STEREOSTRUCTURE OF POLY［4－（2－METHYLPROPENOYLOXY）－4＇－CYANOBIPHENYL］ BY PHOTOPOLYMERIZATION UNDER AN EXTERNAL ELECTRIC FIELD

ＳＴＥＲＥＯＳＴＲＵＣＴＵＲＥＯＦＰＯＬＹ［４－（２－ＭＥＴＨＹＬＰＲＯＰＥＮＯＹＬＯＸＹ）－４＇－ＣＹＡＮＯＢＩＰＨＥＮＹＬ］ＢＹＰＨＯＴＯＰＯＬＹＭＥＲＩＺＡＴＩＯＮＵＮＤＥＲＡＮＥＸＴＥＲＮＡＬＥＬＥＣＴＲＩＣＦＩＥＬＤ￥ＣｈｏｎｇＷｕＬＩ；Ａ...     

THE APPLICATION OF THE MPB4 THEORY TO THE INTERFACE BETWEEN TWO IMMISCIBLE ELECTROLYTE SOLUTIONS． PART4． THE DIFFERENTIAL CAPACITANCE OF THE WATER／NITROBENZENE INTERFACE IN THE PRESENCE OF 2：2 ELECTROLYTE

ＴＨＥＡＰＰＬＩＣＡＴＩＯＮＯＦＴＨＥＭＰＢ４ＴＨＥＯＲＹＴＯＴＨＥＩＮＴＥＲＦＡＣＥＢＥＴＷＥＥＮＴＷＯＩＭＭＩＳＣＩＢＬＥＥＬＥＣＴＲＯＬＹＴＥＳＯＬＵＴＩＯＮＳ．ＰＡＲＴ４．ＴＨＥＤＩＦＦＥＲＥＮＴＩＡＬＣＡＰＡＣＩＴＡＮＣＥＯＦＴＨＥＷＡＴＥ...     

SYNTHESIS AND PROPERTIES OF THERMOTROPIC LIQUID CRYSTALLINE COPOLYESTERS CONTAINING BIS（4－HYDROXYPHENYL）METHANONE（Ⅵ）

ＳＹＮＴＨＥＳＩＳＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＴＨＥＲＭＯＴＲＯＰＩＣＬＩＱＵＩＤＣＲＹＳＴＡＬＬＩＮＥＣＯＰＯＬＹＥＳＴＥＲＳＣＯＮＴＡＩＮＩＮＧＢＩＳ（４－ＨＹＤＲＯＸＹＰＨＥＮＹＬ）ＭＥＴＨＡＮＯＮＥ（Ⅵ）ＳＹＮＴＨＥＳＩＳＡＮＤＰＲＯＰＥＲ...     

水合希土硝酸盐与本并及单环己基-12-冠-4配合物的合成、性质及晶体结构

在乙腈介质中合成了苯并－１２－冠－４（简称Ｂ－１２－Ｃ－４）和单环己基－１２－冠－４（简称Ｃｙ－１２－Ｃ－４）的六种希土配合物：ＲＥ（ＮＯ３）３·Ｂ－１２－Ｃ－４（ＲＥ＝Ｐｒ，Ｇｄ，Ｙｂ，Ｌｕ），ＲＥ（ＮＯ３）３·Ｃｙ－１２－Ｃ－４（ＲＥ＝Ｌａ，Ｌｕ）。研究了它们的ＩＲ及＾１ＨＮＭＲ性质，并测定了四种单晶的结构，用ＩＮＤＯ法计算了Ｌｕ（ＮＯ３）３·Ｂ－１２－Ｃ－４，Ｌｕ（ＮＯ３）３·Ｃｙ－１２－Ｃ     

