Identification of Odor Volatile Compounds and Deodorization ofPaphia undulata Enzymatic Hydrolysate

Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase mi- croextraction gas chromatography mass spectrometry （HS-SPME-GC-MS） analysis of volatiles from untreated samples and three deodorized samples （under the optimal conditions） ofPaphia undulata enzymatic hydrolysate revealed that the compounds contrib- uting to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodoriz- ing effects of activated carbon （AC） adsorption, yeast extract （YE） masking and tea polyphenol （TP） treatment on a P. undulata en- zymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained： AC adsorption （35 mg mL-1, 80℃, 40 rain）, YE masking （7 mgmL l, 45 ℃, 30 min） and TP treatment （0.4mgmL-l, 40℃, 50min）. AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of alde- hydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine （TMA） formation in a P. un- dulate hydrolysate solution for a period of 72 h.

Study on contrast test of PPC pre-oxidation and coagulation for algae removal and deodorization

The effect of treating algae-bearing water and induced odor by use of permanganate potassium composite （PPC） pre-oxidation was investigated, and was compared with the effect of treatments by pre-chlorination, permanganate petassium pre-oxidation and simple coagulation. The results showed that simple coagulation and pre-chlorination were less effective in removing algae and its odor, whereas PPC pre-oxidation was the most effective in algae removal and deodorization. Upon oxidation with PPC, the cells of Oscillatoria agardhic were inactivated and some intra-cellular and extra-cellular components were released into the water, which may help the coagulation by their bridging effect. The efficient removal of algae by PPC pre-oxidation is believed to be the joint contribution of several mechanisms.

Comparison and Analysis of Fabric Deodorization Test Methods

The test methods of deodorization fabric are studied in daily life. In view of different deodorization fabrics and source gases,the detector tube method and gas chromatography-flame ionization detector ( GC-FID ) method were chosen to test the deodorizing rates of fabric and the influencing factors on deodorization test were discussed. Through the two methods,the residual concentration of odorous substance after adsorption can be measured,and the deodorizing rates of deodorization fabric can be got by calculation. The results show that the two test methods are both appropriate for deodorization test of fabric.

Two-Stage Approach for Targeted Knowledge Transfer in Self-Knowledge Distillation

Knowledge distillation(KD) enhances student network generalization by transferring dark knowledge from a complex teacher network. To optimize computational expenditure and memory utilization, self-knowledge distillation(SKD) extracts dark knowledge from the model itself rather than an external teacher network. However, previous SKD methods performed distillation indiscriminately on full datasets, overlooking the analysis of representative samples. In this work, we present a novel two-stage approach to providing targeted knowledge on specific samples, named two-stage approach self-knowledge distillation(TOAST). We first soften the hard targets using class medoids generated based on logit vectors per class. Then, we iteratively distill the under-trained data with past predictions of half the batch size. The two-stage knowledge is linearly combined, efficiently enhancing model performance. Extensive experiments conducted on five backbone architectures show our method is model-agnostic and achieves the best generalization performance.Besides, TOAST is strongly compatible with existing augmentation-based regularization methods. Our method also obtains a speedup of up to 2.95x compared with a recent state-of-the-art method.

Two-Stage Optimal Scheduling of Community Integrated Energy System

From the perspective of a community energy operator,a two-stage optimal scheduling model of a community integrated energy system is proposed by integrating information on controllable loads.The day-ahead scheduling analyzes whether various controllable loads participate in the optimization and investigates the impact of their responses on the operating economy of the community integrated energy system(IES)before and after;the intra-day scheduling proposes a two-stage rolling optimization model based on the day-ahead scheduling scheme,taking into account the fluctuation of wind turbine output and load within a short period of time and according to the different response rates of heat and cooling power,and solves the adjusted output of each controllable device.The simulation results show that the optimal scheduling of controllable loads effectively reduces the comprehensive operating costs of community IES;the two-stage optimal scheduling model can meet the energy demand of customers while effectively and timely suppressing the random fluctuations on both sides of the source and load during the intra-day stage,realizing the economic and smooth operation of IES.

