Predicting potential invasion risks of Leucaena leucocephala(Lam.)de Wit in the arid area of Saudi Arabia

The presence of invasive plant species poses a substantial ecological impact,thus comprehensive evaluation of their potential range and risk under the influence of climate change is necessary.This study uses maximum entropy(MaxEnt)modeling to forecast the likelihood of Leucaena leucocephala(Lam.)de Wit invasion in Saudi Arabia under present and future climate change scenarios.Utilizing the MaxEnt modeling,we integrated climatic and soil data to predict habitat suitability for the invasive species.We conducted a detailed analysis of the distribution patterns of the species,using climate variables and ecological factors.We focused on the important influence of temperature seasonality,temperature annual range,and precipitation seasonality.The distribution modeling used robust measures of area under the curve(AUC)and receiver-operator characteristic(ROC)curves,to map the invasion extent,which has a high level of accuracy in identifying appropriate habitats.The complex interaction that influenced the invasion of L.leucocephala was highlighted by the environmental parameters using Jackknife test.Presently,the actual geographic area where L.leucocephala was found in Saudi Arabia was considerably smaller than the theoretical maximum range,suggesting that it had the capacity to expand further.The MaxEnt model exhibited excellent prediction accuracy and produced reliable results based on the data from the ROC curve.Precipitation and temperature were the primary factors influencing the potential distribution of L.leucocephala.Currently,an estimated area of 216,342 km^(2)in Saudi Arabia was at a high probability of invasion by L.leucocephala.We investigated the potential for increased invasion hazards in the future due to climate change scenarios(Shared Socioeconomic Pathways(SSPs)245 and 585).The analysis of key climatic variables,including temperature seasonality and annual range,along with soil properties such as clay composition and nitrogen content,unveiled their substantial influence on the distribution dynamic of L.leucocephala.Our findings indicated a significant expansion of high risk zones.High-risk zones for L.leucocephala invasion in the current climate conditions had notable expansions projected under future climate scenarios,particularly evident in southern Makkah,Al Bahah,Madina,and Asir areas.The results,backed by thorough spatial studies,emphasize the need to reduce the possible ecological impacts of climate change on the spread of L.leucocephala.Moreover,the study provides valuable strategic insights for the management of invasion,highlighting the intricate relationship between climate change,habitat appropriateness,and the risks associated with invasive species.Proactive techniques are suggested to avoid and manage the spread of L.leucocephala,considering its high potential for future spread.This study enhances the overall comprehension of the dynamics of invasive species by combining modeling techniques with ecological knowledge.It also provides valuable information for decision-making to implement efficient conservation and management strategies in response to changing environmental conditions.

Efficacy of a Diabetes Specific Nutritional Supplement (DSNS) on Glycemic Response in Prediabetic Adults: A Two-Armed, Open-Labelled Randomized Controlled Study

It is well known that Diabetes Specific Nutritional Supplements (DSNSs) are linked to improved glycemic control in individuals with diabetes. However, data on efficacy of DSNSs in prediabetics is limited. This was a two-armed, open-labelled, randomized controlled six-week study on 199 prediabetics [30 - 65 years;Glycosylated Hemoglobin (HbA1c) 5.7% - 6.4% and/or Fasting Blood Glucose (FBG) 100-125 mg/dl]. Two parallel phases were conducted: Acute Blood Glucose Response (ABGR) and Intervention phase. Prediabetic participants were randomized into test (n = 100) and control (n = 99). The primary objective was to assess the ABGR of DSNS versus an isocaloric snack, measured by incremental Area under the Curve (iAUC). Test and control received 60 g of DSNS and 56 g of isocaloric snack (cornflakes) respectively, both in 250 ml double-toned milk on visit days 1, 15, 29 and 43. Postprandial Blood Glucose (PPG) was estimated at 30, 60, 90, 120, 150 and 180 minutes. During the 4 weeks intervention phase, the test group received DSNS with lifestyle counselling (DSNS + LC) and was compared with the control receiving lifestyle counselling alone (LC alone). Impact was studied on FBG, HbA1C, anthropometry, body composition, blood pressure, nutrient intake, and physical activity. The impact of DSNS was also studied using CGM between two 14-day phases: CGM1 baseline (days 1 - 14) and CGM2 endline (days 28 - 42). DSNS showed significantly lower PPG versus isocaloric snack at 30 (p 12, and chromium were reported by DSNS + LC versus LC alone. No other significant changes were reported between groups. It may be concluded that DSNS may be considered as a snack for prediabetic or hyperglycemic individuals requiring nutritional support for improved glycemic control.

