检索结果-南通市图书馆

Preparation of silver tin oxide powders by hydrothermal reduction and crystallization

在线全文

学校读者我要写书评

暂无评论

Rare metals 2007年第5期26卷 470-475页

作者： DU Zuojuan YANG Tianzu GU Yingying QIU Xiaoyong dou Aichun School of metallurgy Science and Engineering Central South University Changsha 410083 China School of Chemistry and Chemical Engineering Central South University Changsha 410083 China

Silver tin oxide composite powders were synthesized by the hydrothermal method with a silver ammine solution and a Na2SnO3 solution as raw materials. H2C2O4 was used as the co-precipitator of silver ions and tin ions. The co-precipitation conditions were investigated. The results show that the co-precipitate of Ag2C2O4 and Sn（OH）4 is available when the pH value of the solution is 4.27-8.36. Using the obtained precipitate as precursor,the reduction of Ag＋ and the crystallization of tin oxide were carried out simultaneously by the hydrothermal method and silver tin oxide composite powders were obtained. The composite powders were characterized by X-ray diffraction （XRD） analysis,scanning electron microscope （SEm）,and energy spectrum analysis. The results show that the silver tin oxide composite powders are small with a diameter of about 2 μm and with homogeneous distribution of tin.

关键词： composite material silver tin oxide hydrothermal method co-precipitation

在线全文

学校读者我要写书评

暂无评论

搅拌摩擦沉积增材2219铝合金组织及性能

航空材料学报 2024年第1期44卷 152-162页

作者：王瑞林杨新岐唐文珅罗庭赵耀邦窦恩惠天津大学材料科学与工程学院天津300354 上海航天精密机械研究所上海201600

在主轴转速250~350 r/min、横向移动速度50~150 mm/min工艺参数下进行2219-T87铝合金搅拌摩擦沉积增材(additive friction stir deposition,AFSD)实验,探究工艺参数与多层热循环对沉积层宏观成形、微观组织和力学性能的影响。结果表明:... 详细信息

在主轴转速250~350 r/min、横向移动速度50~150 mm/min工艺参数下进行2219-T87铝合金搅拌摩擦沉积增材(additive friction stir deposition,AFSD)实验,探究工艺参数与多层热循环对沉积层宏观成形、微观组织和力学性能的影响。结果表明:在主轴转速250 r/min,移动速度100 mm/min工艺参数下可获得成形良好的单道16层增材试样。增材区晶粒尺寸发生显著细化,在4~6μm之间,细小等轴晶组织取代沉积棒料粗大的无规则晶粒组织。增材试样发生剧烈的动态再结晶,整体再结晶晶粒在80%以上,试样底部(第1层)受到多次热循环影响,再结晶晶粒达到91.8%。增材区域织构基本由Cube、Copper、P和RtB四种再结晶织构以及S、T和Brass织构构成。增材试样的硬度和抗拉强度相比于沉积棒料都明显降低,其中,第16层沉积层硬度最大为80HV,约为沉积棒料母材的55.6%;第1~8层沉积层硬度均匀在60HV。增材区水平(longitudinal direction,LD)方向第9~16层和1~8层的平均抗拉强度分别为243.0 mPa和219.3 mPa,约为母材的60.0%和52.9%;平均伸长率为19.4%和24.5%,分别约为母材的181.1%和229.0%。增材试样LD方向断裂模式均为韧性断裂。

关键词：搅拌摩擦沉积增材 2219-T87铝合金微观组织力学性能

Effect of bio-surfactant on municipal solid waste composting process

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2005年第3期17卷 409-413页

作者： XIBei-dou LIUHong-liang HUANGGH ZHANGBai-yu QINXiao-sheng ChineseResearchAcademyofEnvironmentalSciences Beijing100012China EVSE-FacultyofEngineering UniversityofReginaReginaSask.S4S0A2Canada 不详

