期刊文献+
共找到280篇文章
< 1 2 14 >
每页显示 20 50 100
INTERGROWTH-21^(st)标准评价胎儿宫内生长受限的临床价值 被引量:10
1
作者 朱晨 任芸芸 吴江南 《复旦学报(医学版)》 CAS CSCD 北大核心 2017年第3期307-311,325,共6页
目的探讨INTERGROWTH-21^(st)标准评价胎儿宫内生长受限的应用价值。方法本研究为前瞻性队列研究。收集2015年3月至2016年3月在复旦大学附属妇产科医院建卡,进行常规产前检查并入院分娩的单胎妊娠孕妇。所有入选病例孕28周之后入组,每4... 目的探讨INTERGROWTH-21^(st)标准评价胎儿宫内生长受限的应用价值。方法本研究为前瞻性队列研究。收集2015年3月至2016年3月在复旦大学附属妇产科医院建卡,进行常规产前检查并入院分娩的单胎妊娠孕妇。所有入选病例孕28周之后入组,每4周做一次产前超声生长测量,直至分娩前。胎儿生长径线以INTERGROWTH-21^(st)标准计算Z-score值。分娩后随访新生儿体重等相关信息。应用Logistic回归方程建立预测公式。最后将新公式与Hadlock法预测IUGR的准确性进行对比。结果共收集符合入组条件的孕妇834例。排除失访143例后,得到对照组565例和IUGR组126例。新预测公式的敏感性、特异性、阳性预测值、阴性预测值、假阳性率、假阴性率分别为:88.9%、85.4%、57.7%、97.2%、14.6%、11.1%。Hadlock法预测的敏感性、特异性、阳性预测值、阴性预测值、假阳性率、假阴性率分别为:81.7%、82.7%、51.2%、95.3%、17.3%、18.3%。结论以INTERGROWTH-21^(st)标准计算Z-score建立新公式预测胎儿宫内生长受限的方法,与传统的Hadlock预测法相比,改善了产前诊断的敏感性和特异度,减少了假阳性和假阴性的病例,全面提高了超声预测胎儿宫内生长受限的准确性。 展开更多
关键词 intergrowth-21st Z-SCORE 胎儿宫内生长受限 超声生长测量 晚孕期
下载PDF
Effects of Rice-duck Mutualism on Diseases Insect Pests and Weeds and Economic Benefits 被引量:1
2
作者 邓强辉 潘晓华 《Agricultural Science & Technology》 CAS 2008年第1期128-133,138,共7页
[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mu... [Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mutualism, conventional cultivation and control treatment, the yield and economic benefits were analyzed under the 3 treatments. [Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.0g ind/m^2 compared with that in conventional cultivation and control treatment ; the control rate of mutualism was up to 75% against rice hopper, but just between 25% -60% against rice leaf roller and Chilo suppressalis. The rates of diseased plant and diseased bell against rice sheath blight were higher and disease indices were lower compared with control group. The yield of mutualism group was identical with conventional cultivation, Which was greatly higher than that of control group. The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment. [Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases, insect pests and weeds, as well as to economic benefits, providing basis on extension of rice-duck mutualism system. 展开更多
关键词 rice-duck mutualism Disease insect pest and weeds Economic benefits
下载PDF
Hydroisomerization performance of platinum supported on ZSM-22/ZSM-23 intergrowth zeolite catalyst 被引量:9
3
作者 Chi Kebin Zhao Zhen +8 位作者 Tian Zhijian Hu Sheng Yan Lijun Li Tianshu Wang Bingchun Meng Xiangbin Gao Shanbin Tan Mingwei Liu Yanfeng 《Petroleum Science》 SCIE CAS CSCD 2013年第2期242-250,共9页
Hydroisomerization catalysts Pt/ZSM-22, Pt/ZSM-23, and Pt/ZSM-22/ZSM-23 were prepared by supporting Pt on ZSM-22, ZSM-23, and intergrowth zeolite ZSM-22/ZSM-23, respectively. The typical physicochemical properties of ... Hydroisomerization catalysts Pt/ZSM-22, Pt/ZSM-23, and Pt/ZSM-22/ZSM-23 were prepared by supporting Pt on ZSM-22, ZSM-23, and intergrowth zeolite ZSM-22/ZSM-23, respectively. The typical physicochemical properties of these catalysts were characterized by X-Ray Diffraction (XRD), N2 absorption-desorption, Pyridine-Fourier Transform Infrared (Py-FTIR), Transmission Electron Microscopy (TEM), X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM) and NH3- Temperature Programmed Desorption (NH3-TPD), and the performance of these catalysts in n-dodecane hydroisomerization was evaluated in a continuous down-flow fixed bed with a stainless steel tubular reactor. The characterization results indicated that the intergrowth zeolite ZSM-22/ZSM-23 possessed the dual structure of ZSM-22 and ZSM-23, and the catalyst Pt/ZSM-22/ZSM-23 had similar pores and weak acidity to Pt/ZSM-22 and Pt/ZSM-23 catalysts. Moreover, Pt/ZSM-22/ZSM-23 catalyst showed a high selectivity in hydroisomerization of long chain n-alkanes to mono-branched isomers. The evaluation results for n-dodecane hydroisomerization indicated that the activity of Pt/ZSM-22/ZSM-23 was the lowest, while the hydroisomerization selectivity was the highest among the three catalysts. The maximum yield of i-dodecane product was 68.3% over Pt/ZSM-22/ZSM-23 at 320 ℃. 展开更多
