期刊文献+
共找到14,500篇文章
< 1 2 250 >
每页显示 20 50 100
Determination of Organic Matter and Trace Metals Elements (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) in the Soils of the Banks of Watercourses in Brazzaville City (Republic of Congo)
1
作者 Mbianda Nfong-Ya Orline Lesley Nzila Jean de Dieu +5 位作者 Louzayadio Mvouezolo Raison Félicien Bonazaba Milandou Longin Justin Clair Nguelet-Moukaha Isidore Wando Georgy Patience Ouamba Jean Maurille Aina Martin Pépin 《Open Journal of Soil Science》 2025年第2期156-172,共17页
This work focused on determining the physico-chemical characteristics (pH, carbon and nitrogen) and trace metal elements (TMEs) content (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) of soils in the Brazzaville city. Soil samples w... This work focused on determining the physico-chemical characteristics (pH, carbon and nitrogen) and trace metal elements (TMEs) content (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) of soils in the Brazzaville city. Soil samples were taken from a depth of 0 to 20 cm using a hand auger on both banks of five tributaries of the Congo River (Djoué, Mfilou, Mfoa, Tsiémé, Djiri) that flow through the city of Brazzaville. 90 sampling points were defined, with 3 points 250 m apart on the banks and located, for each river, at three sites: upstream, midstream and downstream. Finally, 15 composite samples representative of the study area were taken. The average pH values of the water varied between 6.5 and 7.5. These pH values show that the soils studied are neutral. Total carbon content varied between 0.7% (Djiri) and 1.6% (Djoué). Total nitrogen content ranged from 0.08% (Djiri) to 0.12% (Djoué). TMEs contents varied from 0.5 to 1.8 mg/kg for Sb, from 0.5 to 2.5 mg/kg for As, from 0.1 to 0.18 mg/kg for Cd, from 4.2 to 11.3 mg/kg for Cr, from 0.07 to 0.27 mg/kg for Hg, from 0.7 to 2.4 mg/kg for Ni, from 0 to 158 mg/kg for Pb and from 16 to 105 mg/kg for Zn. The lowest TMEs levels were observed in the soils of the Djiri river, while the highest levels were observed in the soils of the Djoué and Tsiémé rivers. The ANOVA and Bonferroni test did not show significant differences in the means of the parameters measured (p > 0.05). The TMEs levels were below the accepted standards (NF U44-041), with the exception of Pb, which had high levels downstream of the Djoué. According to the pollution index values calculated using soil TME content, the soils on the banks of the Djoué river are considered polluted, while those on the banks of the Tsiémé river are moderately polluted, those on the banks of the Mfoa and Mfilou rivers are slightly polluted, and the soils on the banks of Djiri river are unpolluted. 展开更多
关键词 Carbon Nitrogen trace Metal elements Soil BRAZZAVILLE CONGO
在线阅读 下载PDF
Trace Element Concentrations in the Sera of Pregnant Women in Kisangani, Democratic Republic of Congo
2
作者 Likilo Osundja Jérémie Komanda Likwekwe Emmanuel +3 位作者 Tshodi Bulanda Arsène Juakali Sihalikyolo Jean-Jeannot Buhendwa Mirindi Victor Katenga Bosunga Gédéon 《Journal of Biosciences and Medicines》 2025年第2期218-229,共12页
Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intak... Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intake fails to compensate. The aim of this research is to determine the status of trace elements (calcium, copper, magnesium, selenium and zinc) in pregnant women in the city of Kisangani. Methods: We carried out an analytical cross-sectional study of non-pregnant and pregnant women living in Kisangani, from 05 October 2023 to 05 January 2024. Concentrations of trace elements in sera were analysed using an inductively coupled plasma mass spectrophotometer (ICP-MS Agilent 7700X). Statistical analysis of the data was performed using R software version 4.3.0. Results: The mean age was 26.3 ± 6.7 years;the mean copper and magnesium levels in the serum of pregnant women were 12.58 ± 1.13 micromol/l and 1.03 ± 1.03 mmol/l respectively. The medians for calcium and zinc were 1.49 mmol/l and 8.42 micromol/l. The selenium mode was 0.41 micromol/l. Variations in trace element levels in sera of pregnant women were 0.94 - 2.22 mmol/l for calcium;0.31 - 0.78 micromol/l for selenium;and 7.29 - 12.72 micromol/l for zinc;11.04 - 14.99 micromol/l for copper, and 0.082 - 1.05 mmol/l for magnesium. Conclusion: Serum trace element concentrations in pregnant women were lower than those observed in non-pregnant women. Trace element reserves in pregnant women depended on their nutrient status prior to pregnancy, hence, there was an urgent need for trace element balance prior to pregnancy. 展开更多
