摆动活齿齿轮传动的中心轮齿形加工原理及方法

根据摆动活齿齿轮传动原理，设计出在Ｙ５４插齿机上展成加工中心轮齿形的加工方法，为普及和推广摆动活齿齿轮传动创造了有利条件．     

水/二氧化碳气氛下酒糟催化气化反应特性的研究

在固定床气化装置中,以赤泥为催化剂、水/二氧化碳为气化剂对酒糟进行气化实验。研究了赤泥添加量、气化温度和V（水）/V（二氧化碳）对酒糟气化活性的影响,并对水/二氧化碳共气化协同机理进行了探讨。结果表明：当赤泥添加量为20%（质量分数）时气化活性最佳;升高气化温度有利于提高气化反应活性;随着V（水）/V（二氧化碳）的增大,合成气产量、n（氢气）/n（一氧化碳）均增加,分别达到270.7 mmol/g和6.67;在水/二氧化碳混合气氛下共气化反应产生了明显的协同效应,协同因子在60%水-40%二氧化碳（体积分数）时达到峰值。拉曼光谱、扫描电子显微镜及比表面积分析表明：水/二氧化碳混合气氛下酒糟焦无定形碳和非晶碳结构的破坏程度比在纯水或二氧化碳中更严重,验证了二氧化碳和水在酒糟气化中存在协同效应;二氧化碳更容易在酒糟焦表面发生气化反应,形成大量微孔使其比表面积增加;水炭渗透力较强有利于形成中孔;在水/二氧化碳混合气氛下,二氧化碳与水产生的交互作用促进了孔结构的发育,使酒糟焦的微孔发展为中孔和大孔并促使气化反应向酒糟颗粒内部发展,这是协同效应产生的主要原因。     

Preparation of Si3N4 ceramic based on digital light processing 3D printing and precursor infiltration and pyrolysis

The emergence of digital light processing (DLP) 3D printing technology creates favorable conditions for the preparation of complex structure silicon nitride (Si₃N₄) ceramics. However, the introduction of photosensitive resin also makes the Si₃N₄ ceramics prepared by 3D printing have low density and poor mechanical properties. In this study, high-density Si₃N₄ ceramics were prepared at low temperatures by combining DLP 3D printing with precursor infiltration and pyrolysis (PIP). The Si₃N₄ photocurable slurry with high solid content and high stability was prepared based on the optimal design of slurry components. Si₃N₄ green parts were successfully printed and formed by setting appropriate printing parameters. The debinding process of printed green parts was further studied, and the results showed that samples without defects and obvious deformation can be obtained by setting the heating rate at .1°C/min. The effect of the PIP cycle on the microstructure and mechanical properties of the Si₃N₄ ceramics was studied. The experimental results showed that the mass change and open porosity of the samples tended to be stable after eight PIP cycles, and the open porosity, density, and bending strength of the Si₃N₄ ceramics were 1.30% (reduced by 97%), 2.64 g/cm³ (increased by 43.5%), and 162.35 MPa.     

中国矿山型锂矿资源分布及提取碳酸锂技术

分析了中国矿山型锂矿资源分布及矿物特征,阐述了中国矿山型锂资源开发技术进展,对中国若干矿山型锂矿资源提取碳酸锂工艺路线进行了分析和比较。并指出,中国以青海盐湖为代表的盐湖卤水提锂由于较高的镁锂比,盐湖提锂一直存在技术瓶颈,目前的技术水平难以实现镁锂分离。基于中国丰富的矿山型锂矿资源状况,从矿山型锂矿提取碳酸锂仍将是中国相当长一段时期内主要的锂资源来源,中国应重视矿山型锂矿资源技术研究,加大研究开发力度,使中国矿山型锂矿资源得到有效和保护性开发。     

双酚AF型聚碳酸酯的制备与性能

以三光气和双酚AF为原料,采用界面缩聚法合成双酚AF型聚碳酸酯,得到最佳的聚合条件为：三光气和双酚AF的物质的量之比为1.3∶3,催化剂三乙胺的用量为双酚AF质量的4%,反应温度为35℃,反应时间为60 min。通过傅里叶变换红外吸收光谱、乌氏黏度计、同步热分析仪、热变形/维卡软化温度测试仪及极限氧指数测定仪对制备样品进行了结构和性能表征,结果表明,制备样品为双酚AF型聚碳酸酯,样品的黏均分子量为32000。玻璃化转变温度为164.3℃,热失重5%的温度为440.8℃,热变形温度为149℃、维卡软化温度为157℃,具有较好的耐热性能;极限氧指数为29.5%,具有较好的阻燃性能。样品经碱溶液浸泡后质量损失率较小,耐碱腐蚀性能较好。样品在很多有机溶剂中都有很好的的溶解性。     

