Magnetization Reversal in CsNiIICrIII(CN)6 Coordination Nanoparticles: Unravelling Surface Anisotropy and Dipolar Interaction Effects

CsNiCr(CN)₆ coordination nanoparticles with sizes ranging from 6 to 30 nm are highly diluted in an organic polymer matrix. Their static and dynamic magnetic behaviour allows unravelling of surface anisotropy and interparticle dipolar interaction effects. The single magnetic domain critical size is thus evaluated to be around 22 nm with a blocking temperature of 21 K (at ν = 1 Hz) and an effective energy barrier for the reversal of the magnetization of 426 K.     

如何实现真实世界下的PC“绿色”能效

计算机原设备制造商（OEM）正面对商业、环保和法规等多方面的压力,需要体现他们产品的能效,提供更“绿色”的台式个人电脑（PC）和服务器。这使设计这些产品的工程师需要设计出符合诸如美国80 PLUS、“能源之星”（ENERGYSTAR）和计算产业拯救气候行动计划（CSCI）等能效标准的PC电源。     

The Zintl Compound Ca5Al2Sb6 for Low‐Cost Thermoelectric Power Generation

Understanding transport in Zintl compounds is important due to their unusual chemistry, structural complexity, and potential for good thermoelectric performance. Resistivity measurements indicate that undoped Ca₅Al₂Sb₆ is a charge‐balanced semiconductor with a bandgap of 0.5 eV, consistent with Zintl–Klemm charge counting rules. Substituting divalent calcium with monovalent sodium leads to the formation of free holes, and a transition from insulating to metallic electronic behavior is observed. Seebeck measurements yield a hole mass of ～2m_e, consistent with a structure containing both ionic and covalent bonding. The structural complexity of Zintl compounds is implicated in their unusually low thermal conductivity values. Indeed, Ca₅Al₂Sb₆ possesses an extremely low lattice thermal conductivity (0.6 W mK^?1 at 850 K), which approaches the minimum thermal conductivity limit at high temperature. A single parabolic band model is developed and predicts that Ca_4.75Na_0.25Al₂Sb₆ possesses a near‐optimal carrier concentration for thermoelectric power generation. A maximum zT > 0.6 is obtained at 1000 K.Beyond thermoelectric applications, the semiconductor Ca₅Al₂Sb₆ possesses a 1D covalent structure which should be amenable to interesting magnetic interactions when appropriately doped.     

Codelivery of NOD2 and TLR9 Ligands via Nanoengineered Protein Antigen Particles for Improving and Tuning Immune Responses

Vaccine adjuvants that can induce robust protective immunity are highly sought after for the development of safer and more effective vaccines. Vaccine formulation parameters that govern efficacy are still far from clear, such as the diverse impacts of codelivering agonist molecules for innate cell receptors (e.g., pattern recognition receptors). In this study, a mesoporous silica‐templating approach is used to fabricate protein antigen (ovalbumin) particles covalently functionalized with agonists for NOD‐like receptor 2 (NOD2) and Toll‐like receptor 9 (TLR9). Particle‐induced combinatorial NOD2/TLR9 signaling results in synergistic inflammatory cytokine secretion by mouse macrophages (RAW 264.7). Administration of NOD2/TLR9 particles in mice results in adaptive immune responses that are both quantitatively and qualitatively different than those resulting from administration of particles conjugated with either NOD2 or TLR9 agonists alone. While delivery of NOD2 agonists alone activates T helper 2 (Th2)‐type responses (and no CD8+ T cell activation) and delivery of TLR9 agonists alone activates CD8+ T cell and T helper 1 (Th1)‐type responses, codelivery of NOD2 and TLR9 agonists enhances Th1‐type responses and abrogates CD8+ T cell activation. The results illustrate that in the particle‐based system, NOD2 activation plays different roles in polarizing adaptive immune responses depending on coactivation of TLR9.     

