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焊接方法对铝合金焊接接头微弧氧化色差的影响
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作者 刘瑞琳 张梦莹 +3 位作者 门正兴 雷正 杨峰 朱宗涛 《精密成形工程》 北大核心 2024年第5期132-139,共8页
目的分析铝合金焊接接头微弧氧化过程中色差产生的原因。方法采用单激光和激光-MIG复合焊2种焊接方法焊接2A12铝合金,利用RGB值定性描述不同焊接试样的色差差异大小,采用金相、SEM和微区XRD观察2A12铝合金单激光和激光-MIG复合焊接头微... 目的分析铝合金焊接接头微弧氧化过程中色差产生的原因。方法采用单激光和激光-MIG复合焊2种焊接方法焊接2A12铝合金,利用RGB值定性描述不同焊接试样的色差差异大小,采用金相、SEM和微区XRD观察2A12铝合金单激光和激光-MIG复合焊接头微弧氧化前后的组织、微观形貌和表面物相组成。结果经微弧氧化处理后,2A12铝合单激光焊焊件的焊缝和母材之间无明显色差,2A12铝合金激光-MIG复合焊焊件的焊缝和母材之间存在明显色差,结合金相组织、表面和截面的SEM形貌以及表面EDS和XRD测试分析结果可知,成分和表面熔融物颗粒的大小不同是铝合金焊接接头微弧氧化色差形成的主要原因,焊接接头的组织对铝合金焊接接头微弧氧化色差的产生没有影响。结论单激光焊接接头微弧氧化后的氧化色差较激光-MIG复合焊接头的小;铝合金(2A12)焊接接头产生氧化色差主要是因为焊接接头的成分和表面熔融物颗粒大小不同,而组织对色差无影响。 展开更多
关键词 铝合金 单激光 激光-MIG 微弧氧化 色差
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深水井套管强度衰减规律及预防措施研究 被引量:1
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作者 袁征 吴小龙 +4 位作者 雷正 杨浩 唐浩瑞 张智 邓皓匀 《中国安全生产科学技术》 CAS CSCD 北大核心 2024年第2期69-74,共6页
为研究深水井套管柱在多因素耦合作用下管柱完整性失效规律,综合考虑腐蚀、磨损以及温度共同作用,建立套管强度衰减评价方法,对比不同管材在多因素作用下强度衰减程度,提出降低套管强度衰减速率措施。研究结果表明:在腐蚀作用下,随着生... 为研究深水井套管柱在多因素耦合作用下管柱完整性失效规律,综合考虑腐蚀、磨损以及温度共同作用,建立套管强度衰减评价方法,对比不同管材在多因素作用下强度衰减程度,提出降低套管强度衰减速率措施。研究结果表明:在腐蚀作用下,随着生产年限增加,套管强度衰减速率加快。腐蚀速率为1.0 mm/a时,P110套管抗内压强度平均每年下降7.21%;套管强度随磨损深度增加而减小。当磨损深度为0.3 mm时,L80、13Cr-P110和Q1253种管材的抗外挤强度平均下降百分比为6.47%;管材强度一般随着温度升高而降低,当温度为100℃时,P110套管的抗内压强度下降6.37%;选用耐腐蚀、磨损和高温管材能够有效减小强度衰减速率。研究结果可为深水井开发提供参考。 展开更多
关键词 深水套管 强度衰减 多因素 强度校核 预防措施
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并联导弹挂架结构减重优化设计
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作者 张鹏程 雷征 +3 位作者 赵冠臣 李青松 韩召辉 王延生 《机械科学与技术》 CSCD 北大核心 2024年第8期1454-1461,共8页
为实现某新型并联导弹挂架的减重需求,以并联挂架的转接梁为典型对象,利用有限元进行了转接梁的强度分析,确定了最大应力位置和应力分布。通过等效静态载荷法和子模型技术相结合的方式,进行了转接梁子模型的多工况拓扑优化,获取了材料... 为实现某新型并联导弹挂架的减重需求,以并联挂架的转接梁为典型对象,利用有限元进行了转接梁的强度分析,确定了最大应力位置和应力分布。通过等效静态载荷法和子模型技术相结合的方式,进行了转接梁子模型的多工况拓扑优化,获取了材料最佳分布。对几何重建模型进行了尺寸优化,在同时考虑质量、变形和应力的基础上,实现了转接梁结构的详细设计。结果表明,优化后的结构在满足强度条件下,重量减少了43.1%,最大应力下降了13.1%,可为同类产品的减重设计提供参考。 展开更多
关键词 并联导弹挂架 强度分析 等效静载荷法 子模型技术 减重优化设计
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“Baihui”(DU20)-penetrating “Qubin”(GB7) acupuncture on blood–brain barrier integrity in rat intracerebral hemorrhage models via the RhoA/ROCK Ⅱ/MLC 2 signaling pathway
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作者 Ce Zhang Jia zheng +10 位作者 Xueping Yu Binglin Kuang Xiaohong Dai lei zheng Weiwei Yu Wei Teng Hongtao Cao Mingyue Li Jiayong Yao Xiaoying Liu Wei Zou 《Animal Models and Experimental Medicine》 CAS CSCD 2024年第5期740-757,共18页
Background: Blocking the Rho A/ROCK Ⅱ/MLC 2(Ras homolog gene family member A/Rho kinase Ⅱ/myosin light chain 2) signaling pathway can initiate neuroprotective mechanisms against neurological diseases such as stroke,... Background: Blocking the Rho A/ROCK Ⅱ/MLC 2(Ras homolog gene family member A/Rho kinase Ⅱ/myosin light chain 2) signaling pathway can initiate neuroprotective mechanisms against neurological diseases such as stroke, cerebral ischemia, and subarachnoid hemorrhage. Nevertheless, it is not clear whether and how disrupting the Rho A/ROCK Ⅱ/MLC 2 signaling pathway changes the pathogenic processes of the blood–brain barrier(BBB) after intracerebral hemorrhage(ICH). The present investigation included the injection of rat caudal vein blood into the basal