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pxyqcqk7520rm 2012-07-21 08:11:42 332  瀏覽

  • 1.α-苯乙胺的微波合成研究2.以苯乙胺為母體的亞胺配合物的合成及結(jié)構(gòu)3.手性物α-苯乙胺的制備和分析研究4.超聲輻射Pd/C催化合成α-苯乙胺5.2，5-二甲氧基苯乙胺鹽酸鹽合成新工藝... 1.α-苯乙胺的微波合成研究 2.以苯乙胺為母體的亞胺配合物的合成及結(jié)構(gòu) 3.手性物α-苯乙胺的制備和分析研究 4.超聲輻射Pd/C催化合成α-苯乙胺 5.2，5-二甲氧基苯乙胺鹽酸鹽合成新工藝 展開

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求知網(wǎng)文獻(xiàn)，wangshaobo97@126.com
1.α-苯乙胺的微波合成研究2.以苯乙胺為母體的亞胺配合物的合成及結(jié)構(gòu)3.手性物α-苯乙胺的制備和分析研究4.超聲輻射Pd/C催化合成α-苯乙胺5.2，5-二甲氧基苯乙胺鹽酸鹽合成新工藝... 1.α-苯乙胺的微波合成研究 2.以苯乙胺為母體的亞胺配合物的合成及結(jié)構(gòu) 3.手性物α-苯乙胺的制備和分析研究 4.超聲輻射Pd/C催化合成α-苯乙胺 5.2，5-二甲氧基苯乙胺鹽酸鹽合成新工藝 展開
2012-07-21 08:11:42 332 4
急急急！求知LG 阻燃ABS 320C 320B
聽說Z近ABS市場(chǎng)上揚(yáng)很多？有哪位知道LGABS320C320B的市場(chǎng)信息的朋友，謝謝您的相告！... 聽說Z近ABS市場(chǎng)上揚(yáng)很多？有哪位知道LG ABS 320C 320B的市場(chǎng)信息的朋友，謝謝您的相告！ 展開
2012-05-20 08:11:28 281 2
電表互感器上的電流表串并接法求知（圖）
下面兩圖互感器上的電流表分別串接和并接，兩者用法與看法有什么不同？我一直想不明白并接電流表這圖，電流表都是串聯(lián)呀？
2017-12-14 17:21:48 720 1
2018，目前Z新型的家電有哪些品牌，求知
目前網(wǎng)上，賣場(chǎng)形形的家電，應(yīng)有盡有，進(jìn)賣場(chǎng)不知選什么品牌，求專業(yè)人士回復(fù)，不懂，槍收勿回。... 目前網(wǎng)上，賣場(chǎng)形形的家電，應(yīng)有盡有，進(jìn)賣場(chǎng)不知選什么品牌，求專業(yè)人士回復(fù)，不懂，槍收勿回。 展開
2018-11-24 14:42:43 443 0
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 5
金屬切削刀具 文獻(xiàn)
希望大家能提供點(diǎn)關(guān)于切削刀具的文獻(xiàn) 關(guān)于刀具壽命 刀具磨損啊什么的 只要和刀具有關(guān)的專業(yè)文獻(xiàn)都可以 pdf doc等等格式的都行 寫畢業(yè)論文用的，務(wù)必專業(yè)點(diǎn)的，謝謝啦。有現(xiàn)成文章的可以發(fā)我郵箱 yiluodeyishi@sina.com 也可以給網(wǎng)址，要免費(fèi)的，呵呵 ... 希望大家能提供點(diǎn)關(guān)于切削刀具的文獻(xiàn) 關(guān)于刀具壽命 刀具磨損啊什么的 只要和刀具有關(guān)的專業(yè)文獻(xiàn)都可以 pdf doc等等格式的都行 寫畢業(yè)論文用的，務(wù)必專業(yè)點(diǎn)的，謝謝啦。有現(xiàn)成文章的可以發(fā)我郵箱 yiluodeyishi@sina.com 也可以給網(wǎng)址，要免費(fèi)的，呵呵 先謝謝各位了，注意一定要專業(yè)啊，要求有點(diǎn)高，哈哈 展開
2009-03-04 14:29:07 436 1
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 12:42:12 450 6
電子文獻(xiàn)和印刷型文獻(xiàn)相比有哪些特點(diǎn)
　
2018-11-21 01:07:48 466 0
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 6
渦輪流量計(jì)的文獻(xiàn)圖書
　
2018-11-25 12:10:54 361 0
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 15:14:51 571 1
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 4
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 04:20:15 525 4
平網(wǎng)印花的網(wǎng)框制作
　
2018-11-19 21:51:35 311 0
文獻(xiàn)管理軟件哪個(gè)好用一點(diǎn)？
我在網(wǎng)上看到有人用endnote，有人用noteexpress，還有說notefirst也不錯(cuò)，因?yàn)閯倓偨佑|，想得到一個(gè)比較客觀的評(píng)價(jià)來選擇~
2010-12-07 02:42:18 421 4
接頭linker是什么化學(xué)文獻(xiàn)
　
2017-04-12 20:07:58 332 1
幫忙查一下這篇文獻(xiàn)
文獻(xiàn)名稱Nano Si Cluster- SiOx‐C Composite Material as High-Capacity Anode Material for Rechargeable Lithium Batteries 下載地址：http://jes.ecsdl.org/content/153/2/A425.short 發(fā)郵箱gchui1985@163.com
2012-12-13 10:13:45 430 1

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