关键词 trace element Zinc Copper SELENIUM CALCIUM Magnesium Pregnant Woman SERUM Kisangani
在线阅读 下载PDF
Magmatic to Hydrothermal Evolution of Bianjiadayuan Ag-Pb-Zn-Sn Deposit,Northeast China:A Quartz Texture and Trace Elements Study
3
作者 Xin Wang Nan Qi +3 位作者 Xinyou Zhu Xi-Heng He Haowei Gu Xiaohua Deng 《Journal of Earth Science》 2025年第4期1493-1504,共12页
Quartz trace elements are extensively employed in studying magmatic evolution,fluid evolution,and metal enrichment.The Bianjiadayuan Ag-Pb-Zn-Sn deposit is a typical magmatichydrothermal system in northeastern China,h... Quartz trace elements are extensively employed in studying magmatic evolution,fluid evolution,and metal enrichment.The Bianjiadayuan Ag-Pb-Zn-Sn deposit is a typical magmatichydrothermal system in northeastern China,however,studies on its complex magmatic-hydrothermal evolution are limited.This study investigates the quartz from the Bianjiadayuan deposit to gain insight into the physicochemical evolution of mineralization using cathodoluminescence(CL)textures and laser ablation-inductively coupled plasma-mass spectrometry(LA-ICP-MS)of quartz.Five types quartz(Q1 to Q5)were identified.From Q1 in quartz porphyry to Q5 in Ag-Pb-Zn veins,the CL intensity and Ti content gradually decreases,and Ge,Ge/Ti,and Al/Ti ratios increase,indicating a temperature decline from magmatic to hydrothermal stages.The Sb content shows an opposite trend to Ti content,correlating positively with Ge content in quartz,suggesting that Sb content could also be temperature-dependent.These trace elements in quartz indicate cooling is critical for Ag mineralization.Furthermore,quartz phenocryst(Q1)from the quartz porphyry shows low Al/Ti(mostly<4)and Ge/Ti ratios(<0.04),suggesting a low degree of magmatic evolution.The Sb content in Q5 from Ag-Pb-Zn-quartz veins(>1 ppm,mostly tens of ppm)is notably higher compared to quartz in other lithologies including Sn-bearing quartz veins(<1 ppm),suggesting that Sb contents can serve as an effective indicator of Ag mineralization. 展开更多
关键词 QUARTZ trace elements Ag mineralization Ag-Pb-Zn-Sn deposit Bianjiadayuan
原文传递
Trace Elements and Tumor: Research Progress
4
作者 Zhiguang Wen Cailing Wei Siwu Fu 《Proceedings of Anticancer Research》 2025年第6期1-9,共9页
This review systematically summarizes the core advances in the field of trace elements and tumors,and clarifies the dual roles of key elements such as Zn,Cu,Fe,Se,Mn,and Ni in tumorigenesis(e.g.,DNA damage repair),tum... This review systematically summarizes the core advances in the field of trace elements and tumors,and clarifies the dual roles of key elements such as Zn,Cu,Fe,Se,Mn,and Ni in tumorigenesis(e.g.,DNA damage repair),tumor progression(e.g.,tumor microenvironment regulation),and therapeutic response-these elements not only possess tumor-suppressive potential but can also contribute to tumorigenesis.Meanwhile,it confirms the breakthrough value of multi-omics technologies and organoid models in deciphering the“element-cell-tumor”interaction mechanisms,which overcomes the limitations of traditional in vitro experiments and also points out the core directions for subsequent clinical research. 展开更多
关键词 TUMOR trace elements TREATMENT
暂未订购
Major-and Trace-Element Chemistry of Clinopyroxene and Amphibole from High-Mg Diorite in Chelyabinsk Massif(Urals):Insights into Petrogenesis and Magma Source Constraints
5
作者 Tatiana Osipova Gennadiy Kallistov +1 位作者 Maria Chervyakovskaya Vasiliy Chervyakovskiy 《Journal of Earth Science》 2025年第2期508-523,共16页
Field-and petrographic investigations,together with microanalytical major-and traceelement studies,were carried out on clinopyroxene and amphibole from high-Mg diorite in the subduction-related Chelyabinsk granitic ma... Field-and petrographic investigations,together with microanalytical major-and traceelement studies,were carried out on clinopyroxene and amphibole from high-Mg diorite in the subduction-related Chelyabinsk granitic massif to understand its petrogenesis and source.The clinopyroxene composition(high Mg#,Cr-content,sum of REE and Ti/Eu ratio;depletion in HREE;negative Eu-anomaly)indicates that it formed from a reduced melt derived from a mantle source metasomatized by fluids/melts having crustal affinity.Melt compositions in equilibrium with clinopyroxene and amphibole were calculated using solid/liquid partition coefficients.The high Nb/Y and Zr/Y ratio values of a liquid simulated from clinopyroxene,which appears to have very similar characteristics to sanukitoid melts,indicate a low degree of melting of the mantle source.Melt simulated from amphibole is more evolved and more felsic(dacitic).It displays a geochemical“amphibole fractionation”signature,indicating the peritectic transformation of clinopyroxene to amphibole in the lower crust.Rock textures and major element mineral compositions suggest that further amphibole was precipitated directly from the melt in the middle crust.The results show that the Chelyabinsk highMg diorite was probably formed as a cumulate from sanukitoid-like melt during its ascent and cooling below dacitic liquidus inside the amphibole stability field. 展开更多
