稀土元素对固体渗硼层的改性作用

通过研究渗硼层厚度、脆性、表面含硼量、表面形貌的变化及耐锌液腐蚀的性能，充分证实了稀土元素对改善渗硼组织有明显作用。结果表明，改性渗硼组织的耐锌腐蚀寿命大幅度提高，将其制成测温热电偶用于工业生产，耐锌液腐蚀寿命达半年之久，为解决热镀锌设备的腐蚀问题提供了一种有效方法。     

硼钛复合交联剂的合成及交联瓜尔胶研究

以钛酸四异丙酯、乳酸、甘油、三乙醇胺、硼酸、氢氧化钠为原料,合成了硼钛复合交联剂,表征了交联剂结构,制备了瓜尔胶压裂液,考察了中性条件下硼钛复合交联剂与压裂液形成冻胶的耐温耐剪切性能以及粘弹性,研究了冻胶的微观结构。室内实验结果表明:从核磁共振波谱推断出了硼钛复合交联剂的结构,通过交联剂粒径分布确定了硼钛复合交联剂的最佳合成工艺,该交联剂与瓜尔胶交联形成的冻胶,既有硼交联的粘弹性,又有钛交联的耐高温耐剪切性能,可在中性条件下实现有效的交联,为压裂返排液的再利用提供了有效的技术支撑。     

甲亚胺与姜黄素测定土壤有效硼方法的对比研究

土壤有效硼是决定土壤供硼能力的重要指标，目前中国多以沸水浸提土壤，并用姜黄素比色测硼值作为作物硼营养丰缺诊断指标．但在长期实践中，发现作物硼营养状况与热水溶性硼的相关性不稳定，同时测定值重现性不良。为提高作物硼营养诊断和预测的准确性，本研究通过０．０１ｍｏｌ／ＬＣａＣｌ２在２６０℃、３５ｍｉｎ浸提土壤条件下，用甲亚胺比色与沸水浸提，姜黄素比色法测定土壤有效硼的对比研究，证明甲亚胺法测定结果稳定，操作方法简便，适用于低硼土壤的大批量试样的自动分析。为甲亚胺测硼方法的推广应用，本研究已研制甲亚胺粉状试剂获得成功，与进口甲亚胺比较，性能完全一致。     

有孔虫中硼的分离及其正热电离质谱法测定

针对大洋钻探计划(0DP)钻孔中有孔虫数量少、硼含量低的特点，改进了硼特效树脂和阴、阳混合离子交换树脂相结合进行分离硼的方法，成功地实现了硼的分离，并且首次采用正热电离质语法测定了有孔虫中硼同位素的比值。由于硼的分离过程不产生同位素分馏，测定结果令人满意。     

四元硼氮环成键的研究

在４－３１Ｇ基组水平上，对四元硼氮环做了ＳＣＦ－ＭＯ从头算．根据计算结果，由原子的轨道集居以及σ和π电子的分布，讨论了硼原子与氮原子间的成键情况．结果表明，硼有形成多中心σ键的倾向，且环上π电子极化是指向硼的，同时，硼和氮原子上加氢有利于环的稳定．     

硼与人体健康及运动关系的研究进展

近年来的研究表明，硼为人体必需的微量元素。硼不仅影响糖、蛋白质、脂肪三大能量物质的代谢，而且有类雌激素的作用，硼影响钙、镁、磷三种元素的代谢显示出硼具有增加骨密度，预防骨丢失的作用，对于绝经后的妇女预防骨质疏松表现尤为明显。硼的上述作用预示着硼可能为运动员增加力量，提高运动能力有效的运动补剂。运动员摄人充足的硼对保持充沛的运动能力及预防肌肉损伤有积极意义。     

硼纳米结构的理论和实验研究

硼元素,作为第三主族中唯一非金属元素,其原子具有特殊的缺电子性质,因而产生了复杂的键合机制。从硼原子之间的双中心-双电子键到平衡体系电子分布的多中心双电子键,硼因此具有多种同素异形体。低维硼纳米结构材料具有不同于体相的独特结构及特殊性质,相关理论和实验研究已成为近年来的研究热点。本文从理论和实验两个方面,系统介绍了零维硼团簇到一维硼纳米管、硼纳米线及二维硼纳米结构的相关研究,主要针对其结构、性质与潜在应用进行综述。目前,仍需系统化探索其制备及稳定等相关问题,力求揭示其固有属性,以发挥硼基纳米结构材料在未来纳米器件和能源催化方面的重要应用。     

高温结构陶瓷

高温结构陶瓷是一类具有卓越高温性能的无机非金属材料,主要由硅、碳、氧、氮、硼等元素及金属以共价键和离子键结合的化合物构成。其共同特点是,在高温下的强度和硬度高,蠕变小,能抵抗氧和其他化学物质的侵蚀,并有较高的断裂韧性和耐磨损性,其耐机械振动和温度激变的能力也远较一般陶瓷优越。目前国际上     

