期刊文献+
共找到297篇文章
< 1 2 15 >
每页显示 20 50 100
经会阴三维超声评价经阴道分娩或剖宫产后女性盆膈裂孔变化的临床研究 被引量:22
1
作者 徐春 单炜丽 《临床超声医学杂志》 2017年第3期178-181,共4页
目的通过经会阴三维超声观察经阴道分娩或剖宫产后女性的膈裂孔的变化情况,探讨生产方式对女性盆底形态的影响。方法选取我院产科分娩后的产妇320例,根据不同分娩方式分为经阴道分娩组(120例)与剖宫产组(200例),另选同期60例我院妇科门... 目的通过经会阴三维超声观察经阴道分娩或剖宫产后女性的膈裂孔的变化情况,探讨生产方式对女性盆底形态的影响。方法选取我院产科分娩后的产妇320例,根据不同分娩方式分为经阴道分娩组(120例)与剖宫产组(200例),另选同期60例我院妇科门诊以阴道炎就诊的未育且无分娩史妇女作为对照组。入选产妇于产后7 d及产后2个月分别行经会阴三维超声检查,对照组于门诊入组时接受经会阴三维超声检查。比较各组盆膈裂孔各项参数。结果经阴道分娩组、剖宫产组产后7 d在静息状态和Valsalva动作下,盆膈裂孔各项参数均大于对照组,差异均有统计学意义(均P<0.05),其中经阴道分娩组盆膈裂孔各项参数均大于剖宫产组,差异均有统计学意义(均P<0.05)。经阴道分娩组、剖宫产组产后2个月在静息状态和Valsalva动作下,盆膈裂孔各项参数均大于对照组,差异均有统计学意义(均P<0.05)。经阴道分娩组静息状态和张力状态下,产后2个月与产后7 d盆膈裂孔面积比较差异均有统计学意义(均P<0.05),其余各项参数比较差异均无统计学意义。剖宫产组静息状态和Valsalva动作下,产后2个月与产后7 d盆膈裂各项参数比较差异均无统计学意义。结论经阴道分娩或剖宫产对产后女性盆底形态均有影响,其中经阴道分娩产后7 d影响大于剖宫产;产后2个月,经阴道分娩产妇盆底修复能力优于剖宫产产妇。经会阴盆底三维超声成像层次全面、清晰度高,能够准确提示不同分娩方式产妇产后早期盆膈裂孔、阴道形态及盆底形态的变化情况,为产后盆底疾病的预测和治疗提供参考。 展开更多
关键词 超声检查 经会阴 阴道分娩 剖宫产 盆底功能
下载PDF
多层螺旋CT后处理技术在胰腺癌诊断及术前评估中的价值 被引量:20
2
作者 周之怀 沈龙山 +1 位作者 刘三春 单连强 《蚌埠医学院学报》 CAS 2017年第7期956-959,共4页
目的:探讨多层螺旋CT(MSCT)后处理技术在胰腺癌诊断及术前评估中的价值。方法:回顾性分析22例胰腺癌病人的CT表现和临床资料,运用MSCT动态三期增强扫描及图像后处理技术,在肿瘤定位诊断基础上,观察周围组织结构受侵犯程度和转移情况;对... 目的:探讨多层螺旋CT(MSCT)后处理技术在胰腺癌诊断及术前评估中的价值。方法:回顾性分析22例胰腺癌病人的CT表现和临床资料,运用MSCT动态三期增强扫描及图像后处理技术,在肿瘤定位诊断基础上,观察周围组织结构受侵犯程度和转移情况;对其中12例行手术的胰腺癌胰周主要血管受侵情况进行术前评估并与手术结果比较。结果:22例胰腺癌中,周围血管受侵19例,胃十二指肠肠壁受侵4例,淋巴结转移6例,肝脾转移11例;CT评估主要血管受侵准确性为88.9%。结论:MSCT增强扫描结合后处理技术能够较准确诊断胰腺癌,为临床术前评估提供重要的参考价值。 展开更多
关键词 胰腺肿瘤 动态增强扫描 后处理技术
下载PDF
济南市2008年-2015年健康人群脑膜炎奈瑟菌带菌状况监测结果分析 被引量:5
3
作者 刘尊玉 聂伟 +3 位作者 刘岚铮 胡光春 单晓英 白爱英 《中国卫生检验杂志》 CAS 2016年第23期3436-3437,3440,共3页
目的了解济南市健康人群脑膜炎奈瑟菌(Nm)携带情况及携带菌的血清群分布情况。方法采集2008年-2015年不同流行时期、不同年龄健康人群的咽拭子标本,用奈瑟菌分离培养基进行分离培养、生化试验、血清学凝集试验。结果 2008年-2015年共检... 目的了解济南市健康人群脑膜炎奈瑟菌(Nm)携带情况及携带菌的血清群分布情况。方法采集2008年-2015年不同流行时期、不同年龄健康人群的咽拭子标本,用奈瑟菌分离培养基进行分离培养、生化试验、血清学凝集试验。结果 2008年-2015年共检测2 362份健康人群咽拭子标本,分离出24株Nm,健康人群平均带菌率为1.02%。其中流行前期带菌率为1.08%,流行期带菌率为1.53%,流行后期带菌率为0.00%。8年间以>7岁人群带菌率较高,<3岁儿童中未检出Nm。检出的24株Nm,A群5株,C群7株,W135群5株,X群2株,B群1株,Y群1株,未分群3株。结论济南市健康人群带菌率处于较低水平,流行前期和流行期带菌率高;中小学生带菌率高;成年人也不可忽视。血清群以A群、C群、W135群为主。 展开更多
关键词 健康人群 脑膜炎奈瑟菌 携带率 血清群
原文传递
北方地区异育银鲫“中科3号”规模化早繁技术 被引量:1
4
作者 刘艳辉 高春山 +3 位作者 刘铁钢 杨炳坤 李秀颖 祖岫杰 《河北渔业》 2021年第5期27-29,共3页
为探索北方地区异育银鲫“中科3号”(Carassius auratus gibelio var.CASⅢ)提早繁殖的可行性,在4月初池塘融冰后,从越冬池塘挑选个体重400 g以上的母本异育银鲫“中科3号”400尾和个体重1500 g左右的父本兴国红鲤80尾,移入阳光温室内... 为探索北方地区异育银鲫“中科3号”(Carassius auratus gibelio var.CASⅢ)提早繁殖的可行性,在4月初池塘融冰后,从越冬池塘挑选个体重400 g以上的母本异育银鲫“中科3号”400尾和个体重1500 g左右的父本兴国红鲤80尾,移入阳光温室内分池强化培育,促使亲鱼性腺快速发育。通过阳光温室提温和人为调控,将温室内池塘水温控制在18.1~22.3℃,高出室外池塘水温5.4~13.6℃。经过22 d强化培育,人工繁殖催产率、受精率、孵化率分别为100%、87.3%、88.8%,共生产水花456.0万尾,每尾雌亲鱼生产水花1.14万尾。异育银鲫“中科3号”提早繁殖较室外池塘自然环境中人工繁殖提前半月左右时间,为延长异育银鲫“中科3号”养殖时间,提高出池规格和增产增收提供了保障。 展开更多
关键词 北方地区 异育银鲫“中科3号”(Carassius auratus gibelio var.CASⅢ) 阳光温室 早繁
下载PDF
产品执行标准标注规定存在的问题及对策
5
作者 张纯义 高春山 《标准化报道》 2000年第6期34-36,共3页
针对产品在执行标准标注方面存在的要求不统一、表述不一致问题进行探讨,并提出相应的对策建议。
关键词 产品 标注 执行标准 企业 规定 称谓规范
下载PDF
The effect of the amount of ammonia on the Cu^0/Cu^+ ratio of Cu/SiO_2 catalyst for the hydrogenation of dimethyl oxalate to ethylene glycol 被引量:10
6
作者 Feng Li chun-shan Lu Xiao-Nian Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第11期1461-1465,共5页
