优良发酵果蔬原酱专用乳酸菌的筛选及鉴定

采用目的平板梯度稀释法,从自然发酵果蔬原浆及中外泡菜老液中分离到22株乳酸菌。采用MRS(pH2.0)初筛平板和MRS(30%葡萄糖)复筛平板,筛选出4株耐酸、耐高糖乳杆菌。对其进行了pH值、酸度、活菌数等果蔬酱发酵性能测试研究,其中两株发酵产酸速度快、发酵性能优异、发酵果蔬酱风     

用于波分复用系统的多峰干涉滤光片

介绍了用于波分复用系统的多峰干涉滤光片的设计原理,提出了滤光片透射峰位置的确定方法,讨论了影响滤光片半宽度和截止度的因素,给出了滤光片的膜厚容差分析结果,表明透射率监控标准偏差在<0.5%范围内,可以得到波形良好的多峰滤光片,最后给出了实验结果.     

光学线性调频步进信号合成与高分辨测距演示

利用分立激光器合成大带宽线性调频步进信号(FSCS)激光信号源以实现高分辨测距。依据FSCS信号测距原理,数值计算了激光器各参数对合成FSCS信号的影响及其误差容限。计算表明,在各激光器参数误差中,起始频率和起始时间误差是引起合成FSCS信号测距分辨力恶化的最主要因素。另外,利用一台中心波长1550 nm、线宽为150 kHz的线性调波长激光器,通过光学斩波方式,模拟产生了合成FSCS信号,进行了高分辨力的测距演示。理论分析与实验结果表明,采用分立激光器合成高分辨力测距FSCS信号是可行的。     

β-Expectation tolerance regions for a generalized multivariate model with normal error variables

In this paper a procedure of construction of β-expectation tolerance regions in the framework of the structural method of inference has been developed. The procedure has been applied to the generalized multivariate model and the β-expectation tolerance region for this case has been constructed assuming the normal distribution for the error variables of the model.     

Mechanical Properties and Flow Behavior of Polymers for Enhanced Oil Recovery

The mechanical properties and flow behavior in porous media of three different polymer systems including a hydrophobically modified acrylamide-based copolymer (HMSPAM), a partially hydrolyzed polyacrylamide (HPAM), and a polysaccharide (xanthan gum) were evaluated to establish their functional differentiation as mobility control agents in enhanced oil recovery (EOR). The rheological properties of the polymers were described by the power-law model to investigate their non-Newtonian behavior. The first normal stress difference (N₁) and Weissenberg number (W_e) were also used to compare their elastic properties. The experimental results showed that, at comparable shear viscosity, HMSPAM exhibited significant elasticity compared to HPAM and xanthan gum. Shear resistance tests indicated that all of the polymers experienced an extra stress when converging into a capillary tube due to the “entrance effect.” Xanthan gum was the most mechanically stable polymer. Moreover, HMSPAM showed the superior reformability which was quantified by the regained viscosity with relaxation time. This could be explained by the rapid re-association of the hydrophobic interactions. Sandpack flood tests indicated that HMSPAM rendered extremely high mobility control ability during polymer flooding suggesting its potential in EOR. However, this polymer also experienced significant retention within the porous media (potential injectivity and plugging problems), which may be attributed to the formation of bulky associative polymer networks. In this work, UV spectrometry was employed to monitor the concentration of the produced polymer solutions and quantify the polymer retention within porous media. This analytical approach offers great reliability and simplicity. It was concluded that the use of a particular polymer system depends on the oil reservoir conditions and the target EOR application.     

属间远缘杂交水稻耐旱性生理特性的比较研究

采用在ＹＯＳＨＩＤＡ水稻专用培养营养液中添加一定量的ＰＥＧ ６０００的方法，比较研究了模拟干旱胁迫条件下属间远缘杂交新型水稻品种“远诱１号”（Ｙ）及其水稻亲本“圭６３０”（Ｇ）、高梁亲本“桃长红”（Ｔ）以及生产推广杂交组合“汕优６３”（Ｓ）等试验材料某些生态生理特性的差异。研究结果表明，在－１．０ＭＰａ的高渗胁迫下，Ｙ、Ｇ、Ｔ的萌发系数均有不同程度的下降，正常培养条件下的萌发系数ＧＣ分别为３６．９     

PEMFC催化剂的研究：自制抗CO中毒Pt-Ru/C电催化剂的性质

用胶体法制备了抗CO中毒PEMFC阳极Pt-Ru/C电催化剂（标记为THYT－2）,对 比研究了THYT－2与Johnson Matthey (JM)公司同类品牌Pt-Ru/C催化剂的电化学及 其它物理化学性能。结果表明,THYT－2电催化剂在甲醇燃料电池和CO／H_2（Φ_ (CO) = 1 * 10~(-4)）的氢氧燃料电池中的电催化行为与JM催化剂相当,但THYT－ 2在低浓度CO氢气燃料中的电池性能更好。两种催化剂的其它物理化学性质具有类 似性：XPS分析结果表明THYT－2和JM催化剂 中都有三种不同价态的Pt存在：即金 属态Pt(0)、氧化态Pt(II)和Pt(IV)。HRTEM测试结果表明两种催化剂的粒径处在2 ～3 mn左右,这可能是它们拥有良好电化学性能的主要原因之一。本文还对催化剂 中Pt与Ru组分的分布和相互作用进行了讨论,提出了改进Pt-Ru/C电催化剂的思路 。     