关键词 high-Mg diorite CLINOPYROXENE amphibole trace elements cumulus mineral SANUKITOID URALS geochemistry
原文传递
Assessment of trace elements distribution and sources from snowpits in the Lambert Glacier region,coastal East Antarctica
6
作者 Yalalt Nyamgerel Soon Do Hur +3 位作者 Tseren-Ochir Soyol-Erdene Cunde Xiao Hyejung Jung Jeonghoon Lee 《Geoscience Frontiers》 2025年第3期425-437,共13页
The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,partic... The measurement of trace elements in Antarctic snow is crucial for understanding historical atmospheric geochemical changes and circulation patterns.However,studies on their spatial distributions remain limited,particularly those evaluating multiple metals across several snowpits,making interpretation challenging.This study investigates the distributions and sources of trace elements-including Cd,Ba,Pb,U,Bi,V,Mn,Fe,Cu,Zn,and As-across four snowpits in the Lambert Glacier Basin,East Antarctica.The trace elements exhibit site-,element-,and season-dependent variations,with higher concentrations observed at inland sites.In contrast,δ^(18)O and ion concentrations decrease with increasing distance from the coast and elevation,underscoring the influence of marine emissions.Crustal sources primarily contributed to Ba,U,V,Mn,and Fe,while non-crustal sources predominantly contributed to Cd,Bi,Zn,Pb,Cu,and As.Positive matrix factorization(PMF)analysis indicates that trace element concentrations in Pits 2 and 3 are influenced by both crustal and non-crustal sources,while Pit 4 reflects a mixed-source influence.Pit 1(coastal site)also indicates the mixed sources with influence of a highly dynamic marine climate and environment.The PMF results reveal similarities in emission sources and atmospheric transport patterns across the snowpits,facilitating a more comprehensive interpretation of longer ice core records.Overall,this study provides valuable insights into trace element distributions and enhances our understanding of past environmental and climatic conditions. 展开更多
关键词 trace elements Spatial variation ANTARCTICA Lambert Glacier Basin Positive matrix factorization
暂未订购
Miocene Pb-Zn Mineralization in the Eastern Gangdese Metallogenic Belt:Evidence from in situ Rb-Sr Dating of Mica and Trace Element Geochemistry of Sphalerite
7
作者 ZHAO Xiaoyan YANG Zhusen +2 位作者 LIU Chang DONG Yanrui SHI Haiyan 《Acta Geologica Sinica(English Edition)》 2025年第3期806-821,共16页
Four Pb-Zn deposits,namely Bangpu(BP),Digei(DG),Nabuding(NB)and Cuoga(CG),are located within a 20 km distance of each other in the Gangdese porphyry copper belt(GPCB).The age and nature of the Pb-Zn mineralization,esp... Four Pb-Zn deposits,namely Bangpu(BP),Digei(DG),Nabuding(NB)and Cuoga(CG),are located within a 20 km distance of each other in the Gangdese porphyry copper belt(GPCB).The age and nature of the Pb-Zn mineralization,especially its relationship to magmatism,remain uncertain.In order to address this issue,mica from the four deposits was selected for in situ Rb-Sr dating,with sphalerite additionally being selected for in situ trace element analysis.Detailed geological research has revealed that the BP and NB deposits are primarily skarn-type Pb-Zn mineralization,while DG and CG are associated with magmatic hydrothermal breccia and are characterized by banded-type mineralization.The Rb-Sr isochron ages of syn-mineralization muscovite at the BP and CG deposits are 11±6 Ma and 19.7±0.7 Ma respectively.Fe,Cd,In,Mn and Sn occur as lattice substitutions in sphalerite from the four deposits.Cu exists as microinclusions in BP,but occurs isomorphically in the DG,NB and CG deposits.The formation temperatures of the four deposits,as calculated from sphalerite geothermometry,range from approximately 200℃to 300℃,indicating that they belong to medium temperature deposits.BP and NB are classified as skarn Pb-Zn deposits,while DG and CG are categorized as hydrothermal filled Pb-Zn deposits.These results suggest that,in addition to porphyry Cu mineralization,the GPCB also contains significant Miocene Pb-Zn mineralization. 展开更多
