Magnetic Fluctuation Measurement in Sino United Spherical Tokamak Plasma

To investigate the magnetic fluctuations and for further transport study, the poloidal and radial magnetic field t is conducted on the Sino United Spherical Tokamak （SUNIST）. Auto-power spectral density indicares that the magnetic fiuctuation energy mainly concentrates in the frequency region lower than lO kttz. The magnetic field oscillations, which are characterized by harmonic frequencies of 40 kHz, are observed in the scrape- off layer; by contrast, in the plasma core, the magnetic fluctuations are of Gaussian type. The time-frequency profiles show that the poloidal magnetic fluctuations are temporally intermittent. The autocorrelation calculation indicates that the fluctuations in decorrelation time vary between the core and the edge.     

硝酸乙酯分子间相互作用的ab initio研究

在abinitio-HF/6-31G水平上求得硝酸乙酯二聚体势能面上的四种优化构型和电子结构。经MP2电子相关校正和基组叠加误差(BSSE)以及零点能(ZPE)校正，求得二聚体的最大结合能为11.46kJ.mol^-^1，还进行HF/6-311G和HF/6-311++G水平的总能量比较计算，发现6-31G基组对计算结合能比较适合，二子体系间的电荷转移很少，对优化构型进行振动分析，并基于统计热力学求得从单体形成二聚体的热力学性质变化。     

取代吡唑-5-酰基杂环衍生物的合成、结构与生物活性

为了寻求新的含吡唑双杂环先导化合物. 用4-取代-1-甲基-3-乙基-5-吡唑甲酰氯与2-噻唑烷酮、2-噻唑硫酮、2-噁唑烷酮等含氮杂环反应得到了12个含吡唑环的双杂环化合物. 化合物结构用IR, ¹H NMR, MS和元素分析进行了表征. 并用X射线单晶衍射法测定了化合物3-(1-甲基-3-乙基-4-硝基-5-吡唑甲酰基)-噁唑烷-2-酮(3k)的晶体结构. 晶体为单斜晶系, P2₁/n (#14)空间群, a＝1.52175(3) nm, b＝0.52970(1) nm, c＝1.58185(3) nm, β＝104.893(4), V＝1.2323(4) nm³, Z＝4, D_c＝1.45 g/cm³, F(000)＝560.00, R₁＝0.064, wR₂＝0.193. 初步生物活性实验结果表明, 在25 mg/L浓度下, 3-(1-甲基-3-乙基-4-硝基-5-吡唑甲酰基)-噻唑烷-2-酮(3c), 3-(1-甲基-3-乙基-4-硝基-5-吡唑甲酰基)-噻唑烷-2-硫酮(3g)对水稻稻瘟病菌(Pyricularia oryzae)的抑制活性达到40%. 在500 mg/L浓度下, 3-(1-甲基-3-乙基-4-溴-5-吡唑甲酰基)-噻唑烷-2-酮(3d), 3-(1-甲基-3-乙基-4-溴-5-吡唑甲酰基)-噁唑烷-2-酮(3l)对稻黑尾叶蝉(Nephotettix cinc-ticeps)的抑制活性达到53.37%.     

改变枸橼酸和EDTA抗衡阳离子对草酸钙结石抑制作用的体外模拟

The effects of counterions of citric acid and EDTA on the crystallization of calcium oxalate (CaO_x) were in-vestigated in silica gel with a double diffusion technique. The ability of inhibiting the growth and aggregation of CaO_x crystal and the ability of inducing formation of COD follows： potassium citrate 》 sodium citrate >citric acid. Na₂EDTA had a stronger ability to inhibit the aggregation of CaO_x crystals than that of EDTA， but a weaker ability to inhibit nucleation and growth of CaO_x crystals. Since COM exhibits a greater degree of attachment to renal tubule cells in culture compared with COD， that is， COD is easy to be expelled from the body along with the urine. So both inducing formation of COD and inhibiting growth and aggregation of CaO_x crystal can decrease the probability of urinary stones. These results have positive significance in the prevention and cure of urinary stones clinically.     