ganglia area to replicate the pathophysiological conditions caused by ICH. Methods: Scalp acupuncture(SA) therapy was performed on rats with ICH at the acupuncture point “Baihui”-penetrating “Qubin,” and the ROCK selective inhibitor fasudil was used as a positive control to evaluate the inhibitory effect of acupuncture on the Rho A/ROCK Ⅱ/MLC 2 signaling pathway. Post-assessments included neurological deficits, brain edema, Evans blue extravasation, Western blot, quantitative polymerase chain reaction, and transmission electron microscope imaging. Results: We found that ROCK Ⅱ acts as a promoter of the Rho A/ROCK Ⅱ/MLC 2 signaling pathway, and its expression increased at 6 h after ICH, peaked at 3 days, and then decreased at 7 days after ICH, but was still higher than the preintervention level. According to some experimental results, although 3 days is the peak, 7 days is the best time point for acupuncture treatment. Starting from 6 h after ICH, the neurovascular structure and endothelial cell morphology around the hematoma began to change. Based on the changes in the promoter ROCK Ⅱ, a 7-day time point was selected as the breakthrough point for treating ICH model rats in the main experiment. The results of this experiment showed that both SA at “Baihui”-penetrating “Qubin” and treatment with fasudil could improve the expression of endothelial-related proteins by inhibiting the Rho A/ROCK Ⅱ/MLC 2 signaling pathway and reduce neurological dysfunction, brain edema, and BBB permeability in rats. Conclusion: This study found that these experimental data indicated that SA at “Baihui”-penetrating “Qubin” could preserve BBB integrity and neurological function recovery after ICH by inhibiting Rho A/ROCK Ⅱ/MLC 2 signaling pathway activation and by regulating endothelial cell–related proteins. 展开更多
关键词 blood-brain barrier CAVEOLAE INTRACEREBRAL hemorrhage RhoA/ROCK II/MLC 2 signaling pathway SCALP ACUPUNCTURE
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Confined cobalt single-atom catalysts with strong electronic metal-support interactions based on a biomimetic self-assembly strategy
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作者 Bowen Guo Zekun Wang +3 位作者 lei zheng Guang Mo Hongjun Zhou Dan Luo 《Carbon Energy》 SCIE EI CAS CSCD 2024年第9期156-171,共16页
Designing high-performance and low-cost electrocatalysts for oxygen evolu-tion reaction(OER)is critical for the conversion and storage of sustainable energy technologies.Inspired by the biomineralization process,we ut... Designing high-performance and low-cost electrocatalysts for oxygen evolu-tion reaction(OER)is critical for the conversion and storage of sustainable energy technologies.Inspired by the biomineralization process,we utilized the phosphorylation sites of collagen molecules to combine with cobalt-based mononuclear precursors at the molecular level and built a three-dimensional(3D)porous hierarchical material through a bottom-up biomimetic self-assembly strategy to obtain single-atom catalysts confined on carbonized biomimetic self-assembled carriers(Co SACs/cBSC)after subsequent high-temperature annealing.In this strategy,the biomolecule improved the anchoring efficiency of the metal precursor through precise functional groups;meanwhile,the binding-then-assembling