关键词 in situ Rb-Sr dating trace elements SPHALERITE Pb-Zn deposit Gangdese porphyry copper belt
在线阅读 下载PDF
Effects of combined preconception and prenatal myo-inositol, probiotics, and trace element supplementation on the outcomes of depressed mothers
8
作者 Shu-Fang Qi Hong-Xia Sun Jie Zhao 《World Journal of Psychiatry》 2025年第7期91-102,共12页
BACKGROUND Perinatal depression affects 10%-20%of pregnant women and subsequently influences maternal health and fetal development.Concerns over the safety of antidepressants during pregnancy have prompted the explora... BACKGROUND Perinatal depression affects 10%-20%of pregnant women and subsequently influences maternal health and fetal development.Concerns over the safety of antidepressants during pregnancy have prompted the exploration of nutritional interventions as adjunct therapies.This study evaluated the impact of combining preconception and prenatal supplementation with myo-inositol,probiotics,and trace elements on mood,quality of life,and fetal development in depressed mothers.This retrospective cohort study included 314 pregnant women who were diag-nosed with mild to moderate depression,as determined by a Zung self-rating depression scale score of less than 69.The participants were divided into an intervention group(n=161)receiving myo-inositol,probiotics,and trace elements and a control group(n=153)without supplementation.Supplementation comm-enced 3 months before conception and continued through pregnancy.Psychiatric symptoms and quality of life were evaluated using the positive and negative affect schedule-now,state-trait anxiety inventory,Patient Health Ques-tionnaire-8,and World Health Organization Quality of life Assessment:Brief Version scales preconception and postpartum.Fetal development metrics were assessed via ultrasound,and neonatal outcomes were recorded.RESULTS The intervention group presented significant reductions in gestational diabetes mellitus(13.04%vs 23.53%,P=0.016)and gestational hypertension(3.73%vs 9.15%,P=0.049).Higher levels of inositol,iron,zinc,and probiotics were observed near term in the intervention group.Postpartum mood assessments indicated lower anxiety and depression scores for the intervention group,with significant improvements in the positive and negative affect schedule-now(P=0.002),trait anxiety(P=0.002),and Patient Health Questionnaire-8(P=0.018)scores.The World Health Organization Quality of life Assessment:Brief Version scores improved in the psychological(P=0.041)and environmental(P=0.009)domains postpartum.Fetal biparietal diameter and femoral length were greater in the intervention group alongside better neonatal body length and reduced neonatal unit admissions(2.48%vs 7.84%,P=0.031).CONCLUSION Combined supplementation with myo-inositol,probiotics,and trace elements from preconception through pregnancy may reduce pregnancy-related complications,enhance mood and quality of life,and improve fetal growth metrics. 展开更多
关键词 nutritional interventions retrospective cohort study perinatal depression trace elements PRECONCEPTION PRENATAL preconception prenatal supplementation adjunct therapiesthis
暂未订购
Multiple-stage W mineralization in the Guanfang W deposit,southeastern Yunnan Province,China:Insights from scheelite in-situ trace elemental and Sr isotopic analyses
9
作者 Bin Sun Yi Liu +4 位作者 Zhigang Kong Xuelong Liu Xiaojun Jiang Chao Li Wenchang Li 《Acta Geochimica》 2025年第1期112-127,共16页
The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan,China.Despite extensive research,the fluid evolution process of the deposit remains ambigu... The Guanfang large-scale W deposit is located in the W polymetallic ore concentration area of Bozhushan in southeastern Yunnan,China.Despite extensive research,the fluid evolution process of the deposit remains ambiguous,leading to controversy regarding its genesis.This study conducted a detailed field geological survey,with systematic sampling of the KT6 orebody,to delineate mineralization stages.Fine mineralogy work,including the use of CL images of scheelite,in-situ LA-ICP-MS trace elements,and Sr isotopes,was carried out on diff erent generations of scheelite formed in various stages.The findings identified the evolution of fluids in the mineralization process,shedding light on the genesis of the deposit.The study revealed four mineralization stages at the Guanfang W deposit:prograde skarn stage,retrograde skarn stage,quartz-sulfide stage,and carbonate-fluorite stage.Diff erent generations of scheelite(Sch I,Sch II,Sch III)were observed in the first three stages,displaying distinct chondrite-normalized REE patterns.The REE of Sch I mainly substituted