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Genomic Epidemiology of Foodborne bla_(NDM-9) Gene-Carrying Extensively Drug-Resistant(XDR)Salmonella enterica Serovar Indiana ST17
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作者 Yujie Hu Peiyuan Huang +7 位作者 Maosong Tian Lei Zheng Jun He Bingbing Li Jianyun Zhao Séamus Fanning Li Bai Yinping Dong 《Biomedical and Environmental Sciences》 2025年第12期1558-1563,共6页
Antimicrobial resistance(AMR)has become a critical global public health challenge in the 21st century.Since the initial isolation of a blaNDM-1-carrying and carbapenem-resistant Klebsiella pneumoniae from an Indian ho... Antimicrobial resistance(AMR)has become a critical global public health challenge in the 21st century.Since the initial isolation of a blaNDM-1-carrying and carbapenem-resistant Klebsiella pneumoniae from an Indian hospital in 2009[1],the escalating prevalence of New Delhi metallo-β-lactamase(NDM)-encoding genes(blaNDM)has transformed carbapenem resistance into a worldwide phenomenon,transcending national and regional boundaries[2].Up to 90 distinct NDM variants have been reported globally according to the NCBI GenBank Pathogens database.Plasmidmediated horizontal gene transfer(HGT),which occurs both within and across bacterial species,has significantly accelerated the global dissemination of blaNDM-related genes and the associated resistance[3].Carbapenem-resistant pathogens were responsible for 200,000 deaths globally in 2019[4].Although NDM-1 has been relatively well characterized[5],the epidemiological profiles of other NDM variants require continued surveillance and indepth investigation.The novel NDM-9 variant(GenBank accession no.KC999080)was first identified in 2013 from a clinically significant isolate of Klebsiella pneumoniae ST107 strain PPH1303 with a high level of resistance to carbapenems recovered from the urine culture of a pediatric patient in Beijing,China,who had acute lymphocytic leukemia and had undergone allogeneic stem cell transplantation[6]. 展开更多
关键词 extensively drug resistant carbapenem resistance genomic epidemiology FOODBORNE blandm Salmonella enterica serovar Indiana ST antimicrobial resistance amr klebsiella pneumoniae
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Vein cuff interposition for short renal vein in living-donor kidney transplantation:Three case reports and review of literature
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作者 Brahim Lekehal Noura Ait Youssef +3 位作者 Mehdi Lekehal Tarik Bakkali Asma Jdar Ayoub Bounssir 《World Journal of Transplantation》 2026年第1期239-248,共10页
BACKGROUND With the increasing use of laparoscopic techniques in living-donor kidney transplantation,limitations in donor vessel length,particularly of the right renal vein,pose significant challenges for vascular ana... BACKGROUND With the increasing use of laparoscopic techniques in living-donor kidney transplantation,limitations in donor vessel length,particularly of the right renal vein,pose significant challenges for vascular anastomosis to the recipient’s external iliac vein.These anatomical constraints can complicate graft implantation and increase the risk of postoperative complications.CASE SUMMARY To address the issue of short