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连续换相失败对大电网功角稳定影响分析

山东电力技术 2024年第4期51卷 56-63页

作者：朱元振马欢姜力扬周宁蒋哲国网山东省电力公司电力科学研究院山东济南250003 国网山东省电力公司烟台供电公司山东烟台264001

连续换相失败对交直流大电网的安全稳定运行存在严重威胁,容易引发跨大区电网的连锁故障。采用理论分析和实际电网仿真相结合的方式研究连续换相失败对交流系统功角稳定性的影响。首先从交直流系统无功功率交换的角度,分析连续换相失败... 详细信息

连续换相失败对交直流大电网的安全稳定运行存在严重威胁,容易引发跨大区电网的连锁故障。采用理论分析和实际电网仿真相结合的方式研究连续换相失败对交流系统功角稳定性的影响。首先从交直流系统无功功率交换的角度,分析连续换相失败的形成原因。然后以简化的三区域交直流互联系统为例,基于等面积法则分析连续换相失败过程中交流系统同步发电机相对功角的变化情况。最后,仿真分析当绍兴换流站发生连续换相失败时,送端电网和受端电网功角变化情况。仿真结果表明,连续换相失败在短时间内对交流系统造成多次能量冲击,长时间的连续换相失败会造成交流系统功角失稳。

关键词：连续换相失败功角稳定等面积法则连锁故障

纯电动城市客车小电量配置快速充电运营模式分析

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客车技术与研究 2020年第2期42卷 28-30页

作者：范志航杨国森赵鹏辉王毅马黎阳尚岩郑州宇通客车股份有限公司郑州450016

现有纯电动城市客车为满足国家补贴政策,均配置较大的电池能量。车辆若配置较小电池能量,通过快速补电保持运营里程,可有效降低车辆购置成本,并使得综合成本降低。

关键词：快速充电运营模式小电量配置纯电动城市客车

贵州遵义市280名仡佬族和苗族学龄儿童龋病调查分析

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全科口腔医学电子杂志 2019年第19期6卷 17-19页

作者：涂曾辉马力扬郑茜罗惠芳张洪荣西北民族大学口腔医学院

目的比较贵州省遵义市务川县仡佬族和苗族学龄儿童的口腔健康情况及对口腔保健知识的了解情况,为仡佬族和苗族儿童龋病防治工作提供参考。方法采取按照民族、男女分层、整群抽样的方法,对贵州省遵义市务川仡佬族苗族自治县茅天镇280名... 详细信息

目的比较贵州省遵义市务川县仡佬族和苗族学龄儿童的口腔健康情况及对口腔保健知识的了解情况,为仡佬族和苗族儿童龋病防治工作提供参考。方法采取按照民族、男女分层、整群抽样的方法,对贵州省遵义市务川仡佬族苗族自治县茅天镇280名学龄儿童进行龋病调查。结果280名学龄儿童的乳牙总患龋率为74.29%,仡佬族和苗族学龄儿童乳牙龋病率分别为70.19%和79.83%、龋均分别为2.58和3.76;仡佬族和苗族学龄儿童恒牙龋病率分别为17.39%和24.37%、龋均分别为0.24和0.38;仡佬族和苗族乳牙龋均之间差异有统计学意义(t=3.629,P=0.000),苗族女生恒牙患龋率低于男生(χ^=7.982,P=0.005),苗族女生恒牙龋均高于男生(t=3.446,P=0.000),其他指标差异均无统计学意义(P>0.05)。另外所有调查样本数据中龋充填率均为0。结论贵州省遵义市务川县仡佬族与苗族学龄儿童的患龋率均较高,而且调查样本数据中龋充填率均为0,需要进一步加强口腔卫生宣传教育,降低学龄儿童的患龋率。