开关电容ADC及其驱动放大器之间的阻抗谐振匹配方法

高采样速率模数转换器（ADC）通常用在现代无线接收器设计中,以中频（IF）采样速率采集复数调制的信号.这类设计通常都选用基于CMOS开关电容的ADC,因为它们的低成本和低功耗特点很吸引人。但这类ADC采用一种直接连接到采样网络的无缓冲器的前端,这样就会出现驱动ADC的放大器的输入跟踪和保持阻抗随时间变化的问题.为了有效地驱动ADC,使噪声最低和有用信号失真最小,必须设计一种无源网络接口帮助抑制宽带噪声,并对跟踪阻抗和保持阻抗进行变换以便为驱动放大器提供更好的负载阻抗。针对几种常见的IF频率,本文中提出了一种谐振匹配方法,用于将跟踪和保持阻抗转换为比较容易计算的负载,从而实现抗锯齿滤波器的精密设计。     

Alcohol-induced changes of {beta}-lactoglobulin - retinol-binding stoichiometry

It has been demonstrated using CD that ethanol induces importantsecondary structure changes of ß-lactoglobulin. CDspectra indicate that ß-lactoglobulin secondary structure,which is mainly composed of ß-strands, becomes mostly-helical under the influence of the solvent polarity changes.The midpoint of ß-strand/-helix transition in ß-lactoglobulinis observed at dielectric constant {small tilde}60 (35% ethanol;v/v). According to CD measurements, the ethanol-dependent secondarystructure changes are reversible. The alkylation of lysines-NH₂ in ß-lactoglobulin weakens the central ß-barrelstructure, since the ß-strand/-helix transition midpointof alkylated ß-lactoglobulin is shifted to lower ethanolconcentration (25% ethanol; v/v). ß-Lactoglobulinstructural changes are triggering the dissociation of the ß-lactoglobulin- retinol complex as judged from complete quenching of its fluorescencein ethanol concentration >30% (v/v). However, in 20% ethanol(v/v), ß-lactoglobulin still retains most of its nativesecondary structure as shown by CD and, in this condition, oneß-lactoglobulin molecule binds an additional secondretinol molecule. This suggests that the highly populated speciesobserved around 20% ethanol (v/v) might represent an intermediatestate able to bind two molecules of retinol.     

Thermodynamic Theory of Single-Crystal Lead Titanate with Consideration of Elastic Boundary Conditions

A phenomenological free-energy function including the effects of elastic boundary conditions was presented and used to investigate the single-domain, single-crystal properties of the ferroelectric perovskite, PbTiO₃. In particular, the effects of tensile and compressive hydrostatic stress on the spontaneous polarization, Curie point, dielectric susceptibility, and piezoelectric property coefficients were examined. The calculated shift of the Curie point with hydrostatic stress, along with the entropy and enthalpy of the ferroelectric-paraelectric phase transition, was found to be in good agreement with experimental measurements. The isothermal variation of the relative dielectric susceptibility and piezoelectric coefficients with hydrostatic stress exhibited the expected behavior near the ferroelectric-paraelectric phase transition.     

Ultrasonic Dispersion of Ceramic Powders

Ultrasonication is very effective in dispersing alumina and barium titanate slurries. When optimum conditions are used, very short durations (2 to 3 min) are enough to achieve well-dispersed, stable suspensions.     

用于制导弹药的自适应自动驾驶仪设计

传统制导弹药自动驾驶仪的设计要求精确的气动模型,并依赖于变增益(gainschedule),以说明系统的非线性.本文给出了一种简化自动驾驶仪设计程序的方法:在单一飞行条件下设计逆控制器,将逆控制器与在线神经网络组合,以说明因近似逆引起的误差,这样减少了大量设计程序及精确的气动数据.这些数据在大攻角或其它情况下很重要,因为这些领域中的空气动力特征变得高度非线性化.研究发现:逆的选择在其实现的过程中很重要,所以详细讨论.最后,给出该方法在非线性6自由度制导弹药中的模拟结果.     

Heuristic circuit simulation using PROLOG

Through the use of the logic programming language PROLOG, digital logic circuitry can be conveniently represented in predicate calculus in a manner amenable to various forms of computation. Axioms define the behavior of primitive gates in a given technology, and implications hierarchically characterize the behavior of non-primitive modules.Simulation of circuitry proceeds by theorem proving, viewed as constraint satisfaction. A PROLOG-based simulator is presented for the investigation of heuristics to efficiently solve problems of ‘backward’ simulation which arise in a number of areas, such as reasoning about fault isolation. The heuristic simulator can also serve as the basis for an elegant implementation of Roth's D-algorithm.