The effect of the amount of precipitant ammonia on the Cu0/Cu+ratio of Cu/Si O2 prepared by the deposition–precipitation method is investigated. Species at different preparation stages, resulted from the amount of a... The effect of the amount of precipitant ammonia on the Cu0/Cu+ratio of Cu/Si O2 prepared by the deposition–precipitation method is investigated. Species at different preparation stages, resulted from the amount of ammonia used, are identified by the XRD and FTIR techniques. Chrysocolla together with either copper nitrate hydroxide or copper hydroxide coexist in the uncalcined catalysts. Upon calcination, the latter two species are converted to Cu O particles while chrysocolla remains. Following reduction, Cu O is transformed to metallic Cu and chrysocolla is converted to Cu2 O. The value of Cu0/Cu+ratio can be evaluated using the peak areas in their TPR profiles. Hydrogenation of dimethyl oxalate(DMO) to ethylene glycol(EG) shows that the selectivity of EG depends on the Cu0/Cu+ratio. Catalyst prepared with the addition of ammonia solution at n(NH3)/n(Cu2+) = 0.9 for precipitation–deposition gains a more suitable Cu0/Cu+ratio upon reduction and thus has a higher selectivity for EG. 展开更多
关键词 Amount of ammonia Deposition–precipitation Chrysocolla Copper nitrate hydroxide Copper hydroxide DMO hydrogenation
原文传递
Efficacy of a Chinese herbal formula on hepatitis B e antigenpositive chronic hepatitis B patients 被引量:9
7
作者 Yu-Feng Xing chun-shan Wei +23 位作者 Tian-Ran Zhou Dan-Ping Huang Wei-Chao Zhong Bin Chen Hua Jin Xiao-Yu Hu Zhi-Yun Yang Qing He Kai-Ping Jiang Jun-Min Jiang Zhen-Bin Hu Xin Deng Fan Yang Feng-Yi Li Gang Zhao Li-chun Wang Yu-Qiang Mi Zuo-Jiong Gong Peng Guo Jian-Hua Wu Wei-Qun Shi Hong-Zhi Yang Da-Qiao Zhou Guang-Dong Tong 《World Journal of Gastroenterology》 SCIE CAS 2020年第30期4501-4522,共22页
BACKGROUND No guideline recommends antiviral therapy for hepatitis B e antigen(HBeAg)-positive chronic hepatitis B patients with persistently normal alanine aminotransferase levels and a high hepatitis B virus(HBV)DNA... BACKGROUND No guideline recommends antiviral therapy for hepatitis B e antigen(HBeAg)-positive chronic hepatitis B patients with persistently normal alanine aminotransferase levels and a high hepatitis B virus(HBV)DNA viral load.AIM To evaluate the feasibility and safety of a Chinese herbal formula as a therapeutic option for chronic HBV infection.METHODS In total,395 patients(30–65 years old)with confirmed HBeAg-positive chronic hepatitis B infection and persistently normal alanine aminotransferase were randomized to receive either Chinese herbal formula or placebo for 96 wk.Endpoints to evaluate therapeutic efficacy included:(1)HBV DNA levels decreased to less than 4 log10 IU/mL at weeks 48 and 96;and(2)HBeAg clearance and seroconversion rates at weeks 48 and 96.RESULTS HBV DNA levels≤4 log10 IU/mL were 10.05%at week 48 and 18.59%at week 96 in the treatment group.The HBeAg clearance and conversion rates were 8.54%and 8.04%at week 48 and 16.08%and 14.57%at week 96,respectively.However,HBV DNA levels≤4 log10 IU/mL were 2.55%and 2.55%at weeks 48 and 96,respectively,and the HBeAg clearance rates were 3.06%and 5.61%at weeks 48 and 96,respectively,in the control group.The quantitative hepatitis B surface antigen and HBeAg levels at baseline and changes during the treatment period as well as the alanine aminotransferase elevation at weeks 12 and 24 were strong predictors of HBeAg clearance.CONCLUSION High rates of HBV DNA reduction,HBeAg clearance and seroconversion could be achieved with Chinese herbal formula treatments,and the treatments were relatively safe for HBeAg-positive chronic hepatitis B-infected patients with persistently normal alanine aminotransferase.The ability of the compound to modulate host immune function probably contributed to this effect. 展开更多