into the Ca site by REE^(3+)+□_(Ca),and there may be a similar substitution of Nb for REE,whereas it is not the main substitution method.The REE of Sch II mainly enter the scheelite lattice in the form of REE 3++Na+,and there may be a substitution of Nb for REE isomorphism.In the early stage,The REE of Sch III was mainly replaced by Nb for REE isomorphism,while in the later stage,the replacement mode of REE^(3+)+□_(Ca)coexisted with it.The Mo content in scheelite,along with the corresponding Eu anomalies in both scheelite and garnet,collectively imply that the ore-forming fluids during various mineralization stages were predominantly oxidizing,with only slight reducibility observed in Sch II.The in-situ Sr isotope ratios of scheelite concentrates ranged from 0.7093 to 0.7153,resembling those of the Bozhushan granite,indicating a relationship between W mineralization and granite.In addition,the Y/Ho ratios of scheelite from various mineralization stages exhibit a narrow range(19-31),with a pronounced correlation between the contents of Y and Ho and a similar trend in their variation.This consistency suggests that the Guanfang deposit has undergone a uniform or comparable evolutionary process,implying a stable ore-forming fluid across diff erent mineralization stages. 展开更多
关键词 Guanfang W deposit trace elements of scheelite In-situ Sr isotopes Southeast Yunnan
在线阅读 下载PDF
Effects of Organic and Medium and Trace Element Fertilizers on Yield and Quality of Panax notoginseng
10
作者 Yongquan ZHU Junwen CHEN +3 位作者 Guangqiang LONG Tongbin ZHU Shusheng ZHU Shengchao YANG 《Medicinal Plant》 CAS 2020年第3期55-59,共5页
[Objectives]This study aimed to investigate the effects of organic and medium and trace element fertilizers(Ca,Zn,B)on yield and quality of Panax notoginseng to provide theoretical support for rational fertilization i... [Objectives]This study aimed to investigate the effects of organic and medium and trace element fertilizers(Ca,Zn,B)on yield and quality of Panax notoginseng to provide theoretical support for rational fertilization in cultivation of P.notoginseng.[Methods]Five fertilization treatments,control(CK),organic fertilizer(OM),zinc fertilizer(ZF),boron fertilizer(BF)and lime(LF),were designed.A two-consecutive-year field plot trail was conducted.The biological traits,yield and saponin content of P.notoginseng were determined.[Results]The application of organic fertilizer had no significant effect on the biological traits of P.notoginseng.Trace element fertilizers significantly increased the scape length of P.notoginseng.Among the treatments,ZF significantly increased the single flower weight but reduced the inflorescence diameter,while the effects of BF were opposite to those of ZF;LF significantly increased the stem thickness and reduced the plant height.All treatments significantly increased the seedling rate of three-year-old P.notoginseng,and the increase in the LF group(20.49%)was the largest,followed by those in the ZF(16.80%)and OM(16.40%)groups,and the increase in the BF group(13.08%)was the smallest.Although OM,ZF and BF treatments caused the root weight of individual plants to decrease,the final yield of each treatment was higher than that of the control group,and the increases in the BF and LF groups exceeded 17%(P<0.05).The total saponin outputs of all the treatments except OM were significantly higher than that of the control group.[Conclusions]Under the conditions of this test,the supplementation of organic and medium and trace element fertilizers on the basis of conventional fertilization will help to increase the yield of P.notoginseng.However,the reduction of the total saponin output of P.notoginseng caused by organic fertilizer cannot be ignored. 展开更多
关键词 Panax notoginseng Organic fertilizer trace element fertilizer YIELD Total saponin output
在线阅读 下载PDF
Wavy Distribution of Trace Elements in Phytolacca Samples from Different Areas 被引量:4
11
作者 杜莹 欧阳荔 +1 位作者 刘雅琼 王京宇 《Journal of Chinese Pharmaceutical Sciences》 CAS 2004年第4期271-275,共5页
