In this manuscript, the fundamental vibration, the combination vibration and the first overtone vibration of the glycerol hydroxyl were studied by near-infrared and infrared spectroscopy. The composition and variation of hydrogen bond were analyzed by two-dimensional correlation spectroscopy and principal component analysis. The analysis revealed five types of hydroxyl and verified the existence of independent, intramolecular, as well as intermolecular, hydrogen bond hydroxyl. The principal component analysis showed that there were three main forms of glycerol association: the first and second principal components explained the majority of the spectral features, and the third was mainly the independent hydroxyl. The results provided insight into the structure of glycerol and illustrated the potential for using these tools in analyzing bonding in even more complex systems.

The hydrogen bond (H-bond) is one of the most important intra- and inter molecular attraction in chemistry, while the hydroxyl is one of the chemical groups that forms H-bond most easily. Therefore, a detailed understanding of the hydroxyl group is essential to a fundamental understanding of the H-bond. In this paper, the molecular structures especially the H-bond were investigated through the near infrared spectra (NIR) of n-propanol and n-butanol over a temperature range of 36-76 degrees C (or 36-79 degrees C) using two-dimensional correlation spectroscopy (2D-Correlation) techniques. The following results were drawned:1) the change of the hydroxyl vibrational frequency is caused by the breakage of H-bonds as the temperature increases, the vibrational frequencies of the H-bonds and free hydroxyl remain unchanged. However, the spectral peak positions shifted as the changed of H-bonds and free hydroxyl's composition. 2) when the temperature rose, the absorption of the free hydroxyl vibration in the first overtone region increased faster than H-bonded hydroxyl was reduced, which means that the frequency of H-bonded hydroxyl shifted to higher frequency before breaking. However, in the combination vibration region where both free hydroxyl and H-bonded hydroxyl overlapped, the situation is just the opposite; that is, the change of H-bonded hydroxyl is faster than in free hydroxyl. This difference may be related to the symmetry of hydroxyl's combination vibration. 3) With the increased temperature, the combination absorption will be partially converted to overtone vibration absorption, and the combination vibration absorption of n-propanol will be changed more easily into the first overtone absorption than is the case for n-butanol due to poor symmetry. 4) Principal component analysis (PCA) leads the authors to propose three possible states of hydroxyl bonding: free (non-H-bonding) hydroxyl, inter-hydroxyl group binding (through one or two H-bonds), and a weak force bonding (less bond energy than H-bonding) between the hydroxyl and alkyl groups on different molecules. (C) 2019 Elsevier B.V. All rights reserved.

目的设计并合成具有抗肿瘤活性及逆肿瘤耐药作用的蛇葡萄素与5-氟尿嘧啶拼合物。方法以氯乙酸为连接基团,将蛇葡萄素与5-氟尿嘧啶进行酯化拼合,采用MTT法检测拼合物对人白血病细胞K562及其耐药株K562/ADR的抑制作用。结果经分离纯化及结构鉴定,获得了两个新的蛇葡萄素与5-氟尿嘧啶拼合物,其对K562细胞的IC50分别为(11.62±2.20)和(10.34±0.60)μmol/L,并能部分逆转K562/ADR细胞对阿霉素的耐药性。结论新拼合物在体外初步显示出良好的抗肿瘤活性及逆转肿瘤细胞耐药的作用。

This study reports two novel 5-fluorouracil-substituted ampelopsin derivatives. The structures of two new derivatives were characterized by elemental analysis, 1H-NMR, 13C-NMR, IR and MS. Their anticancer activities in vitro against two cancer cell lines, K562 and K562/ADR, were investigated using the MTT assay, and the results showed that the two new compounds were more effective than reference drugs such as ampelopsin and verapamil.

