High temperature thermodynamics of the Cr-Cr2N-N2 system

The high-temperature thermodynamic behavior of the Cr-Cr₂N-N₂ system has been investigated in the temperature range 1450 to 1850 K by measuring the equilibrium pressure of nitrogen gas over pure chromium metal and chromium nitride Cr₂N. From the experimental data, the standard free energy and enthalpy of formation of Cr₂N have been determined to be: ΔH° = −104. ± 10 (KJ. mol⁻¹ Cr₂N) ΔG° = −104. + 0.04987 ± 3.8 (KJ. mol⁻¹ Cr₂N)     

高温稀土永磁Sm2(Co,Cu,Fe,Zr)17 的制备和性能

制备了高温稀土永磁材料Sm(Coba1Fe0．26Cu0．05Zr0．026)7．0，研究了磁性能与工艺条件的关系．结果表明：提高烧结温度可使材料的Br和(BH)max增大，但是使Hci降低；适当提高真空预烧温度，可使材料在较低烧结温度下致密化，具有较高的Hci和(BH)max和温度稳定性．真空预烧温度过高使性能的急剧降低，其主要原因是Sm的析出．在最佳工艺条件下材料的磁性能参数分别为：Br1．08T3Hci2286kA／m，Hcb932kA／m，(BH)max220．8kJ／m^3；β20-200℃为-0．19％／℃．     

Nickel-Carnosine complex:A new carrier for enzymes immobilization by affinity adsorption

Immobilization is an effective method to promote the application of enzyme industry for improving the stability and realizing recovery of enzyme.To some extent,the performance of immobilized enzyme depends on the choice of carrier material.Therefore,the development of new carrier materials has been one of the key issues concerned by enzyme immobilization researchers.In this work,a novel organic-inorganic hybrid material,nickel-carnosine complex (NiCar),was synthesized for the first time by solvothermal method.The obtained NiCar exhibits spherical morphology,hierarchical porosity and abun-dant unsaturated coordination nickel ions,which provide excellent anchoring sites for the immobiliza-tion of proteins.His-tagged organophosphate-degrading enzyme (OpdA) and ω-transaminase (ω-TA)were used as model enzymes to evaluate the performance of NiCar as a carrier.By a simple adsorption process,the enzyme molecules can be fixed on the particles of NiCar,and the stability and reusability are significantly improved.The analysis of protein adsorption on NiCar verified that the affinity adsorp-tion between the imidazole functional group on the protein and the unsaturated coordination nickel ions on NiCar was the main force in the immobilization process,which provided an idea way for the develop-ment of new enzyme immobilization carriers.     

Consolidation and microstructures of microwave sintered W-25Cu alloys with Fe addition

W-25Cu alloys were microwave sintered in a 2.45 GHz multimode applicator. The densification, microstructure and their dependence on sintering mode and Fe addition were investigated in detail. Owing to the volumetric heating intrinsic in microwave processing, a microstructure with larger W grain size in center regions was observed as against larger grain size in edge regions for conventional sintering. Microwave sintering demonstrates its intrinsic advantages such as rapid heating rate, densification enhancement and microstructural homogeneity; but it undesirably promotes W grain growth. Under microwave sintering, the role of Fe addition on compact consolidation is not so substantial as under conventional sintering. Moreover Fe degrades the microstructural quality, generating worse uniformity and coarser W grains.     

2012-2017年呼包鄂城市群夜间灯光动态变化特征及其驱动因素分析

针对当前处于大发展变革阶段的新兴城市群时空变化及驱动因素不明的问题,文章基于2012—2017年夜间灯光影像数据,利用数值统计、标准差椭圆和线性回归等分析方法,结合高分遥感数据和其他辅助数据,研究了呼包鄂城市群夜间灯光在地理空间上的规模分布和变化,分析了夜间灯光的灯光变化与经济发展的关系,并进一步探究了城市群夜间灯光发展的扩张强度、方向以及主要驱动因素。研究结果表明:过去6年间,呼包鄂城市群夜间灯光强度呈现“V”型曲线,与其GDP的发展趋势是一致的;通过椭圆重心分析,显示整个城市群的夜间灯光重心向位于西南方向的鄂尔多斯市移动,鄂尔多斯市对整个城市群的经济发展有较强的拉动作用;利用夜间灯光驱动因子分析,并结合高分遥感光学影像以及灯光变化的区域,发现呼包鄂城市群的发展受能源因素的影响最大,是目前主导城市群发展的关键因素。     

利用T-PROGS确定最优钻孔密度

为了在水文地质钻探时找到合理的钻孔密度,避免钻孔集中出现数据的冗余,造成介质类别有偏向于高密度钻孔岩性类别的趋势。本文以某实测区域为研究对象,运用GMS软件中T-PROGS模块,模拟在非均匀介质中均匀分布钻孔以确定最优钻孔密度。通过马尔可夫数学预测模型对计算机模拟数据进行甄选,得出在钻孔密度为30孔/km2,获得的水文地质资料的可信度较高,可以最大限度的节省人力物力。本文研究结果表明:结合GMS软件与马尔科夫预测模型对探明地质类型分布是可行的。     

铑与DBS—偶氮氯膦的新显色反应

研究了Rh与DBS—偶氮氯膦的显色反应。在Na_2HPO_4—H_3PO_4缓冲介质中,当抗坏血酸存在并加热的条件下可生成蓝色配合物。Rh含量在0～22μg/25ml符合比尔定律,ε_(620)=1.25×10~4。此方法用于Rh—Ir回收液中Rh的测定,结果满意。     

金、银、铂、钯合金中钯的选择性滴定方法的研究与应用

建立了丁二肟选择性沉淀分离和析出EDTA-Pd络合物中的EDTA,Pb(NO3)2返滴定测定Pd的新方法,系统地研究了在硝酸或盐酸介质中测定Pd的条件,并对比了本法与《国家标准》分析方法的结果.研究表明:2种方法测得Pd的结果吻合,测定5～30mg Pd,相对误差-0.17% ～ 0.20%;但拟定方法的选择性好,适用性强,分析快速,操作简便、易于掌握.方法已应用于Au、Ag、Pt、Pd合金中5%～99%的Pd含量的测定,结果满意.     

台式快速成型设备扫描系统研制

介绍了在台式快速成型制造系统研制中，为稳定系统性能、降低设备造价所采取的技术措施：通过对扫描方式的比较，选择了X－Y二维导轨式扫描方式；用普通紫外灯光源取代激光光源；基于锥度光纤传输、聚焦的光路系统等技术。