包头矿碳酸钠焙烧反应动力学研究

采用热重－差热、Ｘ射线衍射及化学及分析等方法，对包头矿添加１５％碳酸钠焙烧反应进行了研究。在６２３－７４１Ｋ，稀土氟碳酸盐首先分解为ＲＥＯＦ；在８５３－９２８Ｋ，稀土磷酸盐与碳酸钠反应分解为ＲＥ２Ｏ３，并生成Ｃａ８Ｎｄ２（ＰＯ４）６Ｏ２。     

Cu_4-Co-Fe OXIDE CATALYST FOR CYCLOPROPANATION OF 1,1-DICHLORO-4-METHYL-1,3-PENTADIENE WITH METHYL DIAZOACETATE

Ｃｕ４ＣｏＦｅＯＸＩＤＥＣＡＴＡＬＹＳＴＦＯＲＣＹＣＬＯＰＲＯＰＡＮＡＴＩＯＮＯＦ１，１ＤＩＣＨＬＯＲＯ４ＭＥＴＨＹＬ１，３ＰＥＮＴＡＤＩＥＮＥＷＩＴＨＭＥＴＨＹＬＤＩＡＺＯＡＣＥＴＡＴＥＨｕＸｉｎｑｕａｎ１，ＺｈｅｎｇＺｈｕｏ１，Ｘ...     

氧化铈在非贵金属氧化物催化剂中的作用：Ⅵ.Cu—Fe—Ce—O催化剂的结 …

采用ＸＲＤ,顺磁共振（ＥＳＲ）,Ｍｏｓｓｂａｕｅｒ和或温还原（ＴＰＲ）技术对负截型Ｃｕ－Ｆｅ－Ｏ（Ⅰ）,Ｃｕ－Ｆｅ－Ｃｏ－Ｏ（Ⅱ）催化剂的固相结构及热稳定性进行了研究。结果发现,（Ⅰ）中主要存在Ｆｅ２ＣｕＯ４,ＣｕＯ和颗粒度小于１３ｎｍ的Ｆｅ２Ｏ３相。随着焙烧温度的升高,ＣｕＯ晶相逐渐消失,Ｆｅ２ＣｕＯ４的晶相长大。（Ⅱ）中Ｃｅ的存在,能提高Ｃｕ＾２＋的浓度,抑制ＣｕＯ和Ｆｅ２ＣｕＯ４晶相的生成,     

镧系元素Dawson结构钨钒磷四元杂多配合物的合成,表征以…

合成了通式为Ｋ１５Ｈ３〔Ｃｅ（Ｐ２Ｗ１６ＶＯ６１）２〕．６１Ｈ２Ｏ、Ｋ１５Ｈ４〔Ｌｎ（Ｐ２Ｗ１６ＶＯ６１）２〕．ｘＨ２Ｏ（Ｌｎ＝Ｌａ＾３＋，Ｐｒ＾３＋，Ｎｄ＾３＋，Ｓｍ＾３＋，Ｅｕ＾３＋，Ｇｄ＾３＋，Ｄｙ＾３＋，Ｙｂ＾３＋）的９种镧系元素Ｄａｗｓｏｎ结构的钨钒磷四元杂多配合物，并用ＩＲ、ＵＶ、ＮＭＲ、ＥＳＲ、ＸＲＤ、ＴＧ－ＤＴＡ等对其结构和性质进行子研究。该类配合物具有与Ｋ１６〔Ｃｅ（Ｐ２Ｗ１７Ｏ     

二氧化碳加氢合成甲醇铜基催化剂表面组成的研究

本文分别采用ＸＲＤ、ＥＳＲ、ＸＰＳ和ＸＡＥＳ等技术对于二氧化碳加氢低压合成甲醇用ＣｕＯ，ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－Ａｌ＿２Ｏ＿３，ＣｕＯ－ＺｎＯ－ＺｒＯ＿２催化剂在不同条件下表面Ｃｕ、Ｚｎ、Ａｌ、Ｚｒ的存在价态进行了深入分析。实验发现催化剂在还原前Ｃｕ以Ｃｕ￣２＋存在，在还原后和反应状态下以Ｃｕ￣０存在；Ｚｎ在还原后和反应状态下有部分被还原为Ｚｎ￣（２－δ）（０＜δ＜２），Ｚｒ和Ａｌ仍保持其还原前价态。催化剂的表面化学组成为：Ｃｕ￣０／Ｚｎ（２－δ）￣＋／Ｚｒ￣４＋／Ａｌ￣３＋／Ｏ￣２－。     