right renal veins,several surgical strategies have been proposed.In this report,we describe our experience with three cases in which venous extension was successfully achieved using a venous cuff interposition technique during back-table reconstruction.This approach was used to facilitate secure vascular anastomosis and improve graft positioning in anatomically complex transplant scenarios.CONCLUSION Venous cuff interposition represents an effective technique for managing short renal veins in living-donor kidney transplantation.It provides additional length and flexibility,easing anastomotic tension and supporting successful transplantation. 展开更多
关键词 Vein cuff interposition Living donor kidney Laparoscopic donor nephrectomy Renal vein extension Gonadal vein Great saphenous vein Case report
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Extensively drug-resistant bacteria are an independent predictive factor of mortality in 130 patients with spontaneous bacterial peritonitis or spontaneous bacteremia 被引量:19
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作者 Alexandra Alexopoulou Larisa Vasilieva +5 位作者 Danai Agiasotelli Kyriaki Siranidi Sophia Pouriki Athanasia Tsiriga Marina Toutouza Spyridon P Dourakis 《World Journal of Gastroenterology》 SCIE CAS 2016年第15期4049-4056,共8页
AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.METHODS: We prospectively collected clinical, labor... AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid &#x0003e; 250/mm<sup>3</sup>. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed.RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included XDR infection (HR = 2.263, 95%CI: 1.005-5.095, P = 0.049), creatinine (HR = 1.125, 95%CI: 1.024-1.236, P = 0.015) and INR (HR =1.553, 95%CI: 1.106-2.180, P = 0.011).CONCLUSION: XDR bacteria are an independent life-threatening factor in SBP/SB. Strategies aiming at restricting antibiotic overuse and rapid identification of the responsible bacteria could help improve survival. 展开更多
关键词 Spontaneous bacterial peritonitis Spontaneous bacteremia Multidrug-resistant bacteria extensively drug-resistant bacteria Susceptibility to antibiotics
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基于延拓补偿策略的气体传感器端点效应诊断
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作者 朱健松 邢博轩 +2 位作者 孟凡利 王浩 唐坤 《沈阳理工大学学报》 2026年第1期36-43,共8页
针对经验模态分解(empirical mode decomposition,EMD)处理非平稳信号时因端点效应造成分解结果失真的问题,提出一种基于麻雀搜索算法(sparrow search algorithm,SSA)与长短时记忆(long short-term memory,LSTM)网络的耦合模型,突破传... 针对经验模态分解(empirical mode decomposition,EMD)处理非平稳信号时因端点效应造成分解结果失真的问题,提出一种基于麻雀搜索算法(sparrow search algorithm,SSA)与长短时记忆(long short-term memory,LSTM)网络的耦合模型,突破传统梯度下降算法易陷入局部最优的局限,显著提升时序预测精度。首先将气体响应信号预处理为周期特征变量;然后采用双向周期延拓策略,通过LSTM-SSA深度训练,生成首尾各延伸一个周期的预测序列;最后利用双向性预测序列构建复合信号,并对其进行EMD分解。以丙酮和甲苯信号为例的实验结果表明,经LSTM-SSA预测后再进行EMD分解时端点效应引起的能量误差分别降低了74.966%和23.368%、正交性系数分别提升了51.444%和34.990%,有效抑制了端点处模态分量的幅值失真,提升了EMD的可靠性,为气体传感信号的特征提取与工业安全监测提供了新思路。 展开更多
关键词 经验模态分解 端点效应 麻雀搜索算法 长短时记忆网络 周期延拓
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Prolonged use of bedaquiline in two patients with pulmonary extensively drug-resistant tuberculosis: Two case reports 被引量:4