TiB2/均相硼掺杂TiO2核/壳结构提升光催化氧化水产氧活性

光催化可实现污染物降解、分解水制氢和CO2还原等多种氧化还原反应, 因而受到了广泛关注. 光催化材料中光生电荷的数目与氧化还原能力直接影响光催化反应效率, 在许多光催化反应中, 光生空穴氧化反应被认为速控步骤. 以光催化分解水为例, 质子的还原是单电子过程, 水氧化产生氧气则涉及四个电子. 空穴的高能量不仅可赋予其高的氧化能力,还能提高其迁出表面的能力, 因此具有重要研究价值.我们组的前期工作表明, 以TiB2作为前驱体, 采用水热合成和焙烧两步法可制备出间隙硼掺杂的金红石相或锐钛矿相TiO2, 间隙硼掺杂可显著降低价带顶, 提升光催化氧化水产氧性能. 然而, 在已有的结果中, 间隙硼掺杂浓度在TiO2中均呈现从内向外逐渐增加的梯度分布, 这意味着硼掺杂浓度有限, 且表层更低的价带顶不利于体相光生空穴向表面迁移, 因此亟需实现TiO2中均相的间隙硼掺杂.本文以湿化的氩气为水解环境, 将水解过程限域在TiB2的表面以减少硼原子流失; 同时提高水解温度, 使残留的硼原子形成间隙掺杂, 避免其在二次焙烧时扩散, 从而在TiB2核的表面所形成的TiO2壳层中实现均相间隙硼掺杂, 显著提高了光催化氧化水产氧活性. 多种表征结果表明, 直径约为6-10 μm的TiB2核表面形成了厚约400 nm的TiO2壳层, 在TiO2/TiB2中TiO2壳层重量比约为30%, TiO2壳层中锐钛矿相TiO2占比为65 wt%, 金红石相TiO2占比为35 wt%. TiO2壳层中间隙硼为均相分布, 硼掺杂显著降低了价带顶位置, 提高了光生空穴的氧化能力, 从而使得TiB2/TiO2展现出比未掺杂的金红石、锐钛矿相及两者混合相的TiO2均具有更高的光催化氧化水产氧的能力.     

TiB_2/均相硼掺杂TiO_2核/壳结构提升光催化氧化水产氧活性（英文）

光催化可实现污染物降解、分解水制氢和CO_2还原等多种氧化还原反应,因而受到了广泛关注.光催化材料中光生电荷的数目与氧化还原能力直接影响光催化反应效率,在许多光催化反应中,光生空穴氧化反应被认为速控步骤.以光催化分解水为例,质子的还原是单电子过程,水氧化产生氧气则涉及四个电子.空穴的高能量不仅可赋予其高的氧化能力,还能提高其迁出表面的能力,因此具有重要研究价值.我们组的前期工作表明,以TiB_2作为前驱体,采用水热合成和焙烧两步法可制备出间隙硼掺杂的金红石相或锐钛矿相TiO_2,间隙硼掺杂可显著降低价带顶,提升光催化氧化水产氧性能.然而,在已有的结果中,间隙硼掺杂浓度在TiO_2中均呈现从内向外逐渐增加的梯度分布,这意味着硼掺杂浓度有限,且表层更低的价带顶不利于体相光生空穴向表面迁移,因此亟需实现TiO_2中均相的间隙硼掺杂.本文以湿化的氩气为水解环境,将水解过程限域在TiB_2的表面以减少硼原子流失;同时提高水解温度,使残留的硼原子形成间隙掺杂,避免其在二次焙烧时扩散,从而在TiB_2核的表面所形成的TiO_2壳层中实现均相间隙硼掺杂,显著提高了光催化氧化水产氧活性.多种表征结果表明,直径约为6–10μm的TiB_2核表面形成了厚约400 nm的TiO_2壳层,在TiO_2/TiB_2中TiO_2壳层重量比约为30%,TiO_2壳层中锐钛矿相TiO_2占比为65 wt%,金红石相TiO_2占比为35 wt%.TiO_2壳层中间隙硼为均相分布,硼掺杂显著降低了价带顶位置,提高了光生空穴的氧化能力,从而使得TiB_2/TiO_2展现出比未掺杂的金红石、锐钛矿相及两者混合相的TiO_2均具有更高的光催化氧化水产氧的能力.     

