求助，英文文獻(xiàn)翻譯！
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2. Experimental 2.1 Materials Nano-CaCO3 particles (D50: 30?70 nm by TEM (Fig. 1) and BET: ca.17m2·g-1) were supplied by Shanghai Zhuoyue Nanotech Corporation. Methyl methacrylate (MMA， Shanghai Lingfeng Chemicals) was purified ... 2. Experimental 2.1 Materials Nano-CaCO3 particles (D50: 30?70 nm by TEM (Fig. 1) and BET: ca.17m2·g-1) were supplied by Shanghai Zhuoyue Nanotech Corporation. Methyl methacrylate (MMA， Shanghai Lingfeng Chemicals) was purified by distillation under reduced pressure; potassium persulphate (K2S2O8， initiator， Shanghai Lingfeng Chemicals) was of chemical grade. Silane coupling agent A174 (γ-methacryloxypropyltrimethoxysilane) was purchased from Shanghai Yaohua Factory. Polyvinylchloride (PVC， WS-1000S) was supplied by Shanghai Chlor-Alkali Chemical Co.， Ltd. Fig. 1 Morphology of untreated CaCO3 nanoparticles. Fig. 2 Morphology of PMMA-coated CaCO3 nanoparticles. 2.2 PMMA emulsion polymerization on CaCO3 nanoparticles 2.2.1 Surface silanation of nano-CaCO3 particles The nano-CaCO3 particles were homogeneously dispersed in ethanol (solid content 20%) by a sonication dispersion equipment. The slurry was then heated to 80°C with stirring， and the silane coupling agent A174 (5%， calculated based on the weight of nano-CaCO3 particles) was added into the slurry. After the slurry was stirred for 120 min at 80°C， it was filtered and the filter cake was then dried at 120°C in low vacuum for 120 min to obtain silanated CaCO3 powders. 展開
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- ____邁卡維 2011-05-22 00:00:00
- 2. 實(shí)驗(yàn) 2.1 材料 納米碳酸鈣微粒（D50: 用TEM（透視電子顯微鏡）法為30−70毫微米（見圖1），用BET法為ca.17m2•g-1）由上海zhuo越納米技術(shù)公司提供。甲基丙烯酸甲酯（MMA，上海凌鋒化工廠）用蒸餾法在減壓條件下提純；過硫酸鉀（K2S2O8，引發(fā)劑，上海凌鋒化工廠）是化學(xué)級的。硅烷偶聯(lián)劑A174（γ-甲基丙烯酰氧基丙基三甲氧基硅烷）購自上海耀華工廠。聚氯乙烯（PVC，WS-1000S）由上海氯堿化工有限公司提供。 圖1 未經(jīng)處理的碳酸鈣納米材料的形態(tài)結(jié)構(gòu) 圖2 表面包覆了聚甲基丙烯酸甲酯（PMMA）的碳酸鈣納米材料的形態(tài)結(jié)構(gòu) 2.2 PMMA乳液對碳酸鈣納米材料的聚合作用 2.2.1納米碳酸鈣微粒的表面硅烷化 通過一臺超聲散布設(shè)備的處理，納米碳酸鈣微粒在乙醇中均勻分散（含固率20%）。料漿在攪拌中被加熱到80°C，然后將硅烷偶聯(lián)劑A174（5%，按納米碳酸鈣微粒的重量計(jì)算）加入料漿。料漿在80°C的溫度下被攪拌120分鐘后，對其進(jìn)行過濾，過濾后產(chǎn)生的濾餅在低真空中以120°C的溫度干燥120分鐘以獲得硅烷化碳酸鈣粉末。
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- 莊1914 2011-05-17 00:00:00
- 2. 實(shí)驗(yàn) 2.1 材料 納米碳酸鈣微粒（D50: 用TEM（透視電子顯微鏡）法為30−70毫微米（見圖1），用BET法為ca.17m2•g-1）由上海zhuo越納米技術(shù)公司提供。甲基丙烯酸甲酯（MMA，上海凌鋒化工廠）用蒸餾法在減壓條件下提純；過硫酸鉀（K2S2O8，引發(fā)劑，上海凌鋒化工廠）是化學(xué)級的。硅烷偶聯(lián)劑A174（γ-甲基丙烯酰氧基丙基三甲氧基硅烷）購自上海耀華工廠。聚氯乙烯（PVC，WS-1000S）由上海氯堿化工有限公司提供。 圖1 未經(jīng)處理的碳酸鈣納米材料的形態(tài)結(jié)構(gòu) 圖2 表面包覆了聚甲基丙烯酸甲酯（PMMA）的碳酸鈣納米材料的形態(tài)結(jié)構(gòu) 2.2 PMMA乳液對碳酸鈣納米材料的聚合作用 2.2.1納米碳酸鈣微粒的表面硅烷化 通過一臺超聲散布設(shè)備的處理，納米碳酸鈣微粒在乙醇中均勻分散（含固率20%）。料漿在攪拌中被加熱到80°C，然后將硅烷偶聯(lián)劑A174（5%，按納米碳酸鈣微粒的重量計(jì)算）加入料漿。料漿在80°C的溫度下被攪拌120分鐘后，對其進(jìn)行過濾，過濾后產(chǎn)生的濾餅在低真空中以120°C的溫度干燥120分鐘以獲得硅烷化碳酸鈣粉末。
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- ttnn123456 2011-05-17 00:00:00
- 2.實(shí)驗(yàn) 2.1材料 納米碳酸鈣顆粒（D50的：30-70 nm的透射電鏡（圖1），TEM ca.17m2·g-1）由上海卓悅奈米科技公司配置。甲基丙烯酸甲酯(MMA，上海靈峰化學(xué)品)純化減壓蒸餾，(過硫酸鉀、引發(fā)劑類型）上海靈峰化學(xué)品。硅烷偶聯(lián)(γ-methacryloxypropyltrimethoxysilane代理A174)是從上海耀華廠購買的。薄膜(PVC、WS-1000S)由上海氯堿化工有限公司提供等。 圖1未經(jīng)處理的碳酸鈣納米粒子形貌。 圖2形態(tài)結(jié)構(gòu)的PMMA-coated碳酸鈣納米粒。 2.2 碳酸鈣 PMMA乳液聚合納米粒子 2.2.1 注意 silanation nano-CaCO3表面的顆粒nano-CaCO3粒子均勻分散，用無水乙醇超聲分散設(shè)備（固含量20％）。然后加熱水泥漿是80°C，硅烷偶聯(lián)劑A174(5%，計(jì)算基于nano-CaCO3顆粒的重量)添加到泥漿，攪拌，120分鐘后，濾餅過濾并在120°C干燥后，低真空獲得碳酸鈣粉體。
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- 598072770 2011-05-25 00:00:00
- 2. Experimental 實(shí)驗(yàn) 2.1 Materials 2.1 材料 Nano-CaCO3 particles (D50: 30−70 nm by TEM (Fig. 1) and BET: ca.17m2•g-1) were supplied by Shanghai Zhuoyue Nanotech Corporation. Methyl methacrylate (MMA， Shanghai Lingfeng Chemicals) was purified by distillation under reduced pressure; potassium persulphate (K2S2O8， initiator， Shanghai Lingfeng Chemicals) was of chemical grade. Silane coupling agent A174 (γ-methacryloxypropyltrimethoxysilane) was purchased from Shanghai Yaohua Factory. Polyvinylchloride (PVC， WS-1000S) was supplied by Shanghai Chlor-Alkali Chemical Co.， Ltd. 納米碳酸鈣粒子（中值粒徑：透視電子顯微鏡測定為30-70納米 （圖1）且用BET比表面積儀測定Ca的比表面積為17 m²/g）由上海Zhuoyue 納米技術(shù)公司提供。