Bio-surfactant is a new type of surfactant that is produced in microbial metabolism. Adding bio-surfactant during composting process, especially to those contain some toxic substances, has been proved to be a promising way. In this study, Strains Ⅲ(2), a bacterial with high activity to produce bio-surfactant, were isolated firstly. Following comparison experiments with and without adding Strains Ⅲ(2), namely Run 1 and Run R, were conducted, respectively. The experimental results showed that, by adding Strains Ⅲ(2), the surface tension could reduce from 46.5 mN/m to 39.8 mN/m and the corresponding time to maintain the surface tension under 50 mN/m could prolong from 60 h to 90 h. The oxygen uptake rate and total accumulated oxygen consumption with Stains Ⅲ(2) were both higher than those without Strains Ⅲ(2), while the accumulation of H_2S in outlet gas was reduced to around 50% of Run R. moreover, two additional experiments were also carried out to examine the effects of strains coming from different systems. One is adding Strains Ⅲ(2) with a dose of 0.4%(Run 2), and the other is seedling commercial Strains at the same conditions, the composting experiments showed that: Run 2 was more effective than Run 3, because the commercial Strains can be suppressed significantly in a complex composting system with different pH, high temperature and some of metals. The bio-surfactant was also added into the solid waste, which contained some toxic substances, the corresponding results showed that the remove rate of Hg and sodium pentachlorophenolate(PCP-Na) could be improved highly. Thus, the microenvironment, reactionrate and composting quality could be enhanced effectively by adding bio-surfactant to the composting process.

关键词： municipal solid waste composting bio-surfactant composting quality

基于UAV-Sfm方法的黄土高原砒砂岩区侵蚀监测算法比较

在线全文

学校读者我要写书评

暂无评论

水土保持学报 2024年第3期38卷 91-100页

作者：刘益麟李朋飞李豆胡晋飞白晓严露丹杨西安科技大学测绘科学与技术学院西安710054

[目的]为比较地形变化监测算法在黄土高原砒砂岩区的适用性。[方法]以皇甫川流域特拉沟一支沟为研究对象,采用无人机摄影测量技术获取2022年7月至2023年3月影像,结合Sfm技术生成三维点云数据,比较分析[digital elevation model of diffe... 详细信息

[目的]为比较地形变化监测算法在黄土高原砒砂岩区的适用性。[方法]以皇甫川流域特拉沟一支沟为研究对象,采用无人机摄影测量技术获取2022年7月至2023年3月影像,结合Sfm技术生成三维点云数据,比较分析[digital elevation model of difference(DoD)、cloud to cloud(C2C)、cloud to mesh(C2m)、multiscale model to model cloud comparison(m3C2)]等4种算法的侵蚀产沙监测精度,并分析点云密度变化对各方法精度的影响。[结果](1)4种常用算法在空间上都能监测到大幅度地表变化。其中,以m3C2算法的结果最优,线性拟合结果最好(R^(2)=0.953,pmAE=0.0161 m,mRE=3.37%,RmSE=0.0194 m),C2m算法其次,DoD算法再次,而C2C算法结果最差。(2)通过比较,DoD算法仅适用于平坦区域的快速检测,坡度陡峭的区域监测侵蚀沉积量存在高估的现象。(3)m3C2和C2C算法对点云密度变化敏感,而C2m和DoD受点云密度变化影响较小。[结论]研究结果可为黄土高原砒砂岩地区基于UAV-Sfm的侵蚀产沙监测方法的选择提供参考。

关键词： Sfm 地形变化监测算法点云密度侵蚀监测黄土高原砒砂岩地区

Research and Implementation of Credit Investigation Sharing Platform Based on double Blockchain

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Computers, materials & Continua 2023年第6期75卷 5193-5211页

作者： Han Yanyan Wei Wanqi dou Kaili Li Peng College of Information Engineering Xidian UniversityXi’an710071China Department of Electronic and Communication Engineering Beijing Electronic Science and Technology InstituteBeijing100070China Department of Cyberspace Security Beijing Electronic Science and Technology InstituteBeijing100070China

As the development of the modern economy is increasingly insep-arable from credit support,the traditional credit investigation mode has yet to meet this *** of the difficulties in conventional credit data sharing among credit investigation agencies,poor data portability,and centralized supervision,this paper proposes a data-sharing scheme for credit investigation agencies based on a double *** the problems such as difficult data sharing,difficult recovery of damaged data,and accessible data leakage between institutions and users with non-traditional credit inves-tigation data other than credit,this paper proposes a data-sharing scheme for credit investigation subjects based on the digital *** on the above two solutions,this paper designs a double blockchain credit data-sharing plat-form based on the“public chain+alliance chain”from credit investigation agencies’and visiting subjects’*** sharing platform uses the alliance chain as the management chain to solve the problem of complex data sharing between credit bureaus and centralized supervision,uses the public chain as the use chain to solve the problem of complex data sharing between the access subject and the credit bureaus,uses the interplanetary file system and digital envelope and other technologies to solve the problem of difficult recovery of damaged data,data leakage,and other *** the upload test,the average upload speed reaches 80.6 m/*** average download speed of the system is 88.7 m/s after the download *** multi-thread stress test tests the linkage port on the system package,and the average response time for the hypertext transfer protocol(HTTP)is 0.6 *** system performance and security analysis show that the sharing platform can provide safe and reliable credit-sharing services for organizations and users and high working efficiency.