关键词 ZSM-22/ZSM-23 intergrowth zeolite platinum catalyst N-DODECANE HYDROISOMERIZATION
下载PDF
Rice-duck co-culture benefits grain 2-acetyl-1-pyrroline accumulation and quality and yield enhancement of fragrant rice 被引量:9
4
作者 Meijuan Li Ronghua Li +3 位作者 Shiwei Liu Jia'en Zhang Hao Luo Shuqing Qiu 《The Crop Journal》 SCIE CAS CSCD 2019年第4期419-430,共12页
Rice-duck co-culture is an integrated farming technology that benefits rice production, grain quality, and ecological sustainability in paddy fields. However, little is known about the effects of rice-duck co-culture ... Rice-duck co-culture is an integrated farming technology that benefits rice production, grain quality, and ecological sustainability in paddy fields. However, little is known about the effects of rice-duck co-culture on enzyme activity involved in the biosynthesis of 2-acetyl-1-pyrroline (2-AP), the volatile that gives fragrant rice its' distinctive and sought-after aroma. The present study aimed to examine the influence of rice-duck co-culture on the photosynthesis, yield, grain quality, rice aroma, and the enzymes involved in 2-acetyl-1-pyrroline biosynthesis in the cultivar Meixiangzhan 2 during the early and late rice growing seasons of 2016 in Guangzhou, China. We compared the rice grown in paddy fields with and without ducks. We found that rice-duck co-culture not only improved the yield and quality of fragrant rice grain, but also promoted the precursors of 2-AP biosynthesis formation and 2-AP accumulation in the grain. Grain 2-AP content in rice-duck co-culture was noticeably increased with 9.60% and 20.81% in early and late seasons, respectively. Proline and pyrroline-5-carboxylic acid (P5C) (precursors of 2-AP biosynthesis) and the activity of enzymes such as proline dehydrogenase (ProDH), ornithine aminotransferase (OAT) and Δ1 pyrroline-5-carboxylic acid synthetase (P5CS) were all improved by 10.15%–12.99%, 32.91%–47.75%, 17.81%–26.71%, 6.25%–21.78%, and 10.58%–38.87% under rice-duck co-culture in both seasons, respectively. Overall, our results suggest that rice-duck co-culture is an environmentally-friendly and sustainable approach to improving rice aroma and grain quality of fragrant rice. 展开更多
关键词 rice-duck CO-CULTURE 2-AP Proline Yield GRAIN QUALITY FRAGRANT RICE
下载PDF
Influencing Factors on Rice Sheath Blight Epidemics in Integrated Rice-Duck System 被引量:6
5
作者 SU Pin LIAO Xiao-lan +1 位作者 ZHANG Ya HUANG Huang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第9期1462-1473,共12页
Sheath blight, a disease caused by the fungus Rhizoctonia solani Kuhn (anamorph), has been the most economically significant disease of rice. It was frequently reported that the disease was well-controlled in integr... Sheath blight, a disease caused by the fungus Rhizoctonia solani Kuhn (anamorph), has been the most economically significant disease of rice. It was frequently reported that the disease was well-controlled in integrated rice-duck system without the employment of fungicides. However, the effecting factors behind this phenomenon were rarely reported. In this research, experiment was carried out between two treatments, rice combined with ducks (RD) and conventional rice field without ducks rearing (CK) in early season rice paddy, to investigate the variations of sclerotia in floodwater and on rice plant, microclimate 10 cm above the waterline in rice paddy and activity of protective enzymes in rice plants. The results showed that the floating sclerotia in floodwater in RD was 