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THE FEED BACK INHIBITION EFFECT ON THEINFECTIOUS DEVELOPMENT CAUSED BY N'-ACYL-N-PHENYLHYDRAZINE
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作者 Ping CHEN Ren De SUN De Shui ZHENG Institute of Photographic Chemistry,Academia Sinica,Beijing 100101 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第1期5-8,共4页
The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which pr... The phenyl and methyl phenyl free radicals,formed in the oxidation-hydrolysis process of N’-acyl-N-phenylhydrazine, have been studied by ESR spectrometry.It was found that the free radical is the chief cause which produces the feed-back inhibition effect in the hydrazine-promoted infectious development of silver halide. 展开更多
关键词 ESR ACYL-n-PHEnYLHYDRAZInE THE FEED BACK InHIBITIOn effect On THEInFECTIOUS DEVELOPMEnT CAUSED BY n
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Establishment of ANEDr model for evaluating absorbed-nitrogen effects on wheat dry matter production
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作者 ZHAO Jiao TAO Hong-bin +1 位作者 LIAO Shu-hua WANG Pu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第10期2257-2265,共9页
Applying mathematic models to evaluate absorbed-N effects on dry matter production at different developmental stages would help determine proper nitrogen management according to crop demands and yield target. Two fiel... Applying mathematic models to evaluate absorbed-N effects on dry matter production at different developmental stages would help determine proper nitrogen management according to crop demands and yield target. Two field trials were carried out for establishing absorbed-N effects on dry matter production(ANEDr) model, using uniform design in 2010–2011and 2012–2013 winter wheat growing seasons in Hebei Province, China. Another field trial was carried out in 2010–2011for model validation. Dry matter and N concentration in leaf and non-leaf organs were measured at setting, jointing, anthesis, and maturity. Theory of best linear unbiased prediction(BLUP) was applied to analyse the N effects of leaf and non-leaf organs on dry matter production. Within ANEDr model, four N-affected phases at each stage were concerned,leaf absorbed-N effect before this stage, non-leaf organ absorbed-N effect before this stage,leaf absorbed-N effect at this stage, and non-leaf organ absorbed-N effect at this stage. In addition, developmental processes, genotype characters and temperature were three factors that determine each N effect. It was demonstrated that ANEDr model can precisely quantify absorbed-N effects on dry matter production with high correlation coefficient(r=0.95). Comparing with other models, ANEDr model considered both leaf and non-leaf organs according to developmental processes of winter wheat, showed higher flexibility and simplicity, thus could be applied to different environments, cultivars and crops after parameter adjustment. 展开更多
关键词 winter wheat BLUP effects of absorbed-n dry matter production
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培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对患者血浆N末端B型利钠肽原水平的影响
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作者 张金春 王朝霞 李志华 《陕西医学杂志》 CAS 2025年第1期109-113,共5页