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作者 Jing-Tao Gao Li Xie +6 位作者 Li-Ping Ma Wei Shu Li-Jie Zhang Yu-Jia Ning Shi-Heng Xie Yu-Hong Liu Meng-Qiu Gao 《World Journal of Clinical Cases》 SCIE 2021年第10期2326-2333,共8页
BACKGROUND Bedaquiline is among the prioritized drugs recommended by the World Health Organization for the treatment of extensively drug-resistant tuberculosis(XDRTB).Many patients have not achieved better clinical im... BACKGROUND Bedaquiline is among the prioritized drugs recommended by the World Health Organization for the treatment of extensively drug-resistant tuberculosis(XDRTB).Many patients have not achieved better clinical improvement after bedaquiline is stopped at 24 wk.However,there is no recommendation or guideline on bedaquiline administration beyond 24 wk,which is an important consideration when balancing the benefit of prognosis for XDR-TB against the uncertain safety concerning the newer antibiotics.CASE SUMMARY This paper reported 2 patients with XDR-TB(a female of 58 years of age and a female of 18 years of age)who received bedaquiline for 36 wk,as local experience to be shared.The 2 cases had negative cultures after 24 wk of treatment,but lung imaging was still positive.After discussion among experts,the consensus was made to bedaquiline prolongation by another 12 wk.The 36-wk prolonged use of bedaquiline in both cases achieved a favorable response without increasing the risk of cardiac events or new safety signals.CONCLUSION Longer regimen,including 36-wk bedaquiline treatment,might be an option for patients with XDR-TB.More studies are needed to explore the effectiveness and safety of prolonged use of bedaquiline for 36 wk vs standard 24 wk in the treatment of multidrug-resistant/XDR-TB or to investigate further the biomarkers and criteria indicative for extension of bedaquline to facilitate clinical use of thisnovel drug. 展开更多
关键词 Pulmonary tuberculosis Bedaquiline extensively drug-resistant tuberculosis TUBERCULOSIS Case report
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Successful treatment of pyogenic ventriculitis caused by extensively drug-resistant Acinetobacter baumannii with multi-route tigecycline: A case report 被引量:3
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作者 Wei Li Dan-Dong Li +3 位作者 Bo Yin Dong-Dong Lin Han-Song Sheng Nu Zhang 《World Journal of Clinical Cases》 SCIE 2021年第3期651-658,共8页
BACKGROUND Pyogenic ventriculitis caused by extensively drug-resistant Acinetobacter baumannii(A.baumannii)is one of the most severe complications associated with craniotomy.However,limited therapeutic options exist f... BACKGROUND Pyogenic ventriculitis caused by extensively drug-resistant Acinetobacter baumannii(A.baumannii)is one of the most severe complications associated with craniotomy.However,limited therapeutic options exist for the treatment of A.baumannii ventriculitis due to the poor penetration rate of most antibiotics through the blood-brain barrier.CASE SUMMARY A 68-year-old male patient with severe traumatic brain injury developed pyogenic ventriculitis on postoperative day 24 caused by extensively drug-resistant A.baumannii susceptible to tigecycline only.Successful treatment was accomplished through multi-route administration of tigecycline,including intravenous combined with continuous ventricular irrigation plus intraventricular administration.The pus was cleared on the 3rd day post-irrigation,and cerebrospinal fluid cultures were negative after 12 d.CONCLUSION Our findings suggest that multi-route administration of tigecycline can be a therapeutic option against pyogenic ventriculitis caused by extensively drugresistant A.baumannii. 展开更多