MMA （上海Lingfeng化工生產(chǎn)）用減壓蒸餾法提純；過硫酸鉀（K2S2O8，引發(fā)劑，上海Lingfeng 化工）是化學(xué)級別的。硅烷偶聯(lián)劑A174（γ-(甲基丙烯酰氧)丙基三甲氧基硅烷）從上海Yaohua 廠采購。聚氯乙烯（PVC，WS-1000S）由上海氯堿化工股份有限公司供應(yīng)。 Fig. 1 Morphology of untreated CaCO3 nanoparticles. 圖1未經(jīng)處理的碳酸鈣納米材料的形態(tài)結(jié)構(gòu) Fig. 2 Morphology of PMMA-coated CaCO3 nanoparticles. 圖2 表面涂覆了（PMMA）的碳酸鈣納米材料的形態(tài) 2.2 PMMA emulsion polymerization on CaCO3 nanoparticles 2.2.1 Surface silanation of nano-CaCO3 particles The nano-CaCO3 particles were homogeneously dispersed in ethanol (solid content 20%) by a sonication dispersion equipment. The slurry was then heated to 80°C with stirring， and the silane coupling agent A174 (5%， calculated based on the weight of nano-CaCO3 particles) was added into the slurry. After the slurry was stirred for 120 min at 80°C， it was filtered and the filter cake was then dried at 120°C in low vacuum for 120 min to obtain silanated CaCO3 powders. 2.2 碳酸鈣納米粒子上的PMMA乳液聚合作用 2.2.1納米碳酸鈣粒子的表面硅烷化處理 納米碳酸鈣粒子通過聲波降解擴(kuò)散裝置均勻散布在乙醇（固含量為20%）中。邊攪動(dòng)邊加熱料漿至80°C，然后在料漿中加入硅烷偶聯(lián)劑A174（5%，基于納米碳酸鈣粒子的重量來計(jì)算）。在80°C溫度下攪動(dòng)120分鐘后，過濾料漿，將濾餅在120°C低真空環(huán)境中烘干120分鐘，從而得到硅烷化的碳酸鈣粉末。 注： 1，Zhuoyue 納米技術(shù)公司 ， Lingfeng化工，Yaohua廠為工廠或公司名，不確定，未翻譯。而Shanghai Chlor-Alkali Chemical Co.， Ltd 上海氯堿化工股份有限公司，確定，所以翻譯了。 2，sonication dispersion equipment 譯作聲波降解擴(kuò)散裝置，不敢確定。請斟酌使用。
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- 求助，英文文獻(xiàn)翻譯！
- 2. Experimental 2.1 Materials Nano-CaCO3 particles (D50: 30?70 nm by TEM (Fig. 1) and BET: ca.17m2·g-1) were supplied by Shanghai Zhuoyue Nanotech Corporation. Methyl methacrylate (MMA， Shanghai Lingfeng Chemicals) was purified ... 2. Experimental 2.1 Materials Nano-CaCO3 particles (D50: 30?70 nm by TEM (Fig. 1) and BET: ca.17m2·g-1) were supplied by Shanghai Zhuoyue Nanotech Corporation. Methyl methacrylate (MMA， Shanghai Lingfeng Chemicals) was purified by distillation under reduced pressure; potassium persulphate (K2S2O8， initiator， Shanghai Lingfeng Chemicals) was of chemical grade. Silane coupling agent A174 (γ-methacryloxypropyltrimethoxysilane) was purchased from Shanghai Yaohua Factory. Polyvinylchloride (PVC， WS-1000S) was supplied by Shanghai Chlor-Alkali Chemical Co.， Ltd. Fig. 1 Morphology of untreated CaCO3 nanoparticles. Fig. 2 Morphology of PMMA-coated CaCO3 nanoparticles. 2.2 PMMA emulsion polymerization on CaCO3 nanoparticles 2.2.1 Surface silanation of nano-CaCO3 particles The nano-CaCO3 particles were homogeneously dispersed in ethanol (solid content 20%) by a sonication dispersion equipment. The slurry was then heated to 80°C with stirring， and the silane coupling agent A174 (5%， calculated based on the weight of nano-CaCO3 particles) was added into the slurry. After the slurry was stirred for 120 min at 80°C， it was filtered and the filter cake was then dried at 120°C in low vacuum for 120 min to obtain silanated CaCO3 powders. 展開
2011-05-16 00:26:36
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- 求助，英文文獻(xiàn)翻譯~
- PMMA has good compatibility with PVC due to specific interaction of a hydrogen bonding type between carbonyl groups (C=O) of PMMA and hydrogen from (CHCl) groups of PVC (Belhaneche-Bensemra et al.， 2002; Ramesh et al.， 2002). Zhou et al... PMMA has good compatibility with PVC due to specific interaction of a hydrogen bonding type between carbonyl groups (C=O) of PMMA and hydrogen from (CHCl) groups of PVC (Belhaneche-Bensemra et al.， 2002; Ramesh et al.， 2002). Zhou et al. (2001) studied the relationship between the coating thickness of PMMA on the surface of talc and mechanical properties of PMMA-g-talc/PVC composites， and found that there existed a critical thickness. Xie (2001) found that the PMMA coating on talc improved the dispersion of talc in the PVC matrix and enhanced the interfacial adhesion between talc and PVC. There appears to be a critical coating thickness of PMMA on the talc surface for optimum toughening. Quan et al. (2002) reported improved toughness and intension of the PVC composites filled with CaCO3/ACR core-shell complex particles prepared by in-situ emulsion polymerization of acrylic ester. In the present work， PMMA coated on the surface of CaCO3 nanoparticles by in-situ emulsion polymerization was characterized by FT-IR and 1H-NMR. The effects of PMMA thickness and particle fraction on the mechanical properties of PMMA-coated CaCO3 /PVC nanocomposites were also investigated. 展開
