检索结果-南通市图书馆

Vibration Frequency Characteristic Study of Two-stage Excitation Valve Used in Vibration Experiment System

Mechanical Engineering Science 2020年第1期2卷 30-35页

作者： Yongping WU Chengwei XIONG Yi LIU Jiafei ZHENG Mingxuan ZOU ningboTech University Ningbo 315100China ningbo Shenglong Automotive Powertrain Systems Co. Ltd Ningbo 315105China

To satisfy the demands of higher frequency and amplitude in hydraulic vibration experiment system,the two-stage excitation valve is presented,and a mathematical model of two-stage excitation valve is established after analyzing the working principle of two-stage excitation valve,then the influence of relevant parameters on the displacement of main spool of two-stage excitation valve is studied by using Matlab/Simulink to calculate and *** results show that the displacement of main spool will be smaller with bigger diameter and more secondary valve *** the reversing frequency is higher and the oil supply pressure is lower as well as the axial guide width of valve ports is smaller,the maximum displacement of main spool is *** new two-stage excitation valve is easy to adjust reversing frequency and *** high frequency can be achieved by improving the rotation speed of servo motor and adding the number of secondary valve ports;the large flow can be realized by increasing the axial guide width of secondary valve ports and oil supply *** result of this study is of guiding significance for designing the rotary valve for the achievement of higher reversing frequency and larger flow.

关键词： two-stage excitation valve rotary valve control mathematical modelling numerical analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

超级稻甬优12不同产量水平群体的钾素营养特性

引用

作物学报 2016年第7期42卷 1047-1057页

作者：韦还和孟天瑶李超张洪程戴其根马荣荣王晓燕杨筠文扬州大学农业部长江流域稻作技术创新中心/江苏省作物遗传生理重点实验室江苏扬州225009 浙江省宁波市农业科学院作物研究所浙江宁波315101 浙江省宁波市种子公司浙江宁波315101 浙江省宁波市鄞州区农业技术服务站浙江宁波315100

2013—2014年,以超级稻甬优12不同产量群体为研究对象,系统比较研究甬优12高产(10.5~12.0 t hm^(–2))、更高产(12.0~13.5 t hm^(–2))、超高产(>13.5 t hm^(–2))3个产量群体的钾素吸收与积累特征差异。结果表明:(1)甬优12超高产、更... 详细信息

2013—2014年,以超级稻甬优12不同产量群体为研究对象,系统比较研究甬优12高产(10.5~12.0 t hm^(–2))、更高产(12.0~13.5 t hm^(–2))、超高产(>13.5 t hm^(–2))3个产量群体的钾素吸收与积累特征差异。结果表明:(1)甬优12超高产、更高产和高产群体的两年平均产量分别为13.9、12.6和10.8 t hm^(–2)。(2)拔节期植株含钾量呈高产群体>更高产群体>超高产群体;抽穗期和成熟期植株含钾量呈超高产群体>更高产群体>高产群体;拔节期3个产量群体间钾素吸收量差异不显著,超高产群体抽穗期和成熟期钾素吸收量分别为364.1 kg hm^(–2)和374.6 kg hm^(–2),显著高于更高产(326.7kg hm^(–2)、331.1 kg hm^(–2))和高产群体(282.8 kg hm^(–2)、284.1 kg hm^(–2))。(3)随产量上升,植株钾素积累量播种至拔节期随之下降,而拔节至抽穗期随之增加。播种至拔节期钾素积累量与产量呈极显著线性负相关,拔节至抽穗期钾素积累量与产量呈极显著线性正相关。(4)与对照相比,甬优12超高产群体抽穗期和成熟期茎鞘、叶片和穗部钾素吸收量较高且与产量呈显著或极显著线性正相关。(5)与对照相比,尽管甬优12超高产群体钾素吸收总量较高,但其籽粒生产率和钾素偏生产力较低,表明甬优12超高产群体钾素利用率较低,在今后甬优12超高产栽培管理中应重视钾肥的高效利用。最后就提高甬优12超高产群体钾素吸收利用的措施进行了探讨。

