Research and Demonstration of Direct Air-Cooling System for 600-MW Fossil-Fired Power Plants

Given the distribution feature of resources such as coal and water, the requirements for the development of Chinese power industry, and the fact of monopoly by foreign companies, it is very necessary and significant to independently research and develop air-cooling technologies. Through experimental research, simulative calculation, process and equipment development, field tests and a demonstration project, the design and operation technologies for air-cooling system are grasped and relevant key equipment is developed. The results of the demonstration project show that the technical indicators for the air-cooling system have met or exceeded the design requirements. Part of the research results have been incorporated into the relevant national design standards. The technologies developed have been applied to more than 23 sets of thermal power units of or above 600 MW in China.

Thermodynamic Simulation of CCP in Air-Cooled Heat Pump Unit with HFCs and CO₂Trans-Critical

The exergy analysis and finite time thermodynamic methods had been employed to analyze the compound condensation process (CCP). It was based on the air-cooling heat pump unit. The cooling capacity of the chiller unit is about 1 kW, and the work refrigerant is R22/R407C/R410A/CO2. The MATLAB/SIMULINK software was employed to build the simulation model. The thermodynamic simulation model is significant for the optimization of parameters of the unit, such as condensation and evaporation temperature and mass flow of the sanitary hot water and size of hot water storage tank. The COP of the CCP of R410A system is about 3% - 5% higher than the CCP of the R22 system, while CCP of the R407C system is a little lower than the CCP of R22 system. And the CCP of CO2 trans-critical system has advantage in the hot supply mode. The simulation method provided a theoretical reference for developing the production of CCP with substitute refrigerant R407C/R410A/CO2.

Influence of thermal flow field of cooling tower on recirculation ratio of a direct air-cooled system for a power plant

In order to get thermal flow field of direct air-cooled system,the hot water was supplied to the model of direct air-cooled condenser(ACC). The particle image velocimetery (PIV) experiments were carried out to get thermal flow field of a ACC under different conditions in low velocity wind tunnel,at the same time,the recirculation ratio at cooling tower was measured,so the relationship between flow field characteristics and recirculation ratio of cooling tower can be discussed. From the results we can see that the flow field configuration around cooling tower has great effects on average recirculation ratio under cooling tower. The eddy formed around cooling tower is a key reason that recirculation produces. The eddy intensity relates to velocity magnitude and direction angle,and the configuration of eddy lies on the geometry size of cooling tower. So changing the flow field configuration around cooling tower reasonably can decrease recirculation ratio under cooling tower,and heat dispel effect of ACC can also be improved.

Designing a Protection Scheme in Micro-Grid Systems with DG Using Central Protection Unite and Multiple Setting Group Protection Relays

Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.

Signed Directed Graph and Qualitative Trend Analysis Based Fault Diagnosis in Chemical Industry

In the past 30 years,signed directed graph(SDG) ,one of the qualitative simulation technologies,has been widely applied for chemical fault diagnosis.However,SDG based fault diagnosis,as any other qualitative method,has poor diagnostic resolution.In this paper,a new method that combines SDG with qualitative trend analysis(QTA) is presented to improve the resolution.In the method,a bidirectional inference algorithm based on assumption and verification is used to find all the possible fault causes and their corresponding consistent paths in the SDG model.Then an improved QTA algorithm is used to extract and analyze the trends of nodes on the consis-tent paths found in the previous step.New consistency rules based on qualitative trends are used to find the real causes from the candidate causes.The resolution can be improved.This method combines the completeness feature of SDG with the good diagnostic resolution feature of QTA.The implementation of SDG-QTA based fault diagno-sis is done using the integrated SDG modeling,inference and post-processing software platform.Its application is illustrated on an atmospheric distillation tower unit of a simulation platform.The result shows its good applicability and efficiency.

