果蔬气调库贮藏中温温度控制及气密性措施

近几年果蔬气调库发展迅速,气调库与一般高温温度、湿度控制要求不同,湿湿度控制不但关系到贮藏食品的品质,还会影响到气调库中设定的气体成分,本文详细地讨论了气调贮藏中温度,湿度的控制要求,控制方式,以及实现气调库气密性的措施。     

减压冷藏保鲜贮藏装置的一种湿度补偿方法

介绍了减压保鲜贮藏装置的一种湿度补偿系统,适用于对减压冷藏保鲜贮藏装置进行的湿度补偿。     

包装材料及贮藏温度对板栗贮藏性能的影响

目的 探究5种包装材料在2种不同贮藏温度下对板栗品质的影响。方法 选用PE1膜、PE2膜、抗菌袋、PE/PA1膜、PE/PA2膜分别对板栗进行包装，然后置于常温(25 ℃)、低温(0 ℃)下贮藏，测定果实在贮藏期间的呼吸强度、色度、还原糖含量、淀粉含量、酶活性等指标。结果 在常温贮藏时，相较于PE膜，抗菌袋能够显著抑制板栗的呼吸强度，在贮藏14 d时可较好地抑制板栗的菌落总数和腐烂率的变化。在低温贮藏时，采用抗菌袋和PE/PA膜在贮藏15 d时均有较好的抑菌效果，抗菌袋对板栗腐烂率的抑制效果更为显著，在贮藏60 d时板栗的腐烂率仅为4.44%。在2种温度下，不同的包装材料对栗仁的色泽均无显著影响。结论 采用抗菌袋包装结合低温贮藏能有效抑制板栗在贮藏过程中微生物的生长，延缓其腐烂速度，提高其经济价值。     

湿度对瓦楞纸板蠕变特性的影响

目的通过一系列试验来研究湿度对瓦楞纸板蠕变特性的影响,从而得出瓦楞纸板的蠕变曲线。方法通过对瓦楞纸板进行3种恒定载荷,3种不同湿度处理条件下的蠕变特性研究试验,得出其蠕变曲线,并分别进行研究比较,分析湿度对瓦楞纸板蠕变特性的影响。结果湿度对瓦楞纸板的蠕变都有显著影响。结论瓦楞纸板的蠕变会随着湿度的增加而增大。     

不同压力条件对减压罐贮藏生鲜香菇品质的影响

目的探讨在常温(20℃)下,不同压力条件对香菇减压贮藏效果的影响。方法以常压,(80±5),(55±5),(30±5)kPa等不同压力处理香菇,评定其呼吸强度、失重率、可溶性固形物含量、硬度、相对电导率和多酚氧化酶(PPO)活性等。结果减压贮藏能抑制贮藏初期香菇的呼吸强度(P0.05),并将香菇的呼吸高峰延迟至第8天;减压贮藏能减缓可溶性固形物含量的变化,减少硬度的下降,降低细胞膜的透性(P0.05);减压贮藏压力越低,对香菇PPO活性的抑制作用越强(P0.05),与其他处理组相比,(30±5)kPa处理组在第10天时PPO活性达到最低,为7.43 U。结论减压贮藏在一定程度上能导致香菇的失重率升高,其中(55±5)kPa减压贮藏压力下香菇的可溶性固形物含量、硬度、相对电导率等3个方面效果较佳。     

贮藏条件对樱桃果酒香气成分的影响

目的研究不同贮藏条件(贮藏容器、贮藏温度)对樱桃果酒香气成分的影响。方法采用固相微萃取(SPME)-气相色谱-质谱法测定樱桃果酒香气成分。结果樱桃果酒香气成分共44种,包括酯类、醇类、酸类、酮类、酚类、醛类等;原酒对照组、低温瓶装贮藏组、室温瓶装贮藏组、低温不锈钢罐贮藏组、室温不锈钢罐贮藏组的香气成分分别为30,37,21,41,17种。结论低温不锈钢罐贮藏有利于有效形成或保留樱桃果酒的香气成分。     

