摘要：Thermodynamic simulation was conducted to design a new process of stepwise precipitating NH_(4)VO_(3)and NaHCO_(3)from regulating the CO_(2)carbonation of Na_(3)VO_(4)***,a new V(V)speciation model for the aqueous solution containing vanadate and carbonate is established by using the Bromley-Zemaitis activity coefficient ***,thermodynamic equilibrium calculations are conducted to clarify the behavior of vanadium,carbon,sodium,and impurity species in atmospheric or high-pressure *** ensure the purity and recovery of vanadium products,Na_(3)VO_(4)solution is initially carbonated to the pH of 9.3-9.4,followed by precipitating NH_(4)VO_(3)by adding(NH_(4))_(2)CO_(3).After vanadium precipitation,the solution is deeply carbonated to the final pH of 7.3-7.5 to precipitate NaHCO_(3),and the remaining solution is recycled to dissolve Na_(3)VO_(4)***,verification experiments demonstrate that 99.1%of vanadium and 91.4%of sodium in the solution are recovered in the form of NH_(4)VO_(3)and NaHCO_(3),respectively.

摘要：3 m多长的伸杆机构是天问一号火星磁强计的一个重要组成部分,用于将磁通门磁强计探头伸离卫星本体以减小卫星对磁场测量的影响。火星磁强计伸杆机构是一种多关节、铰链转轴驱动的一次性展开机构。在设计时充分考虑到了其功能性、可靠性和系统约束要求等因素。力学分析和地面验证试验表明火星磁强计伸杆机构足以承受最坏情况下的在轨环境。在经历了漫长的地火转移旅程后,火星磁强计伸杆机构于2021年5月25日成功展开。展开过程耗时约4.6 s,两个探头被送至远离环绕器本体位置,其中外侧探头距离环绕器3.19 m,内侧探头距离环绕器2.29 m。展开到位后,外侧探头处所测得的磁场大小由1250 nT减弱至不到6 nT。火星磁强计伸杆机构为后续探测任务中需在低温环境下长期贮存的空间展开机构的研制提供了宝贵的工程经验。

摘要：Dear Editor,Myocardial infarction(MI)is the irreversible cardiomyocyte death resulting from prolonged oxygen deprivation due to obstructed blood supply(ischemia),leading to contractile dysfunction and cardiac *** recent decades,stem cell transplantation has been extensively investigated for the repair of injured heart in animal studies and clinical trials(Kanelidis et al.,2017;Gyongyosi et al.,2018).

摘要：Pt/Au/WO_3 bimetallic catalysts were prepared by impregnation of Pt onto preformed Au/WO_3,obtained by a hexadecyl trmethyl ammonium bromide（CTAB）-assisted one-pot synthesis *** resulting Pt/Au/WO_3 catalysts exhibited remarkable synergistic effects for selective hydrogenolysis of glycerol to 1,3-propanediol. The characterization results showed that doping of Au promoted the reduction of both Pt and W at low temperatures and uniform dispersion of Pt on the WO_3 support. Furthermore, more low-valence Pt species were produced on the WO_3 surface after introduction of Au. These changes in electronic properties resulted in enhancement of both glycerol conversion and selectivity for 1,3-propanediol.

摘要：非质子锂氧电池基于锂金属与氧的可逆反应生成Li_(2)O_(2),可提供极高的理论能量密度.然而,Li_(2)O_(2)的成核/消除机制仍然不清楚.因此,构建能在原子水平上深入了解催化机理的催化剂体系,是开发高性能锂氧电池的关键.在此,我们报道了一种在富氧空位的Co_(3)O_(4)(Pd1-Co_(3)O_(4x))中实现Pd单原子选择性锚定的策略.原子水平表征技术揭示了Pd原子优先地结合到缺陷Co_(3)O_(4)的四面体位点.理论计算表明,选择性锚定的Pd单原子与氧空位的耦合引起了明显的电荷重分布,这可以有效地提高Pd 4d轨道在费米能级附近的能带占用率,促进电子转移,有利于中间体的吸附.这种双重相互作用不仅可以调节放电过程中Li_(2)O_(2)的成核生长过程,而且有利于Li_(2)O_(2)上的电子云的离域,减弱Li-O键的强度,从而促进Li_(2)O_(2)在充电过程中的分解.本研究对锂氧电池在原子水平上的催化机理和高效催化剂的合理设计提出了一些见解.

