Biodegradable materials are materials that are decomposed naturally through microorganisms. Biodegradable packaging differs from conventional non-biodegradable packaging in terms of raw materials, production technology, applications, and composting. Packaging includes a wide range of materials such as paper, board, plastic, metal, glass, wood, and other materials. Biodegradable materials such as bioplastic and paper are widely used in packaging applications because of their sustainable nature, properties, and appearance. Biodegradable packaging materials are used in all levels of packaging including primary, secondary, and tertiary packaging.

关键词：生物降解材料；微生物；自然分解；原材料；生产工艺；应用程序；堆肥

查看摘要 索取原文[100页]

High-resolution soft X-ray spectroscopic observations of single hot white dwarfs are scarce. With the Chandra Low-Energy Transmission Grating, we have observed two white dwarfs, one is of spectral type DA (LB1919) and the other is a non-DA of spectral type PG1159 (PG1520+525). The spectra of both stars are analyzed, together with an archival Chandra spectrum of another DA white dwarf (GD246). Aims. The soft X-ray spectra of the two DA white dwarfs are investigated in order to study the effect of gravitational settling and radiative levitation of metals in their photospheres. LB1919 is of interest because it has a significantly lower metallicity than DAs with otherwise similar atmospheric parameters. GD246 is the only white dwarf known that shows identifiable individual iron lines in the soft X-ray range. For the PG1159 star, a precise effective temperature determination is performed in order to confine the position of the blue edge of the GW Vir instability region in the HRD. Methods. The Chandra spectra are analyzed with chemically homogeneous as well as stratified NLTE model atmospheres that assume equilibrium between gravitational settling and radiative acceleration of chemical elements. Archival EUV and UV spectra obtained with EUVE, FUSE, and HST are utilized to support the analysis. Results. No metals could be identified in LB1919. All observations are compatible with a pure hydrogen atmosphere. This is in stark contrast to the vast majority of hot DA white dwarfs that exhibit light and heavy metals and to the stratified models that predict significant metal abundances in the atmosphere. For GD246 we find that neither stratified nor homogeneous models can fit the Chandra spectrum. The Chandra spectrum of PG1520+525 constrains the effective temperature to T(sub eff) = 150 000 +/- 10 000 K. Therefore, this nonpulsating star together with the pulsating prototype of the GWVir class (PG1159-035) defines the location of the blue edge of the GWVir instability region. The result is in accordance with predictions from nonadiabatic stellar pulsation models.

关键词：白矮星；X射线光学；紫外光谱；X射线天体物理设施；磁悬浮;

查看摘要 索取原文[13页]

Cytomegalovirus retinitis is a viral inflammation of the retina. The disease is caused by cytomegalovirus, a herpes virus that attacks the photosensitive cells in the retina. If left untreated, the disease can lead to permanent blindness. Most people are exposed to cytomegalovirus at some point in their life, but the infection usually affects those with a weakened immune system such as HIV-positive patients. There are two forms of cytomegalovirus retinitis: indolent and fulminant. Some common symptoms of cytomegalovirus retinitis include blurred vision, seeing floaters, photophobia, and blind spots.

关键词：巨细胞病毒性视网膜炎；病毒性炎症；巨细胞病毒；疱疹病毒；感光细胞

查看摘要 索取原文[52页]

An electronic balance is an essential instrument for any modern science laboratory as it helps in the precise weighing of materials. It can be broadly classified into two types: top loading balance and analytical balance.

关键词：电子天平；现代科学实验室；必备仪器；精确称重

查看摘要 索取原文[62页]

Metabolites are the small molecules that are present in blood, urine, and tissues. Metabolomics or metabonomics is the scientific study of the measurement and analysis of metabolites.

关键词：代谢物；代谢组学；测量；代谢物分析；科学研究

查看摘要 索取原文[86页]

Clean coal refers to the process of reducing carbon emissions and other harmful pollutants that arise from the burning of coal for power generation to the minimum possible level. SC, USC, and IGCC technologies are clean coal technologies that are widely used for setting up new-build coal-fired power plants. The more sophisticated the technology, the higher the steam pressure and temperature requirement is for operating the plant. As a result, the thermal efficiencies improve with the usage of more sophisticated technology. As well as these three technologies, CCS is also an upcoming technology, which is capable of reducing carbon emissions drastically by 80-90 percent. This technology is used in conjunction with SC, USC or IGCC plants.

关键词：清洁煤；减少；碳排放；源于；燃煤发电

查看摘要 索取原文[81页]

Synthetic biologists must comb through vast amounts of academic literature to design biological systems. The majority of this data is unstructured and difficult to query because they are manually annotated. Existing databases such as PubMed already contain over 20 million citations and are growing at a rate of 500,000 new citations every year. Our solution is to automatically extract chemical reactions from biological text and canonicalize them so that they can be easily indexed and queried. This paper describes a natural language processing system that generates patterns from labeled training data and uses them to extract chemical reactions from PubMed. To train and validate our system, we create a dataset using BRENDA, the BRaunschweig ENzyme DAtabase, with 4387 labeled sentences. Our system achieves a recall of 0.82 and a precision of 0.88 via cross validation. On a selection of 600,000 PubMed abstracts, our system extracts almost 20% of existing reactions in BRENDA as well as many that are novel.

关键词：生物系统;生物文献;化学反应

查看摘要 索取原文[17页]

报告包括电子商务方面的重要观点、政策与环境、网购平台、行业应用、电商物流、电商金融等研究。

关键词：政策环境；网购平台；电商物流；电商金融

查看摘要 索取原文[50页]

潜力空间巨大 ，瓶颈突破过程相对漫长。新一代测序技术开启生育健康的新时代。新一代测序技术助推肿瘤的个体化治疗。大数据解读是开启疾病预警时代的关键。

关键词：生物；临床应用；新一代测序技术；生育健康；助推肿瘤；疾病预警

查看摘要 索取原文[6页]

基因测序技术日臻成熟。应用前景较为广阔、颠覆想象。基因测序产业链已实现专业化分工。

关键词：基因测序技术；应用前景；产业链；专业化分工

查看摘要 索取原文[43页]