关键词 Pyogenic ventriculitis Acinetobacter baumannii extensively drug-resistant TIGECYCLINE Ventricular irrigation Case report
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含裂纹故障的双齿圈人字行星齿轮传动系统动力学仿真与均载分析
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作者 任菲 臧旭 +7 位作者 王才东 张德海 崔光珍 王良文 巩晓赟 李立伟 杨贺 杜燕来 《河南理工大学学报(自然科学版)》 北大核心 2026年第1期128-135,共8页
目的 研究不同类型裂纹故障对双齿圈人字行星齿轮传动系统接触力特性和均载性能的影响规律。方法 基于SolidWorks和ADAMS进行故障联合仿真研究,分别建立健康状态和行星轮上具有贯穿型、非贯穿型和端面贯穿型3种不同裂纹故障的双齿圈人... 目的 研究不同类型裂纹故障对双齿圈人字行星齿轮传动系统接触力特性和均载性能的影响规律。方法 基于SolidWorks和ADAMS进行故障联合仿真研究,分别建立健康状态和行星轮上具有贯穿型、非贯穿型和端面贯穿型3种不同裂纹故障的双齿圈人字行星齿轮传动系统精确虚拟样机模型,采用GSTIFF积分法求解健康和不同典型裂纹故障状态下的轮齿接触力,计算系统均载系数,分析内、外啮合副在时频域上的接触力特性和系统均载特性的变化规律。结果 结果表明,健康状态下各齿轮副的接触力呈稳定的周期性变化,仿真基频与啮合频率数值相差仅1%;系统内、外啮合副均载系数为1.006和1.007,啮合传动表现出良好的均载性能。存在裂纹故障时,贯穿型裂纹深度扩展到30 mm时,内、外啮合副均载系数增大6.2%和9.2%;贯穿型裂纹角度扩展到60°时,内、外啮合副均载系数增大6.6%和7.8%;非贯穿型裂纹有效长度扩展到120 mm时,内、外啮合副均载系数增大4.3%和4.1%;端面贯穿型裂纹有效宽度扩展到150 mm时,内、外啮合副均载系数增大10.8%和11.4%。结论 随着裂纹故障程度加深,均载系数逐渐增大,即均载性能逐渐变差。系统外啮合均载性能受到的影响比内啮合更大,行星轮存在端面贯穿型裂纹故障对系统的均载性能影响显著大于贯穿型和非贯穿型裂纹。 展开更多
关键词 双齿圈人字行星齿轮 裂纹故障 虚拟样机 裂纹扩展类型 接触力 均载特性
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Global burden of HIV-negative multidrug-and extensively drug-resistant tuberculosis based on Global Burden of Disease Study 2021 被引量:4
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作者 Yiming Chen Weiye Chen +7 位作者 Zile Cheng Yiwen Chen Min Li Lingchao Ma Nan Zhou Jing Qian Yongzhang Zhu Chang Liu 《Science in One Health》 2024年第1期171-180,共10页
Background:Tuberculosis(TB),caused by Mycobacterium tuberculosis,remains the second leading cause of death from a single infectious disease globally and poses a significant economic and clinical burden in the world in... Background:Tuberculosis(TB),caused by Mycobacterium tuberculosis,remains the second leading cause of death from a single infectious disease globally and poses a significant economic and clinical burden in the world in 2022.Of particular concern is the emergence of drug-resistant TB,accounting for 15%-20%of TB deaths.It is imperative to delve into the global trends of incidence and death rate for multidrug-resistant tuberculosis(MDRTB)and extensively drug-resistant tuberculosis(XDR-TB),drawing upon the comprehensive Global Burden of Disease(GBD)2021 drug-resistant tuberculosis dataset.Methods:From the GBD 2021,data on incidence,prevalence,disability-adjusted life years(DALYs),and death of MDR-TB and XDR-TB from 1990 to 2021 were collected.We calculated the estimated annual percentage changes in age standardized incidence rate(ASIR)and age-standardized death rate(ASDR),segmented by age,sex,and socio-demographic index(SDI).The impacts of various risk factors on MDR-TB and XDR-TB were also analyzed.Results:In 2021,there were an estimated 443,680(95%uncertainty interval[UI]:259,196-766,545)incident cases of MDR-TB,and an estimated 106,818(95%UI:41,612-211,854)death cases of MDR-TB,while there were an estimated 