86-91% lower than that in CK, and adhering sclerotia in rice plant in RD was 67-78% lower than that in CK. The relative humidity tested significantly lower and light intensity tested significantly higher in RD. The temperature in the early rice growth stages in RD was slightly lower than that in CK, but it was significantly higher (32.3-36.5~C) in the middle stage rice growth stages. The polyphenoloxidase (PPO) activity in RD were lower than that in CK, but the enhanced activity of phenylalanine ammonia-lyase (PAL), peroxidase (POD) and Chitinase was observed in different stages of rice growth in RD, especially the Chitinase which showed higher activity in all investigating days. 展开更多
关键词 rice sheath blight integrated rice-duck system SCLEROTIA MICROCLIMATE protective enzyme
下载PDF
Rainfall,Landslide and Debris Flow Intergrowth Relationship in Jiangjia Ravine 被引量:5
6
作者 HU Mingjian WANG Ren SHEN Jianhua 《Journal of Mountain Science》 SCIE CSCD 2011年第4期603-610,共8页
Jiangjia Ravine is a world-famous debris flow valley in Dongchuan,Yunnan Province,China.Every year large numbers of landslides and collapses happened and caused enormous damages to people's properties and lives.Wi... Jiangjia Ravine is a world-famous debris flow valley in Dongchuan,Yunnan Province,China.Every year large numbers of landslides and collapses happened and caused enormous damages to people's properties and lives.With longtime observation and testing in Jiangjia Ravine we had found out one kind of special landslide which had the characteristics of landslide and collapse.Landslide and collapse supplied sufficient materials for debris flow.When a debris flow broke out,some kind of intergrowth existed among rainfall,landslide and debris flow.In order to study the intergrowth and some key parameters,we carried out artificial rainfall landslide tests and model experiments to observe the phenomena such as collapse,surface slide and surface flow.By observing the experimental phenomena and monitoring water contents,the transformation process among landslide deposits and debris flow under the condition of rainfall had been analyzed.Research results revealed the relationship of this kind of intergrowth among rainfall,landslide and debris flow in Jiangjia Ravine.Meanwhile,it was found that this kind of intergrowth relationship existed only when the moisture content was in a certain range.That is,the critical state seemed to be existed in the transformation process. 展开更多
关键词 LANDSLIDE DEBRIS-FLOW RAINFALL intergrowth Moisture Content Jiangjia Ravine
下载PDF
Studies on Technique of Reducing Methane Emission in a Rice-Duck Ecological System and the Evaluation of Its Economic Significance 被引量:5
7
作者 XIANG Ping-an HUANG Huang +3 位作者 HUANG Mei GAN De-xin ZHOU Yan FU Zhi-qiang 《Agricultural Sciences in China》 CAS CSCD 2006年第10期758-766,共9页
The rice-duck ecological system is one of the major practices of the traditional Chinese agriculture. A study on the effect of reducing methane emission using this practice provided theoretical and practical basis for... The rice-duck ecological system is one of the major practices of the traditional Chinese agriculture. A study on the effect of reducing methane emission using this practice provided theoretical and practical basis for further development and utilization of this classical agricultural technique. The effect of reducing methane emission and the economic benefits of rice-duck ecological system were studied by carrying out a field experiment and by using economic methodology. The daily variation of CH4 emission in late rice paddy field was basically consistent with the daily variation of atmospheric temperature. The highest emission occurred at the full tillering stage of late rice with a rate of 24.1 or 32.2 or 