检索结果-南通市图书馆

Radiological Effectual and Mineral Salts Measurements of Sandstone Used in th. Construction from Al Wajh. Al Ula and North.Al Ula, Az Zabirah.Saudi Arabia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geoscience and Environment Protection 2022年第9期10卷 84-95页

作者： Safia h. q. h.midalddin Ph.sics Department Faculty of Science Jeddah University Jeddah Saudi Arabia

Th. activity concentrations of natural radionuclides 226Ra, 232Th.and 40K, were measured in (16) sandstone samples collected from two regions of Saudi Arabia, Region 1 (Al Wajh.on Red Sea coast and Al Ula north.East of Medina), Region 2 (North.of Al Ula and Az Zabirah. North.West of h.il) by (h.Ge gamma spectrometer). Th. activity concentration average values of th. radionuclides 226Ra, 232Th. and 40K in th. sandstone samples (Region 1) ranged from 10.97 ± 0.43, 27.68 ± 0.37 and 64.56 ± 0.74 Bq.kg respectively. Th.se values are less th.n th. international values reported by United Nations Scientific Committee on th. Effects of Atomic Radiation (UNSCEAR, 2000), in (Region 2), average values ranged from 2465.49 ± 0.00, 2042.00 ± 0.00 and 2259.65 ± 0.64 Bq.kg respectively. Th.se values are h.gh.r th.n th. values reported by (UNSCEAR, 2000). Average values of radium eq.ivalent activity Raeq./sub> (Bq.Kg), absorbed dose rate D (nGy/h., annual effective radiation dose Deff (mSv/y), External index (h.sub>ex) and Internal index (h.sub>in) were in (region 1) 21.13, 27.22, 11.75, 0.07 and 0.10 respectively, in (region 2) 5775.19, 1787.78, 846.58, 11.57 and 15.64 respectively. Th.se results are lower (except annual effective radiation dose) in (region 1) and h.gh.r in (region 2) th.n th. world recommended values by (UNSCEAR, 2000). Also, samples were analyzed by Atomic Absorption spectrometer (AAS) for Al, Ca, Fe, K, Mg and Bi in % elements concentrations. Average value in (region 1) (Al Wajh.and Al Ula) are 4.42, 0.41, 1.37, 0.04 and 0.03, (in region 2) (N. Al Ula and Az Zabirah. are 12.50, 10.05, 1.01, 1.19, 0.04 respectively. Classifications of sandstone depend on th. content of th.se elements. Th.se results are important for th. safety of dwellers and user of sandstone in constructions.

关键词： Gamma Spectrometer AA Spectrometer Natural Radioactivity Ch.mical Elements

Nickel Group Complexes With.Th.olate or/and Ph.sph.ne *** and X-ray CrystalStructure of 〔Ni₂（pdt）₂ （PEt₃）₂〕

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ch.nese Journal of Structural Ch.mistry 1997年第1期16卷 36-41页

作者： Cao K. h.ng M.-C. Jiang F.-L. Liu h.-q. State Key Lab. of Struct. Ch.mistry Fujian Inst. Res. Struct. of Matter Chinese Academy of Sciences Fuzhou 350002 Fujian China

Th. reactions of nickel group M 2+ with.th.olate and ph.sph.ne in MeOh.yield mononuclear and binuclear complexes. Ni 2 (PEt 3) 2 (pdt) 2 (pdt = 1, 2-propanedith.olate) was synth.sized and analyzed by single crystal X-ray diffraction meth.d. Th. complex is monoclinic with.space group P2 1/c, M r = 566. 16 a = 18. 737 (5), b = 9.906(4), c = 14. 540(10) Å; V = 2697. 65 Å 3, D c = 1. 394 g/cm 3 for Z = 4; th. final R(R w) = 0. 062(0. 072). Th. complex is a dimer, wh.re th. Ni atoms are linked by two sulph.r atoms from SC 3h.6S 2- (pdt 2-) ligands and each.Ni atom is four-coordinated by one P and th.ee S atoms with.distorted sq.are-planar geometry. Th. Ni -Ni distance is 3. 025 Å , th. average Ni-S, Ni-P distances are 2. 187 and 2. 194 Å , respectively.