strategy also effectively suppressed the nonspecific adsorption of metal ions,ultimately preventing atomic agglomeration and achieving strong electronic metal-support interactions(EMSIs).Experimental characterizations confirm that binding forms between cobalt metal and carbonized self-assembled substrate(Co–O_(4)–P).Theoretical calculations disclose that the local environment changes significantly tailored the Co d-band center,and optimized the binding energy of oxygenated intermediates and the energy barrier of oxygen release.As a result,the obtained Co SACs/cBSC catalyst can achieve remarkable OER activity and 24 h durability in 1 M KOH(η10 at 288 mV;Tafel slope of 44 mV dec-1),better than other transition metal-based catalysts and commercial IrO_(2).Overall,we presented a self-assembly strategy to prepare transition metal SACs with strong EMSIs,providing a new avenue for the preparation of efficient catalysts with fine atomic structures. 展开更多
关键词 biomimetic self-assembly support electronic metal-support interactions oxygen evolution reaction single atoms catalysts
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Tackling application limitations of high-safetyγ-butyrolactone electrolytes:Exploring mechanisms and proposing solutions
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作者 Haojun Wu Zhangyating Xie +9 位作者 Guanjie Li lei zheng Zhiwei Zhao Jiarong He Yanbin Shen Jiahao Hu Zhangquan Peng Guiming Zhong Lidan Xing Weishan Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期193-201,I0005,共10页
Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Bu... Developing wide-temperature and high-safety lithium-ion batteries(LIBs)presents significant challenges attributed to the absence of suitable solvents possessing broad liquid range and non-flammability properties.γ-Butyrolactone(GBL)has emerged as a promising solvent;however,its incompatibility with graphite anode has hindered its application.This limitation necessitates a comprehensive investigation into the underlying mechanisms and potential solutions.In this study,we achieve a molecular-level understanding of the perplexing interphase formation process by employing in-situ spectroelectrochemical techniques and density function calculations.Our findings reveal that,even at high salt concentrations,GBL consistently occupies the primary Li^(+)solvation sheath,leading to extensive GBL decomposition and the formation of a high-impedance and inorganic-poor solid-electrolyte interphase(SEI)layer.Contrary to manipulating solvation structures,our research demonstrates that the utilization of filmforming additives with higher reduction potential facilitates the pre-establishment of a robust SEI film on the graphite anode.This approach effectively inhibits GBL decomposition and significantly enhances the battery's lifespan.This study provides the first reported intrinsic understanding of the unique GBLgraphite incompatibility and offers valuable insights for the development of wide-temperature and high-safety LIBs. 展开更多
关键词 γ-Butyrolactone/Graphite incompatibility Unique solvation structure SEI film Lithium-ion batteries
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Effectiveness and safety of early lens extraction during par plana vitrectomy for proliferative diabetes retinopathy with mild cataract:a randomized clinical trial
