Impact Analysis of Air Gap Motion with Respect to Parameters of Mooring System for Floating Platform

In this paper, the impact analysis of air gap concerning the parameters of mooring system for the semi-submersible platform is conducted. It is challenging to simulate the wave, current and wind loads of a platform based on a model test simultaneously. Furthermore, the dynamic equivalence between the truncated and full-depth mooring system is still a tuff work. However, the wind and current loads can be tested accurately in wind tunnel model. Furthermore, the wave can be simulated accurately in wave tank test. The full-scale mooring system and the all environment loads can be simulated accurately by using the numerical model based on the model tests simultaneously. In this paper, the air gap response of a floating platform is calculated based on the results of tunnel test and wave tank. Meanwhile, full-scale mooring system, the wind, wave and current load can be considered simultaneously. In addition, a numerical model of the platform is tuned and validated by ANSYS AQWA according to the model test results. With the support of the tuned numerical model, seventeen simulation cases about the presented platform are considered to study the wave, wind, and current loads simultaneously. Then, the impact analysis studies of air gap motion regarding the length, elasticity, and type of the mooring line are performed in the time domain under the beam wave, head wave, and oblique wave conditions.

Sensitivity Analysis of Air Gap Motion with Respect to Wind Load and Mooring System for Semi-Submersible Platform Design

A design of semi-submersible platform is mainly based on the extreme response analysis due to the forces experienced by the components during lifetime. The external loads can induce the extreme air gap response and potential deck impact to the semi-submersible platform. It is important to predict air gap response of platforms accurately in order to check the strength of local structures which withstand the wave slamming due to negative air gap. The wind load cannot be simulated easily by model test in towing tank whereas it can be simulated accurately in wind tunnel test. Furthermore, full scale simulation of the mooring system in model test is still a tuffwork especially the stiffness of the mooring system. Owing to the above mentioned problem, the model test results are not accurate enough for air gap evaluation. The aim of this paper is to present sensitivity analysis results of air gap motion with respect to the mooring system and wind load for the design of semi-submersible platform. Though the model test results are not suitable for the direct evaluation of air gap, they can be used as a good basis for tuning the radiation damping and viscous drag in numerical simulation. In the presented design example, a numerical model is tuned and validated by ANSYS AQWA based on the model test results with a simple 4 line symmetrical horizontal soft mooring system. According to the tuned numerical model, sensitivity analysis studies of air gap motion with respect to the mooring system and wind load are performed in time domain. Three mooring systems and five simulation cases about the presented platform are simulated based on the results of wind tunnel tests and sea-keeping tests. The sensitivity analysis results are valuable for the floating platform design.

Strong coupling between height of gaps and thickness of thermal boundary layer in partitioned convection system

A direct numerical simulation(DNS) method is used to calculate the partitioned convection system with Ra number ranging from 10^7 to 2×10^9.Using the boundary layer thickness to normalize the height of gaps d, we find a strong consistency between the variation of the TD number(the average value of the temperature in each heat transfer channel is averaged after taking the absolute values) with the change of the height of gaps and the variation of the TD number with the change of Ra number in partitioned convection.For a given thickness of partition, heights of gaps are approximately equal to 0.5 or 1 time of the thermal boundary layer thickness λθ at different Ra numbers.TD number representing temperature characteristics is almost the constant value, which means that TD number is a function of d/λθ only.Analysis of local temperature field of area in gaps shows that the temperature distribution in the gaps are basically the same when d/λθ is certain.The heat transfer Nu number of the system at d/λθ≈ 0.5 is larger than that of d/λθ≈ 1, both of them have the same scaling law with Ra number and Nu^Ra^0.25.

High temperature magnetic semiconductors: narrow band gaps and two-dimensional systems

Magnetic semiconductors have been demonstrated to work at low temperatures, but not yet at room temperature for spin electronic applications. In contrast to the p-type diluted magnetic semiconductors, n-type diluted magnetic semiconductors are few. Using a combined method of the density function theory and quantum Monte Carlo simulation, we briefly discuss the recent progress to obtain diluted magnetic semiconductors with both p- and n-type carriers by choosing host semiconductors with a narrow band gap. In addition, the recent progress on two-dimensional intrinsic magnetic semiconductors with possible room temperature ferromangetism and quantum anomalous Hall effect are also discussed.