关键词 Chronic hepatitis B Chinese Herbal Formula treatment Hepatitis B e antigen clearance Hepatitis B e antigen seroconversion Hepatitis B virus DNA reduction Clinical trial
下载PDF
Behavior of adsorbed diphenyl-sulfide on the Pd/C catalyst for o-chloronitrobenzene hydrogenation 被引量:9
8
作者 Chang Su Xiao-Nian Li +3 位作者 Qun-Feng Zhang Lei Ma chun-shan Lu Feng Feng 《Chinese Chemical Letters》 SCIE CAS CSCD 2013年第1期59-62,共4页
A series of diphenyl-sulfide (Ph2S)-immobilized Pd/C catalysts (Pd-Ph2Scx)/C) were prepared using the wetness-impregnation and immobilization method. Pd-Ph2S(x)/C catalysts employed for the hydro- genation of o... A series of diphenyl-sulfide (Ph2S)-immobilized Pd/C catalysts (Pd-Ph2Scx)/C) were prepared using the wetness-impregnation and immobilization method. Pd-Ph2S(x)/C catalysts employed for the hydro- genation of o-chloronitrobenzene showed very high selectivity. The structure of Pd-Ph2Scx)/C with different molar ratio of ligand (x-values) was characterized by XPS and TG-DSC-MS. The results suggest a "saturated" surface ratio of Ph2S/Pd (about 0.3) was formed on the Pd-Ph2S(x)[C catalysts surface. The Ph2S immobilized on the Pd particle is quite stable, and the desorption of Ph2S or dissociative loss of phenyl group was only found at temperatures above 500 K. The possible catalytic mechanism of the Pd-Ph2S(x)/C catalyst was also discussed. 展开更多
关键词 Pd-Ph2S(x)/C O-CHLORONITROBENZENE HYDROGENATION
原文传递
New tight junction protein 2 variant causing progressive familial intrahepatic cholestasis type 4 in adults: A case report 被引量:6
9
作者 chun-shan Wei Naja Becher +3 位作者 Jenny Blechingberg Friis Peter Ott Ida Vogel Henning Grønbæk 《World Journal of Gastroenterology》 SCIE CAS 2020年第5期550-561,共12页
BACKGROUND Progressive familial intrahepatic cholestasis(PFIC)encompasses a group of autosomal recessive disorders with high morbidity and mortality.Variants in the gene encoding tight junction protein-2(TJP2)have bee... BACKGROUND Progressive familial intrahepatic cholestasis(PFIC)encompasses a group of autosomal recessive disorders with high morbidity and mortality.Variants in the gene encoding tight junction protein-2(TJP2)have been linked to PFIC type 4(PFIC4),which predominantly presents in childhood.However,there are only limited data from adults with TJP2-related PFIC4.We report a family with an autosomal recessive disorder with a novel variant in the TJP2 gene in adults with very variable expression of PFIC4.CASE SUMMARY The index patient presented at 19 years old with liver cirrhosis and variceal bleeding and was treated with endoscopic banding and beta-blockers.In 2018,he developed primary liver cancer that was treated with radiofrequency ablation followed by liver transplantation in 2019.Genetic testing revealed a novel homozygous TJP2 variant causing PFIC4(TJP2([NM_004817.3]:c.[3334C>T];[3334C>T])).The consanguineous family consists of the father and mother(both heterozygous)and their 12 children,of which five carry the variant in a homozygous state;however,these five siblings have highly variable expression of PFIC4.Two homozygous brothers had cirrhosis and portal hypertension at diagnosis at the ages of 19 and 36.Two other homozygous brothers,age 23 and 19,and the homozygous sister,age 21,have elevated liver enzymes but presently no cirrhosis,which may suggest an age-dependent penetrance.In addition,five sisters had severe and mild intrahepatic cholestasis of pregnancy and carry the TJP2 variant in a homozygous and heterozygous state,respectively.CONCLUSION This novel TJP2 variant is associated with PFIC4 causing severe liver disease with cirrhosis and primary liver cancer in adolescents/adults. 展开更多