40.5 mg m^-2 h^-1 in no-tillage area with duck and no-tillage area without duck and conventional-tillage area without duck, respectively. The inhibition of methane emission was apparently effective in the rice-duck ecological system during the initial tillering stage and the full tillering stage. Compared to the no-tillage area without duck, methane emission decreased by 2.333 g m^-2. Compared to the conventional-tillage area without duck, methane emission decreased by 4.723 g m^-2. During the production period of late rice, the amount of methane emission in no-tillage area with duck was 3.373 g m^-2 lesser than that of no-tillage area without duck, and 5.59 g m^-2 less than that of conventional-tillage without duck area. The economic significance was analyzed. Farmers adopting the rice-duck ecological system obtained 2 166 and 4 207 RMB yuan ha^-1 more income than those who adopted a no-tillage without duck technique or conventional-tillage without duck technique, respectively. In addition to the reduction of the environmental pollution by methane emission, the farmers who adopted the rice-duck ecological system achieved economic benefits of 5 000 RMB yuan ha^-1, which was 2 206 and 4 274 RMB yuan ha^-1 more than those who adopted a no-tillage without duck technique and a conventional-tillage without duck technique, respectively. The rice-duck ecological system not only increased the economic benefits for farmers, but also reduced methane emission in rice paddy field. A sustainable agricultural production mode was formed. 展开更多
关键词 NO-TILLAGE late rice rice-duck system methane emission mitigation options economic evaluation
下载PDF
Methane and Nitrous Oxide Emissions from Rice-Duck and Rice-Fish Complex Ecosystems and the Evaluation of Their Economic Significance 被引量:13
8
作者 YUAN Wei-ling CAO Cou-gui LI Cheng-fang ZHAN Ming CAI Ming-li WANG Jin-ping 《Agricultural Sciences in China》 CAS CSCD 2009年第10期1246-1255,共10页
Rice-duck (RD) and rice-fish (RF) ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane (CH4) and nitrous oxide (N2O) emissions and thei... Rice-duck (RD) and rice-fish (RF) ecological systems are major complex planting and breeding models of rice paddy fields in southern China. Studying the methane (CH4) and nitrous oxide (N2O) emissions and their economic value from these two ecosystems can provide theoretical and practical basis for further development and utilization of these classical agricultural techniques. CH4 and N2O emissions from RD and RF ecological systems were measured in situ by using static chambers technique. Using global warming potentials (GWPs), we assessed the greenhouse effect of CH4 and N2O and their economic value. Results showed that the peaks of CH4 emission fluxes from RD and RF appeared at full tillering stage and at heading stage, and the average emission fluxes were significantly (P〈 0.05) lower than that from CK. N2O fluxes remained low when the field is flooded and high after draining the water. Compared with CK, the total amount of N2O emissions was significantly (P〈0.05) higher and slightly lower than those from RD and RF, respectively. In 2006 and 2007, the total greenhouse effect of CH4 and N20 from RD and RF were 4 728.3 and 4 611 kg CO2 ha^-1, 4 545 and 4 754.3 kg CO2 ha^-1, respectively. The costs of greenhouse effect were 970.89 and 946.81 RMB yuan ha^-1, and 933.25 and 976.23 RMB yuan ha^-1, respectively, which were significant lower than those from CK (5 997.6 and 5 391.5 RMB yuan ha^-1). Except for the environment cost of CH4 and N2O, the economic benefits from RD and RF were 2 210.64 and 4 881.92 RMB yuan ha^-1; 3 798.37 and 5 310.64 RMB yuan ha^-1, respectively, higher than those from CK. Therefore, RD and RF complex ecological planting and breeding models can effectively decrease and control CH4 and N2O emissions, and they are two of the effective strategies to reduce greenhouse gases from rice paddy fields and contribute in alleviating global warming. Thus, their adoption is important to the environment together with their economy benefits. 展开更多
