Derivation of Plastic Work Rate Done per Unit Volume for Mean Yield Criterion and Its Application

In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield （MY） criterion. The mathematical relationship of the criterion and its plastic work rate done per unit volume were derived. A generalized worked example of slab forging was analyzed by the criterion and its corresponding plastic work rate done per unit volume. Then, the precision of the solution was compared with those by Mises and Twin shear stress yield criterions, respectively. It turned out that the calculated results by MY criterion were in good agreement with those by Mises criterion.

Optimizing Factory Performance for Unit Cost in Semiconductor Manufacturing

The integrated circuit (IC) manufacturing process is capital intensive and complex. The production process of unit product (or die, as it is commonly referred to) takes several weeks. Semiconductor factories (fabs) continuously attempt to improve their productivity, as measured in output and cycle time (or mean flow time). The conflicting objective of producing maximum units at minimal production cycle time and at the highest quality, as measured by die yield, is discussed in this paper. The inter-related effects are characterized, and a model is proposed to address this multi-objective function. We then show that, with this model, die cost can be optimized for any given operating conditions of a fab. A numerical example is provided to illustrate the practicality of the model and the proposed optimization method.

Variation Character of Grain Yield per Unit Area in Main Grain-producing Area of Northeast China

Based on the surveys and the statistic data during 1980-2003, the variation character of grain yield per unit area in Northeast China and its main factors have been discussed by the methods of statistics and grey correlation analysis. The results show that: 1) the grain yield per unit area has been taking on an increasing trend in the recent 20 years. It increased from 2519.80kg/ha in 1980 to 4216.11kg/ha in 2003, with an increasing rate of 67.32%; 2) the variation of grain yield per unit area is considerably prominent and its range is also very great, with the maximal increase rate of 42.59% and maximal decrease rate of 21.13%, respectively, which are far above the whole Chinese average level; 3) the variation of main crops' yield per unit area is remarkable, which takes on the character that the yield of corn is much higher than that of soybean and rice; and 4) the grey correlation analysis shows that the most important factors impacting the variation of grain yield per unit area are the total power of agricultural machinery, the consumption of chemical fertilizer and effective irrigated area. However, the influence of natural disaster and income level should not be ignored. Effective ways to improve grain yield per unit area are to construct farmland improvement groundwork, reclaim the middle- and low-yield farmland, etc.

Introduction and recent progress of BRAIN Initiative in the United States

The presidential research program Brain Research through Advancing Innovative Neurotechnologies(BRAIN)Initiative was established5years ago in the United States;it has been a driving force of the United States government and private factors to promote technology development in basic and translational neuroscience research.We here summarize the research plan and recent progress in cellular neuroscience,electrical and optical engineering,chemical and systems neurobiology,and brain mapping technologies.The research plan recognizes the importance of identifying different cell populations and unknown cell types in the human brain and diseased models.Technological advances in multielectrode arrays and chemical flow measurement probes not only demonstrate the capacity of detecting neural activities in large areas,but also enable a new era of studying the neural coding information.Large-scale coordination of neuronal activity and brain mapping information will allow for the identification of therapeutic targets in neurological disorders,which is benefited by big data acquisition and analysis.Specifically,increased brain databases will expedite the dissection of thoughts,emotions,cognition,and will thereby help the development of better understanding and treatments of brain disorders.Since cell therapy demonstrates potential for regenerative medicine,the utilization of the newly advanced technologies may further improve the translational potentials and precision controls of transplanted grafts.The development of new diagnostic and therapeutic tools also requires international collaborations on science,technology,advocating,healthcare and medical ethics to advance the innovation and clinical practices.

Changes in underflow solid fraction and yield stress in paste thickeners by circulation

The trouble-free and efficient operation of paste thickeners requires an optimal design and the cooperation of each component.When underflow discharging is suspended,alleviating the vast torque that the remaining solids within the thickeners may place on rakes mainly lies in the circulation unit.The mechanism of this unit was analyzed,and a mathematical model was developed to describe the changes in underflow solid content and yield stress.The key parameters of the circulation unit,namely,the height and flow rate,were varied to test its performance in the experiments with a self-designed laboratorial thickening system.Results show that the circulation unit is valid in reducing underflow solid fraction and yield stress to a reasonable extent,and the model could be used to describe its efficiency at different heights and flow rates.A suitable design and application of the circulation unit contributes to a cost-effective operation of paste thickeners.