摘要：设计并搭建了一个新的双反应器烟雾箱,用于研究可生成臭氧或二次有机气溶胶(SOAs)的大气氧化过程.该烟雾箱包括一个绝热的箱体及其内部两个体积为5 m3的氟化乙丙烯(FEP)薄膜反应器,箱内的温度可以精确控制在-10到40°C之间.利用该烟雾箱研究了光源对丙烯气相氧化机理的影响,发现相对于传统的黑光灯光源,采用的多重光源所得到的结果可以与模型更好地匹配.进行了丙烯和间二甲苯的光氧化的初步实验,发现该烟雾箱可用于模拟可产生臭氧或SOAs的气相氧化过程,并可以通过不同初始浓度的对比实验找寻不同物种对反应过程的影响.间二甲苯在不同NOx条件下光氧化得到的SOA产率与之前的研究比较符合,这表明该烟雾箱可以实现气-粒转化过程的模拟.双反应器可以实现在一个关键条件的存在区别,而其他条件完全一致的情况下的对比实验,从而帮助我们进一步理解在大气复合污染过程中起关键作用的因素.

摘要：Atrial fibrillation is an “invisible killer” of human health. It often induces high-risk diseases, such as myocardial infarction, stroke, and heart failure. Fortunately, atrial fibrillation can be diagnosed and treated early. Low-level vagus nerve stimulation(LL-VNS) is a promising therapeutic method for atrial fibrillation. However, some fundamental challenges still need to be overcome in terms of flexibility,miniaturization, and long-term service of bioelectric stimulation devices. Here, we designed a closedloop self-powered LL-VNS system that can monitor the patient’s pulse wave status in real time and conduct stimulation impulses automatically during the development of atrial fibrillation. The implant is a hybrid nanogenerator(H-NG), which is flexible, light weight, and simple, even without electronic circuits,components, and batteries. The maximum output of the H-NG was 14.8 V and 17.8 μA(peak to peak). In the in vivo effect verification study, the atrial fibrillation duration significantly decreased by 90% after LLVNS therapy, and myocardial fibrosis and atrial connexin levels were effectively improved. Notably, the anti-inflammatory effect triggered by mediating the NF-κB and AP-1 pathways in our therapeutic system is observed. Overall, this implantable bioelectronic device is expected to be used for self-powerability,intelligentization, portability for management, and therapy of chronic diseases.

摘要：The high cost and low efficiency of fatigue tests are bottleneck problem for the anti-fatigue design of metallic *** this problem,a theoretical fatigue model is proposed in this study,the possible applications have also been *** results would be introduced in two serial papers,in which the first paper focuses on the model building and the applications on fatigue strength prediction;the second paper put emphasis on the influencing factors of the model parameters and the applications on fatigue strength *** this first paper,a theoretical model is proposed considering both the strength and plastic restrictions of fatigue *** the model builds up a brief relationship among yield strength(Y),tensile strength(T)and fatigue strength(F),it is named as the Y-T-F *** the verification with fatigue strength data covering various kinds of metallic materials and loading conditions,this Y-T-F model exhibits both generality and *** the Y-T-F model,the efficient fatigue strength prediction could be conducted by brief linear fitting and calculation,just through yield strength,tensile strength and several known fatigue strength ***,through its deduced Y-F model,the analytical formula of fatigue strength continuously changing with materials strengthening can be obtained,as well as the maximum value of fatigue strength and corresponding critical yield *** summary,the Y-T-F model would be useful for reducing the fatigue tests,thus providing new possibilities on the efficient anti-fatigue design and selection of metallic materials.

摘要：In this paper, we propose a new lightweight block cipher named RECTANGLE. The main idea of the design of RECTANGLE is to allow lightweight and fast implementations using bit-slice techniques. RECTANGLE uses an SP-network. The substitution layer consists of 16 4 × 4 S-boxes in parallel. The permutation layer is composed of 3 rotations. As shown in this paper, RECTANGLE offers great performance in both hardware and software environment, which provides enough flexibility for different application scenario. The following are3 main advantages of RECTANGLE. First, RECTANGLE is extremely hardware-friendly. For the 80-bit key version, a one-cycle-per-round parallel implementation only needs 1600 gates for a throughput of 246 Kbits/s at100 k Hz clock and an energy efficiency of 3.0 p J/bit. Second, RECTANGLE achieves a very competitive software speed among the existing lightweight block ciphers due to its bit-slice style. Using 128-bit SSE instructions,a bit-slice implementation of RECTANGLE reaches an average encryption speed of about 3.9 cycles/byte for messages around 3000 bytes. Last but not least, we propose new design criteria for the RECTANGLE *** to our careful selection of the S-box and the asymmetric design of the permutation layer, RECTANGLE achieves a very good security-performance tradeoff. Our extensive and deep security analysis shows that the highest number of rounds that we can attack, is 18(out of 25).

摘要：研究了一种新型优化算法。利用 Boltzm ann机人工神经网络的理论和方法 ,结合模拟退火算法 ,构造合适的求解优化设计问题的人工神经网络 ,将优化问题的寻优过程和 Boltzm ann机的演化过程进行对应 ,将优化问题的目标函数和 Boltzmann机的能量函数相对应。以铰链四杆机构实现给定运动规律为仿真实例 ,进行了验证。