2011-05-16 04:20:15
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- 求翻譯英文文獻(xiàn)
- 2.2. Material Characterizations. A field emission scanning electron microscope (SEM， JEOL 6701F) was used to investigate the morphologies， particle sizes of the samples. Transmission electron microscopy and elemental compositions of the ... 2.2. Material Characterizations. A field emission scanning electron microscope (SEM， JEOL 6701F) was used to investigate the morphologies， particle sizes of the samples. Transmission electron microscopy and elemental compositions of the samples were determined by JEM-2100F (JEOL) coupled with an energy-dispersive X-ray spectroscopy (EDX， Phoenix) system. Wide-angle and low-angle X-ray powder diffraction (XRD) of the as-obtained samples were recorded on a Rigaku D/max-2500 with Cu Kα radiation (λ = 1.540 56 ?) operated at 40 kV and 200 mA. Raman measurements were performed using a DXR from Thermo Scientific with a laser wavelength of 532 nm. To calculate the pore size distribution and pore volumes， the nitrogen absorption and desorption isotherms were measured at 77.3 K with an Autosorb-1 specific surface area analyzer from Quantachrome. The content of N in N-doped porous carbon was determined by NHC elemental analysis using Flash EA 1112. Thermogravimetric (TG) analysis of S/C composite was performed on TG/DTA 6300 in an N2 flow to obtain the S content in the composite. A four-contact method was applied to measure the powder electronic conductivity of porous carbons. The powder sample was pressed to disk at 4 MPa with two stainless-steel plungers， whose resistance was measured by a Keithley 2400 digital multimeter in fourwire mode. The conductivity of the sample was calculated according to the resistance and the size of the disk. Information of the surface elements was obtained by X-ray photoelectron spectroscopy (XPS) performed on the Thermo Scientific ESCALab 250Xi using 200 W monochromatic Al Kα radiation. The 500 μm X-ray spot was used for XPS analysis. The base pressure in the analysis chamber was about 3 × 10?10 mbar. All reported data of XPS binding energy are calibrated based on the hydrocarbon C 1s line at 284.8 eV from adventitious carbon. Spectra were fitted with Lorentzian?Gaussian functions and smart background using Thermo Avantage software. 展開
2014-12-28 15:14:51
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2013-06-26 12:47:02
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- 通信方面的英文文獻(xiàn)翻譯??！
- 以下是文獻(xiàn)的一部分，愿意幫忙的高手留下郵箱，我把文件發(fā)給你，若能完成，加分：SpatialCompressiveSensingApproachForFieldDirectionalityEstimation.I.INTRODUCTIONVarietyoft... 以下是文獻(xiàn)的一部分，愿意幫忙的高手留下郵箱，我把文件發(fā)給你，若能完成，加分： Spatial Compressive Sensing Approach For Field Directionality Estimation. I. INTRODUCTION Variety of techniques for field directionality estimation were studied in literature [1]-[5]. Thus， a theoretical analysis of the relationship between the hydrophone array output and the noise field was conducted in [1]-[5]. The developed techniques were based on the array beamformer output or the crossspectral matrix between outputs of array elements [4]-[5]. The problem of a field directionality estimation in ocean， using horizontal line towed array was also addressed in literature [5]- [8]. Recently， problems of direction of arrival and field directionality estimation for moving sensors arrays have attracted renewed interest [9]-[12]. It was shown that an array motion can improve an array performance assuming temporal coherence of successive samples [10]-[11]. In [12]， the wavefield sampling method that exploits the linear relationship between the noise field and the collection of beamformer outputs over various array orientations was proposed. It was shown that the wavefield sampling (WS) method outperforms other tested methods. This algorithm was implemented via the recursive estimation method and its convergence to the unique solution was promised for a specific set of array orientations and beamformer look directions. However， a method for a proper array orientation and beamformer look direction sequence