Compact circular-patch-based bandpass filter for ultra-wideband wireless communication systems

Ultra-wideband (UWB) is a radio technology that enables low-power-level, short-range, and wide-bandwidth communication, and it has been widely applied in personal area networks, precision geolocation, medical, surveillance, and vehicular radar systems. Since Federal Communications Commission released the unlicensed use of the UWB range (3.1–10.6 GHz), a significant attention has been paid to the development of UWB devices, particularly UWB bandpass filters. In this paper, we propose a novel UWB bandpass filter based on circular patch resonator that is grounded by via and perturbed by slits and defected ground structures. The resonator’s behaviour is analysed in detail and it is shown that its specific configuration allows a flexible control of the three lowest resonant modes, which are used to form UWB passband. To demonstrate the potential of the resonator, a UWB filter has been designed, fabricated, and measured. The filter is characterized by the insertion loss lower than 1 dB and return loss higher than 17 dB within the passband, as well as by very small group delay variation of only 0.07 ns. Also, the filter exhibits suppression higher than 19 dB up to 30 GHz, and very small overall dimensions of only 0.31λ_g × 0.31λ_g, and thus it outperforms other published UWB filters.     

我国食品中铬污染现状及健康风险

铬是人体必需的微量元素,但摄入过多会对人体产生危害。近年来食品中铬的污染问题引发了人们的关注。本文综述了我国近年来食品中铬污染状况,分析其来源及危害,结合国内外铬的限量标准和风险评估提出相应的措施,为加强食品中铬的研究,确保食品安全提供科学依据。     

2006-2007年福建省地产茶叶中有机氯农药残留调查

目的了解福建省地产茶叶中有机氯农药残留现状。方法2006-2007年在福建省主要产茶地随机抽取不同品种茶叶共72份,参照GB/T5009.19—2003《食品中六六六、滴滴涕残留量的测定方法》,采用毛细管气相色谱法进行检测。结果所测72份茶叶中,六六六残留量合格率为95.8%;滴滴涕残留量合格率为63.9%。六六六的主要残留成分为γ-HCH,滴滴涕的主要残留成分为p,p′-DDE。闽南地区的有机氯农药残留远高于闽北地区。结论福建省地产茶叶中有机氯农药残留状况不容乐观,应引起重视,加强监管。     

Improved Stable Indocyanine Green (ICG)‐Mediated Cancer Optotheranostics with Naturalized Hepatitis B Core Particles

In recent years, hepatitis B core protein virus‐like particle (HBc VLP) is an impressive biomaterial, which has attracted considerable attention due to favorable properties such as structural stability, high uptake efficiency, and biocompatibility in biomedical applications. Heretofore, only a few attempts have been made to apply it in physical, chemical, and biological therapy for cancer. In this study, a tumor‐targeting RGD‐HBc VLP is first fabricated through genetic engineering. For image‐guided cancer phototherapy, indocyanine green (ICG) is loaded into RGD‐HBc VLP via a disassembly/reassembly pathway and electrostatic attraction with high efficiency. The self‐assembled stable RGD‐HBc VLP significantly improves body retention (fourfold longer), aqueous stability, and target specificity of ICG. Remarkably, these positive reformations promote more accurate and sensitive imaging of U87MG tumor, as well as prolonged tumor destruction in comparison with free ICG. Moreover, the photothermal and photodynamic effect on tumors are quantitatively differentiated by multiple linear regression analysis. Overall, less‐potent medicinal ICG can be perfectly rescued by bioengineered HBc VLP to realize enhanced cancer optotheranostics.     

电喷雾-离子迁移谱法快速筛查保健品和中成药中5种违禁化学药物

目的建立电喷雾-离子迁移谱(electrospray ionization-ion mobility spectrometry,ESI-IMS)技术快速筛查改善睡眠类保健食品和中成药中非法添加地西泮、咪达唑仑、硝西泮、阿普唑仑、巴比妥等5种化学药物的分析方法。方法样品用乙腈超声提取,90%乙腈水溶液稀释后ESI-IMS直接测定。在正离子模式下检测地西泮和咪达唑仑,在负离子模式下检测硝西泮、阿普唑仑、巴比妥,基质外标法定量。结果 5种化合物在各自浓度范围内线性关系良好,相关系数均大于0.99。地西泮、咪达唑仑、巴比妥、硝西泮、阿普唑仑的检出限分别为0.20、0.50、2.00、8.00、8.00mg/L,平均回收率为78.7%~113.8%,相对标准偏差(RSD,n=6)小于10%,与液相色谱-串联质谱(1iquid chromatography-tandem mass spectrometryLC-MS/MS)检测结果一致。结论本方法快速准确,可实际应用于改善睡眠类健康产品中非法添加地西泮、咪达唑仑、硝西泮、阿普唑仑、巴比妥等5种违禁药物的筛查。     