Preoperative prediction of hepatocellular carcinoma microvascular invasion based on magnetic resonance imaging feature extraction artificial neural network

BACKGROUND Hepatocellular carcinoma(HCC)recurrence is highly correlated with increased mortality.Microvascular invasion(MVI)is indicative of aggressive tumor biology in HCC.AIM To construct an artificial neural network(ANN)capable of accurately predicting MVI presence in HCC using magnetic resonance imaging.METHODS This study included 255 patients with HCC with tumors<3 cm.Radiologists annotated the tumors on the T1-weighted plain MR images.Subsequently,a three-layer ANN was constructed using image features as inputs to predict MVI status in patients with HCC.Postoperative pathological examination is considered the gold standard for determining MVI.Receiver operating characteristic analysis was used to evaluate the effectiveness of the algorithm.RESULTS Using the bagging strategy to vote for 50 classifier classification results,a prediction model yielded an area under the curve(AUC)of 0.79.Moreover,correlation analysis revealed that alpha-fetoprotein values and tumor volume were not significantly correlated with the occurrence of MVI,whereas tumor sphericity was significantly correlated with MVI(P<0.01).CONCLUSION Analysis of variable correlations regarding MVI in tumors with diameters<3 cm should prioritize tumor sphericity.The ANN model demonstrated strong predictive MVI for patients with HCC(AUC=0.79).

Gut microbiota predicts the diagnosis of ulcerative colitis in Saudi children

BACKGROUND Ulcerative colitis(UC)is an immune-mediated chronic inflammatory condition with a worldwide distribution.Although the etiology of this disease is still unknown,the understanding of the role of the microbiota is becoming increasingly strong.AIM To investigate the predictive power of the gut microbiota for the diagnosis of UC in a cohort of newly diagnosed treatment-naïve Saudi children with UC.METHODS The study population included 20 children with a confirmed diagnosis of UC and 20 healthy controls.Microbial DNA was extracted and sequenced,and shotgun metagenomic analysis was performed for bacteria and bacteriophages.Biostatistics and bioinformatics demonstrated significant dysbiosis in the form of reduced alpha diversity,beta diversity,and significant difference of abundance of taxa between children with UC and control groups.The receiver operating characteristic curve,a probability curve,was used to determine the difference between the UC and control groups.The area under the curve(AUC)represents the degree of separability between the UC group and the control group.The AUC was calculated for all identified bacterial species and for bacterial species identified by the random forest classification algorithm as important potential biomarkers of UC.A similar method of AUC calculation for all bacteriophages and important species was used.RESULTS The median age and range were 14(0.5-21)and 12.9(6.8-16.3)years for children with UC and controls,respectively,and 40%and 35%were male for children with UC and controls,respectively.The AUC for all identified bacterial species was 89.5%.However,when using the bacterial species identified as important by random forest classification algorithm analysis, the accuracy increased to 97.6%. Similarly, the AUC for all theidentified bacteriophages was 87.4%, but this value increased to 94.5% when the important bacteriophagebiomarkers were used.CONCLUSIONThe very high to excellent AUCs of fecal bacterial and viral species suggest the potential use of noninvasivemicrobiota-based tests for the diagnosis of unusual cases of UC in children. In addition, the identification ofimportant bacteria and bacteriophages whose abundance is reduced in children with UC suggests the potential ofpreventive and adjuvant microbial therapy for UC.

