期刊文献+
共找到24,886篇文章
< 1 2 250 >
每页显示 20 50 100
Mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel 预览
1
作者 Shaosen Ma Weizhong Chen Wusheng Zhao 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期159-171,共13页
Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels.This study aims to investigate the mechanical properties and associated seismic isolation effects of fo... Foamed concrete has a good energy absorption capability and can be used as seismic isolation material for tunnels.This study aims to investigate the mechanical properties and associated seismic isolation effects of foamed concrete layer in rock tunnel.For this,a series of uniaxial/triaxial compression tests was conducted to understand the effects of concrete density,confining stress and strain rate on the mechanical properties of foamed concrete.The direct shear tests were also performed to investigate the effects of concrete density and normal stress on the nonlinear behaviors of foamed concrete layer-lining interface.The test results showed that the mechanical properties of foamed concrete are significantly influenced by the concrete density.The foamed concrete also has high volumetric compressibility and strain-rate dependence.The peak stress,residual stress,shear stiffness and residual friction coefficient of the foamed concrete layer-lining interface are influenced by the foamed concrete density and normal stress applied.Then,a crushable foam constitutive model was constructed using ABAQUS software and a composite exponential model was also established to study the relationship between shear stress and shear displacement of the interface,in which their parameters were fitted based on the experimental results.Finally,a parametric analysis using the finite element method(FEM)was conducted to understand the influence of foamed concrete layer properties on the seismic isolation effect,including the density and thickness of the layer as well as the shear stiffness and residual friction coefficient of the interface.It was revealed that lower density and greater thickness in addition to smaller shear stiffness or residual friction coefficient of the foamed concrete layer could yield better seismic isolation effect,and the influences of the first two tend to be more significant. 展开更多
关键词 ROCK TUNNEL Foamed concrete SEISMIC ISOLATION LAYER SEISMIC ISOLATION mechanism
在线阅读 下载PDF
Application of a 3D-printed “fistula stent” in plugging enteroatmospheric fistula with open abdomen: A case report 预览
2
作者 Zi-Yan Xu Hua-Jian Ren +2 位作者 Jin-Jian Huang Zong-An Li Jian-An Ren 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第14期1775-1782,共8页