低温贮藏中药材的应用总结出总结

自中国加入WTO，中药日益受到国际社会的关注。中药材在贮藏过程中也会受到温度、湿度的影响，其质量品质会发生变化，本文就中药材的低温贮藏的应用进行了总结论述。     

基于PLC的仓库温、湿度智能控制系统设计

该文根据企业仓库对货物的存储要求,设计了基于PLC的仓库温、湿度智能控制系统,根据仓储环境的基本要求,采用PID对温度和湿度进行控制,实现对仓库环境的温度和湿度自动控制的功能。该文设计的PLC温、湿度智能化控制系统的硬件部分主要包括S7-200型PLC、PT100型号温度和DHT11型号湿度传感器等。在软件程序设计方面,该文重点设计了温、湿度信号的采集程序、温、湿度控制程度以及温、湿度调用PID程序。通过以上控制系统软件与硬件能够精确地对仓库温度和湿度进行检测和控制,具有较强的适用性。     

贮藏温度对水产品品质影响的研究现状

本文分析了不同的贮藏温度条件与水产品品质的关系,介绍国内外已进行的贮藏温度变化对水产品品质影响的实验研究现状,指出以往研究的特点,并对今后水产品冷藏链的研究方向提出了建议。     

Evanescent wave optical-fiber sensing (temperature, relative humidity, and pH sensors)

Sensitive and versatile evanescent wave-sensing systems featuring polished optical fiber-based sensor designs with low-cost light sources have been developed for temperature, relative humidity, and pH measurements. The work herein contained describes the fabrication of three types of sensors based on standard silica, single-mode fibers previously subjected to a lateral polishing of the cladding. Temperature sensing through oils whose refractive index varied linearly with temperature showed applicability with up to 5 dB//spl deg/C for a 5/spl deg/ range. Polyvinyl alcohol films on the fibers showed almost 10-dB linear variation from 70% to 90% relative humidity. Sol-gel trapped dyes as thin films on the polished surface were capable of performing 15-dB output variation (although not linearly) for pH ranging from 2 to 11.     

Effect of relative humidity on energy absorption properties of honeycomb paperboards

The effect of relative humidity (RH) on the energy absorption characteristics of honeycomb paperboard is investigated experimentally. Results indicate that RH has no significant effect on plateau stress, or energy absorption capacity of honeycomb paperboard in RH range between 40–75%, but its energy absorption properties decrease substantially with the increasing of RH when the RH exceeds 75%. It is concluded that RH is a significant consideration for honeycomb paperboard as a cushioning material used in extremely humid environments most probably encountered in south‐east coast of China, while under ordinary circumstances, there is no need to consider the effect of RH. Energy absorption diagram based on the effect of RH is constructed from the stress‐strain curves obtained from tests, and its application for a given energy absorption task is exemplified. The model established in this paper could be used for practical application for the designing optimization and material selection of packaging products in actual logistics environments. Copyright © 2010 John Wiley & Sons, Ltd.     

Influence of concrete relative humidity on the amplitude of Ground-Penetrating radar (GPR) signal

In order to improve radar technique efficiency and to offer innovative applications as non-destructive evaluation tools for civil engineering structures, the authors studied the influence of concrete moisture on GPR sounding. The presence of water in concrete leads to modifications of its electromagnetic properties and thus to specific effects upon waveform characteristics. In particular, the paper focuses on amplitude variations during processes which consume free water (hydration, drying). Radar measurements were carried out on laboratory samples using a commercial ground-coupled antenna of 1.5 GHz central frequency, while relative humidity profiles of the concrete were provided by specific sensors placed at various heights through the concrete samples. An increase in the amplitude of signals propagating through the samples was observed during hydration and drying. Moreover, radargrams recorded during the test also show that the direct wave propagating at the surface of the samples, is ereatly influenced by the evolution of concrete moisture. Concrete hygrometric measurements performed at the same time provide quantitative information on the effect of moisture reduction on radar signals.     

室内相对湿度对空调器性能及舒适性的影响

在室外工况及室内干球温度相同,室内相对湿度不同的条件下,实验分析空调器的性能参数的变化情况。实验结果表明,室内相对湿度对空调器的能效比几乎没有影响,但相对湿度较低时空调器的出风温度也较低,相对湿度与温度合理耦合可以实现同等热舒适条件下快速制冷且降低空调器能耗的目的。     

Effect of relative humidity on the optical and waveguide properties of thin chitosan films

We have measured the optical characteristics of thin films based on various ion forms of chitosan and studied their mutual correlation. Using the spectral ellipsometry and mode spectroscopy techniques, it has been established that the optical characteristics of chitosan depend on the relative humidity (RH) of the ambient medium. All samples are characterized by threshold RH values, at which the optical characteristics exhibit a change. The obtained data allow chitosan to be classified as a promising sensor material with the optical properties controlled by relative humidity of the ambient medium.     

