期刊文献+
共找到9篇文章
< 1 >
每页显示 20 50 100
Fabrication and Mechanical Testing of Ultralight Folded Lattice-CoreSandwich Cylinders 被引量:6
1
作者 wanxin li Qing Zheng +1 位作者 Hualin Fan Bin Ji 《Engineering》 SCIE EI 2020年第2期196-204,共9页
In this research,two novel folded lattice-core sandwich cylinders were designed,manufactured,and tested.The lattice core has periodic zigzag corrugations,whose ridges and valleys are directed axially or circumferentia... In this research,two novel folded lattice-core sandwich cylinders were designed,manufactured,and tested.The lattice core has periodic zigzag corrugations,whose ridges and valleys are directed axially or circumferentially.Free vibration and axial compression experiments were performed to reveal the fundamental frequency,free vibration modes,bearing capacity,and failure mode of the cylinder.A folded lattice core effectively restricts local buckling by reducing the dimension of the local skin periodic cell,and improves the global buckling resistance by enhancing the shear stiffness of the sandwich core.The cylinders fail at the mode of material failure and possess excellent load-carrying capacity.An axially directed folded sandwich cylinder has greater load-carrying capacity,while a circumferentially directed folded sandwich cylinder has higher fundamental frequencies.These two types of folded lattices provide a selection for engineers when designing a sandwich cylinder requiring strength or vibration.This research also presents a feasible way to fabricate a large-dimensional folded structure and promote its engineering application. 展开更多
关键词 Folded lattice-core SANDWICH CYLINDER FABRICATION MECHANICAL TESTING
下载PDF
Examining the Influence of Fertility Policy Adjustments on Gender Equality in China During the Period of Exceptionally Slow Population Growth
2
作者 Xueyan Yang wanxin li Rui li 《China CDC weekly》 SCIE CSCD 2023年第27期605-608,共4页
The Chinese population is entering a new stage of development,marked by the fertility intentions of women of childbearing age continuing to decline and concerns over their consistently low fertility rates.The number o... The Chinese population is entering a new stage of development,marked by the fertility intentions of women of childbearing age continuing to decline and concerns over their consistently low fertility rates.The number of newborns has been decreasing annually,with 2022 figures falling below 10 million for the first time since the founding of the People’s Republic of China,resulting in negative population growth(1).Currently,China’s population over the age of 60 years is nearing 300 million and is projected to surpass 20%of the total population during the 14th Five-Year Plan period. 展开更多
关键词 POPULATION FERTILITY annually
原文传递
Inflammation as a Mediator of Microbiome Dysbiosis-Associated DNA Methylation Changes in Gastric Premalignant Lesions
3
作者 lingjun Yan wanxin li +4 位作者 Fenglin Chen Junzhuo Wang Jianshun Chen Ying Chen Weimin Ye 《Phenomics》 2023年第5期496-501,共6页
Evidence for the influence of chronic inflammation induced by microbial dysbiosis on aberrant DNA methylation supports a plausible connexion between disordered microbiota and precancerous lesions of gastric cancer(PLG... Evidence for the influence of chronic inflammation induced by microbial dysbiosis on aberrant DNA methylation supports a plausible connexion between disordered microbiota and precancerous lesions of gastric cancer(PLGC).Here,a comprehensive study including multi-omics data was performed to estimate the relationships amongst the gastric microbiome,inflammatory proteins and DNA methylation alterations and their roles in PLGC development.The results