Video versus direct laryngoscopy on successful firstpass endotracheal intubation in ICU patients

BACKGROUND: Airway management in intensive care unit(ICU) patients is challenging. The aim of this study was to compare the rate of successful first-pass intubation in the ICU by using the direct laryngoscopy(DL) and that by using the video laryngoscopy(VL).METHODS: A randomized, non-blinded trial comparing first-pass success rate of intubation between VL and DL was performed. Patients were recruited in the period from August 2014 to August 2016. All physicians working at ICU received hands-on training in the use of the video and direct laryngoscope. The primary outcome measure was the first-pass intubation success. RESULTS: A total of 163 ICU patients underwent intubation during the study period(81 patients in VL group and 82 in DL group). The rate of successful first-pass intubation was not significantly different between the VL and the DL group(67.9% vs. 69.5%, P=0.824). Moreover, the overall intubation success and total number of attempts to achieve intubation success did not differ between the two groups. In patients with successful first-pass intubation, the median duration of the intubation procedure did not differ between the two groups. The Cormack-Lehane grades and the percentage of glottic opening score were similar, and no significant differences were found between the two groups. There were no statistical differences between the VL and the DL group in intubation complications(all P>0.05). CONCLUSION: Among ICU patients requiring intubation, there was no significant difference in the rate of successful first-pass intubation between VL and DL.

Palliative care for acute kidney injury patients in the intensive care unit

Patients with acute kidney injury(AKI) in the intensive care unit(ICU) are often suitable for palliative care due to the high symptom burden. The role of palliative medicine in this patient population is not well defined and there is a lack of established guidelines to address this issue. Because of this,patients in the ICU with AKI deprived of the most comprehensive or appropriate care. The reasons for this are multifactorial including lack of palliative care training among nephrologists. However,palliative care in these patients can help alleviate symptoms,improve quality of life,and decrease suffering. Palliative care physicians can determine the appropriateness and model of palliative care. In addition to shared decision-making,advance directives should be established with patients early on,with specific instructions regarding dialysis,and those advance directives should be respected.

Impact of utilization of hepatitis C positive organs in liver transplant:Analysis of united network for organ sharing database

BACKGROUND The utility of hepatitis C virus(HCV)organs has increased after the Food and Drug Administration approval of direct acting anti-viral(DAA)medications for the HCV treatment.The efficacy of DAA in treating HCV is nearly 100%.AIM To analyze the United Network for Organ Sharing(UNOS)database to compare the survival rates between the hepatitis C positive donors and negative recipients and hepatitis C negative donors and recipients.METHODS We analyzed the adult patients in UNOS database who underwent deceased donor liver transplant from January 2014 to December 2017.The primary endpoint was to compare the survival rates among the four groups with different hepatitis C donor and recipient status:(Group 1)Both donor and recipient negative for HCV(Group 2)Negative donor and positive recipient for HCV(Group 3)Positive donor and negative recipient for HCV(Group 4)Both positive donor and recipient for HCV.SAS 9.4 software was used for the data analysis.Kaplan Meier log rank test was used to analyze the estimated survival rates among the four groups.RESULTS A total of 24512 patients were included:Group 1:16436,Group 2:6174,Group 3:253 and Group 4:1649.The 1-year(Group 1:91.8%,Group 2:92.12%,Group 3:87%,Group 4:92.8%),2-year(Group 1:88.4%,Group 2:88.1%,Group 3:84.3%,Group 4:87.5%),3-year(Group 1:84.9%,Group 2:84.3%,Group 3:75.9%,Group 4:83.2%)survival rates showed no statistical significance among the four groups.Kaplan Meier log rank test did not show any statistical significance difference in the estimated survival rates between Group 3 vs all the other groups.CONCLUSION The survival rates in hepatitis C positive donors and negative recipients are similar as compared to both hepatitis C negative donors and recipients.This could be due to the use of DAA therapy with cure rates of nearly 100%.This study supports the use of hepatitis C positive organs in the selected group of recipients with and without HCV infection.Further long-term studies are needed to further validate these findings.