The main issue with regard to improving the heating ability of reflow ovens is to minimize the temperature difference ∆T among the various parts of the printed circuit board (PCB) during the reflow soldering process. We need to control temperature within a much narrower process margin when we use lead-free soldering. Accordingly, our development target in this work is to achieve a significant increase in heat transfer coefficient α, fundamental to the heating performance of a reflow oven. We have developed a new model of reflow oven for lead-free soldering with a much higher heating ability by redesigning the hot air blowing unit, specifically by changing the design of the hot air panel. We were able to achieve this target in only five months by using process diagnostic techniques such as direct measurement of heat transfer coefficient and flow visualization, which we have developed and used for various applications. ABSTRACT

OBJECTIVE:The objective of this study was to explore our experience in the treatment of serious burn patients (total burn surface area [TBSA] > 90% and full thickness burns > 70% TBSA).METHODS:Thirty patients who were admitted to our unit over a period of 12 years were analyzed retrospectively; 23 cases (76.7%) were successfully treated.RESULTS:There were seven out of 12 cases (58.3%) in the first 5 years and 16 out of 18 cases (88.9%) in the latter 7 years of the study period.CONCLUSIONS:It is concluded that: 1) giving electrolyte-free fluids (around 3700 ml) and the maintenance of hourly urine output at 70 ml or more appear to be beneficial in resuscitation therapy; 2) the first operative procedure should be undertaken early, at about the third day after injury; 3) a higher percentage area of eschar to be excised in the first operation is encouraged and eschar excision of up to 40% or more is preferable; 4) controlling the area of exposed wound under 5% in the entire therapeutic course is essential in the prevention of burn infection; 5) emphasis should be placed on the vital role of a dehumidifier in reducing the incidence of fungal infection; and 6) early enteral nutrition with the use of growth hormone in correcting the nutritional state of the patient is also emphasized.

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations on a suite of mid-ocean ridge basalts (MORB) reveal abundant interstitial glass, which differs in occurrence and composition from basaltic glass at pillow rims. Interstitial glass consists dominantly of SiO2 and Al2O3 and is depleted in other cations, representing a highly differentiated residual material. Low-temperature alteration by seawater solutions results in the formation of saponite (Mg-rich variety of smectite) replacing the interstitial glass; the Si/Al ratio of this saponite reflects that of the source glass. Chemical changes during this transition differ from those resulting from alteration of basaltic or rhyolitic glass. Alteration of interstitial glass results in uptake of Mg and Fe and loss of Si and Al, but there is little or no leaching of alkalis. This reflects a strong control on chemical reactions by solution composition (high Na and Mg concentrations of seawater fluids). In contrast to basaltic glass at pillow rims, our observations do not reveal microbial activities in the alteration of interstitial glass.

Mid‐ocean ridge basalt (MORB) samples, varying in age from Recent to Jurassic, were selected for electron microscopic and rock magnetic studies. Our observations indicate that the degree of oxidation of titanomagnetite in MORB increases only gradually with sample age. The titanomagnetite in recent MORB (<20,000 years) shows no sign of alteration (z∼0). Quaternary samples near the ridge (<2 Ma) typically have z values of less than 0.35, indicating a low degree of oxidation, whereas samples with ages of tens of millions of years have z values of up to 0.9. Some older samples show lower z values, but the upper envelope of our observations in a z versus age plot can be represented by the function z = p + q log t, where p ≈ 0.38, q ≈ 0.38, and t is in millions of years (for t>100 ka). Both electron microscopic observations and rock magnetic data support the notion that low‐temperature oxidation of titanomagnetite to titanomaghemite in MORB is a gradual process. Moreover, the rate of maghemitization is controlled by many factors on both macroscopic and microscopic scales, including regional oceanic crustal structures, lithological features, grain size, and surrounding matrices. Pillow lavas and the tops of massive flows tend to have higher degrees of oxidation than the interiors of massive flows, owing to higher porosity and permeability of the former. In contrast, interstitial glass can protect fine titanomagnetite grains from alteration. The natural remanent magnetization (NRM) intensity of MORB varies as a function of age, magnetic granulometry, concentration of magnetic materials, and the degree of alteration. Fine‐grained MORB samples typically have higher NRM intensity. The NRM intensity appears to decrease substantially with increasing degree of maghemitization and, hence, with age. The envelope of the smoothed magnetic anomaly amplitudes resembles the change in NRM intensity for MORB samples of the last 30 million years, but the underlying assumption that the highest degree of maghemitization observed in the samples of a given age is entirely responsible for these intensity changes is not supported. Maghemitization of the micrometer‐sized and larger grains is probably only partly responsible, whereas a significant contribution to NRM intensities is inferred from those submicrometer‐sized titanomagnetite grains that remained protected from oxidation by the surrounding matrix of interstitial glass.

