基于损失特征矩阵的CHB-BESS模块间接地故障诊断

模块间接地故障是H桥级联型电池储能系统(cascaded H bridge based battery energy storage system,CHB-BESS)的易发故障,快速诊断故障位置对减少故障损失至关重要。模块间接地故障的故障特征主要体现在零序电流上,会受到接地过渡电阻的影响。为实现接地过渡电阻不确定情况下,故障模块位置的快速准确鲁棒定位,本工作提出了一种基于损失特征矩阵的快速故障诊断方法。首先,本工作建立了零序等效电路模型;然后,将零序电流模型离散化;接着,提出基于损失特征矩阵的定位方法,该方法使用拓扑矩阵描述故障位置和过渡电阻的遍历信息,基于离散化模型来遍历计算零序电流,将计算结果与测量结果的偏差记录在损失特征矩阵中,通过偏差最优解确定故障位置;其次,本工作证实了故障定位问题作为最优化问题具有最优解唯一性,偏差最优解在接地过渡电阻不确定的情况下可获得准确的故障发生位置;最终,基于最优解唯一性提出了最优化计算的加速方法。实测表明,所提方法的平均定位误差仅为0.2个子模块,在接地过渡电阻较大范围不确定的情况下实现了准确定位,并且所提加速方法显著提高诊断速度。

500kV变电站保护小间接地方式的研究

利用矩量法(ＭｏＭ)和快速傅立叶变换(ＦＦＴ),对一个 ５００ｋＶ变电站遭受雷击时接地网的暂态地电位升进行了数值计算。对保护小间内一些关键点的暂态地电位升进行了分析研究。分析结果表明,保护小间内应该铺设接地网,并且保护小间的接地网与主地网应采用四点连接,连接点应该在保护小间的四个角上。

MN长度误差及接地电阻对卡尼亚电阻率的影响

文章通过理论推导和数值计算结果说明了可控源音频大地电磁测深法(CSAMT)野外工作中由于MN长度误差及MN间的接地电阻对卡尼亚电阻率的影响特征.计算结果表明,由于CSAMT测深中计算电阻率的公式与传统的直流电测深的视电阻率计算公式不同,及所使用的频率范围不同,由接收电极MN长度误差及MN间接地电阻对测量结果所产生的误差与传统的直流电阻率法是不同的.

品牌个性塑造方式浅谈

随着产品同质化现象越来越严重,如何让自己的品牌区别于其它品牌并获得特定消费者认同与崇拜,塑造品牌个性是一个有效的手段。品牌个性是将品牌人格化.它是企业的无形资源。品牌个性塑造的方式有直接与间接两种,笔者以众多的案例事实来就这两种方法进行了细致地阐述。

品牌个性塑造方式浅谈

随着产品同质化现象越来越严重,如何让自己的品牌区别于其它品牌并获得特定消费者认同与崇拜。

论相对与绝对范畴

相对与绝对是哲学中比较难以把握的一对范畴。关于这对范畴的理解,不仅在历史上众说纷纭,就是现在也可以这样说,这对范畴应用在什么问题上,什么问题就经常出现歧议,不断发生争论,例如相对真理与绝对真理,对立面同一性的相对性和斗争性的绝对性等等问题。这些争论首先是由于对内容本身的不同理解所引起的,但也都直接或间接地涉及到如何理解相对与绝对的范畴问题。因此,很有必要去研究一下这对范畴的含义,弄清这一点对于解决当前在一些理论问题上的争论会有一定的帮助。

应该追求 平中出奇——《生活告诉我……》升格示例

[失误作文] 生活告诉我…… 赵军 总是在失去了之后,才会发现它的珍贵。(间接地暗示题旨,好!)因此常常责怪自己为什么不在失去之前好好把握,重视它们的存在。(此句删去为好,能让开篇更简洁。) 怎能忘记啊!在姐姐没去上大学之前,我们俩几乎是形影不离,无话不谈。

微笑是剂良药

我变了。以前的我总爱把内心的情绪反映在脸上,而如今的我总是把每一丝微笑带给我的三十一位孩子。 我的这种变化来自于我班的小佳佳。他是三十一位孩子中个子最小的一个。大人们的溺爱养成了他任性、执拗、倔犟的性格。小佳佳的这一性格在那天中午暴露无遗。

西定府乡果断清退超编人员

西定府乡果断清退超编人员河北省三河市西定府乡是一个只有８个村的小乡，而乡政府机关工作人员高达７３人，其中半脱产干部４０人。这些半脱产干部每年所需工资和办公经费近１２万元，直接和间接地加重了农民负担。为了使农民负担降下来，西定府乡本着果断清退，妥善安置...

