高耐温精密冷反光镜研制

高耐温精密冷反光镜是应用于影像光学系统的一种常用光学元件,它具有高耐温性、反射可见光、透射红外光的特点。本文介绍了采用低膨胀系数的高耐温性基底材料,利用电子束热蒸发物理气相沉积镀膜方法及离子辅助沉积工艺,制备出了可见光光谱平均反射率高于95%、红外光光谱平均透过率高于85%,膜层耐温性能达到450℃高温下膜层无异常的反光镜产品,并实现了批量生产。

环氧树脂改性及在湿法缠绕成型中的进展

本文介绍了环氧树脂改性的主要研究方向和在湿法缠绕成型中的进展。环氧树脂改性主要包括固化剂选择、树脂增韧以及温度抗性的提升。通过优化固化剂、改进树脂的韧性和耐温性,可以调整环氧树脂的加工工艺和最终性能,以满足多种应用需求。在复合材料纤维缠绕工艺红,本文也梳理总结了关键的树脂开发和改性重点在于工艺适应性、复合材料的力学性能以及热稳定性。总体而言,环氧树脂改性领域仍在发展中,未来的研究将促进技术进步,并为工程领域中高性能树脂产品的应用提供更多可能性。

Tolerance of a Restorer Line R1056 to High Temperature and Its Application in Rice Breeding

The tolerance of a restorer line R1056 of rice and its hybrid combinations to high temperature at flowering stage was evaluated by sowing them at three dif- ferent dates and transplanting them into a greenhouse equipped with heating system at flowering stage. Several important agronomic traits of these rice varieties or combinations were also measured. The results revealed that treated by high temper- ature （38 ℃） at flowering stage, the seed setting rate （70.4%）, percentage of dehis- cent anthers （75.5%）, and pollen number per floret （78） of R1056 were close to those of N22, which is tolerant to high temperature, and significantly higher than those of the rice varieties sensitive to high temperature. The seed setting rate, per- centage of dehiscent anthers, and pollen number per floret of the hybrid combina- tions generated from R1056 were smaller than those of R1056, but higher than those of the rice varieties sensitive to high temperature. R1056 had excellent agro- nomic traits, and good combining ability, and its hybrid combinations had low plant height, numerous panicles and high yield, suggesting that R1056 is not only an ex- cellent rice variety with tolerance to high temperature, but also an excellent restorer in three-line hybrid rice breeding.

Effects of High Temperature Stress on Growth of Stress-Tolerant Rice Seedlings with Resistibility

Two heat-tolerant rice varieties, N5 and TQ, were chosen as test materi- als. Specifically, rice seedlings （leaf age at 2.1）, cultivated in room, were treated at 40 ℃ for 7 d and some indices were measured, including plant height, dry weight, leaf color, proline, malondialdehyde and conductivity. The results showed that high temperature advanced the growth of N5 seedlings, for example, plant height, root length and dry weight of ground parts all increased. However, high temperature prevented TQ seedlings growth, plant height in particular. Furthermore, high temper- ature treatment increased the content of chlorophyll of N5 and had none effects on PSII of N5, with little damages on membrane system. On the other hand, high temperature actually reduced PSII activity of TQ, and seriously damaged TQ mem- brane system. It is speculated that the differences of the two varieties lie on pro- duction or removing capacity of reactive oxide species.

Effects of High Temperature on Activities of Some Protective Enzymes in Mononychellus tanajoa

[Objective] Mononychellus tanajoa is a mite speices recently invaded into China in 2008. Temperature is one of the most important ecological factors affecting the growth and reproduction of M. tanajoa. The objective of the current study was to reveal the effects of high temperature incubation on the activities of some protective enzymes in M. tanajoa at different growth stages. The results would contribute to the understanding of the adaptable distribution of M. tanajoa after its invasion into China, the mechanisms in its invasion, diffusion and ecological adaptation, and the monitor- ing, early warning and effective prevention of its damage. [Method] Six protective enzymes, Le. polyphenol oxidase （PPO）, peroxidase （POD）, ascorbate oxidase （AsA- POD）, catalase （CAT）, superoxide dismutase （SOD） and esterase （EST）, were cho- sen to study their activities after the mites at different growth stages were incubated at a extremely high temperature of 42 ~C for a certain period of time up to 24 h. The activities were measured by spectrophotometric endpoint assay method. [Results] Enzyme activities in M. tanajoa were affected by the high temperature incubation. However, differences in enzyme activity changes were found among different protec- tive enzymes and among different growth stages of M. tanajoa. Activities of PPO, POD, AsA-POD and CAT were significantly increased in the larval mites and female adult mites of M. tanajoa. CAT activity was significantly decreased in protonymph and deutonymph of M. tanajoa. Activities of PPO, POD and AsA-POD in protonymph and deutonymph showed no obvious difference from the control. [Conclusion] The activity changes of some protective enzymes in M. tanajoa following high-temperature treatment are part of its anti-stress reaction mechanism. In mite protonymph and deutonymph, activities of PPO, POD and AsA-POD are similar to the untreated con- trol which may be associated with the thermostability of M. tanajoa. It is concluded that, the long-time stress of extreme temperature may result in the increase of the thermostability of mite individuals, the enhancement of the population thermal stability and subsequently lead to rapid expansion of the population.