Influence of antibiotic-regimens on intensive-care unit-mortality and liver-cirrhosis as risk factor

AIM: To assess the rate of infection, appropriateness of antimicrobial-therapy and mortality on intensive care unit(ICU). Special focus was drawn on patients with liver cirrhosis.METHODS: The study was approved by the local ethical committee. All patients admitted to the Internal Medicine-ICU between April 1, 2007 and December 31, 2009 were included. Data were extracted retrospectively from all patients using patient charts and electronic documentations on infection, microbiological laboratory reports, diagnosis and therapy. Due to the large hepatology department and liver transplantation center, special interest was on the subgroup of patients with liver cirrhosis. The primary statistical-endpoint was the evaluation of the influence of appropriate versusinappropriate antimicrobial-therapy on in-hospitalmortality.RESULTS: Charts of 1979 patients were available. The overall infection-rate was 53%. Multiresistantbacteria were present in 23% of patients with infection and were associated with increased mortality(p < 0.000001). patients with infection had significantly increased in-hospital-mortality(34% vs 17%, p < 0.000001). Only 9% of patients with infection received inappropriate initial antimicrobial-therapy, no influence on mortality was observed. Independent risk-factors for in-hospital-mortality were the presence of septicshock, prior chemotherapy for malignoma and infection with pseudomonas spp. Infection and mortality-rate among 175 patients with liver-cirrhosis was significantly higher than in patients without liver-cirrhosis. Infection increased mortality 2.24-fold in patients with cirrhosis. patients with liver cirrhosis were at an increased risk to receive inappropriate initial antimicrobial therapy.CONCLUSION: The results of the present study report the successful implementation of early-goal-directed therapy. Liver cirrhosis patients are at increased risk of infection, mortality and to receive inappropriate therapy. Increasing burden are multiresistant-bacteria.

Unit cost of CT scan and MRI at a large tertiary care teaching hospital in North India

Imaging department is an important department of a hospital contributing directly to patient care, providing diagnostic support to all specialties which cannot practice efficiently without their support. Hospital administrators are looking for newer tools to control costs without affecting the quality of patient care. It is well known that the escalation of costs for advanced technology has been dramatic and it has been labeled as one of the culprits for great increase in healthcare costs. A prospective study for a period of six months was carried out for calculation of unit cost of radiological investigations CT head, CT chest, CT abdomen and MRI. Unit costs were computed under direct and indirect costs. The actual cost incurred by the hospital on CT head was Rupees 581.40 (US $10.89), CT abdomen Rupees 2339.20 (US $43.83), CT chest Rupees 2339.20 (US $43.83), and MRI Rupees 4497.50 (US $84.28). However, in the hospital patients are charged Rupees 900 (US $16.86) for CT head, Rupees 1200 (US $22.48) for CT abdomen, Rupees 1200 (US $22.48) for CT chest and Rupees 2500 (US $46.85) for MRI. There is a substantial loss of revenue because of subsidies provided to patients in a tertiary care teaching hospital which needs revision of charges.

The Experimental Investigation of Recirculation of Air-Cooled System for a Large Power Plant

The paper introduces thermal buoyancy effects to experimental investigation of wind tunnel simulation on direct air-cooled condenser for a large power plant. In order to get thermal flow field of air-cooled tower, PIV experiments are carried out and recirculation ratio of each condition is calculated. Results show that the thermal flow field of the cooling tower has great influence on the recirculation under the cooling tower. Ameliorating the thermal flow field of the cooling tower can reduce the recirculation under the cooling tower and improve the efficiency of air-cooled condenser also.

Development of a Cell-based Model to Derive Direct Runoff Hydrographs for Ungauged Mountainous Basins

A model to derive direct runoff hydrograph for an ungauged basin using the physical properties of the basin is presented. The basin is divided into grid cells and canal elements. Overland flow is generated from each grid cell of the basin by application of continuous effective rainfall of I mm/hr to the basin, The flow generated is routed through downstream grid cells and the canal elements using the kinematic wave approach. The travel time for direct runoff from each grid cell to the basin outlet is calculated and the S-curve is derived for the basin. The S-curve is used to derive the unit hydrograph of a given duration for the basin. The model, referred as Cell-basin model was applied to the Upper Kotmale Basin in Sri Lanka and the model predictions of direct runoff hydrographs for rainfall events agreed with the observations to a reasonable accuracy. Comparison of the unit hydrographs obtained from the model and from the conventional Snyder＇s synthetic unit hydrograph using regionalized parameters assuming the basin as an ungauged basin, with the unit hydrograph derived from the observations showed that the model predicted unit hydrograph was more suitable than that obtained by Snyder＇s method for Sri Lankan up country basins. Thus, the present model is a useful tool to obtain direct runoff hydrograph for ungauged basins.

