Characteristic scales of two‐dimensional turbulence in polymer solutions

An experimental study has been performed to investigate the relationship between the extensional viscosity of polymers and the turbulent drag reduction. Self‐standing flowing soap film was used to generate two‐dimensional (2‐D) turbulent flow to eliminate shear stress. Two types of polymers having different flexibilities were added to the 2‐D turbulence. The effects of these polymers were visualized by the interference pattern of flowing soap films. The vortex deformation by adding polymers was analyzed by Fourier transformation and wavelet transformation. The scaling exponents of the power spectrum of interference patterns indicate that the mechanism of turbulence laminarization due to the extensional viscosity is anisotropic. A wavelet analysis reveals the high and low fluctuations of the polymer‐added flow. Results from wavelet analysis indicate disappearing of original vortices, and appearing of new structures in low frequency in 2‐D flow. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1854–1862, 2014     

A hypopituitary patient who attained tall stature without growth hormone

In this report, incidence and clinical characteristics of Kaposi's sarcoma (KS) were retrospectively analyzed among renal transplant recipients who were being followed-up in the outpatient clinic of the Istanbul School of Medicine. Between October 1983 and December 1997, 17 cases of KS were diagnosed among 557 patients (3%). Of the total 25 post-transplant malignancies, KS was the most common tumor, representing a rate of 68%. Diagnosis was suspected with typical skin lesions and was confirmed by biopsy. Gastroduodenal endoscopy was applied to 7 patients in order to assess gastrointestinal tract involvement. Of the total number of patients diagnosed with KS 14 were male and 3 female, with the mean age of 40 +/- 15 (range 13-68) yr. The mean duration between the date of transplantation and diagnosis of KS was 15.9 +/- 20.3 (range 1-65) months. The lesions were limited to the skin in 13 patients, while skin and gastrointestinal tract were involved in 2 patients and generalized disease was noted in 2 patients. The initial therapeutic approach was to withdraw cyclosporine and to reduce azathioprine. In the case of progression of the lesions azathioprine was also stopped. Besides, surgical excision of the lesions, radiotherapy and/or chemotherapy were performed according to the clinical picture. Remission was observed in 14 patients after this therapy protocol. The 2 patients with gastrointestinal involvement and 1 patient with generalized KS died in spite of the above-mentioned therapeutic interventions. One of the patients on remission died of pneumonia. It was concluded that KS carried a high risk of morbidity and mortality in renal transplant recipients, and tapering of immunosuppression, especially withdrawal of cyclosporine, affected the prognosis favorably.     

以喷淋方式考察抗氧化护铜剂(OSP)的处理方法

近年来,"抗氧化护铜剂(又名有机预焊剂,水溶性耐热前处理型助焊剂,以下称OSP)"很广泛地应用于印制线路板的最终表面处理。一方面,印制线路板正急速地朝向小型化,高密度化发展,且已出现了焊盘最表面的阻焊膜孔径为100微米(μm)以下(以下称微小径焊盘)的印制板。但在传统的浸泡处理下,OSP很难渗透到微小径焊盘内。因此,无法充分形成皮膜,在封装工序中无法保持良好的可焊性,导致封装不良的结果。然而,在OSP处理工序中,对上述问题至今没有找到有效的解决方案。为了解决这些问题,我们以喷淋方式进行了OSP处理。通过选择适当的喷嘴进行喷淋处理,把喷射的OSP粒径调整到50微米以下,使OSP药液容易渗透到微小径焊盘内。但是,由于还存在着调整温度的难度,接液量及时间不足等问题,我们考虑到有可能无法在铜表面上充分形成OSP皮膜。因此,通过在低温下迅速形成皮膜的OSP处理,实现了以少量且短时间的喷淋充分形成皮膜。     

Evaluation of characteristic deuterium distributions of ephedrines and methamphetamines by NMR spectroscopy for drug profiling

We have established a method for quantitative analysis of the deuterium contents (D/H) at the phenyl, methine, benzyl, N-methyl and methyl groups of l-ephedrine/HCl, d-pseudoephedrine/HCl and methamphetamine/HCl by 2H NMR spectroscopy. Comparison of the 5 position-specific D/H values of l-ephedrine/HCl and d-pseudoephedrine/HCl prepared by three methods (chemical synthesis, semichemical synthesis, and biosynthesis) showed that chemically synthesized ephedrines and semisynthetic ephedrines have highly specific distributions of deuterium at the methine position and at the benzyl position, compared with the other positions. The classification of several methamphetamine samples seized in Japan in terms of the D/H values at these two positions clearly showed that the methamphetamine samples had been synthesized from ephedrines extracted from Ephedra plants or semisynthetic ephedrines but not from synthetic ephedrine. This isotope ratio analysis method should be useful to trace the origins of seized methamphetamine in Southeast Asia.     

极细高硅型铁尾矿制备超高性能混凝土研究

基于骨料堆积理论和颗粒最紧密堆积理论,利用辽宁地区的高硅型铁尾矿砂替代天然河砂制备绿色新型超高性能混凝土(UHPC),并针对其浆体性能和力学性能开展了研究。结果表明,随着铁尾矿砂替代量的增大,UHPC浆体的流动性逐渐降低,含气量逐渐增大;UHPC试件的抗折强度随着掺量的增大有所上升,但7 d抗压强度随着铁尾矿砂掺量的增大而减小,而28 d龄期的抗压强度随着铁尾矿掺量的增大而增大,并在40%时达到最大值。     

Preparation and Properties of Phosphate Surfactants Containing Ether and Hydroxy Groups

Phosphate surfactants containing ether and hydroxyl groups were prepared by a simple reaction between the corresponding epoxide and the diethyl phosphate. The relationships between the structure and colloidal properties were evaluated in terms of the critical micelle concentration (CMC), γCMC, foaming ability, and water absorbing and holding abilities. Based on these results, it was concluded that the ether and hydroxy groups synergistically worked together to decrease the CMC and increase the foaming ability. The degree of neutralization remarkably affected the colloidal properties. The highly neutralized states showed a more positive effect on water holding power but an opposite effect on the foaming ability.     

Pipe diameter effect on flow and heat transfer characteristics of ammonia alum hydrate slurries with additives

In this study, pipe diameter effect on flow and heat transfer characteristics of ammonia aluminium sulfate dodecahydrate (ammonia alum hydrate: AlNH₄(SO₄)₂·12H₂O) slurries with drag reducing surfactants and poly(vinyl alcohol) was investigated. Pressure loss and heat-transfer coefficients of ammonia alum hydrate solutions and slurries were measured with double-pipe heat exchangers with different inner tube diameters. Measurement results indicated that pseudo-laminarization by the surfactant caused drag-reduction effect and its saturated magnitude was affected by inner tube diameters. Pseudo-laminarization also produced heat transfer reduction effect and its magnitude was not affected by inner tube diameters. Calculation results of Colburn's j-factor divided by friction factors indicated that heat transportation efficiency of the hydrate solutions/slurries with additives was increased due to the contribution of drag-reduction effect.