关键词：仡佬族苗族学龄儿童龋病

2016年中国马铃薯生产成本收益分析及建议

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农业展望 2017年第5期13卷 44-47页

作者：刘洋高明杰张萌罗其友马力阳杨亚东中国农业科学院农业资源与农业区划研究所北京100081

2016年由于局部地区旱灾和病害发生较为严重,中国的马铃薯单产略减、总产量下降,形成价格上涨预期,薯农惜售,马铃薯加工量减少、库存增加。2016年马铃薯生产成本有所增加,同比增长7.39%。由于马铃薯售价总体上涨,生产收益也有较大增长,... 详细信息

2016年由于局部地区旱灾和病害发生较为严重,中国的马铃薯单产略减、总产量下降,形成价格上涨预期,薯农惜售,马铃薯加工量减少、库存增加。2016年马铃薯生产成本有所增加,同比增长7.39%。由于马铃薯售价总体上涨,生产收益也有较大增长,同比增幅达39.63%,高于成本增幅。未来,可通过完善信息监测发布体系、积极推进马铃薯田间作业机械化、加快马铃薯加工配套体系建设等促进马铃薯生产节本增效及市场稳定。

关键词：马铃薯生产成本收益分析产量价格贸易

Estimation of biophysical properties of cell exposed to electric field

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Chinese Physics B 2021年第3期30卷 546-554页

作者： Hui Zhang liyang Wang Peijie Zhang Xiaodi Zhang Jun ma College of Physics&Electronic Engineering Xianyang Normal UniversityXianyang 712000China College of Life Science Shaanxi Normal UniversityXi’an 710062China School of Highway Chang’an UniversityXi’an 710064China Department of Physics Lanzhou University of TechnologyLanzhou 730050China

Excitable media,such as cells,can be polarized and magnetized in the presence of an external electromagnetic *** fact,distinct geometric deformation can be induced by the external electromagnetic field,and also the capacitance of the membrane of cell can be changed to pump the field ***,the distribution of ion concentration inside and outside the cell can also be greatly *** on the theory of bio-electromagnetism,the distribution of field energy and intracellular and extracellular ion concentrations in a single shell cell can be estimated in the case with or without external electric ***,the dependence of shape of cell on the applied electronic field is *** the viewpoint of physics,the involvement of external electric field will change the gradient distribution of field energy blocked by the *** the intracellular and extracellular ion concentration show a certain difference in generating timevarying membrane potential in the presence of electric *** a constant electric field is applied to the cell,distinct geometric deformation is induced,and the cell triggers a transition from prolate to spherical and then to oblate ellipsoid *** is found that the critical frequency in the applied electric field for triggering the distinct transition from prolate to oblate ellipsoid shape obtains smaller value when larger dielectric constant of the cell membrane and intracellular medium,and smaller conductivity for the intracellular medium are ***,the effect of cell deformation is estimated by analyzing the capacitance per unit area,the density of field energy,and the change of ion concentration on one side of cell *** intensity of external applied electric field is further increased to detect the change of ion *** the biophysical effect in the cell is *** the deformation effect of cells in electric field should be considered when regulating and preventing harm to norm

关键词： neuron field energy membrane deformation ion concentration

Total ionizing radiation effects of 2-T SONOS for 130 nm/4 Mb NOR flash memory technology

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Science China(Information Sciences) 2014年第6期57卷 173-181页

作者： QIAO FengYing PAN liyang YU Xiao ma HaoZhi WU Dong XU Jun Institute of Microelectronics Tsinghua University Tsinghua National Laboratory for Information Science and Technology

In this paper,we have studied the total ionizing dose(TID)radiation response up to 2 Mrad(Si)of silicon-oxide-nitride-oxide-silicon(SONOS)memory cells and memory circuits,fabricated in a 130 nm complimentary metal-oxide-semiconductor(CMOS)SONOS *** explored the threshold voltage(VT)degradation mechanism and found that the VT shifts of SONOS cells depend on the charge state;simply programming the cell to a higher VT cannot compensate for the radiation induced VT *** off-state current(Ioff)increase in the SONOS cell is also studied in this *** VT and Ioffdegradation would affect the memory *** data failures are mainly caused by VT shifts under irradiation,and program and erase failures are mainly caused by increased Ioff,which overloads the charge pumping *** varying the reference current,our 4 Mb NOR flash chip has the potential to survive a radiation dose of 1 Mrad(Si)in read mode.