selection remains an open question. The quality of the field directionality estimation is determined by the angular resolution. The higher angular resolution is， the more accurate estimation of the far field sources， and better detection performance can be achieved. One of fundamental relations in the array signal processing is that the angular resolution is directly proportional to the number of the array elements [13]. This relation motivates the desire for longer arrays that can achieve higher resolution. Unfortunately， the requirement contradicts the implementation and installation limitations that motivate shorter arrays. Moreover， implementation of longer arrays for maneuvering platforms such as unmanned underwater vehicles (UUV) can even be impossible [14]. These contradictions motivate the quest for alternative array signal processing methods. Usually， the field directionality is modeled as a finite set of strong far-field narrow-band sources and an isotropic lowpower noise [1]. In this work， the model of the field directionality is adopted in the following way. First， the bearing angle space is uniformly sampled into a large number of discrete angles. Next， it is assumed that ether the high energy that corresponds to the far-field strong sources or the low-energy that corresponds to the isotropic noise is received at the sensor array from every of these discrete azimuth angles. 展開
2010-01-17 08:59:13
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- 誰能幫我翻譯一下這段英文文獻(xiàn)啊
- Fig. 1 shows that diamond particles are dispersed in the copper matrix. Since the diamond particles are easy to be stripped off during mechanical polishing， small pits are left on the surface of samples. When the samples were analyzed b... Fig. 1 shows that diamond particles are dispersed in the copper matrix. Since the diamond particles are easy to be stripped off during mechanical polishing， small pits are left on the surface of samples. When the samples were analyzed by electron probe for carbon， the particles displayed high carbon peaks， as shown in Fig. 2. Fig. 3 exhibits the analyzed result for extracted product of the copper–diamond composite by X-ray diffraction (XRD) analysis. It is shown that three dif- fraction peaks exist， shown as A， B and C， respectively. The interplanar distances corresponding to the three peaks and standard ones for diamond are compared in Table 1. The measured values of the interplanar distances are in good agreement with the standard ones， demon- strating that the extracted product should be the carbon in diamond state. Fig. 4(a) gives a TEM micrograph showing distribution and morphology of diamond particles (indicated as A， B， and C) in the copper–diamond composite. The calibration of interplanar distance for diffraction rings in Fig. 4(b) was given in Table 2. Compared to Table 1， it is also demon- strated that the calibrated interplanar distances for the diffraction rings conform to the standard ones of diamond. Therefore， it is believed that the graphitization of diamond particles hardly occurs after sintering at 1150–1220 K in the copper–diamond composite. Although diamond is a metastable allotropic modifica- tion of carbon， the graphitization of diamond particles in the copper–diamond composite did not occur， or the degree of graphitization was too small to be found. It is believed that the beginning temperature of graphi- tization would be associated with the purity of diamond powders. The impurities such as some metallic elements reduce the beginning temperature of diamond graphitiza- tion. When diamond is fabricated by the static synthesis method， Fe and Ni are often used as catalysts and are present in diamond as impurities to decrease the beginning temperature of graphitization [6]. It is understandable that both for the graphitization and its reverse reactions， their activation energies can be decreased by catalytic agents. Compared with the diamond fabricated by static synthesis， the diamond powders prepared by explosion method do not contain metallic impurities， thus leading to an obvious increase in the beginning temperature of graphitization. Hence， the detonation synthetic diamond might be more resistant to graphitization and probably suitable for the electric contact materials. 展開