BACKGROUND Open abdomen (OA) has been generally accepted for its magnificent superiority and effectiveness in patients with severe trauma, severe intra-abdominal infection, and abdominal compartment syndrome. In the m... BACKGROUND Open abdomen (OA) has been generally accepted for its magnificent superiority and effectiveness in patients with severe trauma, severe intra-abdominal infection, and abdominal compartment syndrome. In the meantime, OA calls for a mass of nursing and the subsequent enteroatomospheric fistula (EAF), which is one of the most common complications of OA therapy, remains a thorny challenge. CASE SUMMARY Our team applied thermoplastic polyurethane as a befitting material for producing a 3D-printed “fistula stent” in the management of an EAF patient, who was initially admitted to local hospital because of abdominal pain and distension and diagnosed with bowel obstruction. After a series of operations and OA therapy, the patient developed an EAF. CONCLUSION Application of this novel “fistula stent” resulted in a drastic reduction in the amount of lost enteric effluent and greatly accelerated rehabilitation processes. 展开更多
关键词 3D PRINTING Enteroatmospheric FISTULA Open ABDOMEN ISOLATION technique Case report
在线阅读 免费下载
壮药珠芽艾麻化学成分研究
3
作者 王宇萌 温海成 窦德强 《中国药学杂志》 CAS CSCD 北大核心 2019年第10期773-776,共4页
目的研究壮药珠芽艾麻(Laportea bulbifera)的化学成分。方法珠芽艾麻用体积分数60%乙醇提取,经硅胶、聚酰胺、Sephadex LH-20、ODS、重结晶、半制备HPLC进行分离纯化。结合理化性质、波谱数据鉴定化合物的结构。结果从中分离出10个化合... 目的研究壮药珠芽艾麻(Laportea bulbifera)的化学成分。方法珠芽艾麻用体积分数60%乙醇提取,经硅胶、聚酰胺、Sephadex LH-20、ODS、重结晶、半制备HPLC进行分离纯化。结合理化性质、波谱数据鉴定化合物的结构。结果从中分离出10个化合物,分别鉴定为β-谷甾醇(1),原儿茶酸乙酯(2),东莨菪亭(3),反式肉桂酸(4),(E)-对羟基肉桂酸(5),山柰酚-7-O-α-L-鼠李糖苷(6),木犀草素(7),没食子酸乙酯(8),(+)-异落叶松脂素-9-O-β-D吡喃葡萄糖(9)和山柰酚-3,7-α-L-二鼠李糖苷(10)。结论化合物2,5,7~9为首次从艾麻属植物中分离得到,化合物2~5,7~9为首次从该植物中分离得到。 展开更多
关键词 壮药 珠芽艾麻 化学成分 分离 鉴定
茶园土壤中优势菌株毛霉菌的分离、纯化及鉴定 预览
4
作者 周小露 刘丽明 +4 位作者 宋加艳 宋丽莎 田茂燕 王利荣 周才碧 《山西农业科学》 2019年第2期156-158,179共4页
通过对黔南州茶园中优质土壤进行稀释、培养,分离、纯化得到一株优势菌株,利用形态学和分子生物学方法鉴定该优势菌为毛霉菌。毛霉菌对农业秸秆的腐化和土壤有机物的分解有很大的作用,可以促进茶树的生长发育,有利于茶园生物有机肥的研发。
关键词 茶园土壤 毛霉菌 分离 纯化 鉴定
在线阅读 下载PDF
陇西腊肉加工过程中优势乳酸菌的分离及其发酵性能研究 预览
5
作者 邓展瑞 贠建民 +2 位作者 郭娟 牛耀星 李彦虎 《生物技术进展》 2019年第2期200-209,共10页
陇西腊肉是一种传统发酵风味肉制品。以陇西腊肉为材料,通过经典形态学分类和生理生化鉴定,对其加工过程中的优势乳酸菌(lactic acid bacteria,LAB)进行分离、鉴定。通过测定菌株的产酸能力、生长特性、耐氯化钠和亚硝酸钠能力以及产气... 陇西腊肉是一种传统发酵风味肉制品。以陇西腊肉为材料,通过经典形态学分类和生理生化鉴定,对其加工过程中的优势乳酸菌(lactic acid bacteria,LAB)进行分离、鉴定。通过测定菌株的产酸能力、生长特性、耐氯化钠和亚硝酸钠能力以及产气、产黏液、产蛋白酶和脂肪酶的能力等,筛选具有优良发酵性能的菌株。随后,开展人工接种优良菌株的模拟腊肉加工试验,分析其对腊肉感官品质的影响。结果表明,从陇西腊肉中筛选获得7株乳酸菌,根据菌种形态学分类,初步鉴定分别为植物乳杆菌(Lactobacillus plantarum)、米酒乳杆菌(L.sake)、乳酸乳球菌(Lactococcus lactis)、戊糖片球菌(Pediococcus pentosaceus)、肠膜明串珠菌(Leuconostoc mesenteroides)、食品乳杆菌(L.alimentarius)和弯曲乳杆菌(L.curvatus),其中,菌株R-1(植物乳杆菌)产酸能力强、生长速度快,对氯化钠和亚硝酸钠均具有较好的耐受性。经模拟腊肉发酵试验发现,添加菌株R-1后,陇西腊肉的风味得到了较大改善,表现出更好的感官可接受性。研究表明,植物乳杆菌R-1具有优良的发酵性能,可作为传统陇西腊肉工艺现代化改造的菌株来源。 展开更多
