Semi-quantitative analysis of the structural evolution of mesophase pitch-based carbon foams by Raman and FTIR spectroscopy

Graphitized carbon foams(GFms)were prepared using mesophase pitch(MP)as a raw material by foaming(450℃),pre-oxidation(320℃),carbonization(1000℃)and graphitization(2800℃).The differences in structure and properties of GFms prepared from different MP precursors pretreated by ball milling or liquid phase extraction were investigated and compared,and semi-quantitative calculations were conducted on the Raman and FTIR spectra of samples at each preparation stage.Semi-quantitat-ive spectroscopic analysis provided detailed information on the structure and chemical composition changes of the MP and GFm de-rived from it.Combined with microscopic observations,the change from precursor to GFm was analyzed.The results showed that ball milling concentrated the distribution of aromatic molecules in the pitch,which contributed to uniform foaming to give a GFm with a uniform pore distribution and good properties.Liquid phase extraction helped remove light components while retaining large aromatics to form graphitic planes with the largest average size during post-treatment to produce a GFm with the highest degree of graphitization and the fewest open pores,giving the best compression resistance(2.47 MPa),the highest thermal conductivity(64.47 W/(m·K))and the lowest electrical resistance(13.02μΩ·m).Characterization combining semi-quantitative spectroscopic ana-lysis with microscopic observations allowed us to control the preparation of the MP-derived GFms.

A review of the catalytic preparation of mesophase pitch

Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.

《中长期青年发展规划》在青年门户网站的新闻报道——基于“中青在线”的数据分析

2017年4月13日,《中长期青年发展规划(2016-2025年)》发布,这对青年发展无疑具有重大的历史现实和意义。分析"中青在线"近一万条数据,发现涉及青年的报道总体数量有所增长,其数量变化不因"规划"时效性的减弱而减少,但受该时段时事新闻影响。媒体的关注重点没有变化,部分领域及措施长期得不到重视。"规划"提及的10个领域中,媒体报道最多的是"青年社会融入与社会参与"类新闻,最少的是"预防青少年违法犯罪"类新闻。可见媒体在议程设置方面,略偏向新闻专业主义和商业新闻主义,所涉及议题以受众感兴趣的长期话题为主,而不是迫切需要得到关注的青年问题。作为主要报道青年新闻的网站,"中青在线"要及时对青年问题加以关注,增加对"规划"的宣传报道,提升其作为主要青年门户网站的自觉性。

理想戏剧网的构建与崩溃——试论40年代国民党官方戏剧理念于中央青年剧社的实践与推广

抗战时期,国民党要员鲁觉吾提出以"中央青年剧社"(以下简称"中青")为核心,各地青年剧社为散点,由中央统一管理地方,构建由上而下的"青年戏剧网"这一理想。虽宣扬以戏剧的手段实现三民主义,其实质却是对张道藩《我们需要的文艺政策》的刻骨遵从,代表着上世纪40年代国民党官方戏剧理念于官办剧团的推广与实践,暗含将官办剧团化为党政宣传最好的工具的真实用意。由于该理念锁定了"中青"对各地青年剧社的领导地位,在具体实施中,官方代言人鲁觉吾拟以拓展青年戏剧运动、解决"剧本荒"为契机,借助"中青"对各地青年剧社的辅导工作,将官方定义的"最理想、最标准"的剧本推广到大后方各地,以诱导大众认同官方意志。但事实证明,国民党当局虽有戏剧理念的推行,却未有效建立实践中与之相配合的剧团扶植政策与管理体系;虽有成型的剧本,却从根本上与大众意识相悖,难以在直面大众、日益职业化的官办剧团舞台上上演,这致使官办剧团渐趋偏离了充当官方意志代言体的既定轨道。但由于官方当局对官办剧团的牢控,官办剧团无法彻底完成"职业化"的蜕变,抗战末期的"中青"只能处于得过且过、毫无建树的状态,最终遭到裁撤,"青年戏剧网"也隨之趋于崩溃。

Rheological properties of warm mix asphalt binder by DSR test at medium temperature