关键词 Progressive familial intrahepatic cholestasis Tight junction protein 2 Genetic variants Liver cirrhosis Liver cancer Case report
下载PDF
Long-term follow-up of cumulative incidence of hepatocellular carcinoma in hepatitis B virus patients without antiviral therapy 被引量:6
10
作者 Xiao-Yan Jiang Bing Huang +5 位作者 Dan-Ping Huang chun-shan Wei Wei-Chao Zhong De-Ti Peng Fu-Rong Huang Guang-Dong Tong 《World Journal of Gastroenterology》 SCIE CAS 2021年第11期1101-1116,共16页
BACKGROUND China has a high prevalence of hepatitis B virus(HBV),but most chronic hepatitis B(CHB)patients do not receive standardized antiviral therapy.There are few relevant reports addressing the outcomes of the la... BACKGROUND China has a high prevalence of hepatitis B virus(HBV),but most chronic hepatitis B(CHB)patients do not receive standardized antiviral therapy.There are few relevant reports addressing the outcomes of the large number of CHB patients who do not receive antiviral therapy.AIM To observe the outcomes of long-term follow-up of patients with CHB without antiviral treatment.METHODS This study included 362 patients with CHB and 96 with hepatitis B cirrhosis without antiviral treatment and with only liver protection and anti-inflammatory treatment from 1993 to 1998.The median follow-up times were 10 and 7 years,respectively.A total of 203 CHB and 129 hepatitis B cirrhosis patients receiving antiviral therapy were selected as the control groups.The median follow-up times were 8 and 7 years,respectively.Kaplan-Meier curves were used to analyze the cumulative incidence of hepatocellular carcinoma(HCC),and the Cox regression model was used to analyze the risk factors for HCC.RESULTS Among the patients in the non-antiviral group,16.9%had spontaneous decreases(HBeAg)seroconversion.In the antiviral group,87.2%of patients had undetectable HBV DNA,and 52%showed HBeAg seroconversion.Among CHB and hepatitis B cirrhosis patients,the cumulative incidence rates of HCC were 14.9%and 53.1%,respectively,in the non-antiviral group and were 10.7%and 31.9%,respectively,in the antiviral group.There was no difference between the two groups regarding the CHB patients(P=0.842),but there was a difference between the groups regarding the hepatitis B cirrhosis patients(P=0.026).The cumulative incidence rates of HCC were 1.6%and 22.3%(P=0.022)in the groups with and without spontaneous HBeAg seroconversion,respectively.The incidence rates of HCC among patients with and without spontaneous declines in HBV DNA to undetectable levels were 1.6%and 19.1%,respectively(P=0.051).There was no difference in the cumulative incidence of HCC between the two groups regarding the patients with drug-resistant CHB(P=0.119),but there was a significant diffe 展开更多
关键词 Chronic hepatitis B Anti-inflammatory therapy Hepatoprotective therapy Cumulative incidence Hepatocellular carcinoma Antiviral therapy
下载PDF
Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation 被引量:5
11
作者 MA Chang-shen DONG Jian-zeng LIU Xing-peng LONG De-yong FANG Dong-ping HU Fu-li YU Rong-hui TANG Ri-bo HAO Peng LU chun-shan 《Chinese Medical Journal》 SCIE CAS CSCD 2006年第7期551-556,共6页
