反馈控制棘轮的定向输运效率研究

研究了反馈耦合布朗棘轮中粒子处于负载力、时变外力及噪声作用下的定向输运问题.详细讨论了外力作用时间的不对称性、外势空间的不对称性及外力周期等对反馈耦合棘轮中粒子输运效率的影响.研究发现,外力的时间不对称度能促进反馈棘轮中粒子的定向输运,随时间不对称度的增大,反馈棘轮中粒子能获得较大的效率.然而,外势空间的不对称度能有效抑制耦合棘轮中粒子的扩散,达到增强耦合粒子定向输运的效果.同时还发现,存在最优的噪声强度能使耦合粒子的输运效率达到最大.     

Synthesis,Structure,and Magnetic Property of One Novel Entangled Cobalt~Ⅱ-organic Compound

One novel entangled cobalt compound,{[Co 3 (nbta) 2 (4,4-bpy) 2 (H 2 O) 2 ](H 2 O) 2 } n (1,H 3 nbta=5-nitro-1,2,3-benzenetricarboxylic acid,4,4-bpy=4,4-bipyridyl),was prepared and characterized by X-ray diffraction,magnetism,elemental analysis,XPS,TGA and IR spectroscopy.The crystal of 1 crystallizes in monoclinic,space group Pc with a=13.0717(16),b=11.4167(14),c=15.9342(19),β=90.5190(10)o,V=2377.9(5)3,Z=2,C 48 H 36 Co 3 N 8 O 20,M r=1221.64,D c=1.706 g/cm 3,F(000)=1242 and μ(MoKα)=1.128 mm-1.The final R=0.0497 and wR=0.1461 for 4185 observed reflections with I > 2σ(I) and R=0.0721 and wR=0.1619 for all data.X-ray diffraction analyses revealed that Co(1) is linked by the nbta 3-ligands to form the ladder shape along the c axis,which is further extended into two-dimensional networks via the joint of Co(2) along the a axis.Moreover,these two dimensional motifs are interconnected by the 4,4-bpy bridges to form a complicated 3-D polymeric framework.Magnetic measurements revealed that compound 1 shows strong antiferromagnetic property.     

Syntheses, Crystal Structures, and Properties of Two Mixed-ligand Coordination Polymers： [Zn（bdc）（1,3-bimb）]_n and {[Mn_2（ox）_2（1,3,5-tib）_（4/3）]·4H_2O}_n

Two new coordination polymers,[Zn（bdc）（1,3-bimb）]n（1） and {[Mn2（ox）2（1,3,5tib）4/3]·4H2O}n（2）（H2ox = oxalic acid,H2bdc = terephthalic acid,1,3-bimb = 1,3-bis（imidazol-1ylmethyl）benzene,1,3,5-tib = 1,3,5-tri（imidazol-1-yl）benzene）,were synthesized and characterized by elemental analysis,IR,powder X-ray diffraction（PXRD）,and thermogravimetric（TG） analyses.X-ray diffracation analysis reveals that two kinds of zigzag chains [Zn（bdc）]n and [Zn（1,3-bimb）]n in compound 1 are interweaved to form a 3D 4-fold interpenetrated 66-dia framework.In compound 2,Mn（1） and Mn（2） are linked via 1,3,5-tib ligands to form two different nets of [Mn6（1,3,5-tib）6 ]n along the ab plane with inner-or outer-shape N–Mn–N angles,which are connected by 1D infinite [Mn2（ox）2 ]n chains via Mn–O bonds to result in a（3,3,3,4,4）-connected（4·8·10）3（4·82）3（4·83·102）6（82·104·3）3（83）4 topology.Moreover,the photoluminescence of 1 has been investigated.The crystal of 1 crystallizes in orthorhombic,space group Pna2 with a = 13.2267（6）,b = 9.1717（4）,c = 17.4492（8）,V = 2116.79（16）3,Z = 4,C22 H18N4O4 Zn,Mr = 467.77,Dc = 1.468 g/cm3,F（000） = 960 and μ（MoKα） = 1.197 mm-1.The final R = 0.0280 and wR = 0.0618 for 3695 observed reflections with I 2（I） and R = 0.0389 and wR = 0.0653 for all data.The crystal of 2 crystallizes in rhombohedral,space group R-3 with a = 22.080（8）,c = 31.19（2）,V = 13167（11） 3,Z = 18,C24 H25 Mn2 N8 O13,Mr = 743.40,Dc = 1.688 g/cm3,F（000） = 6822 and μ（MoKα） = 0.945 mm-1.The final R = 0.0429 and wR = 0.1035 for 5160 observed reflections with I 2（I） and R = 0.0824 and wR = 0.1244 for all data.     

气相色谱-串联质谱法同时测定土壤中5种取代脲类除草剂的含量北大核心CSCD

提出了气相色谱-串联质谱法同时测定土壤中利谷隆、异丙隆、伏草隆、敌草隆、戊菌隆等5种取代脲类除草剂含量的方法。称取10 g研磨、过筛后的土壤样品,加入10 mL水润湿,用20 mL乙腈和一包含4.0 g硫酸镁和1.0 g乙酸钠的QuEChERS萃取剂提取。取10 mL上清液至25 mL QuEChERS净化管(含1 g硫酸镁、500 mg N-丙基乙二胺和500 mg C_(18)吸附剂)中,涡旋,离心。取5 mL上清液,于50℃水浴中氮吹至近干,残渣用1 mL丙酮复溶后,过0.22μm微孔滤膜,滤液注入气相色谱仪,以Rxi-5Sil MS色谱柱为固定相,在程序升温条件下分离,所得目标物用三重四极杆串联质谱仪在电子轰击离子源以及多反应监测模式下检测,外标法定量。结果显示:利谷隆、异丙隆、伏草隆、敌草隆、戊菌隆在0.02~5.0 mg·L^(-1)内与其对应的峰面积呈线性关系,检出限(3S/N)为0.008~0.015 mg·kg^(-1);对空白土壤样品进行3个浓度水平的加标回收试验,回收率为87.2%~102%,测定值的相对标准偏差(n=6)为1.8%~3.5%;方法用于实际样品分析,在大豆种植土壤、蔬菜种植土壤中分别检出敌草隆和戊菌隆。