骨科术后患者万古霉素AUC_(0~24h)影响因素分析及预测模型研究

目的探讨万古霉素在骨科术后患者中的24 h曲线下面积(AUC_(0~24h))的影响因素,并预测分析AUC_(0~24h)较好的药代动力学模型。方法纳入新疆医科大学第六附属医院2018年1月至2022年12月进行骨科手术并使用万古霉素的患者,收集患者的基本信息、用药情况、血常规和血生化指标,分析影响骨科术后患者万古霉素AUC_(0~24h)的因素。采用一级药代动力学公式、个体化给药辅助决策系统(JPKD)和万古霉素日剂量消除率公式计算AUC_(0~24h)。结果最终纳入91例患者,结果发现胱抑素C(OR=189.168,P=0.005)和单次剂量(OR=19.160,P<0.001)是骨科术后患者万古霉素AUC_(0~24h)的独立保护因素,视黄醇结合蛋白是万古霉素AUC_(0~24h)的独立危险因素(OR=0.910,P<0.05)。通过对骨科术后患者万古霉素AUC_(0~24h)模型预测分析,JPKD软件和万古霉素日剂量消除率公式的绝对权重偏差均低于30%,JPKD软件和万古霉素日剂量消除率公式的AUC_(0~24h)与一级药代动力学公式的AUC_(0~24h)组内相关系数分别为0.781和0.524。结论胱抑素C是影响骨科术后患者万古霉素AUC_(0~24h)的重要因素,JPKD软件较万古霉素日剂量消除率公式方法更适用于预测骨科术后万古霉素AUC_(0~24h)。

Derivations of Vector Area and Volume Elements in Curved Coordinate Systems for Flux Vector Fields Helping Eye Disease

Our aim in this paper is to interest retinal eye specialists in preventing dry macula degeneration by a special flurry vector field through open or closed curved surfaces. The flux of vector fields through surfaces is based on vector element area and volume element. Therefore, we explain a few geometrical derivations of area and volume elements in curved orthogonal coordinate systems. We hope that by derivation of a spatial vector field flurry against drusen through open or closed surfaces due to the Gauss theorem might select drusen under eye retina cells without destroying the cells and prevent macula degeneration. A changed flurry of a magnetic or electric vector field through a closed line causes an electric or magnetic vector field on the surface closed by the line. We also hope that derivation by Stokes’ and Greens’ theorems, with the help of iron, might help eye cells to get in life.

地中海贫血患儿造血干细胞移植术后伏立康唑谷浓度及AUC的影响因素分析

目的分析地中海贫血患儿造血干细胞移植(HSCT)术后伏立康唑(VRZ)谷浓度(c_(min))和药时曲线下面积(AUC)的影响因素。方法选择2021年1月至2024年1月于我院接受HSCT并使用VRZ预防或治疗侵袭性真菌感染的地中海贫血患儿60例,采用高效液相色谱法测定VRZ的血药浓度并计算AUC;采用多元线性回归分析影响VRZ c_(min)、AUC的独立因素。结果共得到60例患儿的120例次VRZ c_(min),26例患儿的27例次VRZ AUC。VRZ c_(min)的中位浓度是0.31 mg/L,其中0.5~5 mg/L有46例次(38.33%),>5 mg/L有2例次(1.67%),<0.5 mg/L有72例次(60.00%);VRZ AUC的中位数是11.68 mg·h/L。患儿体重、HSCT术后时间、淋巴细胞计数以及是否合用苯妥英钠、他克莫司、环孢素对VRZ c_(min)有显著影响(P<0.05);淋巴细胞计数和是否合用苯妥英钠对VRZ AUC有显著影响(P<0.05)。结论患儿体重、HSCT术后时间、淋巴细胞计数以及是否合用苯妥英钠、他克莫司、环孢素是影响VRZ c_(min)的独立因素,淋巴细胞计数、是否合用苯妥英钠是影响VRZ AUC的独立因素。