2011-03-22 08:43:56
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- 文獻(xiàn)求翻譯
- Since the formation of a titanacyclopropane en route to cyclopropylamines can only occur with alkylmagnesium halides that contain a b-hydrogen atom， Grignard reagents without b-hydrogens appeared to be the most promising reagents for th... Since the formation of a titanacyclopropane en route to cyclopropylamines can only occur with alkylmagnesium halides that contain a b-hydrogen atom， Grignard reagents without b-hydrogens appeared to be the most promising reagents for the synthesis of primary tert-alkylamines from nitriles (Scheme 1). Thus propionitrile (1a)， phenylmagnesium bromide (2) and Ti(Oi-Pr)4 were chosen to optimize the reaction conditions. In the protocol for the synthesis of cyclopropylamines，10 Ti(Oi-Pr)4 is already present in the diethyl ether solution of a nitrile， before two equivalents of the Grignard reagent are added. As this did not appear to be optimal for the synthesis of primary tertalkylamines， the Grignard reagent was added before Ti(Oi-Pr)4. With 2 equivalents of PhMgBr， 0.1 equivalent of Ti(Oi-Pr)4， and 1 equivalent of propionitrile (1a)， the primary tert-alkylamine 8a was not formed at all. With an equimolar quantity of Ti(Oi-Pr)4， the amine 8a was produced in a low yield (11%) but with 1 equivalent of Ti(Oi- Pr)4 and 3 equivalents of the Grignard reagent 2， a 60% yield of 8a was obtained. Monitoring of the reaction by workup of aliquots of the reaction mixture showed that the first addition of 2 to form the N-magnesio derivative of the corresponding imine was rapid， whereas the subsequent second addition of the Grignard reagent 2 required heating under reflux for up to 24 hours. In tetrahydrofuran instead of diethyl ether， the amine 8a was formed in a very low yield， if at all. 展開
2012-08-31 01:19:05
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- 求翻譯文獻(xiàn)
- Anionsarecommonlyfoundintheenvironmentandbiologicalsystems.Forinstance，fluorideiswidelyusedindentalcareapplicationsandexhibitsinhibitionofcertainenzymefunctions.1Inadditi... Anions are commonly found in the environment and biological systems. For instance， fluoride is widely used in dental care applications and exhibits inhibition of certain enzyme functions.1 In addition to playing a central role in biological regulation， chloride is also a major groundwater contaminant that can corrode steel and concrete.2 Thyroid hormone synthesis largely determines iodine content.3 Acetate is a possible tracer for malignancies and has been extensively investigated in prostate cancer and its metastases.4 Phosphate ion is biologically and environmentally significant.5 Cyanide exerts adverse effects on human health as well as environment at low concentrations. Determining anions concentration is thus of primary concern in many areas， including food processing， industry， and clinic analysis.6 However， hydrophilic anions， such as F- and Cl-， form strong hydrogen bonds with protic solvents. Therefore， developing fluorescent probes based on electrostatic interactions for anions functioning in polar protic solvents is both challenging and currently infeasible. 展開
2009-12-15 12:42:12
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- 翻譯段文獻(xiàn)麻煩
- Eventhoughfluorescentprobesforcopperionhavebeenextensivelyexploredowingtobiologicalsignificanceofthismetalion，4therearestillonlyafewexamplesof“off-on”typesensorsavailab... Even though fluorescent probes for copper ion have been extensively explored owing to biological significance of this metal ion，4 there are still only a few examples of “off-on” type sensors available in aqueous systems.5 Furthermore， only a few ratiometric fluorescent probes for Cu2+ have been found in the literature due the fluorescence quenching nature of paramagnetic Cu2+，6 and most of them were working only in pure organic solvents. Ratiometric fluorescent measurements observe changes in the ratio of the intensities of the emission at two wavelengths. Thus， ratiometric fluorescent sensors have an important feature that they can be used to evaluate the analyte concentration and provide built-in correction for environmental