24,036(95%UI:17,144-34,587)incident cases of XDR-TB and 7,946(95%UI:3,326-14,859)death cases of XDR-TB.The incidence and death cases of MDR-TB were lowest in high SDI regions,whereas the incidence rates of XDR-TB in high-middle SDI regions were higher than those in middle SDI and high SDI regions.Conclusion:This study reported the disease burden of drug-resistant TB from 1990 to 2021.Until 2021,drugresistant TB is still a serious problem in low SDI countries,especially for high-risk age populations with highrisk factors.Controlling drug-resistant TB requires effective control strategies and healthcare systems. 展开更多
关键词 Multidrug-resistant tuberculosis extensively drug-resistant tuberculosis Global burden of disease Incidence rate Death rate
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Extensively drug-resistant Salmonella typhi causing rib osteomyelitis: A case report
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作者 Sara Iqbal Humza Thobani Saulat Fatimi 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2021年第5期231-233,共3页
Rationale:Salmonella(S.)typhi is a rare cause of osteomyelitis in immunocompetent adults.Extensive drug resistance(XDR)may lead to more complicated cases of S.typhi osteomyelitis.Patient concern:A 55-year-old female p... Rationale:Salmonella(S.)typhi is a rare cause of osteomyelitis in immunocompetent adults.Extensive drug resistance(XDR)may lead to more complicated cases of S.typhi osteomyelitis.Patient concern:A 55-year-old female presented with a persistent low-grade fever and a swelling on her lower left chest with a sinus discharging purulent fluid for the past 8 months.Her symptoms had been unresponsive to previous anti-microbial therapy.Diagnosis:Rib osteomyelitis caused by XDR S.typhi.Interventions:Surgical wound debridement,left 7th-9th rib resection and intravenous Ⅳ meropenem were done.Outcome:Fever resolved and left-sided swelling resected without recurrence.Lessons:The prevalence of XDR S.typhi is growing in South Asia and should be considered as the differential diagnosis of chronic osteomyelitis. 展开更多
关键词 Salmonella typhi Extensive drug resistance RIB OSTEOMYELITIS IMMUNOCOMPETENCE
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Establishment of extensively drug-resistant Pseudomonas aeruginosa pneumonia model in rat
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作者 AN Ran LIU Feng-yun +8 位作者 ZHAO Qi-liang CAI Wen-xin SUN Hong-yuan CHEN Ming-hu CHANG Li YIN Yan-zhong LIU Kai ZHANG Hui-qi LIU Min 《Journal of Hainan Medical University》 CAS 2023年第15期7-13,共7页
Objective:To establish extensively drug-resistant Pseudomonas aeruginosa(XDR-PA)infection-induced pneumonia model in rats.Methods:Twenty-four male SD rats were randomly divided into blank group,low bacterial group,med... Objective:To establish extensively drug-resistant Pseudomonas aeruginosa(XDR-PA)infection-induced pneumonia model in rats.Methods:Twenty-four male SD rats were randomly divided into blank group,low bacterial group,medium bacterial group,and high bacterial group.The low,medium and high bacterial groups were given intratracheal instillation of 0.1 mL of bacterial suspension(bacterial concentration in turn is 7.5×10^(9),3×10^(10),6×10^(10)CFU/mL),while the blank