Deep Learning-Based ECG Classification for Arterial Fibrillation Detection

The application of deep learning techniques in the medical field,specifically for Atrial Fibrillation(AFib)detection through Electrocardiogram(ECG)signals,has witnessed significant interest.Accurate and timely diagnosis increases the patient’s chances of recovery.However,issues like overfitting and inconsistent accuracy across datasets remain challenges.In a quest to address these challenges,a study presents two prominent deep learning architectures,ResNet-50 and DenseNet-121,to evaluate their effectiveness in AFib detection.The aim was to create a robust detection mechanism that consistently performs well.Metrics such as loss,accuracy,precision,sensitivity,and Area Under the Curve(AUC)were utilized for evaluation.The findings revealed that ResNet-50 surpassed DenseNet-121 in all evaluated categories.It demonstrated lower loss rate 0.0315 and 0.0305 superior accuracy of 98.77%and 98.88%,precision of 98.78%and 98.89%and sensitivity of 98.76%and 98.86%for training and validation,hinting at its advanced capability for AFib detection.These insights offer a substantial contribution to the existing literature on deep learning applications for AFib detection from ECG signals.The comparative performance data assists future researchers in selecting suitable deep-learning architectures for AFib detection.Moreover,the outcomes of this study are anticipated to stimulate the development of more advanced and efficient ECG-based AFib detection methodologies,for more accurate and early detection of AFib,thereby fostering improved patient care and outcomes.

基于ANSYS Workbench飞机有限元仿真分析

飞机在空中的飞行状态对于航空飞行的安全有着不可忽视的影响。根据曲面梯形机翼飞机的特点,运用UG NX软件对其进行了三维建模,并导入至ANSYS Workbench中,从而进行有限元静力学仿真研究。探讨了不同材料的曲面梯形机翼形状的飞机在飞行过程中的总变形图和应力分布图。结合总变形图和应力分布图,仿真结果表明,机翼的部分有较大的变形,最危险的地方存在于机翼的连接处和机翼边缘,故此需要对其材料进行调整或者优化飞机的结构,优化后的结构能够满足飞机飞行的要求。并进一步对结构钢材料和铝合金材料的模型进行了对比,发现采用结构钢的飞机机翼应变分布的更合理,满足飞行的作业要求。

血清CEA、TK1、CA724、PGⅠ/PGⅡ联合检验在早期胃癌中的诊断效能

目的 分析血清癌胚抗原(CEA)、胸苷激酶(TK1)、糖类抗原(CA)724、胃蛋白酶原I(PGI)/PGⅡ联合检测诊断早期胃癌的效果。方法 将2021年8月-2022年8月本院收治的89例早期胃癌患者纳入观察组;另将同期本院收治的90例胃良性病变患者纳入对照组;并将同期于本院行健康体检的85例健康人群纳入健康组,采集三组静脉血,检测对比其血清CEA、TK1、CA724、PGⅠ/PGⅡ的差异;另绘制受试者工作曲线(ROC),分析CEA、TK1、CA724、PGⅠ/PGⅡ联合检测诊断早期胃癌的效能。结果 观察组CEA为(19.84±2.23)ng/m L、TK1为(3.97±0.52)pmol/L、CA724为(42.89±5.31)U/m L,高于对照组的(2.57±0.26)ng/m L、(1.18±0.23)pmol/L、(4.15±0.57)U/m L与健康组的(2.36±0.35)ng/m L、(1.16±0.27)pmol/L、(3.87±0.46)U/m L,PGⅠ/PGⅡ为(2.31±0.26),低于对照组的(4.89±0.75)与健康组的(5.31±0.96),差异有统计学意义(P<0.05);ROC结果显示:CEA、TK1、CA724、PGⅠ/PGⅡ联合检测诊断早期胃癌的曲线下面积(AUC)为0.947(95%CI:0.910-0.984),高于几者单独检测的0.846(95%CI:0.787-0.904)、0.862(95%CI:0.801-0.922)、0.867(95%CI:0.814-0.919)、0.873(95%CI:0.819-0.928)。结论 早期胃癌患者机体内的CEA、TK1、CA724呈异常高表达,PGⅠ/PGⅡ呈异常低表达,四者联合可有效提高早期胃癌的诊断准确度,为临床提供可靠的依据,临床应用价值较高,值得大力推行。