To study the distribution of 25 elements, i.e. Be, Cd, Ce, Cr, Cu, Dy, Er,Eu, Gd, Ge, Ho, La, Lu, Mo, Nd, Pb, Pr, Sm, Sr, Tb, Tl, Tm, Y, Yb and Zn in Phytolacca, atraditional Chinese medicinal herb, collected from nin... To study the distribution of 25 elements, i.e. Be, Cd, Ce, Cr, Cu, Dy, Er,Eu, Gd, Ge, Ho, La, Lu, Mo, Nd, Pb, Pr, Sm, Sr, Tb, Tl, Tm, Y, Yb and Zn in Phytolacca, atraditional Chinese medicinal herb, collected from nine areas of P. R. China. Methods Twenty-fiveelements in Phytolacca including essential elements, toxic elements and rare earth elements intraditional Chinese medicinal herbs from different areas were analyzed by ICP-MS. Results The 25elements in Phytolacca were determined by ICP-MS under optimized conditions. The detection limitswere 0.003 -0.71 ng·mL^(-1). The recoveries were 88% - 118% . The relative standard deviations ofthe measurements were 1.7% - 13.3%. Conclusion The determined concentrations of elements inPhytolacca acinosa Roxb vary from one area to another; however, the distribution tendency ofelements in all the samples is similar. The distribution tendency of rare earth elements inPhytolacca acinosa Roxb is consistent with that in nature. 展开更多
关键词 traditional chinese medicinal herbs trace elements ICP-MS DISTRIBUTION
暂未订购
Discrete element and finite element coupling simulation and experiment of hot granule medium pressure forming 被引量:3
12
作者 董国疆 赵长财 +1 位作者 押媛媛 赵建培 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第12期4089-4101,共13页
The granule medium of discreteness is supposed to be continuous(Drucker-Prager model) in the existing finite element simulation analysis on the hot granule medium pressure forming(HGMF) process, so the granule med... The granule medium of discreteness is supposed to be continuous(Drucker-Prager model) in the existing finite element simulation analysis on the hot granule medium pressure forming(HGMF) process, so the granule medium may produce tensile stress in the process of pressure-transferring and flowing, which does not coincide with the reality. The analysis method, discrete element and finite element(DE-FE) coupling simulation, is proposed to solve the problem. The material parameters of simulation model are obtained by the pressure-transfer performance test of granule medium and the hot uniaxial tensile test of sheet metal. The DE-FE coupling simulation platform is established by adopting Visual Basic language. The features in the process that AA7075-T6 conical parts are formed by the HGMF process are analyzed and verified by the process test. The studies show that the results of DE-FE coupling simulation coincide well with the test results, which provides a new analysis method to solve the mechanics problem in the coupling of discrete and continuum. 展开更多
关键词 granule medium aluminum alloy sheet hot forming finite element discrete element
在线阅读 下载PDF
Available Contents of Trace Nutrient Element and Factors Affecting Their Availability in Western Jilin 被引量:5
13
作者 施宪 王冬艳 +2 位作者 李月芬 靳克 郭珍 《Agricultural Science & Technology》 CAS 2010年第5期73-76,共4页
Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient ele... Based on the assay of the total content and available content of the trace nutrient elements and the soil pH and organic matter of the soil samples,the characteristic of the available content of the trace nutrient elements and their affecting factors are studied. The results show that the available B in western Jilin is in a middle level,the content in Nong'an is higher than that in the others; the available Mn is extremely abundant; the available Cu in Nong'an is obviously higher than other areas,and the content in Da'an differs greatly; the available Zn is in a middle level; the severe shortage of available Mo differs between different areas; and the available Fe is extremely abundant. The available Mn,Cu and Fe have significantly positive correlation with their total content; the available B has significantly positive correlation with pH,and Zn has obviously negative correlation with pH; the available Mn and Fe had significantly positive correlation with soil organic matter. 展开更多
关键词 trace nutrient element Available content The affecting factors Western Jilin
在线阅读 下载PDF
Determination of the Trace Element Contents in Plants Using Atomic Absorption Spectrophotometer 被引量:37
14
作者 高淑云 《Agricultural Science & Technology》 CAS 2008年第2期6-9,共4页
The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results sh... The aim of the study is to investigate the contents of trace element Se, Cd, Pb in three plants including burdock, ginkgol and garlic via graphite furnace atomic absorption and standard addition method. The results show that Se in burdock stem, skin and leaf are 32.40, 48.63, 38.10 μg/g, respectively; Cd in burdock stem, skin and leaf are 0. 160 0, 0. 300 0, 0. 140 0 μg/g, respectively; Cd in burdock stem, skin and leaf are 2. 020, 3. 960, 2. 410 μg/g, respectively. In the ginkgo and ginko leaf, Se contents are 17.63 and 16.91 μg/g, respectively ; for Cd are 0. 181 0 and 0.2020μg/g, respectively ; for Pb are 3. 572 and 4. 021 μg/g, respectively. In garlic, Se, Cd and Pb are 73. 900 0, 6. 900 0 and 0. 390 0, respectively. All the standard deviations of measured results are below 2.3%, recovery rate are from 99% to 101%. 展开更多
