菠萝蜜的保鲜及其市场开发前景

介绍了菠萝蜜的基本生物特性,综合分析了食用价值,提出了对其进行速冻或凝胶保鲜的加工方法,这为消费者常年提供营养、美味的热带水果－菠萝蜜成为可能,同时也为加工企业提供了一条合理、有价值的开发途径。     

含铁物质对燃煤污染特性的影响

利用DTA-TG-DTG设备实验研究了FeCl₃、FeCl₂和Fe₂O₃等含铁物质对燃煤污染特性的影响.结果表明:实验所用的几种含铁化合物均能够改变燃煤污染物的排放规律,但不同种类的含铁物质对燃煤污染特性影响机理不同,所取得的污染物减排效果也不同.在煤燃烧以及煤中S与N向SO₂及NO转化的过程中,FeCl₃既起到催化剂的作用,同时又起吸收剂的作用.FeCl₃催化作用表现在降低了SO₂和NO生成反应的表观活化能,使SO₂和NO能够在较低温度时迅速形成,加快了SO₂和NO生成反应的速率.FeCl₃的催化效果与S在煤中的存在形态有关.FeCl₃的吸收作用表现在FeCl₃本身能够参与SO₂的吸收反应生成FeSO₄或Fe₂(SO₄)₃.此外,FeCl₃还能够改变CO的排放特性,即能够改变煤的燃烧特性.FeCl₂对烟气中SO₂、NO和CO排放特性的影响与FeCl₃相似,但影响效果比FeCl₂₃略差.Fe₂O₃也能够降低烟气中SO₂和NO的体积分数,但Fe₂O₄只是吸收剂,对SO₂和NO的生成过程没有催化作用.Fe₂O₃对CO排放特性的影响不大.     

ECD氧气诱导法分析大气中痕量HCFC-22

HCFC-22(CHClF₂)是CFC-12的主要替代物,它在大气中的体积分数仅为10^-12级.而且对ECD检测器响应灵敏度很低.本文经过低温浓缩进样后采用氧气诱导法来增强ECD对它的分析灵敏度,载气中氧气的体积分数为0.54%时,信噪比最大,此时ECD灵敏度增强约500倍.结合该条件下ECD温度选择、程序升温和载气流量的研究,建立了高灵敏度ECD气相色谱测定大气中HCFC-22浓度的实用分析方法.     

新冠肺炎疫情下的高校复课综合风险评估

为评估新冠肺炎疫情下的高校复课综合风险,辅助高校进行复课组织决策,探讨一种高校复课风险评估方法。首先,引入压力-状态-响应(PSR)模型,分析各要素互相影响机制,并建立高校复课新冠肺炎疫情综合风险评估指标体系;然后,利用风险的致灾因子与受灾体的脆弱性衡量疫情综合风险度,提出一种高校复课新冠疫情风险的评估方法;最后,以西安市某高校为例,验证风险评估模型的可行性和有效性。结果表明:本模型能准确评估高校复课新冠肺炎疫情综合风险;学校所在地疫情风险等级、人员管控措施、学校应急演练与评估开展状况分别是P、S、R系统的主要影响因素,应重点关注。     

中东部地区森林资源现状与问题分析

采用20世纪80-90年代的文献资料及调研数据,分析了我国中东部地区森林生态环境的现状.结果表明,我国中东部地区森林资源丰富,森林覆盖率明显提高,但存在分布不均,人均占有量低,结构不尽合理,生态功能低下等问题.为此,中东部地区应在提高森林面积的同时,继续加大天然林保护力度,不断提高森林质量;在管理和经营方面,要保护和利用结合,分类经营、分区管理.      

Carbon emissions from the peat fire problem—a review

Environmental Science and Pollution Research - Peat fires in tropical peatland release a substantial amount of carbon into the environment and cause significant harm to peatlands and the ecology,...     

Acceleration of the particulate organic matter hydrolysis by start-up stage recovery and its original microbial mechanism