Investigation of the stable and the metastable liquidus miscibility gaps in Fe–Sn and Fe–Cu binary systems

Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary system and(ii)the high-temperature melting method combined with isothermal treatment to determine the stable liquidus miscibility gap for a Fe–Sn binary system.The experimental method was adopted according to the characteristics of the liquidus miscibility gap of the specific system.Using the powder metallurgy method,a uniform microstructure morphology and chemical composition was obtained in the DTA specimen,and the phase-separation temperature of the supercooled metastable liquid was measured.The isothermal treatment was applied for the samples inside the stable liquidus miscibility gap;here,equilibrated compositions were reached,and a layered morphology was formed after rapid cooling.The liquid miscibility gaps of the Fe–Cu and Fe–Sn binary systems were measured,and the peak temperatures of the corresponding miscibility gaps were determined to be about 1417°C at x(Cu)=0.465 at%and 1350°C at x(Sn)=0.487 at%,respectively.On the basis of the experimental results,both the Fe–Cu and the Fe–Sn binary systems were thermodynamically assessed.

Miscibility gap and stability of B2 phase in the Co-Al based ternary systems

Information on phase equilibria in the Co-Al based systems which are related to some magnetic and heat resistance materials is important for their microstructural control. Recently, it was proposed with a theoretical calculation on electronic band structure that some Heusler-type alloys Co2XAl （X: Cr and Mn） should be a new type of spinelectronic materials so-called half-metallic ferromagnet. In the case of the Co2CrAl, however, magnetic properties expected from the theoretical work can not been experimentally obtained and the reason has been still unknown. On the other hand, a tunneling magnetoresistance （TMR） effect due to the half-metallic properties was reported in Co2（Cr<sup>0.6 Fe<sup>0.4 ）Al alloy, but not the Co2CrAl alloy.In the present paper, it is reported that this discrepancy with the theoretical work in the Co2CrAl alloy is bought about by phase separation between A2 and B2 phases, and that the substitution of Fe for Cr can suppress the precipitation of A2 phase in the B2 phase. Such a phase separation is originally due to the miscibility gap between CoAl and Cr formed in the Co-Al-Cr ternary system as well as that reported by Hao et al. in the Ni-Co-Al-Fe system.

公平竞争审查制度能否缩小企业内部薪酬差距?

缩小企业内部薪酬差距对缓解收入不平等和实现共同富裕具有重要意义。本文基于2010—2020年中国A股上市公司数据,运用双重差分模型实证检验了公平竞争审查制度对企业内部薪酬差距的影响及其作用机制。研究结果显示:公平竞争审查制度缩小了企业内部薪酬差距,其对高管平均薪酬有显著负向影响,而对普通员工平均薪酬的影响不显著;公平竞争审查制度对企业内部薪酬差距的影响在非国有企业、高管持股比例较高企业和产业政策扶持行业的企业更明显;公平竞争审查制度通过促进市场竞争、规范政府补贴和规范税收优惠缩小企业内部薪酬差距;公平竞争审查制度对企业内部薪酬差距的影响是通过缩小超额薪酬差距实现的。本文丰富了企业内部薪酬差距影响因素方面的研究,也为进一步探索企业内部薪酬差距的治理机制提供了新视角。

Dynamic development model for long gap discharge streamer-leader system based on fractal theory

Establishing a long air gap discharge model considering the streamer-leader transition and randomness of the discharge path is of great signiflcance to improve the accuracy of discharge characteristic prediction and optimize external insulation design.Based on fractal theory and thermal ionization theory of streamer-leader transition,this work establishes a dynamic development model for the long air gap discharge streamer-leader system,which includes streamer inception,streamer development,leader inception,development of streamer-leader system and flnal jump.The positive discharge process of a 3 m rod plate is simulated to obtain the fractal distribution of the discharge path and the law of leader development for comparison with the discharge test results.The results show that the simulation model is similar to test results in the development characteristics of leader path distribution,each stage time and leader velocity.Finally,a simulation calculation of a 50%breakdown voltage of the rod-plate gap and ball-plate gap is carried out,with results fairly consistent with test data,proving the effectiveness and practicality of the model.

High Immunization Coverage but Delayed Immunization Reflects Gaps in Health Management Information System (HMIS) in District Kangra, Himachal Pradesh, India—An Immunization Evaluation