关键词 陇西腊肉 乳酸菌 分离 鉴定 发酵性能
在线阅读 下载PDF
Marine sponges of the genus Stelletta as promising drug sources: chemical and biological aspects
6
作者 Qihao Wu Bastien Nay +4 位作者 Min Yang Yeke Ni Hong Wang Ligong Yao Xuwen Li 《药学学报:英文版》 CSCD 2019年第2期237-257,共21页
Marine sponges of the genus Stelletta are well known as rich sources of diverse and complex biologically relevant natural products, including alkaloids, terpenoids, peptides, lipids, and steroids. Some of these metabo... Marine sponges of the genus Stelletta are well known as rich sources of diverse and complex biologically relevant natural products, including alkaloids, terpenoids, peptides, lipids, and steroids. Some of these metabolites, with novel structures and promising biological activities, have attracted a lot of attention from chemists seeking to perform their total synthesis in parallel to intensive biological studies towards new drug leads. In this review, we summarized the distribution of the chemically investigated Stelletta sponges, the isolation, synthesis and biological activities of their secondary metabolites, covering the literature from 1982 to early 2018. 展开更多
关键词 MARINE natural products Stelletta SPONGE Isolation Total synthesis BIOLOGICAL activity MARINE DRUG LEADS
Clinical and Epidemiological Evolution of Sheep Pox in Morocco 预览
7
作者 Sara Lafar Khalil Zro +4 位作者 Andy Haegeman Mounir Khayli Kris De Clercq Renaud Lancelot My Mustapha Ennaji 《农业科学与技术:A》 2019年第2期103-113,共11页
Sheep pox is an infectious viral disease that affects specifically sheep and it is caused by the Capripoxvirus genus.The clinical signs include fever,diarrhea,difficulty breathing,nodules,lung lesions and death.In Mor... Sheep pox is an infectious viral disease that affects specifically sheep and it is caused by the Capripoxvirus genus.The clinical signs include fever,diarrhea,difficulty breathing,nodules,lung lesions and death.In Morocco,the 2010 epidemic of sheep pox was characterized by the emergence of a nodular form of the disease.The local strain was isolated and the analysis of affected animals was positively confirmed by virus isolation and real-time polymerase chain reaction(RT-PCR).The epidemiological analysis of 911 data records showed that the virus is endemic in the country;an average of 350 cases per year with an epizootic evolution was observed in 2010.The incidence varies depending on provinces and the disease appears confined to the central and the eastern regions of the country where a very intensive sheep breeding activity is taking place.The statistical analysis showed