目的:探究培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对血浆N末端B型利钠肽原(NT-ProBNP)水平的影响。方法:选择原发性高血压伴左心室肥厚患者138例为研究对象,按随机数表法分为三组,均46例。对照组1予以氨氯地平治疗... 目的:探究培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对血浆N末端B型利钠肽原(NT-ProBNP)水平的影响。方法:选择原发性高血压伴左心室肥厚患者138例为研究对象,按随机数表法分为三组,均46例。对照组1予以氨氯地平治疗,对照组2予以培哚普利治疗,观察组采用培哚普利联合氨氯地平治疗。比较临床疗效、治疗前后血压情况、舒张末期左室内径(LVDd)、室间隔厚度(I与T)、左室后壁厚度(PWT)、左室重量指数(LVMI)及NT-ProBNP、同型半胱氨酸(Hcy)心钠肽(ANP)水平。结果:观察组总有效率为95.65%(44/46)高于对照组1[80.43%(37/46)]和对照组2[76.09%(35/46)](均P<0.05),对照组1和对照组2比较无统计学差异(P>0.05)。治疗前,三组收缩压、舒张压、I与T、PWT、LVMI及血清NT-ProBNP、Hcy、ANP水平比较,差异无统计学意义(均P>0.05),治疗后,观察组收缩压(127.87±13.66与136.46±15.73与135.00±15.98)、舒张压(81.07±5.58与83.98±7.16与85.57±7.22)、LVDd(46.48±2.24与48.37±3.62与48.30±3.57)、I与T(10.00±1.38与11.20±1.50与11.24±1.55)、PWT(10.52±1.35与12.24±1.40与12.37±1.39)、LVMI(124.57±10.80与145.13±10.27与144.93±10.34)、NT-ProBNP(64.53±15.63与75.23±18.46与78.15±18.54)、Hcy(8.93±2.68与15.48±4.66与14.88±4.62)、ANP(139.95±38.64与216.84±59.15与213.87±59.23)水平均较对照组1和对照组2下降(均P<0.05),对照组1和对照组2比较无统计学差异(P>0.05)。结论:培哚普利联合氨氯地平对原发性高血压伴左心室肥厚治疗效果较好,可有效降低血压、改善左室相关指标,并降低NT-Pro BNP水平。 展开更多
关键词 培哚普利 氨氯地平 原发性高血压伴左心室肥厚 血浆n末端B型利钠肽原水平 逆转作用
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High-performance n-channel organic thin-film transistors based on the dual effects of heterojunction and surface modification
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作者 曹进 洪飞 +6 位作者 邢菲菲 顾文 郭新安 张浩 魏斌 张建华 王军 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第3期456-461,共6页
This paper presents two n-channel organic heterojunction transistors with modified insulator by using hexadecafiuorophthalocyaninatocopper (F16CuPc)/copper phthalocyanine (CuPc) and F16CuPc/pentacene as the active... This paper presents two n-channel organic heterojunction transistors with modified insulator by using hexadecafiuorophthalocyaninatocopper (F16CuPc)/copper phthalocyanine (CuPc) and F16CuPc/pentacene as the active layers. Compared with a single-layer device, it reports that an improved field-effect mobility and a 6-fold higher drain current are observed. The highest mobility of 0.081 cm^2/(V. s) was obtained from F16CuPc/CuPc heterojunction devices. This result is attributed to the dual effects of the organic heterojunction and interface modification. Furthermore, for two heterojunction devices, the performance of the F16CuPc/CuPc-based transistor is better than that of F16CuPc/pentacene. This is attributed to the morphologic match of two organic components. 展开更多
关键词 n-CHAnnEL heterojunction effect surface modification
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两种咔唑基-吡啶-N-氧化物内盐荧光极性探针研究
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作者 梁文娟 王慧敏 +1 位作者 白云峰 冯锋 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第6期1600-1606,共7页
合成了4-(9H-咔唑-9-基)吡啶1-氧化物(CPNO)和4-(4-(9H-咔唑-9-基)苯基)吡啶1-氧化物(CPPNO)两种咔唑基-吡啶-N-氧化物内盐,测定了它们在不同溶剂中的紫外-可见吸收和荧光光谱,均表现出对溶剂极性较好的敏感性。计算表明,两个化合物都... 合成了4-(9H-咔唑-9-基)吡啶1-氧化物(CPNO)和4-(4-(9H-咔唑-9-基)苯基)吡啶1-氧化物(CPPNO)两种咔唑基-吡啶-N-氧化物内盐,测定了它们在不同溶剂中的紫外-可见吸收和荧光光谱,均表现出对溶剂极性较好的敏感性。计算表明,两个化合物都具有较大的激发态偶极矩,是化合物溶剂极性敏感性的原因。研究为开发新型的荧光极性探针提供了一种新思路。 展开更多
关键词 咔唑基 吡啶 n氧化物内盐 溶剂效应 荧光极性探针
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基于N-P关联式计算溶剂化吉布斯自由能
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作者 黄赛金 禹新良 《湖南工程学院学报(自然科学版)》 2024年第2期53-57,共5页
溶剂化吉布斯自由能(ΔG_(solv))是一个重要的热力学参数,广泛用于化学、生物、药理等领域.尽管计算溶剂化吉布斯能的模型众多,但仍缺乏简易高效的预测模型.本文提出一种基于Arrhenius方程的N-P关联式计算方法,其中参数N、P分别描述溶剂... 溶剂化吉布斯自由能(ΔG_(solv))是一个重要的热力学参数,广泛用于化学、生物、药理等领域.尽管计算溶剂化吉布斯能的模型众多,但仍缺乏简易高效的预测模型.本文提出一种基于Arrhenius方程的N-P关联式计算方法,其中参数N、P分别描述溶剂-溶质体系的非极性效应及极性效应对溶剂化吉布斯能的贡献.当溶剂及溶质分子被赋予经验参数N、P值时,基于N-P关联式能对任何溶剂-溶质对的溶剂化吉布斯能进行计算.将6 238个溶剂化吉布斯能数据对N-P关联式进行了测试,均方根误差仅为0.698 kcal/mol,低于测试精度1 kcal/mol,证实了本文提出的N-P关联式能快速计算溶剂化吉布斯自由能. 展开更多
关键词 n-P关联式 非极性效应 极性效应 溶剂化吉布斯能
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Computer modelling and analysis of the photodegradation effect in a-Si:H p–i–n solar cell 被引量:1
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作者 A.F Bouhdjar L.Ayat +2 位作者 AM.Meftah N.Sengouga AF.Meftah 《Journal of Semiconductors》 EI CAS CSCD 2015年第1期52-59,共8页
