离散型空间焊道CBN砂带当量随行磨削技术

提出一种离散型空间(椭圆形、马鞍形、相惯线形等)焊道的磨削加工技术——立方氮化硼(Cubic boron nitride,CBN)砂带当量随行磨削方法,该方法一方面基于测量技术以及磨削量预测模型,利用四轴联动以及恒压力浮动砂带磨削技术实现离散型空间焊道当量随形磨削加工,保证焊道的等余量控制;另一方面针对焊道材料的难加工特性,运用CBN砂带实现高效率、高精度磨削加工。阐述了当量随行磨削加工原理,建立随行磨削加工模型,分析随行运动误差。基于测量技术以及磨削量预测模型,建立当量磨削控制方程。针对椭圆形焊道典型零件——燃烧室机匣进行了磨削加工试验,得到其磨削余量厚度误差在±0.005 mm以内,证明该方法的可行性,得到焊道磨削的最优工艺(砂带线速度24 m/s,磨削压力170 N,工件转速1r/min),并且得到工件旋转速度是影响材料去除率最大的工艺参数。     

硼化物、锰去除再生Al-Si合金中铁元素机理研究

研究了KBF4和KBF4、Mn对再生Al-Si合金中的富铁相变质行为的影响以及采用沉降法进行除铁探索。应用光学显微镜(OM)、扫描电镜(SEM)对试样组织进行形貌观察,采用X射线衍射仪分析仪(XRD)、X射线荧光光谱分析仪(XRF)对试样进行相分析和成分分析,利用差分扫描量热仪(DSC)研究相转变温度。研究表明,硼化物(KBF4)能促使再生Al-Si合金析出初生α-Fe相;Mn元素能促使初生α-Fe相长大,初生α-Fe相会沉淀到炉底。加硼化物(KBF4)、Mn的再生Al-Si熔体随炉冷却形成的铝锭,铁含量随着离铝锭顶端的距离增加而增加,铝锭中上部铁含量低于原始量。     

硼元素对Ti-Al-Cr-Fe系合金晶粒尺寸的影响

利用光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)等设备或技术研究了B元素对Ti-Al-Cr-Fe系合金晶粒尺寸的影响,合金状态包含有铸态、锻态和固溶态。结果表明:B元素具有明显细化钛合金晶粒的作用,主要是由于在熔炼凝固过程中产生的Ti B相所致,Ti B相的存在可细化合金铸态组织,并钉扎晶界,阻碍后续热加工过程和热处理过程中原始β晶粒长大,可起到减少变形火次,从而降低加工成本。由于Ti B相的存在,Ti-3Al-3.7Cr-2.0Fe-0.1B合金在铸态、锻态以及热处理态组织中的晶粒均比Ti-3Al-3.7Cr-2.0Fe合金中的要细小;且在相同条件下固溶后Ti-3Al-3.7Cr-2.0Fe-0.1B合金中的晶粒尺寸大小在69~88μm,为Ti-3Al-3.7Cr-2.0Fe合金中晶粒的52.7%~67.0%。     

Physical and mechanical properties of hexagonal boron nitride ceramic fabricated by pressureless sintering without additive

Hexagonal boron nitride hBN ceramic was successfully fabricated by pressureless sintering at 2100C using submicrometre hBN powders without any sintering additive. The as-prepared hBN ceramic showed a room temperature flexural strength of 30.7MPa. Its flexural strength increased with the increment of temperature in N₂ atmosphere, and it retained a strength of 57.2MPa nearly two times of the room temperature strength at 1600C due to clean grain boundaries with no glassy phase. Additionally, the as-prepared hBN ceramic showed a high thermal conductivity of 31.76Wm¹k¹ and a good thermal shock resistance, which retained a relatively high residual flexural strength of 22.6MPa 73.5 of the original flexural strength at T800C. The as-prepared hBN ceramic presents a good application prospect at high temperature.     