关键词 trace elements GFT AAS BURDOCK GINKGO GARLIC
在线阅读 下载PDF
Effects of Feed Fermentation on Chemical Fractionation of Trace Elements in Feed and Pig Manure and Skatole Content in Pig Manure 被引量:2
15
作者 盛清凯 战余铭 +3 位作者 孙延军 李祥明 孟宪利 赵红波 《Agricultural Science & Technology》 CAS 2016年第4期916-919,共4页
[Objective] This study aimed to promote the combination of cultivation and livestock farming, and to explore an environment-protecting farming style. [Method]The effects of anaerobically fermented complete compound so... [Objective] This study aimed to promote the combination of cultivation and livestock farming, and to explore an environment-protecting farming style. [Method]The effects of anaerobically fermented complete compound sow feed, added with Lactobacillus and Bacillus subtilis, on the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure and skatole content in pig manure were investigated. [Result] Compared with those in the non-fermented feed, in the fermented feed and pig manure, the acetic acid-extractable copper, iron, zinc and manganese contents increased significantly(P0.05), the reduced copper and iron contents increased significantly(P 0.05), the oxidized copper and iron contents reduced significantly(P0.05), and the residual copper contents remained unchangeable(P0.05). The pH value of fermented feed decreased significantly(P0.05), and that of pig manure increased significantly(P0.05). The skatole content in pig manure decreased significantly(P 0.01). The Lactobacillus abundance and amylase and cellulase activity increased significantly(P 0.05). [Conclusion] The fermentation of feed changed the chemical fractionation of copper, iron, zinc and manganese in feed and pig manure, and reduced the manure odor. 展开更多
关键词 FERMENTATION FEED MANURE trace element Chemical fractionation SKATOLE
在线阅读 下载PDF
Effect of trace elements on growth of Pinus tabulaeformis seedling 被引量:7
16
作者 刘晓东 《Journal of Forestry Research》 SCIE CAS CSCD 2002年第4期285-288,337,共4页
The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varie... The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrations at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and the treatment with low concentration was even better. The height or chlorophyll content of the seedlings with spray of low-concentration Mn and Mo element was much higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect on seedling growth. 展开更多
关键词 Pinus tabulaeformis trace element Seed soaking TOPDRESSING Seed germination Seedling growth
在线阅读 下载PDF
Inhibition Effects of Different Trace and Secondary Elements on Scab of Cucurbits(Cladosporium cucumerinum) and Their Effects on Enzyme Activities of Cucumber Plants
17
作者 娄春荣 邹晓锦 +3 位作者 何志刚 牛世伟 刘慧颖 董环 《Plant Diseases and Pests》 CAS 2011年第1期1-4,共4页
The paper was to explore the effect of trace and secondary elements on scab of cucurbits ( Cladosporium cucumerinum) and their effects on enzyme activities of cucumber plants. [ Method ] Indoor antifungd experiment ... The paper was to explore the effect of trace and secondary elements on scab of cucurbits ( Cladosporium cucumerinum) and their effects on enzyme activities of cucumber plants. [ Method ] Indoor antifungd experiment and pot test was carried out to study the control effect of different trace and secondary dements on scab of cucu.rbits; after trace and secondary element compounds were sprayed for 7 d, the content of soluble protein and malondialdehyde (MDA) and the activities of peroxidase (POD) and superoxide dismutase (SOD) of cucumber leaves during seedling stage were simultaneously detected. [ Result] The inhibi- tion effects on scab of cucurbits were found in the three trace and secondary dements, especially for the CaC12 (66.9%), and about 54.6% and 24.1% for ZnSO4 and H3 BO3 , respectively. When cucumber plants were infected by scab of cuea.rbits, the contents of MDA for all treatments were significantly decreased in cucum- ber leaves after spraying the three trace and secondary elements compared with control. The contents of soluble protein in cucumber seedling were increased by Zn- SO4 and H3 BO3 application, while the contents of POD and SOD were increased on ZnSO4 and CaCI2 treatments. The defense system of cucumber was induced and strengthened by application of the three trace and secondary elements. [ Conclusion ] The results provided the theoretical basis for practical application and research on resistance mechanism of using trace and secondary dements to control scab of eueurbits. 展开更多