烟草中不同部位尼古丁含量的测定与比较

利用示波极谱法直接测定了贵州、云南、河南和四川四个烟草盛产地所产烟草的烟叶和烟茎中不同部位的尼古丁含量,并对测定结果进行了比较。结果显示:各地烟草上部烟叶尼古丁含量最高,中部次之,下部尼古丁含量最低;尼古丁在茎部的分布以中部最高,下部次之,上部最少。烟叶中的尼古丁含量又远高于其相应的茎。     

Revealing the Unusual Rigid Boron Chain Substructure in Hard and Superconductive Tantalum Monoboride

Poor electrical conductivity severely limits the diverse applications of high hardness materials in situations where electrical conductivities are highly desired. A “covalent metal” TaB with metallic electrical conductivity and high hardness has been fabricated by a high pressure and high temperature method. The bulk modulus, 302.0(4.9) GPa, and Vickers hardness, 21.3 GPa, approaches and even exceeds that of traditional insulating hard materials. Meanwhile, temperature-dependent electrical resistivity measurements show that TaB possesses metallic conductivity that rivals some widely-used conductors, and it will transform into a superconductor at T_c=7.8 K. Contrary to common understanding, the hardness of TaB is higher than that of TaB₂, which indicates that low boron concentration borides could be mechanically better than the higher boron concentration counterparts. Compression behavior and first principles calculations denote that the high hardness is associated with the ultra-rigid covalent boron chain substructure. The hardness of TaB with different topologies of boron substructure shows that besides incorporating higher boron content, manipulating light element backbone configurations is also critical for higher hardness amongst transition metal borides with identical boron content.     

Prepared Low Stress Cubic Boron Nitride Film by Physical Vapor Deposition

We present low stress cubic boron nitride (cBN) films with a transition layer deposited on the metal alloy substrates by tuned substrate radio-frequency magnetron sputtering. The films were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy (TEM). The IR peak position of cubic boron nitride at 1006.3 cm⁻¹, which is close to the stressless state, indicates that the film has very low internal stress. The TEM image shows that pure CBN phase exists on the surface of the film. Several phases of boron nitride were found at the medium implantation dose. It is believed that the transition from the low ordered phases to cBN phase occurred during implantation.     

Characterization of the distribution of the sintering activator boron in powder metallurgical steels with SIMS

Powder metallurgy is a well-established method for manufacturing ferrous precision parts. A very important step is sintering, which can be strongly enhanced by the formation of a liquid phase during the sintering process. Boron activates this process by forming such a liquid phase at about 1200 °C. In this work, the sintering of Fe–B was performed under the protective atmospheres of hydrogen, argon or nitrogen. Using different grain sizes of the added ferroboron leads to different formations of pores and to the formation of secondary pores. The effect of boron was investigated by means of Secondary Ion Mass Spectrometry (SIMS) supported by Scanning Electron Microscopy (SEM) and Light Microscopy (LM). To verify the influence of the process parameters on the mechanical properties, the microstructure (pore shape) was examined and impact energy measurements were performed.The concentrations of B in different samples were varied from 0.03–0.6 weight percent (wt%). Higher boron concentrations are detectable by EPMA, whereas the distributions of boron in the samples with interesting overall concentration in the low wt% range are only detectable by means of SIMS.This work shows that the distribution of boron strongly depends on its concentration and the sintering atmosphere used. At low concentration (up to 0.1 wt%) there are boride precipitations; at higher concentration there is a eutectic iron–boron grain boundary network. There is a decrease of the impact energy observed that correlates with the amount of eutectic phase.     

Effect of mastication time on the low strain properties of short pineapple leaf fiber reinforced natural rubber composites

Pineapple leaf fiber (PALF), used as a reinforcing agent, does not have good adhesion to natural rubber (NR) due to the difference in their polarities. As a result, the degree of reinforcement of NR imparted by PALF remains low compared to that in a polar rubber like acrylonitrile butadiene (NBR). One of the factors that determines the adhesion between the rubber and the reinforcement is the rubber molecular weight. Thus, the aim of this paper is to demonstrate that the stress at very low strains of short pineapple leaf fiber (PALF) reinforced natural rubber (NR) can be significantly increased by lowering the matrix molecular weight. This can be achieved by increasing the matrix mastication time. The composites studied here contain a fixed amount of PALF at 10 part (by weight) per hundred rubber (phr). The PALF fibers were both untreated (UPALF) and sodium hydroxide treated (TPALF). Mastication times of 2, 4, 8 and 16 min were used. Stress-strain curves of PALF reinforced NR prepared with different mastication times were then compared. The most affected region of the curve is in the low strain region. The slopes of the stress-strain curves (moduli) increase with increasing mastication time, indicating better fiber-rubber interaction. The maximum stress achieved at 10% strain is almost 370% that obtained with the usual short mastication time (2 min). The effect remains up to very high strains, although becoming smaller as the strain is increased. Hence, we demonstrate that, by using long enough mastication time, stress-strain curves and stress at low strain of PALF reinforced NR can be improved without the need of any other adhesion promoters.     