Transmission electron microscopy observations and rock magnetic measurements on a pillow from the ‘New Flow’, extruded in 1993 at the Juan de Fuca Ridge, demonstrate that Ti-content in large (up to 40 μm) titanomagnetite grains varies as a function of the cooling rate. Large grains in the interior of the pillow have a narrow composition range of approximately x=0.6, where x represents the ulvöspinel content in the solid solution series with magnetite. In contrast, the titanomagnetite grains near the pillow rim are progressively smaller and have a broad composition range (average x=∼0.45). Within 0.5 cm of the rim a significant portion of the grains is single domain (SD) to superparamagnetic (SP) and appears to have little or no Ti. This lower Ti-content provides a ready explanation for the higher Curie temperature near the glassy margin of the pillow. Moreover, determination of the oxidation state of the titanomagnetite does not show low temperature oxidation anywhere within the pillow, indicating no rapid alteration to titanomaghemite as previously suggested for this very young mid-ocean ridge basalt (MORB) in order to explain the Curie temperatures. Submicrometer titanomagnetite in interstitial glass in the interior of the pillow also shows variable x values. These grains make contributions to susceptibility that show up as high (up to ∼580°C) Curie temperatures in thermomagnetic analyses and they appear to be SD to SP. The variation of x values for the titanomagnetite in the MORB is consistent with thermodynamic and kinetic considerations, because crystallization of titanomagnetite in the MORB is controlled by processes depending on cooling rate and crystal-melt fractionation.

Transmission electron microscopy observations and rock magnetic measurements reveal that alteration of fine- and large-grained iron-titanium oxides can occur at different rates. Fine-grained titanomagnetite occurs as a crystallization product within interstitial glass that originated as an immiscible liquid within a fully differentiated melt; in several samples with ages to 32 Ma it displays very little or no oxidation ( z ≈ 0). In contrast, samples with ages of 10 Ma or older are observed to also contain highly oxidized ( z ≥ 0.66) large-grained titanomaghemite. These large grains, having originated by direct crystallization from melt, are associated with pore space. Such pore space can serve as a conduit for fluids that promote alteration, whereas fine grains may have been “armored” against alteration by the glass matrix in which they are embedded. Apparently, alteration of oceanic crust is a heterogeneous process on a microscopic scale. The existence of pristine, fine-grained titanomagnetite in the interstitial glass of older ocean-floor basalts that have undergone significant alteration implies that such glassy material is capable of carrying original thermal remanent magnetization and may be suitable for paleointensity determinations.

A transmission electron microscopy (TEM) method, higher‐order Laue zone (HOLZ) diffraction, has been applied to measurement of accurate lattice parameters of individual titanomagnetite and titanomaghemite grains. Lattice parameters and cation‐composition data are obtained with TEM/analytical electron microscopy (AEM) for individual grains smaller than 0.1 μm in diameter. A suite of Ocean Drilling Program/Deep Sea Drilling Project ocean‐floor basalts containing titanomagnetite‐titanomaghemite with a wide range of oxidation degree (z), were employed to establish the relationship between lattice parameter (a), z and Ti‐content (x) for naturally occurring samples. Standardization was accomplished with measurements on grains sufficiently large to allow the determination of absolute oxygen contents by electron microprobe analyses, which directly yielded z values. The probe data confirm that the maghemitization process in ocean‐floor basalts is one involving loss of iron and indicate a nearly linear relationship between lattice parameters and oxidation degrees for a given x value, except for the smallest and largest values of z. The standardized relation permits determination of z for individual submicrometer‐sized grains using only measured a‐values and cation compositions as determined by HOLZ diffraction and AEM.