传承创新中华优秀传统文化与统战工作的双向赋能

文化认同是民族团结的根脉,是统战工作和建设中华民族现代文明的重要内容。新时代统战工作与中华优秀传统文化的传承创新具有“双向赋能”的紧密联系。具体而言,“天下为公”思想有利于提升统战工作的战略定位,“和合文化”观念有利于深化统战工作的理念原则,进而从多个维度提升新时代统战工作的“势能”。在实践中,认同主体价值观念的代际变迁推进统战工作赋予传统文化时代性元素,认同建构空间的扩展促使统战工作深入挖掘传统文化的包容性内涵,进而从多个角度赋予统战工作对中华优秀传统文化进行创造性转化和创新性发展的强大“动能”。新时代的统战工作必将成为传承创新中华优秀传统文化的重要场域。

基于CNN-BiGRU-Attention的短期电力负荷预测

针对目前电力负荷数据随机性强,影响因素复杂,传统单一预测模型精度低的问题,结合卷积神经网络(Convolutional neural network,CNN)、双向门控循环单元(Bi-directional gated recurrent unit,BiGRU)以及注意力机制(Attention)在短期电力负荷预测上的不同优点,提出一种基于CNN-BiGRU-Attention的混合预测模型。该方法首先通过CNN对历史负荷和气象数据进行初步特征提取,然后利用BiGRU进一步挖掘特征数据间时序关联,再引入注意力机制,对BiGRU输出状态给与不同权重,强化关键特征,最后完成负荷预测。试验结果表明,该模型的平均绝对百分比误差(Mean absolute percentage error,MAPE)、均方根误差(Root mean square error,RMSE)、判定系数(R-square,R~2)分别为0.167%、0.057%、0.993,三项指标明显优于其他模型,具有更高的预测精度和稳定性,验证了模型在短期负荷预测中的优势。

早期目标导向活动对机械通气患者短期预后的应用研究

目的探讨早期目标导向活动在重症加强护理病房(ICU)机械通气患者中应用的短期预后效果。方法采用便利抽样法,选取76例机械通气患者作为研究对象,以病区为单位,入住ICU A区的38例患者为对照组,实施常规康复护理方案;入住ICU B区的38例患者为实验组,采用Richmond躁动-镇静评分、标准化5问题问卷、ICU活动量表评估研究对象镇静程度、配合程度及ICU活动能力,实施早期目标导向活动。观察2组患者肌力及握力水平、ICU活动能力、机械通气时间及ICU住院时间。结果干预第4 d及出科前实验组肌力、握力及出科前的活动能力得分高于对照组(P<0.05);实验组机械通气时间及ICU住院时间短于对照组(P<0.05)。结论早期目标导向活动有助于提高机械通气患者的肌力、活动能力,缩短ICU停留时间,改善患者短期预后。未来可进一步随访,探究早期目标导向活动的远期效果,为早期目标导向活动的推广及应用提供临床指导。

我国图书情报硕士专业学位培养单位招生方向设置研究

招生方向是课程设置和研究生培养的前提与基础,既反映学科研究的热点方向,又体现研究生教育的重点。文章通过调查研究,对74个MLIS培养单位的招生方向设置现状进行了全面分析,发现招生方向有传统图情档类、交叉融合类、发展探索类三大类,招生方向存在设置不合理、特色不明显、发展不平衡等问题,提出合理设置招生方向、规范名称,优化建设招生方向、突显特色,携手发展共创未来、交叉融合等优化对策,以期为MLIS培养单位招生方向设置提供借鉴与参考,促进MLIS研究生教育的发展。

基于BO-BiGRU-Attention短期电力负荷预测

电力系统的可靠供应对于工业、商业和居民的生活至关重要。为了满足电力需求并维持电力系统的稳定运行,提高短期电力负荷预测的准确性和可靠性尤为关键;针对负荷数据存在复杂的非线性特性,该文提出一种基于贝叶斯优化算法的双向门控循环单元和注意力机制(BO-BiGRU-Attention)的混合预测模型对短期电力负荷进行精准预测。首先,使用Min-Max Normalization方法对负荷数据进行归一化处理。其次,利用BiGRU网络捕获序列中的长期依赖关系和上下文信息,结合注意力机制,通过在输入序列的不同部分给予不同的权重,从而突出关键特征。最后,针对BiGRU-Attention模型的超参数难以选取最优解的问题,引入贝叶斯优化算法对BiGRU-Attention模型的超参数进行寻优,完成短期电力负荷的预测。采用印度北部某地区的电力负荷数据进行预测分析,仿真结果表明,BO-BiGRU-Attention网络表现优于其他模型,各误差评价指标最小,其中MAE、RMSE和MAPE分别为56.67,73.49和1.16%,预测精度达到了99.47%。