The rheological properties including the complex modulus G＊ and the phase angle δof matrix and warm mix asphalt （WMA）binders were measured by using the dynamic shear rheometer （DSR ） test at the medium temperature ranging from 16 to 40 ℃,and the relationships between the fatigue factor G＊ sinδand the matrix binder property,WMA additive and test temperature were established.It is found that G＊ decreases with the increasing temperature while δincreases inversely,and G＊ of the asphalt binder with high WMA additive dosage is large,and δis small.G＊sinδexponentially decreases with the increasing temperature and linearly increases with the increase in additive dosage,and the amplitudes of variation are large at low temperatures and high additive dosages.The effect of WMA additive on the rheological property is more remarkable for the matrix asphalt binder with low G＊.Besides,aging has a great effect on the property of matrix asphalt binder,and a slight effect on the interaction between asphalt and additive.The high additive dosage can increase the fatigue cracking potential of the asphalt binder.

Rutting resistance of asphalt mixtures in the middle course

In order to improve the rutting resistance of asphalt mixtures in the middle course to reduce the rutting of asphalt pavement, the influence of different types of gradation with their own optimal asphaltaggregate ratios is analyzed. Some investigations are made out on the mixture in the middle course through the modified wheel tracking test in air bath and the Hamburg wheel tracking test （HWTT） in water bath, and the results of which are compared with the corresponding research in Germany. Results show that the Sup20 and the modified AC-20I have better performance than that of AC-20I under the same test conditions. In addition, the high-quality bitumen and hard aggregate can improve the rutting performance of the mixture in water-submerged conditions. The selection of modified asphalt, hard aggregate and a reasonable gradation are essential to the improvement of the rutting resistance of the mixtures used in the middle course.

Changing patterns of colorectal cancer in China over a period of 20 years

AIM： To determine whether any changes have occurred on the patterns of colorectal cancer in China. METHODS： Data from 21 Chinese articles published from 1980 to 1999, were used to analyze the time trend of colorectal cancer according to the patients＇age at diagnosis, sex, the site of the tumor, stage, and the pathology. RESULTS： From 1980s to 1990s, the mean age of the colorectal cancer patients has increased. The percentage of the female patients rose. The distribution of colorectal carcinoma shows a predominance of rectal cancer. However, the proportion of proximal colon cancer （induding transverse and ascending colon） increased significantly accompanied by a decline in the percentage of rectal cancer. Similarity in the percentage of distal colon cancer between two decades was revealed. In the 1990s, statistically more Stage B patients were found than those in 1980s. In addition, databases show a significant decrease in the Stage D cases. The proportion of adenocarcinoma increased, but the mucinous adenocarcinoma decreased during two decades. CONCLUSION： These findings indicate that the pattern of colorectal cancer in China has been changing. Especially, a proximal shift due to the increasing proportion of ascending and transverse colon cancer has occurred in China.

Active Tectonics and Erosional Unloading at the Eastern Margin of the Tibetan Plateau

The eastern margin of the Tibetan Plateau is marked by an extremely steep mountain front with relief of over 5 km. This topography,coupled with abundant Mesozoic thrusts within the margin,explains why tectonic maps of the India-Asia collision typically show the eastern margin as a major thrust zone. Actually,it does not like that. Field observations suggest that the margin is better characterized as a zone of NNE-directed dextral shear with extensive strike-slip faulting and secondary thrusting. The high relief and steep gradients are partially explained by erosional unloading of an elastic lithosphere;the pre-erosion inherited topography may be the inherited Mesozoic thrust belt landscape modified by a component of Cenozoic tectonic shortening.

Clinicopathologic characteristics of gastric carcinoma in elderly patients: A comparison with young patients