Investigation on the Stability of the Dispersion System of Cross-Linked Polyacrylamide Microspheres

The salt resistance, temperature resistance, and shear stability of a cross-linked polyacrylamide microsphere system are studied by microfiltration, light diffraction analysis, and optical microscopy. The results show that other conditions being equal, the particle diameter of cross-linked polyacrylamide microspheres decreases with increased NaCl concentration. When NaCl concentration is lower than 10,000 mg/L, its effect on the plugging performance of a cross-linked polyacrylamide microsphere system in regard to the nuclear pore membrane is weak in comparison with a linked polymer solution, but the former system has better salt tolerance. Particle diameter decreases with increased swelling temperature. When the swelling temperature is below 90°C, its effect on the plugging performance of the cross-linked polyacrylamide microsphere system in regard to nuclear pore membrane is weak in comparison with the linked polymer solution, but has better temperature tolerance. Particle size shows little change, with shearing rate being increased, while the shape remains about the same and the effect of shearing on the plugging performance of the cross-linked polyacrylamide microsphere dispersion system in regard to the nuclear pore membrane is weak in comparison with the linked polymer solution, but has better shear stability. The salt tolerance, temperature tolerance, and shear stability of microspheres are associated with a particular cross-linked structure.     

可变误差多面体法同时测定复方新诺明中二组分的含量

以可变误差多面体法处理多波长吸光光度数据同时测定了复方新诺明制剂模样和五个批号实际样品中磺胺甲恶唑（ＳＭＺ）,甲氧苯氨嘧啶（ＴＭＰ）的含量,１１份模拟样中ＳＭＺ、ＴＭＰ的回收率分别为９９．８％和１００．３％,复方新诺明片和注射液的测定结果与药典方法一致。     

具有优异甲醇耐受性的Rh掺杂PdCu有序金属间化合物纳米粒子增强氧还原电催化

Direct methanol fuel cells (DMFCs), as one of the important energy conversion devices, are of great interest in the fields of energy, catalysis and materials. However, the application of DMFCs is presently challenged because of the limited activity and durability of cathode catalysts as well as the poisoning issues caused by methanol permeation to the cathode during operation. Herein, we report a new class of Rh-doped PdCu nanoparticles (NPs) with ordered intermetallic structure for enhancing the activity and durability of the cathode for oxygen reduction reaction (ORR) and achieving superior methanol tolerance. The disordered Rh-doped PdCu NPs can be prepared via a simple wet-chemical method, followed by annealing to convert it to ordered phases. The results of transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), power X-ray diffraction (PXRD) analysis and high resolution TEM (HRTEM) successfully demonstrate the formation of near-spherical NPs with an average size of 6.5 ± 0.5 nm and the conversion of the phase structure. The complete phase transition temperatures of Rh-doped PdCu NPs and PdCu are 500 and 400 ℃, respectively. The molar ratio of Rh/Pd/Cu in the as-synthesized Rh-doped PdCu NPs is 5/48/47. Benefitting from Rh doping and the presence of the ordered intermetallic structure, the Rh-doped PdCu intermetallic electrocatalyst achieves the maximum ORR mass activity of 0.96 A·mg^-1 at 0.9 V versus reversible hydrogen electrode (RHE) under alkaline conditions—a 7.4-fold enhancement compared to the commercial Pt/C catalyst. For different electrocatalysts, the ORR activities follow the sequence, ordered Rh-doped PdCu intermetallics > ordered PdCu intermetallics > disordered Rh-doped PdCu NPs > disordered PdCu NPs > commercial Pt/C catalyst. In addition, the distinct structure endows the Rh-doped PdCu intermetallics with highly stable ORR durability with unaltered half-wave potential (E_1/2) and mass activity after continuous 20000 cycles, which are higher than those of other electrocatalysts. Furthermore, the E_1/2 of the Rh-doped PdCu intermetallics decreases by only 5 mV after adding 0.5 mol·L^-1 methanol to the electrolyte, while the commercial Pt/C catalyst negatively shifts by 235 mV and a distinct oxidation peak can be observed. The results indicate that the ORR activity of the Rh-doped PdCu intermetallic electrocatalyst can be well maintained even in the presence of poisoning environment. Our results have demonstrated that Rh-doped PdCu NPs with ordered intermetallic structures is a potential electrocatalyst toward the next-generation high-performance DMFCs.