group were given the same volume of sterile normal saline.After modeling,the general conditions of rats in each group were observed,including mental state,hair,respiration,activity,eating,weight,and the survival curve was drawn.The pathological characteristics of lung tissue and the infiltration of inflammatory cells were observed.Pathogenic identification of each group was carried out by bacterial culture of lung tissue homogenate.Results:The general state of the blank group was normal,and the rats in other groups showed signs of mental depression,bristling,shortness of breath,even oral and nasal bleeding,decreased food intake and activity,and significant weight loss,and different degrees of death within 48 hours,the difference was statistically significant(P<0.05).Pathological results showed that the alveolar structure of rats in the blank group was complete,and the alveolar space was clear without exudation.The lung tissue of the low and medium bacterial groups showed obvious inflammatory cell infiltration,alveolar structure destruction,alveolar septum thickening,interstitial edema,but the pathological damage of the medium group was more severe,with a mortality rate of up to 50%,and the mortality rate of the low bacterial group was 17%.In the high bacterial group,red blood cells,inflammatory cells and a large amount of fibrin-like exudation can be seen in the alveolar space,which has the pathological characteristics of acute respiratory failure,and the mortality rate is as high as 67%.The results of bacterial culture of lung tissue homogenate showed that the blank group had no bacterial colonies,while PA colony growth can be seen in low,medium and high bacterial groups.Conclusion:9 Intratracheal instillation of low bacterial count(0.1 mL of 7.5×10^(9) CFU/mL)XDR-PA bacterial suspension can successfully construct a rat pneumonia model of XDR-PA infection. 展开更多
关键词 extensively drug-resistant Pseudomonas aeruginosa PNEUMONIA Animal model RAT
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An Extensively Drug Resistant Acinetobacter baumannii from Soft Tissue Isolated in a Hospital in Senegal
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作者 Cheikh Fall Ousmane Sow +3 位作者 Fatim P. Ly Boly Diop Bissoume Sambe-Ba Yakhya Dieye 《Case Reports in Clinical Medicine》 2022年第3期72-78,共7页
Emerging and rapidly spreading multidrug resistant bacteria constitute a rising public health concern worldwide. Acinetobacter baumannii is one of these bacteria that cause different infections including pneumonia, ba... Emerging and rapidly spreading multidrug resistant bacteria constitute a rising public health concern worldwide. Acinetobacter baumannii is one of these bacteria that cause different infections including pneumonia, bacteremia, meningitis, soft-tissue, and urinary tract infections, and are associated with high mortality and economic burden. We present a case of a 43-year-old woman, admitted at the department of orthopedics, regional hospital of Ourossogui, North-East of Senegal for soft-tissue injuries. Initially diagnosed with Yersinia pestis infection, the patient was well managed before being released. Supplementary sampling for confirmatory tests allowed the detection of an extensively drug-resistant Acinetobacter baumannii clone. 展开更多