AIM:To examine the clinicopathologic features of elderly patients with gastric carcinoma and to investigate the relationship between prognosis and age.METHODS: We reviewed the hospital records of 2 014patients with gastric carcinoma retrospectively to compare the clinicopathologic findings in elderly (age ＞70 years) and young (age ＜36 years) patients during the period from 1986 to 2000 in a tertiary referral center in Gwangju, Korea. Overall survival was the main outcome measure.RESULTS: Of the 2 014 patients, 194 (9.6%) were in the elderly group and 137 (6.8%) were in the young group.The elderly and young patients had similar distributions with respect to depth of invasion, nodal involvement, hepatic metastasis, peritoneal dissemination, tumor stage at the initial diagnosis, and type of surgery. Synchronous multiple carcinomas were found in 14/194 (7.2%) of the elderly group and 4/137 (2.9%) of the young group (P＜0.05). Using the Borrmann classification, type Ⅳ was more frequent in the young patients than in the elderly patients (P＜0.05).Significantly more elderly patients had a well or moderately differentiated histology, and more young patients had a poorly differentiated histology and signet ring cell carcinoma (P＜0.001). The 5-year survival rates of elderly and young patients did not differ statistically (52.8% vs 46.5%,P = 0.5290). Multivariate analysis showed that the histologic type, nodal involvement and operative curability were significant prognostic factors, and age itself was not an independent prognostic factor of survival for elderly gastric carcinoma patients.CONCLUSION: Elderly patients with gastric carcinoma do not have a worse prognosis than young patients. The important prognostic factor is whether the patients undergo a curative resection.

A Comprehensive Evaluation of Tourism Climate Suitability in Qinghai Province, China

Qinghai Province is an important component of the Qinghai-Tibet Plateau in China. Scientific evaluation of the suitability of Qinghai's climate for tourism can contribute to overcoming obstacles posed by climate on sustainable tourism development in Qinghai Province, including disparities between the low and high seasons, high altitude health concerns, and weather events. A tourism climate suitability evaluation model of the Qinghai-Tibet Plateau is constructed (Tourism Climate Suitability Index, or TCSI), and tourism climate suitability is comprehensively evaluated for Qinghai Province from climate data from 1960 to 2009. Results show that: (I) There is clear distributional characteristics of spatial-temporal variability of TCSI values in Qinghai Province. (II) Tourism climate suitability in Qinghai Province has significant seasonal and regional differences. The year is divided into a very suitable period (July and August), suitable tourism periods (from April and October), less suitable periods (From Nov to Mar). June to August is the most suitable tourism period in Qinghai. Qinghai Province is divided into five levels of tourism climate suitability: most suitable regions, very suitable regions, suitable regions, less suitable regions, and unsuitable region. (III) The key factor which influences regional differences in tourism climatic suitability is atmospheric oxygen. And the key factors which chiefly influence seasonal differences of tourism climate suitability are temperature and humidity, the wind chill factor, and barrier weather.

我国企业风险投资介入模式的比较选择

如何选择适合自身发展的风险投资介入模式 ,对于我国的风险投资企业具有特别的意义。文章通过比较风险投资几个主要介入模式的优缺点 ,对不同情况的风险投资企业所适用的投资介入模式进行了分析 ,并对所应采取的选择策略进行了探讨。

Glacier Extent and Volume Change(1966～2000) on the Su-lo Mountain in Northeastern Tibetan Plateau,China

The topographic maps of 1:50,000 scales,aerial photographs taken in 1966,one Landsat image taken in 1999,and SRTM data from 2000 were used to quantify the losses in area and volume of the glaciers on the Su-lo Mountain,in the northeastern Tibetan Plateau,China in the past 30 years.The total glacier area decreased from 492.9km2 in 1966 to 458.2km2 in 1999.The volume loss of the studied glaciers reached 1.4 km3 from 1966 to 2000.This agrees with documented changes in other mountain glaciers of the whole Tibetan Plateau.

Six New Species of Sawflies from Gansu and Qinghai Provinces of China (Hymenoptera: Tenthredinidae)

Three new Tenthredinidae species are reported from Gansu and three from Qinghai Provinces of China. Tenthredo （Tenthredo） sinotemula sp. nov., Tenthredo （Tenthredella） labrangensis sp. nov. and Tenthredo （Tenthredella） sinosimplex sp. nov. are described from Gansu, Tenthredo （Tenthredella） rolleri sp. nov., Tenthredo （Tenthredella） qinghaiensis sp. nov. and Tenthredo （Tenthredella） yunningsiensis sp. nov. from Qinghai Province.

