AKD施胶增效剂

探讨用PAE作为漂白苇浆AKD中性施胶生产胶印书刊纸的增效剂.结果表明:用PAE作AKD的施胶增效剂可以明显缩短获得成纸最终施胶度的时间.与阴离子捕集剂一起加入到浆料中增效效果较好,尤其是PAE用量为0.01%最好.纸页熟化1 h就可得到较好的施胶度,并且与没有加入增效剂的纸页熟化3h的施胶度差不多.用AKD施胶增效剂可以大大缩短取得施胶度的时间,对AKD施胶的纸页施胶度滞后现象有明显的改善作用.     

Design of power-controlled class1 Bluetooth CMOS power amplifier

In this paper, an RF power amplifier intended for class 1 Bluetooth application is designed using 0.35 µm CMOS technology. A layout-aware macromodel for the BSIM3v3 MOSFET transistor for RF applications including substrate effect is investigated and used in this design. The model is validated for a 0.35 μm CMOS process using a transistor with total width of 90 μm and 18 fingers and it shows excellent agreement with the f_t and S-parameter measurement data up to 6 GHz. The effects of pads and bond wires are also taken into consideration during the design process of the PA. After post-layout simulations, the amplifier delivers an output power of 19 dBm with 33.7% PAE under 3.3 V supply. This amplifier has a power control feature; its two stage circuit utilizes a cascode configuration in its first stage in order to use its bias pin as a power control input for the amplifier. Using this method, the power control range can be decreased down to 1.4 dBm which satisfies the Bluetooth standard. The chip is fabricated and is currently under testing.     

醚化改性PAE树脂性能的研究

该文探讨了醚化改性剂对PAE树脂的改性方式和改性剂用量,并对改性PAE树脂进行表征,研究了改性PAE树脂的应用效果.结果显示：醚化改性剂可以对PAE树脂进行改性,改性后提高了PAE树脂的增干强效果;醚化剂对PAE树脂的末端改性优于过程改性;醚化剂的较佳用量为质量分数15％（对改性PAE树脂总固含量）;当改性后的PAE树脂用量为质量分数0.5％（对绝干浆）时,与改性前相比,能够进一步提高纸张干抗张指数约3％,而湿抗张指数降低约19％,耐折度提高约9％,撕裂指数提高约19％,内结合强度提高约37％.     

苯乙烯改性PAE乳液的合成条件探讨及其在瓦楞原纸中的应用

通过在过硫酸铵-亚硫酸氢钠氧化还原引发体系下用苯乙烯对PAE进行接枝改性得苯乙烯改性PAE乳液,详细探讨了乳化剂种类、pH值、丙烯酸加入量、保温时间、引发剂用量、苯乙烯/PAE的比例对乳液性能和效果的影响,然后利用红外光谱对其结构进行了表征,最后探讨了乳液不同用量对瓦楞原纸的增强效果。结果表明,乳液添加量为1.0%（对绝干浆）时效果较好,纸张的环压指数、挺度、抗张指数、耐破指数和耐折度可分别比空白样提高19.75%、27.02%、30.72%、32.06%和80%。     

高效合成树脂在造纸中的应用研究进展

就常用的新型高效合成树脂在造纸工业中的应用和研究进展做了简要的介绍。     

等平面化SiC MESFET的研制

在原有设计以及工艺的基础上,采用了器件表面等平面化处理及侧壁钝化工艺,器件工作电压大幅度提高,截止漏电流降低约两个数量级,跨导提高1.5mS/mm。2GHz下测试,微波功率附加效率提高10%左右,增益平均提高了2dB,在VDS=60V的条件下单管功率输出达到了86.5W。经过内匹配和功率合成研制成大功率的SiC脉冲功率管的综合性能较好,在250W的输出功率下,器件仍然保持高达10.5dB的高增益,功率附加效率30%。台阶仪和扫描电镜观测表明,台阶高度已经大大降低,侧壁得到了钝化,尖锐突起和凹坑都已经变得平缓。     

其他助剂作用下PAE湿强剂与纤维吸附特性的研究

通过紫外可见分光光度法研究了在添加絮凝剂和干强剂的条件下,PAE湿强剂在阔叶木浆、针叶木浆、混合浆中的吸附量和吸附率。结果表明,PAE湿强剂在314nm处有特征吸收峰;与针叶木浆相比,PAE湿强剂在阔叶木浆中有更高的吸附量和吸附率;添加絮凝剂和干强剂能够显著提高PAE湿强剂的吸附量和吸附率。     

Characteristics of Carboxymethyl Hemicellulose (CMX) and Its Strengthening Mechanism

In this study,three kinds of rough-wrought hemicelluloses(RHCs)were obtained via alkali extraction on different raw materials.One was untreated Phyllostachys edulis powder;the second was obtained via benzyl alcohol extraction of Phyllostachys edulis powder;and the third was holocellulose of Phyllostachys edulis powder.Carboxymethyl hemicelluloses(CMXs)were prepared by the alkalization and etherification of RHCs and were used to enhance the tensile strength of household paper.The results demonstrated a synergistic effect between CMX and polyamide epichlorohydrin resin(PAE),and the addition of small amount of CMX(0.35 kg/t pulp)can significantly improve the dry and wet tensile indices of paper.Study results of CMX strengthening mechanism revealed that the addition of CMX can improve the retention of PAE,especially the fine fiber,due to the adsorption of charges.The use of CMX in paper not only saves production costs but also reduces the proportion of long fiber,which is beneficial to the closed circulation and treatment of white water.     

Common source power amplifier design for 5G application in 28-nm UTBB FD-SOI technology

The telecommunication market examines a highly growing demand for RF mobile devices where low latency and high performance are ongoing improvement. The power amplifier (PA) is a major element of the radio frequency front-end; especially if power consumption and bandwidth are considered. This paper presents the design of 5G mm-wave PA using both Common Source Class-AB and Class-J topologies utilizing 28-nm UTBB FD-SOI technology and its body bias technique. Upon taking into consideration the parasitic extraction of the transistor, RF pads, and interconnection to ground, a comparison is made and the theoretical effectiveness of Class-J topology for single stage large signal amplification is simulated. Moreover, two distinct transistors - widths of 250 µm and 350 µm - are simulated where each has its own topology in order to study the impact of increasing the width on the performance of the PA. The stability of the designed Power Amplifiers is taken into consideration and the unconditional stability conditions are approved. While 5G spectral band is not yet specified and determined, recent studies proved that the 28 GHz band is particularly effective for 5G mobile standardization.     

改进型宽带Doherty功率放大器的设计

根据Doherty技术,设计了一款改进型宽频带功率放大器。在设计过程中,分析了λ/4线对Doherty功率放大器(DPA)的影响。通过对阻抗比的研究,在理论上延拓了功放的带宽。此外,应用不对称功率输入结构来克服阻抗比变化所带来的非理想调制效应。为了证明文中的理论分析,采用飞思卡尔公司的LDMOSFET功放管MRF6S20010,最终设计实现了一款工作于1 900～2 200MHz的宽频带Doherty功率放大器。测试结果显示,改进型宽带功放相对于传统Doherty功率放大器有很大的优势,可用于无线通信领域。