Corrosion properties of stainless steel 316L/Ni-Cu-P coatings in warm acidic solution

In order to improve corrosion resistance of stainless steel 316L in warm acidic solution, Ni？Cu？P coatings with high copper and phosphorus contents were deposited onto stainless steel 316L substrates via electroless plating. The structure of the film and its resistance to corrosion in a warm acidic environment were investigated using scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction spectrometry （XRD）, polarization curves, electrochemical impedance spectroscopy （EIS）, and dipping corrosion tests, respectively. The results demonstrate that Ni？Cu？P coatings consist of two types of nodules, which are 19.98% Cu and 39.17% Cu （mass fraction） respectively. The corrosion resistance of the 316L substrate when subjected to a warm acidic solution is significantly improved by the addition of the new type of the Ni？Cu？P coating. The as-plated coatings demonstrate better corrosion resistance than annealed coatings. As-plated coatings and those annealed at 673 K are found to corrode selectively, while pitting is observed to be the main corrosion mechanism of coatings annealed at 773 and 873 K.

Research progress of high temperature resistant nylon 10T

Researches about synthesis and modification of nylon 10T(PA10T)in domestic universities and scientific research institutions are reviewed in this paper.The results show that,due to the different performance requirements,PA10T is studied from the co-polymerization,blending modification and filling modification of these three aspects.Meanwhile,the existing problems are analyzed and the development prospect of PA10T is predicted.

Corrosion evolution of high-temperature formed oxide film on pure Sn solder substrate

The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The results indicate that high-temperature aging accelerates the dehydration of Sn(OH)_(4)in the pre-existing native oxide film to form SnO_(2)and facilitates the oxidation of fresh Sn substrate, resulting in the gradual increase in oxide film thickness and surface roughness with prolonging aging time. However, the corrosion resistance of the film initially is enhanced and then deteriorated with an extending aging time. Besides, the formation and evolution mechanisms of the oxide film with aging time were discussed.

Study on Properties of Anti-Gas Channeling Lightweight Temperature-Resistant Latex Slurry

There is low formation pressure coefficient and high formation temperature in ludong-wucaiwan area. Gas cut and gas channeling happen seriously during oil and gas well cementing. The existing anti-migration additive has only effects on single trait, so it is difficult to meet cementing requirement. According to this situation we could use latex slurry to anti-gas channeling. We have synthesised a set of anti-gas channeling lightweight temperature-resistant latex slurry and formed a new channeling preventing latex slurry through plenty of previous laboratory experiments. Finally the performance of latex slurry on temperature-resistant, anti-gas channeling and the anti-gas channeling of cement paste are studied. The experimental results show that this latex system has strong temperature-resistant and anti-gas channeling, which completely meet the requirement of cementing in this area.

Effects of fibers on mechanical properties of high-performance concrete subjected to elevated temperatures

The compressive strength and ilexural toughness as well as fracture energy of fiber reinforced highperformance concrete （FRHPC） subjected to different high temperatures were studied. The results showed that after exposure at 300,600 and 900℃, the concrete mixes retained 88.1% , 41.3% and 10.2% of the original compressive strength on average, respectively. Steel fiber and polypropylene （PP） fiber were both effective in minimizing the damage effect of high temperatures on the compressive strength. The HPC reinforced with steel fibers showed higher flexural toughness and fracture energy before and after the high-temperature exposures. In comparison, PP fibers had minor beneficial effects on the flexural toughness and fracture energy. The mechanical properties of HPC reinforced with hybrid fibers （steel fiber ＋ PP fiber） were equivalent to or better than those of HPC reinforced with steel fibers alone. In addition, the failure pattern of FRHPC beams changed from pull-out of steel fibers at lower temperatures （20, 300 and 600℃） to tensile failure of steel fibers at higher temperature （900 ℃）.

Fire's effect on chloride ingress related durability of concrete structure

This paper describes the effects of fire on durability of reinforced concrete structures, and points out that fire not only damages the chemical composition and physical structure of concrete by high temperature, but also leads to an additional risk due to the generation of polyvinyl chloride (PVC) combustion gases. A mathematical model is proposed to calculate chloride ingress profiles in fire damaged concrete, so as to explore the service life prediction of the structure. Rapid Chloride Migration (RCM) test was carried out to determine the chloride diffusion coefficients for the application of the mathematical model. Finally, the detected results of a reported case testified to the validity of the mathematical model.

Antioxidant Defense System in Wheat （Triticum aestivum L.） Seedlings under Heat Stress and Revival Conditions

The present investigation was carried out to investigate the effect of heat stress and revival on some antioxidative enzymes and metabolites in leaves of the wheat （Triticum aestivum L.） seedlings of heat susceptible （cv. WH 147 and HS 277） and heat tolerant （cv. WH 1021 and HW 2045） cultivars. Seven days old seedlings grown at 25 ℃ were exposed to 40 ℃ for 6 h and these seedlings were again brought to 25 ℃. The observations were recorded in the leaves of control, stressed and revived seedlings on 2nd and 4th day of revival. For the selection ofthermo-tolerant cultivars, screening of the thirty-six cultivars was done based on wilting of primary leaf and values of chlorophyll fluorescence. The MDA （malondialdehyde） and H2O2 concentration in leaves of wheat seedlings increased at the high temperature. There was enhancement in the activities of antioxidative enzymes, viz. CAT （catalase）, POX （peroxidase）, GR （glutathione reductase） and APX （ascorbate peroxidase） in leaves of the tolerant and susceptible cultivars under heat stress, however, higher percent increase was observed in tolerant cultivars. Heat stress increased the SOD （superoxide dismutase） activity in tolerant cultivars but activity declined in susceptible cultivars. On revival, the activities of the CAT, POX and GR declined in comparison to stressed seedlings but remained higher as compared to control. Ascorbate peroxidase activity remained higher on 2nd day and 4th day of revival in all the cultivars.

A comparative analysis of dielectric properties of oil-paper insulation and polymer materials before and after thermal aging

The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.