Production of neutron-rich actinide isotopes in isobaric collisions via multinucleon transfer reactions

We systematically calculated the multinucleon transfer reactions of ^(208)Os,^(208)Pt,^(208)Hg,^(208)Pb,^(208)Po,^(208)Rn,^(208)Ra,and ^(132,136) Xe when bombarded on ^(232) Th and ^(248) Cm at Coulomb barrier energies within the dinuclear system model.These results are in good agreement with the available experimental data.The influence of Coulomb and shell effects on actinide production in these reactions has been rigorously studied.We calculated and analyzed the potential energy surface (PES) and total kinetic energy (TKE) mass distributions for the reactions involving ^(208)Hg,^(208)Pb,and ^(208) Po with ^(248) Cm and ^(232)Th.The PES and TKE spectra shed light on the fragment formation mechanisms in multinucleon transfer reactions,with clear indications of isospin and shell effects.The production cross sections for multinucleon transfer products show a strong dependence on isobar projectiles with a mass number A=208.Isobar projectiles with high N/Z ratios are advantageous for generating neutron-rich target-like fragments.Conversely,products induced by isobar projectiles with larger charge numbers tend to shift toward proton-rich regions.The intertwining of the Coulomb potential and shell effect is evident in the production cross sections of actinide isotopes.Drawing from reactions induced by radioactive projectiles,we anticipate the discovery of several new actinide isotopes near the nuclear drip lines,extending our reach into the superheavy nuclei domain.

Product polarization and mechanism of Li + HF(v=0, j=0) → LiF(v', j') + H collision reaction

A state-to-state dynamics analysis for the Li＋HF （v = 0, j = 0）→LiF （v’, j’）＋H collision reaction has been performed through quasiclassical trajectory （QCT） calculations. It is found that the differential cross section （DCS） of the LiF products from the title reaction is preferentially backward scattering for v’=0, yet forward scattering for v’=1 and 2. For v’=3, the DCS exhibits forward, backward, and sideways scatterings. The variation of the internuclear distances and angles along the propagation time reveals that more than 99.08% of reaction trajectories undergo the direct reaction mechanism. The values of the polarization parameters a1-{1} and a0{2} demonstrate that the product rotational angular moment j’ is not only aligned perpendicular to the reagent relative velocity vector k, but also oriented along the negative y axis. These product polarization results agree well with the recent quantum mechanical studies. The mechanism of these results was proposed and discussed in detail.

Enhanced single-nanoparticle collisions for the hydrogen evolution reaction in a confined microchannel

Single nanoparticle(NP)collisions technique has been widely employed in electrocatalysis.However,the short collision duration of single NPs hinders the further improvement in their electrocatalytic performance.Here,to increase the dynamic collision duration of single NPs in the electron tunneling region,enhanced near-wall hindered diffusion is introduced in the stochastic collision process by coupling a Au ultramicroelectrode(UME)with a confined microchannel.In the case of single palladium nanoparticle(Pd NP)collisions for the hydrogen evolution reaction(HER),the hydrodynamic trapping confined in the microchannel effectively permits the activation of the HER on the single Pd NPs.The microchannel-based Au UME is promising in the application of single-NP collisions to energy conversion.

Differential Cross Sections of F+HD→DF+H Reaction at Collision Energies from 3.03 meV to 17.97 meV

The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant contributions from both the BornOppenheimer(BO)forbidden reaction F^(*)(^(2)P_(1/2))+HD→DF+H and the BO-allowed reaction F(^(2)P_(3/2))+HD→DF+H were observed.In the backward scattering direction,the contribution from the BO-forbidden reaction F^(*)(^(2)P_(1/2))+HD was found to be considerably greater than the BO-allowed reaction F(^(2)P_(3/2))+HD,indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies.Collision-energy dependence of differential cross sections(DCSs)in the backward scattering direction was found to be monotonously decreased as the collision energy decreases,which does not support the existence of resonance states in this energy range.DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV.It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV,suggesting some unknown mechanisms may exist at low collision energies.