关键词： silicon-oxide-nitride-oxide-silicon SONOS total ionizing dose TID flash memory radiation effects 130 nm

Metabolic utilization of intravenously injected iron from different iron sources in target tissues of broiler chickens

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Animal Nutrition 2022年第2期9卷 74-83页

作者： Lin Lu Xueyu Dong Xuelian ma liyang Zhang Sufen Li Xugang Luo Xiudong Liao Mineral Nutrition Research Division State Key Laboratory of Animal NutritionInstitute of Animal ScienceChinese Academy of Agricultural SciencesBeijing100193China Poultry Mineral Nutrition Laboratory College of Animal Science and TechnologyYangzhou UniversityYangzhou225000China Department of Animal Science Hebei Normal University of Science and TechnologyQinhuangdao066004China

No information is available regarding the utilization of iron (Fe) from different Fe sources at a targettissue level. To detect differences in Fe metabolic utilization among Fe sources, the effect of intravenouslyinjected Fe on growth performance, hematological indices, tissue Fe concentrations and Fe-containingenzyme activities and gene expressions of Fe-containing enzymes or protein in broilers was *** d 22 post-hatching, a total of 432 male chickens were randomly allotted to 1 of 9 treatments ina completely randomized design. Chickens were injected with either a 0.9% (wt/vol) NaCl solution(control) or a 0.9% NaCl solution supplemented with Fe sulphate or 1 of 3 organic Fe sources. The 3organic Fe sources were Fe chelates with weak (Fe-MetW), moderate (Fe-ProtM) or extremely strong (Fe-ProtES) chelation strength. The 2 Fe dosages were calculated according to the Fe absorbabilities of 10%and 20% every 2 d for a duration of 20 d. Iron injection did not affect (P > 0.05) ADFI, ADG or FCR duringeither 1 to 10 d or 11 to 20 d after injections. Hematocrit and Fe concentrations in the liver and kidney ond 10 after Fe injections, and Fe concentrations in the liver or pancreas and ferritin heavy-chain (FTH1)protein expression level in the liver or spleen on d 20 after Fe injections increased (P≤0.05) as injectedFe dosages increased. When the injected Fe level was high at 20% Fe absorbability, the chickens injectedwith Fe-ProtES had lower (P < 0.001) liver or kidney Fe concentrations and spleen FTH1 protein levelsthan those injected with Fe-MetW or Fe-ProtM on d 20 after injections. And they had lower (P < 0.05)liver cytochrome C oxidase mRNA levels on d 20 after injections than those injected with Fe-MetW or Fesulphate. The results from this study indicate that intravenously injected Fe from Fe-ProtES was the least utilizable and functioned in the sensitive target tissue less effectively than Fe from Fe sulfate, Fe-MetW or Fe-ProtM.

关键词： Intravenous injection Iron-containing protein Gene expression Iron source Broiler

腹泻奶牛源大肠杆菌的分离鉴定及中药的体外抑菌效果

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畜牧与兽医 2024年第2期56卷 116-123页

作者：吴道义马金萍王明进王霞曾继晶周礼扬罗耀李坤毕节市畜牧兽医科学研究所贵州毕节551799 南京农业大学动物医学院江苏南京210095

为了研究贵州毕节某奶牛场荷斯坦奶牛发生腹泻的原因,从该奶牛场采集50份新鲜粪便样本,通过平板划线法对大肠杆菌进行分离纯化和PCR鉴定,采用K-B纸片法进行药物敏感试验,并对多种耐药基因进行PCR检测。针对多重耐药菌,选取虎耳草和杜鹃... 详细信息

