The Intersection of Opposed Big Cells in The Real Flag Variety of Type G2

We compute the Euler characteristics of the individual connectedcomponents of the intersection of two opposed big cells in thereal flag variety of type G₂, verifying a conjecture of Rietsch[6]. 2000 Mathematical Subject Classification: primary 14M15; secondary20G20.     

The problem of the relation between double pomeron exchange in inclusive and exclusive experiments

The pionization region of the inclusive single-particle spectrum is accounted for by double pomeron exchange in the absorptive part of a six-point amplitude. In this paper a multiperipheral model for the six-point amplitude with double pomeron exchange is used for continuation by crossing and analyticity to the physical region of the exclusive two particle → four particle production process. The cross section for π^? p → π^?(π⁺π^?)p in the double-Regge region is then calculated and compared with the experimental analysis of Lipes, Zweig and Robertson which sets an upper bound to the strength of the double pomeron exchange coupling. This upper bound, coupled with the model for continuation to the inclusive cross section, is shown to give too small a magnitude for the double pomeron exchange in the pionization region. Further avenues for investigation are discussed.     

Search for charmed hadrons in neutral strange particle events in pp interactions at 19 GeV/c

A search for charmed hadrons has been made in proton-proton interactions at 19 GeV/c using events with one or two observed neutral strange particles. No evidence for charmed particles has been found. Upper limits for their production cross sections are presented.     

Effects of multiple blade interaction on the containment of blade fragments during a rotor failure

A finite element analysis is used to study the impact and the containment aspects of rotor blade fragments that are produced during a aircraft jet engine rotor failure. The impact and containment studies are performed on a ring-type containment structure and various fragment types are considered in this study. For each type of fragment, the ring thickness is varied incrementally and the ring response, residual kinetic energy level of the fragments, magnitude of impact forces and the overall containment or failure are determined. First, only a single fragment is considered and the rotor is assumed to contain no other blades. Next, the remaining blades are introduced and the effects of multiple collisions with the other blades on the containment are analyzed. The explicit, nonlinear finite element code Dyna3d is used for the numerical computations in this study and the results are compared with the experimental results performed on a T58 rotor at the spin facility of the Naval Air Propulsion Test Center.     

Determination of the regime in the reverse wilson chamber at critical supersaturation measurements

The pressure in the Reverse Wilson Chamber (RWC) was directly measured at different rates of compression of the gas mixture. It was shown that at compression time in the range from 0.06 to 0.3 s an intermediate, between adiabatic and isothermal, process took place in the chamber. To obtain the relative pressure increase P _m /P _at from the values of the relative gas compression V/V, a calibration of the experimental set-up was carried out. The calibration showed that the values of critical supersaturationSc for water condensation on hexadecane, estimated for intermediate regime of the gas compression, were reduced with respect to the values calculated when the adiabatic regime was assumed. This fact confirmed the conclusions made earlier [1–3] that the classical theory was not applicable in this case of heterogeneous phase formation and that the line tension < 0 should be taken into account. Moreover, in an atmosphere of very pure argon (instead of room air [1–3]) the critical supersaturation turned out to be independent of the initial state of undersaturationS _o . The more accurate values obtained for condensation of water on hexadecane were: lnS _c =0.204 (instead of the maximum value obtained earlier: lnS _c =0.26) and=–1.9×10^–5 dyne (instead of=–1.5×10^–5 dyne).     

广东星海音乐厅室内乐厅的声学设计

室内乐厅是以演奏室内乐为主、兼供独奏(唱)、音乐讲座、文娱演出和立体电影所用的多功能厅堂。为使各项功能均具有最佳的声学条件,设置了用计算机调控混响时间的装置。本文概要介绍室内乐厅的声学设计、但侧重于计算机调控混响时间所取得的成效。     

Search for exotic meson and hyperon final states in K-d interactions at 5.5 Gev/c

A search has been made for exotic states produced in K^?d interactions at 5.5 GeV/c. The reactions investigated were: K^?d→X^??pp, $\text{K}{}^{\mathrm{?}}\text{d}\text{→}\text{Y}{}^{\mathrm{1??}}\text{π}{}^{\mathrm{+}}\text{p}$ and K^?d→ M^??Σ⁺p. Upper limits are set for the production cross sections.     

电子电气产品中挥发性有机化合物的释放量测定

采用小型释放舱-热脱附-气相色谱-质谱联用技术测定了电子电气产品中8种挥发性有机化合物（苯、甲苯、邻二甲苯、间二甲苯、对二甲苯、乙苯、乙酸丁酯和苯乙烯）的释放量.对一级脱附参数（一级脱附温度、一级脱附流量、一级脱附时间）、冷阱温度、捕集管脱附温度、脱附时间条件进行了优化,并进行了线性关系、回收率、精密度等试验.结果表明：本方法可用于测定电子电气产品中释放的8种常见的挥发性有机化合物的释放量,线性范围10-1000ng,当采样量为6L时,定量限为1.7μg/m3,回收率范围在89.5％-106％之间,相对标准偏差小于7％.     

无银催化-密封恒温光度法快速测定化学需氧量

通过正交试验确定了密封恒温分光光度法测定化学需氧量的最佳条件：催化剂MnSO4—CuSO4配比为1：2，消解温度为165℃，消解时间为10min，消解用的H2SO4酸度为12mol／L等。本法测定的CODcr值与标准回流法所得结果一致。该法具有分析成本低，速度快的特点。