Background Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary ... Background Pulmonary vein (PV) isolation has been developed to treat patients with atrial fibrillation (AF), and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials (PVPs). Pulmonary vein tachycardia (PVT) is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear. Methods From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation (SPVA) or circumferential pulmonary vein ablation (CPVA). PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length (CL) of 〈300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student's t test and categorical variables were analyzed by chi-square test. Results Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs (including 790 PVs) were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% (992/1105) of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % (113/1105) of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of (155±43) ms (2 PYTs in 2 patients received SPYA, 26 PYTs in 18 patients underwent CPVA). PVT was more frequently documented in patients underwent CPVA approach [9.0% (18/200) vs 2.3% (2/85), P=0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between pa 展开更多
关键词 atrial fibrillation pulmonary vein tachycardia
原文传递
M2 exosomes modified by hydrogen sulfide promoted bone regeneration by moesin mediated endocytosis 被引量:1
12
作者 Yi-kun Zhou chun-shan Han +7 位作者 Zi-lu Zhu Peng Chen Yi-ming Wang Shuai Lin Liu-jing Chen Zi-meng Zhuang Yan-heng Zhou Rui-li Yang 《Bioactive Materials》 SCIE CSCD 2024年第1期192-205,共14页
Bone defects caused by trauma or tumor led to high medical costs and poor life quality for patients.The exosomes,micro vesicles of 30-150 nm in diameter,derived from macrophages manipulated bone regeneration.However,t... Bone defects caused by trauma or tumor led to high medical costs and poor life quality for patients.The exosomes,micro vesicles of 30-150 nm in diameter,derived from macrophages manipulated bone regeneration.However,the role of hydrogen sulfide(H2S)in the biogenesis and function of exosomes and its effects on bone regeneration remains elusive.In this study,we used H2S slow releasing donor GYY4137 to stimulate macrophages and found that H2S promoted the polarization of M2 macrophages to increase bone regeneration of MSCs in vitro and in vivo.Moreover,we developed the H2S pre-treated M2 macrophage exosomes and found these exosomes displayed significantly higher capacity to promote bone regeneration in calvarial bone defects by re-establishing the local immune microenvironment.Mechanically,H2S treatment altered the protein profile of exosomes derived from M2 macrophages.One of the significantly enriched exosomal proteins stimulated by H2S,moesin protein,facilitated the exosomes endocytosis into MSCs,leading to activated theβ-catenin signaling pathway to promote osteogenic differentiation of MSCs.In summary,H2S pretreated M2 exosomes promoted the bone regeneration of MSCs via facilitating exosomes uptake by MSCs and activateβ-catenin signaling pathway.This study not only provides new strategies for promoting bone regeneration,but also provides new insights for the effect and mechanism of exosomes internalization. 展开更多
关键词 MACROPHAGES EXOSOMES Bone regeneration Stem cells Hydrogen sulfide MOESIN
原文传递
Improvement of the stability of Hg/AC catalysts by CsCl for the high-temperature hydrochlorination of acetylene 被引量:4
13
