Maximum work configurations of finite potential capacity reservoir chemical engines

An isothermal endoreversible chemical engine operating between the finite potential capacity high-chemical-potential reservoir and the infinite potential capacity low-chemical-potential reservoir has been studied in this work.Optimal control theory was applied to determine the optimal cycle configurations corresponding to the maximum work output per cycle for the fixed total cycle time and a universal mass transfer law.Analyses of special examples showed that the optimal cycle configuration with the mass tr...     

悬浮体进样石墨炉原子吸收光谱法直接测定煤中微量砷

以Pd为基体改进剂 ,建立了浮体制样石墨炉原子吸收光谱法直接测定煤中微量As的方法。研究了悬浮体的稳定性、试样粒度、基体改进剂、灰化温度、原子化温度和常见共存离子等因素对待测物信号强度的影响。在优化实验条件下 ,方法的检出限为 0 0 5 4 μg·g-1,相对标准偏差 (RSD)为 8 9%     

Exposure to persistent organic pollutants as potential risk factors for developing diabetes

Persistent organic pollutants(POPs),such as dioxins,polychlorinated biphenyls(PCBs) ,and organochlorine pesticides(OCPs),which are synthetic chemicals or by-products with an intrinsic resistance to natural degradation processes,are released into the environment,resulting in the widespread dispersal and accumulation in the environment,as well as in human and ecological food chains.Due to their ubiquity in the environment and lipophilic properties,there is emerging concern over the potential risks of human ex...     

有限势库化学机最大输出功时循环最优构型

基于有限势容高化学势库和无限势容低化学势库间工作的等温内可逆化学机,在循环总时间一定的条件下,应用最优控制理论导出了一类普适传质规律下对应于最大输出功时化学机循环最优构型.特例分析表明传质定律为g∝△μ(△μ为化学势差)时循环最优构型为低化学势侧工质中关键组分的化学势(或浓度)为常数,而工质与有限势容高化学势库间关键组分的化学势(或浓度)均随时间呈非线性变化且化学势之差(浓度之比)为常数的等温内可逆化学机循环;传质定律为g∝△c(△c为浓度差)时循环最优构型与传质定律g∝△μ下循环最优构型存在显著不同;当高化学势库也为无限势容化学势库时,循环最优构型由两个等化学势传质分支和两个等质量流率分支组成,且与具体的传质定律无关.本文的研究对象具有一定的普适性,研究结果对于实际化学机的优化设计与最优运行具有一定参考价值.     

ADMISSIBILITY IN THE GENERAL GROWTH CURVE MODEL WITH RESPECT TO RESTRICTED PARAMETER SETS UNDER MATRIX LOSS FUNCTION

In this paper, we study the issue of admissibility in the growth curve model with respect to restricted parameter sets under matrix loss function. We obtain some neces- sary and sufficient conditions that the linear estimators of KBL are admissible in the class of homogeneous linear estimators and in the class of non-homogeneous linear estimators under the growth curve model with respect to restricted parameter sets, respectively.     

INEQUALITIES OF EIGENVALUES FOR BI-KOHN LAPLACIAN ON HEISENBERG GROUP

In this article, we consider the eigenvalue problem for the bi-Kohn Laplacian and obtain universal bounds on the （k ＋ 1）-th eigenvalue in terms of the first k eigenvalues independent of the domains.     

Weak Orlicz space and its applications to the martingale theory

In this paper,the weak Orlicz space wL Φ is introduced and its applications to the martingale theory are discussed.In particular,a series of martingale inequalities including the maximal function inequality in weak Orlicz spaces are established;the relationships between these spaces are investigated.Moreover,the boundedness of several sublinear operators from one weak Orlicz space to another is proved;their vector-valued analogues are also considered.     

Conformal isoparametric hypersurfaces with two distinct conformal principal curvatures in conformal space

The conformal geometry of regular hypersurfaces in the conformal space is studied.We classify all the conformal isoparametric hypersurfaces with two distinct conformal principal curvatures in the conformal space up to conformal equivalence.     

百瓦级全固态绿光激光器的实验研究

利用80个20 W的二极管呈五角型阵列泵浦Nd:YAG棒,采用KTP晶体（Ⅱ类相位匹配θ＝90°,φ＝23.6°）腔内倍频、单声光调Q装置、平凹直腔结构,在泵浦电流17.5A、声光调制频率20.4kHz 时获得了平均输出功率为97 W、脉冲宽度150 ns的准连续绿光;分析了泵浦功率密度及晶体内部温度是影响倍频效率的因素,认为此实验中获得高功率的关键原因是对KTP晶体使用了角度调节并加强了水冷.     

Quasi-variational principles of single flexible body dynamics and their applications

The reasons for studying single flexible body dynamics are that on one hand, it is the basis of flexible multi-body dynamics. If the theory of the single flexible body dynamics has been deeply studied, the theory of flexible multi-body dynamics will be researched easily. On the other hand, it has its unique and important applications. Quasi-variational principle of non-conservative single flexible body dynamics is established under the cross-link of particle rigid body mechanics and deformable body mechanics. Taking the interceptor as an example, this paper has explained the physical meaning of the quasi-stationary value condition of the quasi-variational principle in non-conservative single flexible body dynamics. Taking the launch of rocket as an example, it has illustrated the features of “one force for two effects” in a single flexible body dynamics. With an example of the extending flexible beam coupled with the spacecraft attitude, it has shown the transition from the single flexible body dynamics to the flexible multi-body dynamics. Finally, a number of related problems are discussed. Supported by the National Natural Science Foundation of China (Grant No. 10272034), the Doctoral Education Foundation (Grant No. 20060217020), and the Natural Science Foundation of Harbin Engineering University (Grant No. HEUF04003)