Glycemic Indices of Multiple Oral Nutritional Supplements: A Randomized Cross-Over Study in Indian Adults

Background: A randomized cross-over study was conducted to assess the glycemic index (GI) of seven Oral Nutritional Supplements (ONSs). These ONSs are designed to support the nutritional requirements of different age-groups, physiological states, or health conditions among Indian adults. Methods: The study had two phases viz., phase1 (n = 18) studied two ONSs: A1 and B1 and phase 2 (n = 20) studied five ONSs: A2, B2, C2, D2 & E2. The subjects were healthy, non-diabetic adults, aged between 20 - 44 years with a mean Body Mass Index of 21.2 ± 1.52 kg/m2 (Phase 1) and 21.0 ± 1.45 kg/m2 (Phase 2). All these ONSs were compared with reference drinks (glucose). The carbohydrates in one serving of each ONS were matched to carbohydrates from 25 grams of glucose following ISO 2010 guidelines. Capillary blood was assessed for blood glucose response at baseline, 15, 30, 45, 60, 90 and 120 minutes. GI was calculated as the incremental area under the curve (iAUC) for the test drinks and expressed as a percentage of the average iAUC from glucose. Results: Phase 1 indicated that the high fiber diabetes-specific nutrition supplement A1 with higher protein (23% energy), higher fat (25% energy) and reduced carbohydrates (40% energy) had a significantly (p = 0.002) lower GI [34 (±6)] as compared to B1 [63 (±7)] (protein 19%, fat 7% and carbohydrates 60% energy) even with similar amount (22%) and type of fiber. Phase 2 reported that all test products [A2 (32 ± 5), B2 (37 ± 4), C2 (31 ± 5), D2 (31 ± 5) and E2 (55 ± 4)] had a low GI. As compared to phase 1, ONSs in phase 2 had lower fiber content (1.6% - 4.6% energy). Conclusion: The glycemic index of oral nutrition supplements is influenced not only by their fiber content, but also by the overall macronutrient composition including protein (≥17% energy), fat (≥10% - 27% energy) and carbohydrates (40% - 57.5% energy).

基于VAE-Kmeans算法的台区聚类精准画像技术

构建起台区用电的精准画像,刻画台区负荷特性及用电模式,对精细化负荷预测、负荷波动分析溯源及台区业务场景能够起到精准指导作用。为此,提出一种基于VAE(变分自编码)-Kmeans算法的台区聚类精准画像技术。采用变分自编码、Kmeans聚类和时间序列相似度算法,从多种维度提取台区和行业负荷的典型曲线,通过综合评估确定最相似的行业负荷,为台区分配相应的画像标签。以占比较大的居民台区为例,构建基于聚类分析和决策树算法的深度挖掘和精准描绘策略,形成了14种城乡居民用电台区精准画像类别,为精细化负荷预测、差异化台区运维管理策略提供了坚实基础。

Pollutant loads of surface runoff in Wuhan City Zoo, an urban tourist area

The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load （e.g. animal yard〉roof〉woodland〉road）, with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M（V） curve indicate that no first flush effect existed in the surface runoff from pervious areas （e.g. woodland, animal ground yard）, whereas a first flush effect was evident in runoff from impervious surfaces （e.g. animal cement yard, roof, road）.