Background: Complete and timely childhood immunization is one of the most cost-effective interventions in improving child survival in developing countries. Computerized HMIS has been recently introduced to collect aggregated data on service beneficiaries in Himachal Pradesh. HMIS provides coverage estimates for immunization while information on timeliness is currently not available. Hence we conducted a study to validate coverage and assess the timeliness of immunization in Kangra District of Himachal Pradesh. We surveyed mothers (224) of children aged 12 - 23 months (as on January 2008) and selected 32 clusters in the district between January and March 2008. Design/Methods: We conducted a cross sectional survey and selected 32 clusters by probability proportional to size method whereas seven eligible children per cluster were randomly selected. We interviewed mothers using a structured interview schedule, examined immunization card & looked for Bacillus Calmette Guierre (BCG) Scar. Vaccination after 30 days from national schedule was considered “delayed”. We computed proportions of children completely immunized, immunization delayed, frequency of reasons for delay and 95% Confidence Interval (CI) for significance of associated factors. We conducted a case control analysis of factors associated with timely immunization by taking timely immunized children as cases and delayed immunized ones as controls. Results/Outcome: Reported coverage was universal (100%). Validated full immunization coverage was 94.2% by card/record & 99% by history. Only 29.5% (CI = 20.6% - 37.4%) of children were fully immunized as per schedule (delay less than 30 days). Median delay was 21 days for BCG, 28 days for Diptheria Pertussis Tetanus (DPT 3) and 25 days for measles. Among those with delayed vaccinations, reasons were forgetfulness (36%), lack of correct knowledge (27%) & mother gone to parents’ home (27%) & insufficient children in a camp to open full dose BCG vial (22%). Our case control analysis of timely vaccinated versus delayed vaccination revealed that “precall” (reminder) was significantly [OR = 0.1, CI = 0.2 - 0.5] protective against delayed vaccination. Logistic Regression of delay > 30 days revealed that having returned unimmunized from immunization camp earlier due to insufficient children to open vaccine vial (because of high wastage factor) was significantly associated with delayed immunization (p = 0.0000), while knowledge of date of immunization camp was significantly protective from delayed immunization (p = 0.0026). 68% of the children were having at least one immunization delayed over 30 days from recommended schedule, while the proportion of children whose immunization was delayed by over 90 days was 9.4%. Conclusions: Validated field coverage estimates are lower than reported which can be due to inclusion of children of migrants in numerator & not in the denominator. High proportion of children (>70%) were delayed, suggesting implications for WHO’s strategy of measles control & national Tuberculosis (TB) control programmes, as 4.5% of them had suffered from measles. To avoid delays we recommend (i) use of mono dose vials for BCG;(ii) precall notice to mothers;(iii) modification of HMIS software to track immunization status and timeliness of individual beneficiaries rather than aggregate numbers.

gap度量下线性时变系统的最优鲁棒性

本文主要研究了离散时间线性时变(Linear time-varying,LTV)系统中基于gap度量的鲁棒性优化问题,该问题涉及最大稳定性边缘的计算。借助套代数中算子的内外因子分解方法,推导出了最大稳定性边缘的公式,并证明了一致渐近时不变LTV系统最优控制器的存在性。

基于信息间隙决策理论的含碳捕集−电转气综合能源系统优化调度

【目的】为科学统筹综合能源系统运行经济性、稳定性和低碳性优化目标,采用何种技术手段以提升能源转化效率,减少系统能源浪费和区域环境污染,是当下综合能源系统合理优化的主要问题。为此,提出一种基于场景生成与信息间隙决策理论的含碳捕集与封存(carbon capture and storage,CCS)—两段式电转气(power to gas,P2G)综合能源系统低碳优化策略。【方法】在技术层面,通过对电P2G两阶段精细化建模,提高氢能利用效率,建立热电联产(combined heating and power,CHP)-CCS-P2G耦合模型;在市场机制层面,引入阶梯型碳交易模型以降低系统中CO_(2)排放量。最终,基于信息间隙决策理论(IGDT)构建不同风险偏好下的优化调度模型。【结果】以典型综合能源系统进行算例分析,仿真结果表明所提模型可提高风光消纳率,实现系统低碳、经济、稳定运行。【结论】该优化策略可有效帮助决策者根据其风险偏好制定风险规避与风险追求策略下的调度方案,实现系统不确定性与经济性的平衡。

有效-有为-有爱的三次分配制度构建——基于广东省居民收入差距拉大的分析

收入差距缩小是共同富裕的重要标志之一,优化收入分配制度是缩小收入差距的重要举措。通过分析2013—2022年广东省居民收入数据发现:行业收入差距明显;城乡居民可支配收入差距变大;珠三角与粤东西北地区的人均可支配收入差距进一步扩大。这种现象主要是受统一要素市场不成熟、转移支付与税制建设不足以及社会互助激励欠佳复合影响的结果。未来应促进要素自由流动和强化规则衔接来提高初次分配份额;延续提低-扩中-调高思路,分步骤优化再分配机制;弘扬广济善助的美德,加大第三次分配力度,最终形成有效-有为-有爱的三次分配制度。

1180 MPa级超高强钢冷连轧过程的厚度综合控制技术

针对超高强钢在冷轧过程中厚度波动大以及带头带尾厚度超差的问题,首先根据金属秒流量模型建立了厚度超差预测模型与辊缝调节量预估模型;随后开发了轧制过程中的厚度控制系统,并进行了辊缝调节量优化;最后建立了带钢头尾轧制过程中的轧制速度与张力优化模型。以国内某冷连轧机组的第1机架为技术应用对象,选择两种典型的超高强钢进行生产测试,测试结果表明:超高强钢AR4146E1与DU6220A1的厚度超差长度分别从70.3 m、36.89 m下降到了16.85 m、16.33 m。