关键词 methane emission nitrous oxide emission rice-duck complex ecosystem rice-fish complex ecosystem greenhouse effect economic benefit
下载PDF
SiO_2 AS HETEROGENEOUS NUCLEI OF INTERGROWTH EUTECTIC IN MODIFIED AS-CAST MEDIUM MANGANESE STEEL 被引量:1
9
作者 JIANG Qichuan YAN Jiulin +3 位作者 GUAN Qingfeng WANG Shoushi RONG Fujie LI Zhang Jilin University of Technology,Changchun,China 130025,China associate professor,Jilin University of Technology,Changchun 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1993年第8期156-160,共5页
By calculation of thermodynamics,analysis of crystal structure and study of TEM and eletron probe,it is first discovered that SiO2 can be acted as one of the heterogeneous nu- clei for lamellar intergorowth eutectic(a... By calculation of thermodynamics,analysis of crystal structure and study of TEM and eletron probe,it is first discovered that SiO2 can be acted as one of the heterogeneous nu- clei for lamellar intergorowth eutectic(austenite and cementite)crystallizing in modified as-cast medium manganese steel. 展开更多
关键词 SiO_2 heterogeneous necleus intergrowth eutectic medium manganese steel
下载PDF
Crossed intergrowth triggered TS-2 microsphere:Formation mechanism,modification and catalytic performance 被引量:2
10
作者 Hao Xu Wenwen Tian +5 位作者 Liping Xu Xin Jin Teng Xue Li Chen Mingyuan He Peng Wu 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1109-1117,共9页
TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,t... TS-2 microspheres,consisting of intergrown primary nanocrystals,was prepared by controlling the synthetic parameters.The effects of the amount of quaternary ammonium cations as structure-directing agent,H2O/Si ratio,the presence of alcohol and the temperature were carefully investigated on the crystallization process.The high alkalinity was proved to be highly important for the preservation of the microsphere morphology initially formed,due to the unique intergrown stacking style.An alkali treatment with the aqueous solution of structure-directing agent,organic amine and ammonium salt and subsequent Na+ion-exchange were performed to enhance the catalytic activity of TS-2 microsphere in the cyclohexanone ammoximation reactions,with both the conversion and selectivity higher than 99%.In the continuous reaction,the TS-2 microspheres exhibited to be durable catalyst with potential application in industrial ammoximation processes. 展开更多
关键词 TITANOSILICATE TS-2 microsphere Crossed intergrowth Ammoximation reaction POST-TREATMENT
下载PDF
Chalcopyrite Intergrowths in Sphalerite in the Meixian Lead-Zinc Deposit, Fujian Province and Their Metallogenic Significance 被引量:7
11
作者 顾连兴 周兵 张文兰 《Chinese Journal Of Geochemistry》 EI CAS 1998年第4期311-319,共9页
Ore textures and electron microprobe analyses show that in addition to highly scattered blebs in sphalerite grains, intergrown chalcopyrite also occurs as reds, myrrmekites andlamellae aligned along cleavages and twin... Ore textures and electron microprobe analyses show that in addition to highly scattered blebs in sphalerite grains, intergrown chalcopyrite also occurs as reds, myrrmekites andlamellae aligned along cleavages and twin boundaries of the host sphalerite. The majority of theintergrowths could have been formed by replacement of sphalerite by chalcopyrite, albeit part ofthem may have resulted from exsolution. Not only copper, but also iron were introduced intothe sphalerite by replacive fluids.While the front of the replacing fluid was moving forward through a sulphide orebody, Znand Pb were dissolved and Cu was precipitated, resulting in zonal refining of the sulphide ores.The remobilized zinc and lead were precipitated at favourable sites with changed physiccrchemical conditions. This is a Possible mechanism for the formation of copper-poor zinc and lead oresabove or lateral to the copper orebodies in some of the massive sulphide deceits reworked andoverprinted by late-stage granites and their hydrothermal fluids. 展开更多
