Investigation of oxy-fuel combustion for methane and acid gas in a diffusion flame

Co-combustion of methane(CH4)and acid gas(AG)is required to sustain the temperature in Claus reaction furnace.In this study,oxy-fuel combustion of methane and acid gas has been experimentally studied in a diffusion flame.Three equivalence ratios(ER=1.0,1.5,2.0)and CH_(4)-addition ratios(CH_(4)/AG=0.3,0.5,0.7)were examined and the flame was interpreted by analyzing the distributions of the temperature and species concentration along central axial.CH_(4)-AG diffusion flame could be classified into three sections namely initial reaction,oxidation and complex reaction sections.Competitive oxidation of CH_(4)and H_(2)S was noted in the first section wherein H_(2)S was preferred and both were mainly proceeding decomposition and partial oxidation.SO_(2)was formed at oxidation section together with obvious presence of H2 and CO.However,H2 and CO were inclined to be sustained under fuel rich condition in the complex reaction section.Reducing ER and increasing CH4/AG contributed to higher temperature,H_(2)S and CH_(4)oxidation and CO_(2)reactivity.Hence a growing trend for CH_(4)and AG to convert into H_(2),CO and SO_(2)could be witnessed.And this factor enhanced the generation of CS2 and COS in the flame inner core by interactions of CH4 and CO_(2)with sulfur species.COS was formed through the interactions of CO and CO_(2)with sulfur species.The CS_(2)production directly relied on reaction of CH_(4)with sulfur species.The concentration of COS was greater than CS_(2)since CS_(2)was probably inhibited due to the presence of H_(2).COS and CS_(2)could be consumed by further oxidation or other complex reactions.

Naringin ameliorates acetic acid induced colitis through modulation of endogenous oxido-nitrosative balance and DNA damage in rats

The aim of this study was to evaluate the effect of naringin on experimentally induced inflammatory bowel dis- ease in rats. Naringin （20, 40 and 80 mg/kg） was given orally for 7 days to Wistar rats before induction of colitis by intrarectal instillation of 2 mL of 4% （v/v） acetic acid solution. The degree of colonic mucosal damage was analyzed by examining mucosal damage, ulcer area, ulcer index and stool consistency. Intrarectal administration of 4% acetic acid resulted in significant modulation of serum alkaline phosphatase, lactate dehydrogenase, superoxide dismutase （SOD）, glutathione （GSH）, malondialdehyde （MDA） and myeloperoxidase （MPO） content along with colonic nitric oxide （NO）, xanthine oxidase （XO） level and protein carbonyl content in the colonic tissue as well as in blood. Naringin （40 and 80 mg/kg） exerted a dose dependent （P 〈 0.05） ameliorative effect, as it significantly increased hematological parameter as well as colonic SOD and GSH. There was a significant （P 〈 0.05） and dose dependant inhibition of macroscopical score, ulcer area along with colonic MDA, MPO activity by the 7 days of pretreatment of naringin （40 and 80 mg/kg）. Biochemical studies revealed a significant （P 〈 0.05） dose dependant inhibition in serum alkaline phosphatase （ALP） and lactate dehydrogenase （LDH） levels by pretreatment of naringin. Increased levels of colonic NO, XO, protein carbonyl content and DNA damage were also sig- nificantly decreased by naringin pretreatment. The findings of the present investigation propose that naringin has an anti-inflammatory, anti-oxidant and anti-apoptotic potential effect at colorectal sites as it modulates the production and expression of oxidative mediators such as MDA, MPO, NO and XO, thus reducing DNA damage.