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作者 Wei-Bo Feng lei zheng +17 位作者 Ying-Qi Li Yong-Hao Li Guo-Ming Zhang Xian Wang Bing-Qian Liu Ling Jin Yi-Nuo Huang Yang-Fan Yang Zi-Dong Chen Da-Hui Ma Qing-Shan Chen Chao-Jun Qin Bing-Min Feng Zhu-Min Yang Xing Huang Cheng-Jie Yang Sheng-Hui Liu Ming-Xing Wu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第3期528-536,共9页
●AIM:To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR)compared to those of PPV with subsequent cataract surgery.●METHODS:T... ●AIM:To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR)compared to those of PPV with subsequent cataract surgery.●METHODS:This multicenter randomized controlled trial was conducted in three Chinese hospitals on patients with PDR,aged>45y,with mild cataracts.The participants were randomly assigned to the combined(PPV combined with simultaneously cataract surgery,i.e.,phacovitrectomy)or subsequent(PPV with subsequent cataract surgery 6mo later)group and followed up for 12mo.The primary outcome was the change in best-corrected visual acuity(BCVA)from baseline to 6mo,and the secondary outcomes included complication rates and medical expenses.●RESULTS:In total,129 patients with PDR were recruited and equally randomized(66 and 63 in the combined and subsequent groups respectively).The change in BCVA in the combined group[mean,36.90 letters;95%confidence interval(CI),30.35–43.45]was significantly better(adjusted difference,16.43;95%CI,8.77–24.08;P<0.001)than in the subsequent group(mean,22.40 letters;95%CI,15.55–29.24)6mo after the PPV,with no significant difference between the two groups at 12mo.The overall surgical risk of two sequential surgeries was significantly higher than that of the combined surgery for neovascular glaucoma(17.65%vs 3.77%,P=0.005).No significant differences were found in the photocoagulation spots,surgical time,and economic expenses between two groups.In the subsequent group,the duration of work incapacity(22.54±9.11d)was significantly longer(P<0.001)than that of the combined group(12.44±6.48d).●CONCLUSION:PDR patients aged over 45y with mild cataract can also benefit from early lens extraction during PPV with gratifying effectiveness,safety and convenience,compared to sequential surgeries. 展开更多
关键词 lens extraction pars plana vitrectomy proliferative diabetic retinopathy CATARACT simultaneously operations
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全程化血糖管理在改善无明显视网膜病变的2型糖尿病性白内障患者术后视力的效果分析:基于视觉电生理和OCTA研究
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作者 唐娟 兰芬 +7 位作者 孟林霞 张琴琴 戴传强 雷证 方其林 李盈 吴小利 李涛 《实用医学杂志》 CAS 北大核心 2024年第20期2888-2899,共12页
目的应用视觉电生理和光学相关断层扫描血管成像(OCTA)探讨无明显视网膜病变的2型糖尿病性白内障(DC)患者术前视网膜功能差异,以及全程化血糖管理在改善DC患者术后视力的临床应用效果。方法检测不同2型糖尿病(T2DM)病程、空腹血糖(FBG)... 目的应用视觉电生理和光学相关断层扫描血管成像(OCTA)探讨无明显视网膜病变的2型糖尿病性白内障(DC)患者术前视网膜功能差异,以及全程化血糖管理在改善DC患者术后视力的临床应用效果。方法检测不同2型糖尿病(T2DM)病程、空腹血糖(FBG)、糖化血红蛋白(HbA1c)状态下,DC患者术前与术后视觉电生理(N75、P100、明视FERG、暗视FERG)、视盘旁视网膜神经纤维层厚度(pRNFL)和视盘旁放射状毛细血管网血流密度(ppVD)变化差异,以及全程化血糖管理干预情况下上述数据变化趋势。结果随着T2DM病程延长、FBG和HbA1c升高,术后各时间点单独分析,患者N75和P100潜伏期逐渐变长,暗视FERG、暗视FERG、p RNFL和ppVD数值均逐渐下降,同时患者术后最佳矫正视力均逐渐下降(P<0.05)。与术后1周比较,A组(未采取全程化血糖管理)视力在术后1个月和术后3个月逐渐增加,但术后1年时呈下降趋势,B组(采取全程化血糖管理)术后1个月时视力逐渐趋于稳定,且术后各时间点B组视力均优于A组;结果显示A组N75和P100均高于B组,同时A组明视FERG、暗视FERG、pRNFL和ppVD(%)均低于B组,并且A组患者N75和P100术后各时间点呈现逐渐延长趋势,明视FERG、暗视FERG、pRNFL和ppVD(%)呈现逐渐下降趋势,但B组患者上述数据在DC术后3个月逐渐趋于稳定,接近于该组术前水平(P<0.05)。在全程化血糖管理状态下,术后1周时N75和P100虽然均达到最长时间,明视FERG和暗视FERG、pp VD下降至最低,pRNFL呈现高度水肿状态,但术后1个月和术后3个月时间点N75、P100和pRNFL呈现逐渐下降趋势,明视FERG、暗视FERG和ppVD(%)逐渐上升(P<0.05),术后3个月至1年各时间点比较,上述指标整体趋势稳定,接近于术前水平(P>0.05)。结论基于视觉电生理和OCTA定量分析,在无明显视网膜病变的DC患者中,随着糖尿病病情加重,患者视网膜功能呈现下降趋势,但全程化血糖管理可以有效改善DC患者视网膜功能,提高术后视觉质量。 展开更多
