霍夫曼及其《西藏手册》

《西藏手册》(Tibet:A Handbook)是赫尔马特·霍夫曼(Helmut Hoffmann)编纂的一部综合介绍西藏地理、历史、政治、宗教、文化、经济、文学和艺术等的参考性工具书。本文简要介绍该书的内容,并对其做了相应的评价。     

在役球罐裂纹缺陷统计与分析

通过对20多台在役球罐的定期检验中发现的裂纹缺陷的数量、位置、尺寸及使用介质等因素进行统计,结果表明：柱腿角焊缝裂纹和内表面裂纹数量最多,焊接接头上的裂纹主要以柱腿和环焊缝为主,裂纹尺寸大部分在50 mm以内。经分析,强力组装引起的拘束力、焊接残余应力、焊接接头的氢含量和淬硬组织的存在是裂纹形成的主要因素,合理控制这些因素能有效地提高球罐的安全性和使用寿命。     

栽培环境对番茄部分数量性状DUS测试结果的影响

为了探索不同栽培环境对番茄部分数量性状DUS测试结果的影响,选取对30个番茄DUS测试标准品种和2个测试品种及其选定的2个近似品种,进行塑料大棚和露地2种不同的栽培环境对番茄10个数量性状的DUS测试结果影响的研究.结果表明:2种栽培环境对除第一花序着生节位和心室数以外的8个数量性状均存在显著或极显著的影响,导致在部分数量性状代码判别和特异性的判定上存在着差异.通过标准品种数量性状分级标准的校正,可以有效消除因栽培环境不同而造成的影响.     

农业文化遗产遴选标准初探

在农业文化遗产普查申报过程中,我们所说的农业文化遗产是特指各种农耕技术、农耕经验、农耕制度、农耕信仰、农业品种均比较健全、比较完备,且这些传统又很符合可持续发展理念的传统农耕文明发祥地或传统农耕文明集散地.在农业文化遗产名录的遴选过程中,我们应重点考察这里是否具有高超的农业生产技术,是否保留有一定数量的传统品种,是否保留有一套严密而高效的农业管理制度,是否保留有传统的农业信仰方式以及与这些信仰息息相关的传统仪式、传统节日等农耕文明的重要载体.由于农业文化遗产通常都是以一定的区域形式申报的,因此还要充分考虑到这里的农耕文化是否与其所处环境和谐相处,并能够巧妙地利用自然以实现农业的丰产丰收和可持续发展.     

A Multistate Life Table Analysis of Union Regimes in the United States: Trends and Racial Differentials, 1970–2002

We estimate trends and racial differentials in marriage, cohabitation, union formation and dissolution (union regimes) for the period 1970–2002 in the United States. These estimates are based on an innovative application of multistate life table analysis to pooled survey data. Our analysis demonstrates (1) a dramatic increase in the lifetime proportions of transitions from never-married, divorced or widowed to cohabiting; (2) a substantial decrease in the stability of cohabiting unions; (3) a dramatic increase in mean ages at cohabiting after divorce and widowhood; (4) a substantial decrease in direct transition from never-married to married; (5) a significant decrease in the overall lifetime proportion of ever marrying and re-marrying in the 1970s to 1980s but a relatively stable pattern in the 1990s to 2000–2002; and (6) a substantial decrease in the lifetime proportion of transition from cohabiting to marriage. We also present, for the first time, comparable evidence on differentials in union regimes between four racial groups.     

A cutting-and-inventory control problem in the manufacturing industry of stainless steel wares

Circular pieces are often cut from stainless steel roll to make common commodities such as pots and cups. The related factories are often make-to-order ones. The stock rolls usually have the same width. Each working order requires pieces of the same size. Pieces of different sizes cannot appear in the same cutting pattern because the orders do not arrive simultaneously. The approach proposed in this paper assumes that the original roll can be slit into a strip and a partial roll. The strip is used to fulfill the current order. The partial roll will be used to fulfill future orders and cannot be slit further. The approach determines several standard widths for the partial rolls and uses a greedy procedure to select the roll (either the original roll or a partial roll) to fulfill the current order. The computational results indicate that the approach is efficient in improving material utilization.     

基于出租车轨迹的广州市活跃度的时空演变分析

研究一天中不同时段的城市活跃度及其稳定性可以为公共基础设施和公共服务设施的空间配置以及公共交通及安全政策的制定提供依据。本文通过出租车GPS数据所表现出的城市活跃度及其稳定性来研究城市的时空间结构形态。研究结果表明:城市活跃度的空间格局呈现出明显的中心外围结构特征,可以视为一种不规则的同心圆模式。不同日期在相同时段内城市活跃度的空间格局也存在差异,一些区域在星期一是城市活跃度一般,而同一时段的星期天城市活跃度较高。从城市活跃度和稳定性的节律特征来看,城市活跃度和稳定性均表现出明显的高峰与低谷,显示城市活跃度具有明显的日常活动的节律性。