关键词 闪锌矿 黄铜矿 硫化物矿床 共生矿床 福建 锌矿床 找矿标志
下载PDF
Perpendicular intergrowth ZSM-5 plates with shortened 10-MR pores 被引量:2
12
作者 Ensheng Zhan Zhiping Xiong +4 位作者 Yan Zhou Mingrun Li Pengfei Wang Weibin Fan Wenjie Shen 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2020年第7期1132-1139,共8页
ZSM-5 plates with a perpendicular intergrowth structure was synthesized by using a simple amine as the structure directing agent under hydrothermal conditions,in which the mother plate and the perpendicularly standing... ZSM-5 plates with a perpendicular intergrowth structure was synthesized by using a simple amine as the structure directing agent under hydrothermal conditions,in which the mother plate and the perpendicularly standing plates oriented along the(010)and(100)planes of MFI crystals,respectively.During the crystallization process,the mother plate was initially formed on the surface of the amorphous solid gel,while a set of parallel plates perpendicularly grew on its surface,via a homogeneous nucleation mechanism.The mother plate and the perpendicular plates had a similar thickness of 100-200 nm and were characterized by considerably shortened straight and zigzag 10 member ring pores,respectively.This unique intergrowth structure greatly facilitated the diffusion of the reactive molecules in HZSM-5 crystals during methanol conversion to hydrocarbons. 展开更多
关键词 ZSM-5 Plate structure Perpendicular intergrowth Channel length Hierarchical structure Molecule diffusion
下载PDF
Dynamic Emission of CH<sub>4</sub>from a Rice-Duck Farming Ecosystem 被引量:1
13
作者 Jia-En Zhang Ying Ouyang +1 位作者 Zhao-Xiang Huang Guo-Ming Quan 《Journal of Environmental Protection》 2011年第5期537-544,共8页
Global climatic change induced by emissions of greenhouse gases from human activities is an issue of increasing in-ternational environmental concerns, and agricultural practices and managements are the important contr... Global climatic change induced by emissions of greenhouse gases from human activities is an issue of increasing in-ternational environmental concerns, and agricultural practices and managements are the important contributors for such emissions. This study investigated dynamic emission of methane (CH4) from a paddy field in a rice-duck farming ecosystem. Three different cultivation treatments, namely the organic fertilizer + duck (OF+D), chemical fertilizer + duck (CF + D), and chemical fertilizer (Control) treatments, were employed in this study. Experimental data showed that hourly variations of CH4 emission from the paddy field during the day were somewhat positively correlated (R2 = 0.7 for the OF + D treatment and R2 = 0.6 for the CF+D treatment) to the hourly changes in air temperatures in addi-tion to the influences of the duck activities. The rate of CH4 emission for the CF+D treatment was higher than that of the Control treatment at the tillering stage, whereas the opposite was true at the heading stage. In contrary, the rate of CH4 emission for the OF + D treatment was always higher than that of the Control treatment regardless the tillering or heading stage. Our study revealed that the rate of CH4 emission depended not only on air temperature but also on the rice growth stage. A 6.7% increase in CH4 emission and in global warming potential (GWP) was observed for the CF + D treatment as compared to the Control treatment. This study suggested that although the impacts of duckling on the emission of CH4 depended on the rice growth stage and air temperature regime, the introduction of ducks into the rice farming system in general mitigated the overall CH4 emission and thereby the GWP. 展开更多