关键词 2型糖尿病 视觉电生理 OCTA 全程化血糖管理 视网膜功能
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Expression of cyclin-dependent kinase 9 is positively correlated with the autophagy level in colon cancer
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作者 lei zheng Jia Lu Da-Lu Kong 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第2期314-330,共17页
BACKGROUND Cyclin-dependent kinase 9(CDK9)expression and autophagy in colorectal cancer(CRC)tissues has not been widely studied.CDK9,a key regulator of transcription,may influence the occurrence and progression of CRC... BACKGROUND Cyclin-dependent kinase 9(CDK9)expression and autophagy in colorectal cancer(CRC)tissues has not been widely studied.CDK9,a key regulator of transcription,may influence the occurrence and progression of CRC.The expression of auto-phagy-related genes BECN1 and drug resistance factor ABCG2 may also play a role in CRC.Under normal physiological conditions,autophagy can inhibit tumorigenesis,but once a tumor forms,autophagy may promote tumor growth.Therefore,understanding the relationship between autophagy and cancer,partic-ularly how autophagy promotes tumor growth after its formation,is a key motivation for this research.AIM To investigate the relationship between CDK9 expression and autophagy in CRC,assess differences in autophagy between left and right colon cancer,and analyze the associations of autophagy-related genes with clinical features and prognosis.METHODS We collected tumor tissues and paracarcinoma tissues from colon cancer patients with liver metastasis to observe the level of autophagy in tissues with high levels of CDK9 and low levels of CDK9.We also collected primary tissue from left and right colon cancer patients with liver metastasis to compare the autophagy levels and the expression of BECN1 and ABCG2 in the tumor and paracarcinoma tissues.RESULTS The incidence of autophagy and the expression of BECN1 and ABCG2 were different in left and right colon cancer,and autophagy might be involved in the occurrence of chemotherapy resistance.Further analysis of the rela-tionship between the expression of autophagy-related genes CDK9,ABCG2,and BECN1 and the clinical features and prognosis of colorectal cancer showed that the high expression of CDK9 indicated a poor prognosis in colorectal cancer.CONCLUSION This study laid the foundation for further research on the combination of CDK9 inhibitors and autophagy inhibitors in the treatment of patients with CRC. 展开更多
关键词 AUTOPHAGY TUMORIGENESIS Tumor tissue Paracarcinoma tissue EXPRESSION Left/right colon cancer
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Correlation and predictive value of pathological complete response and ultrasound characteristic parameters in neoadjuvant chemotherapy for breast