为了研究贵州毕节某奶牛场荷斯坦奶牛发生腹泻的原因,从该奶牛场采集50份新鲜粪便样本,通过平板划线法对大肠杆菌进行分离纯化和PCR鉴定,采用K-B纸片法进行药物敏感试验,并对多种耐药基因进行PCR检测。针对多重耐药菌,选取虎耳草和杜鹃花2种中草药进行体外抑菌效果研究。结果显示:从腹泻奶牛粪便中分离出31株细菌,其菌落形态和生化特性与大肠杆菌相符;16S rRNA基因测序比对发现该牛场分离的菌株与NCBI数据库中大肠杆菌参考菌株的同源性达到99.65%~99.86%,确定该奶牛场的腹泻病原为大肠杆菌;药敏试验发现该牛场来源的大肠杆菌对多种抗生素(强力霉素、红霉素、青霉素G和四环素)耐药,而对磺胺异恶唑、头孢曲松、环丙沙星、庆大霉素、多黏菌素B、磷霉素等10种抗生素敏感;PCR扩增相关耐药基因发现,导致该牛场腹泻的大肠杆菌携带2种β-内酰胺类(blaCTX-M、blaTEM),4种四环素类(TetD、TetB、TetK、TetD、TetA),2种氨基糖苷类(ant(3″)-Ia、rmtB)和3种喹诺酮类(qnrS、qepA、oqxA)耐药基因。体外抑菌研究发现,杜鹃花(3.125 mg/mL)的水提物有显著的抑菌效果。试验结果可为该奶牛场防治大肠杆菌性腹泻提供用药指导,同时为开发替抗中草药产品提供了依据。

关键词：腹泻大肠杆菌分离鉴定耐药性耐药基因

兰州地区汉族老年人少肌症与少肌性肥胖流行病学调查

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解剖学杂志 2019年第4期42卷 393-397页

作者：谢文清马斌马力扬何进全白静雅欧阳思维莫晓丹何烨海向军西北民族大学少数民族体质与健康重点实验室

目的:应用生物电阻抗法(BIA)对兰州地区60岁及以上汉族老年人少肌症与少肌性肥胖的患病率进行调查.方法:对2472位20岁以上的兰州汉族成人进行BIA检测,获得兰州地区汉族成人各年龄段肌肉量与脂肪量的分布情况.其中801位(20≤年龄<40)健... 详细信息

目的:应用生物电阻抗法(BIA)对兰州地区60岁及以上汉族老年人少肌症与少肌性肥胖的患病率进行调查.方法:对2472位20岁以上的兰州汉族成人进行BIA检测,获得兰州地区汉族成人各年龄段肌肉量与脂肪量的分布情况.其中801位(20≤年龄<40)健康年轻人(男、女为273、528)作为青年对照组,获得少肌症与少肌性肥胖的诊断切点;663位(年龄≥60)老年人(男、女为298、365)作为老年组,获得老年人少肌症与少肌性肥胖的患病率.结果:兰州汉族成人人体质量、全身及躯干肌肉量、四肢肌肉量都呈现随年龄的增长先增加后下降的变化,且存在性别差异;全身、躯干、四肢脂肪量大致都呈现出上升而后稳定在较高水平的趋势.兰州地区老年人男性和女性少肌症诊断切点为ASM/height2分别为≤6.83 kg/m^2和≤5.65 kg/m^2.兰州地区老年人男性和女性肥胖的体脂率切点分别为≥24.79%和≥36.61%.兰州地区老年人少肌症的患病率为13.73%,其中男性患病率为12.42%,女性患病率14.79%,同性别间≥70年龄组患病率高于60~年龄组,差异有统计学意义.兰州地区老年人少肌性肥胖的患病率为1.51%,男性和女性差异无统计学意义.结论:兰州地区汉族老年人少肌症和少肌性肥胖的患病率均较低,且存在年龄差异.

关键词：生物电阻抗法老年人少肌症肥胖少肌性肥胖