中国野生葡萄打破休眠研究

用石灰氮对中国野生葡萄进行打破休眠研究。结果表明，在供试的7个野生葡萄株系中，留坝-7、留坝-1、江西-1(绿毛，♀)、通化-3涂抹5～10％石灰氮及平利-7涂抹20％石灰氮有较好的促进萌芽效果。应用同一浓度15％石灰氮处理另外10个野生葡萄株系，唯有秦岭葡萄略阳-4提高萌芽率明显，其余株系表现不明显，或表现有抑制作用，表明不同浓度及同一浓度石灰氮处理中国野生葡萄，在打破休眠方面功效不同。     

Phenolic acids in caryopses of two cultivars of wheat, rye and triticale that display different resistance to pre-harvest sprouting

 This study confirmed the significant role of phenolics in the dormancy of cereal caryopses. Investigations were conducted on two cultivars of wheat (Elena and Alba), rye (Amilo and Dańkowskie Złote), and triticale (Ugo and Bogo), with characteristic deeper or shallow dormancy, respectively. In germination studies, cultivars susceptible to sprouting (Alba, Dańkowskie Złote and Bogo) displayed higher germination percentages than those resistant to sprouting (Elena, Amilo and Ugo). The phenolic acid contents (i.e. free, liberated from soluble esters, and liberated from soluble glycosides) in caryopses were determined by an HPLC method. Caffeic, p-coumaric, ferulic and sinapic acids were the dominant phenolic acids detected. The majority of phenolic acids were found in the form of soluble esters. For all species examined, the levels of phenolic acids liberated from soluble esters and the total phenolic acid contents in caryopses showing shallow dormancy were higher than in those showing deeper dormancy. Slight differences in the UV spectra of extracts of phenolic compounds from caryopses showing shallow or deeper dormancy were noted. Received: 6 April 1999     

Enhanced dormancy due to para-to-ortho hydrogen conversion in insulated cryogenic pressure vessels for automotive applications

A dynamic model has been developed to characterize dormancy and hydrogen loss from an insulated cryogenic pressure vessel that is filled with 99.79%-para liquid hydrogen to reach supercritical conditions. The model considers the thermodynamics and kinetics of the endothermic para-to-ortho conversion that occurs when the stored H₂ heats after the vessel is exposed to ambient conditions for an extended time. The thermal, thermodynamic, and kinetic aspects of the model were validated against experimental data obtained on a 151-L tank designed for service at nominal pressures up to 350 bar. Depending on the initial pressure, temperature, amount of H₂, and the rate of heat gain from the ambient, the endothermic para-to-ortho conversion can extend the loss-free dormancy time by up to 85%. Under conditions in which the endothermic conversion does not materially affect dormancy, it can still significantly reduce the H₂ loss rate and it can even introduce a secondary dormancy period.     

Thermodynamic analysis of the para-to-ortho hydrogen conversion in cryo-compressed hydrogen vessels for automotive applications

Cryo-compressed hydrogen storage has potential applications in fuel-cell vehicles due to its large storing density and thermal endurance. The dormancy of storage can be extended when considering the endothermic conversion of para-to-ortho hydrogen. In present study, a thermodynamic model is established to analyze the effect of the conversion in a cryogenic pressure vessel. The influence of the parameters such as the filling density, initial temperature and initial ortho hydrogen fraction is studied. It is demonstrated that different “transition pressures” for the vessels exist for different filling densities. The conversion can carry out sufficiently and the dormancy can be extended significantly when the designed release pressure of the vessel matches with the transition pressure. The heat of absorption increases with the initial o-H₂ fraction, whereas the peak of conversion rate occurs earlier for the vessel with a large initial o-H₂ fraction. The dormancy can be extended by 163% for the vessel with filling density of 70 kg/m³. The investigations on the effect of the para-to-ortho hydrogen conversion can provide useful guideline for the design of cryo-compressed hydrogen vessels.     

Importance of growth hormones and temperature for physiological regulation of dormancy and sprouting in onions

Onion is one of the most cultivated crops, and its production is increasing worldwide. Proper handling and storage will add huge benefits to the supply of onion to meet the demand of consumers. For storage, it is important to understand onion physiology from the day it was harvested from the field until it reaches the market. This review summarizes the scientific literature related to the physiology of the onion bulb with respect to growth regulators, temperature, and chemical controls. The biochemical changes that occur during dormancy break and sprouting have been discussed in detail. The three main environmental factors that can influence onions during storage are temperature, humidity, and composition of the atmosphere in the storage area. Among these factors, temperature plays a paramount role in the physiology of onion during pre- and postharvest storage. Particular emphasis was given to plant growth hormones (endogenous and exogenous) and their consequent effects with respect to dormancy, sprouting, and biochemical changes that occur in onions.     