Solar-assisted two-stage catalytic membrane reactor for coupling CO_(2) splitting with methane oxidation reaction

A two-stage catalytic membrane reactor(CMR)that couples CO_(2) splitting with methane oxidation reactions was constructed based on an oxygen-permeable perovskite asymmetric membrane.The asymmetric membrane comprises a dense SrFe_(0.9)Ta_(0.1)O_(3-σ)(SFT)separation layer and a porous Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Cu_(0.1)O_(3-σ)(SFTC)catalytic layer.In thefirst stage reactor,a CO_(2) splitting reaction(CDS:2CO_(2)→2CO+O_(2))occurs at the SFTC catalytic layer.Subsequently,the O_(2) product is selectively extracted through the SFT separation layer to the permeated side for the methane combustion reaction(MCR),which provides an extremely low oxygen partial pressure to enhance the oxygen extraction.In the second stage,a Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Ni_(0.1)O_(3-σ)(SFTN)catalyst is employed to reform the products derived from MCR.The two-stage CMR design results in a remarkable 35.4%CO_(2) conversion for CDS at 900℃.The two-stage CMR was extended to a hollowfiber configuration combining with solar irradiation.The solar-assisted two-stage CMR can operate stably for over 50 h with a high hydrogen yield of 18.1 mL min^(-1) cm^(-2).These results provide a novel strategy for reducing CO_(2) emissions,suggesting potential avenues for the design of the high-performance CMRs and catalysts based on perovskite oxides in the future.

Preparation and Application of Natural Bactericidal Deodorizer

Jasmine essential oil and lemon essential oil were selected for deodorizing ingredient.Lysine and silver ions were selected as auxiliary raw material.The product was prepared by emulsion dissolution technology.The minimum inhibitory concentration of various bacteria were during 100~2,000 mg/L.In the test,the germicidal efficiency of 2.0%(w/w)deodorant was 99%.The removal efficiency of trimethylamine and methanthiol were more than 95%by 3.0%(w/w).deodorant.The removal efficiency of ammonia and methanthiol were more than 92%by 3.0%(w/w)deodorant.In addition,The removal efficiency of isovaleric acid was 98%by 2.0%(w/w)deodorant.In analysis result,common pathogenic bacteria were effectively suppressed,kitchen and toilet odors were efficiently removed by natural plant deodorant.

Two-Stage Planning of Distributed Power Supply and Energy Storage Capacity Considering Hierarchical Partition Control of Distribution Network with Source-Load-Storage

Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning.

An interacting multiple model-based two-stage Kalman filter for vehicle positioning

To address the problem that a general augmented state Kalman filter or a two-stage Kalman filter cannot achieve satisfactory positioning performance when facing uncertain noise of the micro-electro-mechanical system（MEMS） inertial sensors, a novel interacting multiple model-based two-stage Kalman filter（IMM-TSKF） is proposed to adapt to the uncertain inertial sensor noise. Three bias filters are developed based on different noise characteristics to cover a wide range of noise levels. Then, an accurate estimation of biases is calculated by the interacting multiple model algorithm to correct the bias-free filter. Thus, the vehicle positioning system can achieve good performance when suffering from uncertain inertial sensor noise. The experimental results indicate that the average position error of the proposed IMMTSKF is 25% lower than that of the general TSKF.

