Green and Effective Ammonium Carbonate-assisted Process for Drying Hemicellulose Obtained through Alkali Extraction of Bleached Bamboo Kraft Pulp

Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.

Optimized Synthesis of Carbon Aerogels via Ambient Pressure Drying Process as Electrode for Supercapacitors

Carbon aerogels were synthesized via ambient pressure drying process using resorcinolformaldehyde as precursor and P123 to strengthen their skeletons. CO2 activation technology was implemented to improve surface areas and adjust pore size distribution. The synthesis process was optimized, and the morphology, structure, adsorption properties and electrochemical behavior of different samples were characterized. The CO2-activated samples achieved a high specific capacitance of 129.2 F/g in 6 M KOH electrolytes at the current density of 1 m A/cm^2 within the voltage range of 0-0.8 V. The optimized activation temperature and duration were determined to be 950 ℃ and 4 h, respectively.

Direct Patterning of Carbon Nanotube via Stamp Contact Printing Process for Stretchable and Sensitive Sensing Devices

Flexible and wearable sensing devices have broad application prospects in bio-monitoring such as pulse measurement,motion detection and voice recognition.In recent years,many significant improvements had been made to enhance the sensor’s performance including sensitivity,flexibility and repeatability.However,it is still extremely complicated and difficult to prepare a patterned sensor directly on a flexible substrate.Herein,inspired by typography,a lowcost,environmentally friendly stamping method for the mass production of transparent conductive carbon nanotube(CNT)film is proposed.In this dry transfer strategy,a porous CNT block was used as both the seal and the ink;and Ecoflex film was served as an object substrate.Welldesigned CNT patterns can be easily fabricated on the polymer substrate by engraving the target pattern on the CNT seal before the stamping process.Moreover,the CNT film can be directly used to fabricate ultrathin(300μm)strain sensor.This strain sensor possesses high sensitivity with a gauge factor(GF)up to 9960 at 85%strain,high stretchability(>200%)and repeatability(>5000 cycles).It has been used to measure pulse signals and detect joint motion,suggesting promising application prospects in flexible and wearable electronic devices.

改进型太阳能–干法碳酸盐系统的燃煤电站灵活性碳捕集方案分析

由于CO2排放对全球气候变化的显著影响导致燃煤电站的碳捕集问题受到广泛关注。采用干法碳酸盐(dry carbonate process,DCP)捕集低温烟气中CO2相比于传统钙循环方法(calcium cycle,CaL)具有诸多优势,且太阳能可用于提供吸附剂再生所需热量,从而取代汽轮机中低压抽汽。然而,现有研究并未改善DCP操作流程,传统的设备布置不仅增加热量损失,还增加了投资成本。研究以600MW燃煤电站尾部烟气为对象,通过去除DCP中再生器和再沸器,提出槽式太阳能集热器直接加热吸附剂的改进型方案,即吸附剂再生在集热管道中进行,不仅降低设备投资和运行成本,而且实现DCP工艺与燃煤电站解耦,消除DCP对电站蒸汽循环依赖,进一步提升系统操作的灵活性,显著增加集成系统的技术经济优势。选用EBSILON和Aspen plus构建燃煤电站与改进型方案模型,全面提升了改进型方案灵活运行过程的装置性能和年发电量,为系统的设备检修提供足够时间,缓解了瞬态气候条件的影响,研究结果将为改进型太阳能-DCP系统的应用提供有利指导。

干姜炮制刍议

[目的]探讨汉州干姜与姜炭的炮制方法。[方法]按照《本草经集注》记载的方法炮制汉州干姜,用不同的切制方法炮制姜炭,比较炮姜、黑姜、姜炭的区别。[结果]汉州生姜两次去皮浸泡后晒干,装瓮缸,通过实践发现并没有发酵现象,而将浸泡后的生姜直接装入瓷罐中可以发酵。姜炭炮制的关键在于干姜的切制,切块是正确的方法,否则无论是清炒、火煨还是研粉,均会导致炮制过度。由于炮制方法的不同,不能简单地以干姜表面的黑褐色作为姜炭的火候标准。古人所谓黑姜,实际上相当于现在的姜炭;而古人所谓里外通黑的姜炭,现代则认为系炮制过度。[结论]姜炭炮制的关键在于干姜切块,黑姜与姜炭是两个不同的炮制品种。汉州干姜的炮制方法,值得进一步研究。

X-ray computed tomography of adhesive wicking into carbon foam

Laser target components consist of multicomponent porous and nonporous materials that are adhesively bonded together.In order to assess the extent and quantity of adhesive wicking into porous foam, micro X-ray computed tomography(CT)and image processing software have been utilized. Two different laser target configurations have been assessed in situ and volume rendered images of the distribution and quantities of adhesive have been determined for each.