文獻(xiàn)求翻譯
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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
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- 希成與美芽 2012-09-04 00:00:00
- so complex
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- 吞溪嘗淡裂 2012-09-01 00:00:00
- 自成立titanacyclopropane途中 cyclopropylamines只能發(fā)生在烷基鎂化 鹵化物，包含一個b氫原子，格氏試劑 沒有b氫原子似乎是Z有前途的 試劑合成的主要tert-alkylamines 從腈(方案1)。因此(1 a)、苯鎂 溴銨(2)和Ti(oi公關(guān))4被選出來 優(yōu)化反應(yīng)條件。在協(xié)議的 cyclopropylamines的合成，10 Ti(oi公關(guān))4已經(jīng) 出現(xiàn)在溶液的腈，前兩次 等價物的格氏試劑添加。因?yàn)檫@是 不是似乎Z優(yōu)合成的主要tertalkylamines， 之前的格氏試劑添加 Ti(oi公關(guān))4。2版的PhMgBr，0.1等效 鈦(oi公關(guān))4，和1相當(dāng)于(1 a)， 主要叔烷基胺8 a不是形成于所有。 與一個 克分子數(shù)相等的數(shù)量的Ti(oi公關(guān))4、胺8 a產(chǎn)生 在一個低收益率(11%)，但與1相當(dāng)于Ti(Oi - 公關(guān))4和3等價物的格氏試劑2，一個60% 產(chǎn)量得到8。 監(jiān)測的反應(yīng) aliquots引起的反應(yīng)混合物的顯示 首先添加2形成了N-magnesio的衍生物 相應(yīng)的亞胺是快速，而隨后的 第二個加入格氏試劑2需要加熱 在回流長達(dá)24小時。在四氫呋喃相反 的二乙基醚、胺8 a成立于一個非常低 產(chǎn)量，如果在所有。
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- 動了情的痞子噢 2012-09-01 00:00:00
- 我真的想說，少年，你知道要是請個翻譯這點(diǎn)要多少錢。。。
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- 詠跍k9Zh之 2012-09-01 00:00:00
- 面對你給的“侮辱性的5分”，我只想說，操伱媽逼！你丫的?。?！
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- ky394433241 2012-09-05 00:00:00
- 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. 既然在合成環(huán)丙胺的過程中， 鈦雜環(huán)丙烷的形成必須同時具有含一個b-氫原子的烷基鎂化鹵試劑，而格里納德（格氏）試劑是不含b-氫原子的，所以格氏試劑顯然是Z具發(fā)展前景成為利用腈類來合成初級叔烷基胺（方案1）的試劑；因此，（1a）、溴化苯鎂 （2）和四異丙醇鈦衍生物【Ti(Oi-Pr)4】被選作優(yōu)化反應(yīng)條件的催化劑。但在環(huán)丙胺的合成方案中，在尚未加入2份等量的格氏試劑之前，10 Ti(Oi-Pr)4就已經(jīng)存在于腈類溶液里。由于這對于初級叔烷基胺的合成似乎不是Z佳方式，因此，添加格氏試劑應(yīng)該要較早于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. 在添加兩份等量的溴化苯鎂 、0.1份等量的Ti(Oi-Pr)4和1份等量的（1a）之后，初級叔烷基胺(8a)卻根本沒有形成。如采用等摩爾量的Ti(Oi-Pr)4， 則可獲得低產(chǎn)量（11%）的8a；但如果采用1份等量的Ti(Oi-Pr)4以及3份等量的格氏試劑2（注：指溴化苯鎂 ），則可獲取60%產(chǎn)額的8a。 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. 通過對檢測反應(yīng)混液的等量試樣反應(yīng)所進(jìn)行的監(jiān)測顯示，diyi次添加溴化苯鎂 所產(chǎn)生與胺相配的N-鎂衍生物的速度很快；然而，第二次添加溴化苯鎂 時，卻需要回流加熱達(dá)24小時。 如果以四氫呋喃替換溶液，就算胺8a能夠形成，其產(chǎn)量也很低。 【英語牛人團(tuán)】
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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
451
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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
452
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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
573
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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
484
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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
469
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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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- 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
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- 納米材料英文文獻(xiàn)加翻譯
2013-06-26 12:47:02
491
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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
676
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- 求翻譯。。。。。。。。。。。
- During the preparation of the nano-products， these nano-units， such as nanoparticles， nanoclusters， nanowires and nanorods， can also self-assemble into the novel structural aggregates by several routes， including electron irradiation deposi... During the preparation of the nano-products， these nano-units， such as nanoparticles， nanoclusters， nanowires and nanorods， can also self-assemble into the novel structural aggregates by several routes， including electron irradiation deposition [19]， chemical vapor deposition [20]， laser vaporization-condensation [21]， charge transferring [22]， an organic reagent-assisted method [23]， solution-liquid-solid method [24] and catalytic vapor-liquid-solid growth [25]. With these routes， various nanoscale or microscale aggregates can demonstrate novel architectures， including tree-like， web-like， spherical， nanowire-like， network and fishbone-like aggregates. As a well-known method for producing the nanocapsules， however， arc-discharge has been rarely used to synthesize the aggregates self-assembled by the nanocapsules prepared simultaneously in arc-discharge. Nevertheless， it is possible that the arc-discharge can be developed into a new way to synthesize the aggregates. In the present work， we utilized arc-discharge technique with modified strategies， involving changing the hydrogen pressure， introducing gadolinium - aluminum alloy ingot as the anode and adjusting the elements percent of the anode according to their evaporation pressure， to synthesize a new type of nanocapsules， with intermetallic compound GdAl2 as core and amorphous Al2O3 as shell， which enlarge the family of the magnetic nanocapsules. At the same time， the regularly aligned three-dimensional macro-aggregates self-assembled by the nanocapsules without any template and catalyst were simultaneously synthesized in arc-discharge process. 展開