关键词：超级稻甬优12 不同产量群体钾素吸收和积累

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于C2C的电子商务信用体系研究(英文)

引用

计算机系统应用 2009年第6期18卷 148-153页

作者：谢意沈玉干红华陈德人浙江大学软件学院浙江杭州310027

Credit problem is the main bottleneck which hinders the development of *** paper analyzes the current representative C2C credit evaluation models of Taobao and Youa,and proposes an improved model. The improved model uses a multi-standard evaluation system and new credit rating *** the evaluation algorithm considers the score of multi-standards,category and price of the commodity together,using a weighted system to calculate the credit score then to determine the credit *** solves the main problems which the current C2C credit rating algorithms haven't *** addition,the model puts forward some identification measures of false trading,the ID verification rules,and a third-party credit certification center, which partly solve the credit fraud problems arising from the credit island and credit ***,the paper compares the improved model with current models to show its superiority.

关键词： C2C 电子商务信用体系网上购物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

一种基于CRM模型的SaaS解决方案(英文)

引用

计算机系统应用 2009年第6期18卷 120-124页

作者：林臻干红华陈德人浙江大学软件学院浙江杭州310027

In the middle of current financial crisis,measures have to be undertaken by working with fine user experience to alleviate the difficulties faced by every software *** the CRM model with traditional SaaS mode,customers have little time and money in purchasing and deploying software resources. Meanwhile,developers will gradually improve the system according to user experience and feedback; besides,provide users with personalized service to obtain users' satisfaction and *** ultimate goal is to gain considerable profits for these companies to tide over the period of financial crisis.

关键词： CRM模型 SaaS 软件计算机

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comparison on Purification Effect of Two Macroalgae Species on Prawn Tailwater

引用

Agricultural Biotechnology 2021年第2期10卷 102-106页

作者： Tingting ZHOU Jing HE Zhihua LIN Lin HE Ninghai Institute of Mariculture Breeding and Seed industry Zhejiang Wanli UniversityNingbo 315100China

[Objectives]This study was conducted to investigate the purification effects of two common large seaweeds on the tail water of prawn farming in greenhouses,and to determine the best culture density of seaweeds.[Methods]Two large seaweed species,Gracilaria lichevoides and Ulva lactuca,were selected to set four culture densities of 0.5,2,4 g/L and a blank control group,*** seaweeds were cultured in 100 L white polyethylene buckets,each of which contained 50 L of tail water from prawn culture.[Results]After 5 d,the nutrient removal rates of the two seaweeds were directly proportional to the *** was no significant difference in NH_(4)-N removal rate between *** and ***(P>0.05)by two-way analysis of variance,and the NH_(4)-N removal rate of the latter was *** removal rates of NO_(3)-N,TN and TP by *** were significantly higher than those by ***(P<0.05).The specific growth rates of seaweeds were negatively correlated with their culture *** specific growth rates of *** were 5.73%,1.654%and 0.48%,respectively,and those of *** were 2.01%,1.187%and 0.138%,respectively,when the culture densities were 0.5,2.0 and 4.0 g/***-factor analysis of variance showed that the former was significantly higher than the latter,when the culture density of the two species of seaweeds was 0.5 g/L(P<0.05).The two-way analysis of variance showed that when the culture density of the two kinds of seaweeds was 0.5 g/L,the specific growth rate of *** was significantly higher than that of ***(P<0.05).Based on the above research,the two macroalgae could reduce the nutrients in the wastewater to a large extent,but the culture density determined the scale and economic benefits of seaweed cultivation and further affected the normal growth,metabolism and quality of the seaweeds.[Conclusions]This study provides some theoretical basis for large-scale seaweed farming and biological selection of in-situ ec

关键词： Macroalga Purification efficiency Nutrient salt Aquaculture tail water

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：