SYNTHESIS AND PROPERTIES OF THERMOTROPIC LIQUID CRYSTALLINE COPOLYESTERS CONTAINING BIS（4－HYDROXYPHENYL）METHANONE（Ⅴ）

ＳＹＮＴＨＥＳＩＳＡＮＤＰＲＯＰＥＲＴＩＥＳＯＦＴＨＥＲＭＯＴＲＯＰＩＣＬＩＱＵＩＤＣＲＹＳＴＡＬＬＩＮＥＣＯＰＯＬＹＥＳＴＥＲＳＣＯＮＴＡＩＮＩＮＧＢＩＳ（４－ＨＹＤＲＯＸＹＰＨＥＮＹＬ）ＭＥＴＨＡＮＯＮＥ（Ⅴ）￥ＤｅＷｅｎＤＯＮＧ；ＹｕＳｈａｎＮ...     

Phosphate uptake behavior of layered rare earth hydroxides l-RE(OH)3 (RE = Sm,Gd, Er,and Y) from water

The use of rare earths (REs) provides various advantages for removal and recovery of phosphate from water because they have high affinity to form stable complexes with phosphates even at low concentrations. Very low solubility of rare earth phosphate REPO₄ in water was expected to induce a high phosphate adsorption rate and capacity. In this study, layered rare earth hydroxides, l-RE(OH)₃ (RE = Sm, Gd, Er, and Y), have been employed to remove or recover phosphate from aqueous solution. This layered polymorph of l-RE(OH)₃, which is composed of hydroxocation layers, exhibited a high point of zero charge (pH_pzc > 10) and significantly enhanced adsorptive ability for phosphates over a wide pH range. The isotherm and kinetics of phosphate adsorption on l-RE(OH)₃ were explained dominantly by the Langmuir isotherm model and pseudo-second-order kinetic model, respectively. A strong dependence of isotherm and kinetic parameters on RE demonstrated that the adsorption of phosphate on l-RE(OH)₃ is a chemisorption dominated process involving the replacement of –OH by phosphate ion to be included into the coordination polyhedra of RE. The desorption of phosphate from l-RE(OH)₃ was slow but the desorption efficiency for all RE members was higher than 97% in a 1.0 M NaOH solution after 4 days at room temperature. Considering high capacity and stability as well as no significant interference in recovery of phosphate from waters containing common competing anions, this rare earth adsorbent series is proposed as a promising alternative for efficient and sensitive phosphate recovery from natural and wastewaters.     

Precipitation of Rare Earth Phosphates from H3PO4 Solutions

Abstract

A study of several factors has been carried out in order to determine their influence on rare earth phosphates precipitation from H₃PO₄ solutions obtained after the treatment of the Kola phosphate rock.     

我国现行主要稀土矿分解流程的经济技术指标分析

对我国主要稀土矿分解方式进行了阐述，着重讨论了离子吸附型稀土矿、氟碳铈矿和包头白云鄂博矿的典型前处理方式的经济技术指标，对目前最常用前处理方法的投资、生产单耗、成本进行了统计和分析。离子吸附型稀土矿赋存状态奇特，富含高价值中重稀土，但品位低、分布广，多以离子交换的方式开采，环境保护面临的突出问题是植被恢复和废水达标排放；北方矿以轻稀土为主，价值相对较低，原矿品位高，分布集中，露天开采后多以重、磁、浮选工艺选出精矿，然后用煅烧和酸浸结合的工艺进行冶炼，废水和废气以及废渣是环境保护的主题。这些不同稀土矿前处理工艺的特点、发展历史以生产消耗等情况，既可作为稀土生产的投资参考，也可作为稀土企业挖潜改造、提高生产管理水平和环境保护水平的重要依据。     