Fourteen cases suffering full-thickness burns of more than 70 per cent total body surface area (TBSA) have been successfully treated during the last 8 years (1988-1995). Among these patients, 10 cases suffered from burns of more than 90 per cent TBSA. Five cases had full-thickness burns of 80-90 per cent TBSA. Escharectomy, followed by coverage of wounds with a homograft to the lower surface of which, adjacent to the wound bed, microautoskin grafts had been attached was employed to close wounds in the early stages after burn. The remaining non-surgically treated wound was treated by exposure and topical silver sulfadiazine. The temperature and humidity of the ward was controlled by air conditioning and dehumidification. Aggressive excision of eschar and auto-skingrafting was carried out 3 weeks post-injury. Strictly limiting the uncovered wound to less than 5 per cent appeared to be the major effective measure in preventing burn infection.

High resolution electron microscope studies have been carried out on 'zero-age' (New Flow) basalts from the Juan de Fuca Ridge and on young (< 20 ka) basalts from the axis of the East Pacific Rise at 12°N. Such data lead to characterization of the magnetic minerals, especially those of smaller grain size, which have been hypothesized by Kent and Gee to have undergone grain size-dependent alteration. In addition to larger titanomagnetite grains, abundant submicrometer titanomagnetite has been observed in globules within a glassy matrix. These grains, likely to be single-domain (SD) or superparamagnetic, are associated with apatite, uncommon pyrrhotite and residual glass. The submicrometer titanomagnetite grains have a wide compositional range (0 < x < 0.8), where x is the fraction of ulvöspinel component, whereas the larger, multi-domain (MD)-sized titanomagnetite grains have a narrow composition range of approximately x = 0.6. This variability in Ti content provides a ready explanation for the thermal rock magnetic properties observed by Kent and Gee and eliminates the need to invoke extremely rapid (< 20 ka) alteration of these young basalts.

In a previous paper by the authors, the results of M s temperature measured by a dilatometry, are not the real M s of �� �� �� martensitic transformation, but the temperature of the �� �� �� transformation created by a demanganization layer at the surface of specimen, which are identified by their latest experimental results. Presented are the results of the reexamination of the dilatational experiments of the alloy.

Austenite (γ) reversion in a cold-rolled 17.6 wt.% Mn steel was tracked by means of dilatometry and in-situ magnetic measurements during slow continuous annealing. A splitting of the γ-reversion into two stages was observed to be a result of strong elemental partitioning between γ and α′-martensite during the low temperature stage between 390 and 575 °C. Atom probe tomography (APT) results enable the characterization of the Mn-enriched reversed-γ and the Mn-depleted remaining α′-martensite. Because of its lower Mn content, the reversion of the remaining α′-martensite into austenite takes place at a higher temperature range between 600 and 685 °C. APT results agree with partitioning predictions made by thermo-kinetic simulations of the continuous annealing process. The critical composition for γ-nucleation was predicted by thermodynamic calculations (Thermo-Calc) and a good agreement was found with the APT data. Additional thermo-kinetic simulations were conducted to evaluate partitioning-governed γ-growth during isothermal annealing at 500 °C and 600 °C. Si partitioning to γ was predicted by DICTRA and confirmed by APT. Si accumulates near the moving interface during γ-growth and homogenizes over time. We used the chemical composition of the remaining α′-martensite from APT data to calculate its Curie temperature (TCurie) and found good agreement with magnetic measurements. These results indicate that elemental partitioning strongly influences not only γ-reversion but also the TCurie of this steel. The results are important to better understand the thermodynamics and kinetics of austenite reversion for a wide range of Mn containing steels and its effect on magnetic properties.

A 304 N austenitic stainless steel possessing excellent performance through the addition of nitrogen, combined with deformation and incomplete recrystallization annealing processes was obtained. The results reveal that the solid solution of 0.15 wt% nitrogen in austenite tremendously enhances the yield strength of the 304 N sample (from 285 MPa to 581 MPa) while maintaining sufficiently high elongation (about 50%). Compared with the 304 reference steel, the interstitial nitrogen not only brings significant solid solution strengthening effect, but also greatly stabilizes the austenite, so as to avoid stress-induced martensitic transformation at the early elastic stage that leads to premature yielding. Moreover, nitrogen promotes recrystallization process and dislocation planar slip, which effectively improves the capacity to accommodate dislocations of austenite and sustains high flow stress under equivalent strain level, thus maintaining high elongation of the steel. This study is a new attempt to develop high strength and ductility stainless steels without changing the chemical composition of materials.