effects. On the other hand， rhodamine derivatives are nonfluorescent and colorless， whereas ring-opening of the corresponding spirolactam gives rise to strong fluorescence emission and a pink color. Recently， a spirolactam (nonfluorescent) to ringopened amide (fluorescent) process was utilized for the detection of metal ions.5a，b，d，e，7 We introduced rhodamine fluorophore onto the pyrene moiety， which was utilized as a selective fluorescent and colorimetric sensor for Cu2+ in aqueous solution. Among the various metal ions， the chemosensor PRC displayed highly selective ratiometric changes upon the addition of Cu2+. As expected， the pyrene moiety served successfully as a source of these ratiometric changes. As far as we are aware， PRC is the first ratiometric sensor based on rhodamine derivative. For comparison， pyrene-based compound P4 was synthesized to test the fluorescence change with Cu2+. 展開
2009-12-23 07:28:19
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- 翻譯以下英文：
- The standard error of the mean (SEM) is a measure of how far your sample mean is likely to be from the true population mean. The SEM is calculated by this equation:SEM=SD/N. With large samples， the SEM is always small. By itself， the SEM i... The standard error of the mean (SEM) is a measure of how far your sample mean is likely to be from the true population mean. The SEM is calculated by this equation:SEM=SD/N. With large samples， the SEM is always small. By itself， the SEM is difficult to interpret. It is easier to interpret the 95% confidence interval， which is calculated from the SEM. 展開
2007-11-15 02:56:39
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- 求助翻譯
- 問題一：請問“在GF254硅膠板上，取樣點(diǎn)板，在254nm紫外光下觀察結(jié)果”這句話該如何翻譯？ZD是不知道“取樣點(diǎn)板”怎么翻譯問題二：麻煩高手幫忙翻譯一下2Results2.1柱色譜分離結(jié)果The... 問題一： 請問 “在GF254硅膠板上，取樣點(diǎn)板，在254 nm紫外光下觀察結(jié)果” 這句話該如何翻譯？ ZD是不知道“取樣點(diǎn)板”怎么翻譯 問題二：麻煩高手幫忙翻譯一下 2 Results 2. 1 柱色譜分離結(jié)果 The results of separation by column chromatography 柱色譜分離過程中，氯仿∶甲醇95∶5和90∶10洗脫出來的流分經(jīng)過反復(fù)的硅膠柱色譜分離純化得到組分C3。 2. 2 薄層色譜檢測結(jié)果 The results of Thin-layer chromatography. 組分C3在GF254硅膠板上展開后，可在254nm紫外燈下直觀觀測為單點(diǎn)，見圖1。 2. 3 GX液相色譜分析和制備單體化合物 對組分C3 進(jìn)行GX液相制備，色譜圖顯示有4個(gè)色譜峰(見圖2) ，分離效果較好，收集4個(gè)單峰組分，得到4個(gè)化合物1～4，對以上4個(gè)化合物進(jìn)行GX液相分析，均為單峰，見圖3～4。 3 化合物的結(jié)構(gòu)鑒定 通過制備液相收集得到4個(gè)化合物，對其中3個(gè)化合物進(jìn)行結(jié)構(gòu)鑒定: 化合物1， 淡黃色晶體， UV λmax nm (logε) : 248 nm。E IMS，m / z 501. 3 [M + 1 ] + ，分子量為500?；衔?氫譜顯示7個(gè)甲基信號;δ1. 02， 0. 93， 0. 78 ( each 3H， s) ， 0. 89 ( 3H， d， J =6. 4Hz) ， 1. 23， 1. 25 ( each 3H， d， J = 5. 2Hz) ， 1. 22(3H， s) ，一個(gè)連氧碳上的氫信號δ3. 23 (1H， dd， J= 10 Hz) ，符合三萜化合物的結(jié)構(gòu)，可以證明化 合物1為三萜類化合物。 化合物2， UV λmax nm ( logε) : 250 nm。E IMS，m / z 515. 3 [M + 1 ] + ，分子量為514?；衔?的氫譜顯示7個(gè)甲基信號δ0. 77， 0. 94， 1.01， 1. 22， 1. 23 (3H， s) ， 0. 82 (3H， d， 10. 2 Hz) ，一個(gè)連氧碳上的氫信號δ3. 22 ( 1H， dd， J = 10. 5Hz) ，一個(gè)甲氧基上的氫信號δ3. 66 (3H， s) ，符合三萜化合物的結(jié)構(gòu)，可以證明化合物2為三萜化合物。 化合物3， UV λmax nm ( logε) : 254 nm。EIMS，m / z 531. 2 [M + 1 ] + ，分子量為514?；衔? 的氫譜(見附錄)顯示7 個(gè)甲基信號δ0.78， 0. 82， 0. 87， 1. 03， 1. 24， 1. 31 ( 3H， s) ， 1. 17(3H， d， 6. 6 Hz) ，一個(gè)乙?；系臍湫盘?. 10(3H， s) ，一個(gè)甲氧基團(tuán)的氫信號3. 68 (3H， s) ，符合三萜化合物的結(jié)構(gòu)，可以證明化合物3為三萜化合物。 化合物4結(jié)構(gòu)較復(fù)雜，不能確定是三萜化合物。 二樓的辛苦了，非常感謝你的回答。不過好像沒有明白我的意思，而且有g(shù)oogle之嫌。 展開
2009-05-07 18:35:24
770
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- 環(huán)境英語文獻(xiàn)翻譯 急用
- Thereisagrowinginterestindeterminingmercury(Hg)levelsinthemarineenvironmentaswellasinfishforhumanconsumption.Methylmercury(MeHg)inparticularisthemosttoxicandbioaccumulati... There is a growing interest in determining mercury(Hg) levels in the marine environment as well as in fish for human consumption. Methyl mercury(Me Hg)in particular is the most toxic and bioaccumulative form of mercury in food webs and it is the predominant chemical form making up 80%-90% of the total mercury present in fish muscle tissue.Hence，fish and other organisms at the end of the food chain constitute the major source of MeHg in the human . As outcome of this risk，MeHg has been classically monitored in fish， and methodologies for mercury speciaion have increased significantly since the early 1990s. Currently， microwave-assisted extraction (MAE) has provided