Production of Light Olefins from Biosyngas by Two-stage Catalytic Conversion Process via Dimethyl Ether

NiSAPO-34 and NiSAPO-34/HZSM-5 were prepared and evaluated for the performance of dimethyl ether （DME） conversion to light olefins （DTO）. The processes of two-stage light olefin production, DME synthesis and the following DTO, were also investigated using biosyngas as feed gas over Cu/Zn/A1/HZSM-5 and the optimized 2%NiSAPO-34/HZSM- 5. The results indicated that adding 2%Ni to SAPO-34 did not change its topology structure, but resulted in the forming of the moderately strong acidity with decreasing acid amounts, which slightly enhanced DME conversion activity and C2=-C3= selectiw ity. Mechanically mixing 2%NiSAPO-34 with HZSM-5 at the weight ratio of 3.0 further prolonged DME conversion activity to be more than 3 h, which was due to the stable acid sites from HZSM-5. The highest selectivity to light olefins of 90.8% was achieved at 2 h time on stream. The application of the optimized 2%NiSAPO-34/HZSM-5 in the second-stage reactor for DTO reaction showed that the catalytic activity was steady for more than 5 h and light olefin yield was as high as 84.6 g/m3syngas when the biosyngas （H2/CO/CO2/N2/CH4=41.5/26.9/14.2/14.6/2.89, vol%） with low H/C ratio of 1.0 was used as feed gas.

氨同化细菌Acinetobacter sp.Z1在污泥堆肥过程中除臭保氮潜力的影响因素研究

针对污泥堆肥过程排放氨气等臭气并导致堆肥产物氮素损失的问题,对氨同化细菌Acinetobacter sp.Z1在污泥堆肥不同pH值、C/N、温度环境下基于同化作用减少氨气排放和氮储存的潜力进行了研究。在pH值为5~9、C/N为25~35、温度为20~50℃的环境范围,随着pH值、C/N、温度的升高,菌株Z1的NH4+-N去除能力增加,且pH值为9、C/N为30、温度为40℃时同化作用最强。表明菌株Z1可以适应污泥堆肥环境,且在高温氨气挥发最严重时发挥最佳效果,有利于帮助实现污泥堆肥过程氨气减排和氮素保留。

植物油脱臭馏出物中富集亚油酸甲酯的工艺开发

本文以各类脱臭馏出物(DD油)提取天然维生素E过程中副产的脂肪酸甲酯为原料,首先利用气相色谱结合理化分析,筛选葵花DD油来源的脂肪酸甲酯为后续研究原料,然后使用间歇精馏工艺,探讨了不同的真空度和回流比对亚油酸甲酯分离效果的影响,最后通过尿素络合进一步提纯亚油酸甲酯。结果表明:通过精馏工艺可以将原料中的亚油酸含量从52.6%富集到62.8%,最高为64.7%;然后以富集后的亚油酸甲酯为原料,在甲酯∶尿素∶95%乙醇=1∶2∶7(w/w/v),络合温度20℃,络合时间4 h的条件下,通过络合工艺将亚油酸甲酯的含量从62.8%进一步提高到85.3%,达到了较好的分离效果,为后续亚油酸及其酯的高值化利用打下坚实的基础。

基于GC-MS技术分析金钱白花蛇蛇油不同脱腥方法差异

目的对比研究不同脱腥方法对金钱白花蛇蛇油的脱腥效果。方法采用水蒸气蒸馏、活性炭吸附、氧化脱腥法脱腥处理蛇油,对三种脱腥方法进行单因素试验优化,感官评价各方法的脱腥效果;通过气质联用(GC-MS)法检测各脱腥法脱腥前后蛇油的脂肪酸成分,采用顶空固相微萃取-气质联用(HS-SPME-GC-MS)分析各脱腥方法脱腥前后蛇油的挥发性成分,采用分层聚类分析(HCA)、主成分分析(PCA)对脂肪酸成分进行分析,采用气味活度值法(OAV)评价各挥发性成分对气味的贡献。结果腥味脱除效果:水蒸气蒸馏法>氧化脱腥法>活性炭吸附法,水蒸气蒸馏法脱腥后脂肪酸成分构成最接近脱腥前。结论水蒸气蒸馏法对金钱白花蛇蛇油影响最小,脱腥效果最优,建立的分析方法可为金钱白花蛇蛇油开发利用提供参考。