that there is a positive correlation between the endemicity and the significant factor of the rural market(p=0.006).The annual average morbidity and mortality rates were 2.96%(1.26%to 4.32%)and 0.71%(0.41%to 0.94%),respectively.The clinical findings associated to the epidemiological data analysis confirmed the presence of sheep pox in its nodular form and suggest that new pathogenic strains may have been introduced from Mauritania.The purpose of this work was to provide a better description of the spatiotemporal evolution of sheep pox disease based on some epidemiological indicators and to put forward plausible hypotheses regarding the emergence of the virus in order to implement an adequate control strategy. 展开更多
关键词 SHEEP pox Capripoxvirus EPIDEMIOLOGY CLINICAL SIGNS virus ISOLATION RT-PCR
在线阅读 下载PDF
一种低浓度胰蛋白酶获得胰岛单细胞的方法 预览
8
作者 雷维琼 刘欣煜 +1 位作者 艾慧婷 林显光 《绿色科技》 2019年第10期264-265,267共3页
为研究新型糖尿病药物的作用机理提供具有良好生理活性的胰岛单细胞,提出了一种改良的急性分离胰岛单细胞的方法,以大鼠麻醉后,采用胶原酶V内外联合消化法,手动挑选胰岛后用0.005%的低浓度胰蛋白酶分离胰岛单细胞。结果表明:该方法分离... 为研究新型糖尿病药物的作用机理提供具有良好生理活性的胰岛单细胞,提出了一种改良的急性分离胰岛单细胞的方法,以大鼠麻醉后,采用胶原酶V内外联合消化法,手动挑选胰岛后用0.005%的低浓度胰蛋白酶分离胰岛单细胞。结果表明:该方法分离的胰岛单细胞具有良好活性,是一种有效的分离方法,同时也具有低成本的优点。 展开更多
关键词 胰岛单细胞 分离 低浓度 胰蛋白酶
在线阅读 下载PDF
年龄结构乙肝传染病模型及稳定性 预览
9
作者 刘纪轩 王改霞 李学志 《应用数学》 CSCD 北大核心 2019年第3期600-607,共8页
本文讨论一年龄结构乙肝传染病模型,得出基本再生数■的表达式,证明:当■<1时,无病平衡态局部渐近稳定且全局渐近稳定;当■> 1时,存在唯一的地方病平衡态,并给出地方病平衡态的局部渐近稳定性条件,这些条件对于控制疾病的传播具... 本文讨论一年龄结构乙肝传染病模型,得出基本再生数■的表达式,证明:当■<1时,无病平衡态局部渐近稳定且全局渐近稳定;当■> 1时,存在唯一的地方病平衡态,并给出地方病平衡态的局部渐近稳定性条件,这些条件对于控制疾病的传播具有重要的理论及实际意义. 展开更多
关键词 年龄结构 隔离 基本再生数
在线阅读 免费下载
Isolation, Identification and Drug Susceptibility Test of a Strain of Escherichia coli Causing Fox Pneumonia 预览
10
作者 Liu Zhiqiang Zhao Xiaocui +9 位作者 Luo Junfeng Yao Weiping Feng Ling Wu Tonglei Zhang Zhiqiang Bai Xue Fu Yanfang Gao Qingshan Jia Qinghui Shi Qiumei 《动物与饲料科学:英文版》 CAS 2019年第1期32-34,共3页
[Objective] The paper was to determine the pathogen causing fox pneumonia in a breeding factory in Changli County.[Method]Through autopsy, a dominant strain was isolated from the lung of dead foxes, which was then per... [Objective] The paper was to determine the pathogen causing fox pneumonia in a breeding factory in Changli County.[Method]Through autopsy, a dominant strain was isolated from the lung of dead foxes, which was then performed Gram staining, 16 S rRNA sequence analysis and biochemical identification.[Result] The strain was negative in Gram staining, and was identified as E. coli through 16 S rRNA sequence analysis and biochemical identification. Drug susceptibility test was conducted using 15 kinds of drug susceptibility papers. The E. coli was sensitive to florfenicol, enrofloxacin, ceftriaxone, norfloxacin;intermediately sensitive to amikacin, gentamicin;and strongly resistant to penicillin, ampicillin,cefradine, sulfamethoxazole, lincomycin, streptomycin and amoxicillin.[Conclusion] It is difficult to treat E. coli causing fox pneumonia with traditional antibiotics clinically. 展开更多