作者 Xiao-Long Xu Jia Zhao +4 位作者 chun-shan Lu Tong-Tong Zhang Xiao-Xia Di shan-Chuan Gu Xiao-Nian Li 《Chinese Chemical Letters》 SCIE CAS CSCD 2016年第6期822-826,共5页
Activated carbon-supported mercuric chloride(HgCl2) is used as an industrial catalyst for acetylene hydrochlorination. However, the characteristic of easy sublimation of HgCl2 leads to the deactivation o the catalys... Activated carbon-supported mercuric chloride(HgCl2) is used as an industrial catalyst for acetylene hydrochlorination. However, the characteristic of easy sublimation of HgCl2 leads to the deactivation o the catalyst. Here, we showed that the thermal stability of the Hg/AC catalyst can be evidently improved when Cs Cl is added into the Hg/AC catalyst. Compared with the pure Hg/AC catalyst, the sublimation rate of HgCl2 from the Hg–Cs/AC catalyst decreased significantly and the Hg–Cs/AC catalyst showed bette catalytic activity and stability in the reaction. This promoting effect is related to the existence of cesium mercuric chlorides(CsxHgyCl(x+2y)) highlighted by XRD, HR-TEM and EDX analyses. Thus, reacting HgCl2 with alkali chlorides to form alkali-mercuric chlorides may be a key to design highly efficient and thermally stable mercuric chloride catalyst for hydrochlorination reactions. 展开更多
关键词 Cesium chloride Mercuric chloride SUBLIMATION Hydrochlorination of acetylene Cesium–mercuric chlorides
原文传递
CATALYTIC RESEARCH FOR CLEAN ENERGY AND ULTRA-CLEAN FUELS IN THE 21^(st) CENTURY Future Perspectives 被引量:4
14
作者 chun-shan SONG (Clean Fuels and Catalysis Program, The Energy Institute, and Department of Energy & Geo-Environmnetal Engineering, Pennsylvania State University, 209 Academic Projects Building, University Park, PA 16802, USA) 《石油学报(石油加工)》 EI CAS CSCD 北大核心 2002年第6期1-19,共19页
本文系由大连理工大学王祥生教授 (本刊编委 )和郭新闻教授约请美国宾州大学宋春山博士撰写的“2 1世纪清洁能源和超清洁燃料催化研究的未来展望”述评。在本文中笔者系统而扼要地回顾了 2 0世纪全球能源消耗及供求的情况 ,展望了 2 1... 本文系由大连理工大学王祥生教授 (本刊编委 )和郭新闻教授约请美国宾州大学宋春山博士撰写的“2 1世纪清洁能源和超清洁燃料催化研究的未来展望”述评。在本文中笔者系统而扼要地回顾了 2 0世纪全球能源消耗及供求的情况 ,展望了 2 1世纪催化研究面临的机遇 ,着重讨论了清洁能源 ,对催化而言应把综合和有效利用能源作为研究方向。笔者结合美国情况介绍了许多有用的统计数字 ,重点结合自己的研究工作比较全面地阐述了能源燃料工业对催化研究的需求及其机遇。它包括了清洁运输燃料、重油轻质化增产中间馏分油、制氢和燃料电池、天然气利用、天然气液化、替代燃料的发展、煤的综合利用、专用化学品的合成以及CO2 的转化和利用等。煤既作为生产清洁燃料的原料 ,又作为生产专用化学品的资源 ,把在炼油化工中已经取得卓越成果的催化技术、分子筛催化过程转移到煤化工领域 ,笔者对此提出了比较完整的方案。这些对于读者都有很大的帮助。 展开更多
关键词 燃料工业 催化作用 催化技术 清洁催化剂 无污染 清洁燃料
下载PDF
Holographic Gas as Dark Energy 被引量:4
15
作者 LI Miao LI Xiao-Dong +1 位作者 LIN chun-shan WANG Yi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第1期181-186,共6页
We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modif... We investigate the statistical nature of holographic gas, which may represent the quasi-particle excitations of a strongly correlated gravitational system. We find that the holographic entropy can be obtained by modifying degeneracy. We calculate thermodynamical quantities and investigate stability of the holographic gas. When applying to cosmology, we find that the holographic gas behaves as holographic dark energy, and the parameter c in holographic dark energy can be calculated from our model. Our model of holographic gas generally predicts c 〈 1, implying that the fate of our universe is phantom-like. 展开更多
关键词 holographic principle dark energy
下载PDF
Characteristics, Enzymatic Extraction of Pectin from Shaddock 被引量:4
16
作者 XIE Lian-wu GUO Ya-ping ZHOU chun-shan 《Journal of Northeast Agricultural University(English Edition)》 CAS 2005年第2期105-107,共3页