THEORETICAL INVESTIGATION OF COLLISION ENERGY EFFECT ON REACTION O(?) BARIUM WITH METHYL BROMIDE

The reac dynamics on Ba+BrCH_3→BaBr+CH_3 has been investigated in the first proposed potential energy surface of the generalized LEPS type,using the quasiclassical trajectory method.In simulation of the conditions in molecular beam experiments,the results of the present study show significant effect of the reagent collision energy on the dynamics of the reaction,and are in good agreement with the experimental ones.

Stereodynamics Study of Li+HF→LiF+H Reactions on X^2A’ Potential Energy Surface at Collision Energies below 5.00 kcal/mol

The product rotational polarizations of reaction Li-SHF→LiF-kH at different collision energies, as well as at the different vibrational states and rotational states, are calculated by using the quasi-classical trajectory method based on a new potential energy surface constructed by Aguado et al. [J. Chem. Phys. 119（2003） 10088]. We investigate the Mignment and the orientation of the product molecule by calculating the P（θr, φr） distribu- tions describing polar angle distribution, the P（θr） distributions describing the k-j＇ correlation and the P（φr） distributions describing the k-k＇-j＇ correlation. We also explore the dependence of reaction probabilities and cross sections on the rotational and vibrational quantum number of the title reaction. It is concluded that the vibrational state has more important impact on the angular distribution, reaction probability and cross section.

Methodology of Wavelets in Relativistic Heavy Ion Collisions in One Dimensional Phase Space (<i>η</i>-Space)

An attempt has been made to apply the wavelet methodology for the study of the results of the chaotic behavior of multiparticle production in relativistic heavy ion collisions. We reviewed the data that describes the collisions of relativistic heavy ion for the case η-space in 1-D phase space of variable. We compared the experimental data and UrQMD data using wavelet coherency. We discussed the results of the comparison.

Rapidity and Pseudorapidity Distributions of theVarious Hadron-Species Produced in High EnergyNuclear Collisions: A Systematic Approach

With the help of a phenomenological approach outlined in the text in some detail, we have dealt here with the description of the plots on rapidity and pseudorapidity spectra of some hadron-secondaries produced in various nucleus-nucleus interactions at high energies. The agreement between the measured data and the attempted fits are, on the whole, modestly satisfactory excepting a very narrow central region in the vicinity of y = η = 0. At last, hints to how the steps suggested in the main body of the text to proceed with the description of the measured data given in the plots could lead finally to a somewhat systematic methodology have also been made.

The Fundamental Mechanism for the Collision/Pressure Induced Optic Effect

In this work, the fundamental mechanism regarding the collision and pressure induced optic effect is elucidated. Based on the concept of the collision-relaxation/the pressure-release induced optic effect put forth here, a new laser technology may be developed. Furthermore, our work also makes the understanding the photon involved chemical reaction become much clear and rationalized.

ICP-MS/MS测定轻质油中痕量氯含量

基于H_(2)反应模式下的质量转移反应消除干扰,建立电感耦合等离子体串联质谱(ICP-MS/MS)测定轻质油中痕量Cl的分析方法。轻质油经简单稀释后直接采用ICP-MS/MS进行测定,在MS/MS模式下使用H_(2)作为反应气,利用在碰撞/反应池(CRC)中Cl^(+)与H_(2)发生二次H原子转移反应形成的子离子(H_(2)Cl^(+))进行测定,消除所有质谱干扰,获得Cl的灵敏度和检出限(LOD)明显优于O_(2)反应模式,LOD低至7.56μg/kg。通过与扇型磁场ICP-MS(SF-ICP-MS)对比分析标准参考物质NIST SRM 1634c,评价方法的准确可靠性。结果表明,标准参考物质的分析结果与认证值基本一致,相对标准偏差(RSD)为3.1%~4.7%,2种方法的对比分析结果在95%的置信度水平无显著性差异。所建立分析方法的灵敏度、准确度和和精密度高,MS/MS模式和H_(2)质量转移法的结合可无干扰测定轻质油中的Cl,适用于轻质油中痕量Cl的质量控制与评估。