关键词 Acinetobacter baumannii extensively Drug Resistance SOFT-TISSUE Senegal
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改进邻域扩展A^(*)算法的移动机器人路径规划 被引量:4
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作者 董雅文 杨静雯 +1 位作者 张宝锋 赵小惠 《机械设计与制造》 北大核心 2025年第1期291-295,共5页
为解决A^(*)算法在规划路径时存在转折角度过大、路径不平滑的问题,提出改进邻域扩展A^(*)算法。首先,对A^(*)算法搜索范围扩展至24邻域,然后对邻域进行二次数量优化处理得到最终邻域搜索节点。其次,设计具有双层位置导向信息的评价函数... 为解决A^(*)算法在规划路径时存在转折角度过大、路径不平滑的问题,提出改进邻域扩展A^(*)算法。首先,对A^(*)算法搜索范围扩展至24邻域,然后对邻域进行二次数量优化处理得到最终邻域搜索节点。其次,设计具有双层位置导向信息的评价函数,最后对所得路径进行二次平滑处理以剔除冗余节点并削弱路径尖峰的剧烈程度。仿真结果表明,改进邻域扩展A^(*)算法在路径长度、搜索节点数量、规划时间上均优于传统A^(*)算法,且路径无尖峰转角,整体趋势平缓。 展开更多
关键词 点对点路径规划 A^(*)算法 邻域扩展
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考虑应力比的TRIP双相钢疲劳裂纹扩展试验及有限元模拟 被引量:3
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作者 邹宗园 宋宇 +1 位作者 池艳阳 陈雷 《钢铁》 北大核心 2025年第4期114-124,共11页
疲劳裂纹扩展行为是引起工程结构件失效的最重要原因之一,而应力比是影响疲劳裂纹扩展行为的重要因素。因此,分析应力比对工程结构件的直接影响十分必要。针对以Mn-N代替Ni元素的高性能TRIP(transformation induced plasticity)双相不锈... 疲劳裂纹扩展行为是引起工程结构件失效的最重要原因之一,而应力比是影响疲劳裂纹扩展行为的重要因素。因此,分析应力比对工程结构件的直接影响十分必要。针对以Mn-N代替Ni元素的高性能TRIP(transformation induced plasticity)双相不锈钢,利用INSTRON 8801液压伺服疲劳试验机,开展应力比分别为0.1、0.2、0.3和0.5的疲劳裂纹扩展试验研究。测得不同应力比下的疲劳裂纹扩展门槛值,分析应力比对疲劳裂纹扩展门槛值的影响规律,并建立了疲劳裂纹扩展门槛值预测模型;基于Pairs模型、Elber模型以及改进的Forman模型,分别对不同应力比下的疲劳裂纹扩展速率与应力强度因子关系进行理论建模,求解模型参数,并比较分析3种模型的预测精度、特点以及适用性,探讨应力比对TRIP双相钢疲劳裂纹扩展速率的影响。基于扩展有限元法,对不同应力比的疲劳裂纹扩展行为开展有限元模拟,模拟结果与试验结果吻合良好。模拟结果准确揭示了TRIP双相钢在不同应力比下疲劳裂纹扩展过程中的等效应力分布、塑性变形区及裂纹形状的变化规律。研究结果不仅可以丰富该类高性能TRIP双相钢疲劳裂纹扩展行为的基础试验数据,而且可以揭示应力比对该类试验钢疲劳裂纹扩展行为的影响规律,对进一步开发并应用此类高性能TRIP双相钢具有非常重要的意义。 展开更多
关键词 TRIP双相钢 CT试样 应力比 疲劳裂纹扩展行为 疲劳裂纹扩展试验 疲劳裂纹扩展门槛值 预测模型 扩展有限元法
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承包地“二轮延包”:关于政策指南的思考 被引量:7
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作者 罗必良 米运生 《农业经济问题》 北大核心 2025年第1期16-26,共11页
为规范和指导即将在全国范围内全面展开的承包地“二轮延包”工作,有必要出台相应的政策指南。“二轮延包”工作的政策指南既要强调承包关系的长久不变,以延续保障农户土地权利的既有政策;也要根据人地关系的新特征和农业高质量发展面... 为规范和指导即将在全国范围内全面展开的承包地“二轮延包”工作,有必要出台相应的政策指南。“二轮延包”工作的政策指南既要强调承包关系的长久不变,以延续保障农户土地权利的既有政策;也要根据人地关系的新特征和农业高质量发展面临的新问题,指引农地制度的改革之路。基于农业新旧动能转换的现实,针对“四个松弛”人地关系的新特征,为放活土地经营权、提高农地的配置与利用效率,“二轮延包”政策的核心基调宜为:以自动顺延承包期限为主;严格程序和限定条件的小调整;保持农地流转关系的稳定;促进农地流转市场的高质量发展;完善农地“三权分置”的制度框架。 展开更多
关键词 承包地 “二轮延包” 政策架构
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我国冰雪运动“南展西扩东进”战略推进研究 被引量:6
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作者 於鹏 王健 +1 位作者 陈刚 倪志伟 《体育文化导刊》 北大核心 2025年第1期24-31,共8页
运用文献资料、专家访谈、实地考察等方法,探究后冬奥时期我国冰雪运动“南展西扩东进”战略推进的内在逻辑、困境,并提出路径。内在逻辑:以国家体育发展需要为根本遵循,以加快推动体育强国建设为价值目标,以“点—面—全”循序渐进为... 运用文献资料、专家访谈、实地考察等方法,探究后冬奥时期我国冰雪运动“南展西扩东进”战略推进的内在逻辑、困境,并提出路径。内在逻辑:以国家体育发展需要为根本遵循,以加快推动体育强国建设为价值目标,以“点—面—全”循序渐进为战略布局。困境:冰雪文化底蕴薄弱,常态化参与者数量不足;冰雪运动资源短缺,服务供给质量不高;冰雪产业不健全,现代化水平较低;冰雪整体竞技实力薄弱,后备人才培养体系待完善。路径:加强冰雪文化传播,营造冰雪文化氛围;统筹推进资源建设,提供高质量冰雪服务;打造冰雪全产业链,推动冰雪产业升级;提升冰雪整体竞技实力,完善后备人才培养体系。 展开更多
关键词 体育管理 冰雪运动 “南展西扩东进”战略
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高校实验室安全韧性评价及障碍因子诊断 被引量:3
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作者 瞿英 李晨旭 +1 位作者 张斌 杨梅 《实验技术与管理》 北大核心 2025年第3期219-225,共7页
为有效反映高校实验室安全韧性的动态演进特征,规避因偏差评价导致的风险误判问题,该文基于韧性动态演进的抗逆力、恢复力和适应力过程属性,构建安全韧性评价指标体系,采用改进物元模型测度韧性水平,结合贴近度理论和等级特征指数获取... 为有效反映高校实验室安全韧性的动态演进特征,规避因偏差评价导致的风险误判问题,该文基于韧性动态演进的抗逆力、恢复力和适应力过程属性,构建安全韧性评价指标体系,采用改进物元模型测度韧性水平,结合贴近度理论和等级特征指数获取韧性动态演进趋势,并进行障碍因子诊断,客观测度韧性演进水平。该文以某高校实验室为实例对模型进行验证,并将改进模型与传统物元、元模型和优劣解距离法进行对比,验证了改进模型的有效性。结果表明该实验室整体安全韧性等级为Ⅲ级“一般韧性”,但有偏向于Ⅱ级“较弱韧性”的演进趋势,与现实情况吻合。该模型可以直观反映韧性动态演进趋势,为高校实验室制定安全韧性演化控制措施提供参考。 展开更多