关键词 FOX PNEUMONIA ESCHERICHIA coli ISOLATION and IDENTIFICATION Drug susceptibility test
在线阅读 免费下载
尾菜青贮乳酸菌的分离筛选及其青贮菌剂制备 预览
11
作者 彭章普 王洁 +3 位作者 麻和平 张文齐 刘彩云 邵建宁 《中国饲料》 北大核心 2019年第1期36-41,共6页
从市售泡菜中分离筛选适合尾菜青贮的乳酸菌,筛选获得产酸能力强、青贮效果好的2株菌株,通过细菌形态学、API50CH试剂条检测,鉴定SD2为植物乳杆菌,SD4为发酵乳杆菌。对两株菌株在5L立瓶中分别进行培养,确定了各自的培养最适收获期和两... 从市售泡菜中分离筛选适合尾菜青贮的乳酸菌,筛选获得产酸能力强、青贮效果好的2株菌株,通过细菌形态学、API50CH试剂条检测,鉴定SD2为植物乳杆菌,SD4为发酵乳杆菌。对两株菌株在5L立瓶中分别进行培养,确定了各自的培养最适收获期和两株菌株配比,制备的尾菜青贮菌剂总活菌数大于1.0×10^9cfu/mL。 展开更多
关键词 尾菜 乳酸菌 分离 筛选 青贮菌剂
在线阅读 下载PDF
Isolation and Identification of Four Strains of Salmonella and Drug Susceptibility Test 预览
12
作者 Guo Rui Ding Jialin +8 位作者 Luo Junfeng Feng Ling Liu Zhiqiang Zhao Xiaocui Yao Weiping Gao Qingshan Fu Yanfang Su Shuoqing Shi Qiumei 《动物与饲料科学:英文版》 CAS 2019年第1期39-41,44共4页
In order to isolate and identify the pathogenic bacteria causing dead chickens in a chicken farm in Qinhuangdao area, the liver, heart and other organs of dead chickens suspected of salmonella disease were collected a... In order to isolate and identify the pathogenic bacteria causing dead chickens in a chicken farm in Qinhuangdao area, the liver, heart and other organs of dead chickens suspected of salmonella disease were collected aseptically, and streaked on SS agar medium and chromagar medium. Transparent colonies were observed on SS agar medium, and purple and transparent colonies on CAS medium. The isolate was conducted purification, staining microscopy, biochemical tests, and 16 S rRNA sequence analysis, and the results showed that four strains of the isolated bacte-ria were salmonella. The 16 S rRNA sequence analysis of four strains of salmonella showed that the isolates shared more than 99% homology. Drug susceptibility test was performed using paper method, and the results showed that most of the strains were resistant to tilmicosin, cefradine and sul-famethoxazole, but were sensitive to ceftriaxone. 展开更多
关键词 CHICKEN SALMONELLA ISOLATION and identification DRUG SUSCEPTIBILITY test
在线阅读 免费下载
百香果果浆内生细菌的分离鉴定及生长条件的研究 预览
13
作者 陈正培 吴婉莹 +4 位作者 张银 向煜 余启明 蔡锦源 熊建文 《中国酿造》 CAS 北大核心 2019年第8期46-49,共4页
为了解百香果果浆的内生细菌,该研究采用平板计数琼脂(PCA)培养基从百香果果浆中分离内生细菌,通过形态观察及分子生物学技术对其进行鉴定,并对其生长条件进行研究。结果表明,从百香果果浆中分离得到3株菌落形态单一、均呈浅黄色的内生... 为了解百香果果浆的内生细菌,该研究采用平板计数琼脂(PCA)培养基从百香果果浆中分离内生细菌,通过形态观察及分子生物学技术对其进行鉴定,并对其生长条件进行研究。结果表明,从百香果果浆中分离得到3株菌落形态单一、均呈浅黄色的内生细菌,分别编号为GJ2-5、GJ2-13、GJ2-19,均呈革兰氏阳性。3株内生细菌均为泛菌属(Pantoea),其中,菌株GJ2-5和GJ2-13均为分散泛菌(Pantoea dispersa),菌株GJ2-19为Pantoea eucrina。3株内生细菌的最适生长培养基均为LB液体培养基,最适生长pH值均为5.5,最适生长温度均为35℃,生长周期为迟滞期(0~6 h)、对数期(6~18 h)、平稳期(18~22 h)和衰亡期(22 h以后)。 展开更多