关键词 trace and secondary element Antifungal experiment Scab of cucurbits Enzyme activity
在线阅读 下载PDF
Study on the Major and Trace Elements in Soil of Yunnan Farmland
18
作者 徐娟 刘刚 +3 位作者 赵兴祥 赵帅群 任静 胡建飞 《Agricultural Science & Technology》 CAS 2014年第12期2141-2144,共4页
In order to investigate the distribution of soil available micronutrients, and provide a theoretical basis for management of fertilizing reasonably on crops, the contents of major and trace elements (P, K, Ca, Mg, Cu... In order to investigate the distribution of soil available micronutrients, and provide a theoretical basis for management of fertilizing reasonably on crops, the contents of major and trace elements (P, K, Ca, Mg, Cu, Fe, Zn, and Mn) in farm- land soil collected from Yunnan Province were determined by inductively coupled plasma-mass spectrometry (ICP-MS), the contents and distribution of major and trace elements were also studied. The results showed that the contents of available P, K were balance, available Ca, Mg were deficient, and available Cu, Fe, Zn, Mn were very plentiful. Major and trace elements distribution of different landform areas were obviously different. The contents of trace elements (Fe, Zn and Mn) of central Yunnan Red Plateau were significantly higher than those of Hengduan Mountains in western Yunnan and those of karst plateau in eastern Yunnan. The contents of available P, K, and Ca gradually declined from west to east, while the content of available Cu rose gradually from west to east. The results are reference value to elements determination and agricultural production in farmland soils. 展开更多
关键词 ICP-MS Soil of Yunnan farmland Major elements trace elements CONTENT
在线阅读 下载PDF
Clinical and experimental study on gastric mucosal Pathology DNA cAMP and trace elements of pixu patients
19
作者 尹光耀 何雪芬 尹玉芬 《World Journal of Gastroenterology》 SCIE CAS CSCD 1996年第1期44-50,共7页
AIMS The paper studies the relationship between spleen deficiency substance,spleen deficiency and gastric cancer. METHODS We adopted the IBAS 2000 image analysis system,501B SEM with 9100/60 energy chromatic dispersin... AIMS The paper studies the relationship between spleen deficiency substance,spleen deficiency and gastric cancer. METHODS We adopted the IBAS 2000 image analysis system,501B SEM with 9100/60 energy chromatic dispersing X-ray analysis instrument technique,histologic chemistry and radio-immunity means to assay the ultramicro structure,in- testinal rnetaplasia subtypes,cAMP,DNA,trace element series and their oxides of the patients' gastric mucosa. RESULTS The incidence rates of gastric cancer,incom- plete colonic intestinal metaplasia and“background lesion”of spleen deficiency with Qi stagnation patients are remarkably higher than those of spleen Qi deficiency patients(P<0.05- 0.001 ).The levels of gastric mucosa cAMP,Zn,Cu,ZnO and CuO decreased from complete to incomplete intestinal meta- plasia and from small to colonic intestinal metaplasia,while DNA increased in the above sequence(P<0.05-0.001 ).The lev- els of DNA,cAMP,Zn,Cu,ZnO and CuO in gastric mucosa of incomplete colonic intestinal metaplasia tissue are not remark- ably different from those in gastric cancer tissue. CONCLUSION Gastric diseases of spleen dificiency with Qi stagnation has the tendency of cancerization; There is a close relationship between the incidence of incomplete colonic intestinal metaplasia and gastric cancer. 展开更多
关键词 Spleen asthenia gastric macosa DNA Cyclic AMP trace elements
暂未订购
Study on Trace Elements in Rehmannia glutinosa Libosch. by Principal Component Analysis and Clustering Analysis
20
作者 申明金 陈丽 曹洪斌 《Agricultural Science & Technology》 CAS 2013年第12期1764-1768,共5页
[Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering anal... [Objective] This study aimed to investigate the trace elements in Rehman- nia glutinosa Libosch. by using principal component analysis and clustering analysis. [Method] Principal component analysis and clustering analysis of R. glutinosa medicinal materials from different sources were conducted with contents of six trace elements as indices. [Result] The principal component analysis could comprehen- sively evaluate the quality of R. glutinosa samples with objective results which was consistent with the results of clustering analysis. [Conclusion] Principal component analysis and clustering analysis methods can be used for the quality evaluation of Chinese medicinal materials with multiple indices. 展开更多
关键词 Rehmannia glutinosa Libosch. (Radix Rehmanniae) trace elements Principal component analysis Clustering analysis
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