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作者 lei zheng Li-Xian Yang +3 位作者 Jing-Yi Liu Zhe Jiang Xiao-Wei Li Peng-Peng Pu 《World Journal of Clinical Cases》 SCIE 2024年第23期5320-5328,共9页
BACKGROUND Breast cancer ranks as one of the most prevalent malignant tumors among women,significantly endangering their health and lives.While radical surgery has been a pivotal method for halting disease progression... BACKGROUND Breast cancer ranks as one of the most prevalent malignant tumors among women,significantly endangering their health and lives.While radical surgery has been a pivotal method for halting disease progression,it alone is insufficient for enhancing the quality of life for patients.AIM To investigate the correlation between ultrasound characteristic parameters of breast cancer lesions and clinical efficacy in patients undergoing neoadjuvant chemotherapy(NAC).METHODS Employing a case-control study design,this research involved 178 breast cancer patients treated with NAC at our hospital from July 2019 to June 2022.According to the Miller-Payne grading system,the pathological response,i.e.efficacy,of the NAC in the initial breast lesion after NAC was evaluated.Of these,59 patients achieved a pathological complete response(PCR),while 119 did not(non-PCR group).Ultrasound characteristics prior to NAC were compared between these groups,and the association of various factors with NAC efficacy was analyzed using univariate and multivariate approaches.RESULTS In the PCR group,the incidence of posterior echo attenuation,lesion diameter≥2.0 cm,and Alder blood flow grade≥II were significantly lower compared to the non-PCR group(P<0.05).The area under the curve values for predicting NAC efficacy using posterior echo attenuation,lesion diameter,and Alder grade were 0.604,0.603,and 0.583,respectively.Also,rates of pathological stage II,lymph node metastasis,vascular invasion,and positive Ki-67 expression were significantly lower in the PCR group(P<0.05).Logistic regression analysis identified posterior echo attenuation,lesion diameter≥2.0 cm,Alder blood flow grade≥II,pathological stage III,vascular invasion,and positive Ki-67 expression as independent predictors of poor response to NAC in breast cancer patients(P<0.05).CONCLUSION While ultrasound characteristics such as posterior echo attenuation,lesion diameter≥2.0 cm,and Alder blood flow grade≥II exhibit limited predictive value for NAC efficacy,they are significantly associated with poor response to NAC in breast cancer patients. 展开更多
关键词 Breast cancer ULTRASOUND Neoadjuvant chemotherapy EFFICACY Pathological complete response
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考虑静态电压稳定性的城市电网储能优化配置研究
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作者 闫大威 张天宇 +4 位作者 李天翔 王魁 罗涛 雷铮 肖迁 《浙江电力》 2024年第7期76-85,共10页
伴随新能源规模化接入城市电网,电力系统逐步呈现供需时空错配形势,将导致其静态电压稳定性逐步下降,危及用电安全。为此,提出一种供需时空错配形势下计及静态电压稳定性的新型城市电网储能优化配置方法。首先,分析新能源规模化接入下... 伴随新能源规模化接入城市电网,电力系统逐步呈现供需时空错配形势,将导致其静态电压稳定性逐步下降,危及用电安全。为此,提出一种供需时空错配形势下计及静态电压稳定性的新型城市电网储能优化配置方法。首先,分析新能源规模化接入下城市电网供需时空错配特征,分别建立供需空间、时间错配评估指标;其次,基于输电线路潮流方程,利用一元二次方程判别式分析潮流解的个数,提出一种城市电网静态电压稳定性评估指标;然后,加权考虑上述供需时空错配及静态电压稳定性评估指标,建立储能设备优化配置模型;最后,通过仿真验证了所提方法的有效性和优越性。 展开更多
关键词 供需时空错配 静态电压稳定性 新型城市电网 储能优化配置
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中国式现代化进程中的青年发展:出场、在场、路径
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作者 雷铮 《北京青年研究》 2024年第4期20-30,共11页