Quality, fatty acid composition and oxidation stability of ten cold-pressed seed oils

Cold-pressed oils from six herb plant seeds and four woody plant seeds were analyzed and compared for their quality characteristics such as oil, crud protein, shell, and moisture content, fatty acid （FA） compositions and oxidation stability. Results showed that walnut kernel contained the greatest amount of seed oil and safflower seed contained the lowest. Safflower, pumpkin, hemp, camellia and peony seeds had high shell content, their kernel oil content significantly increased after shelling. These oils had significant differences （p〈0.01） in levels of fatty acids and the ratio of n-6：n-3 fatty acids. Camellia, safflower, and flax seed oil contained the highest oleic acid, linoleic acid, and a-linolenic acid respectively. Hemp seed oil was observed in a 3.53：1 ratio of n-6 and n-3 fatty acids. All these ten oils were obviously different in moisture and volatile content, acid value, peroxide value and induction period （IP） （p〈0.01）. IP of peony seed oil was lowest （0.94 h） and almond oil was the highest （14.10 h）. IP of oils negatively correlated with polyunsaturated fatty acids content ^=-0.664, p=0.036）. These studies of ten cold-pressed oils may provide better explanation for their potential health benefits and further developing their commercial value.

带钢无酸除鳞专利分析

从专利角度出发,对带钢无酸除鳞专利申请趋势、主要申请人进行统计分析,对典型的带钢无酸除鳞专利技术进行了探讨,并对带钢无酸除鳞技术未来的发展方向进行了展望,可为无酸除鳞研发和技术应用提供参考。

6款市售狮子头的品质及风味分析

为明确现有市售狮子头产品的品质差异,本研究通过6款不同品牌(A1-口缘、A2-五亭桥、A3-琪津、A4-老扬城、A5-三珍斋、A6-黄珏)市售狮子头的感官、色泽、质构特性、失水率、脂肪氧化等理化指标综合分析市售狮子头的品质性状,结合游离脂肪酸和挥发性风味物质进行表征。结果表明,A1狮子头感官评分高达34分,6款市售狮子头中A4的红度值高达3.46±0.08,而A1的脂肪氧化值最低为0.44 mg MDA/kg,其中A5、A6的咀嚼性较低为0.21±0.02、0.32±0.11 mJ;6款市售狮子头以油酸为主,其次以棕榈酸、硬脂酸等饱和脂肪酸构成,狮子头中的多不饱和脂肪酸被大量氧化反应分解为醛类等物质,同时饱和脂肪酸含量明显提升。γ-松油烯、己醛、芳樟醇、壬醛等为其共有的挥发性风味物质,除此之外,A1主要关键挥发性风味物质为2-戊基呋喃,A2主要关键挥发性风味物质为巴伦西亚橘烯、甲基庚烯酮、异戊醛,而A4主要关键挥发性风味物质为辛酸乙酯,A5为4-萜烯醇、十一醇、甲硫醇、糠醇、糠醛、硬脂酸甲酯、茴香脑,A6则是十一醇、苯丙醛。因此烃类、醛类与醇类、酮类可能是影响不同市售狮子头产品风味品质的主要因素。该研究结果可为市售狮子头产品质量评价体系的构建以及风味统一与产品开发生产提供理论参考。

基于抗坏血酸调控氧化铈纳米酶催化活性的抗坏血酸氧化酶检测研究

纳米酶是一类既有纳米材料的独特性能又有催化功能的模拟酶,它既有天然酶的高催化活性,又有模拟酶稳定经济的特点,在生物传感检测领域的应用十分广泛。本研究采用水热法合成具有辣根过氧化物酶样活性的氧化铈纳米酶。该纳米氧化铈同时具有+4价和+3价两种形态,其中Ce^(4+)能与过氧化氢反应,使3,3’,5,5’-四甲基联苯胺(TMB)氧化,溶液显蓝色。由于抗坏血酸(AA)能还原Ce^(4+),抑制其催化活性以及TMB的氧化,从而使溶液的颜色较浅。而抗坏血酸氧化酶可催化氧化AA,阻碍了其对Ce^(4+)的还原,使纳米氧化铈的催化性能恢复。利用这种方法,实现对抗坏血酸氧化酶的定量检测,在12 U/L~400 U/L范围内呈良好的线性关系(R^(2)=0.9704),检测限为3.2 U/L。该研究为基于氧化铈纳米酶的比色方法在抗坏血酸氧化酶活性检测及相关应用提供基础。

