轮胎螺母温挤压工艺的探讨

文章提出一种用温挤压工艺成形轮胎螺母的新工艺,指出了两种工艺的不同点,给出了轮胎螺母温挤压工艺参数中的温度、润滑剂和模具材料,介绍了模具结构的要点。     

真空吸水工艺在混凝土施工中的应用

混凝土真空吸水工艺是提高工程质量、加快施工进度的一种先进工艺,现浅谈了真空吸水工艺在混凝土施工中的应用。     

水转印行业生产过程对环境的影响特点及其环保措施

水转印工艺是目前国内应用最广的汽车内饰件表面装饰工艺,其成型简单,图案多样,极大地提升了汽车内饰的视觉效果。但水转印工艺对环境、对人体都有极大的伤害,是一种并不环保的工艺。文章对水转印的工艺过程进行了介绍,并论述了几种可以替代水转印工艺的环保工艺。     

固液双态通用蒸馏设备的初步设计

本文根据蒸馏的操作方法分类,结合酒精蒸馏与精馏工艺要求以及当前企业所普遍使用的蒸馏设备的优点与不足,开发出一种多功能固液双态通用蒸馏乙醇的新工艺。根据该工艺设计出了一种固液双态通用蒸馏设备,并对蒸馏设备的组成部分和设备的工艺效果进行综合概述。     

浅析白钨分解的理论与工艺

本文论述了白钨分解的几种工艺,总体来说包括NaOH分解工艺、Na_2CO_3高压浸出工艺等难溶性钙盐碱法浸出工艺以及使用HCl浸出、HNO_3浸出生成固体钨酸的可溶性钙盐的酸法浸出工艺。另外还介绍了硫磷混酸协同分解工艺和NaF分解工艺等其他能够有效浸出白钨的工艺。目前白钨分解工艺中均存在各种各样的问题,现在急需开发出一种清洁高效的分解工艺来实现钨行业可持续发展的目标。     

对我国常用污水处理工艺研究

本文主要对我国常用污水处理工艺(活性污泥法和生物膜法)的各种变形工艺进行了分析,阐明了各种工艺的原理及优缺点.同时也介绍一种目前污水处理厂升级改造常选工艺-移动床生物膜污水处理工艺,为其他污水处理厂升级改造提供方案.     

关于煤层气裸眼井注入/压降测试管柱设计

由于煤层气裸眼井在测试开采中,注入/压降工艺是对每层进行定量和定性的一种手段,是不可或缺的重要环节。本文针对贵州煤气层的具体参数以及存在的问题,设计了一种新的工艺管柱。     

振动时效工艺在刀辊焊接结构件中的应用

通过对比分析时效处理的三种方法,阐述了振动时效的特点和工艺参数选择要点,介绍了振动时效工艺在刀辊焊接结构件的成功应用。振动时效是一种简便、快捷、有效、节能、环保的先进工艺,能在很大程度上替代热时效。     

浅析MSBR污水处理工艺及自动化控制

结合某污水处理厂介绍MSBR污水处理工艺,该工艺是一种改良型SBR工艺,具有流程简洁、控制灵活、单元操作简单而且占地省等特点,并介绍了该污水处理工艺的计算机自动控制方案。     

浅析连续缠绕玻璃钢管道的市场前景

在竞争不断的激烈的玻璃钢管道制造行业中,传统制造工艺已无法满足现今需求,一种新兴的连续缠绕玻璃钢管道工艺正在逐渐替代传统制造工艺。本文简述了玻璃钢管道的特性及优点、往复式玻璃钢管道制造工艺、连续缠绕玻璃钢管道制造工艺。     

Tail risk and investors’ concerns: Evidence from Brazil

I estimate tail risk for Brazil from January 2001 to July 2020 and investigate the origins of tail risk variation. The tail risk measure peaks at stock market crashes, financial crises, political shocks and disaster events such as the coronavirus pandemic. Moreover, I find that tail risk is countercyclical, has strong predictive power for market returns and negatively predicts real economic activity. In order to identify the investors’ concerns associated with tail risk, I extract daily news from the largest financial newspaper in Brazil. The co-movement between news and tail risk indicates that tail risk variation is mainly driven by disaster concerns, followed by economic and government uncertainty. While economic uncertainty explains the countercyclical property of tail risk, investors only require compensation for bearing tail risk implied by disaster concerns. Similarly, tail risk negatively impacts real outcomes because of the disaster concerns that it identifies. These findings support recent models explaining asset pricing puzzles with time-varying disaster risk.     