中国青年在中国式现代化进程中觉醒和发展,逐渐成为中国式现代化的主体和先锋力量。中国青年与中国式现代化同向同行、良性互促,体现在中国青年发展与中国式现代化具有同构性,以及中国青年的内在特点与中国式现代化特征具有耦合性。现... 中国青年在中国式现代化进程中觉醒和发展,逐渐成为中国式现代化的主体和先锋力量。中国青年与中国式现代化同向同行、良性互促,体现在中国青年发展与中国式现代化具有同构性,以及中国青年的内在特点与中国式现代化特征具有耦合性。现代化孕育了青年,促进了青年的觉醒和成熟;青年的发展同时又推动了现代化前进的步伐。要实现青年的高质量发展,以青年现代化推进中国式现代化,需要从四个方面入手:坚定理想信念,用党的创新理论铸魂育人;练就过硬本领,激发青年人才队伍优势;关注青年问题,优化青年发展的生态环境;完善青年政策,构建青年发展的工作机制。 展开更多
关键词 中国式现代化 青年 同向同行 实践路径
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广西北部湾经济区乡村性评价与时空分异研究
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作者 雷征 王睿 梁春丽 《地理空间信息》 2024年第7期12-17,共6页
广西北部湾经济区是我国西南重要的国际区域经济合作区,辖区面积大、乡村人口多,测算评价其乡村性,掌握县域间乡村发展差异,对促进乡村转型发展、缩小城乡发展差距具有重要意义。通过测算各县域乡村性指数,借助ArcGIS软件空间分析功能,... 广西北部湾经济区是我国西南重要的国际区域经济合作区,辖区面积大、乡村人口多,测算评价其乡村性,掌握县域间乡村发展差异,对促进乡村转型发展、缩小城乡发展差距具有重要意义。通过测算各县域乡村性指数,借助ArcGIS软件空间分析功能,对各县域乡村性时序特征和空间分布进行分析。结果表明:①广西北部湾经济区乡村性较强,总体呈下降趋势;②2000—2020年强乡村性与弱乡村性县域数量此消彼长,县域间乡村发展水平差距拉大;③强乡村性和较强乡村性县域主要分布在桂西喀斯特地貌山区、大明山区和十万大山区,较弱乡村性和弱乡村性县域零散分布在边境和沿海地区,县域乡村性空间分异明显。 展开更多
关键词 乡村性 时空分异 县域 广西北部湾经济区
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广西北部湾经济区土地利用碳排放与脱钩分析
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作者 雷征 王易 《地理空间信息》 2024年第9期94-99,共6页
基于2010—2020年土地利用数据、经济增长数据和能源消费数据,采用碳排放系数法和Tapio脱钩模型计算了广西北部湾经济区净碳排放总量,分析了与经济增长的脱钩关系。研究表明,广西北部湾经济区土地利用净碳排放量呈不断增长趋势,净碳排... 基于2010—2020年土地利用数据、经济增长数据和能源消费数据,采用碳排放系数法和Tapio脱钩模型计算了广西北部湾经济区净碳排放总量,分析了与经济增长的脱钩关系。研究表明,广西北部湾经济区土地利用净碳排放量呈不断增长趋势,净碳排放量和碳排放强度总体呈东北高西南低的空间分布特征;与经济增长的关系在2015年和2020年处于扩张性负脱钩状态,其余年份处于弱脱钩状态,总体脱钩状态良好。 展开更多
关键词 土地利用碳排放 经济增长 脱钩分析 广西北部湾经济区
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广西建设用地碳排放测算及时空演变特征研究
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作者 雷征 卢聪 《国土资源导刊》 2024年第3期61-67,共7页
通过测算广西建设用地碳排放量,分析碳排放强度,研究广西各市碳排放空间差异和时序特征,为低碳目标下改进土地利用模式、优化土地利用结构、制定差别化低碳土地利用调控政策提供参考。研究结果:(1)广西建设用地碳排放量逐年增加,煤炭消... 通过测算广西建设用地碳排放量,分析碳排放强度,研究广西各市碳排放空间差异和时序特征,为低碳目标下改进土地利用模式、优化土地利用结构、制定差别化低碳土地利用调控政策提供参考。研究结果:(1)广西建设用地碳排放量逐年增加,煤炭消费始终是最主要的碳排放来源;(2)广西建设用地碳排放强度在持续增长并有加重的趋势;(3)广西各县(区)建设用地碳排放量在不同时段的空间布局变化明显。研究结论:广西碳减排任务压力比较大,建议从改善能源利用方式、控制建设用地规模、调整优化产业结构等方面采取措施控制建设用地碳排放,推动低碳经济发展。 展开更多
关键词 建设用地 碳排放 时空演变特征 广西
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广西实用性村庄规划快速编制关键技术研究与应用示范
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作者 郎荣庆 黎仕玉 +1 位作者 雷征 王睿 《城市建筑空间》 2024年第3期100-102,共3页
在乡村振兴战略背景下,目前广西全区村庄规划面临一系列难点,亟需寻求创新方式破解当前困局。结合村庄规划业务全流程,提出“一个调研APP、一个规划编制系统、一个支撑环境”的技术创新方式,基于Harmony OS系统研发调研APP,基于Arc GIS... 在乡村振兴战略背景下,目前广西全区村庄规划面临一系列难点,亟需寻求创新方式破解当前困局。结合村庄规划业务全流程,提出“一个调研APP、一个规划编制系统、一个支撑环境”的技术创新方式,基于Harmony OS系统研发调研APP,基于Arc GIS软件研发规划编制系统,基于相关数据平台搭建“支撑环境”,构建全流程信息化作业模式并应用于试点地区,通过技术应用示范效果分析,分别从大众参与度、规划编制效率两方面验证其可行性。 展开更多
关键词 乡村振兴 村庄规划 快速编制 应用示范
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Assessing and Improving the Quality of Undergraduates in Preschool Education Programs in China:The Course Experience
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作者 Linxi Zhang lei zheng Ying Zhou 《教育技术与创新》 2024年第3期31-46,共16页