Palliative care for acute kidney injury patients in the intensive care unit

Patients with acute kidney injury(AKI) in the intensive care unit(ICU) are often suitable for palliative care due to the high symptom burden. The role of palliative medicine in this patient population is not well defined and there is a lack of established guidelines to address this issue. Because of this,patients in the ICU with AKI deprived of the most comprehensive or appropriate care. The reasons for this are multifactorial including lack of palliative care training among nephrologists. However,palliative care in these patients can help alleviate symptoms,improve quality of life,and decrease suffering. Palliative care physicians can determine the appropriateness and model of palliative care. In addition to shared decision-making,advance directives should be established with patients early on,with specific instructions regarding dialysis,and those advance directives should be respected.

Transnational Mathematics and Movements: Shiingshen Chern, Hua Luogeng, and the Princeton Institute for Advanced Study from World War II to the Cold War

This paper reconstructs,based on American and Chinese primary sources,the visits of Chinese mathematicians Shiing-shen Chern陈省身(Chen Xingshen)and Hua Luogeng华罗庚(Loo-Keng Hua)4 to the Institute for Advanced Study in Princeton in the United States in the 1940s,especially their interactions with Oswald Veblen and Hermann Weyl,two leading mathematicians at the IAS.It argues that Chern’s and Hua’s motivations and choices in regard to their transnational movements between China and the US were more nuanced and multifaceted than what is presented in existing accounts,and that socio-political factors combined with professional-personal ones to shape their decisions.The paper further uses their experiences to demonstrate the importance of transnational scientific interactions for the development of science in China,the US,and elsewhere in the twentieth century.

Catch per unit effort,maximum sustainable yield and exploitation of demersal fish of Omani artisanal fishery

Objective:To evaluate exploitation status of the stocks of demersal fishes in Omani artisanal fisheries.Methods:Time-series data between 2005 and 2014 on catches and effort represented by the number of fishing boats were used to estimate catch per unit effort and maximum sustainable yields applying Schaefer surplus production model.Regression analyses were made online using GraphPad software.Results:The study revealed that increasing the number of boats on the fishery caused a decrease of catch per unit effort of some species.Maximum sustainable yields and exploitation status were estimated for these species applying.Conclusions:Some demersal fish species were found to be caught in quantities exceeding maximum sustainable yields during some fishing seasons indicating overexploitation of their stocks.

Analysis of Yield Components of Japonica Rice Tong Jing 981 under Different Density and Fertilization Conditions

The yield and yield components of Japonica variety Tongjing 981 under different density and fertilization levels were studied through regression and correlation and path analysis. The results showed that the number of panicles per unit area, number of filled grains per panicle and 1 000-grain weight all had very significant yield increasing effects, and the number of panicles per unit area played a leading role. However, the yield increasing effects of the number of panicles per unit area and number of filled grains per panicle are equally important when the basic seedlings are more or the N fertilizer application rate is large. In practical production, a major factor should be determined among the yield components, and rational cultivation measures should be taken accordingly, to improve yield.

有土斯有粮:高标准农田建设提高了粮食单产吗?

作为“藏粮于地,藏粮于技”战略的重要政策实践,高标准农田建设被期待能够有效实现粮食增产和更好保障国家粮食安全。基于27个省(市、自治区)的面板数据,探索了高标准农田建设对粮食单产的影响及其可能机制。研究发现:(1)高标准农田建设能显著提高粮食单产。替换核心变量、进行非参数估计和考虑内生性的稳健性检验,均证实上述发现可信。(2)机制验证表明,高标准农田建设主要通过提升规模经营、促进技术进步和降低生产风险三大路径来提高粮食单产。(3)异质性分析发现,高标准农田建设对起伏度较小地形、粮食主产区、较发达地区的粮食单产促进效应更大。研究结果表明高标准农田建设确实是夯实粮食安全根基的重要举措,需扎实推进新一轮高标准农田建设工作。

改良膜龈手术在牙龈退缩治疗中的应用

随着人们对美观需求的日益提升,治疗牙龈退缩已经成为牙周科临床常见的患者诉求。临床上主要通过手术的方式治疗牙龈退缩,常见的手术包括游离龈移植术、带蒂瓣技术和双层瓣技术,适应证选择恰当时,通常可以获得满意的效果,但上述术式仍存在一定的不足,如根面覆盖效果不理想等。近年来,学者们针对这些不足陆续提出了一些改良方案来治疗不同程度的牙龈退缩,如改良游离龈移植术,即包含龈乳头及游离龈的牙龈单元移植,可改善受体区血供,提高根面覆盖效果,其针对轻度退缩的部位可获得良好的根面覆盖,同时可增宽角化龈和加深前庭沟,但应用于上颌美学区时可能存在术后牙龈颜色、形态不协调,美学效果欠佳的问题。牙龈瓣采用半厚-全厚-半厚的技术进行制备的改良冠向复位瓣,用于多颗牙牙龈退缩时,以退缩最严重牙为中心的改良切口设计的冠向复位信封瓣技术,可提高根面覆盖效果。不离断龈乳头,使龈瓣形成隧道,以容纳移植物的隧道技术及各种改良的隧道技术,可以有效减少术区的组织损伤,并促进创面愈合。本文通过对各类术式的阐述和文献回顾,总结改良膜龈手术治疗牙龈退缩的临床应用及注意事项,并提出牙龈退缩的治疗方案建议,同时强调牙龈退缩的对因治疗,以达到稳定的根面覆盖效果。创伤小、疗效稳定的手术方式和治疗方法是今后膜龈手术的发展方向。