• Carbon availability was partially solved by POM recovery and fermentation. • 12% carbon sources were regenerated by fermentation of the entrapped 35% TCOD. • The unique microbial communities facilitated the efficient hydrolysis of the POM. • Considerable economic benefits in aeration power and ECS dosage were anticipated. To address the availability of carbon sources for denitrification, the accelerated hydrolysis of the most abundant but low-availability fraction of particulate organic matter (POM) was investigated. Mesh sieves with different pore sizes were used as primary pretreatment at the start-up-stage of the biological process to separate some POM from the liquid system. The changes in soluble carbohydrates and proteins were monitored to investigate the hydrolysis performance of the sieved POM, with waste activated sludge (WAS) as the control test. The results showed that an average of 35% POM could be entrapped before filtrate mat development. In addition, benefiting from the high polysaccharides concentration, as well as the high availability due to the relatively loose physical structure, a 23% hydrolysis efficiency of POM was obtained, in contrast to that of WAS (3.4%), with a hydrolysis constant of 0.39 h⁻¹. The prominent performance was also attributed to the unique microbial communities having been domesticated at a lower temperature, especially the cellulose-degrading bacteria Paraclostridium and psychrophile Psychrobacter, making up 6.94% and 2.56%, respectively. Furthermore, the potential benefits and application of improved POM hydrolysis by start-up stage recovery via mesh sieves combined with anaerobic fermentation were evaluated, including selective POM entrapment, alleviation of blockage and wear, and a reduction in aeration energy. By the proposed strategy, carbon availability for biological nutrient removal (BNR) processes is anticipated to be improved more economically than that can be achieved by primary clarifier elimination.     

International mechanism for loss and damage from climate change: recommendations for related work in China

Loss and damage (L&D) from climate change has threatened the sustainable development of humankind, while the progress of mitigative and adaptive measures carried out under the international multilateral framework has been slow. The scientific community and policymakers have placed increasing emphasis on the international L&D response mechanism as a potential direct solution. This paper reviewed the origins of such a mechanism, with an in-depth analysis of the related connotations. A review of the existing situation in China on work related to L&D arising from climate change was conducted, followed by a summary of the findings. Finally, measures and recommendations to improve China’s efforts were proposed in this issue.     

黄河水环境特征与氮磷负荷时空分布

黄河是我国西北和华北地区重要的供水水源,由于地形和降雨等自然因素以及频繁的人类活动影响,黄河流域水环境问题日渐凸显.为明确黄河干流水环境特征、水质现状以及流域氮磷负荷时空分布,本研究于2019年的4～5月和10～11月对黄河干流全河段水环境进行了调查研究.基于野外采样研究结果以及室内实验数据,结果发现:①从源区至河口多个水体理化参数逐渐上升的趋势反映了越来越频繁的人类活动以及中下游水土流失等的共同作用,此外,水库对溶质的截留与沉积具有显著的效果;②两个季节水质差异较小,从源区至河口水质等级由"优秀"下降至"一般";③降雨是黄河流域氮磷赋存形态及其负荷具有季节性差异的关键因素;④黄河流域内氮磷赋存形态及其负荷所具有的空间差异性主要受控于人类活动与水土流失的影响.本研究结果可为控制黄河流域入河氮磷负荷以及改善水质提供科学依据.     

冬小麦田O3气孔与非气孔沉降及风险评估

为了深入了解农田生态系统的O_3干沉降过程,并基于O_3通量(尤其是气孔O_3累积通量)指标进行风险评估,利用涡度相关系统对冬小麦田的O_3干沉降过程进行了连续动态观测,初步分析O_3浓度和总O_3通量的变化过程,着重探析气孔O_3沉降和非气孔O_3沉降的变化特征及其与主要气象因子的关系,并基于剂量指标(AOT40)和通量指标(DF_s06)分别推算出冬小麦的产量损失率.结果表明,观测期间(自2016年3月16日至5月30日)日平均O_3浓度(cO_3)为32.9 n L·L-1;白天(08:00~18:00)和夜间平均总O_3通量(F_(O3))分别为-7.6 nmol·(m~2·s)~(-1)和-3.1 nmol·(m~2·s)~(-1),日均F_(O3)为-5.1nmol·(m~2·s)~(-1).逐日平均气孔O_3通量(F_s)的变化范围为0~-5.1 nmol·(m~2·s)~(-1),日均F_s为-1.43 nmol·(m~2·s)~(-1).逐日平均非气孔O_3通量(F_(ns))的变化范围为-1.43~-10.31 nmol·(m~2·s)~(-1),日均F_(ns)为-3.66 nmol·(m~2·s)~(-1).较强的太阳辐射(SR)、较高的温度(T)和适度湿润的条件有利于冬小麦气孔沉降;较强的SR、适度的T和湿润条件是有利于冬小麦非气孔沉降.在整个观测期间,总O_3累积吸收通量(DF_(O3))、气孔O_3累积吸收通量(DF_s)和非气孔O_3累积吸收通量(DF_(ns))分别为31.58、9.99和21.59 mmol·m~(-2),总DF_s和总DF_(ns)分别占总DF_(O3)的32%和68%.通过剂量指标AOT40和通量指标DF_s06响应方程计算出的冬小麦产量损失率分别为11.58%~20.37%和20%~23.56%.