氧化温度和分散剂种类对Si3N4浆料性能的影响

研究了自蔓延燃烧合成Si₃N₄粉的氧化处理（在空气气氛中分别于400、600、800℃保温3 h）以及添加的分散剂种类（分别为聚丙烯酸钠、六偏磷酸钠、三聚磷酸钠、木质素磺酸钙）对制备的Si₃N₄浆料的抗沉降性、ζ电位和黏度的影响。结果表明：1)在空气气氛中于800℃保温3 h氧化处理后,粉体中Si₂N₂O含量增多;用其制备的浆料的稳定性最好,ζ电位绝对值较大,黏度最小。2)以六偏磷酸钠作为分散剂制备的Si₃N₄浆料的稳定性较好,ζ电位绝对值最大,黏度最小。3)添加0.021%（w）六偏磷酸钠制备的Si₃N₄浆料的ζ电位绝对值最大,黏度较小。     

分析化学实验绿色化探索——以铁含量测定为例

探索分析化学实验教学绿色化对于培养学生的环保意识和创新能力具有重要意义.本文以"铁含量测定"这一实验项目为例,从绿色试剂替代重金属及有毒试剂出发,探讨了实验教学绿色化的可行性.结果表明,采用抗坏血酸做还原剂结合分光光度法测定铁含量不仅可以替代有毒试剂、降低试剂消耗,而且适用于固体和液体样品;新方案稳定性和重现性好,适用...     

Synthesis of metal‐free poly(p‐dioxanone) by phosphazene base catalyzed ring‐opening polymerization

Poly(p‐dioxanone) (PPDO) has received significant attention due to its good biocompatibility and fast biodegradation profiles. In addition, PPDO is a polymer with high potential in biomedical applications. However, the conventional syntheses of PPDO via the ring‐opening polymerization (ROP) of p‐dioxanone (PDO) often use a metallic catalyst, which significantly limits its biorelated applications. This investigation was focused on the synthesis of metal‐free PPDO by using phosphazene base t‐BuP₄ as the catalyst. The effects of the reaction conditions including temperature, reaction time, initiators, and feed molar ratios were studied in detail by nuclear magnetic resonance spectroscopy, viscosimetry, differential scanning calorimetry, and thermogravimetric analysis. The results showed that t‐BuP₄ exhibited especially high activity in catalyzing alcohol or aniline to initiate the ROP of PDO, consequently resulting in metal‐free PPDOs. The polymerization was optimum at a reaction temperature of approximately 100°C and 88.7% of PDO was consumed. The viscosity–average molecular weights of the resulting polymer reached as high as 2.09 × 10⁴ g/mol. The molar ratios of [PDO]/[t‐BuP₄] also had an obvious effect on both the polymerization and the resulting polymer. Increasing [PDO]/[t‐BuP₄] ratios facilitated the molecular weight growth, whereas the conversions of PDO significantly decreased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43030.     

Rational design on photoelectrodes and devices to boost photoelectrochemical performance of solar-driven water splitting: a mini review

As an eco-friendly, efficient, and low-cost technique, photoelectrochemical water splitting has attracted growing interest in the production of clean and sustainable hydrogen by the conversion of abundant solar energy. In the photoelectrochemical system, the photoelectrode plays a vital role in absorbing the energy of sunlight to trigger the water splitting process and the overall efficiency depends largely on the integration and design of photoelectrochemical devices. In recent years, the optimization of photoelectrodes and photoelectrochemical devices to achieve highly efficient hydrogen production has been extensively investigated. In this paper, a concise review of recent advances in the modification of nanostructured photoelectrodes and the design of photoelectrochemical devices is presented. Meanwhile, the general principles of structural and morphological factors in altering the photoelectrochemical performance of photoelectrodes are discussed. Furthermore, the performance indicators and first principles to describe the behaviors of charge carriers are analyzed, which will be of profound guiding significance to increasing the overall efficiency of the photoelectrochemical water splitting system. Finally, current challenges and prospects for an in-depth understanding of reaction mechanisms using advanced characterization technologies and potential strategies for developing novel photoelectrodes and advanced photoelectrochemical water splitting devices are demonstrated.