Using a previous model, which was developed to describe the light-induced creation of the defect density in the a-Si:H gap states, we present in this work a numerical modelling of the photodegradation effect in the a... Using a previous model, which was developed to describe the light-induced creation of the defect density in the a-Si:H gap states, we present in this work a numerical modelling of the photodegradation effect in the a-Si:H p–i–n solar cell under continuous illumination. We first considered the simple case of a monochromatic light beam with a wavelength λ between 530–540 nm non uniformly absorbed, then the global standard solar spectrum(AM1.5) illumination is taken into account. The photodegradation is analysed on the basis of the resulting changes in the free carrier's densities, recombination rate, band structure, electrical potential and field, space charge, and current densities. Changes in the cell's external parameters: the open circuit voltage Voc, the short circuit current density Jsc, the fill factor FF and the maximum power density Pmaxare also presented. 展开更多
关键词 a-Si:H Staebler–Wronski effect p–i–n
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Tribological study of N-containing borate derivatives and their synergistic antioxidation effects with T531 被引量:3
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作者 Liping XIONG Zhongyi HE +5 位作者 Jian LIU Jianqiang HU Xu XIN Sheng HAN Yinglei WU Shaoming YANG 《Friction》 SCIE CSCD 2019年第5期417-431,共15页
Two N-containing borates, BTES and BMES, were synthesized with dodecyl phenol, 2-(N-containing heterocyclic) ethan-1-ol, boric acid, and dibutylamine, and their tribological properties in rapeseed oil(RSO) were invest... Two N-containing borates, BTES and BMES, were synthesized with dodecyl phenol, 2-(N-containing heterocyclic) ethan-1-ol, boric acid, and dibutylamine, and their tribological properties in rapeseed oil(RSO) were investigated using a four-ball tester. The results showed that the load-carrying ability(P_B value) of RSO can be improved by 40.9% and 67.9%, respectively, when using 0.5 wt% BTES and BMES. Moreover, the antiwear and friction-reducing performances of the additive-containing oils increased with the additive concentration. The X-ray photoelectron spectroscopy results of the worn steel ball surfaces showed that BTES and BMES formed protective films, which contained boron oxide, iron oxide, ferrous sulfate, ferrous sulfide(for BMES), and other organic nitrogen compounds, on the metal surfaces. The better load-carrying and antiwear performances of BMES than those of BTES might be due to their different sulfur contents, which result in different tribochemical reaction films on the contact surfaces. The oxidation stability tests showed that BTES and BMES possessed synergistic antioxidation activity with N-phenyl-α-naphthylamine(T531), and consequently, the oxidation activation energy of the oil sample increased by 77.85% and 82.19%, respectively, compared with that of RSO when the oil sample contained 0.05 wt% BTES/BMES and 0.25% T531. 展开更多
关键词 n-containing BORATE SYnERGISTIC AnTIOXIDATIOn effect T531 TRIBOLOGICAL property
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Effects of Nitrogen Addition on the Mixed Litter Decomposition in Stipa baicalensis Steppe in Inner Mongolia 被引量:1
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作者 Wenya Li Wenchao Yu +2 位作者 Long Bai Hongmei Liu Dianlin Yang 《American Journal of Plant Sciences》 2016年第3期547-561,共15页
