膜蒸馏浓缩纤维素糖液与去除糠醛的研究

研究了采用低能耗的真空膜蒸馏技术浓缩纤维素糖液,去除其中糠醛,提高木质纤维素产乙醇效率的可行性.通过考察料液流速、料液温度、料液浓度等对膜通量和糠醛去除率的影响,优化真实酶解糖液的膜蒸馏浓缩参数,并将浓缩糖液用于发酵.结果表明:在进料流速为1.0 m/s,进料温度为65℃下,膜蒸馏对葡萄糖的截留率在99.5％以上,糠醛去除率达到95.16％.真实酶解糖液浓缩和发酵实验表明,真空膜蒸馏可有效地浓缩酶解液至适合的发酵浓度(＞100 g/L)同时完全脱除抑制物糠醛,提高乙醇的发酵效率.     

厌氧发酵产氢系统的启动与乙醇型发酵优势菌群的建立

针对乙醇型发酵这一具有较高产氢能力的有机废水产酸发酵类型,通过小试模型实验和中试系统的运行实验,研究了发酵生物制氢污泥反应系统的启动规律和驯化乙醇型发酵优势菌群的对策。研究表明,厌氧活性污泥和好氧活性污泥都可作为发酵生物制氢污泥反应系统启动的种泥,在接种量不低于6．5gVSS／L,进水有机物浓度3000～5000gCOD／L,pH4．0～4．6,HRT8～11h等控制条件下,反应系统可在45d左右建立起乙醇型发酵菌群的优势地位,发酵气体中的氢气含量达到40％～50％。     

细胞对硅橡胶复合膜渗透蒸发分离性能的影响

利用自制的硅橡胶复合膜对乙醇-水模型溶液、含有干酵母的乙醇-水模型溶液、以及实际发酵液进行渗透蒸发分离乙醇实验,研究了细胞对膜性能的影响、结果表明：与纯乙醇模型溶液的分离相比,膜对含有干酵母的乙醇-水模型溶液、真实发酵液的分离表现出更好的性能,显示细胞的存在和活动对膜传质有一定的促进作用．连续发酵过程中,在一定的细胞浓度下（10g／L）,硅橡胶膜维持了长期稳定的分离性能;产品乙醇的有效分离降低了其对酵母细胞的抑制作用,使沉积在膜面上的细胞层促进了膜的分离性能;但提高细胞浓度（15g／L）后却因更厚的细胞层的堆积造成膜面传递状况劣化,使膜性能下降．因此发酵液中的细胞浓度、膜面上的细胞沉积以及膜性能之间存在一种最佳的相互促进和搭配关系．     

以PSA-A乳胶粒为模板批量制备TiO2空心球

以表面富载马来酸羧基的聚(苯乙烯-丙烯酸酯)阴离子(PSA-A)乳胶粒为模板,硫酸钛为原料,水为分散介质,制备了PSA-A/钛水解产物核壳微球,然后在空气中适当温度下煅烧得到粒径约为450nm的TiO2空心球壳,用TG、SEM、TEM、IR和XRD对样品进行了分析表征,并研究了核壳结构形成的过程和各实验条件对陈化过程中体系pH值变化速率的影响.得出影响核壳结构的关键因素为体系的pH值变化速率,以此依据设计出钛盐浓度为1mol/L,乳胶粒浓度为230g/L的高浓度条件下批量制备TiO2空心球壳的新实验方案,最终产物保持良好的空心球结构.     

恩施矿区煤矸石中白炭黑的提取试验

以恩施矿区煤矸石为原料,经煅烧活化、碱熔和乙醇的作用,最后酸中和等工艺过程,制得非晶态、纳米白炭黑。考察了煤矸石煅烧活化温度、NaOH用量、碱熔时间、乙醇浓度和盐析pH值对白炭黑溶出率的影响,并利用X-射线粉末衍射仪、傅里叶红外光谱仪和扫描电子显微镜对煤矸石和白炭黑进行了表征。结果表明,当煤矸石煅烧活化温度为720℃、NaOH用量为煤矸石用量的40%、碱熔时间为2h、乙醇浓度为2mol/L和盐析pH值为9时,白炭黑的溶出率较好,达到90.1%。     