纳米铁氧化物强化牛粪厌氧发酵产甲烷

为探究金属添加剂对牛粪厌氧发酵产甲烷过程的影响,提升牛粪厌氧发酵效率,本研究以纳米铁氧化物(Iron oxide nanoparticle,INP)为典型金属添加剂,比较了添加INP的反应器和从未添加INP的对照反应器中日产甲烷量、总挥发性酸、纤维素和半纤维素等的变化,并进一步探究INP添加对微生物群落和关键酶活性的影响。结果显示,INP添加促进纤维素水解并有利于挥发性脂肪酸的降解,从而促进产甲烷过程。连续反应器每日添加625 mg∙L^(-1)INP时日甲烷产量达到173.4 mL∙g^(-1)∙d^(-1),比对照组提高了38.3%;即使反应器停止添加INP,与对照组相比日产甲烷量依然显著提高(P<0.05)。16S rRNA分析表明,INP添加富集了乙酸氧化菌Mesotoga和嗜氢产甲烷菌Methanoculleus这一对协同互营菌。宏基因组分析表明,INP添加显著促进嗜乙酸产甲烷途径和嗜氢产甲烷途径相关酶的活性,尤其提高了甲烷合成关键酶-甲基辅酶M还原酶(EC 2.8.4.1)的活性(P<0.05),这是产甲烷效能提升的主要原因。综上,INP添加剂的施用有利于牛粪厌氧发酵产甲烷,从而提升畜禽粪污能源化利用效率。

Evaluation of the Protein Requirement in Chinese Young Adults Using the Indicator Amino Acid Oxidation Technique

Objective To accurately calculate the protein requirements in Chinese young adults using the indicator amino acid oxidation technique. Methods Nine women and ten men received a restricted daily level of protein intake （0.75, 0.82, 0.89, 0.97, and 1.05 g/kg）, along with L-[1-13C]-Ieucine. Subjects＇ protein requirement was determined by a biphasic linear regression crossover analysis of F13C02 data. In doing so, a breakpoint at the minimal rate of appearance of 13C02 expiration specific to each level of dietary protein was identified. This trial was registered with the Chinese clinical trial registry as ChiCTR-ONC-11001407. Results The Estimated Average Requirement （EAR） and the Recommended Nutrient Intake （RNI） of protein for healthy Chinese young adults were determined to be 0.87 and 0.98 g/（kg.d）, respectively, based on the indicator amino acid oxidation technique. Conclusion The EAR and RNI of mixed protein are 5% and 16% that are lower than the current proposed EAR and RNI {0.92 and 1.16 g/（kg.d）, respectively）, as determined by the nitrogen balance method. The respective EAR and RNI recommendations of 0.87 and 0.98 g/（kg.d） of mixed protein are estimated to be reasonable and suitable for Chinese young adults.

Characterization of Vegetable Oils by Fluorescence Spectroscopy

Results presented in this paper show the ability to analyze vegetable oils with very cheap and easy method based on fluorescence spectroscopy. We have recorded, with a very simple experimental set up, fluorescence spectra for several vegetable oils at excitation wavelength λex = 370 nm. After deconvolution, using a Lorentzian profile, and identification of the stripes forming the spectra, a normalization of the intensities was made with respect to the vitamin E band with λ= 525 nm taken as reference. A statistical method based on Principal Component Analysis (PCA) is used to emphasize differences between refined and unrefined oils. We also noticed a significant difference between fluorescence of the argan cosmetic oil and edible argan oil due to the heating of the second one during its preparation. Stability to thermal oxidation of high oleic sunflower oil compared to the extra virgin olive, argan cosmetic and refined corn oils is also shown.

Lactobacillus frumenti mediates energy production via fatty acid β-oxidation in the liver of early-weaned piglets