关键词 Methane EMISSION Global WARMING Potential rice-duck FARMING
下载PDF
Syntactic Intergrowth Structure in the Calcium-Rare Earth Fluorocarbonate Minerals
14
作者 吴秀玲 孟大维 +4 位作者 杨光明 潘兆橹 李斗星 戴吉岩 胡魁毅 《Journal of Rare Earths》 SCIE EI CAS CSCD 1998年第3期39-44,共6页
The microstructural characteristics of syntactic polycrystal in the calcium rare earth fluorocarbonate minerals from Southwest China have been studied by means of selected area electron diffraction and high resolutio... The microstructural characteristics of syntactic polycrystal in the calcium rare earth fluorocarbonate minerals from Southwest China have been studied by means of selected area electron diffraction and high resolution electron microscopy(HREM). The complication of the heterogeneous fabric of the minerals have been revealed by HREM. The results show that the crystal structure of the minerals was formed by a disorder stacking of the unit layers of bast naesite and synchisite in the calcium rare earth fluorocarbonate minerals along c direction. The stacking fault and other crystal defects in the syntactic polycrystal have been discussed. 展开更多
关键词 Rare earths Calcium rare earth fluorocarbonate mineral Syntactic intergrowth High resolution electron microscopy
下载PDF
High Yield and Efficient Cultivation Techniques of Rice under Rice- fish Intergrowth Model in Chengdu
15
作者 Liangyu LI Shun HE +6 位作者 Hong TANG Xia CHEN Ma YANG Xiaoli ZHANG Jian CHEN Jiaxing LIU WenyanWEI 《Asian Agricultural Research》 2018年第3期76-77,共2页
The integrated planting and breeding of paddy fields is a kind of eco-planting and breeding mode which makes rice and aquatic animals benefit from each other,greatly reducing the harm of rice pests and diseases,using ... The integrated planting and breeding of paddy fields is a kind of eco-planting and breeding mode which makes rice and aquatic animals benefit from each other,greatly reducing the harm of rice pests and diseases,using less or even no fertilizers or pesticides,greatly reducing the agricultural non-point source pollution,thus achieving the " multiple use of water,multiple harvests in one field,grain and fishing winwin,ecological and high efficient use. " In this paper,the high yield and efficient cultivation techniques of rice under the rice-fish intergrowth model in Chengdu was introduced from the aspects of selecting good paddy fields for fishing,using appropriate rice varieties,soaking disinfection,timely sowing and nurturing strong seedlings,reasonable close planting,reasonable fertilization,scientific water management,scientific pest control and rice harvests. 展开更多
关键词 Rice-fish intergrowth model RICE High yield and high efficiency cultivation techniques Chengdu area
下载PDF
贵州织金互层型磷块岩工艺矿物学及浮选试验研究
16
作者 蒋权 杨勇 朴海善 《有色金属(选矿部分)》 CAS 2024年第2期1-8,共8页
对贵州织金地区中低品位磷块岩进行工艺矿物学研究,查明了矿石的矿物组成、化学组成、嵌布特征、矿物粒度分布等。结果表明,矿石中主要有用矿物是氟磷灰石,脉石矿物主要是石英,氟磷灰石含量为57.62%,白云石含量为25.34%,还含有少量的石... 对贵州织金地区中低品位磷块岩进行工艺矿物学研究,查明了矿石的矿物组成、化学组成、嵌布特征、矿物粒度分布等。结果表明,矿石中主要有用矿物是氟磷灰石,脉石矿物主要是石英,氟磷灰石含量为57.62%,白云石含量为25.34%,还含有少量的石英、黄铁矿、方解石等。氟磷灰石与白云石、石英的嵌布关系紧密,连生关系以三连生以上为主,嵌布关系复杂。利用工艺矿物学参数自动分析系统(BPMA)、X射线衍射(XRD)、X射线荧光光谱仪(XRF)等分析手段并结合相关数据,确定了采用二段式反浮选脱镁工艺流程,可以获得P_(2)O_(5)品位为32.40%、P_(2)O_(5)回收率为85.13%的磷精矿,MgO含量由12.50%降至1.60%,选矿指标较为理想,为该地区磷矿的开发和利用提供了一定的技术依据。 展开更多
关键词 磷块岩 工艺矿物学 粒度分布 连生关系
下载PDF
超导磁选白云鄂博尾矿稀土颗粒捕获及聚集行为
17
作者 刘昕旸 白庆伟 +3 位作者 赵增武 许鹏 贺宇龙 贾艳 《有色金属(选矿部分)》 CAS 2024年第4期144-153,共10页