demonstrated that gastric dysbacteriosis increased the risk of PLGC and DNA methylation alterations in related tumour suppressor genes.Seven inflammatory biomarkers were identified for antrum and corpus tissues,respectively,amongst which the expression levels of several biomarkers were significantly correlated with the microbial dysbiosis index(MDI)and methylation status of specific tumour suppressor genes.Notably,mediation analysis revealed that microbial dysbiosis partially contributed to DNA methylation changes in the stomach via the inflammatory cytokines C-C motif chemokine 20(CCL20)and tumour necrosis factor receptor superfamily member 9(TNFRSF9).Overall,these results may provide new insights into the mechanisms that might link the gastric microbiome to PLGC. 展开更多
关键词 Gastric premalignant lesions Microbiome dysbiosis INFLAMMATION DNA methylation Mediation analysis
原文传递
Effects of ultrasonication on the DBP formation and toxicity during chlorination of saline wastewater effluents 被引量:1
4
作者 Yu li wanxin li +1 位作者 Xiangru Zhang Jingyi Jiang 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2022年第7期326-335,共10页
Chlorine disinfection of saline wastewater effluents rich in bromide and iodide forms relatively toxic brominated and iodinated disinfection byproducts(DBPs). Ultrasonication is a relatively new water treatment techno... Chlorine disinfection of saline wastewater effluents rich in bromide and iodide forms relatively toxic brominated and iodinated disinfection byproducts(DBPs). Ultrasonication is a relatively new water treatment technology, and it is less sensitive to suspended solids in wastewaters. In this study, we examined the effects of ultrasonication(in terms of reactor type and combination mode with chlorination) on the DBP formation and toxicity in chlorinated primary and secondary saline wastewater effluents. Compared with the chlorinated wastewater effluent samples without ultrasonication, ultrasonic horn pretreatment of the wastewater effluent samples reduced the total organic halogen(TOX) levels in chlorination by ~30%, but ultrasonic bath pretreatment of the wastewater samples did not significantly change the TOX levels in chlorination, which might be attributed to the higher energy utilization and decomposition extent of organic DBP precursors in the ultrasonic horn reactor. Moreover, the TOX levels in the chlorinated samples with ultrasonic horn pretreatment(USH–chlorination), simultaneous treatment(chlorination + USH) and subsequent treatment(chlorination–USH) were also significantly reduced, with the maximum TOX reductions occurring in the samples with ultrasonic horn pretreatment. A toxicity index was calculated by weighting and summing the levels of total organic chlorine, total organic bromine and total organic iodine in each treated sample. The calculated toxicity index values of the chlorinated wastewater effluent samples followed a descending rank order of “chlorination” > “chlorination + USH” > “chlorination–USH” > “USH–chlorination”, with the lowest toxicity occurring in the samples with ultrasonic horn pretreatment. Then, a developmental toxicity bioassay was conducted for each treated sample. The measured toxicity index values of the chlorinated wastewater samples followed the same descending rank order. 展开更多
关键词 Disinfection byproducts DBPS CHLORINATION Ultrasonication Developmental toxicity
原文传递
MEN2A/MEN2B家系RET胚系突变携带者“分级预警制”与甲状腺预防切除术的研究(附7例报道)
5
作者 齐欣萌 李婉欣 +2 位作者 黄俊伟 黄志刚 陈晓红 《中华耳鼻咽喉头颈外科杂志》 CSCD 北大核心 2023年第3期212-217,共6页