关键词 韧性演进 改进物元模型 贴近度 障碍因子
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有限性与延展性:新中国国家安全思想的演进 被引量:1
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作者 祁昊天 赵书韫 《国际安全研究》 北大核心 2025年第1期73-95,157,共24页
文章从国家安全本体论、安全体系认识论与安全实践方法论三个维度考察新中国的国家安全思想,以社会主义革命和建设时期、改革开放和社会主义现代化建设新时期以及中国特色社会主义新时代进行时间分段,讨论新中国国家安全思想的演进。有... 文章从国家安全本体论、安全体系认识论与安全实践方法论三个维度考察新中国的国家安全思想,以社会主义革命和建设时期、改革开放和社会主义现代化建设新时期以及中国特色社会主义新时代进行时间分段,讨论新中国国家安全思想的演进。有限性与延展性是这一演进过程中安全思想的连贯体现,分别涵盖了安全目标、认知与方法在各阶段静态与动态、横向与纵向的特征。虽然新中国在不同时期面临不同的安全环境和安全需求,安全形势愈加复杂,但是安全思想和实践总体符合安全有限、延展演进的特征。安全具有弹性但不可过载,不存在绝对安全的空间,而狭义的、单一领域或维度的安全亦无法有效支撑对国家安全的维护,特别是在愈加复杂和不确定的国家安全环境中更是如此。新中国国家安全思想“有限—延展”的演进特征反映了安全环境的客观变化与领导人主观能动的决策部署。 展开更多
关键词 国家安全思想 演进 有限性 延展性
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基于波动信息优选及切换输入机制的短期延长期风电集群功率预测 被引量:1
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作者 杨茂 鞠超毅 +1 位作者 张薇 苏欣 《太阳能学报》 北大核心 2025年第3期546-558,共13页
在风电功率预测领域,现有短期时间尺度研究和应用的预见期最长为7d,缺乏对8~15d短期延长期时间尺度下的预测研究。针对上述问题,提出基于天气过程挖掘和切换机制的8~15d短期延长期预测框架,着重对未来出力水平进行预测,将历史选择分为... 在风电功率预测领域,现有短期时间尺度研究和应用的预见期最长为7d,缺乏对8~15d短期延长期时间尺度下的预测研究。针对上述问题,提出基于天气过程挖掘和切换机制的8~15d短期延长期预测框架,着重对未来出力水平进行预测,将历史选择分为波动性优先历史选择和稳定性优先历史选择,在波动性优先历史选择效果较差时,利用稳定性优先历史选择进行误差平衡。所提框架在甘肃省某风电集群进行验证,结果表明,所提框架均方根误差在8~15d所有时间尺度下平均降低0.84%~1.45%,在未来数值天气预报(NWP)可用性匮乏的情况下实现了8~15d预测,有效提高短期延长期预测的可靠性。 展开更多
关键词 风电功率 预测 切换机制 优选 短期 短期延长期
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高构造应力区顶板深孔爆破裂纹扩展机制与应用研究 被引量:3
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作者 曹安业 郝琪 +6 位作者 崔玉江 黄书翔 彭雨杰 高振 高红兵 李东 高峰 《采矿与安全工程学报》 北大核心 2025年第1期97-107,共11页
彬长矿区受高构造应力环境和上覆坚硬岩层影响,冲击风险显著,深孔预裂爆破是降低该区域冲击地压风险的有效手段。在高构造应力区开展深孔预裂爆破,其裂纹扩展形式尚不完全清楚。因此,采用LS-DYNA数值软件模拟分析了高构造应力环境、倾... 彬长矿区受高构造应力环境和上覆坚硬岩层影响,冲击风险显著,深孔预裂爆破是降低该区域冲击地压风险的有效手段。在高构造应力区开展深孔预裂爆破,其裂纹扩展形式尚不完全清楚。因此,采用LS-DYNA数值软件模拟分析了高构造应力环境、倾向与走向爆破孔倾角对爆破裂纹扩展的影响,基于模拟结果优化了现场爆破设计。结果表明:在最大水平主应力为主导的高构造应力条件下,裂纹扩展优势面总是沿着垂直于最小水平主应力方向的平面。水平应力差对爆破裂纹的扩展起到主导作用。增大水平应力差,爆破裂纹扩展的程度越高,且越利于爆破裂纹沿着炮孔所在平面扩展。不同的倾向爆破倾角下爆破裂纹扩展的差异性显著,而不同走向爆破倾角下裂纹扩展基本无变化。倾向爆破孔倾角大于75°时,爆破裂纹扩展程度高且裂纹扩展优势面沿着炮孔倾角所在平面。优化了现场爆破设计,现场试验后工作面大能量微震发生的次数与层位显著降低,波速异常系数峰值明显降低,爆破优化有效。 展开更多
关键词 冲击地压 高构造应力 深孔预裂爆破 炮孔倾角 裂纹扩展
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干湿-冻融作用输水渠道膨胀土强度特性及损伤演化规律研究 被引量:2
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作者 姜海波 卢燕 +1 位作者 李琳 张军 《岩土力学》 北大核心 2025年第5期1356-1367,共12页
季节冻土区膨胀土的“干缩湿胀”与“冻胀融沉”效应,诱发了诸多工程病害问题。针对北疆供水工程膨胀土输水渠道强度衰减及边坡失稳破坏问题,以渠基膨胀土所经历的干湿及冻融循环作用为试验边界条件,开展渠基膨胀土不同埋深含水率监测试... 季节冻土区膨胀土的“干缩湿胀”与“冻胀融沉”效应,诱发了诸多工程病害问题。针对北疆供水工程膨胀土输水渠道强度衰减及边坡失稳破坏问题,以渠基膨胀土所经历的干湿及冻融循环作用为试验边界条件,开展渠基膨胀土不同埋深含水率监测试验,分析干湿、冻融不同阶段土体含水率随埋深的变化规律。同时通过干湿-冻融循环室内试验,研究干湿-冻融循环作用对膨胀土不均匀变形、强度衰减及微观结构损伤演化的影响。研究结果表明:(1)干湿-冻融环境下,渠基一定深度范围膨胀土的水分变化剧烈,其中冻融阶段含水率的变化最大,形成了膨胀土的“相变动力区”。(2)干湿-冻融循环作用下,膨胀土微观结构的损伤效应较显著,裂隙随循环次数增加不断发育扩展,膨胀土持续经历着“干缩湿胀”和“冻胀融沉”作用。在干湿-冻融作用的初期,膨胀变形量在总体变形量中贡献较大。经历一定次数的干湿-冻融循环作用后,土体的体积变形、膨胀变形量逐渐趋于稳定。(3)膨胀土的抗剪强度及其强度指标均出现了不同程度的衰减。其中黏聚力的衰减幅度较大,呈指数形式骤减,而内摩擦角的降低幅度则较小。在干湿-冻融作用的初期,黏聚力的衰减幅度占总衰减率的41.2%~48.6%。土体黏聚力的骤减,导致了渠基边坡膨胀土的浅层滑坡破坏,表明黏聚力在边坡失稳中起决定作用。 展开更多
关键词 膨胀土输水渠道 干湿-冻融循环 含水率 强度衰减 裂隙扩展
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