Interior regularity of optimal transport paths

In a previous paper [12], we considered problems for which the cost of transporting one probability measure to another is given by a transport path rather than a transport map. In this model overlapping transport is frequently more economical. In the present article we study the interior regularity properties of such optimal transport paths. We prove that an optimal transport path of finite cost is rectifiable and simply a finite union of line segments near each interior point of the path.Received: 30 October 2002, Accepted: 26 August 2003, Published online: 15 October 2003Mathematics Subject Classification (2000): 90B06, 49Q20.     

Accumulation and toxic effect of organometallic compounds on algae

This paper reports toxic effects and bioaccumulation factors of organometallic compounds, mainly organotin species, on algae. We selected two species of microalgae as test algae: one was Scenedesmus obliquus as a representative of fresh-water algae, the other Dunaliella salina and Dunaliella viridis, to represent commonly mixed algae which exist abundantly in Tianjin Harbor, People's Republic of China. For comparison, Chlorella vulgaris was also used in this study. The toxic effect of ten organometallic compounds on the freshwater alga, S. obliquus, was investigated. The ten compounds were (as chlorides) tributyltin (TBT); triphenyltin (TPT); trimethyltin (TMT); dibutyltin (DBT); diphenyltin (DPT); dimethyltin (DMT); trimethyl-lead acetate (TML); dimethyl-arsine (DMA) and two new mixed-alkyltin pesticides, dicyclohexylmethylitin acetate (Cy₂MTA) and dicyclohexylmethyltin isobutyrate (Cy₂MTB). The order of toxicity of these compounds in fresh-water algae, S. obliquus, was TBT>TPT>DBT> Cy₂MTA=TML> Cy₂MTB>DPT>TMT>DMA>DMT, according to 96 h EC₅₀ values attained. The ten toxicants were divided into three groups according to the sequence of their toxicities; (a) TBT, TPT; (b) DBT, Cy₂MTA, TML, Cy₂MTB; (c) DPT, TMT, DMA, DMT. In each group the EC₅₀ values of each compound were quite similar. The difference of EC₅₀ values between two vicinal groups was approximately one order of magnitude. The bioconcentration factor (BCF) of TBT and TPT compared with water in the freshwater alga S. obliquus was >3.32 × 10⁵ and 1.14 × 10⁵, respectively. The BCF of the marine mixed algae was >3.48 × 10⁵. The marine microalga, Chlorella vulgaris, was adaptable to TBT at lower concentration. TBT at high concentration only inhibited the growth of S. obliquus, but it could cause chlorosis anddisintegration of D. salina and D. viridis. Resistance to toxicity of algae against TBT appears in order as follows: C. vulgaris>S. obliquus>D. salina and D. viridis. TBT was metabolized by algae to a less toxic product, DBT. The existence of algal cells accelerated the concentration reduction of TBT. The toxic mechanism of TBT was also studied.     

1-酰氧基-2,8,9-三氧杂-5-氮杂-1-锗杂三环[3,3,3,O~(1,5)]十-碳烷的合成和结构研究

1-氯代杂氮锗三环与羧酸钾盐反应生成1-酰氧基杂氮锗三环化合物。通过IR，1HNMR和质谱确定了它们的结构。测定了化合物SCH＝CHCHC－COOGe（OCH2CH2）3N的晶体结构，化合物为五配位，N→Ge键长为0．212nm。     

Activation pressure studies with an iron-based catalyst for slurry Fischer-Tropsch synthesis

Fischer-Tropsch synthesis (FTS) was carried out with an industrial iron-based catalyst (100Fe/5Cu/6K/16SiO2, by weight) under the baseline conditions in a stirred tank slurry reactor (STSR). The effects of activation pressure on the catalyst activity and selectivity were investigated. It was found that iron phase compositions, textural properties, and FTS performances of the catalysts were strongly dependent on activation pressure. The high activation pressure retards the carburization. Møssbauer effect spectroscopy (MES) results indicated that the contents of the iron carbides clearly decrease with the increase of activation pressure, especially for the activation pressure increasing from 1.0 MPa to 1.5 MPa, and the reverse trend is observed for superparamagnetic Fe3+ (spm). The higher content of Fe3+ (spm) results in the higher amount of CO2 in tail gas when the catalyst is reduced at higher pressure. The catalyst activity decreases with the increase of activation pressure. The high quantity of iron carbides is necessary to obtain high FTS activity. However, the activity of the catalyst activated in syngas can not be predicted solely from the fraction of the carbides. It is concluded that activation with syngas at the lower pressure would be the most desirable for the better activity and stability on the iron-based catalyst.     

混合三烃基锡衍生物的研究Ⅹ．甲基二环己基锡二硫代磷酸酯的合成及生物活性

合成了10种甲基二环己基锡-O,O-二烃基二硫代酸酸酯.利用IR、NMR,MS及元素分析确证了化合物的结构,生物活性测试结果表明,这类化合物具有较高的杀螨和除草活性.     

Synthesis,structures and in vitro anticancer activity of some germanium-substituted di-n-butyltin dipropionates

Organotin and organogermanium compounds are extensively studied for their wide range of biological activity. To link biological active properties of organotin and organogermanium, sixteen new germanium-substituted di-n-butyltin dipropionates with the form (R₃GeCHR¹CHR²COO)₂SnBu₂ⁿ·H₂O were synthesized.     

饱和食盐水比热容测量的不确定度

用一种简易的控温方法实现对饱和食盐水比热容的散热法测量,并对其结果的不确定度进行分析.与文献值比较,该方法所得结果可信,其不确定度主要来源于系统的散热系数及温度的测量.     

环境干预对提高手术满意度的探讨

目的探讨基层医院手术室通过开展优质护理,从而缩短手术时间,提高工作质量,有效地减轻手术患者术前、术中、术后的恐惧心理。方法通过对540例手术患者的需求进行调查分析,制定并实施了人性化的"优质温馨手术服务"。结果 "优质温馨手术服务"实施后,手术室全年综合满意度达到99%。结论 "优质温馨手术服务"密切了护患关系,缩短了手术时间,有效减轻了患者的恐惧,提高了护理质量和患者及家属的满意度。     

1,3-Di­chloro-1,1-di­methyl-3,3-diiso­propyl­distannoxane

The title compound, [Sn₄(CH₃)₄(C₃H₇)₄Cl₄O₂] or {Cl[(CH₃)₂CH]₂SnOSn(CH₃)₂Cl}₂, obtained by the reaction of [(CH₃)₂CH]₂SnO and (CH₃)₂SnCl₂, exists as centrosymmetric dimers in the solid state. It contains a central planar four-membered Sn₂O₂ ring. The coordinate geometry about the Sn atoms is distorted trigonal pyramidal.     

Analysis of the dynamics of Cournot team-game with heterogeneous players

In this paper, we study a dynamical system of a two-team Cournot game played by a team consisting of two firms with bounded rationality and a team consisting of one firm with naive expectation. The equilibrium solutions and the conditions of their locally asymptotic stability are studied. It is demonstrated that, as some parameters in the model are varied, the stability of the equilibrium will get lost and many such complex behaviors as the period bifurcation, chaotic phenomenon, periodic windows, strange attractor and unpredictable trajectories will occur. The great influence of the model parameters on the speed of convergence to the equilibrium is also shown with numerical analysis.