Quenching of luminescent ruthenium(II) complexes by water and polymer-based relative humidity sensors

Water quenching of luminescent [Ru(phen)(2)dppz]Cl(2), [Ru(phen)(2)dppn]Cl(2), and [Ru(4,7-Ph(2)phen)(2) dppz]Cl(2) (phen = 1,10-phenanthroline; 4,7-Ph(2)phen = 4; 4,7-diphenyl-1,10-phenanthroline; dppz = dipyrido[3,2-a:2'3'-c]phenazine; dppn = benzodipyrido(a:3,2-h:2',3'-j)phenazine) complexes was studied in acetonitrile and in polymers. The polymers contained hydrophobic and hydrophilic components to control mechanical properties and were designed to absorb water with changing humidity and, thus, affect the emission intensity and lifetime. Quenching by water in mixed solvents and in polymers was shown to arise from a combination of diffusional and static ground-state associational quenching. The factors controlling polymer properties are discussed. The systems can be tailored to give a wide range of responses or function as a binary sensor at a fixed humidity level.     

Effect of annealing temperature on structural,optical and humidity sensing properties of indium tin oxide (ITO) thin films

Tin doped indium oxide (ITO) thin films were prepared by sol–gel spin coating method with In (NO₃)·3H₂O and SnCl₄·5H₂O as indium and tin sources, respectively. The as deposited samples were annealed at various temperature such as, 300, 400, 500 and 600?°C for 2 h in ambient atmosphere. The grown ITO thin films are polycrystalline in nature with cubic structure of In₂O₃ with the space group La3 and the results are in good agreement with the standard JCPDS data (card no#06-0416). In addition crystalline size increases with increasing annealing temperature from 25 to 55 nm. Polycrystalline with uniform smooth surface was observed by SEM micrographs. The optical band gap energy was found to be decreased from 3.85 to 3.23 eV as the annealing temperature is increased from 300 to 600?°C. The humidity sensing performance (high sensitivity and fast response time) was significantly improved for 600?°C thin films samples, which is probably due to smaller energy band gap and physisorption between the water molecules and the surface of the thin films. The films were further characterized by PL and EDS analysis. The effect of temperature on humidity sensing mechanism of ITO thin films is also discussed.     

Effect of the relative humidity on the fibre morphology of polyamide 4.6 and polyamide 6.9 nanofibres

To obtain uniform and reproducible nanofibres, it is important to understand the effect of the different electrospinning parameters on the nanofibre morphology. Even though a lot of literature is available on the electrospinning of nanofibres, only minor research has been performed on the effect of the relative humidity (RH). This paper investigates the influence of this parameter on the electrospinning process and fibre morphology of the hydrophilic polyamide 4.6 and the less hydrophilic polyamide 6.9. First, the electrospinning process and deposition area of the nanofibres is examined at 10, 50 and 70 % RH. Subsequently, the effect of the polyamide concentration and solvent ratio on the fibre morphology is investigated using scanning electron microscopy and differential scanning calorimetry. It was found that the nanofibre diameter decreased with increasing RH. This resulted in less stable crystals for polyamide 4.6 while electrospinning of polyamide 6.9 at higher RH led to slightly more stable crystals. In conclusion, the water affinity of a polymer is an important factor in predicting the nanofibre morphology at different humidities.     

The effect of temperature and humidity on electrospinning

Electrospinning is a process that generates nanofibres. Temperature and humidity affect this process. In this article the influence of humidity and temperature on the formation and the properties of nanofibres are studied using cellulose acetate (CA) and poly(vinylpyrrolidone) (PVP) as target materials. The experiments indicate that two major parameters are dependent of temperature and have their influence on the average fibre diameter. A first parameter is the solvent evaporation rate that increases with increasing temperature. The second parameter is the viscosity of the polymer solution that decreases with increasing temperature. The trend in variation of the average nanofibre diameter as a function of humidity is different for CA and PVP, which can be explained by variations in chemical and molecular interaction and its influence on the solvent evaporation rate. As the humidity increases, the average fibre diameter of the CA nanofibres increases, whilst for PVP the average diameter decreases. The average diameter of nanofibres made by electrospinning change significantly through variation of temperature and humidity.     

冷冻实验箱温湿度控制方法的改进

根据食品冻结与储藏保鲜研究需要的恒温恒湿和一定空气流速的实验环境条件,在原有低温箱的基础上进行了改进,使其具有模拟低温环境的功能.本文重点研究恒温恒湿和采用电子膨胀阀的控制方式,并介绍一系列实验的结果.