Studies on frozen ground of China

Permafrost in China includes high latitude permafrost in northeastern China, alpine permafrost in northwestern China and high plateau permafrost on the Tibetan Plateau. The high altitude permafrost is about 92% of the total permafrost area in China. The south boundary or lower limit of the seasonally frozen ground is defined in accordance with the 0 ℃ isothermal line of mean air temperature in January, which is roughly corresponding to the line extending from the Qinling Mountains to the Huaihe River in the east and to the southeast boundary of the Tibetan Plateau in the west. Seasonal frozen ground occurs in large parts of the territory in northern China, including Northeast, North, Northwest China and the Tibetan Plateau except for permafrost regions, and accounting for about 55% of the land area of China. The southern limit of short-term frozen ground generally swings south and north along the 25° northern latitude line, occurring in the wet and warm subtropic monsoon climatic zone. Its area is less than 20% of the land area of China.

Antioxidant Activity of Isothiocyanate Extracts from Broccoli

Isothiocyanates(ITCs) extracts were prepared from fresh broccoli.Their antioxidant properties were evaluated by using the in vitro bioassays,including superoxide anion radical( 2 O·-) ,hydroxyl radical(HO·-) and 2,2-diphenyl-1-picrylhydracyl(DPPH·) radical-scavenging methods,lipid peroxidation assay,and reducing power assay.The ITCs extracts exhibited significant dose-dependent antioxidant activities(P<0.01) .Its antioxidant-stability was affected by temperature and storage condition,although it was more stable than vitamin C(Vc) .GC-MS iden-tified sulforaphane in the ITCs extracts.The antioxidant activity of sulforaphane was approximately one tenth to one fifth of that of Vc.Sulforaphane was experimented to be one of dominating contributors to antioxidant capacity of ITCs extracts.However,there was no direct antioxidant activity found for benzyl isothiocyanate(BITC) in vitro. Therefore,it could be concluded that the general group(-N=C=S) was not the essential part for the antioxidant activity of sulforaphane.It is suggested that the ITCs extracts from broccoli can be developed into a promising food additive for healthy food.

Correlation of Dust Storms in China with Chlorophyll a Concentration in the Yellow Sea between 1997-2007

Based on daily observation data at 222 meteorological stations in China,the characteristics of dust storms between 1997 and 2007 were examined.Next,the relationship between dust events and chlorophyll (Chl) a concentration in the Yellow Sea was investigated.There were six regions with high annual frequencies of dust storms.The seasonal distribution of dust storms showed spatiotemporal variation.The six regions with highest annual frequencies also exhibited high frequencies of dust storms in spring.Dust storms in most regions occurred in spring.Of all dust storms in China,sixty-five percent of all dust storms occurred during the spring.The area and frequency of dust storms were smaller in fall and winter than in spring and summer.A significant correlation was found between dust events and Chl a concentration in the Yellow Sea.High correlation regions included Qinghai-Xizang region,part of the Hexi Corridor,the western Inner Mongolia and Hetao Regions,and the Hunshandake Desert.The high correlation may be induced by the high ratio of dust storms in the abovementioned regions that arrive over the Yellow Sea,as inferred through a forward trajectory analysis;especially notable is dust transported at a lower altitude (< 3 km).

The advertisement call of the giant spiny frog Paa spinosa

We analyzed the advertisement call of Paa spinosa at Yuliang Mountain,Lanxi,Zhejiang Province,in eastern China.Temporal and spectral call parameters were analyzed,along with call intensity.Calls comprised of three to seven notes,the last of which had the longest duration.Three formants(harmonics)were clearly distinguishable from the audio spectrogram.The dominant frequency ranged from 411-1534 Hz,and was either the first or the second formant.The number of notes within a call was positively correlated to air temperature,so that calls contained more notes during the day.Also,the dominant frequency appeared to be lower at the highest temperature.