Para-H2 to ortho-H2 conversion in a full-scale automotive cryogenic pressurized hydrogen storage up to 345 bar

Hydrogen vehicles offer the potential to improve energy independence and lower emissions but suffer from reduced driving range. Cryogenic pressure vessel storage (also known as cryo-compressed storage) offers the advantage of higher densities than room temperature compressed although it has the disadvantage of cryogenic operating temperatures which results in boil-off when the temperature of the gas increases. In order to understand and optimize the time prior to boil-off, we have examined heat absorption from the transition between the two quantum states of the hydrogen molecule (para–ortho) in a full-scale (151 L internal volume) automotive cryogenic pressure vessel at pressures and temperatures up to 345 bar and 300 K, and densities between 14 and 67 g/L (2.1–10.1 kg H₂). The relative concentration of the two species was measured using rotational Raman scattering and verified by calorimetry. In fifteen experiments spanning a full year, we repeatedly filled the vessel with saturated LH₂ at near ambient pressure (2–3 bar), very low temperatures (20.3–25 K), varying densities, and very high para-H₂ fraction (99.7%). We subsequently monitored vessel pressure and temperature while performing periodic ortho-H₂ concentration measurements with rotational Raman scattering as the vessel warmed up and pressurized due to environmental heat entry. Experiments show that para–ortho H₂ conversion typically becomes active after 10–15 days of dormancy (“initiation” stage), when H₂ temperature reaches 70–80 K. Para–ortho H₂ conversion then approaches completion (equilibrium) in 25–30 days, when the vessel reaches 100–120 K at ∼50 g/L density. Warmer temperatures are necessary for conversion at lower densities, but the number of days remains unchanged. Vessel dormancy (time that the vessel can absorb heat from the environment before having to vent fuel to avoid exceeding vessel rating) increased between 3 and 7 days depending on hydrogen density, therefore indicating a potentially large benefit for reduced fuel venting in cryogenic pressurized hydrogen storage.     

Supercritical cryo-compressed hydrogen storage for fuel cell electric buses

Liquid hydrogen (LH₂) truck delivery and storage at dispensing sites is likely to play an important role in an emerging H₂ infrastructure. We analyzed the performance of single phase, supercritical, on-board cryo-compressed hydrogen storage (CcH₂) with commercially-available LH₂ pump enabled single-flow refueling for application to fuel cell electric buses (FCEB). We conducted finite-element stress analyses of Type 3 CcH₂ tanks using ABAQUS for carbon fiber requirement and Fe-Safe for fatigue life. The results from these analyses indicate that, from the standpoint of weight, volume and cost, 2-mm 316 stainless steel liner is preferred to aluminium 6061 alloy in meeting the required 15,000 charge-discharge cycles for 350–700 bar storage pressures. Compared to the Type 3, 350 bar, ambient-temperature H₂ storage systems in current demonstration FCEBs, 500-bar CcH₂ storage system is projected to achieve 91% improvement in gravimetric capacity, 175% improvement in volumetric capacity, 46% reduction in carbon fiber composite mass, and 21% lower system cost, while exceeding >7 day loss-free dormancy with initially 85%-full H₂ tank.     

新疆主栽葡萄品种需冷量的研究

对石河子地区葡萄促成栽培的几个主要品种的休眠需冷量进行了调查,发现在供试的7个品种中以京早晶、京秀的需冷量最低,恒温条件下分别为264、384小时;其次为无核白、巨峰和早生高墨,需冷量均低于800小时;里扎马特和美国红提的需冷量最高,均超过800小时.由此推算石河子地区葡萄结束自然休眠的时间在12月中下旬.另外,打破休眠的实验表明用石灰氮可以提早萌芽.     

预拦截休眠数据提高数据库管理系统性能

首先以预拦截技术挖掘休眠数据，然后分析如何处理休眠数据，解决了数据库管理系统中历史数据累积影响系统性能的问题。     

基于SmartMesh IP技术的无线围岩移动传感器设计

为了解决基于RS-485总线通信的围岩移动传感器在工作面回采过程中线缆容易被扯断,离层数据无法可靠、实时上传的问题,以及现有无线顶板安全监控系统节点数量少、功耗高、实用性差的问题,创新性地提出了一种采用SmartMeshIP无线通信技术的,具有低功耗、自组网特点的无线围岩移动传感器设计方案。对电池电压采集电路、数码管显示电路、光控及遥控电路、元件信号处理电路、报警电路、无线组网模块接口电路六部分硬件电路,及各部分电路低功耗实现方法、电池电量计算与选型以及传感器的软件流程进行了研究。现场应用表明,该传感器无线自组网数据传输稳定可靠,运行功耗低,能够保证在不换电池的情况下工作1年以上。该研究对煤矿安全监测智慧化发展进行了有益的探索。