Mode Choice in a Hub-and-Spoke Network: A Zero-One Linear Programming Approach

While research has tackled the hub-and-spoke network design problem, that research has overlooked the air-truck modal integration issue which is a common feature of real express delivery systems. This paper devises integer linear programs to represent the mode and route assignment aspects of the operational problem. The model is solved under four different levels of delivery schedule, and the results show that as the promised delivery schedule is relaxed, not only does the use of truck routes become more desirable, but also interesting adjustments in mode and hub assignment occur. Consider the case of hubs in Los Angeles and Dayton. As the time constraints are relaxed, cities such as Minneapolis and New Orleans originally linked by air to Los Angeles, switch to Dayton because cheaper truck routes become feasible.     

"承上制下"与"从左转右":北宋物资转输区域的互动——以东南地区为中心

北宋时期,朝廷在淮南地区运河沿岸州军设置转般仓,这些州军具有了转般粮食物资进京的功能;又先后置发运司于真州和泗州,使其开始具有总管东南漕运事务的职能;盐利也集中于此,同时亦掌控着地方物资的上供经费.其他物资转输区域则经常出现改变转运方式的情形,中转区域改变了起始区域输出物资的运输方式,减轻了部分运输成本.起始区域在加重中转区域负担的同时,亦对中转区域的经济繁荣有促进作用.     

Micro-CT-assisted determination of the shattering and non-shattering phenotypes of charred rice spikelet bases from archaeological sites: a new methodological approach

The selection of a non-shattering phenotype is a pivotal change in the process of rice domestication. However, current research is heavily restricted by the preservation conditions of macro-plant remains in early and middle Neolithic sites, as very limited well-preserved rice spikelet bases could be retrieved. We present a non-destructive method based on micro-computed tomographic (CT) scanning, which could provide detailed visualization of the internal structures of charred spikelet bases and efficiently discriminate the shattering and non-shattering phenotypes of rice spikelet bases according to the abundance of fusiform echinate phytoliths. It could be widely applied in different contexts, especially those poorly preserved specimens and tempers in pottery sherds, greatly improving our knowledge of rice domestication.     

AN ARTISTIC LIFE CREATED BY A PAIR OF SKILLFUL HANDS

正The cold season isjust about to arrive in Lhasa.A tallllbetan man is standing upon the golden roof of the Jokhang Temple to look out into distance.His name is Tsegya,a man with a deep affection for this very roof.This is the place where his karma connects him to his produced mandalas.Tsegya told me that     

抗战中的知识分子

作者通过对甲午战争至全面抗战爆发历史的回顾,分析期间中国知识分子的思想变化.并分析抗战爆发后知识分子通过不同的方式积极投入救亡运动,重新认识抗战期间的知识分子的真实处境和历史,提出应更理性、客观的去看待抗战时期的知识分子的选择,无论是自由主义知识分子、马克思主义知识分子还是新儒家知识分子,对近代中国文化的追求,根本上都是“三民主义”.     

明初大运河南旺分水枢纽水工技术考

明朝初年,国脉皆仰东南,为解决南方粮财物的北运问题,宋礼和白英受命组织修建了大运河山东段南旺分水枢纽。该枢纽主要包括引汶济运、导泉补源、设立水柜和置闸节流四个组成部分。其中,引汶济运是工程之重点,包括戴村坝、小汶河、南旺分水以及配套工程等四个子系统。这些水利设施组成一个和谐的系统工程,保证了该段运河的水量稳定充足,从而实现了大运河500余年的正常通行。南旺分水枢纽代表了我国古代运河水工的最高科学技术成就,堪称世界水利史上的一大经典范例。     

《唐大和上东征传》鉴真携带品辨正

真人元开(Omino Mihune)撰于779年的鉴真传记<唐大和上东征传>,有多种写本、刊本传世.1762年以后的刊本,流传颇广,其对文本的字词误读甚至影响到今天.本稿依据现存日本的古写本及多种刊本,对鉴真第二次东渡携带品的误读进行辨析、纠谬,指出在研究域外汉籍中写本的重要性.     

断代文献学研究的力作——读张富祥《宋代文献学研究》

山东大学张富祥先生耗费多年精力撰写的《宋代文献学研究》一书,凡75万字。拜读一过,首先想到的是在目前百花竞放的国学研究领域又添一力作,文献学研究尤将受益良多。还在本书正式发行前,《古籍新书报》已有"立论严谨,功力深湛"的评价。这八个字可与书前刘乃和、王绍增、吴怀祺三位名家序言中的评语对看,读者通览全书,自会知道本书的写作非有深厚的积累功夫不能完成。这里略就初读本书的感想谈几点认识。     

SO2与水分综合影响下的云冈石窟砂岩劣化研究

气体污染物SO₂是造成云冈石窟文物本体劣化的重要因素之一。为厘清SO₂与水分耦合作用下的云冈砂岩劣化规律，开展不同SO₂浓度、相对湿度以及降水条件下的室内模拟风化试验，测定试样质量、表面特征和化学成分变化。结果表明：SO₂易与砂岩中的碳酸盐矿物(如方解石)和长石发生化学反应，产物包括CaSO₄·2H₂O、MgSO₄·7H₂O和高岭石等，且随着相对湿度增加，反应程度增大，造成试样的质量、色差值、可溶盐含量上升及硅铝比下降；液态水的参与能显著加快SO₂与砂岩的相互作用过程，不但增加了各项指标的变化幅度，还加大了SO₂入侵深度。研究成果可为砂岩质文物的科学认知和预防性保护提供参考。