生活垃圾渗滤液处理厂恶臭异味的产生与控制

以华东地区某生活垃圾渗滤液处理厂为例,检测分析了点源引起恶臭异味的主要致臭物质,结合工程案例提出了恶臭气体分块处理的方案,还介绍了除臭工艺的选择、除臭设备设计的相关参数以及项目运维过程中遇到的问题和解决方法。除臭设备稳定运行后,对除臭系统的排放口进行了连续跟踪检测,检测结果表明:除臭系统排放口硫化氢排放速率、氨排放速率、臭气浓度均低于《恶臭污染物排放标准(征求意见稿)》(GB 14554—2022)规定的限值(0.06 kg/h、2.4 kg/h、1500)。

大黄鱼预制调理产品工艺优化及保鲜技术研究

为探索大黄鱼调理制品的最佳制作工艺和不同包装方式对其贮藏品质的影响,以‘甬岱1号’大黄鱼为原料,采用湿腌方式进行腌制,在单因素试验结果的基础上,通过响应面法优化腌制、脱腥工艺,同时以菌落总数、pH、质构、总挥发性盐基氮(TVB-N)为指标,进一步探究不同包装方式(真空、气调75%CO_(2)/25%N_(2))对大黄鱼冷藏品质的影响。结果表明:最佳腌制、脱腥工艺为3%盐、10 g/L蒜汁、12 g/L姜汁和12 g/L料酒,腌制3 h,预测感官评分为83.73分,与验证结果(82.71分)接近;气相色谱-离子迁移谱联用仪(GC-IMS)检测出43种挥发性成分,脱腥后醇类、醛类等物质含量下降,鱼腥味减少。真空、气调可有效延缓冷藏期间微生物、pH、硬度、弹性和TVB-N品质指标的劣变速率,货架期分别延长了2 d和6 d。通过研究获得了咸度适中、腥味低且冷藏货架期长的大黄鱼调理制品,可为大黄鱼调理制品市场化提供理论支撑。

海参粉超临界CO_(2)萃取脱脂工艺优化及对挥发性风味物质的影响

本实验以海参粉为原料,以脱脂率为指标,采用单因素与正交试验优化了超临界CO_(2)萃取分离条件,通过气相色谱法检测萃取前后海参粉和萃取物中脂肪酸的组成变化,以顶空-气相色谱-离子迁移谱(HS-GC-IMS)考察超临界CO_(2)萃取对挥发性风味物质的影响。结果表明:采用单因素与正交试验优化后得出超临界CO_(2)萃取的最佳条件为:萃取温度60℃、萃取压力40 MPa、萃取时间2 h,在此条件下脱脂率为57.6%±3.89%;海参粉、萃取后海参粉和萃取物中共检测出25种脂肪酸,其中萃取物中单不饱和脂肪酸含量占比明显较高,而花生四烯酸(ARA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)等多不饱和脂肪酸含量在萃取后海参粉中占比更高;HS-GC-IMS定性检测到70种挥发性成分,萃取后海参粉中呈腥味或刺激性气味物质如二甲基硫醚、丁醛、反-2-丁烯醛、戊醛、庚醛、苯甲醛、戊醇、2-丁酮、2-己酮、3-己酮等物质含量比原料中含量明显减少,整体风味得到很大改善。因此,超临界CO_(2)萃取能够有效萃取分离出海参粉中脂类物质,同时去除大量腥味等挥发性成分。

