碳化钨粉末注射成形一步热脱脂的脱脂动力学

采用热重分析法测定了在氮气气氛中5℃/min、10℃/min、15℃/min和20℃/min不同升温速率下的石蜡、保形聚合物(PP与HDPE的混合物)、石蜡/保形聚合物和碳化钨(WC-10%Ni)粉末注射成形专用料的热解过程,采用Kissinger法和Flynn-Wall-OZAWA法对4种专用料的热分解动力学进行分析,并用Coats-Redfern研究反应级数。结果表明,用Kissinger法分析不能很好地反映混合物的复杂的热解过程,不能支持碳化钨粉末注射成形一步热脱脂的工艺制定。用Flynn-Wall-OZAWA法分析,石蜡的热分解活化能在59~72 k J/mol,保形聚合物的热分解活化能在143~252 k J/mol,石蜡/保形聚合物的热分解活化能在60~240 k J/mol和WC-10%Ni的专用料的热分解活化能在93~220 k J/mol。用CoatsRedfern法分析,石蜡与保形聚合物的热解可用一级反应来描述,而石蜡/保形聚合物与WC-10%Ni的专用料的热解则适用3个连续一级反应来描述。

Method for evaluation of the cleanliness grade of coal resources in the Huainan Coalfield,Anhui,China:a case study

Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield,a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam(No.13-1)The results showed that:(1)The contents of Cr,Mn and Ni in the coal seam are relatively high and the average values are greater than 20μg/g.The contents of Se and Hg are at a high level while most other trace elements are at normal levels.(2)The cleanliness grade of the coal seam is mainly grade III-IV,which corresponds to a relatively good-medium coal cleanliness grade.However,some parts of the seam are at grade V(relatively poor coal cleanliness).(3)Coal of relatively good cleanliness grade(grade III)is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine.Coal of medium cleanliness(grade IV)is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines.Relatively poor grade coal(grade V)is distributed in the southwest regions of the coalfield and the contents of Cr,As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.

聚丙烯/三聚氰胺泡沫高吸油韧性材料

采用聚丙烯甲苯溶液对三聚氰胺泡沫进行浸渍处理得到改性三聚氰胺泡沫材料。傅里叶变换红外光谱和扫描电子显微镜分析表明,聚丙烯成功包覆在三聚氰胺泡沫骨架表面,形成了微纳级凹凸结构。改性泡沫表现出吸油拒水的特点,水接触角均在130°以上。改性泡沫材料吸收柴油和多种溶剂的量在45～98 g/g之间,重复吸油100次后的吸油能力保持率在93%以上,表明该材料具有高吸油效率及可重复使用性。拉伸测试表明改性泡沫相对于未改性泡沫的韧性得到提高。该方法工艺简单,原料成本低,容易工业化,为高吸油韧性吸附剂的制备以解决油污染问题提供了一种新的途径。

星形含氟嵌段丙烯酸酯聚合物的合成及涂料性能

利用引发剂连续再生原子转移自由基聚合法(ICAR-ATRP)合成一系列结构及组成不同的聚(甲基丙烯酸丁酯-co-甲基丙烯酸缩水甘油酯)-b-聚甲基丙烯酸十二氟庚酯嵌段共聚物,并用于制备涂料。探索了聚合物星形结构和甲基丙烯酸缩水甘油酯(GMA)含量对聚合物性能和漆膜性能的影响。采用核磁共振氢谱,凝胶渗透色谱,差示扫描量热分析仪,接触角等方法对聚合物的结构及性能进行了表征。结果表明,同等化学组成下,星形含氟嵌段聚合物拥有比线型聚合物更低的玻璃化转变温度、黏度和更好的疏水性能。当聚合物GMA结构单元的质量分数为10%时,固化漆膜的水接触角达到112°,采用自制的脂环胺固化剂使得漆膜具有较好的耐紫外老化性能。

Geochemical,mineralogical,and petrological analyses for the interpretation of the sedimentary environment of the Middle-Late Ordovician Majiagou Formation(northern China)as a tool for more effective gas exploration

Core samples from the deeply buried Ordovician Majiagou Formation below the Huainan Coalfield(E China) have been investigated for their carbonate types,major and trace elements(including rare earth elements) and C and O isotopes,The objective was to get a better insight into the possible occurrences of gas(and possibly oil) derived from Carboniferous coals.It was found that the carbonates are dolomites with strongly varying amounts of CaO and MgO.The low concentrations of SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3)indicate deposition in a normal marine environment with little terrigenous input,The Na_(2)O/K_(2)O,Fe/Mn and Sr/Ba ratios,as well as the Ga values indicate mainly a marine salinity and a hot and humid climate.The slight depletion of Ce and Eu,the depletion of heavy rare earth elements(HREE) and the enrichment of light rare earth elements(LREE) indicate deposition in a reducing environment.It thus appears that the Majiagou Formation below the Huainan Coalfield closely resembles that in the eastern part of the Ordos Basin,where several gas reservoirs are present,so that the Majiagou Formation under the Huainan Coalfield represents a promising target for hydrocarbon exploration.