Rare earth ions-enhanced gold nanoclusters as fluorescent sensor array for the detection and discrimination of phosphate anions

The discrimination and detection of phosphate anions have attracted extensive attention due to their important roles in various biological processes. Compared with sensors to detect one individual phosphate at a time, sensor arrays are able to discriminate multiple phosphates simultaneously. In this study, we developed a rare earth ions enhanced AuNCs-based sensor array to achieve facile and rapid identification of phosphate anions (PPi, ADP and ATP). The rare earth ions (i. e., Ce³⁺, Gd³⁺, Tm³⁺ and Yb³⁺) can significantly enhance the fluorescence of AuNCs through aggregation-induced emission effect. And the subsequent addition of phosphate anions can recover the fluorescence of the AuNCs-rare earth ions assembly. Thanks to the different numbers of phosphate group and different steric hindrance effects of phosphate anions, the recovery fluorescence of AuNCs-rare earth ions assembly induced by PPi, ADP or ATP are respectively distinct. Thus the sensor array composed of AuNCs and different rare earth ions is able to distinguish those phosphate anions. Finally, the sensor array was successfully demonstrated to identify the phosphates in blind samples.     

Emission properties and applications of nanostructured luminescent oxide nanoparticles

Rare earth doped oxide materials are well known for their numerous applications in light emitting devices. An interesting issue is to study the emission properties of nanoparticles, with the aim to understand the influence of small size and surface effects on the emission processes. These particles could furthermore be used in new applications such as the elaboration of transparent emitting devices or new biological labels. The work presented here concerns highly luminescent rare earth doped yttrium vanadates (YVO₄:Eu) and lanthanum phosphate LaPO₄:Ce,Tb·xH₂O nanoparticles. Simple aqueous colloidal syntheses are used for the elaboration of concentrated colloids based on the progressive decomposition of polymeric precursors at moderate temperature (60–90 °C). Both types of particles exhibit strong emission (quantum yields of 25% and 45% for vanadates and phosphates, respectively), but significantly lower than that for the equivalent bulk materials. The alteration of the emission processes is discussed in terms of surface quenching effects. Improvements are obtained through the elaboration of core/shell nanostructures. Surface derivatization has been achieved through the controlled growth of an organically modified silica shell using a functionalized silane precursor. Two examples are given concerning the applications of those particles. The first one is the elaboration of transparent and highly luminescent thin films, obtained by the dispersion of the functionalized particles in a sol–gel silica matrix. The other one is the use of guanidine functionalized particles as biological labels for the single particle detection of sodium channels in cardiac cells.     

Application of electrokinetic supercharging capillary zone electrophoresis to rare-earth ore samples

Capillary zone electrophoresis (CZE) using electrokinetic injection (EKI) with transient isotachophoresis, which was named “electrokinetic supercharging-CZE ” (EKS-CZE), was applied to model samples of rare-earth ores (xenotime and monazite) and a real sample of monazite ore, the abundance of the components being greatly different among samples. When simple EKI was applied, separation and detection of rare-earth ions with smaller mobilities than the major component became difficult with an increase of the content of the major component. In contrast, when EKS-CZE was applied, the minor components (Er, Tm, Yb) with contents less than 0.025% (rare-earth/total rare-earth) could be analyzed. The analytical results for minor components in monazite ore agreed with those obtained by isotachophoresis–particle-induced X-ray emission (ITP–PIXE) and inductively coupled plasma atomic emission spectrometry (ICP-AES) with errors less than 17%. The sample amount required for analysis was 9 μg which is 200-fold smaller than that used in ITP-PIXE analysis. Analytical sensitivity of EKS-CZE was comparable with that of ICP-AES.     