An Evidence of Aerosol Indirect Effect on Stratus Clouds from the Integrated Ground-Based Measurements at the ARM Shouxian Site

The aerosol effect on clouds was explored using remote sensing of aerosol and cloud data at Shouxian, China. Non-precipitation, ice-free, and overcast clouds were firstly chosen by a combination of sky im- ages from the Total Sky Imager （TSI）, cloud base heights from the Ceilometer, and vertical temperature profiles from the Balloon-Borne Sounding System （BBSS）. Six cases were chosen in summer, and seven in autumn. The averaged cloud effective radii （re）, cloud optical depth （COD）, aerosol total light scattering coefficient （a）, and liquid water path （LWP） are, respectivey, 6.47 μm, 35.4, 595.9 mm-1, 0.19 mm in summer, and 6.07 μm, 96.0, 471.7 mm-1, 0.37 mm in autumn. The correlation coefficient between re and tc was found to change from negative to positive value as LWP increases.

Fault diagnosis in neutral point indirectly grounded system basedon information fusion

In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sources of information, including line current, line voltage, zero sequence current and voltage, and quintic harmonic wave component. This method is testified through the simulation of Matlab. Simulation results show that the precision and reliability of the detection has been greatly increased.

Effect of airplane transport of donor livers on post-liver transplantation survival

AIM To evaluate the effect of long haul airplane transport of donor livers on post-transplant outcomes. METHODS A retrospective cohort study of patients who received a liver transplantation was performed in Perth, Australia from 1992 to 2012. Donor and recipient characteristics information were extracted from Western Australian liver transplantation service database. Patients were followed up for a mean of six years. Patient and graft survival were evaluated and compared between patients who received a local donor liver and those who received an airplane transported donor liver. Predictors of survival were determined by univariate and multivariate analysis using cox regression.RESULTS One hundred and ninety-three patients received alocal donor liver and 93 patients received an airplane transported donor liver. Airplane transported livers had a significantly lower alanine transaminase(mean: 45 U/L vs 84 U/L, P = 0.035), higher donor risk index(mean: 1.88 vs 1.42, P < 0.001) and longer cold ischemic time(CIT)(mean: 10.1 h vs 6.4 h, P < 0.001). There was a weak correlation between CIT and transport distance(r2 = 0.29, P < 0.001). Mean follow up was six years and 93 patients had graft failure. Multivariate analysis found only airplane transport retained significance for graft loss(HR = 1.92, 95%CI: 1.16-3.17). One year graft survival was 0.88 for those with a local liver and was 0.71 for those with an airplane transported liver. One year graft loss was due to primary graft non-function or associated with preservation injury in 20.8% of recipients of an airplane transported liver compared with 4.6% in those with a local liver(P = 0.027). CONCLUSION Airplane transport of donor livers was independently associated with reduced graft survival following liver transplantation.

Indirect Radiative and Climatic Effects of Sulfate and Organic Carbon Aerosols over East Asia Investigated by RIEMS

The indirect radiative and climatic effects of sulfate and organic carbon aerosols over East Asia were investigated using a Regional Integrated Environment Model System (RIEMS) with an empirical aerosol-cloud parameterization.The first indirect radiative forcing was negative and ranged from-9-0 W m-2 in the domain.The maximum cooling,up to-9 W m-2,occurred in the Chongqing District in winter,whereas the cooling areas were larger during summer than in winter.Organic carbon (OC) aerosols were more abundant in winter than in summer,whereas the sulfate concentration during summer was much higher than during winter.The concentrations of sulfate and OC were comparable in winter,and sulfate played a dominant role in determining indirect radiative forcing in summer,whereas in winter,both sulfate and OC were important.The regional mean indirect radiative forcings were-0.73 W m-2 and-0.41 W m-2 in summer and winter,respectively.The surface cooling caused by indirect effects was more obvious in winter than that in summer.The ground temperature decreased by ～1.2 K in most areas of eastern China in winter,whereas in summer,the temperature decreased (～-1.5 K) in some regions,such as the Yangtze River region,but increased (～0.9 K) in the areas between the Yellow and Yangtze Rivers.In winter,the precipitation decreased by 0-6 mm in most areas of eastern China,but in summer,alternating bands of increasing (up to 80 mm) and decreasing (～-80 mm) precipitation appeared in eastern China.

Departure from Indigenous Land Use System and the Consequential Impacts： A Case of Cuvelai Basin, North-Central Namibia

The Cuvelai Basin of north-central Namibia consists of unique seasonal wetlands made up of shallow pans locally known as Iishana （Oshana, singular） which form ephemeral network systems. The basin has relatively fertile soils encouraging human settlements. More than 40% of the country＇s population resides in the basin. Early settlers in the basin utilized indigenous knowledge to develop land use systems that were in harmony with biophysical characteristics of the area. Over the years, there has been a departure from these indigenous land use systems resulting in land management problems. A desktop study coupled with field observations was conducted to describe the indigenous land use systems of the Owambo people living in the basin, and to determine factors behind the departure and consequential impacts of this departure on sustainability of land uses. Possible ways of preventing erosion of this indigenous knowledge were given attention. The paper recommends that the Owamboindigenous land management system needs to be embedded within government policies and regulations and should be strictly enforced. There is also a need for designing strategic basin management plans that are a combination of both scientific and indigenous knowledge.