2008-06-09 10:41:10
402
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- 幫忙翻譯 化工文獻(xiàn) 在線等 拒絕使用自動翻譯
- 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 拒絕用自動翻譯 因?yàn)檫@個誰都會 如果有超級好用的自動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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- CAN現(xiàn)場總線的英語文獻(xiàn)和翻譯
- 朋友，你可以把你以前的can現(xiàn)場總線的英語論文和翻譯發(fā)給我嗎？60388153@qq.com... 朋友，你可以把你以前的can現(xiàn)場總線的英語論文和翻譯發(fā)給我嗎？60388153@qq.com 展開
2011-04-11 04:11:10
487
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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
432
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- 求化學(xué)翻譯
- Graphite powder (<20m)， hydrazine， ammonia， N，Ndimethylformamide (DMF)， dopamine， 0.01M phosphate buffered saline (PBS; 0.138M NaCl， 0.0027M KCl， pH 7.4)， and ascorbic acid were purchased form Aldrich and used as received. Doubly disti... Graphite powder (<20m)， hydrazine， ammonia， N，Ndimethylformamide (DMF)， dopamine， 0.01M phosphate buffered saline (PBS; 0.138M NaCl， 0.0027M KCl， pH 7.4)， and ascorbic acid were purchased form Aldrich and used as received. Doubly distilled water was used throughout the whole experiments. The data of cyclic voltammetry (CV)， differential pulse voltammetry (DPV)， and electrochemical impedance spectra were obtained with a CHI 660 electrochemical workstation (CH instruments， Austin， TX). The electrochemical cell consisted of GCE (3mm diameter， Bioanalytical Systems， Inc.) as working electrode， Ag/AgCl (Bioanalytical Systems， Inc.) as reference electrode， and platinum wire as counter electrode. The impedance data were fitted to an appropriate equivalent circuit using ZsimpWin 3.0 software (Echem Software). The Raman spectra of graphene were obtained by micro-Raman system equipped with a homemade sample stage， a monochromator (SPEX 500 M)， and a CCD camera (Roger Scientific model 7346-001) with 514.5nm wavelength laser line. Graphene was characterized by field emission scanning electron microscope (SUPRA 55VP， Carl Zeiss) and atomic force microscope (NanostationII， Surface Imaging Systems). 展開
2012-03-12 11:00:58
427
2
- 求韓語翻譯
- 3? ??然 ?? ?? ???? ? ?? ???? ??? ?? ??? ?? &... 3? ??然 ?? ?? ???? ? ?? ???? ??? ?? ??? ?? ??? ?? ??? ?? ????、 求準(zhǔn)確翻譯 PS 3元催化劑是安裝在汽車排氣管上的 展開
2012-12-19 08:48:48
450
1
- 繼續(xù)求翻譯
- Ethylacetate(Quimis，p.a.)，methanol(Quimis，p.a.)，sec-butanol(Merck，HPLCgrade)，oleicacid(Merck，extrapure)，hydrogenperoxide(Interox，70%，w/waqueoussolution)，aluminumoxideforc... Ethyl acetate (Quimis， p.a.)， methanol (Quimis， p.a.)， sec- butanol (Merck， HPLC grade)， oleic acid (Merck， extra pure)， hydrogen peroxide (Interox， 70%， w/w aqueous solution)， aluminum oxide for chromatography (Fluka， 0.05–0.15 mm)， aluminum oxide for column chromatography (Acros Organics， activated， acidic， 0.1–0.5 mm)， aluminum tri-sec-butoxide (Aldrich， 99.99%)， oxalic acid (Synth， p.a.)， di-n-butyl ether (Fluka， >99%) and soybean oil (Cargill) were used as received. The solution of anhydrous hydrogen peroxide (24%， w/w) in ethyl acetate was prepared from aqueous H2O2 (70%， w/w) in ethyl acetate by azeotropic distillation with a Dean-Stark apparatus [14] The products were identified by gas chromatography–mass spectroscopy (GC–MS) using a Hewlett-Packard 5890 gas chromatograph equipped with a AT-Wax column and interfaced with a Hewlett-Packard 5971A mass spectrometer. Helium was used as the carrier gas. A similarly equipped Hewlett-Packard5890 gas chromatograph using nitrogen as the carrier gas and a flame ionization detector was used for product quantification， with the help of calibration curves. 展開
2009-03-18 10:12:57
459
3
- 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
449
2
- 高分求高手翻譯，不要機(jī)械翻譯
- Bimetallic dendrimer-encapsulated nanoparticles(DENs)are important materials，because they have demonstrated improvement in performance compared to the monometallic DENs in many systems when they are used as catalysts.This tutorial review fo... Bimetallic dendrimer-encapsulated nanoparticles(DENs)are important materials，because they have demonstrated improvement in performance compared to the monometallic DENs in many systems when they are used as catalysts.This tutorial review focuses on the recent research advances in bimetallic DENs with respect to their synthesis，characterization，and applications as catalysts.Bimetallic DENs can be made mainly via three routes:co-complexation，sequential loading，and partial displacement.The research in bimetallic DENs has been significantly promoted by the advancement of characterization instruments.The performances of bimetallic DENs as homogeneous and heterogeneous catalysts in organic synthesis have been compared with both monometallic DENs and their physical mixtures.It is concluded that the synergistic electronic effect in bimetallic nanoparticles enhances their catalytic activities. 能翻譯多少都可以的 展開
2009-03-24 13:04:22
370
2
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