During the past two centuries, global changes (i.e., enhanced nitrogen deposition) have exerted profound effects on ecological processes of steppe ecosystems. We used litterbag method and mixed litters of three differ... During the past two centuries, global changes (i.e., enhanced nitrogen deposition) have exerted profound effects on ecological processes of steppe ecosystems. We used litterbag method and mixed litters of three different plant species tissues (Stipa baicalensis: Sb, Leymus chinensis: Lc and Artemisia frigid: Af), endemic to Stipa baicalensis Steppe, and measured the mass loss of mixtures over 417 days under the N addition treatment. We studied the effect of N addition (N0: no N addition;N15: 1.5 g N/m<sup>2</sup>·a;N30: 3.0 g N/m<sup>2</sup>·a;N50: 5.0 g N/m<sup>2</sup>·a;N100: 10.0 g N/m<sup>2</sup>·a;N150: 15.0 g N/m<sup>2</sup>·a) on the rate of mixed litter decomposition and nutrient dynamics change. The decomposition constant (k) of leaf mixtures was higher than that of root mixtures. The k values of leaf mixed combinations were 0.880 (Sb + Lc), 1.231 (Lc + Af), 1.027 (Sb + Lc + Af), respectively. The k value of stem was 0.806 (Lc + Af) and the root mixed combinations were 0.665 (Sb + Lc), 0.979 (Lc + Af) and 1.164 (Sb + Lc + Af), respectively. The results indicated that N addition had significantly effect on the mixed litter decomposition and nutrient releasing. The rate of plant tissues litter decomposition had different response to N addition. In the context of N addition, litter decomposition rate and nutrient dynamics were changed by synthetic effect of decaying time, specie types and N addition dose. Our findings suggested that prairie plants may adapt to environmental change by adjusting litter quality, thus retaining the stability of the steppe ecosystem. 展开更多
关键词 GRASSLAnD Litter Decomposition Mixed effect n Addition Mass Loss nutrient Dynamics
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Effects of N/Z on Post-Saddle γ Emission as an Observable of Post-Saddle Nuclear Friction
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作者 陈娜 叶巍 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第4期731-734,共4页
Based on a dynamical Langevin equation coupled with a statistical decay model, we calculate the variation of the post-saddle giant dipole resonance (GDR) q-ray multiplicity of the heavy nuclei 24^240Cf, ^246Cf, ^252... Based on a dynamical Langevin equation coupled with a statistical decay model, we calculate the variation of the post-saddle giant dipole resonance (GDR) q-ray multiplicity of the heavy nuclei 24^240Cf, ^246Cf, ^252Cf and ^240U with the post-saddle friction strength (13). We find that the sensitivity of the post-saddle γ emission to β decreases considerably with increasing the neutron-to-proton ratio (N/Z) of the system. Moreover, for 240 U, the γ emission is no longer sensitive to 13. We suggest that to accurately obtain information of the post-saddle friction strength by measuring pre-scission GDR γ-ray multiplicities, it is optimal to choose among the various compound systems those with low N/Z. 展开更多
关键词 nuclear dissipation pre-scission 7-ray multiplicity n/Z effect Langevin model
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Effects of N/Z on Spin Distribution of Evaporation Residue Cross Section as a Probe of Nuclear Dissipation
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作者 YE Wei YANG Hong-Wei CHEN Na 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第9期729-732,共4页
The spin distribution of the evaporation residue cross section of nuclei ^194pb, ^200Pb, ^206Pb, and ^200 Os are calculated via a Langevin equation coupled with a statistical decay model. It is shown that with increas... The spin distribution of the evaporation residue cross section of nuclei ^194pb, ^200Pb, ^206Pb, and ^200 Os are calculated via a Langevin equation coupled with a statistical decay model. It is shown that with increasing the neutronto-proton ratio (N/Z) of the system, the sensitivity of the significantly. Moreover, for ^200Os this spin distribution is no spin distribution to the nuclear dissipation is decreased longer sensitive to the nuclear dissipation. These results suggest that to obtain a more accurate pre-saddle viscosity coefficient through the measurement of the evaporation residue spin distribution, it is best to yield those compound systems with low N/Z. 展开更多