超导磁分离技术中,稀土矿物颗粒在磁介质上的聚集半径与磁介质填充率应相互匹配,以确保高效的矿物分离效果和提高稀土尾矿资源利用率。基于颗粒轨迹模型,探究了矿浆流速对颗粒捕获的影响并建立了颗粒饱和聚集模型,以计算稀土矿物颗粒单... 超导磁分离技术中,稀土矿物颗粒在磁介质上的聚集半径与磁介质填充率应相互匹配,以确保高效的矿物分离效果和提高稀土尾矿资源利用率。基于颗粒轨迹模型,探究了矿浆流速对颗粒捕获的影响并建立了颗粒饱和聚集模型,以计算稀土矿物颗粒单体及其连生体在磁介质上的饱和聚集半径、聚集半径和磁介质间距关系,从而优化磁介质填充率。并通过颗粒沉积试验,验证了聚集模型的正确性。研究结果表明,矿浆流动速度最优为0.1m/s时有效去除了杂质萤石矿物。磁介质有一个临界填充率,高于临界填充率不会发生堵塞。随着磁介质直径的增加,颗粒饱和聚集半径rBa和磁介质临界填充率逐渐增大,当连生体度为1/20的稀土连生体与磁介质直径为0.06mm时,临界填充率为5.6%。当磁介质直径为0.4mm时临界填充率为20.6%。本研究结果为稀土矿物的高效分离提供了重要的理论基础,也为工业生产中磁分离技术的优化与设计提供了可靠的参考依据。 展开更多
关键词 磁介质 超导磁分离 稀土颗粒 连生体 颗粒聚集
下载PDF
The occurrence of metallic copper and redistribution of copper in the shocked Suizhou L6 chondrite
18
作者 Xiande Xie Xiangping Gu Yiping Yang 《Acta Geochimica》 EI CAS CSCD 2024年第5期827-837,共11页
Copper possesses very strong chacophile properties,but under the conditions found in meteorites,its behavior is like that of siderophile elements.The Suizhou meteorite is a highly shocked L6 chondrite.Troilite and tae... Copper possesses very strong chacophile properties,but under the conditions found in meteorites,its behavior is like that of siderophile elements.The Suizhou meteorite is a highly shocked L6 chondrite.Troilite and taenite are considered the main primary carrier of copper in this meteorite,and the post-shock thermal episode is considered the main reason that elemental Cu migrates from its original host phase and forms metallic grains.The Suizhou meteorite contains a few very thin shock melt veins.The occurrence and behavior of metallic copper in this meteorite were studied by optical microscopic examination,electron microprobe analyses,and high-resolution X-ray elemental intensity mapping.Our results show that metallic copper is abundant in the Suizhou chondritic rock.Metallic copper grains adjacent to small troilite grains inside FeNi metal are the most common occurrence,and those at the FeNi metal–troilite interface are the second most common case.The metallic copper grains occurring at the interface of FeNi metal/troililte and silicate are rather rare.Metallic copper grains are not observed within the Suizhou shock veins,Instead,Cu in elemental form is transferred through shock metamorphism into FeNi metal+troilite intergrowths.Four diff erent occurrence types of Cu in the FeNi metal+troilite intergrowths have been identifi ed:the concentrations of Cu in the FeNi+FeS intergrowths for four occurrence types are rather close,we estimate it might be lower than 1 wt%. 展开更多
关键词 Suizhou chondrite Shock vein Metallic copper Metal-troilite intergrowth Elemental intensity mapping
下载PDF
不同树种附生栽培铁皮石斛试验
19
作者 陈国德 吴二焕 +2 位作者 陈彧 饶丹丹 韩豫 《热带农业科学》 2024年第7期53-57,共5页
以铁皮石斛(Dendrobium officinale Kimura et Migo)为实验材料,探索不同树种附生栽培对铁皮石斛的影响。结果表明:附生沉香处理能显著提高铁皮石斛的各项生长指标;附生花梨有助于提高铁皮石斛中总黄酮和粗纤维含量,附生橡胶和荔枝能显... 以铁皮石斛(Dendrobium officinale Kimura et Migo)为实验材料,探索不同树种附生栽培对铁皮石斛的影响。结果表明:附生沉香处理能显著提高铁皮石斛的各项生长指标;附生花梨有助于提高铁皮石斛中总黄酮和粗纤维含量,附生橡胶和荔枝能显著提高铁皮石斛的醇浸出物;通过隶属函数法综合评价发现,附生于沉香树上对铁皮石斛生长与品质综合促进效果最佳,综合得分0.70。 展开更多
关键词 铁皮石斛 栽培 附生 综合评价
下载PDF
高频层序划分揭示断陷深湖层系源储共生发育规律——以北部湾盆地海中凹陷始新统流沙港组二段为例
20
作者 江东辉 《西北大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第3期527-540,共14页
以北部湾盆地海中凹陷始新统流沙港组二段断陷湖盆深湖沉积体系为例,以高分辨率层序地层学理论为指导,利用最大熵谱分析与小波变换分析技术对流二段进行高频层序划分,在对沉积体系发育规律分析的基础上,通过流二段各五级层序深湖相烃源... 以北部湾盆地海中凹陷始新统流沙港组二段断陷湖盆深湖沉积体系为例,以高分辨率层序地层学理论为指导,利用最大熵谱分析与小波变换分析技术对流二段进行高频层序划分,在对沉积体系发育规律分析的基础上,通过流二段各五级层序深湖相烃源岩及湖底扇重力流相砂岩发育规律的分析,探讨断陷湖盆深湖层系源储共生的发育规律。研究认为:INPEFA频谱分析与小波变换分析技术可有效地运用于断陷湖盆深湖层系高频层序划分;北部湾盆地海中凹陷深湖层系流沙港组二段可划分为1个三级层序、2个四级层序、5个五级层序,其中2个四级层序以最大湖泛面为界分为湖泊扩张体系域(TST)与湖泊收缩体系域(HST);断陷湖盆优质厚层烃源岩往往发育于湖泊扩张体系域四级层序下部初始湖泛面(Ts)的五级层序内,虽然湖泊扩张体系域四级层序顶部最大湖泛面(Mfs)上下紧邻的五级层序发育的烃源岩面积大,但厚度小,为次要烃源岩及良好的盖层;湖泊扩张体系域四级层序中部的五级层序往往发育湖底扇重力流相储层,其夹持发育于初始湖泛面及最大湖泛面附近的两套烃源岩之间,可共同组成良好的“三明治”式生储盖组合,该套“三明治”式生储盖组合应是下一步非常规油气勘探的重要区域。 展开更多
关键词 高频层序 深湖层系 源储共生规律 北部湾盆地 海中凹陷 流沙港组二段
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部