摘要：The effect of depressurizing speed on mold filling behavior and entrainment of oxide film of A356 alloy was studied. Themold filling behavior and velocity fields were recorded by water simulation with particle image velocimetry. The results show thatthe gate velocity first increased dramatically, then changed with the depressurizing speed: the gate velocity increased slowly atrelatively high depressurizing speed; at reasonable depressurizing speed, the gate velocity kept unchanged; while at lowerdepressurizing speed, the gate velocity decreased firstly and then kept unchanged. High gate velocity results in melt falling backunder gravity at higher speed. The falling velocity is the main factor of oxide film entrainment in vacuum suction casting. The designcriterion of depressurizing rate was deduced, and the A356 alloy castings were poured to test the formula. The four-point bend testand Weibull probability plots were applied to assessing the fracture mechanisms of the as-cast A356 alloy. The results illuminate amethod on designing suitable depressurizing speed for mold filling in vacuum suction casting.

摘要：The role of carbodiimide as dehydrant in the chemo‐,regio‐and stereoselective Pd(Ⅱ/0)‐catalyzed hydrocarboxylation of various alkynes with HCOOH releasing CO in situ is reported for the first time to obtainα,β‐unsaturated carboxylic *** symmetrical and unsymmetrical monoalkynes show good ***,2,2’‐(1,4‐phenylene)diacrylic acid can also be synthesized in high yield through the dihydrocarboxylation of 1,4‐***,an excellent result in gram scale experiment and TON up to 900 can be obtained,displaying the efficiency of this ***,regulating the types and concentrations of dehydrant can control the CO generation,avoiding directly operating toxic CO and circumventing sensitivity issue to the CO *** the basis of the attractive features of formic acid including easy preparation through CO_(2) hydrogenation and efficient liberation of CO,this protocol using formic acid as bridging reagent between CO_(2) and CO can be perceived as an indirect utilization of CO_(2),offering an alternative method for preparing acrylic acid analogues.

摘要：分析了复杂多拐角工件电火花线切割加工中存在的问题,提出了有效的解决方案。从应用角度出发,设计了特殊的表层电极丝材料,优化了镀层丝的性能,满足了电火花线切割加工复杂多拐角工件的应用要求,提高了加工精度和表面质量。

摘要：高放废液中钯的萃取分离对贵金属钯资源的回收利用和核燃料循环中的玻璃固化过程都有重要意义,其关键在于高效高选择性萃取体系的开发和设计。基于氮杂环配体高效配合钯离子的特性,设计合成了一种具有吡啶-氧杂二氮唑结构的萃取剂6,6′-((4-异丁氧基吡啶-2,6-二基)双(1,2,4-氧杂二氮唑-5,3-二基))双(4-异丁氧基吡啶甲腈)(T2),用于酸性条件下钯离子的选择性萃取。以间硝基三氟甲苯为稀释剂且在1 mol/L 2-溴己酸存在下,配体T2对钯离子体现出较好的萃取能力。萃取动力学表明2 h即可萃取68%的钯进入有机相。该体系适用酸度广泛,在0.2~4 mol/L硝酸条件下均对钯展现出定量萃取,表明其优异的酸稳定性。此外,在多种阳离子共存的条件下,该体系能高选择性地分离萃取出钯离子,表明其良好的实际应用潜力。研究不仅提供了一类高效的钯萃取剂,更为其它新型钯萃取剂和萃取体系的开发提供了重要参考。

摘要：铯原子频率标准具有长期稳定性好、可靠性高的优点,在导航定位、守时授时、通信电力、时频计量等领域有着广泛的应用。近年来由于军事领域对高精度时间频率源的需求,铯原子频标的使用环境从实验室走向了战车、舰船等机动平台。本文针对铯原子频标在战车、舰船、高原等复杂环境下的环境适应性,研究环境因素对整机指标的影响机理。通过仿真与试验对整钟设计进行优化,以提高整机在力学、热、磁场、低气压等复杂环境下的适应性。经过优化设计后的国产铯束频率标准样机通过了相关环境试验项目的考核,各项指标均满足要求。研究结果表明,铯原子钟电性能样机的稳定度优于8.73×10^(-15)/5 d,磁敏感度3.15×10^(-14)/Gauss,工作温度特性-8.18×10^(-14),这项工作为国产化铯钟的进一步应用提供了基础。