Pectins had been extracted from shaddock raw material with 0.01 mol·L^-1 HCI and with three enzymic preparations including cellulase from aspergillus oryzaei.β -glucosidase from almonds and protopectinases-T, a ... Pectins had been extracted from shaddock raw material with 0.01 mol·L^-1 HCI and with three enzymic preparations including cellulase from aspergillus oryzaei.β -glucosidase from almonds and protopectinases-T, a protopectin-solubilizing enzyme, which did not degrade polygalacturonic acid, The effects of enzymic and acid soluhilization of pectin from shaddock materials were compared, The yield of pectin preparations, degree of acetylation, gelling strength, molecular weight and viscosity were determined. Enzymic methods of extraction gave much bigger yields of pectic substances. Compared with the pectin extracted with hydrochloric acid, all the samples derived from shaddock raw material with enzymic preparations had a significant lower D-galacturonic acid content. 展开更多
关键词 SHADDOCK enzymic extraction PECTIN
下载PDF
The promoting role of minor amount of water in solvent-free hydrogenation of halogenated nitrobenzenes 被引量:3
17
作者 Jing-Hui Lyu Xiao-Bo He +5 位作者 chun-shan Lu Lei Ma Qun-Feng Zhang Feng Feng Xiao-Nian Li Jian-Guo Wang 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第2期205-208,共4页
This study shows that minor amount of water plays a very important role in solvent-free hydrogenation of halogenated nitrobenzenes. For dried sponge Pd, the reaction cannot occur in the absence of water. For Pd/C cata... This study shows that minor amount of water plays a very important role in solvent-free hydrogenation of halogenated nitrobenzenes. For dried sponge Pd, the reaction cannot occur in the absence of water. For Pd/C catalyst, minor amount of water reduces the induction time, increases the reaction rate and reaction TOFs. Water might enhance the diffusion, adsorption and dissociation of H2 on Pd catalysts. 展开更多
关键词 Halogenated nitrobenzenes Solvent Free WATER HYDROGENATION
原文传递
Extraction Separation of Germanium with Hydroxamic Acid HGS98 被引量:2
18
作者 TANG Shu-fang ZHOU chun-shan +1 位作者 JIANG Xin-yu ZHAO chun-lei 《Journal of Central South University》 SCIE EI CAS 2000年第1期40-42,共3页
The extraction separation of germanium from indium raffinate in hydrometallurgical zinc process was discussed. The conditions and mechanism of the extraction with hydroxamic acid HGS98 have been investigated in detail... The extraction separation of germanium from indium raffinate in hydrometallurgical zinc process was discussed. The conditions and mechanism of the extraction with hydroxamic acid HGS98 have been investigated in detail. The results show that u sing 2% (mass fraction) hydroxamic acid HGS98 and 5% D 2EHPA as synergist, germanium is extracted (1 stage) over 99% in 5 min at phase ratio ( V o∶ V a) of 1∶5 from indium raffinate with original acidity. Then, using 2 mol·L -1 NH 4F as strip liquor, the stripping recovery is over 98% in 15 min at phase ratio of 1∶1. This process has the following advantages:easy to operate, high recovery and selectivity, and lower investment cost. It provides a new way to recover rare metal-germanium from metallurgical spent residues. 展开更多
关键词 EXTRACTION SEPARATION GERMANIUM hydroxamic ACID HGS98
下载PDF
Initial experience with ablation of the innervation surrounding sinus and atrioventricular nodes to treat paroxysmal bradyarrhythmia 被引量:2
19
作者 chun-shan Lu Cheng-Jun Guo +3 位作者 Dong-Ping Fang Peng Hao Dong-Fang He Ai-Guo Xu 《Chinese Medical Journal》 SCIE CAS CSCD 2020年第2期134-140,共7页
