3) than when both choice sets were greater than or equal to 4. More information for the corrections and the corrected table are given in the erratum. (The following abstract of the original article appeared in record 2010-17955-026.) Prior studies indicate that children vary widely in their mathematical knowledge by the time they enter preschool and that this variation predicts levels of achievement in elementary school. In a longitudinal study of a diverse sample of 44 preschool children, we examined the extent to which their understanding of the cardinal meanings of the number words (e.g., knowing that the word “four” refers to sets with 4 items) is predicted by the “number talk” they hear from their primary caregiver in the early home environment. Results from 5 visits showed substantial variation in parents' number talk to children between the ages of 14 and 30 months. Moreover, this variation predicted children's knowledge of the cardinal meanings of number words at 46 months, even when socioeconomic status and other measures of parent and child talk were controlled. These findings suggest that encouraging parents to talk about number with their toddlers, and providing them with effective ways to do so, may positively impact children's school achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What counts in the development of young children's number knowledge?

[Correction Notice: An erratum for this article was reported in Vol 47(1) of Developmental Psychology (see record 2011-00627-019). A coding error resulted in incorrect item-level data being reported on the point-to-x task (not the children‘s overall performance on this task) in Table 2 and in the section of the Results headed Point-to-X Task Performance (second column, p. 1314). In the first paragraph in the section, the correct average score for knowledge of cardinal meanings of the number words. In the second paragraph in the section, there is an example illustrating children’s greater performance on items involving a target and a distractor that were one digit apart. An additional adjustment in the second paragraph involves the finding that children performed better when at least one of two choice sets was a small number (1–3) than when both choice sets were greater than or equal to 4. More information for the corrections and the corrected table are given in the erratum.] Prior studies indicate that children vary widely in their mathematical knowledge by the time they enter preschool and that this variation predicts levels of achievement in elementary school. In a longitudinal study of a diverse sample of 44 preschool children, we examined the extent to which their understanding of the cardinal meanings of the number words (e.g., knowing that the word “four” refers to sets with 4 items) is predicted by the “number talk” they hear from their primary caregiver in the early home environment. Results from 5 visits showed substantial variation in parents' number talk to children between the ages of 14 and 30 months. Moreover, this variation predicted children's knowledge of the cardinal meanings of number words at 46 months, even when socioeconomic status and other measures of parent and child talk were controlled. These findings suggest that encouraging parents to talk about number with their toddlers, and providing them with effective ways to do so, may positively impact children's school achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Steelmaking considerations using smelted iron

Iron produced with several of the “in-bath smelting” technologies may differ from the output of conventional blast furnaces. Carbon content may be driven to below saturation, oxygen content will be high so that a) silicon may be near nil, and b) the sulfur content can reach upward of 10 times higher than achieved with the coke-oven/blast-furnace route. These conditions point to the need for new approaches for conversion of this intermediate liquid into steel.