Relationship between the specific surface area of rust and the electrochemical behavior of rusted steel in a wet–dry acid corrosion environment

The relationship between the specific surface area（SSA） of rust and the electrochemical behavior of rusted steel under wet-dry acid corrosion conditions was investigated. The results showed that the corrosion current density first increased and then decreased with increasing SSA of the rust during the corrosion process. The structure of the rust changed from single-layer to double-layer, and the γ-FeOOH content decreased in the inner layer of the rust with increasing corrosion time; by contrast, the γ-FeOOH content in the outer layer was constant. When the SSA of the rust was lower than the critical SSA corresponding to the relative humidity during the drying period, condensed water in the micropores of the rust could evaporate, which prompted the diffusion of O_2 into the rust and the following formation process of γ-FeOOH, leading to an increase of corrosion current density with increasing corrosion time. However, when the SSA of the rust reached or exceeded the critical SSA, condensate water in the micro-pores of the inner layer of the rust could not evaporate which inhibited the diffusion of O_2 and decreased the γ-FeOOH content in the inner rust, leading to a decrease of corrosion current density with increasing corrosion time.

Determination of Carboplatin Dose by Area Under the Curve in Combination Chemotherapy for Senile Non-small Cell Lung Cancer

To preliminarily determine the appropriate dosage of carboplatin （CBP） at AUC of 5 mg-M1^-1·min^-1 in the combination chemotherapy for Chinese senile patients with non-small cell lung cancer （NSCLC）. Thirty-five Chinese senile patients with NSCLC in advanced stage （Ⅲ/Ⅳ） were given 96 cycles of combination chemotherapy. Chemotherapy schedules included Taxol＋CBP, Gemzar＋CBP and NVB＋CBE The dose of CBP was at 5 mg.mL^-1·min^-1 of area under the concentration-time curve （AUC）. Side effects and quality of life were observed before and after the chemotherapy. Myelosuppression was severe and commonly observed. Grade 3/4 of granulocytopenia was found in 47.9% （46/96） of the patients and grade 3/4 of thrombocytopenia was noted in 28.1% （27/96） of the subjects. However, other side effects were slight. The mean score of quality of life （QOL）, according to the criteria of QOL for Chinese cancer patients had reduced 6.8. At 5 mg.mL^-1·min^-1 by AUC, the hematological toxicity of CBP was severe and it had some negative effects on the QOL. The administration of CBP at 5 mg.mL^-1·min^-1 by AUC may be too high for Chinese senile patients with non-small cell lung cancer.

Area under the curve of methotrexate and creatinine clearance are outcome - determining factors in primary CNS lymphomas

Although high-dose methotrexate(HD-MTX)is the most effective drug against primary CNS lymphomas(PCNSL),outcome-de-termining variables related to its administration schedule have not been defined.The impact on toxicity and outcome of the area under thecurve(AUC(MTX)),dose intensity(DI(MTX))and infusion rate(IR(MTX))of MTX and plsamatic creatinine clearance(CL(crea))was investigated in a retrospective series of 45 PCNSL patients treated with three different HD-MTX-basedcombinations.Anticon-vulsants were administered in 31 pts(69%).Age>60 years,anticonvulsant therapy,slow IR(MTX)(

Women with Fear of Childbirth Perceived Large Accumulated Labor Pain in Japan

Background: To improve negative birth experiences among women who experience intense labor pain during labor, it is important to examine the relationship between fear of childbirth immediately after vaginal delivery and the actual intensity of labor pain. However, previous studies have generally evaluated labor pain in a retrospective setting. Purpose: This study examined the relationship between fear of childbirth immediately after vaginal delivery and the actual labor pain intensity and accumulated labor pain intensity without pharmacological pain relief during labor in Japan. Methods: A prospective observational study was conducted between July 2015 and April 2016. Forty-seven pregnant Japanese women were available for analysis. Fear of childbirth was measured by the Japanese version of the Wijma Delivery Expectancy/Experience Questionnaire (JW-DEQ) version B on the third day after vaginal delivery. Participants with scores of 85 or higher were categorized in the high JW-DEQ group, having severe fear of childbirth. Labor pain intensity was examined chronologically in real time with stepwise usage of two types of Numeric Rating Scale (NRS). Accumulated labor pain intensity was calculated using the area under the curve (AUC). Results: Nine participants were in the high JW-DEQ group and eight of the nine were primiparae. Primiparae in the high JW-DEQ group experienced significantly longer duration and larger accumulated labor pain intensity between the onset of labor and 4 to 6 cm of cervical dilatation than those in the low JW-DEQ group (P = 0.024 and P = 0.021, respectively). Conclusions/Implications for Practice: The latent phase of labor was a key stage to improve fear of childbirth immediately after vaginal delivery without pharmacological pain relief among Japanese primiparae. Midwives should give assistance in the latent phase of labor by focusing on progressing labor smoothly and relieving labor pain to improve negative birth experiences.