羰基还原酶基因工程菌产酶和不对称合成(R)-苯乙醇的条件优化

以羰基还原酶基因工程菌全细胞为催化剂,探讨不对称合成(R)-苯乙醇的各种影响因素,优化其产酶和转化条件。结果表明,优化后的发酵培养基为甘油10 g/L、蛋白胨10 g/L、酵母粉5 g/L,(NH_4)_2SO_4 5 g/L、NaCl 10 g/L,氨苄青霉素50μg/mL,pH 7.2;诱导剂IPTG的浓度为0.25 mmol/L,诱导时间为20 h,诱导温度为18℃,此条件下测得基因工程菌粗酶活最高为6.65 U/mL。建立的最佳转化条件:羰基还原酶基因工程菌发酵20 h后的细胞浓度为0.3 g/mL,转化体系初始pH为7.0,温度为37℃,辅助底物异丙醇浓度为10%,底物终浓度为60 mmol/L,转化时间为24 h。此时底物转化率最高可达98.88%,产物对映体过量值(e.e.值)为99.43%。反应体系扩增至3 000 mL后,产物e.e.值仍保持在99.0%左右,底物转化率可为92%以上,(R)-苯乙醇的产量也可达到6.67 g/L。     

以PSA-A乳胶粒为模板批量制备TiO2空心球

以表面富载马来酸羧基的聚（苯乙烯-丙烯酸酯）阴离子（PSA-A）乳胶粒为模板,硫酸钛为原料,水为分散介质,制备了PSA-A/钛水解产物核壳微球,然后在空气中适当温度下煅烧得到粒径约为450nm的TiO2空心球壳,用TG、SEM、TEM、IR和XRD对样品进行了分析表征,并研究了核壳结构形成的过程和各实验条件对陈化过程中体系pH值变化速率的影响.得出影响核壳结构的关键因素为体系的pH值变化速率,以此依据设计出钛盐浓度为1mol/L,乳胶粒浓度为230g/L的高浓度条件下批量制备TiO2空心球壳的新实验方案,最终产物保持良好的空心球结构.     

磁性碳球的制备与表征

以葡萄糖、葡萄糖酸亚铁和十六烷基三甲基溴化铵(CTAB)为原料,采用水热法结合退火处理制得磁性碳球。重点考察了水热反应中反应物的浓度、反应温度和时间等参数对样品形貌和结构的影响。利用场发射扫描电子显微镜、X 射线衍射仪、X 射线光电子能谱、红外光谱仪、热重分析仪和振动磁强计等对所制备的磁性碳球进行表征。结果表明：当葡萄糖溶液浓度0.1 mol/L、葡萄糖酸亚铁质量浓度1.667 g/L、CTAB 质量浓度6.667 g/L、温度170℃、时间12 h 时,得到了粒径尺寸均一、表面光滑、形貌规整、分散性良好并且具有一定铁磁性的碳球,其平均粒径约为600 nm。此外,分析了磁性碳球的形成机理。     

利用遗传算法优化透明质酸发酵培养基

运用遗传算法对透明质酸(HA)产生菌--马链球菌兽瘟亚种ATCC 39920发酵培养基的6种组份进行了优化研究.每个长度为36位的染色体编码一种培养基配方,以HA产量为适应度函数值对其进行评价.经过4代的进化,各参数的取值范围收敛于最优区域.最终以40个实验样本完成了6种培养基成分、64个浓度水平的优化选择.优化后的培养基的构成为:葡萄糖44.0g/L,酵母膏5.2g/L,蛋白胨8.4g/L,牛肉膏9.8g/L,KH2PO41.45g/L,MgSO42.8g/L.采用优化培养基的HA产量达0.395g/L,较原培养基提高了31.2%,生产成本也大幅度降低.     

浓度对微生物燃料电池电化学性能的影响

以大肠杆菌为微生物催化剂,亚甲基兰为电子中介体,葡萄糖为有机燃料,构建双室微生物燃料电池(MFC),考察其在不同葡萄糖浓度条件下的产电性能。设定葡萄糖浓度分别为0.001、0.006、0.011、0.034和0.056mol/L。葡萄糖浓度为0.011mol/L时,循环伏安氧化峰和还原峰最强,电池输出功率密度最大,峰值功率密度为339.69mW/m2,表明电池产电性能最佳;葡萄糖浓度为0.056mol/L时,峰值功率密度为258.32mW/m2;葡萄糖浓度为0.0011mol/L时,峰值功率密度为189.51mW/m2。结果说明,在一定范围内,提高有机燃料葡萄糖浓度有利于提高电池输出功率密度,但是浓度过高,电池输出功率密度反而下降,底物浓度对功率密度的影响出现"饱和效应"。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to