聚丙烯酰胺水解尾气回收装置运行探讨

介绍了大庆炼化公司聚丙烯酰胺水解机尾气处理装置的工艺流程及其运行效果,实验结果表明,该装置能够很好的处理聚丙烯酰胺水解机尾气,氨气去除率达90%以上,完全达到了尾气治理的目标。本文对尾气回收装置运行可行性进行探讨。     

Limitations of portfolio diversification through fat tails of the return Distributions: Some empirical evidence

This study investigates the level of risk due to fat tails of the return distribution and the changes of tail fatness (TF) through portfolio diversification. TF is not eliminated through portfolio diversification, and, interestingly, the positive tail has declining fatness until a certain level is reached, while the negative tail has rising fatness. This indicates that fat tails are highly relevant to common factors on systematic risk and that the relevance of common factors is higher for the negative tail compared to the positive tail. In the portfolio diversification effect, the declining fatness of the positive tail further reduces risk, but the rising fatness of the negative tail does not contribute to this effect. The asymmetry between the fatness of the positive and negative tails in the return distribution corresponds to the asymmetry of the trade-off relationship between loss avoidance and profit sacrifice that is expected as a consequence of portfolio diversification. Investors use portfolio diversification to reduce their risk of suffering high losses, but following this strategy means sacrificing high-profit potential. Our study provides empirical confirmation for the practical limitation of portfolio diversification and explains why investors with diversified portfolios suffer high losses from market crashes. An examination of the Northeast Asian stock markets of China, Japan, Korea, and Taiwan show identical results.     

影响长尾理论在网络营销中发挥作用的因素初探

基于统计分析得出的长尾理论在网络营销领域日益受到重视,本文从消费行为的角度探讨了影响长尾理论在网络营销中发挥作用因素,提出在网络营销中口碑控制是影响长尾理论发挥作用的核心因素。对网络营销管理有一定的借鉴意义。     

对于"长尾企业"关系营销中顾客关系的探讨——基于长尾理论下顾客关系的探讨

随着互联网的普及,以及技术的飞速发展,"长尾理论"应运而生,"长尾企业"不断涌现,在此环境下怎样来做关系营销?尤其是关于顾客关系这一方面,它是否具有特殊性,怎样来改善长尾企业的顾客关系? 都是值得讨论的.     

Predictability of tail risks of Canada and the U.S. Over a Century: The role of spillovers and oil tail Risks☆

We examine the tail risk spillovers between Canada and U.S. stock markets using over a century data, and also account for the roles of tail risks of other advanced economies (France, Germany, Japan, Italy, Switzerland, and the UK) and oil-market tail risk. We use the “best” tail risk measure obtained from different variants of the Conditional Autoregressive Value at Risk (CAViaR) model developed by Engle and Manganelli (2004) in the predictive model and compare its performance with that of an AR(1) benchmark model. We find strong evidence of risk spillovers between the two stock markets. We find contrasting evidence for the predictability of oil-market tail risk, with positive predictability in case of the net oil exporter and negative in case of the net oil importer. Further results using tail risks of other advanced economies (combined) support possible diversification potential for Canadian stocks in the presence of market risks of advanced economies other than the U.S. Our findings have implications for investors and are robust to various out-of-sample forecast horizons, alternative data frequencies, data splits, and 1% and 5% VaRs.     

贯流式水轮机尾水流道模板设计与效果

贯流发电机组尾水流道为喇叭口形状,因此混凝土施工时必须采用异型模板,本文介绍峡江水利枢纽东电水轮机尾水流道模板设计,阐述尾水流道模板设计质量控制要点及施工后实际效果。     

GARCH models,tail indexes and error distributions: An empirical investigation

We perform a large simulation study to examine the extent to which various generalized autoregressive conditional heteroskedasticity (GARCH) models capture extreme events in stock market returns. We estimate Hill's tail indexes for individual S&P 500 stock market returns and compare these to the tail indexes produced by simulating GARCH models. Our results suggest that actual and simulated values differ greatly for GARCH models with normal conditional distributions, which underestimate the tail risk. By contrast, the GARCH models with Student's t conditional distributions capture the tail shape more accurately, with GARCH and GJR-GARCH being the top performers.     

Telling tales from the tails: High‐dimensional tail interdependence

We propose a simple and flexible framework that allows for a comprehensive analysis of tail interdependence in high dimensions. We use co‐exceedances to capture the structure of the dependence in the tails and, relying on the concept of multi‐information, define the coefficient of tail interdependence. Within this framework, we develop statistical tests of (i) independence in the tails, (ii) goodness‐of‐fit of the tail interdependence structure of a hypothesized model with the one observed in the data, and (iii) dependence symmetry between any two tails. We present an analysis of tail interdependence among 250 constituents of the S&P 250 index.     

直升机尾桨涡环状态研究

介绍了直升机尾桨涡环状态的现象,分析比较了三种涡环判据的应用特点。针对某型直升机尾桨涡环状态,计算了其侧飞临界速度和临界悬停回转角速度。描述了实际飞行中直升机进入尾桨涡环状态的现象,提出了改出尾桨涡环状态的方法。