中药材GAP实施的复杂系统论

目的 :为中药材GAP实施提供新的思路和管理模式。方法 :在简要总结中药材GAP实施存在问题的基础上 ,提出中药材GAP实施是复杂系统 ,并对其系统结构、特点以及实施的方法论等问题进行了初步探讨。结果 :中药材GAP实施是一个复杂系统 ,由中药材生物系统、环境系统和管理经营系统组成 ,有其自身特点和方法论。结论 :目前GAP实施存在较多问题 。

中药材GAP实施的复杂系统论——生产基地的选建:生态、文化和经济

目的 探讨中药材 GAP生产基地建设所应注意的问题和原则。方法 从生产基地建设的生态、文化、经济内涵入手 ,分析其相应的规律。结果 生产基地的建设中生态、文化、经济等因素相互影响制约 ,组成一个复杂系统。结论 中药材 GAP实施的生产基地建设 ,要把生态、文化、经济等因素考虑进去 ,兼顾环境、社会、经济综合效益 ,才能体现出中药材

高温超导磁浮车直线电机悬挂系统主动控制

高温超导磁浮列车在运行过程中会受到轨道随机不平顺及直线电机法向力的影响,导致车体、磁浮架和电机的振动耦合,电机的振动会引起气隙变化,进一步导致法向力的变化,变化后的法向力反作用于电机悬挂系统,影响磁浮架和车体振动。为了减少因电机气隙变化,文章在电机动子与磁浮架之间添加悬挂系统,同时将主动控制技术应用在悬挂系统上,建立了带主动控制器的高温超导磁浮车动力学理论模型,以轨道随机不平顺和电机法向力作为外部激励,在MATLAB/Simulink中使用PID和Fuzzy-PID控制器对电机动子动态响应进行了仿真,并与被动悬挂系统进行了比较,验证了控制方法的可行性。仿真结果表明,相比于被动悬挂系统,使用两种控制方法能够较好抑制电机气隙波动,且Fuzzy-PID的控制效果要明显优于PID控制。该方法为直线电机振动抑制提供了新思路,并通过仿真验证了该方法的可行性。

基于良好农业规范(GAP)的茶叶质量溯源系统研究

针对茶产业质量安全问题,在探讨良好农业规范GAP的基础上,研究设计茶叶GAP关键控制点和生产过程条码化管理方法,利用Visual C#.NET面向对象编程技术和SQL Server 2005关系型数据库技术,采用二维码(QR code)标识方法,开发了茶叶质量溯源管理客户端软件和茶叶二维码溯源查询系统。应用表明,该系统实现了茶叶企业根据GAP种植规程指导茶农进行规范化生产,为确保茶叶质量安全生产提供一种有效手段,同时为政府监管提供溯源依据。

自然保护区网络体系建设的GAP分析研究——以安徽省自然保护区为例

利用生物多样性保护的地理途径(又称Gap分析)方法,通过对较大尺度区域的植被状况、物种分布及其丰富度的分析,识别生物多样性保护热点地区,确定目前生物多样性保护的空白、遗漏区域,是目前生物多样保护与自然保护区建设发展研究的方向。利用Gap分析方法,识别安徽省自然保护区建设中生物多样性保护的空白、遗漏区域,探讨符合安徽省实际的自然保护区网络体系构建方法及其在景观尺度上的表现,为自然保护区的合理建设与科学管理服务。

基于GAP技术的地震信息网络系统改造方案

江苏省地震信息网络系统是全省区域地震数据传输、数据交换、数据存储及信息服务的统一平台.针对网络系统目前存在的问题,提出了改造方案,即通过使用隔离网闸将业务传输系统和互连网进行物理隔离,升级网络关键设备和链路带宽,增加网络安全设备等技术手段,使网络系统达到了安全、稳定运行的目标,既满足了地震信息数据传输、交换、存储及多元化应用等的需求,又符合信息系统三级安全管理要求,可以为地震行业信息网络系统优化建设提供有益参考.

基于DET云南三七GAP专家系统开发研究Ⅰ——栽培技术咨询子系统

根据国家GAP认证要求,将计算机网络信息,人工智能及多媒体等技术与GAP规范技术结合起来,研究开发出基于DET开发平台的三七GAP专家系统,并根据三七的生产特点及GAP实施的实际进行了软件资源的2次开发,降低了客户端的专业要求,实现了人机操作界面直观、明了。该系统的推广应用,为三七GAP的推广和咨询服务提供了新途径。介绍了三七GAP农业专家系统目标、咨询系统结构、系统内容和功能。