Background:The symptomatic bradyarrhythmia is Class I indication for pacing therapy which is not a radical cure.The present study aimed to assess the feasibility and to present the initial results of the restricted ab... Background:The symptomatic bradyarrhythmia is Class I indication for pacing therapy which is not a radical cure.The present study aimed to assess the feasibility and to present the initial results of the restricted ablation of the parasympathetic innervation surrounding sinus and atrioventricular(AV)nodes for treating patients with bradyarrhythmia.Methods:A total of 13 patients with cardiogenic syncope were included from May 2008 to June 2015.Under the guidance of fluoroscopy and/or three-dimensional geometry by 64-slice spiral computed tomography,atrial activation sequence in sinus rhythm was mapped.Chamber geometry was reconstructed manually or automatically using the Niobe II magnetic navigation system integrated with the CARTO-remote magnetic technology(RMT)system.Cardioneuroablation was targeted at the high-amplitude fractionated electrograms surrounding the regions of His bundle and the site with the earliest activation in sinus rhythm.Areas surrounding the sinus node,AV node,and the phrenic nerve were avoided.Results:Thirteen patients completed the studies.Ablation was successfully performed in 12 patients and failed in one.The highfrequency potential was recorded in atrial electrograms surrounding the sinus or AV nodes in all the patients and disappeared in 15 s after radiofrequency applications.The vagal reaction was observed before the improvement of the sinus and AV node function.No complications occurred during the procedures.Patients were followed up for a mean of 13.0±5.9 months.During the follow up ten patients remained free of symptoms,and two patients had a permanent cardiac pacemaker implanted due to spontaneous recurrence of syncope.The heart rate of post-ablation was higher than pre-ablation(69.0±11.0 vs.49.0±10.0 beats/min,t=4.56,P=0.008).The sinus node recovery time,Wenckebach block point,and atrium-His bundle interval were significantly shorter after ablation(1386.0±165.0 vs.921.0±64.0 ms,t=7.45,P=0.002;590.0±96.0 vs.464.0±39.0 ms,t=2.38,P=0.023;106.0±5.0 vs.90.0±12.0 ms,t=9.80,P=0 展开更多
关键词 ELECTROPHYSIOLOGY Radiofrequency ablation SINUS node dysfunction Atrioventricular block SYNCOPE
原文传递
Distributed Capacitance of Coaxial Line With Perturbed Walls 被引量:2
20
作者 PENG Bao-quan FU Wen-bin YANG chun-shan ( Department of Physics, Huazhong University of Science and Technology,Wuhan 430074,China Microwave Engineering Department,Air Force Radar Academy,Wuhan 430010,China) 《Wuhan University Journal of Natural Sciences》 CAS 2000年第1期80-82,共3页
Perturbation method of boundary geometry(PMOBG) used in Lapiacian problems is dealt with and the three--term perturbation expression of distributed capacitance of a coaxial line with perturbed walls is obtained. As an... Perturbation method of boundary geometry(PMOBG) used in Lapiacian problems is dealt with and the three--term perturbation expression of distributed capacitance of a coaxial line with perturbed walls is obtained. As an example,four-order expression of distributed capacitance of a elliptic coaxial line with small eccentricity is given. 展开更多
关键词 perturbation method of boundary geometry coaxial line perturbed wall distributed capacitance
下载PDF
上一页 1 2 15 下一页 到第
使用帮助 返回顶部