银额盆地构造单元划分与油气勘探方向

银额盆地是中国陆上油气勘探程度较低的含油气盆地之一,近年来其油气勘探取得明显进展,但复杂的地质结构在一定程度上制约了对盆地内构造单元的认识,导致油气勘探方向不明。为明确下一步油气勘探方向,结合该盆地钻井、地震和重力勘探等资料,落实了盆地内主要断裂的分布,划分了中生代构造单元,编制了中生界底界埋深图,明确了中生代凹陷的分布特征,最后指出了盆地油气勘探方向。研究结果表明:①银额盆地中生界与前中生界的不整合特征明显,上、下层在岩性组合和构造样式上明显不同,下构造层发育一系列复式褶皱和冲断构造,上构造层则由一系列近东西向、北东向断陷群构成;②盆地主要被红石山断裂带、阿尔金断裂带(或分支)、恩格尔乌苏断裂带和查干础鲁断裂带分隔,形成多个隆起和坳陷,坳陷又由多个凹陷和凸起构成;③油气主要在中生代箕状断陷的缓坡下部聚集,早期成藏后遭受抬升、调整,现今埋深相对较浅的凹陷值得关注,油气有利勘探面积超过5×10^(4) km^(2);④针对以粒间纳米级孔为主的微孔隙厚层泥岩,可以按照非常规油气藏勘探思路系统评价,探索泥岩的油气勘探潜力。结论认为,研究成果对深化认识银额盆地基础构造特征,进一步促进银额盆地油气勘探方向认识和推动盆地的油气勘探开发进程具有重要意义。

基于CNN-BiGRU的高压直流输电线路故障识别

针对高压直流(high voltage direct current,HVDC)输电线路故障暂态行波具有时序性和强非线性的特点,导致高过渡电阻情况下故障识别率低的问题,提出基于卷积神经网络(convolutional neural networks,CNN)和双向循环门单元(bidirectional gate recurrent unit,BiGRU)的HVDC输电线路故障识别方法。首先,采用故障后整流侧的双极暂态电流行波作为特征向量,利用CNN提取全局特征,并从中剔除噪声和不稳定成分,完成对数据的降维处理。然后,采用BiGRU来捕获CNN提取到特征的前后时间信息,进一步提取数据中的时序特征,以实现HVDC输电线路故障识别。仿真结果表明:该方法可在不同故障地点以及不同过渡电阻下对单极接地、双极短路、雷击故障、雷击干扰共四种故障实现准确识别,可靠性高,具有较强的耐受过渡电阻能力,同时具备一定的抗噪性能。

基于条形卷积和上下文感知的近海水产养殖提取方法

利用中等分辨率遥感影像,针对近海养殖区边界模糊、筏式和网箱养殖存在类间干扰等现象,以ResUnet模型为基础,提出一种带有条形卷积模块和上下文感知单元的MSUResUnet模型,以提高模型的特征提取能力,改善近海水产养殖提取任务中出现的漏提和粘连等问题.模型中利用条形池化模块增强编码层与解码层信息的交互,引入条形卷积模块增强对水产养殖线性特征的捕捉能力,通过增加上下文感知单元获取水产养殖区丰富的多尺度上下文信息.在Sentinel-2 MSI数据上的实验结果表明,参与比对的6个模型中,MSUResUnet模型精度最优,其Kappa系数、 MIoU、 OA和F1分数分别达到了89.17%、 84.33%、 96.38%和91.19%;MSUResUnet在养殖较密集的兴化湾、三沙湾和罗源湾附近海域均获得较高精度,具有较强的特征提取和抗干扰能力,能够满足高精度的大范围中等分辨率影像近海水产养殖信息提取需求.