基于石墨烯/石墨烯卷轴复合薄膜高灵敏度柔性压力传感器

一维导电材料例如纳米线，大量应用于柔性压力传感器中. 但是一维材料和基底之间接触时相互作用力较弱，使得传感器灵敏度、响应时间、和循环寿命等性能指标有待进一步提高. 针对这些问题，设计了石墨烯/石墨烯卷轴多分子层复合薄膜作为传感器导电层. 石墨烯卷轴具有一维结构，而石墨烯的二维结构可以牢固地固定卷轴，以确保高导电性复合薄膜与基底之间的粘附性，同时整体结构的导电通道得到了增加. 由于一维和二维结构的协同效应，实现了应变灵敏度系数3.5 kPa^-1、 响应时间小于50 ms、能够稳定工作1000次以上的压阻传感器.     

Soliton molecules and the CRE method in the extended mKdV equation

The soliton molecules of the(1+1)-dimensional extended modified Korteweg–de Vries(mKdV)system are obtained by a new resonance condition, which is called velocity resonance. One soliton molecule and interaction between a soliton molecule and one-soliton are displayed by selecting suitable parameters. The soliton molecules including the bright and bright soliton, the dark and bright soliton, and the dark and dark soliton are exhibited in figures 1–3, respectively.Meanwhile, the nonlocal symmetry of the extended mKdV equation is derived by the truncated Painlevé method. The consistent Riccati expansion(CRE) method is applied to the extended mKdV equation. It demonstrates that the extended mKdV equation is a CRE solvable system. A nonauto-B?cklund theorem and interaction between one-soliton and cnoidal waves are generated by the CRE method.     

分数阶Schrodinger—Kirchhoff方程无穷多高能量解的存在性

本文研究如下带有变号势函数的分数阶Schrodinger Kirchhoff方程(a+b∫∫R^N|u(x)-u(y)|^p/|x-y|^N+p^sdxdy)^p-1(-△)p^su+λV(x)|u|^p-2u=f(x,u)-μg(x)|u|^q-2u,x∈R^N.其中s∈(0,1),p∈[2,∞),q∈(l,p),a,b>0,λ,μ>0均为正常数,在V,f,g等函数合适的条件下,运用喷泉定理获得该系统无穷多高能量解的存在性.     

Adsorption Site Regulation to Guide Atomic Design of Ni–Ga Catalysts for Acetylene Semi‐Hydrogenation

Atomic regulation of metal catalysts has emerged as an intriguing yet challenging strategy to boost product selectivity. Here, we report a density functional theory‐guided atomic design strategy for the fabrication of a NiGa intermetallic catalyst with completely isolated Ni sites to optimize acetylene semi‐hydrogenation processes. Such Ni sites show not only preferential acetylene π‐adsorption, but also enhanced ethylene desorption. The characteristics of the Ni sites are confirmed by multiple characterization techniques, including aberration‐corrected high‐resolution scanning transmission electron microscopy and X‐ray absorption spectrometry measurements. The superior performance is also confirmed experimentally against a Ni₅Ga₃ intermetallic catalyst with partially isolated Ni sites and against a Ni catalyst with multi‐atomic ensemble Ni sites. Accordingly, the NiGa intermetallic catalyst with the completely isolated Ni sites shows significantly enhanced selectivity to ethylene and suppressed coke formation.     

无绝缘高温超导双饼线圈的瞬态电热特性分析

无绝缘高温超导线圈具有良好的电热稳定性和机械紧凑性,但其充电过程中却有明显的磁场延迟现象。为详细了解无绝缘高温超导线圈励磁过程的瞬态特性,建立了无绝缘高温超导线圈的同轴圆环等效电路模型。通过绕制一个670匝的无绝缘高温超导双饼线圈,在液氮温度下进行不同充电速率的励磁实验,初步验证了等效电路模型的正确性。基于该模型,针对线圈励磁过程的充电和恒流阶段,仿真得到了线圈各匝的径向电流分布规律和电热损耗特性。     

Structure-tuned membrane active Ir-complexed oligoarginine overcomes cancer cell drug resistance and triggers immune responses in mice

The development of chemotherapy, an important cancer treatment modality, is hindered by the frequently found drug-resistance phenomenon. Meanwhile, researchers have been enthused lately by the synergistic use of chemotherapy with emerging immunotherapeutic treatments. In an effort to address both of the two unmet needs, reported herein is a study on a series of membrane active iridium(iii) complexed oligoarginine peptides with a new cell death mechanism capable of overcoming drug resistance as well as stimulating immunological responses. A systematic structure–activity relationship study elucidated the interdependent effects of three structural factors, i.e., hydrophobicity, topology and cationicity, on the regulation of the cytotoxicity of the Ir(iii)-oligoarginine peptides. With the most prominent toxicities, Ir-complexed octaarginines (R8) were found to display a progressive oncotic cell death featuring cell membrane-penetration and eruptive cytoplasmic content release. Consequently, this membrane-centric death mechanism showed promising potential in overcoming multiple chemical drug-resistance of cancer cells. More interestingly, the eruptive mode of cell death proved to be immunogenic by stimulating the dendritic cell maturation and inflammatory factor accumulation in mice tumours. Taking these mechanisms together, this work demonstrates that membrane active compounds may become the next generation chemotherapeutics because of their combined advantages.