an efficient alternative strategy to conventional techniques for solvent extraction of a large amount of organometals compounds.The analytical techniques most frequently applied for Hg speciation analysis involve GC(GasChromatography) ， GC-CICP-MS(Gas Chromatography -CInductively Coupled Plasma Mass Spectrometry) supercritical fluids chromatography (SFC)，ion chromatograph(IC)， HPLC-CCVAAS(High Performance Liqui Chromatography-Cold Vapor Atomic Absorption Spectrometry) or ICP-MS systems .Several authors recommended a back-extraction of mercury species from organic solvents to cysteine or sodium thiosulphate aqueous solutions .Because MeHg is the most common organomercury compound in biological materials ，here we offer a new simple and cost-effective method to determine MeHg. Basically， this method combines the microwave assisted extraction followed by clean-up with cysteine acetate solution and MeHg quantification by a direct mercury analyzer (DMA). 展開
2009-05-18 11:22:05
392
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- 求達(dá)人 翻譯下英文文獻(xiàn) 關(guān)于 光系統(tǒng)Ⅱ和除草劑 通順Z重要
- PhotosystemIIisthemulti-enzymaticchlorophyll-proteincomplex(water-plastoquinoneoxido-reductase)locatedinthethylakoidmembraneofalgae，cyanobacteriaandhigherplants.Itisanint... Photosystem II is the multi-enzymatic chlorophyll-protein complex (water-plastoquinone oxido-reductase) located in the thylakoid membrane of algae， cyanobacteria and higher plants. It is an integral part of the electron transport chain that catalyses primary charge separation. This protein complex consists of over 25 polypeptides， which make up a light-harvesting chlorophyll protein complex (LHCII)， a reaction centre and the water-splitting system， also called the oxygen evolving complex (OEC). The PSII complex also contains the target site of the most widely used photosynthetic herbicides."^ The preparation of a biosensor for the detection of polluting compounds is based on the specific characteristics of PSII. Under illumination PSII drives electron transfer which is inhibited by specific chemical compounds (e.g.， herbicides). Thus， the photosynthetic membrane isolated firom higher plants and photosynthetic micro-organisms， immobilised and stabilised， will serve as the biosensor biomediator. The effect of compounds that alter or inhibit photosynthetic activity， measured as oxygen evolution， electron transport or fluorescence can then be translated and monitored by amperometric or optical systems. Recent experiments that were performed by our this team resulted in amperometric， potentiometric， optical biosensors for herbicides based on isolated and immobilised PSII particles exhibiting stable biological material and a highly sensitive monitoring response (limit of detection in the nanomolar range and for diuron herbicide in the picomolar range).^'^ However， the system is specific to photosynthetic herbicides but not very selective since several classes of compounds (herbicides represented by triazines， ureas， diazines， phenols) can bind to proteins of the PSII complex， most of them to the Dl protein of the reaction centre. 展開
2010-04-30 16:23:35
430
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- 幫忙翻譯一段關(guān)于方酸染料合成的的英文文獻(xiàn) 急急急
- Synthesisofsquarainedyeswasreportedatleastin1966。Theyarederivedfromsquaricacidwhichundergoesanelectrophilicaromaticsubstitutionreactionwithananilineoranotherelectronrich... Synthesis of squaraine dyes was reported at least in 1966 。They are derived from squaric acid which undergoes an electrophilic aromatic substitution reaction with an aniline or another electron rich derivative to form a highly conjugated product with extensive charge distribution. For instance， squaraine dyes are also formed via reaction of squaric acid or its derivatives with so-called "methylene bases" like 2-methyl-indolenines， 2-metyl-benzthiazoles or 2-methyl-benzo-selenazoles. Indolenine-based squaraines combine good photostability including high quantum yields when bound to proteins and reactive versions of these dyes are commonly used as fluorescent probes and labels for biomedical applications . 展開
2011-05-20 09:09:32
331
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- 波譜英文文獻(xiàn)在哪里下載?