藏粮于地:土地利用对粮食单产的影响

基于“藏粮于地”战略背景,采用全国10省(区、市)950户农户数据,在将土地利用分为规模经营、可持续耕作、结构调整的基础上,利用普通最小二乘法、两阶段最小二乘法和调节效应模型实证分析土地利用对农户粮食单产的影响效应与路径。结果表明:规模经营对粮食单产的影响呈先增后减趋势,即呈倒“U”形关系,可持续耕作能够显著提升粮食单产,而结构调整显著负向影响粮食单产;规模经营在可持续耕作、结构调整影响农户粮食单产中具有正向调节效应;对于耕地禀赋不同的农户,规模经营、可持续耕作对农户粮食单产的影响存在差异性。

福建漳州平和柚天气指数保险产品设计与定价

柚产业是福建省漳州市平和县的支柱产业,为分散当地柚生产的经营风险,基于福建省漳州市平和县1985−2022年柚产量及对应年份3月中旬至8月上旬的天气数据,将柚单产数据分解成趋势单产和气象单产,并调整单产数据使其转化到2024年的生产力水平下的单产,选用核密度估计法拟合该序列的概率密度函数并用于纯费率厘定;而后利用调整后单产数据和天气数据进行相关性分析,筛选显著的天气指数。结果显示:4月中下旬降雨量指数与调整后单产的线性关系最为显著。对于2024年约定的保障产量51000 kg·hm^(−2)和保险价格2.8元·kg^(−1),即每667m^(2)保险金额为9520元,厘定纯费率为4.0191%、保险费率为4.6220%;对于降雨量指数RI的保险赔付触发值160 mm以及RI的8个分级赔付区间,分别计算得到了对应的赔付事件发生概率,并给出了对应的赔付金额计算公式。

美国培育发展未来产业的经验研究

未来产业是大国之间角力和竞争的焦点。美国不断加强量子信息科技、人工智能、先进制造、下一代通信网络和生物技术等前沿科技和未来产业发展,不同产业间的主要共性举措主要有:强化政策引导,系统研发布局;部门各司其职,相互协调推进;注重平台建设,产学研紧密融合;加强人才培养,建设多层梯队;推动国际合作,提升产业韧性等,产生了较好效果。中国可从中吸取经验,通过统筹协调、完善生态、搭建平台、培育人才和国际合作等方面持续推动未来产业发展壮大,加快培育和发展新质生产力。

农机作业服务提高了粮食单产吗?——来自139个县农机购置补贴十年的历史证据

农业社会化服务是否能促进农业生产率,是推进中国式农业现代化需要回答的重要问题。以粮食生产中的农机作业服务为例,利用全国139个县域在实施农机购置补贴政策后十年间的面板数据,对农机作业服务水平与粮食单产之间的关系进行实证检验。结果发现,在控制了土地、劳动力、资本等投入要素之后,农机作业服务水平对粮食单产具有显著的促进作用,并且该作用在粮食主产区更为凸显;农业机械购置补贴政策使农机作业服务对粮食单产的影响出现阶段性差异,即在政策实施初期“购机”有效促进了“用机”,农机作业服务的粮食增产效应较为明显,而后期着力于“购机”的政策无法保障持续发挥农机作业服务的粮食增产作用。因此,需通过设立农机作业补贴等形式持续有效地发挥农机作业服务的粮食增产效应。