目的探讨对多发性内分泌腺瘤病(multiple endocrine neoplasia,MEN)2A/2B人群实施甲状腺预防性切除术的合理时机。方法首都医科大学附属北京同仁医院甲状腺头颈外科于2015年5月至2021年8月,动态随访MEN2A/MEN2B家系中RET基因携带者,依... 目的探讨对多发性内分泌腺瘤病(multiple endocrine neoplasia,MEN)2A/2B人群实施甲状腺预防性切除术的合理时机。方法首都医科大学附属北京同仁医院甲状腺头颈外科于2015年5月至2021年8月,动态随访MEN2A/MEN2B家系中RET基因携带者,依据“分级预警制”(即依次通过基因检测、降钙素指标和超声检查的评估)鼓励高危者进行预防性甲状腺全切除术,实际完成7例,男3例,女4例,年龄为7~29岁。根据2015年美国甲状腺协会(ATA)指南中列出的风险分层,分别为最高风险(highest,HST)、高风险(high,H)各2例,中等风险(modest,MOD)3例。3例患者的降钙素术前保持为正常范围内,4例患者术前降钙素水平升高。7例患者均接受了甲状腺切除术,4例患者同期进行了Ⅵ区淋巴结探查或预防性清扫术。结果从动员手术到实施手术时间为2~37个月,平均15.1个月。除1例病理回报为C细胞增生,其余6例均为甲状腺髓样癌。术后随访2~82个月,平均随访时间为38.4个月。术后血清降钙素降至正常水平,达到生化治愈,定期超声检查均无甲状腺癌复发。7例患者术后均无严重并发症发生,无明显甲状腺功能紊乱,且患儿身高、体重等指标与同龄人相仿,生长发育正常。结论对于有MEN2A/MEN2B家族史的健康人群,应用“分级预警制”的综合判断,在严格筛选和密切监测的基础上,把握合理时机,可开展甲状腺预防性切除术。 展开更多
关键词 甲状腺肿瘤 髓样 RET突变 多发性内分泌腺瘤病2型 中国健康人群 甲状腺预防性切除术
原文传递
霾污染天气大气微生物气溶胶特性的研究进展 被引量:16
6
作者 李彦鹏 刘鹏霞 +4 位作者 谢铮胜 范春兰 路瑞 李婉欣 邓顺熙 《科学通报》 EI CAS CSCD 北大核心 2018年第10期940-953,共14页
自从2013年以来,中国霾事件频发,霾污染已经成为全国人民广泛关注的环境问题之一.霾污染的本质是大气细颗粒物污染.大气颗粒物的生物成分(即生物气溶胶)与其化学成分一样,不仅对空气质量和人群健康具有潜在威胁,而且对全球气候变化以及... 自从2013年以来,中国霾事件频发,霾污染已经成为全国人民广泛关注的环境问题之一.霾污染的本质是大气细颗粒物污染.大气颗粒物的生物成分(即生物气溶胶)与其化学成分一样,不仅对空气质量和人群健康具有潜在威胁,而且对全球气候变化以及大气物理化学过程也具有间接影响.然而,目前学术界对大气颗粒物的生物成分及其性质的研究相对滞后,尤其是对霾污染天气大气颗粒物中微生物的多样性、丰度及其时空变异特性等基本科学问题认识不足.因此,本文综述了目前霾污染天气大气微生物气溶胶的研究现状,结合我们的研究着重阐述了在不同霾污染程度下生物气溶胶的浓度、粒径分布与群落结构特性,以及空气污染和环境因子对生物气溶胶分布的影响机理等方面存在的问题.最后,给出了未来霾污染过程生物气溶胶研究应主要开展的5个方面的工作展望,以期为深入理解霾天生物气溶胶的来源、变化机理以及评估不同空气质量的健康影响提供参考. 展开更多
关键词 霾污染 微生物气溶胶 浓度 粒径分布 群落结构
原文传递
儿童人际关系及家庭与社会结构的影响研究
7
作者 李万新 李向明 +1 位作者 孙春柳 刘嘉慧 《中国公共政策评论》 2012年第1期141-154,共14页
本文以小学六年级学童及其家长为研究对象,运用核心小组和问卷的方法了解孩子在家庭和学校中与父母及同伴的互动关系的特征,并运用因子分析的方法定义和测量儿童人际关系的维度。然后运用回归分析的方法,分析户籍、独生子女等社会与家... 本文以小学六年级学童及其家长为研究对象,运用核心小组和问卷的方法了解孩子在家庭和学校中与父母及同伴的互动关系的特征,并运用因子分析的方法定义和测量儿童人际关系的维度。然后运用回归分析的方法,分析户籍、独生子女等社会与家庭结构特征对儿童关系资本和人际关系满意度的影响。研究发现,性别、是否独生子女、是否拥有深圳市户籍显著影响儿童的关系资本,但对其人际关系满意度并无显著影响。而亲子互动、学校参与能显著提高儿童对其人际关系的满意度。 展开更多
关键词 儿童 儿童人际关系 家庭 社会结构 影响
原文传递
嗜水气单胞菌中转录因子AHA_1581对细菌生理功能调控机制 的研究 被引量:4
8
作者 李碗芯 赵怡扬 +1 位作者 林玲 林向民 《微生物学报》 CAS CSCD 北大核心 2021年第11期3594-3606,共13页
【目的】LuxR家族转录因子能够抑制或刺激不同功能类型基因的表达,来维持细胞功能的稳定性。嗜水气单胞菌是水产养殖中重要的致病菌之一,目前对该菌中的LuxR家族转录因子功能的研究还较少。【方法】本研究利用含有sacB标记的自杀载体pRE... 【目的】LuxR家族转录因子能够抑制或刺激不同功能类型基因的表达,来维持细胞功能的稳定性。嗜水气单胞菌是水产养殖中重要的致病菌之一,目前对该菌中的LuxR家族转录因子功能的研究还较少。【方法】本研究利用含有sacB标记的自杀载体pRE112和同源重组技术敲除LuxR家族转录因子AHA_1581基因。【结果】生理表型测定结果发现,ΔAHA_1581的运动与胞外蛋白的酶活增强、生物被膜形成能力降低,且耐受低温、卡那霉素、庆大霉素胁迫,但是对K_(2)Cr_(2)O_(7)更加敏感。进一步对野生型Ah和ΔAHA_1581的定量蛋白质组学分析,共鉴定到2654个蛋白,其中59个蛋白下调表达,142个蛋白上调表达。生物信息学分析表明AHA_1581参与调控双组分调节系统、丙酮酸代谢、碳代谢、TCA循环等细菌重要生理过程,以及细菌耐药基因和毒力因子的差异表达。【结论】了解AHA_1581基因在调控细菌毒力以及生物过程中所起的重要作用,对预防和控制嗜水气单胞菌引起疾病的发生和传播可能具有重要的科学意义。 展开更多
关键词 嗜水气单胞菌 LuxR家族转录因子 AHA_1581 定量蛋白质组学 生理功能
原文传递
Population dynamics in northwestern China
9
作者 Xueyan Yang wanxin li +3 位作者 Wen Jing Chezhuo Gao Rui li Yuqi He 《China Population and Development Studies》 2021年第4期107-123,共17页
This article analyzes the population dynamics in northwestern China from roughly 2010 to 2020.The area’s dynamics showed a slow,stable increase in population size,a stable increase in the population of non-Han ethnic... This article analyzes the population dynamics in northwestern China from roughly 2010 to 2020.The area’s dynamics showed a slow,stable increase in population size,a stable increase in the population of non-Han ethnic groups,which increased at a more rapidly than the Han population,and population rejuvenation coupled with a population structure that aged.The biological sex structure fluctuated within a balanced range in northwestern China.Urbanization advanced in northwestern China,throughout this period,but the area’s level of urbanization is still significantly lower than the average level of urbanization nationally. 展开更多
关键词 FERTILITY Ethnic structure Age structure URBANIZATION Northwestern China
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部