摘要：此研究采用H_2O_2和TiO_2两种具有环保、绿色效应的物质作为催化剂,以超声/催化降解技术对水体中的1-甲基-3-丁基咪唑氯盐进行了处理,采用正交设计对实验条件进行了优化。实验结果表明:在20℃时,以过氧化氢作为催化剂在超声强度为10%时为最优条件,催化降解1-甲基-3-丁基咪唑氯盐的降解率较高,超声降解研究效果相对较好。

摘要：目的:对我国药品上市许可持有人(MAH)制度实施过程中的关键问题及解决思路进行业内调研,为提出完善我国MAH制度实施路径的建议提供支持。方法:结合对我国MAH制度相关法规和实施过程中关键问题的梳理,以及对欧盟、美国、日本等国家和地区MAH监管体系的深入研究,提取了法规、监管制度及责任赔偿方面的关键问题,设计调研问卷,以医药行业专业人员为目标调研对象开展定向调研,并对调查结果进行分析。结果与结论:调研结果表明,多数调研对象对我国MAH制度在药品全生命周期各环节落地实施过程中的关键问题与解决思路有一定共识,同时也反映出部分关键问题的解决思路仍需要进一步探索。

摘要：A polymeric hydroxyl ferric phosphate(PHFP)was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline *** PHFP was used to immobilize lead(Pb)and cadmium(Cd)in *** transform infrared spectra,X-ray diffraction were applied to revealing the characteristics of PHFP,and the modified Tessier sequential extraction and column leaching experiment with simulated acid rain were used to assess the effectiveness of immobilization of Cd and Pb in soils by *** results showed that PHFP was indeed a polymer with complicated OH-Fe-P structure and consisted of Fe6(OH)5(H2O)4(PO4)4(H2O)2and Fe25(PO4)14(OH)***,the removal rates of DTPA-extractable Cd and Pb in soils reached up to33%and45%,and the water-soluble Cd and Pb decreased by56%and58%,respectively,when PHFP was added in soils at4%*** addition,the immobilization of Cd and Pb contributed to transforming water soluble,exchangeable and carbonate-bonded fractions to Fe and Mn oxides-bonded,organic-bonded and residual *** leaching with simulated acid rain,Cd and Pb release amount in PHFP amended soil declined by53%and52%,respectively,as compared with non-treated *** result implied that PHFP had a potential application for the remediation of Cd-and Pb-contaminated soils.

摘要：中子辐射俘获反应在反应堆运行、核装置设计及核天体物理研究中起重要的作用.4πBaF_(2)探测装置有着高时间分辨能力、低中子灵敏度、高探测效率等优点,适合开展中子辐射俘获反应截面数据的测量.中国原子能科学研究院核数据重点实验室建立了伽马全吸收装置(Gamma total absorption facility,GTAF),该装置用28块六棱BaF_(2)晶体和12块五棱BaF_(2)晶体构成了外径25 cm,内径10 cm的球壳,覆盖了95.2%的立体角.利用GTAF在中国散裂中子源Back-n束线上,测量了197Au(n,γ)的反应截面数据.测量数据通过能量筛选、PSD方法、晶体多重性筛选进行了初步本底扣除,随后结合对^(nat)C及空样品的测量数据对本底进行了分析及扣除,获得了197Au俘获反应的产额,利用SAMMY程序拟合得到了^(197)Au在1—100 e V的共振能量、中子共振宽度和伽马共振宽度参数.实验测量结果与ENDF/B-VIII.0数据库符合良好,其共振参数存在一定差异,分析原因可能与GTAF能量分辨率、Back-n的中子能谱测量精度、以及实验本底扣除方法相关,这也是下一步工作的重点.

摘要：提出了一种悬置双微带曲折线慢波结构,介质基板悬置于封闭金属腔内,基板上下表面各镀有一条金属曲折线结构。该结构具有双电子束通道,电磁波具有对称的分布,因此,电磁波可以通过上下腔体与两束带状电子束互作用。通过仿真软件分析了其高频特性,设计工作电压和电流分别为2050 V和0.2 A,PIC仿真结果表明,在36 GHz处最大输出增益为26 dB,具有8 GHz的3-dB饱和功率带宽。实验测得该慢波结构反射损耗低于-10 dB,同时分析了慢波结构制备过程中影响传输损耗的主要因素。