The influence of plant root system architectural properties upon the stability of loess hillslopes,Northeast Qinghai,China

To investigate the influence of root system architectural properties of three indigenous （cold- adapted） shrubs on the hillslope stability of loess deposits in the Xining Basin, northeast part of Qinghai-Tibet Plateau （QTP）, indoor direct shear tests have been conducted on the remolded rooted soil of three shrubs. Test results show that root system architectural indices （root area ratio （RAR）, root length density （RLD） and root density （RD）） of the shrubs decline with depth and the relationship between RAR, RD and depth is exponential, while a power relationship describes the relationship between RLD and depth. The cohesion force of remolded rooted soil for the shrubs initially increases with depth, but it then demonstrates a slightly decreasing trend, which can be described with a power relationship. Power relationships also describe relationships between cohesion force and RAR, RLD and RD for the shrubs. As the growth period increases from lO to 17 months, the incremental increase in RAR is 48.32% ~ 21o.25% for Caragana korshinskii Kom and 0.56% ~ 166.85% for ZygophyUum xanthoxylon （Bunge） Maxim. This proportional increase is notably larger than that for RLD and RD. The increment in RAR is marginally greater for C. korshinskff than it is for Z. xanthoxylon. Correspondingly, the cohesion force incremental rates of remolded rooted soil for C. korshinskii and Z. xanthoxylon are 12.41% ~ 25.22% and 3.45% ~ 17.33% respectively. Meanwhile, as root content increases, the contribution by roots to cohesion force increases markedly until a threshold condition is reached.

Applications of Three DNA Barcodes in Assorting Intertidal Red Macroalgal Flora in Qingdao, China

This study is part of the endeavor to construct a comprehensive DNA barcoding database for common seaweeds in China. Identifications of red seaweeds, which have simple morphology and anatomy, are sometimes difficult solely depending on morphological characteristics. In recent years, DNA barcode technique has become a more and more effective tool to help solve some of the taxonomic difficulties. Some DNA markers such as COI（cytochrome oxidase subunit I） are proposed as standardized DNA barcodes for all seaweed species. In this study, COI, UPA （universal plastid amplicon, domain V of 23S rRNA）, and ITS （nuclear internal transcribed spacer） were employed to analyze common species of intertidal red seaweeds in Qingdao （119.3°-121°E, 35.35°-37.09°N）. The applicability of using one or a few combined barcodes to identify red seaweed species was tested. The results indicated that COI is a sensitive marker at species level. However, not all the tested species gave PCR amplification products due to lack of the universal primers. The second barcode UPA had effective universal primers but needed to be tested for the effectiveness of resolving closely related species. More than one ITS sequence types were found in some species in this investigation, which might lead to confusion in further analysis. Therefore ITS sequence is not recommended as a universal barcode for seaweeds identification.

Characteristics of the microzooplankton community in Jiaozhou Bay,Qingdao,China

The species composition and abundance of microzooplankton at 10 marine and five coastal stations （Hongdao, Daguhe, Haibohe, Huangdao and Hangxiao） in the Jiaozhou Bay （Qingdao, China） were studied in 2001. The microzooplankton community was found to be dominated by Tintinnopsis beroidea, Tintinnopsis urnula, Tintinnopsis brevicoUis and Codonellopsis sp. The average abundance of microzooplankton was highly variable among stations. Specifically, the abundance of microzooplankton was higher at inshore stations and lower in the center of the bay （St. 5）, bay mouth （St. 9） and outside the bay （St. 10）. The highest average annual densities （346 ind./L） was observed at St. 3, while the lowest （55 ind./L） was at St. 10. Two abundance peaks were recorded in May （324 ind./L） and February （300 ind./L）. The distribution of microzooplankton in three sampling layers at the 10 stations was relatively homogenous and the abundance decreased slightly as the water depth increased. At coastal stations, the highest average annual density was recorded at Hongdao Station （677 ind./L）, followed by Daguhe Station （616 ind./L）, Haibohe Station （400 ind./L ）, Huangdao Station （275 ind./L） and Hangxiao Station （73 ind./L）. Furthermore, a 24-h sampling analysis conducted at Hangxiao Station revealed that the microzooplankton assemblages were characterized by a bimodal diel vertical migration pattem, with the highest densities occurring at dusk （154 ind./L）, followed by dawn （146 ind./L）, noon （93 ind./L） and midnight （77 ind./L）. The density of microzooplankton in the Jiaozhou Bay was in the middle range of the densities of temperate coastal waters worldwide.