二阶导数恒能量同步荧光法快速测定海产品中的苯并(a)芘

海产品中的多环芳烃主要来自于水体污染,而苯并(a)芘是公认的多环芳烃指标,本文针对海产品中的苯并(a)芘含量的检测,建立了简单快速的海产品中的苯并(a)芘含量的二阶导数恒能量同步荧光检测法。海产品样品经过微波辅助皂化萃取后,正己烷萃取液被旋蒸干,后再溶解于二氯甲烷溶液中,以二阶导数恒能量同步荧光光谱法检测,设定恒能量差为1400 cm-1,扫描范围为300~500 nm,对其中的苯并(a)芘进行快速检测,根据海产品样品的谱图特性,用负峰-基线法读荧光强度值,连续标准加入法进行定量分析,整个光谱扫描所需时间只需1 min。对实际样品检测回收率在80.5%~118.2%之间,检测限为0.10μg/kg,定量限为0.34μg/kg,线性范围为0.34~250μg/kg。对海产品样品的荧光检测结果与HPLC-FL检测结果基本一致,对有证多环芳烃标准物质的检测结果与参考值一致。     

响应面法优化海地瓜皂苷提取工艺

目的:以海地瓜为原料,开展了海地瓜皂苷的提取工艺研究。方法:在单因素分析的基础上,采用了响应面法分析了乙醇浓度、料液比、提取温度、提取时间等因素对海参皂苷得率的影响,优化获得最佳的海地瓜皂苷提取工艺为:乙醇浓度为79%,提取温度为73.5℃,提取时间为2.75 h,料液比为1∶1.7 g/m L。对海地瓜皂苷的影响由大到小依次为乙醇体积、乙醇浓度、提取时间和提取温度。在该工艺下提取海地瓜皂苷得率为0.378%。与模型预测值一致。结论:响应面分析法确定的提取条件合理,验证值与预测值接近,可以用于海地瓜皂苷的提取工艺优化。      

电喷雾-离子迁移谱法快速筛查保健酒饮料中3种壮阳类药物

目的建立电喷雾-离子迁移谱(ESI-IMS)快速筛查保健酒饮料中违法添加西地那非、硫代艾地那非和伐地那非3种壮阳类违禁药物的方法。方法样品经乙腈超声提取,稀释定容后直接测定。以ESI作为电离源,空气作为迁移气体,在正离子模式进行检测,基质外标法定量。结果西地那非、伐地那非、硫代艾地那非分别在1.25~12.50、2.00~20.00、1.00~10.00 mg/L范围内线性关系良好,相关系数(r)均大于0.99,3种违禁药物的检测限分别为0.50、0.80、0.40 mg/L。平均回收率为93.33%~121.17%,相对标准偏差(RSD)为2.65%~10.00%,实际样品检测与气相色谱-质谱联用法确证结果一致。结论该方法快速简便,结果准确可靠,适用于保健酒饮料中非法添加西地那非、硫代艾地那非和伐地那非3种壮阳类违禁药物的快速筛查。     

我国茶叶中稀土元素残留现状及限量标准的探讨

茶叶稀土问题是近年来我国茶叶质量安全问题中的热点,关于茶叶稀土元素限量标准引起各界争论。本文综述了我国茶叶稀土含量残留问题的现状,对造成茶叶中稀土元素含量超标的原因进行初步的分析,对限量标准作出探讨,为今后科学制定茶叶中稀土的限量标准,加强对茶叶监管提供参考。     

2011—2015年厦门市食物中毒流行病学特征分析

目的分析2011—2015年厦门市食物中毒的流行病学特征,了解食物中毒的规律和特点,为预防和控制食物中毒的发生提供依据。方法用描述性流行病学方法对2011—2015年厦门市食源性疾病报告系统所收集到的食物中毒资料按发生的时间、地点、病死率、致病因素等进行统计分析。结果 2011—2015年厦门市共报告食物中毒事件77起,中毒人数806人,死亡1人。食物中毒事件主要集中在第三季度,8月份最多。中毒原因以微生物性食物中毒为主,占62.34%(48/77),其中主要的致病因子是副溶血性弧菌,而诺如病毒是厦门市2012年后新发现的又一中毒因素。食物中毒主要发生场所是餐饮服务单位,主要集中在岛内思明区。结论加大食品卫生安全的宣传力度,加强对餐饮业的监管力度,建立完善的食物中毒应急处置机制,是减少厦门市食物中毒事件的有效途径。