碰撞/反应池电感耦合等离子体质谱(ICP-MS)法测定血液中16种元素

采用直接稀释法,使用电感耦合等离子体质谱仪测定血液中元素的过程中,由于血液样本成分复杂,容易产生较大的基体效应,同时一系列多原子离子(例如,^(40)Ar^(16)O^(+)、^(40)Ar^(40)Ar^(+)等)会影响与其有相同质荷比核素的检测,进而影响测定结果。通过使电感耦合等离子体质谱仪(ICP-MS)分别工作在标准模式、氦气模式和氢气模式下,对比仪器的氧化物离子产率(CeO/Ce)、双电荷离子产率(Ba^(++)/Ba)、灵敏度与检出限情况,同时对氢气模式时仪器上述指标优于其他两种模式的潜在机理进行分析;随后再使用氢气作为碰撞/反应池气体,使用直接稀释法分析全血标准品以及小鼠血液样本中16种元素的含量情况。结果表明,使用氢气作为碰撞/反应池气体时,氧化物离子产率(CeO/Ce)、双电荷离子产率(Ba^(++)/Ba)、灵敏度与检出限情况优于标准模式和氦气模式,且16种元素在0.5~100.0μg/L线性关系良好(R2≥0.99991),对全血标准品中分析准确度为86.0%~114%,分析小鼠血液样本时的加标回收率为81.2%~115%,仪器精密度为2.3%~4.8%,使用氢气作为电感耦合等离子体质谱仪技术的碰撞/反应池气体,为分析血液样品中16种元素(V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Ge、As、Se、Cd、Hg、Tl、Pb、Bi)开发一种新的分析方法,也为血液金属组学分析提供了新方法。

防撞鸟巢式护理联合腹部按摩在新生儿高胆红素血症患儿中的应用

目的探讨防撞鸟巢式护理联合腹部按摩在新生儿高胆红素血症患儿中的应用效果。方法58例接受蓝光治疗的新生儿高胆红素血症患儿随机分为两组。参照组实施常规护理干预,研究组实施防撞鸟巢式护理联合腹部按摩干预。比较两组的哭闹时间、高胆红素血症消退时间、睡眠时间以及不良反应。结果研究组的哭闹时间、高胆红素血症消退时间均短于参照组,睡眠时间长于参照组(P<0.05)。研究组的不良反应总发生率为3.45%,低于参照组的27.59%(P<0.05)。结论防撞鸟巢式护理联合腹部按摩可明显延长新生儿高胆红素血症患儿的睡眠时间,缩短其哭闹时间和高胆红素血症消失时间,减少不良反应的发生。

Generation and Applications of a Broad Atomic Oxygen Beam with a High Flux-Density via Collision-lnduced Dissociation of O_(2)

We detail the generation of a pulsed atomic oxygen(AO)broad beam with a high flux-density via collision-induced dissociation of O_(2) to support practical industrial exploitation of AOs,particularly for facilitating 2-dimenstional oxidation/etching at a fast rate of one-monolayer per second in an area≥1000 cm².This innovation fuses the following interdisciplinary concepts:(a)a high density of O^(*) can be produced in an electron-cyclotron-resonance(ECR)O2 plasma;(b)o^(*) can be extracted and accelerated with an aperture-electrode in the plasma.

Droplet collision of hypergolic propellants

In the present mini-review,droplet impacting on a liquid pool,jet impingement,and binary droplet collision of nonreacting liquids are first summarized in terms of basic phenomena and the corresponding nondimensional parameters.Then,two representative hypergolic bipropellant systems,a hypergolic fuel of N,N,N′,N′-tetramethylethylenediamine(TMEDA)and an oxidizer of white fuming nitric acid(WFNA)and a monoethanolamine-based fuel(MEA-NaBH4)and a high-density hydrogen peroxide(H2O2),are discussed in detail to unveil the rich underlying physics such as liquid-phase reaction,heat transfer,phase change,and gas-phase reaction.This review focuses on quantifying and interpreting the parametric dependence of the gas-phase ignition induced by droplet collision of liquid hypergolic propellants.The advances in droplet collision of hypergolic propellants are important for modeling the real hypergolic impinging-jet(spray)combustion and for the design optimization of orbit-maneuver rocket engines.