关键词： Dual blockchain credit data sharing truffle framework digital envelope ipfs

儿童重症监护病房血流感染严重脓毒症的病原学特点及死亡的影响因素分析

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中华医学杂志 2024年第3期104卷 198-204页

作者：窦家莹周益平崔云孙汀史婧奕熊熙张育才上海市儿童医院上海交通大学医学院附属儿童医院重症医学科，上海200062

目的总结儿童重症监护病房(PICU)血流感染(BSI)严重脓毒症的病原学特点,分析死亡的影响因素。方法回顾性选择2016年1月至2021年12月上海交通大学医学院附属儿童医院PICU收治的BSI严重脓毒症患儿,根据患儿出院转归情况分为存活组和死亡... 详细信息

目的总结儿童重症监护病房(PICU)血流感染(BSI)严重脓毒症的病原学特点,分析死亡的影响因素。方法回顾性选择2016年1月至2021年12月上海交通大学医学院附属儿童医院PICU收治的BSI严重脓毒症患儿,根据患儿出院转归情况分为存活组和死亡组。收集患儿的临床资料、实验室指标以及病原菌特点与耐药情况。总结病原菌、临床与实验室指标特征,基于二元多因素logistic回归分析BSI严重脓毒症患儿死亡的影响因素。结果共纳入BSI严重脓毒症患儿132例,男81例,女51例,年龄[m(Q_(1),Q_(3))]为36(10,119)个月,其中死亡组38例[男23例,女15例,年龄36(15,120)个月],存活组94例[男58例,女36例,年龄36(8,108)个月]。共分离出病原菌132株,革兰阴性菌87株(65.9%),占比前5位的病原菌依次为肺炎克雷伯菌24例(18.2%)、大肠埃希菌17例(12.9%)、鲍曼不动杆菌13例(9.8%)、铜绿假单胞菌10例(7.6%)、金黄色葡萄球菌10例(7.6%)。医院内获得性BSI多重耐药菌比例高于社区获得性BSI[52.9%(36/68)比15.6%(10/64),P=0.001]。存活组与死亡组患儿中社区获得性感染率分别为58.5%(55/94)和23.7%(9/38),差异有统计学意义(P<0.001)。死亡组患儿发生BSI前中心静脉导管置入比例高于存活组[63.2%(24/38)比42.6%(40/94),P=0.034]。二元多因素logistic回归分析显示,医院内获得性感染(OR=4.80,95%CI:1.825~12.621,P=0.001)、中性粒细胞绝对值(ANC)(OR=0.93,95%CI:0.863~0.993,P=0.030)和白蛋白降低(OR=0.89,95%CI:0.817~0.977,P=0.014)是死亡的危险因素。结论BSI严重脓毒症的主要病原菌为革兰阴性菌,医院内获得BSI多重耐药菌比例高;医院内获得性感染、ANC和白蛋白降低的BSI严重脓毒症患儿死亡风险高。

关键词：脓毒症血流感染危险因素重症监护病房儿童

The structure,tensile properties and water resistance of hydrolyzed feather keratin-based bioplastics

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2016年第3期24卷 415-420页

作者： Yao dou Buning Zhang ming He Guoqiang Yin Yingde Cui School of materials Science and Engineering Northwestern Polytechnical UniversityXi'an 710072China Green Chemical Engineering Institute Zhongkai University of Agriculture and EngineeringGuangzhou 510225China Guangzhou Vocational College of Science and Technology Cuangzhou 510550China

Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide. The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process. The thermal analysis showed that high temperature and high pres- sure improved the compatibility between the glycerol and the HFI（ molecules. Also it was shown that the addi- tion of water is necessary in the hot-pressing process of films, The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol. By increasing the glycerol content, the film tensile strength （orb ） decreases from 10,5 mPa to 5.7 mPa and the solubility increases from 15.3% to 20.9%, while the elongation at break （εb） achieves the maximum value of 63,8% for the film with 35% glycerol. The swelling was just below 16.9% at 25 ℃ for 24 h, suggesting a good stability of the films in water. The water vapor permeability （WVP） varied between 3.02 x 10 ^10g. m 2. s-1 . pa-1 and 4.11 x 10-10g · m-2 · s-1 · Pa-1 for the films with 20%and 40% glycerol, respectively. The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.