关键词 evaporation residue spin distribution n/Z effect nuclear dissipation Langevin equation
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Damaging Effect of Low Energy N^+ Implantation on Aspergillus niger Spores
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作者 王力生 蔡克周 +4 位作者 程茂基 陈丽娟 刘雪兰 张束清 余增亮 《Plasma Science and Technology》 SCIE EI CAS CSCD 2007年第3期307-311,共5页
The mutant effects of a keV range nitrogen ion (N+) beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance (ESR) results showed that... The mutant effects of a keV range nitrogen ion (N+) beam on enzyme-producing probiotics were studied, particularly with regard to the induction in the genome. The electron spin resonance (ESR) results showed that the signal of ESR spectrum existed in both implanted and non-implanted spores, and the yields of free radicals increased in a dose-dependent manner. The ionic etching and dilapidation of cell wall could be observed distinctly through the scanning electron microscope (SEM). The mutagenic effect on genome indicated that N+ implantation could make base mutation. This study provided an insight into the roles low-energy ions might play in inducing mutagenesis of micro-organisms. 展开更多
关键词 low energy n damage effect aspergillus niger spores
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Effect of Different Amendments on Nitrogen Conservation During Simulated Composting
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作者 Li Danyang Qi Chuanren +2 位作者 Wei Yanan Li Guoxue Yuan Jing 《Journal of Environmental Science and Engineering(B)》 2019年第6期215-222,共8页
The objectives of this study were to evaluate the effects of different dosages of three amendments—peat,superphosphate,mixture of Mg(OH)2+H3PO4(Magnesium Hydroxide and Phosphorus Acid)on N(Nitrogen)conservation.The s... The objectives of this study were to evaluate the effects of different dosages of three amendments—peat,superphosphate,mixture of Mg(OH)2+H3PO4(Magnesium Hydroxide and Phosphorus Acid)on N(Nitrogen)conservation.The simulated composting experiment was carried out in a constant temperature water bath with pig manure and corn straw.The results showed that the ammonia volatilization could be inhibited to some extent under the treatments with fixing agents.Under the same simulated composting conditions,the nitrogen fixation effect of the three kinds of fixatives with the same proportion was as follows:Mg(OH)2+H3PO4>superphosphate>peat.The fixation effect of N increased with the increase of the additives.The N fixation rate of Mg(OH)2+H3PO4 treatment was up to 66%.Compared with the CK(Control Group),the amount of cumulative ammonia emission decreased by 90.3% and the TN(Total Nitrogen)content increased by 39.31% in this treatment.Compared with other two kinds of fixing agents,Mg(OH)2+H3PO4 treatment could not only control N loss in composting process,improve the N nutrient content of compost products,but also could increase P(Phosphorus)and Mg(Magnesium)nutrients.Therefore,it had more popularization value and application prospect. 展开更多
关键词 Simulated composting AMEnDMEnT effect of n conservation
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Noticeable positive Doppler effect on optical bistability in an N-type active Raman gain atomic system 被引量:2