Monitoring open water area changes in a small tarn using historical orthophotomaps and a historical bathymetric map:a case study of the Litworowy Staw lake,the High Tatras

According to scientific evidence in general, the disappearance of the Tatras tarns as a result of external geomorphological processes has been accepted since the long term analyses of lake sediments and peat bogs, geomorphological mapping, geophysical measurements(– all indirect methods). It is paradoxical that the direct cartographic evidence of such changes has not existed until now. In this paper, we evaluate shore line changes of the small mountain glacial lake in the High Tatras-Litworowy Staw lake using a multitemporal analysis of a series of historical orthophotomaps and a historical map. Over the last 100 years, the tarn has lost 46.4% of open water level area. Significant visual changes were caused by vegetation growth of Carex species(sedges) on the water's surface. The accumulation of fine sediments and dead plant residues in the tarn basin create suitable conditions for this process, all together causing the tarn to become more shallow.

Temporal and spatial characteristics of harmful algal blooms in Qingdao Waters,China

Qingdao waters,including both the semi-enclosed Jiaozhou Bay(JB) and the adjacent water out of JB(OJB),have been the areas that are most frequently affected by harmful algal blooms(HABs) in the western Yellow Sea(west of 124°E).In this research,HAB occurrences in Qingdao waters from 1990 to 2009 were investigated using spatial tools in geographic information system(GIS) and are discussed in terms of their connection to temporal variation.Additionally,the effects of each HAB occurrence were further evaluated using a simple model.The calculated results were then visualized using a GIS software to indicate the effects of HABs in Qingdao waters during the entire period.As a result,the OJB was proven to be responsible for the frequent HAB occurrences in Qingdao waters after 2000,although JB was traditionally believed to be the principle source of HAB occurrences in Qingdao waters.In addition,increasing nitrogen and N/P structure imbalance were essential for increasing HAB occurrences in Qingdao waters throughout the entire period,especially for the recent HAB occurrences in the OJB.The results of this research would improve the current understanding on HAB occurrences in Qingdao waters,which would benefit HAB monitoring and the implementation of a control strategy in China as well.

Coordinated scheduling model for intermodal transit hubs based on GI/M^K/1 queuing system

Coordinated scheduling of multimode plays a pivotal role in the rapid gathering and dissipating of passengers in transport hubs. Based on the survey data, the whole-day reaching time distribution at transfer points of passengers from the dominant mode to the connecting mode was achieved. A GI/M K/1 bulk service queuing system was constituted by putting the passengers' reaching time distribution as the input and the connecting mode as the service institution. Through queuing theory, the relationship between average queuing length under steady-state and headway of the connecting mode was achieved. By putting the minimum total cost of system as optimization objective, the headway as decision variable, a coordinated scheduling model of multimode in intermodal transit hubs was established. At last, a dynamic scheduling strategy was generated to cope with the unexpected changes of the dominant mode. The instance analysis indicates that this model can significantly reduce passengers' queuing time by approximately 17% with no apparently increase in departure frequency, which provides a useful solution for the coordinated scheduling of different transport modes in hubs.

The Articulations of the In-between Realm in Sardinia

At the base of the reflection developed in this research work, there is the concept of habitat as a system, as an articulated ＂whole＂ that cannot be explained with the simple sum of its parts. The concept of habitat, in fact, implies issues of dialectic spaces, in other words, those settings that can be defined as relational subsystems within the urban/domestic scale. This essay has its roots in the CIAM （Congr^s International d＇Architecture Moderne （in English： International Congress of Modem Architecture）） of 1953, during which the complementarity of the outside space next to the dwelling and its relevance within the project discipline, have been affirmed. In particular, assimilating the lesson of Aldo van Eyck, this work investigates the deepest issues of the concept of threshold. The analysis makes use of the work-tools of critical reading and comparison between urban and rural habitats, with different density levels, whose relational fabrics have been layering over time permeable ＂thicknesses＂ which articulate complex threshold spatial configurations.

An Improved Direction Relation Detection Model for Spatial Objects

Direction is a common spatial concept that is used in our daily life. It is frequently used as a selection condition in spatial queries. As a result, it is important for spatial databases to provide a mechanism for modeling and processing direction queries and reasoning. Depending on the direction relation matrix, an inverted direction relation matrix and the concept of direction pre- dominance are proposed to improve the detection of direction relation between objects. Direction predicates of spatial systems are also extended. These techniques can improve the veracity of direction queries and reasoning. Experiments show excellent efficiency and performance in view of direction queries.