关键词 百香果 内生细菌 分离 鉴定 生长条件
在线阅读 下载PDF
5G试验网的频率干扰分析 预览
14
作者 龙杰华 冯业伟 《现代信息科技》 2019年第7期53-55,58共4页
产生无线干扰的原因是多种多样的,如不同运营商的网络配置不合理、发射机的数据设置、周围环境、小区重叠及电磁兼容等。当前全球多个国家已竞相展开5G网络技术开发,我国工业和信息化部于2018年12月正式发文,向中国电信、中国移动和中... 产生无线干扰的原因是多种多样的,如不同运营商的网络配置不合理、发射机的数据设置、周围环境、小区重叠及电磁兼容等。当前全球多个国家已竞相展开5G网络技术开发,我国工业和信息化部于2018年12月正式发文,向中国电信、中国移动和中国联通三家运营商发放了5G系统中低频段试验频率的使用许可。5G试验网建设应该充分考虑不同制式通信系统之间的天线隔离度和干扰协调,本文将针对5G试验网的频率干扰进行分析。 展开更多
关键词 无线干扰 隔离度 5G 卫星通信
在线阅读 下载PDF
一株鸡大肠杆菌的分离鉴定与耐药性研究 预览
15
作者 江林宜 《中国动物传染病学报》 CAS 北大核心 2019年第1期100-103,共4页
无菌采集病死鸡的肝脏、肾脏、脾脏、肺脏等组织,接种于麦康凯平板和普通琼脂,进行细菌分离与培养,并对分离菌进行生化试验和16s rDNA基因序列分析,同时用14种抗菌药物对分离菌株进行药敏试验。结果显示,分离菌在麦康凯平板上呈红色圆... 无菌采集病死鸡的肝脏、肾脏、脾脏、肺脏等组织,接种于麦康凯平板和普通琼脂,进行细菌分离与培养,并对分离菌进行生化试验和16s rDNA基因序列分析,同时用14种抗菌药物对分离菌株进行药敏试验。结果显示,分离菌在麦康凯平板上呈红色圆形菌落;镜检结果为革兰氏阴性杆菌;分离菌株能够发酵葡萄糖、棉籽糖、乳糖、木糖等糖类并产酸产气,鸟氨酸及赖氨酸试验阳性,苯丙氨酸脱氨酶及硫化氢阴性,符合大肠杆菌的生化特性;16s rDNA基因序列测定结果显示分离菌株为大肠杆菌;分离菌株对菌必治、美洛西林、恩诺沙星、诺氟沙星的敏感率较高,而对萘啶酸、青霉素等耐药。本研究为鸡大肠杆菌的诊断和防治提供了依据。 展开更多
关键词 大肠杆菌 耐药性 分离 鉴定
在线阅读 免费下载
Optimal selection of tests for fault detection and isolation in multi-operating mode system 预览
16
作者 LIU Yuanhong 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第2期425-434,共10页
The complex systems are often in the structure of multi-operating modes, and the components implementing system functions are different under different operation modes, which results in the problems that components of... The complex systems are often in the structure of multi-operating modes, and the components implementing system functions are different under different operation modes, which results in the problems that components often fail in different operating modes, faults can be only detected in specified operating modes, tests can be available in specified operating modes,and the cost and efficiency of detecting and isolating faults are different under different operating modes and isolation levels. Aiming at these problems, an optimal test selection method for fault detection and isolation in the multi-operating mode system is proposed by using the fault pair coding and rollout algorithm. Firstly,the faults in fault-test correlation matrices under different operating modes are combined to fault-pairs, which is used to construct the fault pair-test correlation matrices under different operating modes.Secondly, the final fault pair-test correlation matrix of the multioperating mode system is obtained by operating the fault pair-test correlation matrices under different operating modes. Based on the final fault pair-test correlation matrix, the necessary tests