Characteristics and geological significance of germanium in Taiyuan coal formation of Huainan Coalfield,Anhui,China

HN-1#is the first fully working coring well of the Taiyuan Formation(Ty)in the Huinan Coalfield and exploration studies are currently underway on the associated resources of the coal-bearing strata.The HN-1#well is located in the Fufeng thrust nappe structural belt in the south of the Huainan Coalfield.Three coal samples from the Ty were collected from HN-1#and inductively-coupled plasma mass spectrometry and inductively-coupled plasma atomic emission spectrometry were used to determine the Ge content of each sample.Based on proximate and ultimate analyses,microscopy data,and analyses of the ash products,some important findings were made.The Ty coal samples had a relatively high total sulfur(Sud)content(4.24%),thus the coal was considered to be a lower ranked coal(high volatility bituminous coal),which also had a low coal ash composition index(k,1.87).Collodetrinite was the main submaceral of the Ty coal.Small amounts of pyrite particles were found in the coal seams of the Ty,while the contents of pyrite and algae in the top and bottom sections of the coal seam were relatively high,which meant that the swampy peat conditions which existed during the formation of the coal seams were affected by seawater;also the degree of mineralization of the coal seam was relatively high,which is consistent with reducing conditions in a coastal environment setting.Atomic force microscopy(AFM)experiments showed that the modes of occurrence of Ge in the Ty coal were mainly those for organic-bound and adsorbed Ge species.The organic carbon isotope values for the Ty coal ranged from-24.1‰to-23.8‰,with an average value of-24.0‰,which is equivalent to the value for terrestrial plants(average value-24.0‰).The Ge content of the Ty coal was 13.57 mg/kg.The Ge content was negatively correlated with volatile matter and the ash yield.

Structure and Electrical Properties of Oxide Doped Rhombohedral Pb(Ni1/3Nb2/3)O3-PbTiO3 Ferroelectric Ceramics

0.7Pb(Ni1/3Nb2/3)O3-0.3PbTiO3 (0.7PNN-0.3PT) and 1 mol% La2O3-, Y2O3-, ZnO-, MnO2- and Nb2O5-doped 0.7PNN- 0.3PT ferroelectric ceramics were prepared by the conventional solid-state reaction method via the columbite precursor route. The ceramics sintered at 1180℃ exhibit pure rhombohedral perovskite structure except the Y2O3-doped 0.7PNN-0.3PT ceramics. The oxide-doped 0.7PNN-0.3PT ceramics exhibit rather homogeneous microstructure and improved densification, especially for the MnO2-and La2O3-doped 0.7PNN-0.3PT (defect) ceramics whose relative density is larger than 96%. All the above dopants decrease the dielectric loss of the 0.7PNN-0.3PT ceramics, whereas the values of the dielectric maximum (?m) and the temperature of ?m (Tm), and the character of dielectric response vary differently. ZnO and Nb2O5 doping increase remanent polarization Pr, and La2O3, ZnO, MnO2 and Nb2O5 doping decrease coercive field Ec of the 0.7PNN-0.3PT ceramics. Piezoelectric property is greatly improved by Y2O3, MnO2, Nb2O5 and ZnO doping, where the MnO2-doped 0.7PNN-0.3PT ceramics exhibit the largest value of piezoelectric constant d33, which reaches 191 pC/N.

Developing Statistical Modellings to Investigate the Internal Drivers for the Trend of Output Values in the Manufacturing Industry:Evidence from Chinese Enterprises

The manufacturing industry is an important pillar of the national economy.It is of vital importance to develop statistical modellings in order to quantify the relationship between potential internal drivers and the trend of output values in the manufacturing industry.However,only a few statistical modellings have been established to investigate such associations.This study developed the correlation coefficient model and generalized linear model(GLM)to measure the single and interactive effects of the internal drivers on the changes of the output values.For the GLM,different predictive variables were developed to fit into the dataset,and the performance of the models were compared using fitness parameters.Furthermore,an industry survey dataset for 1,180 manufacturing enterprises in 2020 was used to validate the models.The use of the GLM combining land area,number of employees,scientific research input,and labor productivity may have a great potential to bolster capacity in monitoring and predicting the trend of output values in the manufacture industry.

基于非等温法的废弃环氧树脂电路板热解动力学分析

热解技术在处理废弃电路板,回收电路板中的金属,实现树脂、玻璃纤维等非金属成分的资源化方面发挥愈来愈重要的作用,但目前对于不含任何电子元件、含少量铜箔的废弃环氧树脂电路板的热解机理研究尚不明确。为阐述其热解催化作用,采用同步热分析仪和气相色谱-质谱联用(GC-MS)仪对不同升温速率(5,10,15,20℃/min)下电路板的热解特性及热解机理进行分析。结果表明,废弃电路板热解过程主要分为四个阶段:表面残余水蒸发或其他小分子散逸、环氧树脂侧链基团氧化、四溴双酚A的分解和热解残留物分解;运用Kissinger法、Flynn-Wall-Ozawa法及Friedman法等明确单一反应的热解区间并求解热分解反应动力学参数,最终得到指前因子1.14×10^(22)min^(-1)和活化能218.533 kJ/mol;采用Šatava-Šesták法和主曲线法进行机理函数对比分析,最终表明废弃环氧树脂电路板适用随机成核与增长模型:Avrami-Erofeev方程模化。研究结果可为促进热解技术的应用提供理论支撑。