氮化硼诱导聚乙烯分子结晶的分子动力学模拟

采用分子动力学方法(MD)研究熔体条件下聚乙烯分子在氮化硼纳米管表面和氮化硼片层表面的结晶机理。通过对聚乙烯分子结晶过程中晶体构象的演变、空间内分子分布的变化以及分子扩散特性的研究,从微观角度比较了两种结构氮化硼纳米材料对聚乙烯结晶的影响。结果表明一维结构的氮化硼纳米管诱导聚乙烯结晶的能力远高于二维片层状的氮化硼,说明纳米材料的维度影响着高分子材料的结晶性能。     

Determination of boron isotopic variations in aquatic systems with negative thermal ionization mass spectrometry as a tracer for anthropogenic influences

A technique for precise boron isotope ratio measurements with a high detection power has been developed by negative thermal ionization mass spectrometry (NTIMS). Relative standard deviations in the range of 0.03-0.3% have been obtained for the determination of the (11)B/(10)B isotope ratio using nanogram amounts of boron. Ba(OH)(2) has been applied as ionization promoter for the formation of negative thermal ions. By adding MgCl(2) better reproducibilities of the measurement have been achieved. A possible interference of BO(-)(2) ions at mass number 42 by CNO(-) could be excluded by the sample preparation technique used. Contrary to other NTI techniques no dependence of the measured isotope ratio on the boron amount used has been observed. Anthropogenic and natural saline influences in ground water have been successfully identified by boron isotope ratio determinations with this NTIMS method, due to the different isotopic composition of boron in natural and anthropogenic substances. In sewage, the boron isotope ratio is substantially influenced by washing powder, which contains low (11)B/(10)B ratios (expressed in delta(11)B values normalized to the standard reference material NIST SRM 951). In contaminated ground water, low delta(11)B values are normally correlated with high boron and high chloride concentrations. On the other hand, delta(11)B shifts to higher values in less contaminated samples. For ground water with saline influences, only the delta(11)B determination, and not the boron or chloride content, allowed the correct identification of this natural source of contamination.     

超细非晶态NiWB合金的制备及葡萄糖加氢性能的研究

通过改变溶液中的Na~2WO~4浓度以化学还原法制备了一系列超细非晶态NiWB合金,并用于葡萄糖高压液相加氢制取山梨醇。研究表明NiWB合金的催化活性均远高于RaneyNi。同时XPS揭示了钨的加入可以调变元素态硼的给电子能力,进而影响硼对羰基的活化和镍对氢的解离吸附能力。在活性最佳的NiWB-3合金上的基本动力学研究表明,葡萄糖加氢反应对氢压为一级,对葡萄糖浓度为零级,在373～403K范围内的反应活化能为54.7kJ·mol^-^1。     

Stabilization of boron clusters with classical fullerene structures by combined doping effect: a quantum chemical study

A combined approach (endohedral doping and exohedral environment) to stabilization of boron clusters with classical fullerene structures has been studied. The boron clusters with classical fullerene structures are stable when heteroatomic part of the complex (endohedral atom and exohedral environment) donates in total 18 electrons to the composite system, stability of which depends on the coordination capabilities and donor ability of the endohedral and surrounding atoms. The most effective stabilization is achieved in the case of the endohedral transition metals atoms, whereas the most effective environment is given by the lithium surrounding.

     

Distribution of aluminum and boron in the periodical building units of boron-containing Beta zeolites

Various boron only ([B]-BEA) as well as aluminum- and boron-containing beta zeolites ([Al,B]-BEA) have been prepared and modified by ion exchange of ammonium, sodium, and nickel ions. The zeolite samples have been characterized by 11B, 27Al, and 29Si MAS as well as three of them by 11B and 27Al 3Q-MAS NMR spectroscopy. The quantitative contributions of defect-free Si(nX) (n = 2, 1, 0; X = Al, B) and Si(OH)x (x = 2, 1) sites to the NMR signal intensities were calculated from the various Si/(Al + B) ratios and relative 11B, 27Al, and 29Si NMR signal intensities using the special distribution of aluminum and boron in different periodical building units of the zeolite framework. The boron atoms are sitting exclusively in diagonal positions in the four-membered rings of [B]-BEA zeolites, while the aluminum atoms are situated both in diagonal and lone positions in the four-membered rings of [Al,B]-BEA zeolites. A higher part of boron atoms are positioned in framework-related deformed tetrahedral boron species than in lattice positions in the [B]-BEA than in the [Al,B]-BEA zeolites. All extraframework octahedral aluminum species are transformed back to lattice positions due to ion exchange from the protonated form to ammonium-, sodium-, or nickel-ions containing zeolites. Oppositely, trigonal boron leaves the zeolite structure completely during ion exchange.