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作者 常增光 钮月萍 +1 位作者 张敬涛 龚尚庆 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第11期280-284,共5页
We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion... We theoretically investigate the Doppler effect on optical bistability in an N-type active Raman gain atomic system inside an optical ring cavity. It is shown that the Doppler effect can greatly enhance the dispersion and thus create the bistable behaviour or greatly increase the bistable region, which has been known as the positive Doppler effect on optical bistability. In addition, we find that a positive Doppler effect can change optical bistability from the hybrid dispersion-gain type to a dispersive type. 展开更多
关键词 positive Doppler effect optical bistability n-type atomic system active Raman gain
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Radiation effect on the optical and electrical properties of CdSe(In)/p-Si heteroj unction photovoltaic solar cells
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作者 M.Ashry S.Fares 《Journal of Semiconductors》 EI CAS CSCD 2012年第10期1-4,共4页
The efficiency and radiation resistance of solar cells are graded.They are then fabricated in the form of n-CdeSe(In)/p-Si heterojunction cells by electron beam evaporation of a stoichiomteric mixture of CdSe and In... The efficiency and radiation resistance of solar cells are graded.They are then fabricated in the form of n-CdeSe(In)/p-Si heterojunction cells by electron beam evaporation of a stoichiomteric mixture of CdSe and In to make a thin film on a p-Si single crystal wafer with a thickness of 100μm and a resistivity of~1.5Ω·cm at a temperature of 473 K.The short-circuit current density(jsc),open-circuit voltage(Voc),fill factor(ff) and conversion efficiency(η) under 100 mW/cm^2(AMI) intensity,are 20 mA/cm^2,0.49 V,0.71 and 6%respectively. The cells were exposed to different electron doses(electron beam accelerator of energy 1.5 MeV,and beam intensity 25 mA).The cell performance parameters are measured and discussed before and after gamma and electron beam irradiation. 展开更多
关键词 n-CdSe(In)/p-Si solar cells performance electron beam radiation effects
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Synthesis of two derivatives of tigogenyl disaccharides containing N-acetylglucosamine and the long range shielding effect of benzoyl groups
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作者 Shu Jie Hou Liang Zhou Ping Sheng Lei De Quan Yu 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第4期373-376,共4页
Two tigogenyl glycosides containing N-acetylglucosamine were synthesized. Their structures were confirmed by ^1H and ^13C NMR spectra. The shielding effect caused by benzoyl groups was elucidated by ^1H NMR, COSY, HSQ... Two tigogenyl glycosides containing N-acetylglucosamine were synthesized. Their structures were confirmed by ^1H and ^13C NMR spectra. The shielding effect caused by benzoyl groups was elucidated by ^1H NMR, COSY, HSQC, HMBC spectroscopy. 展开更多
关键词 n-ACETYLGLUCOSAMInE GLYCOSYLATIOn Shielding effect
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Effects of N on Electronic and Mechanical Properties of H-Type SiC
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作者 刘运芳 成来飞 +1 位作者 曾庆丰 张立同 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第8期135-138,共4页