A Trade-off between Solvation and Collision Activation in Steering Competing E2 and S_(N)2 Dynamics

The prototypical E2 elimination and SN2 sub-stitution reactions between microsolvated fluoride and ethyl bromide show unexpected dynamic behaviors in mechanistic evolution driven by solvation and collision activation.Considering the steric effects,the gas-phase selectivity favors an E2 pathway barely dependent on collision energies.Remarkably,base solvation steers the reaction in an effective way toward substitution at a near-thermal energy,whereas the governing high-energy events retain elimination.Chemical dynamics simulations reproduce exper-imental findings and uncover a crucial solute-solvent coupling in determining such competing processes.Interestingly,collision activation can tune the underlying atomistic dynamics essentially in the reactant entrance channel and cause a mechanism shift.These features for the ubiquitous competing E2/SN2 dynamics remain quite unknown,providing unique insight into reaction selectivity for complex chemical networks.

微波消解-电感耦合等离子体质谱(ICP-MS)法测定稀释沥青中23种元素

稀释沥青是一种中间产品,主要用于生产沥青。目前测定稀释沥青中元素含量的方法较少,前处理过程繁琐。通过优化样品称样量、消解试剂、赶酸温度,选择合适的前处理方式;通过引入内标元素对非质谱干扰进行校正;通过调谐优化仪器参数,选择碰撞反应池He模式,采用干扰方程,选择合适同位素等手段对质谱干扰进行了校正;采用45 Sc、72 Ge、115 In、209 Bi作为内标元素,对方法的检出限、精密度、准确度等进行考察,建立了微波消解-电感耦合等离子体质谱法同时测定稀释沥青中铝、钒、铬、锰、铁、钴等23种元素的方法。在优化的实验条件下,23种元素在一定的质量浓度范围内与其信号强度呈线性关系,标准曲线线性良好,相关系数在0.999~1.000,方法的检出限在0.0005~1.0 mg/kg,方法用加标回收测定回收率,加标回收率在80.0%~110%,对稀释沥青样品平行测定7次,测定值的相对标准偏差在0.47%~3.1%。对进口稀释沥青中23种元素进行测定,满足国家标准对各项技术指标参数的要求,检出限低,选择性好,结果准确可靠,为稀释沥青类样品中多种元素分析测定提供了新的参考方法。

ICP-MS法测定镍铂合金中17个杂质元素

试样以盐酸-硝酸溶解,建立了电感耦合等离子体质谱法(ICP-MS)测定镍铂合金中17个杂质元素的方法。采用标准模式测定Mg、Al、Ti、Cr、Mn、Co、Zn、Cu、Zr、Pd、Ag、Sn、Sm、和Pb,氨气反应模式测定Si和Fe(氨气流速分别为0.2和0.25mL/min);氦气反应模式测定V(氦气流速为5mL/min,考察了基体效应对测定结果的影响,采用内标校正提高分析的准确性,其中Mg、Al、Ti、Cr、V、Mn、Fe、Co、Zn和Si以Sc为内标,Cu、Zr、Pd、Ag和Sn以Y为内标,Sm和Pb以Re为内标。测定各元素的线性相关系数(r)不小于0.9996,方法检出限为0.0025~0.78ng/mL。对NiPt5、NiPt15、NiPt60样品中17个杂质元素进行测定,相对标准偏差(RSD)为0.86%~13.07%,加标回收率89.0%~116.5%,方法满足镍铂合金靶材的测定要求。

