国外某高磷鲕状赤铁矿直接还原—磁选降磷研究

以国外某高磷鲕状赤铁矿为研究对象进行脱磷研究，该高磷矿铁品位为55.81%，磷含量为0.72%，铁矿物主要为磁铁矿和赤铁矿，48.61%的磷存在于磷酸盐中，47.22%的磷分布于铁矿物中。研究了脱磷剂用量、秸秆炭用量、还原温度以及还原时间对粉末还原铁指标的影响。结果表明：无脱磷剂碳酸钙时，无法获得合格的指标；在碳酸钙用量为25%，秸秆炭用量为12.5%，还原温度1 200 ℃，还原时间为75 min，还原产品两段磨矿两段磁选的条件下，可获得铁品位、铁回收率以及磷含量分别为94.27%、87.34%以及0.077%的粉末还原铁，该产品可作为电炉炼钢的优质原料。不加添加剂时，部分含磷矿物被还原成单质磷进入到金属铁中，故粉末还原铁磷含量较高，当碳酸钙用量为25%时，含磷矿物的还原受到抑制而保留在脉石相中，可实现降磷目的，而还原时间过长时，磷仍在脉石相中，铁颗粒将部分含磷矿物包裹，磨矿难以分离，导致磷含量升高。     

强变形工艺对2519A铝合金组织与性能的影响

通过硬度测试、拉伸性能测试、透射电镜观察等分析手段研究了不同强变形工艺下2519A铝合金的力学性能与微观组织。结果表明,经50%的冷轧变形和165 ℃人工时效后,2519A合金的力学性能明显提高,其抗拉强度、屈服强度和伸长率分别为522 MPa、468 MPa和8.5%。而在冷变形前添加165 ℃×2 h预时效处理,合金的力学性能进一步提高,其抗拉强度、屈服强度和伸长率分别达到535 MPa、497 MPa和8%。预时效处理可以提高合金中θ′相的密度,使析出相分布更加均匀,有助于提高合金的力学性能。     

退火工艺对激光选区熔化成形Ti6Al4V合金组织及室温力学性能的影响

以Ti6Al4V球形粉末为原料,利用激光选区熔化成形方法制备了Ti6Al4V合金试样,采用光学显微镜、扫描电镜及力学性能测试等手段,研究了退火工艺对Ti6Al4V合金室温力学性能及组织的影响规律。结果表明: SLM成形沉积态Ti6Al4V合金室温抗拉强度超过1200 MPa,而平均断后伸长率仅为4.0%;在650 ℃下进行真空退火处理,合金的抗拉强度仍保持在1200 MPa左右,规定塑性延伸强度R_p0.2高于1150 MPa,但试样的断后伸长率<10%;而在750及800 ℃下进行真空退火处理,合金试样的抗拉强度降至1100 MPa左右,规定塑性延伸强度高于1050 MPa,伸长率达到甚至超过10%,材料的综合强韧性得到明显提升。随着真空退火加热温度和保温时间的增加,SLM成形Ti6Al4V合金原始β晶界逐渐变模糊,晶粒趋向于等轴化。与此同时,快速冷却转变的α′针状马氏体未出现明显地粗化。     

计及RSC控制的DFIG短路电流直流分量解析表达

现有文献针对计及转子变流器(RSC)控制的双馈感应风电机组(DFIG)定子短路电流解析表达,将定子磁链当作一阶直流衰减分量或忽略功率外环控制。基于DFIG电压、磁链和RSC控制方程,得到定子电流关于定子电压和定子功率的传递函数,提出定子电流的精确解析表达式。基于RSC内、外环PI参数关系,推导直流分量衰减时间常数和角频率关于PI参数的表达式。分析了RSC内外环PI参数对定子电流直流衰减分量的影响。仿真结果验证了解析表达式的准确性,为PI参数选取和保护装置测量、整定提供依据。     

Effect of laver powder on textual,rheological properties and water distribution of squid (Dosidicus gigas) surimi gel

In order to ameliorate the gel quality of Dosidicus gigas surimi, the effects of laver powder on gel properties, rheological properties, and water-holding capacity (WHC) were investigated. Results indicated that the addition of laver powder could significantly increase the hardness, chewiness, and breaking force of surimi gels. However, the texture indexes and gel strength began to decline when additional amount exceeded 0.6%. Rheological results demonstrated that the addition of laver powder increased the storage modulus (G′) and viscosity of surimi, prolonged protein denaturation temperature in surimi gels. Moreover, the WHC of surimi gel was improved with the increase of laver powder. Further analyses in low-field nuclear magnetic resonance revealed that laver powder could shorten the transverse relaxation time, enhanced the combination with water, and altered the distribution of different water categories. The proportion of bound water and immobilized water reached its maximum and minimum at 0.6% of laver powder, respectively. Correlation analyses showed that WHC of surimi gel was negatively correlated well with the proportion of loose-bound water, but positively correlated with the strong-bound water and free water. In conclusion, the results supported that 0.6% was the optimal additional amount of laver powder for the squid-based surimi production based on the current ingredients of surimi products.     

HACCP在浓香菜籽油生产中的应用

为了保障浓香菜籽油的产品质量安全,采用HACCP体系对浓香菜籽油生产全过程进行生物、物理、化学的危害分析,确定关键控制点,制定预防措施,并对生产环节进行有效监控,制定纠偏措施,做好记录管理,为浓香菜籽油的安全生产提供借鉴。     

Advanced Functional Materials Constructed from Pillar[n]arenes

Pillar[n]arenes are new generation of supramolecular macrocyclic host, which exhibit excellent host−guest recognition properties. In the last decade, functional materials constructed from pillar[n]arenes have been attracted more and more attention and displayed outstanding characteristics, such as stimuli-responsiveness, self-healing and adaptability. In this mini-review, we provide a survey of the pillar[n]arene-based literatures covering light-harvesting systems, functional hydrogels, and solid materials. It is anticipated that more and more pillar[n]arenes-based advanced materials with multi-functional properties will appear in the near future.     

应用组合起泡剂优化黑、白钨混合浮选

针对湖南某钨选厂使用杂醇类起泡剂BK205所产生的泡沫小、性脆、泡沫层薄等不利于二次浮选的特点,采用BK205与新型醚类起泡剂CU组合使用以便实现矿石中钨矿物的高效回收。结果表明,在采用BK205与新型醚类起泡剂CU组合质量比为3∶1、先BK205后CU的加药方式下,小型闭路试验得到精矿WO3品位为30.13%,回收率为78.98%。工业试验表明,组合起泡剂不仅改善浮选泡沫,减少药剂用量,降低药剂成本,而且能获得比原起泡剂更好的工业指标,使钨矿物得到更高效的回收。     

A broadband filter with two transmission zeros adopting a new design method

A new design method was proposed in this article to insert transmission zeros in the broadband filters. In this method, the coupling line was connected to a certain position on the resonator. And then the coupling strength was adjusted by the connecting position. The open end of the resonator was hung and then the cross‐coupling was introduced to realize transmission zeros. This coupling method could add an adjustable parameter to improve the freedom of design and convenient to insert the transmission zeros. To verify this method, a highly selective coupled‐line microstrip filter with two transmission zeros was designed, fabricated, and measured. The measured results were in good agreement with the simulated ones. The return and insertion losses of the broadband filter were better than 18 and 2 dB, respectively. The relative bandwidth of the filter (FBW) was more than 68%. The rectangular coefficient (30 dB:1 dB) was less than 1.21.