基于遥感多参数和VMD-GRU的冬小麦单产估测

为充分挖掘时间序列遥感参数的时序信息和趋势信息,并进一步提升冬小麦估产精度,以陕西省关中平原为研究区域,选取与冬小麦长势密切相关的生育时期尺度的条件植被温度指数(VTCI)、叶面积指数(LAI)和光合有效辐射吸收比率(FPAR)作为遥感参数,构建耦合变分模态分解(VMD)与门控循环单元(GRU)神经网络的估产模型。应用VMD算法将各个时间序列遥感参数分解为多组平稳的本征模态函数(IMF)分量,选取与原始时间序列遥感参数高度相关的IMF分量进行特征重构,并将重构特征作为GRU网络的输入,以构建冬小麦组合估产模型。结果表明,VMD-GRU组合估产模型决定系数为0.63,均方根误差为448.80 kg/hm^(2),平均相对误差为8.14%,相关性达到极显著水平(P<0.01),其精度优于单一估产模型精度,表明该组合估产模型能够提取非平稳时间序列数据的多尺度、多层次特征,并充分挖掘冬小麦各生育时期遥感参数间的内在联系,获得准确单产估测结果的同时提升了估产模型的可解释性。

基于熵权-TOPSIS耦合法的大南湖七矿含水层富水性评价

为查明大南湖七矿主采煤层顶板含水层的富水性分布情况,在分析矿井水文地质资料的基础上,选取区内地质钻孔作为评价对象,确定影响含水层富水性的主控指标—砂岩等效厚度、脆塑性比、砂泥岩互层数、岩石取芯率、砂地比及渗透系数,并建立相应的归一化专题图。通过熵权-TOPSIS法耦合的综合预测方法,建立了主要含水层富水性评价模型。利用ArcGIS绘制含水层富水性分区图,将研究区富水性分为三个等级,即富水性极弱、富水性较弱、富水性中等。利用区内钻孔单位涌水量、井下异常钻孔涌水量和物探对分区结果进行验证。结果表明:区内3煤上含水层以弱-中等富水性为主,3~7煤含水层主要为极弱-弱富水性,评价结果与实际初步探查情况基本一致,为煤矿水害防治和水资源合理化利用提供一定的参考依据。

高产三萜灵芝新菌株‘沪农灵芝5号’的选育

为选育高产三萜灵芝(Ganoderma lucidum)新品种,以抗杂菌能力强、生物学效率高的‘沪农灵芝1号’(H 1)和三萜含量高、抗杂菌能力弱的‘灵芝G 8’(G 8)为亲本,将原生质体单核菌株进行杂交,从130个杂交组合中筛选出菌丝长势较好的25个杂交菌株,并对其进行栽培试验,考察菌包成品率、生物学效率等农艺性状及子实体三萜含量,从中筛选出杂交菌株Z18。与亲本G8相比,Z18菌包成品率提高66.67%、生物学效率提高22.54%;与亲本H1相比,Z18子实体中三萜含量提高51.26%。ERIC-PCR分析结果显示,Z18与亲本存在遗传差异。Z18达到新品种审定标准,已通过上海市非主要农作物品种认定,定名为‘沪农灵芝5号’。

集成学习结合多源数据预测河南省冬小麦单产

为探讨基于多源数据和集成学习算法预测冬小麦单产的可行性并确定冬小麦单产预测的最佳时间窗,该研究在河南省冬小麦生长季内划分28个不同的时间窗,使用8种不同的机器学习算法及基于Stacking的集成学习算法,利用2003—2018年的多种遥感指数数据、气象数据进行训练并预测2019—2021年单产。结果表明:引入日光诱导叶绿素荧光(solar-induced chlorophyll fluorescence,SIF)特征可以提升河南省冬小麦单产的预测效果;12月至次年5月为机器学习算法预测冬小麦单产的最佳时间窗;Stacking集成学习算法比其他单机器学习算法更适用于河南省县级尺度冬小麦单产预测,预测结果的决定系数为0.816,均方根误差和平均绝对误差分别为580.36和476.01 kg/hm^(2);河南省冬小麦实际单产的空间分布呈西低东高的趋势,预测的单产分布特征与实际单产分布特征相当。研究结果可为冬小麦单产预测提供一种新的方法,也为农作物单产预测模型构建提供新的思路。

动车组高级修工艺数字化管理系统关键技术研究

为解决当前动车组高级修工艺管理存在的问题,基于高级修部件物料清单(BOM,Bill of Materials)和工艺BOM的构建逻辑,以及工艺基础数据标准化、参数化、结构化的实际需要,融合工艺BOM与工艺流程的映射方法,采用SpringBoot+VUE前后端分离的开发架构,设计了高级修工艺数字化管理系统。该系统实现了高级修工艺编制规范的统一和编制流程的优化,可自动生成工艺流程图和甘特图,并将准确的规格数据传输到制造执行系统(MES),已在中国铁路上海局集团有限公司上海动车段转向架车间开展应用,满足工艺数字化管理和辅助数字化生产的需要。