电感耦合等离子体质谱法测定电镀废水中的9种金属元素

为利用电感耦合等离子体质谱法(ICP-MS)实现电镀废水中微量元素的准确测定分析,通过优化碰撞反应池氦气流量实现干扰的有效扣除,为了减小测试的记忆效应以及实现待测试样的长期稳定测试,优化Au浓度占比达到良好稳定的测试效果。该方法对电镀废水直接测定,结果表明,各元素线性相关系数(R 2)均大于0.999,方法检出限为0.012~0.126μg/L,精密度均低于4.40%,试验样本加标回收率均在89.7%~107.5%。该分析方法具有操作简便、准确度好、灵敏度高等优点,对于电镀废水中的微量元素可以快速准确定量,可为电镀行业助力,也可为环境样本低含量元素的应用检测技术提供技术指导和借鉴。

碰撞激活诱导的双势阱势能面可以实现9-甲基-8-氧鸟嘌呤-9-甲基腺嘌呤碱基对阳离子自由基的质子转移

8-氧鸟嘌呤(OG)是最常见的核碱基氧化损伤,它在复制过程中可以用Hoogsteen的模式与腺嘌呤(A)错误配对.0G.A碱基对不仅可以诱发G·C→T·A的颠换突变,而且由于OG的电离势和氧化电位低于天然DNA碱基更容易受到电离辐射和单电子氧化的影响,本文报道了[9MOG·9MA]^(·+)碱華对阳离子自由基的形成.和碰撞诱导解离,该碱基对利用9-甲基8-氧鸟嘌呤(9MOG)和9-甲基腺嘌呤(9MA)模拟相对应的核苷酸.实验通过电喷雾产生Cu(Ⅱ)碱基复合物继之以氧化分离产生[9MOG·9MA]^(·+),并使用导向离子束串级质谱仪检测[9MOG·9MA]^(·+)的碰撞诱导解离、通过测量在不同碰撞能量下的解离产物和反应截面,可以得出[9MOG-H]+[9MA+H]^(+)(主要解离通道)和9MOG^(·+)+9MA(次要通道)的0 K解离阈能分别为1.8和1.65 eV.使用密度泛函理论对[9MOG·9MA]^(·+)的结构计算发现其所有重要构象都发生了质子转移生成[9MOG-H]^(·)·[9MA+H]^(+).另一方面,9MOG^(·+)+9MA的解离通道却需要9MOG^(·+)9MA作为中间体.看似矛盾的结果可以用碰撞活化后反应势能面上出现的双重势阱和由此触发的激发态质子转移平衡([9MOG-H]^(·)·[9MA+H]^(+))^(*)→←(9MOG6(·+)·9MA)^(*)来解释.本文实验和理论研究揭示了这种生物学上重要的非规范碱基对如何在氧化和电离损伤时发生解离.

三重四级杆-电感耦合等离子体质谱法测定高纯三氧化二铈中14种稀土元素

在高纯稀土分析中,通常利用C272微型柱分离或TODGA分离基体富集待测元素,但此方法效率低、操作难度大,容易引入外部杂质和洗脱不完全导致结果出现偏差。本文建立了三重四级杆电感耦合等离子体质谱(ICP-MS/MS)对高纯三氧化二铈(Ce_(2)O_(3))中杂质稀土元素测试方法,利用碰撞模式测定稀土氧化铈中的Y、La、Nd、Sm、Eu、Dy、Ho、Er、Tm、Yb、Lu,质量转移模式测定氧化铈中的Pr、Gd、Tb。测试采用0.1%基体进样,在MS/MS模式下,以笑气(N2O)为反应气,通过O原子和N原子的质量转移反应,可以有效克服高基体对待测元素带来质谱干扰,实现高纯Ce_(2)O_(3)中14种杂质稀土元素准确测定。试验结果表明,在优化试验条件下,14种元素的检出限为0.001~0.020 mg/kg,加标回收率在81.2%~105.3%之间。该方法仅使用N2O一种反应气,且无需基体分离,可以快速、准确测定高纯稀土氧化物中杂质元素,为高纯稀土杂质元素分析提供思路。