Background:Early-weaning of piglets is often accompanied by severe disorders,especially diarrhea.The gut microbiota and its metabolites play a critical role in the maintenance of the physiologic and metabolic homeostasis of the host.Our previous studies have demonstrated that oral administration of Lactobacillus frumenti improves epithelial barrier functions and confers diarrhea resistance in early-weaned piglets.However,the metabolic response to L.frumenti administration remains unclear.Then,we conducted simultaneous serum and hepatic metabolomic analyses in early-weaned piglets administered by L.frumenti or phosphatebuffered saline(PBS).Results:A total of 1006-day-old crossbred piglets(Landrace×Yorkshire)were randomly divided into two groups and piglets received PBS(sterile,2 m L)or L.frumenti(suspension in PBS,10~8 CFU/m L,2 m L)by oral administration once per day from 6 to 20 days of age.Piglets were weaned at 21 days of age.Serum and liver samples for metabolomic analyses were collected at 26 days of age.Principal components analysis(PCA)showed that L.frumenti altered metabolism in serum and liver.Numerous correlations(P<0.05)were identified among the serum and liver metabolites that were affected by L.frumenti.Concentrations of guanosine monophosphate(GMP),inosine monophosphate(IMP),and uric acid were higher in serum of L.frumenti administration piglets.Pathway analysis indicated that L.frumenti regulated fatty acid and amino acid metabolism in serum and liver.Concentrations of fatty acidβ-oxidation related metabolites in serum(such as3-hydroxybutyrylcarnitine,C4-OH)and liver(such as acetylcarnitine)were increased after L.frumenti administration.Conclusions:Our findings suggest that L.frumenti regulates lipid metabolism and amino acid metabolism in the liver of early-weaned piglets,where it promotes fatty acidβ-oxidation and energy production.High serum concentrations of nucleotide intermediates,which may be an alternative strategy to reduce the incidence of diarrhea in early-weaned piglets,were further detected.These findings broaden our understanding of the relationships between the gut microbiota and nutrient metabolism in the early-weaned piglets.

Anodic Coating Characteristics of Different Aluminum Alloys for Spacecraft Materials Applications

Anodic oxide coatings on aluminum alloys are used for space environment applications. These provide specific thermo-optical properties to spacecraft surface. Fragments of these coatings lead to generate the contamination in satellites and affect the mission lifetime. The current work concerns studying of the anodic processes applied on aluminum and different groups of aluminum alloys as Al7075, Al2024 and Al6061. Experimental procedures are performed using sulfuric acid at different values of current density (1 - 2 A/dm2). The influence of the parameters of anodic film formation on the coating characteristics and layer thickness of aluminum alloys has been investigated. Reflectance and optical properties of the anodized aluminum alloy coatings are determined and found to be dependent on the alloying elements. Changes in anodic coating weight and film thickness of aluminium alloys with the process parameters as current density, temperature, time duration, acid concentration, and sealing system have been studied. Moreover, morphology and surface structure of the considered samples are carried out in attempt to understand the physical characteristics. The obtained results are compared and briefly outlined.

基于转录组分析植物乳杆菌AR195在亚油酸胁迫下的生理响应

植物乳杆菌(Lactiplantibacillus plantarum)和共轭亚油酸(CLA,Conjugated linoleic acid)均具有良好的益生特性和保健功能。目前人们已经明确了植物乳杆菌CLA生物合成的途径,但仍然缺乏对底物亚油酸(Linoleic acid,LA)响应机制的研究。文章基于转录组学分析了LA对植物乳杆菌AR195生长和基因表达的影响,结果表明LA能够抑制AR195的生长,添加LA后AR195中157个基因上调,67个基因下调,差异表达基因在代谢、环境信息处理和细胞过程等KEGG通路中富集。LA毒性主要来自于生长抑制和氧化还原失衡,而AR195可通过维持氧化还原平衡、生物转化CLA、增强碳源摄取及代谢、全局转录调控等生理响应过程缓解LA毒性。文章首次提出植物乳杆菌AR195应对LA胁迫的分子机制,为植物乳杆菌对LA的应激响应及CLA合成的内在动因提供了新的见解。

共存阳离子对含锰酸性矿山废水化学中和处理过程的影响

文章采用化学中和法处理模拟酸性矿山废水(acidminedrainage,AMD),探究共存离子Fe^(2+)、Mg^(2+)和Al^(3+)在曝气搅拌和机械搅拌2种条件下对锰的去除率及其固相产物的影响.结果表明:3种共存离子对锰的去除均具有一定的促进作用;其中Al^(3+)的作用最显著,但Al^(3+)及其产物对锰离子的氧化有抑制作用;Al^(3+)、Fe^(2+)的存在会降低固相产物中锰元素的质量比并影响沉积物组成,不利于后续回收处理.研究结果可为化学中和除锰工艺优化及固相产物回收利用研究提供参考.