舍内雾化喷洒生物除臭剂工艺在不同清粪工艺猪舍的除臭效果研究

试验旨在研究舍内雾化喷洒生物除臭剂在水泡粪工艺和干清粪工艺猪舍内的除臭效果。分别在句容市某水泡粪工艺育肥场和长兴县某干清粪工艺育肥场开展相关试验,2次试验使用同种生物除臭剂产品,每次试验共10 d时间,第5天开始使用除臭剂,并选取第2~4天作为对照组,第5~9天作为试验组。试验组每天人工在猪舍内喷洒2次、每次喷洒6 L,试验过程中持续监测舍内氨气(NH_(3))、硫化氢(H_(2)S)浓度变化。结果表明:水泡粪工艺猪舍在使用除臭剂处理3 d后,NH_(3)、H_(2)S浓度达到最低值,分别为2.24 mg/kg和0.11 mg/kg,此时的去除率为73.08%和72.50%,相比对照组极显著降低(P<0.01);干清粪工艺猪舍在使用除臭剂处理5 d后,NH_(3)浓度达到最低值,为5.22 mg/kg,去除率为52.65%,处理2 d后H_(2)S浓度达到最低值,为0 mg/kg,去除率为100%,均比对照组极显著降低(P<0.01)。试验结果说明舍内喷洒生物除臭剂对水泡粪和干清粪工艺猪舍内的NH_(3)、H_(2)S浓度均有明显去除效果。

基于Two-stage DEA-Tobit模型的中国省际竞技体育效率研究

基于Two-stage DEA的网络结构DEA方法,对我国31个省(直辖市、自治区)在第十二届全运会上的表现进行更深入的效率评价,并结合Tobit回归模型对影响竞技体育效率的社会环境因素进行分析.结果表明,全运会两个阶段中,仅山东省和西藏自治区为DEA有效的,AP阶段和AC阶段为DEA有效的地区分别为10个和3个,且提高各地区总效率的关键在于提高其AC阶段效率.从影响因素来看,地区经济水平与效率间存在负向影响,而体育场地资源配置及体育类支出是影响效率的主要因素,国民体质综合指数和体育投入规模对其无显著影响.

Advanced landfill leachate treatment using a two-stage UASB-SBR system at low temperature

A two-stage upflow anaerobic sludge blanket （UASB） and sequencing batch reactor （SBR） system was introduced to treat landfill leachate for advanced removal of COD and nitrogen at low temperature. In order to improve the total nitrogen （TN） removal efficiency and to reduce the COD requirement for denitrification, the raw leachate with recycled SBR nitrification supematant was pumped into the first-stage UASB （UASB1） to achieve simultaneous denitrification and methanogenesis. The results showed that UASB1 played an important role in COD removal and UASB2 and SBR further enhanced the nutrient removal efficiency. When the organic loading rates of UASB1, UASB2 and SBR were 11.95, 1.63 and 1.29 kg COD/（m^3.day）, respectively, the total COD removal efficiency of the whole system reached 96.7%. The SBR acted as the real undertaker for NH4^＋-N removal due to aerobic nitrification. The system obtained about 99.7% of NH4^＋-N removal efficiency at relatively low temperature （14.9-10.9℃）. More than 98.3% TN was removed through complete denitrification in UASB 1 and SBR. In addition, temperature had a significant effect on the rates of nitrification and denitrification rather than the removal of TN and NH4^＋-N once the complete nitrification and denitrification were achieved.

Multi-objective optimization for leaching process using improved two-stage guide PSO algorithm

A mathematical mechanism model was proposed for the description and analysis of the heat-stirring-acid leaching process.The model is proved to be effective by experiment.Afterwards,the leaching problem was formulated as a constrained multi-objective optimization problem based on the mechanism model.A two-stage guide multi-objective particle swarm optimization(TSG-MOPSO) algorithm was proposed to solve this optimization problem,which can accelerate the convergence and guarantee the diversity of pareto-optimal front set as well.Computational experiment was conducted to compare the solution by the proposed algorithm with SIGMA-MOPSO by solving the model and with the manual solution in practice.The results indicate that the proposed algorithm shows better performance than SIGMA-MOPSO,and can improve the current manual solutions significantly.The improvements of production time and economic benefit compared with manual solutions are 10.5% and 7.3%,respectively.