Radiochemical neutron activation analysis of individual rare earth elements in monazites from different geological environments

Radiochemical neutron activation analysis /RNAA/ has been applied for the determination of individual rare earth elements /REE/, except Tm, in 8 Indian monazites and one each from Malaysia and Thailand. Because of the very low amounts of heavy rare earths /HREE/ compared to light rare earths /LREE/ in monazite, HREE from Ho onwards have been determined only after the separation of the heavy and light rare earth fractions in the irradiated monazite samples. The results indicate significant variations in REE contents from Eu to Lu among different monazite samples. The chondritic normalized REE patterns of all the samples show a prominent negative Eu anomaly with different slopes at the heavy rare earth end. All the individual REE, except Tm, have been reported for the first time in various Indian monazites.     

镧配位催化N-十八烷基马来酰亚胺均聚合

N-取代马来酰亚胺聚合物中的酰亚胺环为平面五元环结构,阻碍了酰亚胺单元绕聚合物主链的旋转,限制了聚合物主链的运动,使聚合物的热性能和化学稳定性得到了很大的提高．近些年来,有关N-取代马来酰亚胺均聚合研究的报道已经有很多,但大多采用自由基聚合方法和负离子聚合方法,采用配位催化聚合方法很少．     

热带海洋生物稀土元素生态化学特征分析研究

于中国南海南沙海域采集了30种鱼类、5种贝类和4种甲壳类热带海洋生物,以HNO3-H2 O2为消解体系,利用微波消解进行前处理,并用电感耦合等离子体质谱测定了生物体中稀土元素( Rare earth elements, REE)的含量,分析了稀土元素的生态化学特征。结果表明,微波消解-ICP-MS方法测定稀土元素,各元素的线性关系良好(r=0.9997~1.0000),检出限可达ng/L,准确度高和精密度较好,相对标准偏差(RSD, n=3)<5.0%,各稀土元素回收率在91.5%~106.7%之间。鱼类、贝类和甲壳类生物样品中稀土总量(∑REE)变化范围分别为5.02~34.8μg/kg,30.4~1481μg/kg和103~863μg/kg,3类生物对各稀土元素的富集平均含量为甲壳类>贝类>鱼类,14种稀土元素在鱼类/贝类/甲壳类内含量存在明显正相关性(r>0.80);生物体内轻稀土元素( La~Eu)含量高于重稀土元素( Gd~Lu)含量,从稀土配分模式看出,鱼类/贝类/甲壳类中REE分布模式基本一致, Gd均出现负异常,轻重稀土元素之间有明显的分馏;生物体中δEu值出现负异常,δEu值与相应海域沉积物中δEu值相近,而δCe值出现正异常;同时研究了稀土元素在生物体中的富集和沉积物沉降过程中相关性等。本研究得出的关于热带海洋鱼类/贝类/甲壳类稀土元素的含量和分配规律,可为研究南海水体环境中稀土元素的含量水平和迁移富集提供基础资料。     

Determination of individual rare earth elements in Vietnamese monazite by radiochemical neutron activation analysis

Radiochemical neutron activation analysis (RNAA) has been applied for determination of rare earth elements (REE) in Vietnamese monazite. The chemical separation procedure used is based on the chromatographic elution of rare earth groups, after the separation of²³³Pa(Th) in irradiated monazite samples by coprecipitation with MnO₂, the rare earth elements were retained by Biorad AG1×8 resin column in 10% 15.4M HNO₃-90% methanol solution. The elution of heavy rare earth (HREE) and middle rare earth (MREE) groups was carried out with 10% 1M HNO₃-90% methanol and 10% 0.05M HNO₃-90% methanol solution, respectively; while the light rare earths (LREE) were eluted from the column by 0.1M HNO₃ solution. The accuracy of the method was checked by the analysis of granodiorite GSP-I and the rare earth values were in good agreement.