are selected by the rollout algorithm orderly. Finally, the effectiveness of the proposed method is verified by examples of the optimal test selection in the multi-operating mode system with faults isolated to different levels. The result shows that the proposed method can effectively mine the fault detection and isolation ability of tests and it is suitable for the optimal test selection of the multi-operating mode system with faults isolated to the replacement unit and specific fault. 展开更多
关键词 operating MODE test optimization FAULT PAIR CODING FAULT detection FAULT ISOLATION
在线阅读 下载PDF
巴戟天抗疲劳功效成分的研究 预览
17
作者 詹积 徐德平 《天然产物研究与开发》 CAS CSCD 北大核心 2019年第6期995-1000,共6页
为探究巴戟天抗疲劳功效及活性成分。实验采用乙醇回流提取,经大孔树脂、MCI、ODS柱层析分离,核磁共振鉴定结构。结果表明,巴戟天醇提物大孔树脂分离得10%乙醇洗脱物对小鼠运动抗疲劳作用效果最明显,再经MCI、ODS柱分离,得到四个化合物... 为探究巴戟天抗疲劳功效及活性成分。实验采用乙醇回流提取,经大孔树脂、MCI、ODS柱层析分离,核磁共振鉴定结构。结果表明,巴戟天醇提物大孔树脂分离得10%乙醇洗脱物对小鼠运动抗疲劳作用效果最明显,再经MCI、ODS柱分离,得到四个化合物单体,分别是耐斯糖(1)、4-羧基-7-羟基-8-羟甲基-3,6-环烯醚萜苷(2)、4-乙酰基-8-羟甲基-3,7-环烯醚萜苷(3)和4-羧基-7-羟基-8-羟甲基-10-乙酰基-3,6-环烯醚萜苷(4)。化合物2、3、4为首次从巴戟天中分离得到的环烯醚萜苷类化合物。 展开更多
关键词 巴戟天 抗疲劳 分离 鉴定
在线阅读 下载PDF
从《唱吧,暴尸鬼,唱吧》探析沃德笔下的孤独与危机 预览
18
作者 庞好农 《山东外语教学》 2019年第4期78-86,共9页
沃德在《唱吧,暴尸鬼,唱吧》里描写了美国南方的乡土人情、社会风貌和种族关系,剖析了人在种族主义环境里的焦虑和绝望,揭露了种族偏见的荒诞性。他对人际孤独的描写独辟蹊径,从少年疏离、父子不和以及兄弟姐妹阴阳相隔等角度探究了人... 沃德在《唱吧,暴尸鬼,唱吧》里描写了美国南方的乡土人情、社会风貌和种族关系,剖析了人在种族主义环境里的焦虑和绝望,揭露了种族偏见的荒诞性。他对人际孤独的描写独辟蹊径,从少年疏离、父子不和以及兄弟姐妹阴阳相隔等角度探究了人际孤独与亲情危机的内在关联。此外,作者还从抑制自我、心理失落和友情失真等方面展现了现代社会的心理孤独,探究了希冀背离和唯我情结所导致的情感危机,揭示了不良人格把他人逼入自我封闭空间的社会悲剧。最后,沃德从死亡思索、身份危机和真我追求等方面揭示了存在孤独问题,表达了对现代人命运既忧虑又悲悯的本真情怀。 展开更多
关键词 《唱吧 暴尸鬼 唱吧》 杰斯敏·沃德 孤独 危机
在线阅读 下载PDF
一株大麻脱胶菌株的分离鉴定及其产果胶酶发酵培养基的优化 预览
19
作者 徐鹏 王大红 +4 位作者 陈亚欣 王泽轩 王子旭 魏来红 刘高 《中国麻业科学》 2019年第3期122-129,共8页
为了分离和鉴定对大麻有脱胶效果的碱性果胶酶生产菌株,优化其产果胶酶培养基组成,试验选用果胶作为唯一碳源进行菌株筛选,并采用单因素和正交试验筛选果胶酶发酵培养基组成。结果表明:从沤麻水体中分离到14株具有脱胶能力的细菌,其中X-... 为了分离和鉴定对大麻有脱胶效果的碱性果胶酶生产菌株,优化其产果胶酶培养基组成,试验选用果胶作为唯一碳源进行菌株筛选,并采用单因素和正交试验筛选果胶酶发酵培养基组成。结果表明:从沤麻水体中分离到14株具有脱胶能力的细菌,其中X-6菌果胶酶产量最高,该菌革兰氏阴性,大小为0.6~0.8μm×2~3μm,据其生理生化特征和16SrDNA鉴定,该菌株鉴定并被命名为产碱假单胞菌X-6(Pseudomonas alcaligenes X-6),该菌的最佳产果胶酶培养基组成为葡萄糖5g/L,马铃薯淀粉4g/L,酵母粉4g/L,玉米浆4g/L,氯化钙1.5g/L,氯化钠0.5g/L,经验证在该条件下果胶酶活力达到586U/mL,采用发酵后的粗酶液对大麻进行脱胶试验,残胶率由38.9%降低至17.2%,脱胶效果较好。试验分离和鉴定出一株对大麻脱胶效果较好的菌株,并获得其产果胶酶发酵培养基。 展开更多
关键词 大麻 脱胶 碱性果胶酶 分离 鉴定 优化
在线阅读 下载PDF
盐霉素类似物的分离及抑制吲哚胺2,3-双加氧酶活性研究 预览
20
作者 郑城 王涛 +2 位作者 谢昌贤 云喜报 卢晓霞 《天然产物研究与开发》 CAS CSCD 北大核心 2019年第6期1012-1016,共5页
为研究盐霉素发酵粗产物中的新型盐霉素类活性化合物。实验通过制备色谱从盐霉素发酵粗产物中分离得到两个盐霉素类似物,并利用波谱手段表征了这两个化合物的结构,化合物A为40-甲基盐霉素,化合物B为35-甲基盐霉素,均为新化合物。生物活... 为研究盐霉素发酵粗产物中的新型盐霉素类活性化合物。实验通过制备色谱从盐霉素发酵粗产物中分离得到两个盐霉素类似物,并利用波谱手段表征了这两个化合物的结构,化合物A为40-甲基盐霉素,化合物B为35-甲基盐霉素,均为新化合物。生物活性研究表明,化合物B具有一定的吲哚胺2,3-双加氧酶(IDO)抑制活性。 展开更多
关键词 盐霉素类似物 分离 表征 IDO抑制活性
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部 意见反馈