Analysis of Storm Pattern for Design Urban Drainage System in the Monsoon Areas of Vietnam

In Vietnam,rainfall data usually received using daily rainfall at all hydrology stations with higher time resolution are scarce.However,its analyses to achieve IDF(Intensity-Duration-Frequency)curves are often required at a finer scale such as hourly.Therefore,it needs to develop and apply methods to derive the IDF characteristics of short-duration events from daily rainfall statistics in Vietnam.In recent years,the need for new insights into the rainfall process leading to new approaches to model the distribution of rainfall intensities in time and space was recognized.This research aims to establish IDF curves for monsoon climate area in Vietnam based on scaling method.Scaling properties of extreme rainfall are examined in the Red River Delta of Vietnam in order to establish scaling behavior of statistical moments over different durations.Such scaling or scale-invariant models enable us to scale data from one temporal resolution to another,and thus,help to overcome the lack of the extreme rainfall data of sub-daily durations.The disaggregation or downscaling techniques are used to obtain sub-daily rainfall data from daily rainfall data for the derivation of scaled IDF curves.Research results show that most of rainfall amount(approximately 70%)received from rains occurring between 6:0 pm to 6:0 am of the day after that,the daytime usually less rainfall occurrence with only 30%.The peak rainfall is usually occurred during 0:0 am to 4:0 am having approximately 42.98%of rainfall amount over a day.The peak rainfall likely happen earlier in the recent year(36%rainfall amount over a day occurrence from 6:00 pm to 10:00 pm in 2008).The analysis also illustrated that approximately 40%of rainfall events have duration less than 60 minutes.In contrast,only approximately 9%of rainfall events have duration more than 6 hours but total rainfall depths of these events is approximately.

Pore-throat Structure of Tight Sandstone in Yanchang Formation of Huangling Mining Area Based on Scanning Electron Microscopy and Mercury Porosimmetry

Based on scanning electron microscopy and mercury porosimmetry,a large number of experimental data of pores and pore throats of tight sandstone reservoirs are obtained,and the characteristics of pore types,capillary pressure curves and quantitative parameters of pore throats of Yanchang Formation in Huangling mining area are studied.The results show that the main reservoir space types of Yanchang Formation sandstone are primary intergranular pores and feldspar dissolution pores.The pore-throat structure is medium-small pore and thin-small throat type,and the sorting is good to medium.The mercury porosimmetry curve shows a slightly coarse-thin skew.Combining the morphological characteristics of the mercury porosimmetry capillary pressure curve and the quantitative parameter characteristics of pore throats,the Yanchang Formation s micro pore structure is divided into types I,II,III,and IV.Tight oil reservoirs with type I and II pore structure characteristics are favorable.This study has reference significance for the later evaluation of tight sandstone reservoirs in Huangling mining area.

Influences of Resistor-Type Superconducting Fault Current Limiter on Power System Transient Stability with Asymmetrical Short-Circuit Faults

The transient stability of a single machine to infinite-busbar power system with resistortype superconducting fault current limiters （SFCL） is analyzed under asymmetrical short-circuit fault conditions. The SFCL is considered to introduce a resistance into the three-phase circuits when faults occur. Based on the power-angle curves for different short-circuit conditions of the single-line to ground, double-line to ground and line to line short-circuit faults, the influences of the SFCLs on transient stability are analyzed in detail. The time-domain simulation of transient stability is carried out to verify the analytical results.