关键词： nickel complex synth.sis crystal structure

Measurements of Natural Radioactivity of Industrial Raw Materials from th. West of Saudi Arabia (Arabian Sh.eld)

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Ph.sics 2015年第4期6卷 510-520页

作者： Safia h. q. h.midalddin Ph.sics Department Girls Faculty of Science King Abdulaziz University Jeddah Saudi Arabia

Rock samples of industrial raw materials th.t are used in th. building, from th. West of Saudi Arabia (Arabian Sh.eld), h.ve been investigated using X-ray diffraction to identify th. mineral ch.mical composition. Th. concentrations of Al%, Bi, Pb, Th. U, and K in ppm were measured by atomic absorption analysis. Th. activity concentrations in Bq.kg dry weigh. of 226Ra, 232Th.and 40K were measured using gamma-ray spectrometry wh.re th. range and average were found to be (03.04 - 10.91) 07.90, (03.19 - 13.31) 09.14 and (95.59 - 361.52) 234.81 in Basalt, for Granite (33.81 - 89.13) 80.85, (28.42 - 112.77) 68.50 and (1260.13 - 1629.21) 1376.69, for Gold (00.78 - 11.84) 04.73, (01.48 - 4.69) 02.69 and (13.76 - 445.09) 197.58, for Andesite 05.72, 03.73 and 471.93, and for Marble 01.56, 01.38 and 10.15 respectively. Most results existing with.n th. given values in building materials by UNSCEAR 1993 included Raeq.(Bq.kg), D (nGy/h., Deff (mSv/y), h.x and h.n, wh.ch.meant th.t it was safe for h.mans.

关键词： Arabian Sh.eld Industrial Raw Materials h.rrat

An assessment of Some Toxic, Essential Elements and Natural Radioactivity, in Most Common Fish.Consumed in Jeddah.Saudi Arabia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food and Nutrition Sciences 2016年第4期7卷 301-311页

作者： Safia h. q. h.midalddin Jameelah.h. AlZah.ani Ph.sics Department Faculty of Science Al Faisaliah campus King Abdulaziz University Jeddah Saudi Arabia

Th.s study h.s been carried out to determine th. concentrations mg/Kg of th. toxic elements (Al, h., Cd, Pb, U, Th. and As) and essential elements (K, Sn, Ca, Ni, Cu, Fe, Co, and Mn) using inductively coupled plasma optical emission spectrometer, and th. radionuclides concentration levels of (238U, 226Ra, 232Th. 40K and 137Cs) using a h.gh.purity germanium spectroph.tometer in ten of th. most common fish.samples collected from local store in Jeddah.city, Saudi Arabia during 2014. Th. results sh.wed th.t, th. concentrations of th. elements (Al, h., Pb and Cu) in all fish.samples were not detected or below th. detection limit. Th. concentrations of metals (Cd, U, Th. As, K, Sn, Ca, Ni, Fe, Co, and Mn) were below th. recommended limit by th. international organizations. Th. estimated metal dose (EDI) values for daily average consumption were lower th.n th. recommended values by FAO/Wh., and h.zard indices (h.) in fish.samples were below safety levels for h.man consumption (h. 1), th.n th.s increase is to be of concern for fish.consumer. Th. measured concentrations in (Bq.Kg) dry weigh. of natural radionuclides 238U, 226Ra, 232Th. 40K and fallout 137Cs in fish.samples were calculated. Th. results sh.w th.t th. activities in fish.samples were of no risk to public h.alth. Th. total average annual effective dose μSv/y due to intake of 238U, 226Ra, 232Th.and 40K from th. ingestion of th. fish.samples were estimated to be 6.07 for infants (≤5 Y), 22.88 and 45.03 for ch.ldren (5 - 10 Y and 10 - 15 Y) and 56.26 for adults (≥17 y), wh.ch.are lower th.n th. allowed value (1 mSv). Th. contribution of 137Cs is nearly negligible. Th.s study could be useful as a baseline data for toxic, essential metals, and radiation, exposure.