2010-12-08 02:02:14
441
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- 化工類英文科技文獻(xiàn)譯中文
- There is a fair body of literature concerning the electroreduction of glucose. This has been reviewed by Fedoronko. He divided his review into the polarographic work and that done on solid electrodes. The polarographic studies form a cohere... There is a fair body of literature concerning the electroreduction of glucose. This has been reviewed by Fedoronko. He divided his review into the polarographic work and that done on solid electrodes. The polarographic studies form a coherent picture， in which the experimentally observed data， which take the form of a plateau， not diffusion controlled， are explained in terms of a rate-determining step of mutarotation from the cyclic (inactive) form of the sugar to the linear (electroactive) form. The process is known to be both acid and base catalyzed， and has been reviewed by Capon. It is generally assumed that no hydrogen evolution takes place in the polaro- graphic plateau region. 翻譯通順有加分！謝謝大家！不需要機(jī)器翻譯的！ 展開
2009-03-05 08:04:04
354
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- 數(shù)據(jù)采集的英文怎么翻譯？
2010-07-05 09:53:28
414
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- 翻譯英文~專業(yè)類的
- Whilegraphene，acarbon-basedtwo-dimensionalnanomaterials，hasreceivedanupsurgeofinterest，[1]self-assemblyofsmallorganicandorganometallicmoleculesinto2Dnanostructurescouldal... While graphene， a carbon-based two-dimensional nanomaterials， has received an upsurge of interest，[1] self-assembly of small organic and organometallic molecules into 2D nanostructures could also be harnessed to develop new classes of functional supramolecular nanomaterials.[2] In principle， quasi-2D lamellae or nanosheets are planar structures having a thickness less than 100 nm and lateral dimensions a few orders of magnitude greater than their thickness. Control over the bilateral intermolecular noncovalent interactions is anticipated to organize small molecules into regular 2D nanostructures， which has been a formidable challenge yet to be achieved. Recently， Shelnutt and co-workers obtained discrete porphyrin nanosheets reprecipitated from their solutions;[3] Sathish and co-workers constructed hexagonal C60 nanosheets using a liquid–liquid interfacial precipitation method;[4] the groups of Yao[5] and Hu[6] prepared singlecrystalline nanosheets of polycyclic aromatics using a surfactant- assisted reprecipitation and a physical vapor transporting method， respectively; and Zhang and co-workers suggested that molecules with intramolecular charge-transfer dipole moments could be grown into quasi-2D nanostructures.[7] Moreover， some amphiphiles and organogelators were found to self-organize into sheet-like nanostructures in contact with solvents.[8] Despite these advances， templateand surfactant-free synthesis of free-standing， crystalline， and optoelectronically active nanosheets from small molecules remains elusive. 展開
2010-03-06 01:33:12
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- 幫忙翻譯 化工文獻(xiàn) 在線等 拒絕使用自動(dòng)翻譯
- Nano-sized Beta zeolites， with a crystal size of 80–100 nm， were synthesized via surface wet method. The nano-sized Hbeta zeolites exhibit much higher activity and stability in the Friedel–Crafts acylation of anisole and toluene with acet... Nano-sized Beta zeolites， with a crystal size of 80–100 nm， were synthesized via surface wet method. The nano-sized Hbeta zeolites exhibit much higher activity and stability in the Friedel–Crafts acylation of anisole and toluene with acetic anhydride than theconventional zeolites of largeparticle size.The smallcrystalsize of nano-sized zeolitesmay bringon more accessible activesites and then enhance the catalytic activity. The exposed pore openings in nano-sized zeolites allow a fast desorption of heavy products from the catalyst and can then reduce the occupancy of active sites by the adsorption of products ，this can then alleviate the catalyst deactivation and improve the catalyst stability deactivation and improve the catalyst stability. 急用 在線等 拒絕用自動(dòng)翻譯 因?yàn)檫@個(gè)誰都會(huì) 如果有超級好用的自動(dòng)在線翻譯或軟件也可以推薦 展開
2009-05-31 04:30:04
457
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- 請問你能找到關(guān)于蛋白質(zhì)純化與分離的英文文獻(xiàn)及翻譯么
2015-01-04 20:46:08
553
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