Receptor‐Mediated Uptake of Boron‐Rich Neuropeptide Y Analogues for Boron Neutron Capture Therapy

Peptidic ligands selectively targeting distinct G protein‐coupled receptors that are highly expressed in tumor tissue represent a promising approach in drug delivery. Receptor‐preferring analogues of neuropeptide Y (NPY) bind and activate the human Y₁ receptor subtype (hY₁ receptor), which is found in 90 % of breast cancer tissue and in all breast‐cancer‐derived metastases. Herein, novel highly boron‐loaded Y₁‐receptor‐preferring peptide analogues are described as smart shuttle systems for carbaboranes as ¹⁰B‐containing moieties. Various positions in the peptide were screened for their susceptibility to carbaborane modification, and the most promising positions were chosen to create a multi‐carbaborane peptide containing 30 boron atoms per peptide with excellent activation and internalization patterns at the hY₁ receptor. Boron uptake studies by inductively coupled plasma mass spectrometry revealed successful uptake of the multi‐carbaborane peptide into hY₁‐receptor‐expressing cells, exceeding the required amount of 10⁹ boron atoms per cell. This result demonstrates that the NPY/hY receptor system can act as an effective transport system for boron‐containing moieties.     

由西藏天然硼砂矿提取硼砂的工艺研究

文章介绍了通过有机絮凝剂从西藏天然硼砂矿中提取硼砂的工艺途径 ,给出了最佳的工艺条件 ,在该条件下硼砂矿的收得率达到 94 %以上     

硼改性微粒硅溶胶的研制及应用

用硼化物对硅溶胶进行表面改性，最佳的改性方案是将硼化物与硅酸钠混合形成尾料。再将未碱化、末熟化的酸性硅溶胶滴加入尾料中。n（B）：n（Si）=0．08-0．1，硼改性微粒硅溶胶体积分数约为5％。其助留助滤性能优良，与空白样相比可使浆料留着率提高2～3倍，留着率比进口的NP882提高约30％。硼改性制备的硅溶胶霞现性好，性能稳定。     

Boron‐doped selective silicon epitaxy: high efficiency and process simplification in interdigitated back contact cells

The present research and development activities in crystalline silicon photovoltaics include the exploration of doping technologies alternative to the mainstream diffusion process. The goal is to identify those technologies with potential to increase the solar cell efficiency and reduce the cost per watt peak. In that respect, this work presents the selective epitaxial growth of silicon as a candidate for boron doping; showing the results of the evaluation of boron‐doped silicon epitaxial emitters on slurry and diamond‐coated wire‐sliced Czochralski material, their integration in interdigitated back contact solar cells, and the development of a novel process sequence to create the interdigitated rear junction of these devices using selective epitaxial growth. Boron‐doped silicon epitaxy is demonstrated to perform in the high efficiency range (>22%), and the use of selective epitaxial growth is proposed as a route for the simplification of the interdigitated back contact solar cell flow. Copyright © 2013 John Wiley & Sons, Ltd.     

D564树脂分离油田卤水中的硼

用D564树脂分离青海南翼山油田卤水中的硼,考察了卤水pH值、流速对B2O3吸附量的影响以及酸浓度、流速对B2O3洗脱的影响.结果表明:在pH=8,流速为2 mL/min时,B2 O3的吸附率可达99.4％;用1 mol/L H2SO4以2 mL/min的流速洗脱时,B2 O3的解脱率达98.0％;整个过程B2 O3的...     

过冷度对重掺B直拉Si单晶中小角晶界的影响

小角晶界是Si单晶中的严重缺陷,生产中需要极力避免。对于重掺B直拉<111>Si单晶,当掺杂浓度接近固溶度时就容易产生小角晶界。对直拉Si单晶中小角晶界产生的原因进行梳理及深入分析,在理论上提出减少过冷度来减少小角晶界缺陷的方法。分别采用增加加热器功率减小过冷度及降低埚位减少过冷度的两种工艺方法,成功实现生长无小角晶界重掺B<111>Si单晶。通过生产中实际晶体生长情况对比分析发现,低埚位生长无小角晶界的重掺B直拉<111>Si单晶工艺更具备生产优势。