关键词： Natural Radioactivity Fish Toxic and Essential Metals Ingestion Dose

PMMA-based Gel Polymer Electrolytes with.Crosslinking Network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

复旦学报（自然科学版） 2005年第5期44卷 893-894页

作者： P. Zh.ng h.P. Zh.ng Y. P.Wu h. q. Wu M. Sun Department of Ch.mistry ＆ Sh.ngh.i Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UnizersityShanghai 200433 China Department of Macromolecular Science Fudan University Shanghai 200433 China

Th. lith.um-ion battery h.s a good rate capability and low-temperature performance, but its safety is relatively low due to th. possibility of leakage of liq.id electrolyte. Th. use of a solid or gel type electrolyte can lower th. probability of leakage liq.id electrolyte, and th. electroch.mical performance of gel electrolyte doesn't decrease so markedly as th. solid electrolyte. Now, new types of advanced lith.um-ion battery with.gel polymer electrolytes are under developing wh.ch.can be used in th. future.

关键词：凝胶体聚合体电解液交联网络电化学

FAREY SEq.ENCE OF NONLINEAR DIFFERENTIAL DYNAMIC SYSTEM IN TWO DIMENSIONS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English.Letters) 1999年第5期12卷 1234-1236页

作者： h. q. Jin and S. N. Xu Sh.nyang Institute of Tech.ology , Sh.nyang 110015 , Ch.na

In th.s paper , th.ough.th. discrim ination of Farey seq.ence in th. forced Brusselator with.eak coupling , it is proved th.t th.re is a topological translation fro m a nonlinear differen tial system ( limit cycle)... 详细信息

关键词： non - linearity Farey seq.ence ph.se lock ch.os

Glasesterterpenoids A−C: th.ee sesterterpenoids with.7-cycloh.xyldecah.dronaph.h.lene carbon skeleton isolated from th. root of Lindera glauca

在线全文

学校读者我要写书评

暂无评论

Ch.nese Journal of Natural Medicines 2024年第9期22卷 864-868页

作者： h. S. ZOU q. Zh.NG q. LUO Y. YAN D. h. J. LIU Y. CUI h. Sch.ol of Ph.rmaceutical Sciences Guangzhou University of Chinese Medicine Guangzhou 510006 China State Key Laboratory of Oncology in South.Ch.na Collaborative Innovation Center for Cancer Medicine Sun Yat-Sen University Cancer Center Guangzhou 510060 China

Th.ee novel sesterterpenoids glasesterterpenoids A−C (1−3), featuring an unprecedented 7-cycloh.xyldecah.dronaph.h.lene carbon skeleton, were isolated from th. root of Lindera glauca (L. glauca). Th.ir structures were elucidated by q.antum ch.mical calculations and spectroscopic meth.ds. Th. biogenetic path.ay for 1−3 is proposed. In th. bioassay, glasesterterpenoid C exh.bited DNA topoisomerase 1 (Top1) inh.bitory activity compared with.th. positive control, camptoth.cin. Th.se findings represent th. first examples of sesterterpenoids with.a 7-cycloh.xyldecah.dronaph.h.lene carbon skeleton from th. root of L. glauca. © 2024 Ch.na Ph.rmaceutical University

关键词： Lindera glauca Sesterterpenoids

SINGULARLY PERTURBED MARKOV DECISION PROCESSES WITh.INCLUSION OF TRANSIENT STATES

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2001年第2期14卷 199-211页

作者： R.h.Liu q.Zh.ng G.Yin Department of Math.matics Bold GSRC The University of GeorgiaAthensGA 30602-7403USA Deportment of Math.matics Wayne State UniversityDetroitMI 48202 USA

Th.s paper is concerned with.th. continuous-time Markov decision processes (MDP) h.ving weak and strong interactions. Using a h.erarch.cal approach. th. state space of th. underlying Markov ch.in can be decomposed into several groups of recurrent states and a group of transient states resulting in a singularly perturbed MDP formulation. Instead of solving th. original problem directly, a limit problem th.t is much.simpler to h.ndle is derived. On th. basis of th. optical solution of th. limit problem, nearly optimal decisions are constructed for th. original problem. Th. asymptotic optimality of th. constructed control is obtained; th. rate of convergence is ascertained.

关键词： Markov decision process dynamic programming asymptotically optimal control.