高单不饱和脂肪酸液体鼻饲对急性脑卒中取栓术后患者糖脂代谢影响的动态分析

目的 动态分析高单不饱和脂肪酸液体鼻饲对急性脑卒中取栓术后患者糖脂代谢的影响。方法 纳入2021年1月至2022年9月上海市第六人民医院100例脑卒中取栓术后患者为研究对象,采用随机数字表法随机分为对照组和干预组,每组50例。对照组采用传统鼻饲方案进行肠内营养支持治疗,干预组予以高单不饱和脂肪酸液体鼻饲喂养。动态监测两组糖脂代谢指标,分析高单不饱和脂肪酸液体饮食对急性脑卒中患者糖脂代谢影响,并比较两组患者营养指标、氧化应激指标及不良反应。结果 两组第1个24 h血糖及胆固醇变异系数比较差异无统计学意义(P>0.05),第2个24 h及第3个24 h血糖及胆固醇变异系数干预组低于对照组(P<0.05);鼻饲结束后,两组内皮型一氧化氮合酶(eNOS)、丙二醛(MDA)、超氧化物歧化酶(SOD)水平均改善,且干预组MDA水平低于对照组,eNOS、SOD水平高于对照组(P<0.05);两组不良反应发生率比较差异无统计学意义(P>0.05)。结论 高单不饱和脂肪酸液体鼻饲可为急性脑卒中取栓术后患者提供营养,并可有效维持糖脂代谢平衡,降低患者应激反应,且不增加患者不良反应发生率。

基于经济性分析的铜钴氧化矿浸出条件优化

针对铜钴矿浸出过程,单一强化控制参数,虽然可以提升铜、钴浸出率,但是也会相应造成浸出液游离酸偏高、杂质的超量溶出及辅料消耗增加等问题,经济效益并非最佳。针对某低品位氧化铜钴矿硫酸体系铜、钴浸出过程,考察了矿石粒度、浸出酸量、SO_(2)用量、液固比、浸出时间等对有价金属Cu、Co及杂质Fe、Mn、Si浸出的影响规律。在对单因素强化浸出措施进行经济效益分析的基础上,最终确定了适宜的工艺参数条件:磨矿时间5 min、终点pH值在1.5左右、吨矿SO_(2)用量6.37 kg、液固比3∶1(mL/g)、浸出时间5 h。在该条件下,Cu、Co的浸出率分别为93.67%和75.90%,Mn的浸出率约为87.00%,Fe和Si的浸出率分别为2.66%和0.24%。

不同干燥条件对风干牛肉品质影响

为提高风干牛肉的干燥效率,明确干燥条件对风干牛肉品质的影响,以牛肉为研究对象,通过常规方式和高温短时干燥处理方式[对照组(15℃,7 d)、A组(50℃,30 h)、B组(55℃,27 h)、C组(60℃,24 h)、D组(65℃,21 h)]对其进行风干,分析不同处理对牛肉水分含量、水分活度、剪切力、蛋白质氧化、硫代巴比妥酸反应物(thiobarbituric acid reactive substances,TBARS)值、游离氨基酸含量、风味成分变化及感官评分的影响。结果表明,高温短时干燥对风干牛肉水分含量和水分活度影响不显著(p>0.05),对牛肉剪切力影响显著(p<0.05)。风干牛肉脂肪氧化和蛋白质的氧化、水解随着风干温度升高而增加。风干结束后,5组样品中TBARS值最高为1.18 mg MDA/kg,羰基含量为4.66 mmol/mg蛋白;风干牛肉游离氨基酸总量B组最高,为628.88 mg/100 g。气相色谱-离子迁移谱(gas chromatography ion mobility spectrometry,GC-IMS)结果显示,B组样品主要的挥发性风味物质最为丰富,且与其他4组差异最大,主要的特征风味物质为丁酸丙酯、丙二酸二乙酯、辛酸乙酯、丙酸异丁酯、乙酸甲酯、乙酸正己酯、乙酸辛酯等;适当提高干燥温度可以明显改善风干牛肉的色泽、风味和组织状态的评分。综合各项指标,风干温度55℃、风干时间27 h处理的风干牛肉品质最佳。