泰勒公式及泰勒级数之妙用

泰勒公式及泰勒级数是非常重要的数学工具,除了读者熟知的应用方面外,在其他问题的解决中也有妙用.举例介绍了应用泰勒公式及泰勒级数解决判断级数的敛散性、证明与积分有关的不等式等问题.     

Quasi-Dammann grating with proportional intensity of array spots for surface hardening of metal

For surface hardening of metal,a quasi-Dammann grating (QDG) is proposed and fabricated to generate array spots with proportional-intensity distribution.To get uniformly hardened band distribution and improve the wear resistance of the sample surface,a three-order QDG is designed to produce array spots with enhanced intensity in the edge.The design and fabrication of the QDG are described in detail.The surface profile of the fabricated grating was measured,which shows that the fabrication error is less than...     

0.3%胺菊酯·右旋苯醚菊酯气雾剂的高效液相色谱分析

提出了采用高效液相色谱法,使用Hypersil C18不锈钢色谱柱和乙腈-水(85+15)混合溶液为流动相进行分离,并用紫外检测器在220 nm波长处同时测定胺菊酯和右旋苯醚菊酯,此方法用作上述两杀虫剂的复合制剂0.3%胺菊酯.右旋苯醚菊酯气雾剂的质量监控分析方法。测得两化合物的相对标准偏差(n=5)依次为0.86%和2.6%,回收率依次在94.7%~105.5%和92.8%~102.9%之间。     

水杨酸甲酯制备实验的改进

"水杨酸甲酯的制备"是一个经典的有机化学实验，作为考核实验考查学生操作技能，并根据产品的质量和纯度给予学生成绩。教材中提供的实验方案不合理，导致学生制备产品的收率很低。对传统实验方法的不足之处进行分析，提出了先用碳酸钠中和硫酸（去除催化剂），再蒸馏分离甲醇的实验路线。改进的实验方案设计更合理，避免了水杨酸甲酯分解，提高了产品的收率，达到了良好的教学效果。     

基于精氨酸酶切的蛋白质C端肽段富集方法的优化及评估北大核心CSCD

基于聚合物的蛋白质C端反向富集策略是用于研究蛋白质C端最为广泛的策略之一。目前,基于胰蛋白酶(trypsin)切割精氨酸残基C端(ArgC型酶切)的蛋白C端组学方法对蛋白质C端的鉴定深度仍有待提高。为解决这一问题,该研究对此方法进行了优化和评估:建立了基于“V型”过滤装置的“一锅法”富集流程,避免了副反应的干扰,缩短了样本的制备时间;优化了蛋白水平乙酰化反应条件,最大限度地降低了丝氨酸、苏氨酸、酪氨酸残基上的副反应,提高了肽段鉴定的可信性;优化了基于固相萃取枪头膜片过滤柱(StageTip柱)的样品分离过程,使C端肽段的鉴定深度增加至原来的4倍。通过以上优化,按照肽段水平错误发现率(FDR)<0.01、离子分数(ion score)≥20,且C端带有乙醇胺修饰的数据筛选标准,从人HEK 293T细胞中共鉴定出696个蛋白质C端。若仅要求肽段水平FDR<0.01,鉴定数目进一步增加到933个,这是基于聚合物富集策略的蛋白质C端组学方法所得的最大数据集之一。探索了胰蛋白酶镜像酶(LysargiNase)切割精氨酸残基N端(ArgN型酶切)与不同肽段N端衍生化修饰组合对蛋白质C端鉴定数目和种类的影响,“LysargiNase酶切+肽段N端乙酰化”新策略在原有“胰蛋白酶酶切+肽段N端二甲基化”策略的基础上将鉴定蛋白质C端的种类提升了47%。综上,该研究通过对基于Arg型酶切的蛋白C端组学方法的优化,提升了C端肽段的鉴定深度,扩大了C端肽段鉴定的覆盖范围。该方法将有望成为系统性表征蛋白质C端的有力工具。