Structural, electronic and mechanical properties of the nH-SiC (n = 2, 4, 6, 8 and 10) polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimiz... Structural, electronic and mechanical properties of the nH-SiC (n = 2, 4, 6, 8 and 10) polytypes are calculated by using the first-principles calculations based on the density-functional theory approach. The optimized lattice parameters of nH-SiC are in good agreement with the experimental data. The mechanical properties, including elastic constants, bulk modulus, Young's modulus, shear modulus and Poisson's ratio, are calculated. The analysis of elastic properties indicates that the effects of n on the mechanical properties of the five nil-SiC structures have no difference. The indirect band gap relationship for the live polytypes is Ebg2H 〉 Ebg4H 〉 Ebg6H 〉 Ebg10H 〉 EbgsH. 展开更多
关键词 effects of n on Electronic and Mechanical Properties of H-Type SiC
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Effect of N+ Beam Exposure on Superoxide Dismutase and Catalase Activities and Induction of Mn-SOD in Deinococcus Radiodurans
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作者 宋道军 陈若雷 +2 位作者 邵春林 吴李君 余增亮 《Plasma Science and Technology》 SCIE EI CAS CSCD 2000年第5期491-497,共7页
Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to o... Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization. 展开更多
关键词 SOD effect of n CHC Beam Exposure on Superoxide Dismutase and Catalase Activities and Induction of Mn-SOD in Deinococcus Radiodurans Mn
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应用^(15)N自然丰度值揭示不同氮源对设施土壤氨挥发的贡献
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作者 田峪萍 双睿辰 +2 位作者 刘原庆 王立刚 孟凡乔 《植物营养与肥料学报》 CAS CSCD 北大核心 2024年第2期242-251,共10页
【目的】我国设施蔬菜生产中普遍存在着氮肥施用过量、氨气(NH_(3))挥发损失严重等问题。通过^(15)N自然丰度法,研究不同肥料类型对土壤NH_(3)挥发的影响,并定量分析其贡献率,为实现降低氮素损失的氮肥科学管理提供依据。【方法】开展为... 【目的】我国设施蔬菜生产中普遍存在着氮肥施用过量、氨气(NH_(3))挥发损失严重等问题。通过^(15)N自然丰度法,研究不同肥料类型对土壤NH_(3)挥发的影响,并定量分析其贡献率,为实现降低氮素损失的氮肥科学管理提供依据。【方法】开展为期40天的番茄盆栽培养试验,供试土壤为棕壤,未施过肥也未种植过作物,供试作物为番茄。试验设置4个处理,即不施氮肥(CK)和等量施氮(N3 g/pot)条件下单施鸡粪有机肥(M)、单施尿素(U)、有机肥半量替代尿素(MU)处理。利用被动采样器测定了土壤NH_(3)挥发速率和累积排放量,并借助^(15)N自然丰度方法估算肥料和土壤氮对NH_(3)挥发的贡献。【结果】基肥施用后3~6天内,NH_(3)挥发速率迅速增加并达到高峰,之后逐渐降低,直至第33天恢复到施肥前水平。与MU和U处理相比,M处理的净NH_(3)挥发累积量分别显著降低了60.8%和63.1%(P<0.05),MU较U处理的NH_(3)减排效果不显著(4.62%),相应的NH_(3)挥发系数分别为1.37%(U)、1.29%(MU)及0.51%(M)。施肥处理中,δ^(15)N-NH_(3)值随NH_(3)挥发的进行而迅速降低,然后逐渐增加至施肥前水平,M处理的δ^(15)N-NH_(3)均值高于MU和U处理。^(15)N同位素混合方程计算显示,在番茄生产中肥料对NH_(3)挥发的贡献比例为:M处理中鸡粪贡献30.5%,U处理中尿素贡献53.1%,MU处理中鸡粪和尿素分别贡献28.6%和56.6%。【结论】等量施氮条件下,单施鸡粪产生的NH_(3)挥发量远低于尿素,鸡粪和尿素等量氮配施对NH_(3)挥发的减排效果不显著。根据同位素分馏效应计算结果,单施鸡粪、尿素对土壤NH_(3)挥发源的贡献比例分别为30.5%、53.1%,鸡粪和尿素配施时二者对土壤NH_(3)挥发源的贡献比例分别为28.6%、56.6%,贡献比例与单施差异不大。因此,控制化肥氮施用量是减少NH_(3)挥发的关键。 展开更多
关键词 氨挥发 ^(15)n自然丰度 激发效应 设施番茄 分馏效应
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A study of temperature effect on Ta+N ion-implanted hardalloy
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作者 赵青 赵峰 +2 位作者 童洪辉 耿漫 郑永真 《Plasma Science and Technology》 SCIE EI CAS CSCD 2001年第4期897-902,共6页
Hard alloy were implanted with a dudl-ion of nitrogen and tatalum at temperature of 100℃ and 400℃ at a dose of 8×1017 ions cm-2 .Auger electron spectroscopy (AES) was used to determine the nitrogen and tantalum... Hard alloy were implanted with a dudl-ion of nitrogen and tatalum at temperature of 100℃ and 400℃ at a dose of 8×1017 ions cm-2 .Auger electron spectroscopy (AES) was used to determine the nitrogen and tantalum concentration profiles. Microhardness measurements were performed to evaluate the improvements in surface property. The thickness of implanted layers increased by about an order of magnitude when the temperature was elevated from 100℃ to 400 ℃. A higher surface hardness was also obtained in the higher temperature implantation. Scanning electron microscopy (SEM) image showed distinct microstructural changes, and X-ray diffiaction (XRD) analysis showed the presence of nitrides of tantalum and tungsten on the surface implanted. 展开更多
关键词 A study of temperature effect on Ta+n ion-implanted hardalloy Ta
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