获取优良分散性炭黑的表面硝酸氧化

为得到具有良好分散性的炭黑,考察其表面的化学性质,利用硝酸长时间氧化,用沉降度检测炭黑的分散性,并利用红外光谱、X射线光电子能谱及激光粒度仪检测其表面的物化性质.研究表明:硝酸氧化增加了炭黑的表面含氧量及炭黑的酸性,使炭黑的分散性得到了极大的提高;硝酸氧化在炭黑表面引进了羧基基团和羟基基团.

乙二醛阳极氧化制乙醛酸过程的化学分析方法

乙二醛阳极氧化制乙醛酸的电解液可用简便的化学分析法测定 ,其中草酸的定量可用钙盐沉淀后用高锰酸钾法测定 ;乙二醛的定量用坎尼查罗反应后用标准酸测定 ;醛总量用亚硫酸钠法测定 ,乙醛酸的定量用醛总量减乙二醛的量。

核桃油中脂肪酸和内源抗氧化物质含量及其氧化稳定性相关性分析

以8个核桃品种为研究对象,有机溶剂萃取法提油,测定核桃油内源性组分（脂肪酸和内源抗氧化物质）和氧化稳定性（OSI）并对其进行相关性分析。结果表明：核桃油以不饱和脂肪酸（USFA）为主,其中以亚油酸含量最高,油酸/亚油酸比值（O/L）在0.3~0.5内;3种VE异构体按含量高低排序γ-VE〉δ-VE〉α-VE;甾醇含量由高到低排序为β-谷甾醇〉菜油甾醇〉豆甾醇;相关关系中,油酸和O/L与氧化稳定性呈极显著正相关（P〈0.01,r1=0.742 1,r2=0.859 5）,亚油酸和多不饱和脂肪酸（PUFA）与氧化稳定性都呈极显著负相关（P〈0.01,r1=-0.845 7,r2=-0.901 1）;核桃油氧化稳定性主要受脂肪酸影响（尤其是O/L）,其内源性抗氧化物质与油氧化稳定性并未呈现显著的相关关系。通过对比结果显示,新疆品种新巨丰榨取的核桃油氧化稳定性最高,相应O/L最低,适于长货架期的核桃油加工。该结果将对核桃油氧化稳定性评价以及适宜制油核桃品种筛选提供一定的指导。

抗氧化乳酸菌对发酵腌干带鱼脂肪氧化的影响及其主成分分析

将从传统腌干鱼中筛选出的3株具有抗氧化活性乳酸菌(干酪乳杆菌、植物乳杆菌和戊糖片球菌)作为发酵剂加入到腌干带鱼中,测定pH值、过氧化值、酸值、硫代巴比妥酸值和正己醛含量等指标,以监测发酵腌干带鱼加工过程中脂肪的氧化程度,并分析了乳酸菌发酵对腌干带鱼成品脂肪酸组成的影响。结果表明,在腌干带鱼生产过程中抗氧化乳酸菌对不饱和脂肪酸的氧化有一定的抑制作用,接菌发酵的腌干带鱼过氧化值、硫代巴比妥酸值、正己醛含量和饱和脂肪酸含量显著低于传统腌干带鱼,而酸值和不饱和脂肪酸含量高于传统腌干带鱼。对测定的指标进行主成分分析的结果表明,第1主成分能反映脂肪水解程度,其线性回归函数为:Y_1=0.131X_1+0.208X_2+0.360X_3+0.244X_4+0.083X_5-0.388X_6+0.324X_7+0.343X_8;第2主成分能反映脂肪氧化程度,其线性回归函数为:Y_2=0.330X_1+0.406X_2+0.182X_3+0.440X_4+0.294X_5-0.205X_6+0.135X_7+0.157X_8。本研究为提高发酵腌干鱼的安全性提供理论依据。