关键词： Feather keratin Biodegradable films Glycerol Hot-pressing Eco-ffiendly material

基于mAX-DOAS观测的鹤山地区对流层甲醛廓线反演研究

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2024年第6期44卷 1781-1788页

作者：钱园园罗宇涵周海金窦科常振杨太平奚亮汤付颖徐自强司福祺中国科学院合肥物质科学研究院安徽光学精密机械研究所环境光学与技术重点实验室安徽合肥230031 中国科学技术大学安徽合肥230026

甲醛(HCHO)是大气中一种十分重要的痕量气体,它不仅与人类健康和环境密切相关,还在对流层光化学反应中扮演着极其重要的角色。近年来,我国珠三角地区的秋季对流层臭氧及甲醛污染问题较为严重,而对流层甲醛也是分析边界层臭氧形成机理的... 详细信息

甲醛(HCHO)是大气中一种十分重要的痕量气体,它不仅与人类健康和环境密切相关,还在对流层光化学反应中扮演着极其重要的角色。近年来,我国珠三角地区的秋季对流层臭氧及甲醛污染问题较为严重,而对流层甲醛也是分析边界层臭氧形成机理的关键性指标之一,因此,在珠三角地区开展甲醛观测实验具有十分重要的意义。利用多轴差分吸收光谱技术(mAX-DOAS)反演了鹤山超级站2019年9月20日至10月3日期间的氧气二聚体(O_(4))与HCHO的差分斜柱浓度(DSCD),使用几何近似法得到了甲醛的大气质量因子(AmF),进而获得了对流层甲醛的垂直柱浓度(VCD)。结果显示,观测期间的对流层甲醛VCD在4.99×10^(13)~6.48×10^(16)molec·cm^(-2)之间波动,平均值为2.18×10^(16)molec·cm^(-2)。将mAX-DOAS反演的对流层甲醛VCD与TROPOmI结果进行了对比,结果表明,mAX-DOAS与TROPOmI结果近乎一致,相关性系数R为0.80,但9月25日与28日的TROPOmI结果偏低了约25%,这可能是由于观测方式不同所导致的。此外,该研究还基于反演的O_(4)与甲醛DSCD,使用基于最优估计算法的海德堡大学廓线反演算法(HEIPRO)反演了观测期间的对流层气溶胶及甲醛廓线,结果表明,甲醛污染主要集中在近地面0~800 m内,观测期间的甲醛污染主要来源于当地的工业及机动车尾气排放。将mAX-DOAS技术反演的近地面甲醛结果与2,4-二硝基苯肼色谱技术测量结果进行了对比,结果表明,两种技术的近地面甲醛结果的一致性较高,均观测到了9月27至29日的近地面甲醛高值(峰值达到了14.31μg·m^(-3)),且相关性系数R为0.88,斜率为0.98,验证了mAX-DOAS技术反演的近地面甲醛结果的可靠性。mAX-DOAS技术可实现对流层甲醛VCD的实时监测,可作为验证星载观测结果的一种重要手段,结合最优估计算法,mAX-DOAS技术还可以实现对流层甲醛廓线的反演。

关键词：多轴差分吸收光谱技术对流层甲醛最优估计算法鹤山卫星校验

Perineal rectosigmoidectomy for strangled rectal prolapse:A case report

在线全文

学校读者我要写书评

暂无评论

Case Reports in Clinical medicine 2014年第1期3卷 64-66页

作者： Alpha Oumar toure Cheikh Tidiane Diop Fode Baba toure Thomas marcel m.Wade Gabriel Ngom Department of General Surgery Regional Hospital of OurossoguiOurossoguiSenegal Department of Pediatric Surgery Aristide Le Dantec HospitalDakarSenegal

Strangled rectal prolapse, the rare disease, is a proctological emergency. Its management is controversial. When it is not reducible and signs of ischemia are present, the Altemeierperineal rectosigmoidectomy remains the best treatment. This study aimed to report our experience on the management of strangled rectal prolapse about 1 case in a 45-year-old man, a holder of a rectal prolapse for 2 years. On admission, he had strangled prolapse for 24 hours with edema. After a vain attempt of manual reduction and installation of necrosis after 48 hours, he had an Altemeier rectosigmo?dectomy. The postoperative course was uneventful and the patient was discharged on the 6th postoperative day. The results were very good, after one year follow-up.

关键词： Strangled Rectal Prolapsed Altemeier Rectosigmoidectomy