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1.
垂叶榕是城市绿化和园林造景中应用的一种重要树种,本文就垂叶榕的生物学习性及在绿化和盆景制作中的管理技术作一简要概述。  相似文献   
2.
随着资本结构研究的深入,理论界进一步放宽MM定理的基本假设。以Jensen,Myers,Ross,Leland,Harris,Hart等学者为代表的新资本结构理论引入最新的研究方法,对资本结构展开分析。本文按照新资本结构理论发展的历史轨迹,全面评述了资本结构理论中最为重要的各种理论,同时系统地描述了各有关理论的基本内容。  相似文献   
3.
电力系统正常运行时,无功/电压控制目的是安全经济供电.而在紧急情况下,首要目标是运行的安全性,其次才是经济性.本文提出的局部网概念及其灵敏度矩阵,以及对电压违限严重性的分级和控制战略,使控制更为快速有效.此法更适用于当事故引起全系统运行数据不全时对局部网的电压控制.  相似文献   
4.
The problem of constructing control charts for fuzzy data has been considered in literature. The proposed transformation approaches and direct fuzzy approaches have their advantages and disadvantages. The representative values charts based on transformation methods are often recommended in practical application. For representing a fuzzy set by a crisp value, the weight of importance of the members assigned with some membership levels in a fuzzy set should be considered, and the possibility theory can be employed to deal with such problem. In this article, we propose to employ the weighted possibilistic mean (WPM), weighted interval valued possibilistic mean (WIVPM) of fuzzy number as a sort of representative values for the fuzzy attribute data, and establish new fuzzy control charts with WPM and WIVPM. The performance of the charts is compared to the existing fuzzy charts with a fuzzy c-chart example via newly defined average number of inspection for variation of control state.  相似文献   
5.
动词复制句(Verb-Copying Construction,VCC)是一种在汉语口语中经常使用的结构,用符号可以简单地表示为S+VP1+VP2,动词V2是动词V1的拷贝。这种结构本身具有独特的句法语义特征,也具有不同的句法变体。在其进行句法运算时,两个动词性结构首先独立运算,VP1作为附加语,VP2作为主句成分进入句法推导。通过附加语侧向移位、附加合并以及主题化特征核查等句法操作形成语言表达式。其句法变体的不同构型是因为不同的控制类型造成的。  相似文献   
6.
The close relationship between quality and maintenance of manufacturing systems has contributed to the development of integrated models which use the concept of statistical process control (SPC) and maintenance. This article demonstrates the integration of the Shewhart individual-residual (ZX ? Ze) joint control chart and maintenance for two-stage dependent processes by jointly optimizing their policies to minimize the expected total costs associated with quality, maintenance and inspection. To evaluate the effectiveness of the proposed model, two stand-alone models—a maintenance model and an SPC model—are proposed. Then a numerical example is given to illustrate the application of the proposed integrated model. The results show that the integrated model outperforms the two stand-alone models with regard to the expected cost per unit time. Finally, a sensitivity analysis is conducted to develop insights into time parameters and cost parameters that influence the integration efforts.  相似文献   
7.
The purpose of this study is to see whether God-mediated control beliefs moderate the relationship between living in rundown neighborhoods and uncontrolled hypertension. God-mediated control refers to the belief that God will help people handle the stressors that arise in life. Data are provided by a nationwide survey of adults (N = 1919). Three ways of assessing uncontrolled hypertension are examined: a binary format contrasting people with and without uncontrolled hypertension, systolic and diastolic blood pressure scored continuously, and a four ordinal category scheme recommended by the American Heart Association. The data suggest that stronger God-mediated control beliefs moderate the relationship between neighborhood conditions and uncontrolled blood pressure when blood pressure is scored continuously and when the American Heart Association scheme are used as outcomes.  相似文献   
8.
We propose to use AR-Sieve Bootstrap in the construction of a control chart of an autocorrelated process influenced by multiple exogenous inputs. The control charts are compared with Exponentially Weighted Moving Average (EWMA) control chart through a simulation study. AR-Sieve bootstrap control limits are narrower than EWMA control limits. While the proposed method yields a higher rate of false alarms, it is quick in detecting even minimal structural changes.  相似文献   
9.
范丹等 《统计研究》2021,38(9):60-74
为探究《大气污染防治行动计划》 (以下简称“大气十条”)的健康效应,本文基于中国健康与营养调查(CHNS)数据及省级面板数据,利用基于多项Logit模型的双重差分法(Logit-DID),从微观与宏观两个维度考察“大气十条”政策的健康改善效应及其传导机制,并进一步通过异质性分析探讨环境健康不平等的内在原因 研究发现:“大气十条”实施带来显著的健康效应,该政策不仅能有效控制与空气污染高度相关疾病的发病率和死亡占比,还能够间接降低受空气污染影响较小的疾病病情。其作用机理主要通过控制PM2.5浓度改善公众健康,同时该政策对二氧化硫(SO2)、氮氧化物、烟(粉)尘等其 他污染物浓度的下降起到了协同作用。进一步分析显示环境福利不公平的现象依然存在,“大气十条”政 策显著降低了疾病高发人群的发病率,且对女性、城镇居民和低、高年龄段等疾病高发人群的健康影响更显著。本文为政府构建环境健康公平发展路径,推进“健康中国”战略提供了经验证据和政策借鉴。  相似文献   
10.
Teenage sole mothers in receipt of welfare benefits are seriously affected by systematic and radical restructuring of Aotearoa/New Zealand’s state welfare system since 2008. With few exceptions, the changes oblige beneficiaries to prioritise obtaining paid work. To address questions of how welfare changes and socio-cultural context in Aotearoa New Zealand are experienced by teenage mothers we conducted a narrative study of 10 young women’s stories of sole mothering as beneficiaries. Purposeful sampling was used to recruit young mothers who were attending, or had recently attended a specialist school for teen parents. Thematic analysis of interview narratives represented experiences of financial and social deprivation, negative stereotyping, stigma and resistance. In contrast to the government’s explicit goal of getting welfare recipients into paid employment, the teenage mothers in our study placed full-time mothering as their principal duty. They also acknowledged the material and social advantages of entering paid employment, and were committed to working but only when their child was ‘settled and ready’ – a decision they understood to be their responsibility.  相似文献   
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