Structure optimized Ir-complexed cyclic octa-arginine shows a potential of “one-drug two-effects” for cancer treatment.     

Bifurcations and dynamics of a plant disease system under non-smooth control strategy

Nonlinear Dynamics - Mathematical models and analyses can assist in designing the control strategies to prevent the spread of infectious disease. The present paper investigates the bifurcations and...     

考虑制动力影响的大型客车舒适性分析

利用有限元法和动力平衡原理,建立了具有层间接触的沥青路面和13个自由度的大型客车人体三维模型。以不平顺作为激励,随机模拟车流分布,在不同制动情况下,从时域和频域两方面分析人-车-路耦合振动下车辆和人体的动力响应。时域分析采用客观评价标准和主观烦恼率相结合的方法,频域分析考虑人体共振、人的心理和生理因素。结果表明:随着制动力增大,人体的竖向加速度幅值不变,俯仰、侧倾加速度幅值都增大,但是俯仰加速度增幅远大于侧倾加速度的情况,人的舒适性变差,烦恼率增高;在紧急制动时,主频段对人体共振、心理和生理产生的影响很小,但是次主频段与人体某些器官固有频段重合,对人体共振、心理和生理产生的影响是不容忽视的。     

高盐样品中锂的电感耦合等离子体发射光谱法(ICP-OES)测定研究

锂是重要的战略金属和新能源材料,其开发利用受到全球的高度关注。在高盐卤水特别是盐湖卤水和地下卤水中富含巨量的锂资源,在对这些资源进行锂的开发利用过程中,需对锂的含量进行准确测定,然而卤水中共存的高浓度Na+, K+, Ca2+和Mg2+会对微量锂的准确测定产生严重的干扰。电感耦合等离子体发射光谱法(ICP-OES)具有线性范围宽和多元素同步分析能力,针对卤水中锂的快速准确测定,详细开展了高盐样品中锂的ICP-OES分析方法研究。结果表明,锂在610.364 nm处具有较高的信噪比,且Na+, K+, Ca2+, Mg2+和Ar不会对锂的测定产生显著的谱线干扰。然而,样品中大量共存的Na+, K+和Mg2+会对锂的测定产生严重的基体正干扰,而Ca2+产生负干扰。尽管内标法在消除基体干扰方面具有广泛的应用,但传统的以钇和钪为内标元素的内标法不能有效解决该问题。此外,针对标准加入法操作繁琐、不适合批量样品分析问题,以及基体匹配法需多离子匹配,且不适合样品基体组成变化的批量样品分析等问题,考察了采用单一组分进行复杂基体匹配的可行性。由于NaCl广泛存在于卤水中,且对锂的测定具有显著的增敏效应,通过系列研究发现,通过同时向样品和标准溶液中加入10 g·L-1的NaCl,成功解决了总量不超过40 g·L-1的NaCl, KCl和MgCl2所产生的干扰。尽管采用该法或沉淀预分离方式均不能消除Ca2+产生的负干扰,但当样品中Ca2+含量不高于1.8 g·L-1时,对测定不产生显著的影响。通过采用该方法对三种不同基体组成的卤水样品进行加标回收测定,其回收率在96.60%~104.20%范围内。此外,通过与电感耦合等离子体质谱法(ICP-MS)测定结果进行对比,充分论证了该法的准确性和可靠性(相对误差±3.66%)。该法仅以单一的NaCl进行复杂基体匹配,不仅简化了操作,还实现了基体组成变化的批量样品分析,因而在卤水中锂的快速准确测定及锂资源开发利用方面具有重要意义。     

An improved evaluation of the neutron background in the PandaX-Ⅱ experiment

In dark matter direct detection experiments,neutron is a serious source of background,which can mimic the dark matter-nucleus scattering signals.In this paper,we present an improved evaluation of the neutron background in the PandaX-II dark matter experiment by a novel approach.Instead of fully relying on the Monte Carlo simulation,the overall neutron background is determined from the neutron-induced high energy signals in the data.In addition,the probability of producing a dark-matter-like background per neutron is evaluated with a complete Monte Carlo generator,where the correlated emission of neutron(s)andγ(s)in the(α,n)reactions and spontaneous fissions is taken into consideration.With this method,the neutron backgrounds in the Run 9(26-ton-day)and Run 10(28-ton-day)data sets of PandaX-II are estimated to be(0.66±0.24)and(0.47±0.25)events,respectively.