This study investigated the current status of course satisfaction among 416 undergraduate students majoring in preschool education from four universities in China.And it explored the predictive effects of five influen... This study investigated the current status of course satisfaction among 416 undergraduate students majoring in preschool education from four universities in China.And it explored the predictive effects of five influencing factors(teacher instruction,course management,course setting,course environment,and course resources)on student satisfaction.Through SPSS data analysis,the findings revealed that:1.the mean value of course experience was M=3.861(out of 5);2.there were differences in the satisfaction of undergraduate students'course experience by different background variables;3.course,course resources,and loyalty had significant predictive power on undergraduate students'satisfaction with course experience;4.instructor instruction(TI)did not significantly predict students'satisfaction with course experience(SCES)(p>0.001);5.Faculty instruction(TI)in this study had the highest mean satisfaction score(M=4.191)and the mean satisfaction score was only(M=3.861).The results show that the current status of course satisfaction among Chinese preschool undergraduates is at an moderate level,and there is more space for improvement;although students'satisfaction with teacher instruction(TI)is high,effective teacher instruction does not have a substantial impact on the acquisition of SCES or general competencies,and this passive learning and teaching style leads to a lack of independent learning and active participation among Chinese preschool undergraduate students. 展开更多
关键词 Higher education Preschool education program SATISFACTION Course experience
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自紧式V形金属密封特性及悬臂结构影响 被引量:1
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作者 张大伟 雷征 +3 位作者 闫方琦 田冲 王晨浩 李智军 《机械科学与技术》 CSCD 北大核心 2023年第7期1114-1119,共6页
自紧式V形金属密封在液体火箭发动机中有广泛应用,然而不同使用环境下的结构形式、几何参数、材料选用等变化繁多。基于工况和空间约束设计了一种V形金属密封结构,并基于ABAQUS平台,建立V形金属密封装配-承压-卸载-拆卸全工作过程有限... 自紧式V形金属密封在液体火箭发动机中有广泛应用,然而不同使用环境下的结构形式、几何参数、材料选用等变化繁多。基于工况和空间约束设计了一种V形金属密封结构,并基于ABAQUS平台,建立V形金属密封装配-承压-卸载-拆卸全工作过程有限元模型,研究工作全过程的密封特性和可控几何参数影响。结果表明:密封唇高温承压后屈服变形并持续增加属塑性变形,密封悬臂处塑性变形先增加后保持不变,具备良好自紧特性,拆卸分离后密封唇处无明显局部压痕、密封件回弹率为88.4%,可保证密封性能和重复使用性;回弹率随两悬臂间内张角α和悬臂内外侧张角β增加而增加,β对接触压强和回弹率影响大于α;通过几何参数优化,可进一步提高回弹率。 展开更多
关键词 高压静密封 自紧式密封 V形金属密封 几何参数影响 有限元分析
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喹啉类化合物的合成及其结构对阴离子比色传感性能影响研究——介绍一个研究型综合实验项目
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作者 黄磊 郑蕾 +2 位作者 包磊 聂丽 傅绪成 《大学化学》 CAS 2023年第11期163-170,共8页
介绍了一个研究型综合实验项目——喹啉类化合物的合成及其结构对阴离子比色传感性能影响研究。在本实验中,学生将学习并掌握喹啉类杂环化合物及其衍生物的合成方法以及表征手段。学生在理解有机小分子传感识别原理的基础上,学会利用紫... 介绍了一个研究型综合实验项目——喹啉类化合物的合成及其结构对阴离子比色传感性能影响研究。在本实验中,学生将学习并掌握喹啉类杂环化合物及其衍生物的合成方法以及表征手段。学生在理解有机小分子传感识别原理的基础上,学会利用紫外-可见吸收光谱仪研究喹啉类化合物作为探针(P1、P2、P3)对阴离子传感识别性能。通过Origin软件处理的光谱数据以及可视化的比色图像,让学生更加直观地比较不同探针的阴离子传感识别性能,深入理解探针的分子结构影响和控制其传感性能的重要性。 展开更多
关键词 综合实验 喹啉类化合物 比色传感 探针
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软土地区沟槽浅基坑机械化施工简易支护研究 被引量:1
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作者 邵冰然 张海威 +5 位作者 唐继朋 秦涛 白苏娜 雷铮 左焦 于江浩 《建筑结构》 北大核心 2023年第S02期2636-2640,共5页
电力电缆工程浅基坑机械化施工时,无专项支护设计方案,多存在简易支护措施不当或过度使用钢板桩支护的乱象发生。参照相关规程规范并结合实际工程经验,对浅基坑的边界条件进行研究梳理,确定浅基坑支挡结构安全等级、超载取值等参数。通... 电力电缆工程浅基坑机械化施工时,无专项支护设计方案,多存在简易支护措施不当或过度使用钢板桩支护的乱象发生。参照相关规程规范并结合实际工程经验,对浅基坑的边界条件进行研究梳理,确定浅基坑支挡结构安全等级、超载取值等参数。通过位于天津典型软土地区的工程实例,以控制变量法分别对超限值、地基加固以及钢板桩内撑的影响效果进行研究,确定拉森钢板桩支护结构的形式选择,对沟槽浅基坑支护优化设计给予一定的技术引导与参考。 展开更多
关键词 机械化施工 典型软土地区 边界条件 拉森钢板桩支挡结构
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